Low-temperature vacuum straight pipe self-adaptive to fluid pressure and preparation method of low-temperature vacuum straight pipe

Abstract

The invention relates to a low-temperature vacuum straight pipe self-adaptive to fluid pressure and a preparation method thereof.The vacuum straight pipe comprises an inner pipe and an outer pipe, the inner pipe is made of low-expansion alloy steel 4J36, the outer pipe is made of stainless steel, a left sealing piece and a right sealing piece are correspondingly welded between the left end and the right end of the outer pipe and the inner pipe, and a vacuumizing connector is welded to the outer pipe in a sealed mode; the left inner sleeve and the left outer sleeve are coaxially arranged in a sleeved mode, the left inner supporting ring is welded to the right ends of the left inner sleeve and the left outer sleeve in a sealed mode, the left end of the left inner sleeve is welded to the inner pipe in a sealed mode, and the left end of the left outer sleeve is welded to the outer pipe in a sealed mode through a left outer supporting ring. The right inner sleeve and the right outer sleeve are coaxially arranged in a sleeved mode, the right inner supporting ring is welded to the left ends of the right inner sleeve and the right outer sleeve in a sealed mode, the right end of the right inner sleeve is welded to the inner pipe in a sealed mode, and the right end of the right outer sleeve is welded to the outer pipe in a sealed mode through the right outer supporting ring. The preparation method has the advantages of simple process and convenience in operation.

Description

Technical Field

[0001] The invention relates to a vacuum tube, in particular to a low-temperature vacuum straight tube capable of adapting to fluid pressure, and a method for preparing the vacuum straight tube. Background Art

[0002] In the aerospace field, cryogenic vacuum tubes are an important component of cryogenic filling systems, which together with cryogenic stop valves, cryogenic regulating valves, etc., form cryogenic medium pipelines. The working medium filled or discharged in the cryogenic filling system is liquid hydrogen, liquid oxygen, liquid nitrogen, liquid methane and other cryogenic media. In order to solve the problem of pipeline flexibility (thermal expansion and contraction) caused by the temperature difference between the cryogenic medium and the ambient temperature and the change in ambient temperature, the field usually sets bellows compensators on the inner tubes of cryogenic vacuum equipment such as cryogenic vacuum tubes. Although this method can solve the problem of pipeline flexibility, its structure is relatively complex, the manufacturing difficulty is relatively high, the cost is relatively high, and it will generate a large load on the pipelines at both ends, requiring additional support structures. Summary of the invention

[0003] The purpose of the present invention is to provide a low-temperature vacuum straight tube with adaptive fluid pressure and a preparation method thereof. The vacuum straight tube has the advantages of simple structure, low cost, easy maintenance, high reliability and strong adaptability; the preparation method has the advantages of simple process, easy operation and high production efficiency.

[0004] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a low-temperature vacuum straight tube with adaptive fluid pressure, including an inner tube and an outer tube coaxially arranged, the inner tube is made of low-expansion alloy steel 4J36, the outer tube is made of stainless steel, and a left seal and a right seal made of stainless steel are correspondingly welded between the left and right ends of the outer tube and the inner tube, and a vacuum joint made of stainless steel is seal-welded on the outer tube, the left seal includes a left inner sleeve and a left outer sleeve coaxially arranged, and a left inner support ring seal-welded at the right ends of both, the left end of the left inner sleeve is seal-welded to the inner tube, and the left end of the left outer sleeve is seal-welded to the outer tube through the left outer support ring, the right seal includes a right inner sleeve and a right outer sleeve coaxially arranged, and a right inner support ring seal-welded to the left ends of both, the right end of the right inner sleeve is seal-welded to the inner tube, and the right end of the right outer sleeve is seal-welded to the outer tube through the right outer support ring.

[0005] Furthermore, the present invention provides a low-temperature vacuum straight tube with adaptive fluid pressure, wherein a vacuum adsorption box is welded on the inner tube, and an adsorbent is provided in the vacuum adsorption box.

