Cryogenic liquid two-stage supercharging system and cryogenic liquid two-stage supercharging assembly

Abstract

The invention provides a low-temperature liquid two-stage supercharging system and a low-temperature liquid two-stage supercharging assembly. The low-temperature liquid two-stage supercharging system comprises a piston cylinder, a piston rod and a piston rod, the piston is arranged in the piston cavity and movably connected with the piston cavity, the piston cavity is divided into a low-pressure cavity and a high-pressure cavity, a first liquid inlet and a first liquid outlet which are communicated with the low-pressure cavity and a second liquid inlet and a second liquid outlet which are communicated with the high-pressure cavity are formed in the side wall of the piston cylinder in a penetrating mode, and the first liquid inlet is communicated with a liquid inlet pipe; a first one-way valve is arranged in the liquid inlet pipe, a conducting pipe is communicated between the first liquid outlet and the second liquid inlet, a second one-way valve is arranged in the conducting pipe, the second liquid outlet is communicated with the liquid outlet pipe, and a third one-way valve is arranged in the liquid outlet pipe; the first end of the transmission shaft penetrates through the piston cylinder, is movably connected with the piston cylinder and is fixedly connected with the piston in the high-pressure cavity; the driving assembly is in driving connection with the second end of the transmission shaft. According to the invention, a higher supercharging effect can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of low-temperature supercharging, and in particular to a low-temperature liquid two-stage supercharging system and a low-temperature liquid two-stage supercharging assembly. Background Art

[0002] At low temperatures, gas can be stored in a storage container in a liquefied form to obtain a higher storage density. Supplying liquefied gas to the vaporizer at a higher pressure can directly obtain higher pressure gas without compression during the gas filling process, which is much more efficient than the gas compression process.

[0003] In order to supply the liquefied gas fuel to the gasifier with a high enough pressure, a low-temperature booster pump is usually used to pump the liquefied gas. The pressure of the pump is transmitted to the piston in the piston cylinder through the drive shaft by the drive end to boost the cryogenic liquid. During the stroke, the drive end drives the drive shaft and the piston to compress the liquid for boosting and discharge. During the return stroke, the drive end drives the drive shaft and the piston to move in the opposite direction, so that new liquid is added to the piston cylinder. That is, the cryogenic liquid is only compressed and boosted in one direction during the stroke. In order to reduce the heat transfer between the cryogenic liquid and the drive end, a longer transmission rod is usually set to reduce the heat transfer, which makes the one-way compression boosting structure unable to achieve a higher boosting effect. Summary of the invention

[0004] In view of this, the present invention provides a cryogenic liquid two-stage boosting system and a cryogenic liquid two-stage boosting assembly to solve the technical problem that the cryogenic boosting pump in the prior art cannot achieve a higher boosting effect.

[0005] The low-temperature liquid two-stage pressurization system provided by the present invention comprises:

[0006] A piston cylinder, wherein a piston chamber is provided in the piston cylinder;

[0007] A piston, wherein the piston is arranged in the piston chamber, movably connected to the piston chamber, and divides the piston chamber into a low-pressure chamber and a high-pressure chamber, and a first liquid inlet and a first liquid outlet connected to the low-pressure chamber, and a second liquid inlet and a second liquid outlet connected to the high-pressure chamber are formed through the side wall of the piston cylinder, the first liquid inlet is connected to a liquid inlet pipe, a first one-way valve is arranged in the liquid inlet pipe, a conducting pipe is connected between the first liquid outlet and the second liquid inlet, a second one-way valve is arranged in the conducting pipe, the second liquid outlet is connected to the liquid outlet pipe, and a third one-way valve is arranged in the liquid outlet pipe;

[0008] a transmission shaft, a first end of which passes through the piston cylinder, is movably connected to the piston cylinder, and is fixedly connected to the piston in the high-pressure chamber;

[0009] A driving assembly is drivingly connected to the second end of the transmission shaft to drive the transmission shaft to reciprocate along the piston cylinder.

[0010] Optionally, the cross-sectional area of ​​the first end of the transmission shaft gradually increases in a direction toward the piston.

