CN115388250A

CN115388250A - Low-temperature joint

Info

Publication number: CN115388250A
Application number: CN202110567275.3A
Authority: CN
Inventors: 杨少柒; 潘薇; 谢秀娟; 薛瑞; 龚领会
Original assignee: Technical Institute of Physics and Chemistry of CAS
Current assignee: Technical Institute of Physics and Chemistry of CAS
Priority date: 2021-05-24
Filing date: 2021-05-24
Publication date: 2022-11-25

Abstract

The invention is suitable for the field of liquid hydrogen conveying, and discloses a low-temperature joint which comprises a heat insulation pipe, a core body and a fastener, wherein the heat insulation pipe comprises a first component and a second component which have the same structure, the first component comprises a first inner pipe, a first outer pipe and a flange arranged at one end of the first component, the flange extends outwards from the first inner pipe and protrudes out of the first outer pipe, the core body comprises two guide blocks, a sealing block, a second inner pipe and a second outer pipe, the two guide blocks are correspondingly arranged at the tail ends of the two sides of the second outer pipe one by one, the sealing block is annularly arranged at the periphery of the second outer pipe, a second vacuum cavity is formed between the second inner pipe and the second outer pipe, core body end sockets for sealing the second vacuum cavity are arranged at the tail ends of the two sides of the second inner pipe, the core body is assembled in the heat insulation pipe, the flange of the first component of the heat insulation pipe and the flange of the second component are clamped at the two sides of the sealing block, the first component and the second component are connected through the fastener, and the low-temperature joint can realize the quick connection and the low-leakage heat and low-loss liquid hydrogen conveying of a liquid hydrogen conveying pipeline.

Description

Low-temperature joint

Technical Field

The invention relates to the field of liquid hydrogen conveying, in particular to a low-temperature joint.

Background

Liquid hydrogen is one of the important forms of hydrogen energy utilization. The liquid hydrogen refueling station is a facility for effectively utilizing liquid hydrogen and can provide fuel for a hydrogen fuel automobile. In a mature process abroad, gaseous hydrogen is generally reduced to 20K for liquefaction in a liquid hydrogen plant, is conveyed to a liquid hydrogen tanker through a cryogenic transfer pipeline, is then conveyed to a hydrogenation station through the liquid hydrogen tanker, and is conveyed to a liquid hydrogen storage tank in the station through the cryogenic transfer pipeline again for storage. The saturated liquid hydrogen temperature under atmospheric pressure is 20.23K (-252.92 deg.C), which is far lower than normal temperature, and belongs to low temperature fluid, and the transportation, storage and transportation process must be insulated and heat preserved to reduce loss.

The low-temperature joint is indispensable equipment for transmitting liquid hydrogen between different equipment, and the disassembly convenience and the low heat leakage performance of the low-temperature joint are the keys for reducing the disassembly loss of the liquid hydrogen when the disassembly is time-consuming. Currently available cryogenic joints include flanged direct connection forms and BNC joint forms. In the flange direct connection type low-temperature joint, the flange is directly contacted with the low-temperature fluid, so that heat leakage is very large, and the joint is seriously frosted. The low temperature joint in the BNC joint form can reduce heat leakage, but the two ends of the infusion tube need to be welded with the male and female heads of the BNC joint, the structure is complex, and the installation is special.

Disclosure of Invention

The invention aims to provide a low-temperature joint which is convenient and quick to disassemble and can realize quick connection of a liquid hydrogen transmission pipeline and low-heat-leakage and low-loss liquid hydrogen transmission.

