Sealing structure for flange type low-pressure static strength assessment

Abstract

The invention discloses a sealing structure for flange type low-pressure static strength assessment. The sealing structure comprises a U-shaped fixing hoop, an O-shaped sealing ring and a thread standby fastening mouthpiece, the thread tightening mouthpiece is cylindrical, one end of the thread tightening mouthpiece is hexagonal, the end face of the other end of the thread tightening mouthpiece is provided with a sealing groove for accommodating the O-shaped sealing ring, and the outer surface of the thread tightening mouthpiece is provided with threads; the envelope of the U-shaped fixing hoop is cylindrical, a through hole is formed in the central axis, and a thread is arranged in the through hole and is in thread fit with the outer surface of the thread standby fastening mouthpiece; a cavity is formed in the U-shaped fixing hoop, a notch communicated with the cavity is formed in the side face of the U-shaped fixing hoop, a U-shaped hole is formed, a flange of a tested product can enter the cavity through the notch, and after the thread standby fastening mouthpiece is screwed into the through hole of the U-shaped fixing hoop through threads on the outer surface, the flange of the tested product can be tightly pressed in a sealed mode.

Description

Technical Field

[0001] The present invention relates to a sealing structure for flange-type low-pressure static strength assessment, which is used for assessing aerospace products such as electromagnetic valve frames and shells that have flange structures. Background Art

[0002] To ensure high performance and safe and reliable operation of rocket engines, flanged solenoid valve assemblies in aerospace products are critical components and welded parts. After manufacturing, they require low-pressure static strength testing to verify the structural static strength and weld quality. Using traditional jigs for testing has the following drawbacks: First, before installation, the traditional jig requires installing an F4 gasket into the annular groove of the jig flange. The jig flange is then aligned with the solenoid valve assembly flange, and several bolts are used to secure them diagonally. When tightening the screws, care must be taken to ensure uniform clearance around the two flanges to ensure a good seal during the test. Second, after testing, the traditional jig requires removing several bolts diagonally to separate the jig and product flanges. Third, when installing the two flanges, the clearances must be consistent. Failure to do so can cause damage to both the product and jig flanges, potentially leading to leakage of the test fluid. Fourth, if the product flange structure is irregular, the jig screws must be aligned with the product flange holes before installation. The traditional operation method is time-consuming, labor-intensive and can no longer meet the needs of fast-paced, large-scale production models. Therefore, it is urgent to invent new tooling to solve this problem, which is a technical problem that needs to be solved urgently by technicians in this field. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: to overcome the shortcomings of the existing technology and provide a sealing structure for flange-type low-pressure static strength assessment, which adopts end-face sealing O-ring and threaded connection structure, can be self-aligned, will not damage the flange of the solenoid valve assembly product, and has high static strength assessment test efficiency, easy disassembly and assembly, and small size, light weight, and simple structure.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A sealing structure for flange-type low-pressure static strength testing comprises a U-shaped fixing clamp, a threaded adapter, and an O-ring. The end face of the threaded adapter is provided with a sealing groove, within which the O-ring resides. Before testing, the flange end of the product under test (e.g., a flanged solenoid valve assembly) is placed into the U-shaped hole of the U-shaped fixing clamp. The O-ring is then inserted into the sealing groove of the threaded adapter. The external threads of the threaded adapter are then mated with the internal threads of the U-shaped fixing clamp, resulting in approximately 25% pre-compression of the O-ring on the threaded adapter against the product flange. During the test, the fluid test medium acts on the product flange, the O-ring, and the threaded adapter, generating a sealing pressure on the O-ring surface, achieving a seal. After the test, the hexagonal screw on the threaded adapter is turned counterclockwise to create relative displacement between it and the internal threads of the U-shaped fixing clamp, separating the O-ring from the product flange and allowing the product to be removed.

[0006] The U-shaped hole of the U-shaped fixing clamp serves to limit and secure the product during installation. This sealing structure allows the product flange to self-align. This sealing structure, when used in conjunction with the connecting flange feature, allows for both hydraulic and air tightness testing.