[0006] Furthermore, the present invention provides a low-temperature vacuum straight tube with adaptive fluid pressure, wherein the vacuum adsorption box is provided with an adsorbent filling port and a matching plug, and the outer tube is provided with a filling operation hole corresponding to the adsorbent filling port and a matching sealing cover.

[0007] Furthermore, the present invention provides a low-temperature vacuum straight tube with adaptive fluid pressure, wherein the vacuum adsorption box includes two annular side plates welded on the inner tube and a cylindrical arc plate welded on the two annular side plates, and the cylindrical arc plate is provided with dispersed adsorption holes.

[0008] Furthermore, the present invention provides a low-temperature vacuum straight tube capable of adaptively adjusting fluid pressure, wherein the inner tube, the left outer sleeve and the right outer sleeve are respectively covered with a heat-insulating layer made of a heat-insulating material.

[0009] Furthermore, the present invention provides a low-temperature vacuum straight tube capable of adaptively adjusting fluid pressure, wherein the vacuum adsorption box is coated with an insulating layer made of insulating material.

[0010] Furthermore, the present invention provides a low-temperature vacuum straight tube capable of self-adapting to fluid pressure, wherein a support made of a low heat leakage material is fixed on the inner tube.

[0011] Furthermore, the present invention provides a low-temperature vacuum straight tube with adaptive fluid pressure, wherein the support member is sleeved on the inner tube, and retaining rings welded to the inner tube are provided on both sides of the support member.

[0012] Based on the same concept, the present invention also provides a method for preparing the above-mentioned low-temperature vacuum straight tube, comprising the following steps:

[0013] S1. Weld the vacuum adsorption box, the left seal and the right seal to the inner tube respectively, wherein the vacuum adsorption box is provided with an adsorbent filling port;

[0014] S2. After the inner tube, the left outer tube and the right outer tube are covered with an insulation layer by an insulation material, the left and right ends of the outer tube are welded to the left outer support ring and the right outer support ring respectively, wherein the outer tube is provided with a vacuum joint and a filling operation hole;

[0015] S3, filling the vacuum adsorption box with adsorbent through the filling operation hole and the adsorbent filling port, sealing the adsorbent filling port with a plug after the filling is completed, and sealing and welding the cover to the filling operation hole;

[0016] S4. Perform vacuuming operation through the vacuuming joint, and close the vacuuming joint after the vacuuming is completed.

[0017] Furthermore, the present invention provides a method for preparing a low-temperature vacuum straight tube, wherein in step S1, before welding the left sealing member and the right sealing member, an operation of installing a support member on the inner tube is performed, comprising the following steps:

[0018] S1-1, sleeve a support member and two retaining rings correspondingly located on both sides of the support member on the inner tube;

[0019] S1-2, make two retaining rings clamp the support and weld them to the inner tube respectively.