In order to achieve the purpose, the invention provides the following scheme:

a low-temperature joint comprises a heat insulation pipe, a core body and a fastener, wherein the heat insulation pipe comprises a first component and a second component, the first component comprises a first inner pipe and a first outer pipe which are coaxially arranged and a flange arranged at one end of the first component, the flange extends outwards from the first inner pipe and protrudes out of the first outer pipe, the structure of the second component is the same as that of the first component, the core body comprises two guide blocks, a sealing block and a second inner pipe and a second outer pipe which are coaxially arranged, the two guide blocks are arranged at the two side ends of the second outer pipe in a one-to-one correspondence mode, the sealing block is annularly arranged on the periphery of the second outer pipe, a second vacuum cavity is formed between the second inner pipe and the second outer pipe, core body sealing heads extending from the second inner pipe to the guide blocks are arranged at the two side ends of the second inner pipe, the core body sealing heads are used for closing the second vacuum cavity, the core body is assembled in the heat insulation pipe, the flange of the first component and the flange of the second component are clamped at the two sides of the sealing block, the first component and the flange of the first component is connected with the second component through the sealing block.

Preferably, the sealing block and the flange of the first component and the sealing block and the flange of the second component are sealed through an inner sealing ring and an outer sealing ring, two sealing grooves are formed in the side face, in contact with the flange, of the sealing block, the inner sealing ring is installed on one of the sealing rings, and the outer sealing ring is installed on the other sealing ring.

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

Preferably, the side wall of the first inner pipe opposite to the first outer pipe is wrapped with an insulating wrapping layer.

Preferably, the flanges are welded integrally with the first inner pipe and the first outer pipe, respectively.

Preferably, the sealing block, the second inner pipe, the second outer pipe and the core body end socket are welded into a whole.

Preferably, step positions are arranged at the tail ends of the two sides of the second outer pipe, and the two guide blocks are installed on the step positions in a one-to-one correspondence mode.

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

Preferably, the side wall of the second inner pipe opposite to the second outer pipe is wrapped with an insulating wrapping layer.

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

The low-temperature joint provided by the invention has the advantages that during assembly, the assembled core body is inserted into the first component of the heat insulation pipe, and under the guide of the guide block, the core body is inserted into the first component approximately concentrically until the sealing block contacts the flange; and then, sleeving a second part of the heat insulation pipe into the other side of the core body, under the guide of the guide block, enabling flanges of the second part to be in contact with the other side of the sealing block, and finally locking the flanges at two sides by using a fastening piece to complete the assembly of the low-temperature joint, wherein the assembly is convenient and fast, the disassembly is convenient, and the quick connection of the liquid hydrogen transmission pipeline can be realized. In addition, the heat insulation pipe and the core body of the low-temperature joint both adopt double-layer pipe bodies, so that the low-temperature joint has excellent heat insulation performance and can realize low-heat-leakage and low-loss liquid hydrogen transportation. In addition, the cryogenic coupling of the present invention is provided with the guide blocks at both side ends of the second outer pipe to allow the core bodies to be inserted approximately concentrically into the first member and the second member of the thermal insulation pipe, thereby improving the assembly accuracy.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic structural view of a cryogenic joint according to a first embodiment of the present invention;

FIG. 2 is a schematic structural view of a cryogenic joint according to a second embodiment of the present invention;

FIG. 3 is a schematic structural view of a cryogenic joint according to a third embodiment of the present invention;

fig. 4 is a schematic structural view of a cryogenic joint according to a fourth embodiment of the present invention.

The reference numbers illustrate:

1. a heat-insulating pipe; 11. a flange; 12. a first outer tube; 13. a first inner tube; 14. a first vacuum chamber; 15. a heat-insulating bundling layer;

2. a core body; 21. a guide block; 22. a second outer tube; 23. an inner seal ring; 24. an outer sealing ring; 25. a sealing block; 26. sealing a core body end; 27. a second inner tube; 28. a second vacuum chamber; 29. a gap;

3. a fastener.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.

It should be noted that all directional indicators (such as up, down, left, right, front, and back \8230;) in the embodiments of the present invention are only used to explain the relative positional relationship between the components, the motion situation, etc. in a specific posture (as shown in the attached drawings), and if the specific posture is changed, the directional indicators are changed accordingly.