[0007] When the product under test (i.e., the solenoid valve product) is undergoing a static strength assessment test, the sealing structure uses an end face seal. The metal surface of the solenoid valve product's flange has no contact with the metal of the threaded connection nozzle. The metal surface of the solenoid valve product's flange will not be subjected to excessive assembly stress, effectively eliminating the risk of the solenoid valve product's flange metal surface being crushed.

[0008] When testing flange-type aerospace products, O-ring end face sealing is used. By tightening the U-shaped hole of the U-shaped fixing clamp and the matching thread of the spare tightening nozzle, quick assembly is achieved, avoiding the use of fasteners such as bolts and nuts, with short installation time, high efficiency and easy disassembly and assembly.

[0009] During use, it is necessary to ensure that the matching threads of the threaded connection nozzle and the U-shaped fixing clamp meet the accuracy requirements and the central axes of the two coincide with each other.

[0010] During use, it is necessary to ensure that the inner diameter of the O-ring on the end face of the threaded joint is 2mm-3mm larger than the inner hole size of the product flange center.

[0011] During use, it is necessary to ensure that the diameter of the O-ring is 0.2mm-0.3mm higher than the depth of the sealing groove on the upper end face of the threaded connection nozzle.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] (1) The sealing structure of the present invention greatly improves the test efficiency when conducting static strength assessment tests on flange-type aerospace products. When installing the product for testing, it is only necessary to install the product flange end in the U-shaped fixing clamp, then tighten the threaded joint clockwise. The threaded guide movement squeezes the O-ring to achieve a reliable seal. This has been applied in a number of solenoid valve assembly products, with high test efficiency and good results.

[0014] (2) Based on the sealing structure of the present invention, when the solenoid valve assembly product is subjected to a static strength assessment test, one end of the flange of the solenoid valve assembly product contacts the tooling O-ring, and the threaded transmission motion guide is convenient for disassembly.

[0015] (3) Based on the sealing structure of the present invention, when the solenoid valve assembly product is subjected to a static strength assessment test, the flange and tooling of the solenoid valve assembly product adopt an end face sealing structure, which does not damage the product.

[0016] (4) The tooling produced by the present invention has the advantages of small size, light weight, low production cost, simple structure, high test efficiency, easy carrying and easy assembly and disassembly.

[0017] (5) Based on the sealing structure of the present invention, it can also be applied to product testing with circular or irregular flanges. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is an exploded view of the sealing structure of the present invention;

[0019] Figure 2 This is the overall assembly diagram of the sealing structure of the present invention;

[0020] Figure 3 This is a cross-sectional view of the sealing structure of the present invention.

[0021] Reference numerals: 1-threaded fastening nozzle, 2-O-ring, 3-U-shaped fixing clamp, 4-tested product. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0023] A sealing structure for flange-type low-pressure static strength assessment realizes movement and guidance through the mating threads of the threaded fastening nozzle 1 and the U-shaped fixed clamp 3, and deforms to form an annular sealing pressure ratio by squeezing the O-ring 3 on the end face of the threaded fastening nozzle 1 into contact with the flange of the product to be tested 4, thereby realizing low-pressure static strength sealing. The sealing structure of the present invention has high reliability, reasonable design and good sealing performance. After the test, there are no defects such as pressure damage to the flange of the product to be tested 4. The operation is simple and the skill level required is low. It avoids the defects of the traditional test tooling such as the flange tooling docking the product flange and bolt tightening, reduces labor, reduces personnel costs, and can adapt to the rapid testing of aerospace products. The sealing structure of the present invention has good performance and long service life. A set of tooling can be used for mass production and has a wide range of promotion. It can be applied to the testing of various aerospace products with flange structures by changing the size, and has high economic value.

[0024] Specifically, a sealing structure for flange low-pressure static strength assessment includes a U-shaped fixing clamp 3, an O-shaped sealing ring 2, a threaded fastening nozzle 1 (such as Figure 1 shown).

