A low-temperature connector

Abstract

The present invention is applicable to the field of liquid hydrogen transportation, and discloses a cryogenic joint, which includes a heat-insulating pipe, a core body, and a fastener. The heat-insulating pipe includes a first component and a second component with the same structure. The first component includes a first inner pipe, a first outer pipe, and a flange provided at one end of the first component. The flange extends outward from the first inner pipe and protrudes from the first outer pipe. The core body includes two guiding blocks, a sealing block, a second inner pipe, and a second outer pipe. The two guiding blocks are respectively installed at the two ends on both sides of the second outer pipe. The sealing block is arranged around the outer circumference of the second outer pipe. A second vacuum chamber is formed between the second inner pipe and the second outer pipe. Core body end caps for closing the second vacuum chamber are provided at both ends of the second inner pipe. The core body is assembled inside the heat-insulating pipe. The flanges of the first component and the second component of the heat-insulating pipe are clamped on both sides of the sealing block. The first component and the second component are connected by a fastener. This cryogenic joint can achieve rapid connection of liquid hydrogen transmission pipelines and low heat leakage and low-loss liquid hydrogen transportation.

Description

Technical Field

[0001] The present invention relates to the field of liquid hydrogen transportation, and particularly to a cryogenic joint. Background Art

[0002] Liquid hydrogen is one of the important forms of hydrogen energy utilization. A liquid hydrogen refueling station is a facility for effectively utilizing liquid hydrogen and can provide fuel for hydrogen fuel vehicles. In mature foreign processes, gaseous hydrogen is usually liquefied to 20K at a liquid hydrogen plant, transported to a liquid hydrogen tanker through a cryogenic transmission pipeline, and then the liquid hydrogen is transported to the refueling station by the liquid hydrogen tanker and again transported to the in-station liquid hydrogen storage tank through a cryogenic transmission pipeline for storage. The saturated liquid hydrogen temperature under atmospheric pressure is 20.23K (-252.92°C), which is much lower than normal temperature and belongs to cryogenic fluid. During its transportation, storage and transportation processes, adiabatic heat insulation must be well done to reduce losses.

[0003] A cryogenic joint is an essential device for liquid hydrogen transmission between different devices. Its disassembly convenience and low heat leakage performance are the keys to reducing the disassembly and installation time and reducing liquid hydrogen disassembly and installation losses. Currently, available cryogenic joints include a flange direct connection form and a BNC joint form. For the cryogenic joint in the flange direct connection form, since the flange is directly in contact with the cryogenic fluid, the heat leakage is very large and the joint is severely frosted. The cryogenic joint in the BNC joint form can reduce heat leakage, but the male and female heads of the BNC joint need to be welded at both ends of the infusion pipe, with a complex structure and special installation. Summary of the Invention

[0004] The purpose of the present invention is to provide a cryogenic joint, which is convenient to disassemble and can achieve rapid connection of liquid hydrogen transmission pipelines and low heat leakage and low-loss liquid hydrogen transportation.

[0005] To achieve the above object, the solution provided by the present invention is:

[0006] A low-temperature joint, comprising a heat-insulating tube, a core body and a fastener. The heat-insulating tube includes a first component and a second component. The first component includes a first inner tube and a first outer tube arranged coaxially, and a flange provided at one end of the first component. The flange extends outward from the first inner tube and protrudes from the first outer tube. The structure of the second component is the same as that of the first component. The core body includes two guide blocks, a sealing block, and a second inner tube and a second outer tube arranged coaxially. The two guide blocks are respectively installed at both ends of the second outer tube, and the sealing block is arranged around the outer circumference of the second outer tube. A second vacuum chamber is formed between the second inner tube and the second outer tube. Core body end caps extending from the second inner tube to the guide blocks are provided at both ends of the second inner tube. The core body end caps are used to seal the second vacuum chamber. The core body is assembled in the heat-insulating tube, and the flanges of the first component and the second component are clamped on both sides of the sealing block. The first component and the second component are connected by the fastener, and the sealing block is respectively and sealingly connected to the flanges of the first component and the second component.

