Integral disc for hard sealing triple offset butterfly valve and method for manufacturing same

Abstract

This invention provides an integral butterfly plate for a hard-seal triple eccentric butterfly valve and its processing method. The integral butterfly plate includes a butterfly plate body and a sealing surface integrally connected to the butterfly plate body. The processing method of the integral butterfly plate is as follows: a sealing material is sprayed or welded onto the butterfly plate body to form a sealing surface, and the sealing surface and the butterfly plate body are integrally processed to form an integral butterfly plate. Compared with traditional hard-seal butterfly plates, the integral butterfly plate overcomes the disadvantages of traditional structures, such as easy loosening, poor erosion resistance, and easy damage to the sealing surface leading to failure. It also meets harsh working conditions such as high temperature, low temperature, high corrosion, high viscosity, solid particles, and high erosion force, improving the sealing stability and service life of hard-seal butterfly valves. It reduces the number of parts and components while avoiding the drawbacks of using special materials for the sealing ring as a whole, saving production costs and enabling mass production.

Description

Technical Field

[0001] This invention relates to the field of butterfly valve processing, specifically to an integral butterfly plate of a hard-seal triple eccentric butterfly valve and its processing method. Background Technology

[0002] Currently, in the use of triple-eccentric butterfly valves, especially hard-seal triple-eccentric butterfly valves, the butterfly plate, sealing ring, gasket, and pressure plate ring are all fastened together with screws. The butterfly plate and sealing ring are two separate, independent parts. This hard-seal butterfly plate structure leads to the butterfly plate sealing ring being prone to loosening under harsh operating conditions, not being resistant to erosion, and the sealing surface being easily damaged. The all-metal hard-seal triple-eccentric integral butterfly plate and sealing surface are difficult to manufacture, costly, and have limited selection, thus restricting further performance improvements of all-metal hard-seal butterfly valves and greatly limiting their application. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings and deficiencies of existing technologies and to provide a rigid-seal triple-eccentric butterfly valve with an integral butterfly plate and its processing method, thus solving the processing difficulties of the rigid-seal triple-eccentric integral butterfly plate. The technical solution adopted by this invention is as follows:

[0004] A hard-seal triple eccentric butterfly valve features an integral butterfly plate, formed by integral casting and forging. The sealing surface is directly machined onto the butterfly plate, forming an all-metal hard-on-hard sealing pair. The sealing surface is formed by spraying or welding Stellite alloy, nickel-based alloy, or other wear-resistant and corrosion-resistant metals. The machining method of the integral butterfly plate specifically includes the following steps:

[0005] Step 1: Using a slant plate and clamping tools, perform rough machining of the disc body on a lathe, and adjust the required sealing surface thickness according to the sealing material, reserving the sealing surface thickness during rough machining;

[0006] Step 2: On the rough-machined butterfly plate body, according to the properties of the sealing material, the sealing material is sprayed or welded onto the three eccentric cone surfaces of the rough-machined butterfly plate body to form a sealing surface.

[0007] Step 3: Make the sealing surface width b, calculate the center line of the eccentricity c, control the turning depth, and make the width b distributed across the center line c. Make the sealing force act on the optimal sealing position calculated according to the theoretical design. At the same time, the width b can be set according to the required sealing specific pressure of the sealing material, so that the friction torque of the sealing pair is small and the sealing self-locking is possible.

[0008] Step 4: Using a slant plate and clamping tools, perform finishing machining of the integral disc plate on a lathe; turn the plate and leave a grinding allowance of 0.1-0.3mm; after turning, grind the sealing surface to the required size, and the surface finish of the sealing surface Ra≤0.1μm to meet the requirements of achieving zero leakage level for hard seal.

[0009] Preferably, in step one, the reserved sealing surface thickness is 1.5-2.5mm when the sealing material is a welding material and 0.4-0.6mm when the sealing material is a spraying material.

[0010] As a preferred option, in step two, to ensure an appropriate machining allowance for the sealing material, the weld overlay thickness is ≥4mm or the spray coating thickness is ≥0.8mm.

[0011] Preferably, in step two, the sealing material is applied evenly to the triple eccentric cone surface (i.e., the position that forms a seal with the valve body) of the rough-machined disc body using supersonic spraying or robotic welding. After finishing, the effective thickness of the sealing material is uniform on the disc body, ensuring that the chemical composition and physical properties of the overall disc sealing surface meet the technical requirements.

[0012] As a preferred option, step three involves the following specific steps:

[0013] S1. Set up a process boss for clamping, clamp and adjust the center position of the disc body, and machine the shaft hole surface of the disc body. The specific steps are as follows:

[0014] ① Locate four points A, B, C, and D on the center line of the major and minor axes of the butterfly plate and the direction of the shaft hole on the shaft hole surface, and all four points are 2mm off-center from the center line of the butterfly plate body;

[0015] ②The first turning diameter is determined by points A, B, and D;

[0016] ③The second turning diameter is determined by points B, C, and D;

[0017] ④ With the butterfly plate body as the center, turn the plate with a turning radius of point A; after the three turning operations, the sealing surface protrudes 2-3mm from the butterfly plate body.

