A method of increasing the sealability of a safety valve

Abstract

The present application relates to a kind of method for increasing the sealing performance of safety valve.The present application includes the valve sleeve of safety valve, the inner cavity of valve sleeve includes with the cooperation installation of valve core, the inner cavity includes coaxially arranged first cavity, second cavity and third cavity, second cavity is equipped with the taper transition cavity between third cavity, the side wall of taper transition cavity and the side wall of third cavity form the contact portion contacted with the valve core of safety valve;Punch is coaxially arranged with the inner cavity, punch includes punch rod, the extension structure of gradually reducing diameter is extended to one end of punch rod and is connected with blade by extension structure, blade includes first blade section and second blade section, the taper of the junction section of first blade section and second blade section two sides changes from big to small from first blade section to second blade section direction, the junction section of first blade section and second blade section is contacted with contact portion;Plastic deformation occurs in the region of contact portion by exerting stamping force in the axial direction of punch.The sealing performance of safety valve is improved and the scrap rate is reduced.

Description

Technical Field

[0001] This invention relates to the field of safety valve processing technology, and in particular to a method for increasing the sealing performance of a safety valve. Background Technology

[0002] Currently, safety valves use a conical hard-contact seal between the valve core and valve sleeve. Due to external factors such as machining tools and materials, the contact profile between the valve sleeve and valve core may deviate to some extent, leading to unstable sealing of the assembly. For example... Figures 1 to 2 As shown, during operation, both the valve core 200 and the valve sleeve 100 of the safety valve bear very high pressure. After prolonged use, the mating surface 210 between the valve core 200 and the valve sleeve 100 experiences severe wear, increasing the stress area of ​​the valve core and thus exacerbating wear between the valve core 200 and the valve sleeve 100. Therefore, a method to improve the sealing performance of the safety valve is urgently needed, thereby increasing the sealing performance between the valve sleeve and the valve core. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for increasing the sealing performance of a safety valve, which can enhance the sealing performance between the valve sleeve and the valve core, thereby improving the manufacturing quality of the safety valve.

[0004] To solve the above-mentioned technical problems, the present invention provides a method for increasing the sealing performance of a safety valve, comprising the following steps:

[0005] A valve sleeve for processing a safety valve, the valve sleeve including an inner cavity that mates with a valve core, the inner cavity including a first cavity, a second cavity and a third cavity arranged coaxially, a tapered transition cavity being provided between the second cavity and the third cavity, and a contact portion being formed between the side wall of the tapered transition cavity and the side wall of the third cavity that contacts the valve core of the safety valve;

[0006] The punch is coaxially arranged with the inner cavity. The punch includes a punch rod. One end of the punch rod extends into an extension structure with a gradually decreasing diameter and is connected to a cutting edge through the extension structure. The cutting edge includes a first cutting segment and a second cutting segment connected to the first cutting segment. Both the first cutting segment and the second cutting segment are tapered. The tapering on both sides of the connection section between the first cutting segment and the second cutting segment decreases from large to small from the first cutting segment to the second cutting segment.

[0007] When a punching force is applied axially to the punch, the contact area of ​​the first cutting section and the second cutting section comes into contact with the contact part, causing plastic deformation in the contact area, with the amount of plastic deformation being 0.01-0.02 mm.

[0008] In one embodiment of the present invention, the impact force is in the range of 4-4.5kN, and the axial length of the connecting section is 0.3±0.1mm.

[0009] In one embodiment of the present invention, the punch rod includes a first rod body, and a second rod body extends coaxially from one end of the first rod body along the axial direction. The extension structure is located at the end of the second rod body away from the first rod body. The diameter of the second rod body is smaller than that of the first rod body, so that a step is formed between the first rod body and the second rod body. The second rod body extends into the second cavity and is clearance-fitted with the second cavity.

[0010] In one embodiment of the present invention, the cross-section of the extended structure is an isosceles trapezoid.

[0011] In one embodiment of the present invention, the angle between the two hypotenuses of the cross section of the isosceles trapezoid of the extended structure is 80±1°.

[0012] In one embodiment of the present invention, the cross-sections of the first cutting segment and the second cutting segment are both isosceles trapezoids, and the included angle between the two hypotenuses of the cross-section of the isosceles trapezoid of the first cutting segment is greater than the included angle between the two hypotenuses of the cross-section of the isosceles trapezoid of the second cutting segment.

[0013] In one embodiment of the present invention, the included angle between the two hypotenuses of the cross section of the first connecting segment isosceles trapezoid is 30.5 ± 0.25°.

[0014] In one embodiment of the present invention, the included angle between the two hypotenuses of the cross section of the second connecting segment isosceles trapezoid is 22.5 ± 0.25°.

[0015] In one embodiment of the present invention, the surface of the first rod is provided with a fixing groove.

[0016] In one embodiment of the present invention, the punch is integrally formed from eutectic graphite steel.