It will also be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

In addition, the descriptions relating to "first", "second", etc. in the present invention are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

As shown in fig. 1 to 4, a cryogenic joint according to an embodiment of the present invention can achieve low heat leakage and low loss liquid hydrogen transport.

Referring to fig. 1 to 4, a cryogenic coupling according to an embodiment of the present invention includes a thermal insulation pipe 1, a core 2 and a fastener 3, the thermal insulation pipe 1 is a double-layered thermal insulation pipe including a first member and a second member, the first member includes a first inner pipe 13 and a first outer pipe 12 coaxially disposed, and a flange 11 disposed at one end of the first member, the flange 11 extends outward from the first inner pipe 13 and protrudes out of the first outer pipe 12, that is, the flange 11 is an annular structure capable of connecting the first inner pipe 13 and the first outer pipe 12 into a whole, the second member has a structure identical to that of the first member, the core 2 includes two guide blocks 21, a sealing block 25, and a second inner pipe 27 and a second outer pipe 22 coaxially disposed, the two guide blocks 21 are installed at ends of both sides of the second outer pipe 22 one by one to one, the sealing block 25 is annularly disposed at an outer periphery of the second outer pipe 22, a second vacuum chamber 28 is formed between the second inner pipe 27 and the second outer pipe 22, a gap of the second vacuum chamber 28 is designed according to the design, ends of the second inner pipe 27 are provided with a second vacuum chamber 27 extending toward both sides of the second inner pipe 27, and a second vacuum chamber 28 is formed in the second vacuum chamber 28 for further reducing the effect of the second vacuum chamber 28 for reducing the effect of the thermal insulation pipe 26 for forming a heat-sealing head 26 for reducing the heat-sealing effect of the hydrogen-conducting core. The core body 2 is fitted in the thermal insulation piping 1, and the flange 11 of the first member and the flange 11 of the second member of the thermal insulation piping 1 are clamped on both sides of the sealing block 25, the first member and the second member are connected by the fastening member 3, and the sealing block 25 is sealingly connected with the flange 11 of the first member and the flange 11 of the second member, respectively.

It should be noted that, the first outer tube 12 and the first inner tube 13 may be made of a metal hard tube, such as stainless steel with poor thermal conductivity, or may be made of a part of a metal hose, that is, a joint is changed into a metal hose, or may be made of a whole metal hose, and the joint is lined with a metal hard tube. The outer diameter and the wall thickness of the first inner tube 13 are designed in accordance with the pressure and the flow rate. The diameter and wall thickness of the first outer tube 12 are selected based on the heat leak requirement per unit length, the thickness of the insulating wrap 15 and the clearance design of the second vacuum chamber 28. The flange 11 has its inside and outside diameter determined by the first outer pipe 12 and the first inner pipe 13, and the thickness and the number of bolt holes are checked according to the liquid hydrogen pressure.

Except for the core heads 26 at both ends, there is no contact between the second inner tube 27 and the second outer tube 22. The second inner pipe 27 is a metal hard pipe, such as a stainless steel pipe, the second outer pipe 22 is a metal hard pipe, the outer diameter of the metal hard pipe is matched with the first inner pipe 13 in the heat insulation pipe 1, a gap 29 of not less than 1mm is generally reserved, and the wall thickness meets the requirement of liquid hydrogen pressure, namely the thickness of the guide block 21 is larger than that of the second outer pipe 22. The guide block 21 is separated from the other parts of the core body 2, the inner diameter of the guide block is consistent with the outer diameter of the end socket of the second outer tube 22, the outer diameter of the guide block is consistent with the inner diameter of the second inner tube 27, the guide block 21 is made of polytetrafluoroethylene or other low-temperature materials, is arranged at the tail end of the second outer tube 22, and is provided with a through hole or a groove along the axial direction. The outer diameter of the sealing block 25 is matched with the flange 11, can be smaller than the minimum value of the distance between a bolt hole of the flange 11 and the center of the flange 11, and can also be consistent with the outer diameter of the flange 11, through holes with the same size are processed on the sealing block 25 for bolts to penetrate through, and the wall thickness of the sealing block 25 is determined by pressure checking.