[0011] Optionally, the volume of the high-pressure chamber is set to 0.8-0.95 times the volume of the low-pressure chamber.

[0012] Optionally, the low-temperature liquid two-stage pressurization system further includes: a coaxial positioner, which is sleeved on the transmission shaft and fixedly connected to the piston cylinder.

[0013] Optionally, a first flange is installed at one end of the coaxial positioner away from the piston cylinder, and the first flange is sleeved on the transmission shaft.

[0014] Optionally, a second flange is mounted on one end of the piston cylinder away from the coaxial positioner.

[0015] Optionally, a first sealing member is provided between the transmission shaft and the piston cylinder.

[0016] Optionally, the driving assembly comprises:

[0017] A hydraulic cylinder, wherein a hydraulic chamber is provided in the hydraulic cylinder;

[0018] A hydraulic piston, the hydraulic piston is arranged in the hydraulic cavity, movably connected to the hydraulic cavity, and divides the hydraulic cavity into a first cavity and a second cavity, the side wall of the hydraulic cylinder is penetrated to open a first inlet and a first outlet connected to the first cavity, and a second inlet and a second outlet connected to the second cavity, the first inlet, the first outlet, the second inlet and the second outlet are respectively connected to a four-way reversing valve; the second end of the transmission shaft penetrates the hydraulic cylinder, is movably connected to the hydraulic cylinder, and is fixedly connected to the hydraulic piston;

[0019] A hydraulic pump, wherein an oil outlet of the hydraulic pump is connected to an oil inlet of the four-way reversing valve.

[0020] Optionally, a second seal is provided between the transmission shaft and the hydraulic cylinder.

[0021] The present invention also provides a low-temperature liquid two-stage boosting assembly, including a low-temperature liquid storage tank and the low-temperature liquid two-stage boosting system described in any of the above items, wherein the liquid inlet pipe of the low-temperature liquid two-stage boosting system is immersed in the low-temperature liquid storage tank.

[0022] Compared with the prior art, the above technical solution provided by the present invention has at least the following beneficial effects:

[0023] By adopting the present invention, a driving assembly is used to drive the piston to reciprocate in the piston chamber, so that the cryogenic liquid enters the high-pressure chamber for secondary pressurization after the initial pressurization in the low-pressure chamber, thereby achieving a higher pressurization effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of a low-temperature liquid two-stage pressurization system according to an embodiment of the present invention;

[0025] Figure 2 for Figure 1 A schematic diagram of a piston cylinder of a two-stage low-temperature liquid pressurization system is shown;

[0026] Figure 3 for Figure 1 Schematic diagram of the first one-way valve of the low-temperature liquid two-stage pressurization system shown.

[0027] Reference numerals:

[0028] 1: piston cylinder; 2: piston; 3: transmission shaft; 4: driving assembly; 401: hydraulic cylinder; 402: hydraulic piston; 403: first cavity; 404: second cavity; 405: first inlet; 406: first outlet; 407: second inlet; 408: second outlet; 5: low-pressure cavity; 6: high-pressure cavity; 7: liquid inlet pipe; 8: conducting pipe; 9: liquid outlet pipe; 10: coaxial positioner; 11: first flange; 12: second flange; 13: first sealing member; 14: second sealing member. DETAILED DESCRIPTION

[0029] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only simplified descriptions for the convenience of describing the present invention, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0030] Figure 1 A schematic diagram of a low-temperature liquid two-stage pressurization system according to an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of a piston cylinder of a two-stage low-temperature liquid pressurization system is shown; Figure 3 for Figure 1 Schematic diagram of the first one-way valve of the low-temperature liquid two-stage pressurization system shown.

[0031] like Figure 1-Figure 3 As shown, the low-temperature liquid two-stage boosting system includes a piston cylinder 1, a piston 2, a transmission shaft 3 and a drive assembly 4.

