Low temperature seal test fixture

Abstract

The application relates to a low-temperature sealing test jig and belongs to the technical field of test jigs. The application solves the problems that the existing test jigs are difficult to connect test pipelines under low-temperature working conditions and are difficult to ensure the sealing performance during the test process. A to-be-tested valve body is fixed between the blind plate and the flange ring, a pressing seat is arranged between the to-be-tested valve body and the blind plate, the pressing seat is in abutment with the opening end of the to-be-tested valve body, a sealing ring group is arranged between the pressing seat and the to-be-tested valve body, the butt-welding end of the to-be-tested valve body is inserted into the flange ring, a ring groove is formed in the flange ring, a split ring is arranged in the ring groove, and the inner wall of the split ring is in press-fitting positioning with the outer wall of the butt-welding end of the to-be-tested valve body. The to-be-tested valve body is quickly and stably clamped by bolt connection of the blind plate and the flange ring, the connection process of the test pipeline under the extreme low-temperature environment is obviously simplified, and the sealing reliability of the test jig under the low-temperature working condition is ensured by arranging the sealing ring group.

Description

Technical Field

[0001] This invention relates to the field of test fixture technology, and more particularly to a low-temperature sealing test fixture. Background Technology

[0002] Cryogenic valves, including ball valves, butterfly valves, gate valves, and check valves, play crucial roles in equipment for shut-off, check valves, and regulation. They are suitable for media such as ethylene, liquid oxygen, liquid hydrogen, liquefied natural gas, and liquefied petroleum products, and are mostly used in cryogenic environments down to -163°C. Given these extreme cryogenic conditions, the design of cryogenic valves, in addition to adhering to general valve design principles, must ensure safe and reliable operation under such harsh conditions, achieve tight sealing performance, and maintain flexible and smooth opening and closing functions.

[0003] Cryogenic valves undergo performance testing at room temperature according to general valve standards. After passing the test, they should also be subjected to performance testing at low temperatures. Generally, performance testing of cryogenic valves needs to be carried out at -196℃. Since the test connection method is mostly butt welding, it is difficult to connect the test pipeline under low temperature conditions using traditional test fixtures, and it is also difficult to ensure the stability and sealing of the test process. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned problems and provides a low-temperature sealing test fixture.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a low-temperature sealing test fixture, including a blind plate, a flange ring, a clamping seat, and a split ring. The blind plate has a plurality of first connecting holes arranged circumferentially. The flange ring has a plurality of second connecting holes that are vertically opposite to the first connecting holes. Each set of first connecting holes and second connecting holes is connected by bolts. A valve body to be tested is fixed between the blind plate and the flange ring. A clamping seat is provided between the valve body to be tested and the blind plate. The clamping seat abuts against the open end of the valve body to be tested, and a sealing ring group is provided between the two. The butt weld end of the valve body to be tested is inserted into the flange ring. An annular groove is provided on the flange ring. A split ring is provided in the annular groove. The inner wall of the split ring is press-fitted and positioned against the outer wall of the butt weld end of the valve body to be tested.

[0006] Furthermore, the butt weld end of the valve body under test is connected to a transition joint, and the other end of the transition joint is connected to a helium gas pipeline.

[0007] Furthermore, the sealing ring assembly includes a first sealing ring and a second sealing ring, and the clamping seat has a first annular groove and a second annular groove. The first sealing ring is disposed in the first annular groove, and the second sealing ring is disposed in the second annular groove.

[0008] Furthermore, the shape of the clamping seat corresponds to the shape of the open end of the valve body under test.

[0009] Furthermore, the inner diameter of the open ring is smaller than the maximum outer diameter of the butt weld end of the valve body under test.

[0010] Furthermore, the blind flange, clamping seat, split ring, and flange ring are all made of 304 stainless steel.

[0011] Furthermore, the first and second sealing rings are made of polytetrafluoroethylene.

[0012] Compared with the prior art, the present invention has the following advantages: This invention ensures the sealing reliability of the test fixture under low-temperature conditions by setting a clamping seat that abuts against the open end of the valve body under test and a sealing ring assembly between the two, and working in conjunction with the positioning structure formed by the flange ring and the split ring. This effectively resists leakage paths that may be caused by material shrinkage at low temperatures and ensures the stability of the test medium pressure.