[0020] Compared with the prior art, the present invention provides a low-temperature vacuum straight tube with adaptive fluid pressure and a preparation method thereof, which has the following advantages: the present invention provides a coaxially sleeved inner tube and outer tube, so that the inner tube is made of low-expansion alloy steel 4J36 and the outer tube is made of stainless steel, a left seal and a right seal made of stainless steel are correspondingly welded between the left and right ends of the outer tube and the inner tube, and a vacuum joint made of stainless steel is seal-welded on the outer tube, wherein the left seal includes a coaxially sleeved left inner sleeve and a left outer sleeve and a left inner support ring seal-welded on the right ends of both, the left end of the left inner sleeve is seal-welded to the inner tube, and the left end of the left outer sleeve is seal-welded to the outer tube via the left outer support ring; the right seal includes a coaxially sleeved right inner sleeve and a right outer sleeve and a right inner support ring seal-welded to the left ends of both, the right end of the right inner sleeve is seal-welded to the inner tube, and the right end of the right outer sleeve is seal-welded to the outer tube via the right outer support ring. Thus, a cryogenic vacuum straight pipe with adaptive fluid pressure is formed. Compared with the existing cryogenic vacuum pipe with bellows compensator, the present invention makes the inner pipe made of low expansion alloy steel 4J36, and utilizes its low expansion coefficient to adapt to the thermal expansion and contraction caused by temperature difference without setting bellows compensator, which not only simplifies the structure, reduces the manufacturing difficulty and cost, but also does not generate a large load on the pipelines at both ends, and does not need to set up additional support structures. At the same time, the present invention improves the deformation capacity of both by setting the left seal and the right seal, and makes the left seal and the right seal adopt a circuitous structure, which can adapt to the impact of the fluid pressure on the inner pipe, and the left outer support ring of the left seal and the right outer support ring of the right seal can be used as a connecting seat for extending and expanding the cryogenic vacuum straight pipe. It only needs to be sealed and welded with the left outer support ring and the right outer support ring of the adjacent cryogenic vacuum straight pipe through the connecting pipe, so that multiple cryogenic vacuum straight pipes can be combined into a long-distance cryogenic vacuum pipeline in sequence, which improves the convenience of connection operation. In addition, the present invention improves corrosion resistance and prolongs service life by making the outer pipe, the left seal, the right seal and the vacuum joint made of stainless steel. The preparation method of the low-temperature vacuum straight tube provided by the present invention has the advantages of simple process, convenient operation and high production efficiency.

[0021] The following is a detailed description of a low-temperature vacuum straight tube with adaptive fluid pressure and a preparation method thereof according to the present invention in conjunction with the specific embodiments shown in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a low-temperature vacuum straight tube with adaptive fluid pressure according to the present invention;

[0023] Figure 2 for Figure 1 A partial enlarged view of position A in the middle;

[0024] Figure 3 for Figure 1 A partial enlarged view of position B in the middle;

[0025] Figure 4 for Figure 1 A partial enlarged view of the C position in the middle. DETAILED DESCRIPTION

[0026] First of all, it should be explained that the directional words such as up, down, left, right, front and back described in the present invention are only described according to the drawings for the convenience of understanding, and are not intended to limit the technical solution and the scope of protection of the present invention.

[0027] like Figures 1 to 4 The specific implementation of a low-temperature vacuum straight tube with adaptive fluid pressure of the present invention is shown, comprising an inner tube 1 and an outer tube 2 coaxially sleeved, wherein the inner tube 1 is made of low expansion alloy steel 4J36, and the outer tube 2 is made of stainless steel. A left seal 3 and a right seal 4 made of stainless steel are welded correspondingly between the left and right ends of the outer tube 2 and the inner tube 1 to form a vacuum chamber structure, and a vacuum joint 5 made of stainless steel is seal-welded on the outer tube 2 for vacuuming operation. The left seal 3 is provided with a coaxially sleeved left inner sleeve 31 and a left outer sleeve 32 and a left inner support ring 33 seal-welded at the right ends of both, wherein the left end of the left inner sleeve 31 is seal-welded to the inner tube 1, and the left end of the left outer sleeve 32 is seal-welded to the outer tube 2 through a left outer support ring 34. The right sealing member 4 is provided with a coaxially sleeved right inner sleeve 41 and a right outer sleeve 42 and a right inner support ring 43 seal-welded to the left ends of both, wherein the right end of the right inner sleeve 41 is seal-welded to the inner tube 1, and the right end of the right outer sleeve 42 is seal-welded to the outer tube 2 via a right outer support ring 44.