[0017] The technical solution of the present invention has the following advantages compared with the prior art:

[0018] This invention discloses a method for increasing the sealing performance of a safety valve. By setting a first cutting edge and a second cutting edge on the punch, the taper of the connecting section between the first and second cutting edges gradually decreases from the first cutting edge towards the second cutting edge. The connecting section is brought into contact with a contact portion, and pressure is applied to cause a plastic deformation of 0.01-0.02 mm in the contact portion. Verification showed that the contour of the valve sleeve sealing area (i.e., around the contact portion) can better fit with the valve core surface, thereby increasing the sealing performance. This invention improves the sealing performance of safety valves and reduces the scrap rate. Attached Figure Description

[0019] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] Figure 1 This is a schematic diagram of a safety valve structure.

[0021] Figure 2 yes Figure 1 A magnified view of a portion of the image.

[0022] Figure 3 This is a schematic diagram of the valve sleeve.

[0023] Figure 4 yes Figure 3 A cross-sectional view along aa.

[0024] Figure 5 This is a schematic diagram of the punch of the present invention.

[0025] Figure 6 yes Figure 1 A sectional view along AA.

[0026] Figure 7 yes Figure 2 A magnified view of a section at point C.

[0027] Figure 8 This is a schematic diagram of the fit between the punch and the valve sleeve of the present invention.

[0028] Explanation of reference numerals in the accompanying drawings: 100, valve sleeve; 110, first cavity; 120, second cavity; 130, third cavity; 140, conical transition cavity; 150, contact part; 200, valve core; 210, mating surface; 1, punch rod; 11, first rod body; 111, fixing groove; 12, second rod body; 2, extension structure; 3, cutting edge; 31, first cutting segment; 32, second cutting segment; 33, connecting segment. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0030] This invention defines certain directional terms. Unless otherwise stated, the directional terms used, such as "up," "down," "left," "right," "inner," and "outer," are used for ease of understanding and therefore do not constitute a limitation on the scope of protection of this invention.

[0031] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] Reference Figures 1 to 8 As shown, a method for increasing the sealing performance of a safety valve according to the present invention includes the following steps:

[0034] Step S1: Machining the valve sleeve 100 of the safety valve, the valve sleeve 100 includes an inner cavity that mates with the valve core, the inner cavity includes a first cavity 110, a second cavity 120 and a third cavity 130 arranged coaxially, a tapered transition cavity 140 is provided between the second cavity 120 and the third cavity 130, and a contact portion 150 (i.e., the mating surface 210 between the valve core 200 and the valve sleeve 100) is formed between the side wall of the tapered transition cavity 140 and the side wall of the third cavity 130, which contacts the valve core of the safety valve.

[0035] Step S2: The punch is coaxially arranged with the inner cavity. The punch includes a punch rod 1. One end of the punch rod 1 extends into an extension structure 2 with a gradually decreasing diameter, and a cutting edge 3 is connected to the extension structure 2. The cutting edge 3 includes a first cutting segment 31 and a second cutting segment 32 connected to the first cutting segment 31. Both the first cutting segment 31 and the second cutting segment 32 are tapered. The taper on both sides of the connection section 33 between the first cutting segment 31 and the second cutting segment 32 decreases from large to small in the direction from the first cutting segment 31 to the second cutting segment 32.

[0036] Step S3: Apply a punching force axially to the punch, so that when the connecting section 33 of the first cutting segment 31 and the second cutting segment 32 contacts the contact portion 150, the taper of the first cutting segment 31 suddenly increases, causing plastic deformation in the contact portion 150 area. The amount of plastic deformation is controlled within 0.01-0.02 mm. The punching force ranges from 4 to 4.5 kN, and the axial length of the connecting section 33 is 0.3 ± 0.1 mm. The valve sleeve 100 is made of 20CrMo material.

[0037] Specifically, the punch rod 1 includes a first rod body 11, and a second rod body 12 extends coaxially from one end along the axial direction of the first rod body 11. The extension structure 2 is located at the end of the second rod body 12 away from the first rod body 11. The diameter of the second rod body 12 is smaller than that of the first rod body 11, so that a step is formed between the first rod body 11 and the second rod body 12. The second rod body 12 extends into the second cavity 120 and is clearance-fitted with the second cavity 120.

[0038] Specifically, the cross-section of the extension structure 2 is an isosceles trapezoid.

[0039] Specifically, such as Figure 6 As shown at point a in the diagram, the angle between the two hypotenuses of the isosceles trapezoidal cross section of the extended structure 2 is 80±1°.

[0040] Specifically, the cross-sections of the first cutting segment 31 and the second cutting segment 32 are both isosceles trapezoids, and the angle between the two hypotenuses of the cross-section of the isosceles trapezoid of the first cutting segment 31 is greater than the angle between the two hypotenuses of the cross-section of the isosceles trapezoid of the second cutting segment 32.

[0041] Specifically, such as Figure 7 As shown at point b, the angle between the two hypotenuses of the cross section of the first connecting segment 33 (i.e., the taper of the first connecting segment 33) is 30.5 ± 0.25°.