[0018] S2. Clamp the shaft hole surface of the integral butterfly plate, and machine the back of the integral butterfly plate. Specifically, first remove the process boss, and machine the taper based on the sealing surface of the short shaft end of the integral butterfly plate protruding 2mm from the butterfly plate body. After turning, make the sealing surface protrude 2-3mm from the butterfly plate body.

[0019] The processing method for preparing an integral butterfly valve provided by this invention does not require additional special equipment and tooling fixtures. It can be processed on a conventional CNC vertical or horizontal CNC lathe using a slant plate and clamping tools for processing conventional triple eccentric butterfly valves, saving costs and processing time. Furthermore, the sealing surface width b can be reasonably designed according to the different required specific pressures of different hard sealing materials to meet the sealing specific pressure requirements of the all-metal hard sealing pair, enabling the all-metal hard sealing pair to achieve zero leakage. This makes the triple eccentric hard sealing butterfly valve with an integral butterfly valve suitable for pipelines with high sealing requirements.

[0020] The beneficial effects of the present invention are as follows: (1) Compared with the traditional hard-seal butterfly plate, the integral butterfly plate overcomes the disadvantages of the traditional structure being easy to loosen, not resistant to erosion, and the sealing surface being easily damaged and failing; (2) The integral butterfly plate meets the harsh working conditions such as high temperature, low temperature, high corrosion, high viscosity, solid particles, and large erosion force, which improves the sealing stability and service life of the hard-seal butterfly valve; (3) The sealing surface is directly processed on the butterfly plate, which reduces the number of parts and components while avoiding the disadvantage of using special materials for the sealing ring as a whole, which greatly saves production costs; This enables the mass production of this high-performance integral butterfly plate and broadens the application range of the hard-seal triple eccentric butterfly valve. Attached Figure Description

[0021] 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 only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0022] Figure 1 This is a schematic diagram of a traditional hard-seal structure.

[0023] Figure 2 This is a schematic diagram of the overall hard-sealed butterfly plate structure of the present invention;

[0024] Figure 3 Schematic diagram of the machining fixtures for the inclined plate and the disc plate;

[0025] Figure 4 A schematic diagram showing the location of the integral butterfly plate sealing material overlay welding or spraying;

[0026] Figure 5 A schematic diagram showing the machining locations at various points on the integral butterfly plate;

[0027] Figure 6 A schematic diagram showing the location of the process boss;

[0028] Figure 7 A schematic diagram showing the clamping of an integral butterfly plate on a slant plate and butterfly plate machining fixture;

[0029] In the diagram, 1-conventional butterfly plate, 2-gasket, 3-metal sealing ring, 4-pressure plate, 5-screw, 6-integral butterfly plate, 61-first process boss, 62-second process boss, 601-long shaft end, 602-short shaft end, 7-hard sealing surface, 8-sloping plate, 9-butterfly plate tooling, 10-butt welding or spraying sealing material; 11-butterfly plate center, 101-first rotation diameter, 102-second rotation diameter, 103-rotation radius. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0032] The directional and positional terms used in this invention, such as "up," "down," "front," "back," "left," "right," "inner," "outer," "top," "bottom," and "side," are merely for reference to the accompanying drawings. Therefore, the directional and positional terms used are for illustrating and understanding this invention, and not for limiting the scope of protection of this invention.

[0033] Figure 1 This is a schematic diagram of a conventional hard-seal butterfly plate, which includes a metal sealing ring 3, a gasket 2, and a pressure plate 4. See the appendix for embodiments of the present invention. Figure 2-7 ,like Figure 2 As shown, the integral butterfly plate 6 provided by the present invention is formed by integral casting and integral forging, and the sealing surface 7 is directly machined on the butterfly plate body; it adopts an all-metal hard-on-hard sealing pair, and the sealing surface 7 is formed by directly spraying or overlaying Stellite alloy, nickel-based alloy and other sealing materials that meet different working conditions on the butterfly plate body.

[0034] like Figure 3-7 As shown, the processing steps of the integral triple-eccentric hard-seal butterfly plate of the present invention are as follows:

[0035] Step 1: Using a slant plate and clamping tools for machining conventional triple eccentric butterfly plates, perform rough machining of the integral butterfly plate on a standard CNC vertical or horizontal CNC lathe. Based on the required thickness of the welding or spraying sealing material (generally about 2mm for welding and about 0.5mm for spraying), allow for the thickness of the sealing surface during rough machining, and machine to the dimensions before welding or spraying.

[0036] Step two: On the rough-machined disc body, depending on the properties of the welding material, apply sealing material evenly to the triple eccentric cone surface (i.e., the position that forms a seal with the valve body) using supersonic spraying or robotic welding. To ensure adequate machining allowance for the sealing material, it is recommended that the welding thickness be ≥4mm and the spraying thickness be ≥0.8mm (grinding).