It will be appreciated that the portion of the sealing block 25 projecting beyond the second outer tube 22 may be flush with the portion of the flange 11 projecting beyond the first outer tube 12 (as shown in figure 1), with the fastener 3 being secured through the flange 11 of the first part, the sealing block 25 and the flange 11 of the second part. There is a height difference between the sealing block 25 and the flange 11 (as shown in fig. 2), and the fastening member 3 is fixed after passing through the flange 11 of the first member and the flange 11 of the second member.

In the low-temperature joint provided by the embodiment of the invention, the assembled core body 2 is inserted into the first part of the heat insulation pipe 1 during assembly, and the core body 2 is approximately concentrically inserted into the first part under the guide of the guide block 21 until the sealing block 25 contacts the flange 11; and then, sleeving the second part of the heat insulation pipe 1 on the other side of the core body 2, under the guide of the guide block 21, enabling the flange 11 of the second part to be in contact with the other surface of the sealing block 25, and finally locking the flanges 11 at two sides by using the fastening piece 3 to complete the assembly of the low-temperature joint, wherein the assembly is convenient and fast, the disassembly is convenient, and the quick connection of a liquid hydrogen transmission pipeline can be realized. In addition, the double-layer pipe body is adopted as both the heat insulation pipe 1 and the core body 2 of the low-temperature joint, so that the heat insulation performance is excellent, and low heat leakage and low loss liquid hydrogen transportation can be realized. In addition, the cryogenic coupling according to the embodiment of the present invention is provided with the guide blocks 21 at both side ends of the second outer pipe 22 to approximately concentrically insert the core 2 into the first member and the second member of the thermal insulation piping 1, thereby making it possible to improve the assembly accuracy.

Optionally, the sealing block 25 and the flange 11 are sealed by a sealing ring, the number of the sealing rings may be set as required, and the installation manner of the sealing rings also needs to be set as required. As shown in fig. 1 and 2, two seal grooves are used between the single-side seal block 25 and the flange 11, two seal grooves are provided on the side surface of the seal block 25 contacting the flange 11 for installing the inner seal ring 23 and the outer seal ring 24, and the inner seal ring 23 and the outer seal ring 24 may be rubber O rings or other sealing gaskets. It is understood that the sealing groove may be provided on the sealing block 25 or on the flange 11, as shown in fig. 3, and two sealing grooves are provided on the flange 11. As shown in fig. 4, a sealing groove is used between the single-side sealing block 25 and the flange 11, and a sealing groove is provided on the side of the flange 11 contacting the sealing block 25 for installing a sealing ring, which may be a rubber O-ring or other sealing gasket.

Preferably, a first vacuum chamber 14 is formed between the first inner tube 13 and the first outer tube 12, and the cryogenic connector according to the embodiment of the present invention can reduce heat leakage from the first inner tube 13 to the first outer tube 12 by providing the first vacuum chamber 14.

Preferably, the side wall (outer surface) of the first inner pipe 13 opposite to the first outer pipe 12 is wrapped with a heat insulation wrapping layer 15, and the heat insulation wrapping layer 15 can further improve the heat insulation effect.

It will be appreciated that the outer surface of the first inner pipe section 13 may or may not be wrapped with insulation.

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.

Preferably, the second vacuum chamber 28 can be filled with a small amount of porous material such as activated carbon for absorbing heat.

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.

Preferably, the ends of the two sides of the second outer tube 27 are provided with step positions (not shown), and the two guide blocks 21 are correspondingly mounted on the step positions one by one, so that the mounting manner is simple and reliable.