[0042] Specifically, such as Figure 7 As shown at point c, the angle between the two hypotenuses of the cross section of the isosceles trapezoid of the second connecting segment 33 (i.e., the taper of the second connecting segment 33) is 22.5 ± 0.25°.

[0043] With the above settings, since the difference between the angle between the two hypotenuses of the cross section of the first connecting segment 33 and the angle between the two hypotenuses of the cross section of the second connecting segment 33 is small (less than 8°), the transition angle on both sides of the connecting segment 33 between the first cutting segment 31 and the second cutting segment 32 is small, which allows for better control of the plasticity of the contact area 150 during stamping.

[0044] Specifically, the surface of the first rod 11 is provided with a fixing groove 111. Since the punch rod 1 is a columnar body, the fixing groove 111 facilitates the fixing of the entire punch rod 1 and allows pressure to be applied by an external device.

[0045] Specifically, the punch is made of eutectic graphite steel in one piece.

[0046] Using the above method, since the valve core and the side wall of the conical transition cavity 140 are in contact with the side wall of the third cavity 130, the contact contour between the valve sleeve 100 and the valve core will have a certain deviation, which will lead to unstable sealing of the assembly. By setting a first cutting section 31 and a second cutting section 32 on the punch, the taper on both sides of the connecting section 33 of the first cutting section 31 and the second cutting section 32 decreases from large to small in the direction of the first cutting section 31 to the second cutting section 32, and the connecting section 33 of the first cutting section 31 and the second cutting section 32 is made to contact the contact part 150, and pressure is applied to make the contact part 150 undergo plastic deformation of 0.01-0.02mm. After verification, it was found that the contour of the valve sleeve 100 sealing part (i.e., around the contact part 150) after plastic deformation by the punch can better fit with the valve core surface, thereby increasing the sealing performance.

[0047] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for increasing the sealing performance of a safety valve, characterized in that, Includes the following steps: A valve sleeve (100) for a safety valve is manufactured. The valve sleeve (100) includes an inner cavity that is fitted to the valve core. The inner cavity includes a first cavity (110), a second cavity (120), and a third cavity (130) arranged coaxially. A conical transition cavity (140) is provided between the second cavity (120) and the third cavity (130). A contact portion (150) is formed between the side wall of the conical transition cavity (140) and the side wall of the third cavity (130) to contact the valve core of the safety valve. The punch is coaxially arranged with the inner cavity. The punch includes a punch rod (1). One end of the punch rod (1) extends into an extension structure (2) with a gradually decreasing diameter and is connected to a cutting edge (3) through the extension structure (2). The cutting edge (3) includes a first cutting segment (31) and a second cutting segment (32) connected to the first cutting segment (31). Both the first cutting segment (31) and the second cutting segment (32) are tapered. The tapering on both sides of the connecting section (33) between the first cutting segment (31) and the second cutting segment (32) decreases from large to small in the direction from the first cutting segment (31) to the second cutting segment (32). When a punching force is applied axially to the punch, the connecting section (33) of the first cutting segment (31) and the second cutting segment (32) contacts the contact portion (150), causing plastic deformation in the contact portion (150) area. The amount of plastic deformation is 0.01-0.02 mm. After the plastic deformation is caused by the punch, the contour around the contact portion (150) of the valve sleeve (100) can better fit with the valve core surface, thereby increasing the sealing performance. The impact force ranges from 4 to 4.5 kN, and the axial length of the connecting section (33) is 0.3 ± 0.1 mm; The cross-section of the first cutting segment (31) and the cross-section of the second cutting segment (32) are both isosceles trapezoids. The angle between the two hypotenuses of the cross-section of the first cutting segment (31) is greater than the angle between the two hypotenuses of the cross-section of the second cutting segment (32). The angle between the two hypotenuses of the isosceles trapezoidal cross section of the first cutting segment (31) is 30.5 ± 0.25°; The angle between the two hypotenuses of the isosceles trapezoidal cross section of the second blade segment (32) is 22.5 ± 0.25°.

2. The method for increasing the sealing performance of a safety valve according to claim 1, characterized in that, The punch rod (1) includes a first rod body (11), and a second rod body (12) extends coaxially from one end of the first rod body (11). The extension structure (2) is located at the end of the second rod body (12) away from the first rod body (11). The diameter of the second rod body (12) is smaller than that of the first rod body (11), so that a step is formed between the first rod body (11) and the second rod body (12). The second rod body (12) extends into the second cavity (120) and is clearance-fitted with the second cavity (120).

3. The method for increasing the sealing performance of a safety valve according to claim 1, characterized in that, The cross-section of the extension structure (2) is an isosceles trapezoid.

4. The method for increasing the sealing performance of a safety valve according to claim 3, characterized in that, The angle between the two hypotenuses of the isosceles trapezoidal cross section of the extended structure (2) is 80±1°.

5. The method for increasing the sealing performance of a safety valve according to claim 2, characterized in that, The surface of the first rod (11) is provided with a fixing groove (111).

6. The method for increasing the sealing performance of a safety valve according to claim 1, characterized in that, The punch is made of eutectic graphite steel in one piece.

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