[0032] A piston chamber is provided in the piston cylinder 1; the piston 2 is provided in the piston chamber, movably connected to the piston chamber, and divides the piston chamber into a low-pressure chamber 5 and a high-pressure chamber 6. The side wall of the piston cylinder 1 is penetrated by a first liquid inlet and a first liquid outlet connected to the low-pressure chamber 5, and a second liquid inlet and a second liquid outlet connected to the high-pressure chamber 6. The first liquid inlet is connected to a liquid inlet pipe 7, and a first one-way valve is provided in the liquid inlet pipe 7. A conducting pipe 8 is connected between the first liquid outlet and the second liquid inlet, and a second one-way valve is provided in the conducting pipe 8. The second liquid outlet is connected to a liquid outlet pipe 9, and a third one-way valve is provided in the liquid outlet pipe 9; the first end of the transmission shaft 3 penetrates the piston cylinder 1, is movably connected to the piston cylinder 1, and is fixedly connected to the piston 2 in the high-pressure chamber 6; the driving assembly 4 is drivingly connected to the second end of the transmission shaft 3 to drive the transmission shaft 3 to reciprocate along the piston cylinder 1.

[0033] like Figure 1As shown, the piston chamber is located above the piston 2 as the high-pressure chamber 6, and the piston chamber is located below the piston 2 as the low-pressure chamber 5. When the system is working, the liquid inlet pipe 7 is connected to the cryogenic liquid, the drive assembly 4 is started, and the drive assembly 4 drives the transmission shaft 3 to move downward, thereby driving the piston 2 connected to the transmission shaft 3 to move toward the low-pressure chamber 5. At this time, the first one-way valve in the liquid inlet pipe 7 is closed, and the cryogenic liquid in the low-pressure chamber 5 is initially compressed and pressurized. When the cryogenic liquid in the low-pressure chamber 5 is compressed to a set pressure, such as 1-45MPa, the second one-way valve in the conducting pipe 8 is opened, and the initially pressurized cryogenic liquid flows into the high-pressure chamber 6 through the conducting pipe 8. After the high-pressure chamber 6 is filled, the drive assembly 4 is driven in reverse to drive the transmission shaft 3 to move upward, thereby driving the piston 2 connected to the transmission shaft 3 to move toward the high-pressure chamber 6. At this time, the second one-way valve is closed to prevent the cryogenic liquid from flowing back. The cryogenic liquid in the high-pressure chamber 6 is compressed and pressurized for the second time. When the cryogenic liquid in the high-pressure chamber 6 is compressed to a set pressure, such as 70-90 MPa, the third one-way valve in the liquid outlet pipe 9 is opened, and the secondary pressurized cryogenic liquid in the high-pressure chamber 6 is transported to the external system, such as to the vaporizer, through the liquid outlet pipe 9. During the movement of the piston 2 toward the high-pressure chamber 6, the first one-way valve is opened, and the cryogenic liquid is supplemented to flow into the low-pressure chamber 5 through the liquid inlet pipe 7. When a certain amount of the secondary pressurized cryogenic liquid in the high-pressure chamber 6 is discharged, the drive assembly 4 is driven in reverse again to drive the transmission shaft 3 to move downward, thereby driving the piston 2 connected to the transmission shaft 3 to move toward the low-pressure chamber 5, and the cycle repeats.

[0034] By adopting the low-temperature liquid two-stage boosting system of the present invention, the driving assembly 4 is used to drive the piston 2 to reciprocate in the piston chamber, so that the low-temperature liquid enters the high-pressure chamber 6 for secondary boosting after the initial boosting in the low-pressure chamber 5, thereby achieving a higher boosting effect.