[0007] Preferably, the sealing block is sealed with the flange of the first component and the sealing block is sealed with the flange of the second component through an inner sealing ring and an outer sealing ring. Two sealing grooves are provided on the side surface of the sealing block in contact with the flange. The inner sealing ring is installed in one of the sealing rings, and the outer sealing ring is installed in the other sealing ring.

[0008] Preferably, a first vacuum chamber is formed between the first inner tube and the first outer tube.

[0009] Preferably, the side walls of the first inner tube opposite to the first outer tube are wrapped with a heat-insulating bandage layer.

[0010] Preferably, the flange is respectively welded to the first inner tube and the first outer tube as a whole.

[0011] Preferably, the sealing block, the second inner tube, the second outer tube and the core body end caps are welded as a whole.

[0012] Preferably, step positions are provided at both ends of the second outer tube, and the two guide blocks are respectively installed on the step positions.

[0013] Preferably, the guide block is an annular body made of polytetrafluoroethylene.

[0014] Preferably, the side walls of the second inner tube opposite to the second outer tube are wrapped with a heat-insulating bandage layer.

[0015] Preferably, the second vacuum chamber is filled with a porous material.

[0016] When the low-temperature joint provided by the present invention is assembled, the assembled core body is inserted into the first component of the heat-insulating pipe. Under the guidance of the guiding block, the core body is inserted into the first component approximately concentrically until the sealing block contacts the flange. Subsequently, the second component of the heat-insulating pipe is sleeved on the other side of the core body. Under the guidance of the guiding block, the flange of the second component contacts the other side of the sealing block. Finally, the two flanges are locked with fasteners to complete the assembly of the low-temperature joint. The assembly is convenient and easy to disassemble, and can realize the rapid connection of the liquid hydrogen transmission pipeline. Moreover, both the heat-insulating pipe and the core body of the low-temperature joint adopt double-layer pipe bodies, with excellent heat-insulating performance, and can realize low heat leakage and low-loss liquid hydrogen transportation. In addition, the low-temperature joint of the present invention is provided with guiding blocks at both ends of the second outer pipe to enable the core body to be inserted into the first component and the second component of the heat-insulating pipe approximately concentrically, thereby improving the assembly accuracy. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of 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 only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0018] Figure 1 It is a schematic structural diagram of the low-temperature joint according to the first embodiment of the present invention;

[0019] Figure 2 It is a schematic structural diagram of the low-temperature joint according to the second embodiment of the present invention;

[0020] Figure 3 It is a schematic structural diagram of the low-temperature joint according to the third embodiment of the present invention;

[0021] Figure 4 It is a schematic structural diagram of the low-temperature joint according to the fourth embodiment of the present invention.

[0022] Explanation of the Reference Numerals in the Drawings:

[0023] 1. Heat-insulating pipe; 11. Flange; 12. First outer pipe; 13. First inner pipe; 14. First vacuum chamber; 15. Heat-insulating wrapping layer;

[0024] 2. Core body; 21. Guiding block; 22. Second outer pipe; 23. Inner sealing ring; 24. Outer sealing ring; 25. Sealing block; 26. Core body head; 27. Second inner pipe; 28. Second vacuum chamber; 29. Gap;

[0025] 3. Fastener. Detailed Embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] It should be noted that all directional indications (such as up, down, left, right, front, back,...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0028] It should also be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0029] In addition, the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions appears to be contradictory or unable to be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0030] As Figures 1 to 4 shown, it is a low-temperature joint of an embodiment of the present invention, which can achieve low heat leakage and low-loss liquid hydrogen transportation.

