Built-in concave-convex wheel limiting structure for three / four eccentric butterfly valve

Abstract

The invention belongs to the technical field of valves, and relates to a built-in concave-convex wheel limiting structure for a three / four eccentric butterfly valve, which comprises a valve body, a valve shaft is rotatably arranged in a shaft hole of the valve body, a valve plate is mounted on the valve shaft, and the valve shaft can drive the valve plate to rotate to realize opening and closing control of the valve. The check valve is characterized in that concave wheels which are integrally cast and formed are respectively arranged on the upper part and the lower part of the valve body runner close to the shaft hole, and each concave wheel is provided with a first side arc surface; an upper shaft shell and a lower shaft shell of the valve plate are respectively provided with a cam which is integrally cast and formed, the cam is provided with a second side arc surface, the first side arc surface is a limiting surface for preventing the valve from being closed excessively, and the second side arc surface and the first side arc surface can achieve linear contact limiting. The concave-convex wheel limiting structure is accurate in limiting, good in sealing performance and high in reliability.

Description

Technical Field

[0001] The invention belongs to the technical field of valves and relates to a built-in concave cam limiting structure for a three- or four-eccentric butterfly valve. Background Art

[0002] The three-eccentric butterfly valve and the four-eccentric butterfly valve evolved from the double-eccentric butterfly valve, which evolved from the line seal of the original double-eccentric butterfly valve to the face seal. The valve can be sealed by providing a certain specific pressure value to the sealing surface by relying on the torque value of the actuator. The output torque values ​​of different actuators vary. In particular, some single-acting actuators with springs have a large difference in the output torque values ​​for opening and closing. When selecting, in order to meet the torque when opening, the closing torque of the actuator greatly exceeds the closing torque required by the valve itself. When the valve is closed, the medium pressure difference acts on the valve plate and is transmitted to the sealing surface, which also increases a certain specific pressure on the sealing surface. Excessive sealing specific pressure will cause excessive extrusion of the sealing surface on the sealing ring, indirectly causing the warping and deformation of the sealing ring, and ultimately affecting the sealing performance and service life of the valve.

[0003] Three / four eccentric butterfly valves require a mechanical closing limit to ensure the normal and safe use of the valve. Some of the actuators selected for the valve also have their own travel limit devices. For example, the gear rack actuator uses a circular arc segment on the rotating shaft and the end face of the hexagonal bolt to form a limit, but due to the problem of the force angle, the hexagonal bolt is prone to bending and other phenomena, which is unreliable; or the actuator needs to be turned for installation on site. When the fasteners connecting the actuator and the valve are loosened and then tightened, the relationship between the actuator's limit mechanism and the valve seal position has become uncertain.

[0004] The three / four eccentric butterfly valve usually adopts the integrated structure of valve seat and valve body, and the overall rigidity of valve seat is good. The valve seat sealing surface is processed by rotation around the eccentric center line of the angle, and the switch position direction in the inner cavity of the valve body belongs to the processing rotation area. It is impossible to use the measures such as setting the limit step in the inner cavity of the valve body as a whole to mechanically limit the valve plate and sealing surface. Summary of the invention

[0005] In view of the above problems, the present invention provides a built-in concave cam limiting structure for a three-eccentric / four-eccentric butterfly valve. The concave cam limiting structure has precise limiting, good sealing performance and high reliability.

[0006] According to the technical solution of the present invention: a built-in concave cam limiting structure for a three / four eccentric butterfly valve includes a valve body, a valve shaft is rotatably arranged in the shaft hole of the valve body, a valve plate is installed on the valve shaft, and the valve shaft can drive the valve plate to rotate to realize the opening and closing control of the valve, characterized in that: the upper and lower parts of the valve body flow channel are respectively provided with integrally cast concave wheels near the shaft hole, and the concave wheels have a first side arc surface; The upper and lower shaft shells of the valve plate are respectively provided with integrally cast cams, the cams have a second side arc surface, the first side arc surface is a limit surface to prevent the valve from being over-closed, and the second side arc surface and the first side arc surface can achieve line contact limit.

[0007] As a further improvement of the present invention, the center line of the first side arc surface, the center line of the second side arc surface and the center line of the valve shaft are arranged in a triangle, and the radius of the first side arc surface is greater than the radius of the second side arc surface.

[0008] As a further improvement of the present invention, the valve shaft can drive the valve plate to rotate clockwise, and during the valve closing process, the cam and the concave wheel are in a non-contact state; when the valve shaft rotates 90° clockwise and the valve is closed, the second side arc surface and the first side arc surface are instantly in line contact and overlap.