[0035] like Figure 1 , Figure 2As shown, in this embodiment, the lower end of the transmission shaft 3 passes through the piston cylinder 1 and is fixedly connected to the upper end of the piston 2. The piston 2 divides the piston chamber into the upper high-pressure chamber 6 and the lower low-pressure chamber 5. The first liquid inlet passes through the right side wall of the bottom end of the piston cylinder 1, the first liquid outlet passes through the left side wall of the bottom end of the piston cylinder 1, the second liquid inlet passes through the left side wall of the top end of the piston cylinder 1, and the second liquid outlet passes through the right side wall of the top end of the piston cylinder 1. The driving component 4 is connected to the upper end of the transmission shaft 3 and drives the transmission shaft 3 to reciprocate up and down along the extension direction of the piston cylinder 1. According to actual application conditions, the driving component 4 can adopt any driving form, as long as it can drive the transmission shaft 3 to reciprocate up and down along the extension direction of the piston cylinder 1. The first one-way valve, the second one-way valve and the third one-way valve can adopt Figure 3 The one-way valve structure shown in the figure may also adopt any one-way valve structure, as long as when the low-pressure chamber 5 is in a pressurized state, the first one-way valve and the third one-way valve are closed, and the second one-way valve is opened when the low-pressure chamber 5 is pressurized to a set pressure, so that the low-temperature liquid after the initial pressurization can smoothly enter the high-pressure chamber 6, and when the high-pressure chamber 6 is in a pressurized state, the first one-way valve is opened, the second one-way valve is closed, and the third one-way valve is opened when the high-pressure chamber 6 is pressurized to a set pressure, so that the low-temperature liquid after the secondary pressurization can be smoothly discharged to the external system, and new low-temperature liquid can be smoothly added to the low-pressure chamber 5.

[0036] The cryogenic liquid may be LH2, LNG, LCO2, LN2, etc., which is stored in a liquid storage tank in an insulated cryogenic space, and the liquid inlet pipe 7 is immersed in the cryogenic liquid.

[0037] When the piston 2 moves downward, the cryogenic liquid in the low-pressure chamber 5 is initially pressurized. At this time, the required diameter of the transmission shaft 3 is calculated as follows:

[0038]

[0039] Where, d1---the minimum diameter required for the transmission shaft 3 when pressed down;

[0040] F1---Force acting on transmission shaft 3;

[0041] σ1---Permissible tension of transmission shaft 3 material;

[0042] Among them, Rm is the tensile strength of the material and n is the safety factor.

[0043] When the piston 2 moves upward, the cryogenic liquid in the high-pressure chamber 6 is pressurized for a second time. At this time, the required diameter of the transmission shaft 3 is calculated as follows:

[0044]

[0045] Where, d2---the minimum diameter required for the transmission shaft 3 when pulling up;

[0046] F2---Force on transmission shaft 3;

[0047] σ2---Permissible pressure of transmission shaft 3 material;

[0048] Among them, σ bc is the compressive strength of the material and n is the safety factor.

[0049] Taking 304 stainless steel as an example, when d1=d2, F2>5F1. This result shows that the boosting capacity of the existing primary boosting system can be increased by more than 5 times by using the cryogenic liquid two-stage boosting system to perform secondary compression and boosting on the cryogenic liquid.

[0050] Optionally, the cross-sectional area of ​​the first end of the transmission shaft 3 gradually increases in the direction toward the piston 2. This arrangement can enhance the connection strength between the transmission shaft 3 and the piston 2, while reducing the volume of the high-pressure chamber 6 and reducing the release of liquid pressure.

[0051] Since the compression ratio of the liquid is almost zero, when the volume of the high-pressure chamber 6 is greater than or equal to the volume of the low-pressure chamber 5, the liquid pressure will be released. Therefore, the volume of the high-pressure chamber 6 should be appropriately reduced. Figure 1 , Figure 2 As shown, in this embodiment, the high-pressure chamber 6 is located at the upper part of the piston 2. The cross-sectional area of ​​the lower end of the transmission shaft 3 gradually increases downward within a certain length range near the end, and the whole is conical. The cross-sectional diameter of the lowermost end is the same as the diameter of the cross-sectional area of ​​the piston 2. While increasing the contact area with the piston 2 and improving the connection strength between the two, it occupies the space in the high-pressure chamber 6 and reduces the volume of the high-pressure chamber 6.

[0052] Optionally, the volume of the high-pressure chamber 6 is set to 0.8-0.95 times the volume of the low-pressure chamber 5. This setting makes the volume of the high-pressure chamber 6 large enough to ensure the efficiency of the secondary pressurization of the cryogenic liquid. At the same time, the volume of the high-pressure chamber 6 is small enough to reduce the release of liquid pressure and ensure the smooth progress of the secondary pressurization process. At the same time, since the volume of the low-pressure chamber 5 is higher than that of the high-pressure chamber 6, a small amount of cryogenic liquid will be stored in the low-pressure chamber 5, which avoids the hard contact between the piston 2 and the bottom of the piston cylinder 1, and realizes the role of piston steering positioning.