Preferably, the side wall (outer surface) of the second inner pipe 27 opposite to the second outer pipe 22 is wrapped with the heat insulation wrapping layer 15, the outer surface of the heat insulation material is not in contact with the inner surface of the second outer pipe 22 during wrapping, and the heat insulation wrapping layer 15 is arranged to further improve the heat insulation effect.

It will be appreciated that the outer surface of the second inner pipe section 27 may or may not be wrapped with insulation.

The low-temperature joint provided by the embodiment of the invention has the advantages of large thermal resistance on the whole heat transfer path, small heat leakage and capability of effectively reducing the loss of liquid hydrogen.

The working principle of the low-temperature joint provided by the embodiment of the invention is as follows: the first vacuum chamber 14 and the second vacuum chamber 28 are evacuated to a predetermined vacuum and then sealed; after the guide blocks 21 are installed at both ends of the second outer tube 22 and the sealing rings are installed in the sealing grooves of the sealing blocks 25 (different installation methods of the sealing rings are applicable to different assembling methods, which are only exemplified herein), the assembled core body 2 is inserted into the first member of the thermal insulation tube 1, and the core body 2 is inserted approximately concentrically therein under the guide of the guide blocks 21 until the sealing blocks 25 contact the flange 11; then, the second member of the thermal insulation piping 1 is fitted into the other side of the core body 2, and the flange 11 of the second member is brought into contact with the other side of the sealing block 25 under the guide of the guide block 21; the flanges 11 on both sides are locked by the fasteners 3, and the sealing ring isolates the inside of the joint from the external environment. And pumping air in the joint in a vacuumizing mode, replacing the air with helium, and after the operation is carried out for a plurality of times, introducing liquid hydrogen to start conveying, wherein the oxygen content reaches the standard.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. The utility model provides a low-temperature joint, its characterized in that includes adiabatic pipe, core and fastener, adiabatic pipe includes first part and second part, first part includes coaxial setting's first inner tube and first outer tube, and set up the flange in the one end of first part, the flange is followed first inner tube outwards extends, and the protrusion first outer tube, the structure of second part with the structure of first part is the same, the core includes two guide blocks, seal block and coaxial setting's second inner tube and second outer tube, two the guide block one-to-one correspondence is installed on the both sides tip of second outer tube, the seal block encircles and is established in the second outer tube periphery, be formed with the second vacuum chamber between second inner tube and the second outer tube, the both sides tip of second inner tube all is provided with from the second inner tube to the core head that the guide block extends, the core head is used for sealing the second vacuum chamber, the core assembles in adiabatic pipe, and the flange of first part with the flange of second part presss from both sides the clamp block, first part and the second part passes through the seal block and the flange of second part is connected with the flange part respectively.

2. The cryogenic joint of claim 1, wherein the seal block and the flange of the first component and the seal block and the flange of the second component are sealed by an inner seal ring and an outer seal ring, two seal grooves are formed in the side face of the seal block, which is in contact with the flange, the inner seal ring is mounted on one of the seal rings, and the outer seal ring is mounted on the other seal ring.

3. The cryogenic joint of claim 1, wherein a first vacuum chamber is formed between the first inner tube and the first outer tube.

4. The cryogenic joint of claim 1, wherein a sidewall of the first inner pipe opposite the first outer pipe is wrapped with an insulating wrap.

5. The cryogenic joint of claim 1, wherein the flanges are welded integrally to the first inner pipe and the first outer pipe, respectively.

6. The cryogenic joint of claim 1, wherein the seal block, the second inner tube, the second outer tube, and the core head are welded together.

7. The cryogenic connector of claim 1, wherein the ends of the second outer pipe are provided with steps, and two of the guide blocks are mounted on the steps in a one-to-one correspondence.

8. The cryogenic connector of claim 1, wherein the guide block is an annular body made of polytetrafluoroethylene.

9. The cryogenic connector of claim 1, wherein the side wall of said second inner tube opposite said second outer tube is wrapped with an insulating wrap.

10. The cryogenic joint of claim 1, wherein the second vacuum chamber is filled with a porous material.