[0028] Through the above arrangement, a cryogenic vacuum straight pipe with adaptive fluid pressure is formed. Compared with the existing cryogenic vacuum pipe with bellows compensator, the present invention makes the inner pipe 1 made of low expansion alloy steel 4J36, and utilizes its low expansion coefficient characteristics, so that it can adapt to the thermal expansion and contraction caused by temperature difference without setting a bellows compensator, which not only simplifies the structure, reduces the manufacturing difficulty and cost, but also does not generate a large load on the pipelines at both ends, and does not need to set an additional support structure. At the same time, the present invention improves the deformation ability of the left seal 3 and the right seal 4 by setting the left seal 3 and the right seal 4, and makes the left seal 3 and the right seal 4 adopt a circuitous structure, which can adapt to the impact of the fluid pressure on the inner pipe, and the left outer support ring 34 of the left seal 3 and the right outer support ring 44 of the right seal 4 can be used as a connecting seat for extending the cryogenic vacuum straight pipe. It only needs to be sealed and welded with the left outer support ring 34 and the right outer support ring 44 of the adjacent cryogenic vacuum straight pipe through the connecting pipe, so that multiple cryogenic vacuum straight pipes can be sequentially combined into a long-distance cryogenic vacuum pipeline, which improves the convenience of connection operation. In addition, the present invention improves corrosion resistance and prolongs service life by making the outer tube 2, the left seal 3, the right seal 4 and the vacuum joint 5 made of stainless steel. It should be noted that the vacuum joint is an existing component in the art, and its structure is well known to technicians.

[0029] As an optimization solution, the present specific implementation has a vacuum adsorption box 11 welded on the inner tube 1, and an adsorbent is provided in the vacuum adsorption box 11. This structure can maintain a reliable high vacuum degree in the vacuum chamber for a long time by providing the vacuum adsorption box 11 and the adsorbent, and using the adsorbent to adsorb the gas leaked in the vacuum chamber, thereby improving the maintenance convenience of the vacuum straight tube. In practical applications, the present invention generally uses 5A molecular sieve as an adsorbent, but is not limited to 5A molecular sieve, and other substances with equivalent functions can also be used as adsorbents, which can also achieve the technical purpose of the present invention. At the same time, in order to ensure the effectiveness and reliability of the adsorbent, an adsorbent filling port and a matching plug 12 are provided on the vacuum adsorption box 11 in this specific embodiment, and a filling operation hole corresponding to the adsorbent filling port and a matching cover 6 are provided on the outer tube 2, so that the adsorbent can be filled into the vacuum adsorption box 11 when the vacuum straight tube is assembled. Specifically, the vacuum adsorption box 11, the left seal 3 and the right seal 4 are first welded to the inner tube 1, and the left and right ends of the outer tube 2 are correspondingly welded to the left outer support ring 34 and the right outer support ring 44, and the vacuum joint 5 is welded to the outer tube 2; then, the adsorbent is filled into the vacuum adsorption box 11 through the filling operation hole and the adsorbent filling port, and after the filling is completed, the adsorbent filling port is sealed by the plug 12, and the cover 6 is sealed and welded at the filling operation hole; then, the vacuum operation is performed through the vacuum joint 5, and the vacuum joint 5 is closed after the vacuum is completed. As a specific structure, the present invention provides the vacuum adsorption box 11 with two annular side plates welded on the inner tube 1 and a cylindrical arc plate welded on the two annular side plates, wherein the cylindrical arc plate is provided with dispersed adsorption holes.

[0030] As an optimization scheme, in order to reduce the heat exchange between the inner tube 1 and the outer tube 2 and avoid deformation of the outer tube 2 due to low temperature, the present embodiment covers the inner tube 1, the left outer tube 32 and the right outer tube 42 with an insulation layer 7 made of insulation material to achieve the purpose of low heat leakage. Similarly, the present embodiment also covers the vacuum adsorption box 11 with an insulation layer 13 made of insulation material. In practical applications, the present invention generally uses a composite material composed of alkali-free glass fiber cloth, alkali-free glass fiber tape and aluminum foil as an insulation material to ensure the insulation effect, but is not limited to the above-listed forms, and other forms of insulation materials can also be used. In order to improve the structural stability, the present embodiment also fixes a support member 8 made of low heat leakage material on the outer wall of the inner tube 1. As a specific way of fixing, the present invention makes the support member 8 sleeved on the inner tube 1, and sets a retaining ring welded on the inner tube 1 and made of stainless steel on both sides of the support member 8, so that the support member 8 can be clamped and fixed by two retaining rings. In practical applications, the present invention generally uses polytetrafluoroethylene or epoxy fiberglass as low heat leakage materials, but is not limited to polytetrafluoroethylene and epoxy fiberglass. Other forms of low heat leakage materials can also be used to achieve the technical purpose of the present invention.