[0013] This invention achieves rapid and stable clamping and alignment of valve bodies of different specifications and types by bolting a blind plate to a flange ring and utilizing the clamping action of the split ring. This design significantly simplifies the connection process of test pipelines in extreme low-temperature environments, improves clamping efficiency and the convenience of repeated operations, and greatly enhances connection stability at low temperatures. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a cross-sectional view of the low-temperature sealing test fixture in this invention; Figure 2 This is a schematic diagram showing the positional relationship between the clamping seat and the sealing ring assembly in this invention; In the figure: 1. Blind flange; 2. Compression seat; 3. First sealing ring; 4. Flange ring; 5. Split ring; 6. Valve body to be tested; 7. Transition joint; 8. Second sealing ring; 9. First annular groove; 10. Second annular groove; 11. First connecting hole; 12. Second connecting hole. Detailed Implementation

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0020] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0021] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0022] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0023] See appendix Figure 1-2 This embodiment describes a low-temperature sealing test fixture, comprising a blind plate 1, a flange ring 4, a clamping seat 2, and a split ring 5. The blind plate 1 has multiple first connecting holes 11 circumferentially arranged on it. The flange ring 4 has multiple second connecting holes 12 vertically opposite to the first connecting holes 11. Each set of first connecting holes 11 and second connecting holes 12 is connected by bolts. A valve body 6 to be tested is fixed between the blind plate 1 and the flange ring 4. A clamping seat 2 is provided between the valve body 6 and the blind plate 1. The clamping seat 2 abuts against the open end of the valve body 6, and a sealing ring assembly is provided between them. The butt-welded end of the valve body 6 is inserted into the flange ring 4. An annular groove is formed on the flange ring 4, and a split ring 5 is provided within the annular groove. The inner wall of the split ring 5 is press-fitted and positioned against the outer wall of the butt-welded end of the valve body 6.

[0024] This invention, through the setting of a clamping seat 2 that abuts against the open end of the valve body 6 under test and a sealing ring assembly between them, and in conjunction with the positioning structure formed by the flange ring 4 and the split ring 5, ensures the sealing reliability of the test fixture under cryogenic conditions, effectively resisting leakage paths that may be caused by material shrinkage at low temperatures, and ensuring the stability of the test medium pressure. This invention achieves rapid and stable clamping and alignment of valve bodies of different specifications and types by bolting the blind plate 1 to the flange ring 4 and utilizing the clamping action of the split ring 5. This design significantly simplifies the connection process of test pipelines in extreme low-temperature environments, improves clamping efficiency and the convenience of repeated operations, and overcomes the problem of poor connection stability caused by inconvenient operation at low temperatures.

[0025] The butt-welded end of the valve body 6 under test is connected to a transition joint 7, and the other end of the transition joint 7 is connected to a helium gas pipeline. By setting the transition joint 7, a reliable connection between the valve body 6 under test and the helium gas pipeline is achieved, thereby enabling efficient and accurate sealing tests.

[0026] The sealing ring assembly includes a first sealing ring 3 and a second sealing ring 8. The clamping seat 2 has a first annular groove 9 and a second annular groove 10. The first sealing ring 3 is disposed in the first annular groove 9, and the second sealing ring 8 is disposed in the second annular groove 10. Specifically, the first sealing ring 3 is located between the bottom surface of the clamping seat 2 and the top surface of the valve body 6 under test, and the second sealing ring 8 is located between the inner wall of the clamping seat 2 and the outer wall of the valve body 6 under test. The first sealing ring 3 and the second sealing ring 8 form a double-layer seal between the open end of the valve body 6 under test and the clamping seat 2, effectively preventing leakage paths that may occur due to material shrinkage at low temperatures, and ensuring stable pressure of the test medium.

[0027] The shape of the clamping seat 2 corresponds to the shape of the open end of the valve body 6 under test. Specifically, the valve body 6 under test includes ball valves, butterfly valves, gate valves, check valves, etc., and the open ends of each type of valve body 6 are different. Therefore, the clamping seat 2 has various specifications and shapes to adapt to the open ends of different valve bodies 6. This ensures that the clamping seat 2 and the open end of the valve body 6 under test are tightly fitted, ensuring uniform pressure transmission and reliable sealing. It can effectively adapt to the end structures of different valve bodies, thereby achieving stable and leak-free test conditions at extreme low temperatures.

[0028] The inner diameter of the split ring 5 is smaller than the maximum outer diameter of the butt weld end of the valve body 6 under test. Specifically, the split ring 5 and the butt weld end of the valve body 6 under test form an interference fit, generating a radial clamping force during assembly, thereby achieving reliable sealing and fastening, effectively preventing leakage and loosening of the connection that may be caused by material shrinkage at low temperatures, and ensuring the stability of the connection.