[0025] The threaded fastening nozzle 1 is cylindrical, with a hexagonal shape at one end and a sealing groove for accommodating an O-ring 2 on the end face of the other end. The outer surface of the threaded fastening nozzle 1 is provided with threads; the envelope of the U-shaped fixing clamp 3 is cylindrical, with a through hole provided at the central axis, and a thread provided in the through hole, which cooperates with the outer surface thread of the threaded fastening nozzle 1; a cavity is provided inside the U-shaped fixing clamp 3, and a notch is provided on the side of the U-shaped fixing clamp 3 that communicates with the cavity, forming a U-shaped hole. The flange of the product under test 4 can enter the cavity through the notch. When the threaded fastening nozzle 1 is screwed into the through hole of the U-shaped fixing clamp 3 through the outer surface thread, the flange of the product under test 4 can be sealed and compressed.

[0026] Before conducting the static strength test, first check whether the O-ring 2 has cracks, end surface scratches, deterioration, etc. If so, it must be replaced or repaired. The thread guide movement of the U-shaped fixing clamp 3 and the threaded joint 1 is qualified. If not, replace it.

[0027] Apply grease to all threads and O-rings 2, install the O-ring 2 in the groove on the end face of the threaded joint 1, and finally apply grease to one end of the flange of the product to be tested 4 and install it into the U-shaped hole of the fixing clamp 3. By tightening the threaded joint 1, the matching threads of the threaded joint 1 and the U-shaped fixing clamp 3 are moved and guided. By squeezing the O-ring 2 on the end face of the threaded joint 1 and contacting with the flange of the product to be tested 4, an annular sealing pressure ratio is formed (such as Figure 2As shown in the figure, the external thread of the product under test 4 is blocked with a tool plug. At this time, the product under test 4 and the sealing structure form a closed cavity. Then, the external threaded nozzle of the threaded fastening nozzle 3 is connected and tightened with the pipe nozzle on the test bench. Before the test, the armored chamber door is closed. When the product under test 4 is subjected to the hydraulic test, the fluid medium water acts on the inner cavity of the threaded fastening nozzle 1, the inner cavity of the product under test 4, and the O-ring 2. At this time, the O-ring generates a specific pressure to achieve a seal. Then, the surface of the product under test 4 can be observed through the glass door of the armored chamber to see whether there are defects such as sweating and small water droplets.

[0028] Before conducting an airtightness test on a solenoid valve assembly, first loosen the threaded joint 1 counterclockwise. This will allow the O-ring 2 to separate from the flange end of the product under test 4 through threaded motion. Remove the product under test 4 and blow out any moisture from its interior. Install the product under test 4 in the U-shaped fixing clamp 3, and finally tighten the threaded joint 1 clockwise. Then, align and tighten the threaded joint 1 with the pipe joint on the test bench, then place it in an alcohol tank. Close the armored chamber door, start the equipment, and maintain pressure as per regulations. Observe the weld surface of the product under test 4 (e.g., a solenoid valve assembly) for bubbles. Upon completion of the test, remove the sealing structure and the product under test 4. Figure 3 It is a cross-sectional view of the sealing structure and the tested product 4 after installation.

[0029] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

[0030] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solutions of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A sealing structure for flange low-pressure static strength assessment, characterized by: It includes a U-shaped fixing clamp (3), an O-shaped sealing ring (2), and a threaded fastening nozzle (1); The threaded fastening nozzle (1) is cylindrical, with a hexagonal shape at one end and a sealing groove for accommodating an O-ring (2) at the end face of the other end. The outer surface of the threaded fastening nozzle (1) is provided with a thread. The envelope of the U-shaped fixing clamp (3) is cylindrical, with a through hole at the central axis. The through hole is provided with a thread and matches the outer surface thread of the threaded fastening nozzle (1). The interior of the U-shaped fixing clamp (3) is provided with a cavity, and the side of the U-shaped fixing clamp (3) is provided with a notch connected to the cavity to form a U-shaped hole. The flange of the product to be tested (4) can enter the cavity through the notch. When the threaded fastening nozzle (1) is screwed into the through hole of the U-shaped fixing clamp (3) through the outer surface thread, the flange of the product to be tested (4) can be sealed and pressed.