[0031] Based on the same concept, the present invention also provides a method for preparing the above-mentioned low-temperature vacuum straight tube, comprising the following steps:

[0032] S1. Weld the vacuum adsorption box 11, the left sealing member 3 and the right sealing member 4 to the inner tube 1 respectively, wherein the vacuum adsorption box 11 is provided with an adsorbent filling port.

[0033] S2. After the inner tube 1, the left outer tube 32 and the right outer tube 42 are covered with the insulation layer 7 by the insulation material, the left and right ends of the outer tube 2 are welded to the left outer support ring 34 and the right outer support ring 44 respectively, wherein the outer tube 2 is provided with a vacuum joint 5 and a filling operation hole.

[0034] S3, filling the vacuum adsorption box 11 with adsorbent through the filling operation hole and the adsorbent filling port, sealing the adsorbent filling port with the plug 12 after the filling is completed, and sealing the cover 6 at the filling operation hole.

[0035] S4, performing a vacuuming operation through the vacuuming joint 5, and closing the vacuuming joint 5 after the vacuuming is completed.

[0036] In order to improve the structural stability, in step S1, before welding the left sealing member 3 and the right sealing member 4, an operation of installing the support member 8 on the inner tube 1 is performed, which specifically includes the following steps:

[0037] S1-1, a support member 8 and two retaining rings correspondingly located on both sides of the support member 8 are sleeved on the inner tube 1.

[0038] S1-2, make two retaining rings clamp the support member 8 and weld them to the inner tube 1 respectively.

[0039] The preparation method of the low-temperature vacuum straight tube provided by the present invention has the advantages of simple process, convenient operation and high production efficiency.

[0040] Practical application shows that the low-temperature vacuum straight tube with adaptive fluid pressure and the preparation method thereof provided by the present invention can produce the following beneficial effects: 1. The present invention makes the inner tube made of low-expansion alloy steel 4J36 (i.e., Invar steel), and there is no need to use a bellows compensator, which greatly simplifies the low-temperature vacuum pipeline structure; 2. The present invention reduces heat leakage and ensures high vacuum life through the vacuum adsorption box and adsorbent through the vacuum interlayer design of corresponding welding of left and right seals at both ends of the inner and outer tubes, thereby improving the convenience of vacuum maintenance; 3. In the present invention, since the expansion coefficient of the inner tube is relatively low, the load on the support ring can be effectively reduced in practical applications, the influence of low-temperature stress is reduced, and the reliability under low-temperature conditions is improved; 4. The present invention can adapt to the impact of the fluid pressure on the inner tube by allowing the left seal and the right seal to adopt a circuitous structure, thereby improving safety and reliability.