[0053] Optionally, the low-temperature liquid two-stage boosting system further includes a coaxial positioner 10, which is sleeved on the transmission shaft 3 and fixedly connected to the piston cylinder 1. This arrangement improves the stability of the transmission shaft 3 during movement.

[0054] like Figure 1 As shown, in this embodiment, the coaxial positioner 10 is a hollow cylinder, the inner wall diameter of which matches the outer wall diameter of the transmission shaft 3, and the transmission shaft 3 is inserted into the coaxial positioner 10, and the two are clearance-matched, so that the transmission shaft 3 can both reciprocate along the coaxial positioner 10 and be limited by the coaxial positioner 10 without excessive lateral displacement. The lower end of the coaxial positioner 10 is fixedly connected to the top end of the piston cylinder 1.

[0055] Optionally, a first flange 11 is installed at one end of the coaxial positioner 10 away from the piston cylinder 1, and the first flange 11 is sleeved with the transmission shaft 3. This arrangement facilitates fixing the system to other structural parts with the help of the first flange 11.

[0056] like Figure 1 As shown, in this embodiment, the first flange 11 is fixed to the upper end of the coaxial positioner 10, and the transmission shaft 3 passes through the first flange 11 and the coaxial positioner 10 in sequence and can move up and down along the two. When the system needs to be fixed on other structural parts, such as fixed in a cryogenic liquid storage tank, the connection can be achieved with the help of the preset first flange 11.

[0057] Optionally, a second flange 12 is installed at one end of the piston cylinder 1 away from the coaxial positioner 10. This arrangement can cooperate with the first flange 11 to fix the system more stably on other structural parts.

[0058] like Figure 1 As shown, in this embodiment, the lower end of the piston cylinder 1 is connected to the second flange 12. When the system needs to be fixed in a cryogenic liquid storage tank, the connection with the cryogenic liquid storage tank can be achieved with the help of the preset first flange 11 and the second flange 12.

[0059] Optionally, a first sealing member 13 is provided between the transmission shaft 3 and the piston cylinder 1. This arrangement seals the connection between the transmission shaft 3 and the piston cylinder 1 to prevent the pressure from being released and the cryogenic liquid from flowing out.

[0060] like Figure 1 As shown, in this embodiment, the first sealing member 13 is sleeved on the circumference of the transmission shaft 3 to block the gap between the circumference of the transmission shaft 3 and the piston cylinder 1, but does not affect the up and down reciprocating movement of the transmission shaft 3.

[0061] Optionally, the drive assembly 4 includes a hydraulic cylinder 401, a hydraulic piston 402 and a hydraulic pump (not shown). A hydraulic chamber is provided in the hydraulic cylinder 401; the hydraulic piston 402 is provided in the hydraulic chamber, movably connected to the hydraulic chamber, and divides the hydraulic chamber into a first chamber 403 and a second chamber 404; the side wall of the hydraulic cylinder 401 is provided with a first inlet 405 and a first outlet 406 connected to the first chamber 403, and a second inlet 407 and a second outlet 408 connected to the second chamber 404; the first inlet 405, the first outlet 406, the second inlet 407 and the second outlet 408 are respectively connected to a four-way reversing valve (not shown); the second end of the transmission shaft 3 passes through the hydraulic cylinder 401, is movably connected to the hydraulic cylinder 401, and is fixedly connected to the hydraulic piston 402; the oil outlet of the hydraulic pump is connected to the oil inlet of the four-way reversing valve. The hydraulic drive is adopted, which is simple to operate, stable in operation, small inverting impact, and convenient for realizing frequent reversing.