[0029] The blind flange 1, clamping seat 2, split ring 5, and flange ring 4 are all made of 304 stainless steel. The use of 304 stainless steel ensures that each component possesses excellent low-temperature toughness and dimensional stability in extreme low-temperature environments of -196℃ and below, effectively preventing cracking or deformation caused by cold brittleness, thereby guaranteeing the overall structural integrity and sealing reliability of the fixture.

[0030] The first sealing ring 3 and the second sealing ring 8 are made of polytetrafluoroethylene (PTFE). The use of PTFE ensures that it maintains excellent flexibility, dimensional stability, and chemical inertness even at extreme low temperatures of -196°C, guaranteeing that the sealing rings do not harden, crack, or permanently deform under cryogenic conditions and repeated thermal cycling, thus providing a durable and reliable sealing effect.

[0031] The present invention discloses a low-temperature sealing test fixture, the specific working steps of which are described below: The valve body 6 to be tested is placed between the clamping seat 2 and the flange ring 4. The clamping seat 2 and the valve body 6 are fixed together by bolts between the blind plate 1 and the flange ring 4. Liquid nitrogen is injected into an insulated chamber to cool the valve body 6. The liquid nitrogen level submerges the valve body and the test fixture as a whole. An insulation cover is placed on the outside of the insulated chamber to ensure that the test is not affected by the evaporation of liquid nitrogen gas. A helium pipeline is connected to the transition joint 7 and a certain pressure is applied. Observe whether bubbles rise to the surface of the liquid nitrogen. This observation is used to determine whether the valve body 6 leaks. It is essential to ensure that only the workpiece itself may leak, and that the connection between the fixture and the workpiece is leak-free.

[0032] The valve body 6 under test is connected to the test pipeline through the experimental fixture of this invention. The valve body 6 under test, together with the fixture, needs to be immersed in liquid nitrogen. Both the valve body 6 under test and the fixture will be affected by the physical factors of thermal expansion and contraction under low temperature conditions. Therefore, during the test, the installation and use of the fixture should not affect the deformation of the valve body 6 under test or the valve's sealing test results.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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 low-temperature sealing test fixture, characterized in that: The device includes a blind plate (1), a flange ring (4), a clamping seat (2), and a split ring (5). The blind plate (1) has multiple first connecting holes (11) arranged circumferentially. The flange ring (4) has multiple second connecting holes (12) that are vertically opposite to the first connecting holes (11). Each set of first connecting holes (11) and second connecting holes (12) is connected by bolts. A valve body (6) to be tested is fixed between the blind plate (1) and the flange ring (4). A clamping seat (2) is provided between the valve body (6) to be tested and the blind plate (1). The clamping seat (2) abuts against the open end of the valve body (6) to be tested, and a sealing ring group is provided between the two. The butt weld end of the valve body (6) to be tested is inserted into the flange ring (4). An annular groove is provided on the flange ring (4). A split ring (5) is provided in the annular groove. The inner wall of the split ring (5) is press-fitted and positioned with the outer wall of the butt weld end of the valve body (6) to be tested.

2. The low-temperature sealing test fixture according to claim 1, characterized in that: The butt weld end of the valve body (6) to be tested is connected to the transition joint (7), and the other end of the transition joint (7) is connected to the helium pipeline.

3. The low-temperature sealing test fixture according to claim 1, characterized in that: The sealing ring assembly includes a first sealing ring (3) and a second sealing ring (8). The pressing seat (2) has a first annular groove (9) and a second annular groove (10). The first annular groove (9) contains the first sealing ring (3), and the second annular groove (10) contains the second sealing ring (8).

4. The low-temperature sealing test fixture according to claim 1, characterized in that: The shape of the clamping seat (2) corresponds to the shape of the open end of the valve body (6) to be tested.

5. The low-temperature sealing test fixture according to claim 1, characterized in that: The inner diameter of the split ring (5) is smaller than the maximum outer diameter of the butt weld end of the valve body (6) to be tested.

6. The low-temperature sealing test fixture according to claim 1, characterized in that: The blind flange (1), clamping seat (2), split ring (5) and flange ring (4) are all made of 304 stainless steel.

7. A low-temperature sealing test fixture according to claim 3, characterized in that: The first sealing ring (3) and the second sealing ring (8) are made of polytetrafluoroethylene.

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