[0031] Please refer to Figures 1-4, the low-temperature joint of the embodiment of the present invention includes a heat-insulating tube 1, a core body 2, and a fastener 3. The heat-insulating tube 1 is a double-layer heat-insulating tube, which includes a first component and a second component. The first component includes a first inner tube 13 and a first outer tube 12 arranged coaxially, and a flange 11 arranged at one end of the first component. The flange 11 extends outward from the first inner tube 13 and protrudes from the first outer tube 12. That is, the flange 11 is a ring structure, which can connect the first inner tube 13 and the first outer tube 12 into a whole. The structure of the second component is the same as that of the first component. The core body 2 includes two guiding blocks 21, a sealing block 25, and a second inner tube 27 and a second outer tube 22 arranged coaxially. The two guiding blocks 21 are respectively installed at both ends of the second outer tube 22. The sealing block 25 is arranged around the outer periphery of the second outer tube 22. A second vacuum chamber 28 is formed between the second inner tube 27 and the second outer tube 22. The gap of the second vacuum chamber 28 is determined according to the design. At both ends of the second inner tube 27, there are provided core head 26 extending from the second inner tube 27 to the guiding block 21. The core head 26 is used to seal the second vacuum chamber 28 and form a hydrogen gas column in the second vacuum chamber 28 to reduce the heat conduction performance of the second inner tube 27 and further improve the heat-insulating effect. The core body 2 is assembled in the heat-insulating tube 1, and the flange 11 of the first component and the flange 11 of the second component of the heat-insulating tube 1 are clamped on both sides of the sealing block 25. The first component and the second component are connected by the fastener 3, and the sealing block 25 is hermetically connected to the flange 11 of the first component and the flange 11 of the second component respectively.

[0032] It should be noted that the first outer tube 12 and the first inner tube 13 can both be made of metal hard tubes, such as stainless steel with poor heat conduction performance, or part of them can be made of metal flexible tubes, that is, the joint part is changed to a metal flexible tube, or all can be made of metal flexible tubes with a metal hard tube lining added at the joint. The outer diameter and wall thickness of the first inner tube 13 are designed according to the pressure and flow rate. The diameter and wall thickness of the first outer tube 12 are designed and selected according to the heat leakage per unit length requirement, the thickness of the heat-insulating wrapping layer 15, and the gap of the second vacuum chamber 28. The inner and outer diameters of the flange 11 are determined by the first outer tube 12 and the first inner tube 13, and the thickness and the number of bolt holes are checked according to the liquid hydrogen pressure.

[0033] Except for the core head 26 at both ends, there is no contact between the second inner tube 27 and the second outer tube 22. The second inner tube 27 is a rigid metal tube, such as a stainless steel tube. The second outer tube 22 is a rigid metal tube, whose outer diameter matches that of the first inner tube 13 in the heat-insulating tube 1, generally with a gap 29 of not less than 1 mm left. The wall thickness only needs to meet the liquid hydrogen pressure requirement, that is, the thickness of the guide block 21 is greater than the wall thickness of the second outer tube 22. The guide block 21 is separated from other parts of the core body 2. Its inner diameter is consistent with the outer diameter at the head of the second outer tube 22, and its outer diameter is consistent with the inner diameter of the second inner tube 27. The guide block 21 is made of polytetrafluoroethylene or other cryogenic materials and is installed at the end of the second outer tube 22, with through holes or grooves axially. The outer diameter of the sealing block 25 only needs to match the flange 11, and it can be smaller than the minimum distance from the bolt hole of the flange 11 to the center of the flange 11, or it can be the same as the outer diameter of the flange 11. Through holes of the same size are machined on the sealing block 25 for bolts to pass through. The wall thickness of the sealing block 25 is determined by pressure checking.

[0034] Understandably, the part of the sealing block 25 protruding from the second outer tube 22 can be flush with the part of the flange 11 protruding from the first outer tube 12 (as Figure 1 shown). At this time, the fastener 3 passes through the flange 11 of the first component, the sealing block 25 and the flange 11 of the second component and then is fixed. There is a height difference between the sealing block 25 and the flange 11 (as Figure 2 shown). At this time, the fastener 3 passes through the flange 11 of the first component and the flange 11 of the second component and then is fixed.