2. The sealing structure according to claim 1, wherein: Before the static strength test, check whether the O-ring (2) has cracks, end surface scratches, or deterioration. If so, it must be replaced or repaired.

3. The sealing structure according to claim 1, wherein: Before the static strength test is carried out, the thread guide movement of the U-shaped fixing clamp (3) and the threaded fastening nozzle (1) is checked to see if it is qualified. If it is unqualified, it is replaced.

4. The sealing structure according to claim 1, wherein: When the sealing structure is used, grease is applied to all threads and O-rings (2), and the O-rings (2) are installed in the end face groove of the threaded fastening nozzle (1). Finally, grease is applied to one end of the flange of the product to be tested (4) and the flange is installed in the U-shaped hole of the fixing clamp (3). By tightening the threaded fastening nozzle (1), the matching threads of the threaded fastening nozzle (1) and the U-shaped fixing clamp (3) are moved and guided. By squeezing the O-rings (2) on the end face of the threaded fastening nozzle (1) and contacting with the flange of the product to be tested (4), the O-rings (2) are deformed to form an annular sealing pressure ratio. The external threads of the product to be tested (4) are blocked with a tool plug. At this time, the product to be tested (4) and the sealing structure form a closed cavity. Then, the external threaded nozzle of the threaded fastening nozzle (3) is connected to the pipe nozzle on the test bench and tightened.

5. The sealing structure according to claim 4, characterized in that: Before the test, the armor chamber door is closed. When the product under test (4) is subjected to a hydraulic test, the fluid medium water acts on the inner cavity of the threaded joint (1), the inner cavity of the product under test (4), and the O-ring (2). At this time, the O-ring generates a specific pressure to achieve sealing, thereby observing whether there is sweat or small water droplets on the surface of the product under test (4) through the armor chamber glass door.

6. The sealing structure according to claim 5, characterized in that: Before the solenoid valve assembly product is subjected to an airtightness test, the threaded joint (1) should be loosened counterclockwise. At this time, the O-ring (2) is separated from the flange end of the product under test (4) through the threaded movement. The product under test (4) is taken out and the water vapor in its cavity is blown out. The product under test (4) is then installed in the U-shaped fixing clamp (3). Finally, the threaded joint (1) is tightened clockwise. The threaded joint (1) is then connected to the pipe joint on the test bench and tightened. The joint is then placed in the alcohol tank. The armored room door is closed and the equipment is started to maintain pressure according to the regulations. Observe whether there are bubbles on the surface of the weld of the product under test (4). After the test is completed, the sealing structure and the product under test (4) are removed.

7. The sealing structure according to claim 1, wherein: The O-ring (2) on the threaded fastening nozzle (1) contacts the flange of the product to be tested (4) to generate pre-compression.

8. The sealing structure according to claim 1, wherein: The U-shaped hole of the U-shaped fixing clamp (3) plays a role in limiting and fixing the product to be tested (4) during the product installation process. The use of this sealing structure can achieve self-alignment of the flange of the product to be tested (4).

9. The sealing structure according to claim 1, wherein: When the product under test (4) is undergoing a static strength assessment test, the sealing structure adopts an end face seal, and the metal surface of the flange of the product under test (4) has no contact with the metal of the threaded connection nozzle (1). The metal surface of the flange of the product under test (4) will not be subjected to excessive assembly stress, effectively eliminating the risk of the metal surface of the flange of the solenoid valve product being crushed.

10. The sealing structure according to claim 1, wherein: The matching threads of the threaded fastening nozzle (1) and the U-shaped fixing clamp (3) meet the precision requirements so that the central axes of the two coincide with each other.

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