[0041] The above embodiments are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the protection scope of the present invention. Without departing from the design concept of the present invention, various modifications made by those skilled in the art based on the technical solution of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A cryogenic vacuum straight tube with adaptive fluid pressure, characterized in that: The invention comprises an inner tube (1) and an outer tube (2) which are coaxially sleeved, wherein the inner tube (1) is made of low expansion alloy steel 4J36, and the outer tube (2) is made of stainless steel. A left sealing member (3) and a right sealing member (4) which are made of stainless steel are welded between the left and right ends of the outer tube (2) and the inner tube (1) respectively, and a vacuum joint (5) which is made of stainless steel is seal-welded on the outer tube (2). The left sealing member (3) comprises a left inner sleeve (31) and a left outer sleeve (32) which are coaxially sleeved, and a left inner sleeve (31) seal-welded on the right ends of the two. The left end of the left inner sleeve (31) is sealed and welded to the inner tube (1), and the left end of the left outer sleeve (32) is sealed and welded to the outer tube (2) via a left outer support ring (34). The right sealing member (4) comprises a right inner sleeve (41) and a right outer sleeve (42) which are coaxially sleeved, and a right inner support ring (43) which is sealed and welded to the left ends of both. The right end of the right inner sleeve (41) is sealed and welded to the inner tube (1), and the right end of the right outer sleeve (42) is sealed and welded to the outer tube (2) via a right outer support ring (44).

2. The cryogenic vacuum straight tube with adaptive fluid pressure according to claim 1, characterized in that: A vacuum adsorption box (11) is welded on the inner tube (1), and an adsorbent is arranged in the vacuum adsorption box (11).

3. The cryogenic vacuum straight tube with adaptive fluid pressure according to claim 2, characterized in that: The vacuum adsorption box (11) is provided with an adsorbent filling port and a matching plug (12), and the outer tube (2) is provided with a filling operation hole corresponding to the adsorbent filling port and a matching sealing cover (6).

4. The cryogenic vacuum straight tube with adaptive fluid pressure according to claim 3, characterized in that: The vacuum adsorption box (11) comprises two annular side plates welded to the inner tube (1) and a cylindrical arc plate welded to the two annular side plates, wherein the cylindrical arc plate is provided with adsorption holes arranged in a dispersed manner.

5. The cryogenic vacuum straight tube with adaptive fluid pressure according to claim 4, characterized in that: The inner tube (1), the left outer tube (32) and the right outer tube (42) are respectively covered with a heat insulation layer (7) made of a heat insulating material.

6. The cryogenic vacuum straight tube with adaptive fluid pressure according to claim 5, characterized in that: The vacuum adsorption box (11) is coated with a heat insulating layer (13) made of heat insulating material.

7. The cryogenic vacuum straight tube with adaptive fluid pressure according to claim 6, characterized in that: A support member (8) made of a low heat leakage material is fixed on the inner tube (1).

8. The cryogenic vacuum straight tube with adaptive fluid pressure according to claim 7, characterized in that: The support member (8) is sleeved on the inner tube (1), and retaining rings welded to the inner tube (1) are provided on both sides of the support member (8).

9. A method for preparing the low-temperature vacuum straight tube according to claim 7, characterized in that: The following steps are involved: S1. Welding the vacuum adsorption box (11), the left sealing member (3) and the right sealing member (4) to the inner tube (1) respectively, wherein the vacuum adsorption box (11) is provided with an adsorbent filling port; S2. After the inner tube (1), the left outer tube (32) and the right outer tube (42) are coated with a heat insulating layer (7) using a heat insulating material, the left and right ends of the outer tube (2) are welded to the left outer support ring (34) and the right outer support ring (44) respectively, wherein the outer tube (2) is provided with a vacuum joint (5) and a filling operation hole; S3, filling the adsorbent into the vacuum adsorption box (11) through the filling operation hole and the adsorbent filling port, sealing the adsorbent filling port through the plug (12) after the filling is completed, and sealing the cover (6) at the filling operation hole by welding; S4, performing a vacuuming operation through the vacuuming joint (5), and closing the vacuuming joint (5) after the vacuuming is completed.

10. The method for preparing a low-temperature vacuum straight tube according to claim 9, characterized in that: In step S1, before welding the left sealing member (3) and the right sealing member (4), an operation of installing a support member (8) on the inner tube (1) is performed, which includes the following steps: S1-1, sleeve a support member (8) and two retaining rings located on both sides of the support member (8) on the inner tube (1); S1-2, using two retaining rings to clamp the support member (8) and weld them to the inner tube (1) respectively.

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