[0035] When assembling the cryogenic joint provided by the embodiment of the present invention, the assembled core body 2 is inserted into the first component of the heat-insulating tube 1. Under the guidance of the guide block 21, the core body 2 is inserted into the first component approximately concentrically until the sealing block 25 contacts the flange 11; subsequently, the second component of the heat-insulating tube 1 is sleeved on the other side of the core body 2. Under the guidance of the guide block 21, the flange 11 of the second component contacts the other side of the sealing block 25. Finally, the two flanges 11 are locked with the fastener 3 to complete the assembly of the cryogenic joint. The assembly is convenient and easy to disassemble, and can realize the rapid connection of the liquid hydrogen transmission pipeline. Moreover, both the heat-insulating tube 1 and the core body 2 of the cryogenic joint adopt double-layer tube bodies, with excellent heat-insulating performance, and can realize low heat leakage and low-loss liquid hydrogen transportation. In addition, the cryogenic joint of the embodiment of the present invention is provided with guide blocks 21 at both ends of the second outer tube 22 to make the core body 2 inserted into the first component and the second component of the heat-insulating tube 1 approximately concentrically, thereby improving the assembly accuracy.

[0036] Optionally, the sealing between the sealing block 25 and the flange 11 is through a sealing ring. The number of sealing rings can be set according to needs, and the installation method of the sealing rings also needs to be set according to needs. As Figure 1 and Figure 2As shown, two sealing grooves are adopted between the unilateral sealing block 25 and the flange 11. Two sealing grooves are provided on the side surface of the sealing block 25 in contact with the flange 11 for installing the inner sealing ring 23 and the outer sealing ring 24. The inner sealing ring 23 and the outer sealing ring 24 can be rubber O-rings or other sealing gaskets. It can be understood that the sealing grooves can be provided on the sealing block 25 or on the flange 11, such as Figure 3 as shown, the two sealing grooves are provided on the flange 11. Such as Figure 4 as shown, one sealing groove is adopted between the unilateral sealing block 25 and the flange 11. One sealing groove is provided on the side surface of the flange 11 in contact with the sealing block 25 for installing the sealing ring. The sealing ring can be a rubber O-ring or other sealing gaskets.

[0037] Preferably, a first vacuum chamber 14 is formed between the first inner pipe 13 and the first outer pipe 12. By setting the first vacuum chamber 14, the low-temperature joint of the embodiment of the present invention can reduce the heat leakage from the first inner pipe 13 to the first outer pipe 12.

[0038] Preferably, the side wall (outer surface) of the first inner pipe 13 opposite to the first outer pipe 12 is wrapped with an adiabatic wrapping layer 15. The setting of the adiabatic wrapping layer 15 can further improve the adiabatic effect.

[0039] It can be understood that the outer surface of the first inner pipe 13 can be wrapped with adiabatic materials or not.

[0040] Optionally, the flange 11 is welded to the first inner pipe 13 and the first outer pipe 12 respectively to further improve the sealing performance and reduce heat leakage.

[0041] Preferably, a small amount of porous materials such as activated carbon can be filled in the second vacuum chamber 28 for heat absorption.

[0042] Preferably, the sealing block 25, the second inner pipe 27, the second outer pipe 22 and the core head 26 are welded into a whole, which is beneficial to improving the assembly efficiency of the low-temperature joint.

[0043] Preferably, step positions (not shown in the figure) are provided at both ends of the second outer pipe 27. The two guide blocks 21 are respectively installed on the step positions, and the installation method is simple and reliable.

[0044] Preferably, the side wall (outer surface) of the second inner pipe 27 opposite to the second outer pipe 22 is wrapped with an adiabatic wrapping layer 15. When wrapping, the outer surface of the adiabatic material does not contact the inner surface of the second outer pipe 22. The setting of the adiabatic wrapping layer 15 can further improve the adiabatic effect.