[0037] Step 3: Machining the sealing surface to a width of b, calculating the centerline of the eccentricity c, and controlling the turning depth to ensure that the width b is distributed along the eccentric centerline c. The specific operations are as follows:

[0038] (1) In Figure 6 The first process boss 61 and the second process boss 62 are shown in the welding and clamping positions (those skilled in the art can arrange an appropriate number according to the diameter). The center of the disc body is adjusted by clamping and adjusting, and the disc shaft hole surface is machined. The steps for machining this surface are: ① Marking lines on this surface to find the correct position. Figure 5 Points A, B, C, and D are shown, all 2mm off-center from the centerline of the disc; ② The first turning diameter 101 is determined by points A, B, and D and machined; ③ The second turning diameter 102 is determined by points B, C, and D and machined; ④ With the disc as the center, the turning radius 103 is taken from point A and machined. After three turning operations, the sealing surface protrudes 2-3mm from the disc body.

[0039] (2) Clamp the shaft hole surface of the integral butterfly plate and process the back of the integral butterfly plate: First remove the first process boss 61 and the second process boss 62. With the sealing surface of the short shaft end 602 protruding 2mm from the outer conical surface of the butterfly plate as the reference (i.e. point A), process the taper. After turning, the sealing surface can protrude 2-3mm from the butterfly plate body.

[0040] Step four: Using a slant plate and clamping tools from a conventional triple eccentric butterfly plate machining process, perform the integral triple eccentric butterfly plate finishing on a standard CNC vertical or horizontal CNC lathe. Turn the plate to the sealing surface, leaving approximately 0.2mm for grinding. After turning, grind the sealing surface to the required dimensions and surface finish. The surface finish Ra of the hard seal surface must reach at least 0.1μm to ensure zero leakage in the triple eccentric hard seal pair.

[0041] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for processing the integral butterfly plate of a hard-seal triple eccentric butterfly valve, characterized in that: The integral butterfly plate (6) includes a butterfly plate body and a sealing surface (7) integrally connected to the butterfly plate body; The processing method of the integral butterfly plate (6) is as follows: a sealing material is sprayed or welded onto the butterfly plate body to form a sealing surface (7), and the sealing surface (7) and the butterfly plate body are integrally processed to form an integral butterfly plate (6), which is specifically divided into the following steps: Step 1: Use the slant plate (8) and clamping tools to perform rough machining of the disc body on the lathe, and adjust the required sealing surface thickness according to the sealing material, and reserve the sealing surface thickness during rough machining; Step 2: On the rough-machined butterfly plate body, according to the properties of the sealing material, the sealing material is sprayed or welded onto the three eccentric cone surfaces of the rough-machined butterfly plate body to form a sealing surface (7). Step 3: Make the width of the sealing surface (7) b, calculate the center line of the eccentricity c, control the turning depth, and make the width b distributed in the middle of the eccentricity center line c; Step 4: Using a slant plate (8) and clamping tools, perform finishing on the integral disc plate on a lathe; perform turning and leave a grinding allowance of 0.1-0.3mm; after turning, grind the sealing surface to the required size, and the surface finish of the sealing surface Ra≤0.1μm; In step three, the specific operation is as follows: S1. Set up a clamping process boss (61), clamp and adjust the center position of the butterfly plate body, and machine the shaft hole surface of the butterfly plate body. The specific steps are as follows: ① Locate four points A, B, C, and D on the center lines of the long and short axes and the direction of the shaft hole on the surface of the shaft hole, and each of the four points is 2mm away from the center line of the butterfly plate body. ②The first turning diameter (101) is determined by points A, B, and D; ③The second turning diameter (102) is determined by points B, C, and D; ④ With the butterfly plate body as the center, turn the plate to point A with a radius of rotation (103) and then turn it. After three turning operations, make the sealing surface (7) protrude 2-3 mm from the butterfly plate body. S2. Clamp the shaft hole surface of the integral butterfly plate (6) and process the back of the integral butterfly plate. Specifically, remove the process boss (61) first, and process the taper based on the sealing surface of the short shaft end (602) of the integral butterfly plate (6) protruding 2mm from the butterfly plate body. After turning, make the sealing surface (7) protrude 2-3mm from the butterfly plate body.

2. The method for processing the integral butterfly plate of a hard-seal triple eccentric butterfly valve according to claim 1, characterized in that: In step one, the reserved thickness of the sealing surface is specifically 1.5-2.5mm when the sealing material is a weld overlay material and 0.4-0.6mm when the sealing material is a spray coating material.

3. The method for processing the integral butterfly plate of a hard-seal triple eccentric butterfly valve according to claim 1, characterized in that: In step two, to ensure adequate machining allowance for the sealing material, the weld overlay thickness should be ≥4mm or the spray coating thickness should be ≥0.8mm.

4. The method for processing the integral butterfly plate of a hard-seal triple eccentric butterfly valve according to claim 1, characterized in that: In step two, the sealing material is applied evenly to the three-eccentric cone surface of the rough-machined disc body using supersonic spraying or robotic welding.

5. A method for processing the integral butterfly plate of a hard-seal triple eccentric butterfly valve according to any one of claims 1-4, characterized in that: The sealing materials include Stellite alloy and nickel-based alloys.

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