[0062] like Figure 1As shown, in this embodiment, the hydraulic cylinder 401 is fixed to the upper end of the first flange 11, and the hydraulic cylinder 401, the first flange 11, the coaxial positioner 10 and the piston cylinder 1 are coaxially arranged. Taking the first cavity 403 located above the hydraulic piston 402 in the hydraulic cavity and the second cavity 404 located below the hydraulic piston 402 as an example, the upper end of the transmission shaft 3 passes through the hydraulic cylinder 401 and is fixedly connected to the hydraulic piston 402 in the second cavity 404. The first inlet 405 is opened at the top right wall of the hydraulic cylinder 401, the first outlet 406 is opened at the top left wall of the hydraulic cylinder 401, the second inlet 407 is opened at the lower right wall of the hydraulic cylinder 401, and the second outlet 408 is opened at the lower left wall of the hydraulic cylinder 401. The hydraulic pump is started to make the hydraulic oil flow into the first cavity 403 through the hydraulic pump, the four-way reversing valve and the first inlet 405, and pressure is applied to the upper surface of the hydraulic piston 402, so that the hydraulic piston 402 moves downward. At the same time, the hydraulic oil in the second cavity 404 below the hydraulic piston 402 is squeezed and discharged to the external hydraulic oil circulation pipeline through the second outlet 408 and the four-way reversing valve. During the downward movement of the hydraulic piston 402, the transmission shaft 3 and the piston 2 directly or indirectly connected thereto are driven to move downward toward the low-pressure cavity 5, thereby realizing the initial compression and pressurization of the low-temperature liquid in the low-pressure cavity 5, and outputting the initially pressurized low-temperature liquid to the high-pressure cavity 6; the high-pressure cavity 6 is filled, the four-way reversing valve is reversed, so that the hydraulic oil flows into the second cavity 404 through the hydraulic pump, the four-way reversing valve and the second inlet 407, and exerts pressure on the lower surface of the hydraulic piston 402, so that the hydraulic piston 402 moves upward. At the same time, the hydraulic oil in the first cavity 403 above the hydraulic piston 402 is squeezed and discharged to the external hydraulic oil circulation pipeline through the first outlet 406 and the four-way reversing valve. During the upward movement of the hydraulic piston 402, the transmission shaft 3 and the piston 2 directly or indirectly connected thereto are driven to move upward toward the high-pressure cavity 6, realizing the process of secondary compression and pressurization of the low-temperature liquid in the high-pressure cavity 6, and outputting the secondary pressurized low-temperature liquid to the external system. Using a four-way reversing valve to control the flow direction of the hydraulic oil in the corresponding hydraulic cylinder 401 so that the hydraulic piston 2 moves back and forth along the hydraulic cylinder 401 is a mature existing technology, and its specific structure and principle are not repeated here.

[0063] Optionally, a second sealing member 14 is provided between the transmission shaft 3 and the hydraulic cylinder 401. This arrangement seals the connection between the transmission shaft 3 and the hydraulic cylinder 401 to prevent the pressure from being released and the hydraulic oil from flowing out.

[0064] like Figure 1 As shown, in this embodiment, the coaxial positioner 10 is sleeved on the transmission shaft 3, the first flange 11 is sleeved on the transmission shaft 3 and fixed above the coaxial positioner 10, the hydraulic cylinder 401 is fixed above the first flange 11, and the second sealing member 14 is sleeved on the circumference of the transmission shaft 3 to block the gap between the circumference of the transmission shaft 3 and the hydraulic cylinder 401, and extends along the transmission shaft 3 toward the first flange 11 and the coaxial positioner 10, while blocking the gap between the transmission shaft 3 and the first flange 11 and the coaxial positioner 10, but does not affect the up and down reciprocating movement of the transmission shaft 3. According to the actual application, the specific shape of the second sealing member 14 can be adjusted.

[0065] The present invention also provides a low-temperature liquid two-stage boosting assembly, including a low-temperature liquid storage tank, and also includes the low-temperature liquid two-stage boosting system described in any of the above embodiments, and the liquid inlet pipe 7 of the low-temperature liquid two-stage boosting system is immersed in the low-temperature liquid storage tank.