[0045] It can be understood that the outer surface of the second inner pipe 27 can be wrapped with adiabatic materials or not.

[0046] In the cryogenic joint according to the embodiment of the present invention, the thermal resistance is large and the heat leakage is small throughout the entire heat transfer path, which can effectively reduce the loss of liquid hydrogen.

[0047] The working principle of the cryogenic joint according to the embodiment of the present invention is as follows: The first vacuum chamber 14 and the second vacuum chamber 28 are evacuated to a specified vacuum and then sealed; the guide blocks 21 are installed at both ends of the second outer tube 22. At the same time, after the sealing ring is installed in the sealing groove of the sealing block 25 (different installation methods of the sealing ring are applicable to different assembly methods, and this is only an example for illustration), the assembled core body 2 is inserted into the first component of the heat-insulating tube 1. Under the guidance of the guide blocks 21, the core body 2 is inserted approximately concentrically therein until the sealing block 25 contacts the flange 11; Subsequently, the second component of the heat-insulating tube 1 is sleeved on the other side of the core body 2. Under the guidance of the guide blocks 21, the flange 11 of the second component contacts the other side of the sealing block 25; The two flanges 11 are locked with the fasteners 3, and the sealing ring isolates the inside of the joint from the external environment. The air inside the joint is pumped out and replaced with helium in this way. After several times, when the oxygen content meets the standard, liquid hydrogen is introduced and the transportation starts.

[0048] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made by using the description and drawings of the present invention under the inventive concept of the present invention, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A low-temperature joint, characterized in that, It includes an adiabatic tube, a core body and fasteners. The adiabatic tube includes a first component and a second component. The first component includes a first inner tube and a first outer tube arranged coaxially, and a flange provided at one end of the first component. The flange extends outward from the first inner tube and protrudes from the first outer tube. The structure of the second component is the same as that of the first component. The core body includes two guiding blocks, a sealing block, and a second inner tube and a second outer tube arranged coaxially. The two guiding blocks are respectively mounted on the two ends of the second outer tube, and the sealing block is arranged around the periphery of the second outer tube. A second vacuum chamber is formed between the second inner tube and the second outer tube. At both ends of the second inner tube, there are provided core head seals extending from the second inner tube to the guiding blocks, and the core head seals are used to seal the second vacuum chamber. The core body is assembled in the adiabatic tube, and the flanges of the first component and the second component are clamped on both sides of the sealing block. The first component and the second component are connected by the fasteners, and the sealing block is hermetically connected to the flanges of the first component and the second component respectively; The guiding block is an annular body made of polytetrafluoroethylene; The second vacuum chamber is filled with a porous material.

2. The low-temperature joint according to claim 1, wherein, The sealing between the sealing block and the flange of the first component and between the sealing block and the flange of the second component is achieved by an inner sealing ring and an outer sealing ring. There are two sealing grooves on the side surface of the sealing block in contact with the flange. The inner sealing ring is installed in one of the sealing grooves, and the outer sealing ring is installed in the other sealing groove.

3. The low-temperature joint according to claim 1, characterized in that, A first vacuum chamber is formed between the first inner tube and the first outer tube.

4. The low-temperature joint according to claim 1, wherein The side wall of the first inner tube opposite to the first outer tube is wrapped with an adiabatic dressing layer.

5. The low-temperature joint according to claim 1, wherein The flange is welded to the first inner tube and the first outer tube integrally.

6. The low-temperature joint according to claim 1, wherein The sealing block, the second inner tube, the second outer tube and the core head seal are welded integrally.

7. The low-temperature joint according to claim 1, wherein, At both ends of the second outer tube, there are provided step positions, and the two guiding blocks are respectively mounted on the step positions.

8. The low-temperature joint according to claim 1, wherein The side wall of the second inner tube opposite to the second outer tube is wrapped with an adiabatic dressing layer.

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