[0066] By adopting the low-temperature liquid two-stage boosting assembly of the present invention, the driving component 4 is used to drive the piston 2 to reciprocate in the piston chamber, so that the low-temperature liquid enters the high-pressure chamber 6 for secondary boosting after the initial boosting in the low-pressure chamber 5, thereby achieving a higher boosting effect.

[0067] The piston cylinder 1 of the low-temperature liquid two-stage boosting system can be fixedly connected to the inner wall of the low-temperature liquid storage tank and immersed in the low-temperature liquid storage tank as a whole, with only the driving component 4 arranged outside.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A two-stage low-temperature liquid pressurization system, characterized in that: include: A piston cylinder, wherein a piston chamber is provided in the piston cylinder; A piston, wherein the piston is arranged in the piston chamber, movably connected to the piston chamber, and divides the piston chamber into a low-pressure chamber and a high-pressure chamber, and a first liquid inlet and a first liquid outlet connected to the low-pressure chamber, and a second liquid inlet and a second liquid outlet connected to the high-pressure chamber are formed through the side wall of the piston cylinder, the first liquid inlet is connected to a liquid inlet pipe, a first one-way valve is arranged in the liquid inlet pipe, a conducting pipe is connected between the first liquid outlet and the second liquid inlet, a second one-way valve is arranged in the conducting pipe, the second liquid outlet is connected to the liquid outlet pipe, and a third one-way valve is arranged in the liquid outlet pipe; a transmission shaft, a first end of which passes through the piston cylinder, is movably connected to the piston cylinder, and is fixedly connected to the piston in the high-pressure chamber; A driving assembly is drivingly connected to the second end of the transmission shaft to drive the transmission shaft to reciprocate along the piston cylinder.

2. The cryogenic liquid two-stage pressurization system according to claim 1, characterized in that: The cross-sectional area of ​​the first end of the transmission shaft gradually increases in a direction toward the piston.

3. The cryogenic liquid two-stage pressurization system according to claim 1 or 2, characterized in that: The volume of the high-pressure chamber is set to 0.8-0.95 times the volume of the low-pressure chamber.

4. The cryogenic liquid two-stage pressurization system according to claim 1 or 2, characterized in that: Also includes: A coaxial positioner is sleeved on the transmission shaft and fixedly connected to the piston cylinder.

5. The cryogenic liquid two-stage pressurization system according to claim 4, characterized in that: A first flange is installed at one end of the coaxial positioner away from the piston cylinder, and the first flange is sleeved with the transmission shaft.

6. The cryogenic liquid two-stage pressurization system according to claim 5, characterized in that: A second flange is installed at one end of the piston cylinder away from the coaxial positioner.

7. The cryogenic liquid two-stage pressurization system according to claim 1 or 2, characterized in that: A first sealing member is provided between the transmission shaft and the piston cylinder.

8. The cryogenic liquid two-stage pressurization system according to claim 1 or 2, characterized in that: The drive assembly comprises: A hydraulic cylinder, wherein a hydraulic chamber is provided in the hydraulic cylinder; A hydraulic piston, the hydraulic piston is arranged in the hydraulic cavity, movably connected to the hydraulic cavity, and divides the hydraulic cavity into a first cavity and a second cavity, the side wall of the hydraulic cylinder is penetrated to open a first inlet and a first outlet connected to the first cavity, and a second inlet and a second outlet connected to the second cavity, the first inlet, the first outlet, the second inlet and the second outlet are respectively connected to a four-way reversing valve; the second end of the transmission shaft penetrates the hydraulic cylinder, is movably connected to the hydraulic cylinder, and is fixedly connected to the hydraulic piston; A hydraulic pump, wherein an oil outlet of the hydraulic pump is connected to an oil inlet of the four-way reversing valve.

9. The cryogenic liquid two-stage pressurization system according to claim 8, characterized in that: A second sealing member is provided between the transmission shaft and the hydraulic cylinder.

10. A cryogenic liquid two-stage booster assembly, comprising a cryogenic liquid storage tank, characterized in that: It also includes the low-temperature liquid two-stage pressurization system according to any one of claims 1 to 9, wherein the liquid inlet pipe of the low-temperature liquid two-stage pressurization system is immersed in the low-temperature liquid storage tank.

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