[0009] As a further improvement of the present invention, both the first side arc surface and the second side arc surface are built-up with hard alloy.

[0010] The technical effects of the present invention are as follows: the present invention has a novel structure, and the concave and cam are cast with the valve body and valve plate respectively, which solves the problem of overlap between the stop block position and the valve seat processing area, and the limit is precise. The contact surface of the valve plate cam and the valve body concave wheel in the present invention is locally hardened to form a rigid limit, improve the limit surface strength and wear resistance, and extend the service life of the valve. The valve plate cam and valve body concave wheel in the present invention can not only achieve the limit function, but also enhance the sealing effect of the valve. The present invention can form a double limit guarantee with the mechanical limit of the actuator, and has high safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the present invention.

[0012] Figure 2 for Figure 1 A partial enlarged view of point A in the middle.

[0013] Figure 3 for Figure 1 Middle BB section view.

[0014] Figure 4 It is a schematic diagram of the matching between the first side arc surface R1 and the second side arc surface R2. DETAILED DESCRIPTION

[0015] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0016] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. The described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0017] Figure 1-4 The valve body 1 includes a cam 1.1, a sealing ring 2, a valve plate 3, a cam 3.1, a valve shaft 4, a first side arc surface R1, a second side arc surface R2, a pin 5 and the like.

[0018] like Figure 1-4 As shown, the present invention is a built-in concave cam limiting structure for a three / four eccentric butterfly valve, comprising a valve body 1, a valve shaft 4 is rotatably arranged in the axial hole of the valve body 1, a valve plate 3 is installed on the valve shaft 4, the valve shaft 4 can drive the valve plate 3 to rotate, and realize the opening and closing control of the valve, and the upper and lower parts of the flow channel of the valve body 1 are respectively provided with integrally cast concave wheels 1.1 near the axial hole, and the concave wheel 1.1 has a first side arc surface R1.

[0019] The upper and lower shaft shells of the valve plate 3 are respectively provided with an integrally cast cam 3.1, the cam 3.1 has a second side arc surface R2, the first side arc surface R1 is a limit surface to prevent the valve from being over-closed, and the second side arc surface R2 and the first side arc surface R1 can achieve line contact limit.

[0020] The center line of the first side arc surface R1 , the center line of the second side arc surface R2 and the center line of the valve shaft 4 are arranged in a triangle, and the radius of the first side arc surface R1 is greater than the radius of the second side arc surface R2 .

[0021] The valve shaft 4 can drive the valve plate 3 to rotate clockwise. During the valve closing process, the cam 3.1 and the cam wheel 1.1 are in a non-contact state; when the valve shaft 4 rotates 90 degrees clockwise and the valve is closed, the second side arc surface R2 and the first side arc surface R1 are instantly in line contact and coincide with each other, and the R1 value is a negative tolerance, and the R2 value is a positive tolerance; that is, the cam 3.1 adopts a positive tolerance and the cam wheel 1.1 adopts a negative tolerance, which is an interference fit, ensuring that when the valve shaft rotates 90 degrees clockwise, the cam wheel 1.1 and the cam 3.1 are in full contact, the cam wheel and the cam are squeezed tighter, and the limiting is more effective.

[0022] The surfaces of both the first side arc surface R1 and the second side arc surface R2 are built-up with cemented carbide.

[0023] like Figure 1-4As shown, when the present invention is working, the valve shaft 4 drives the valve plate 3 to rotate clockwise around the center line of the valve shaft 4. During the process of closing the valve, due to the existence of eccentricity, the cam 3.1 and the cam wheel 1.1 are in a non-contact state. When the valve shaft 4 rotates 90° clockwise to close the valve, the second side arc surface R2 of the cam 3.1 and the first side arc surface R1 of the cam wheel 1.1 are instantly in contact, and the line contact coincides, and the contact point on the same cross section and the center of the circle of R1 and R2 are collinear. This position is the maximum angle position that the cam 3.1 can rotate. If the valve shaft 4 continues to rotate, the cam 3.1 is limited by the cam wheel 1.1 and approaches the valve seat 1.2, thereby pushing the sealing ring 2 to close to the valve seat 1.2, while limiting the position, promoting the sealing of the valve. The valve plate 3 and the valve shaft 4 are fixedly connected by a pin 5.

[0024] like Figure 1-4 As shown, the first side arc surface R1 of the cam 1.1 and the second side arc surface R2 of the cam 3.1 are both welded with hard alloy to improve the strength of the limiting surface, increase the wear resistance and service life.

[0025] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A built-in concave cam limiting structure for a triple / quadruple eccentric butterfly valve, comprising a valve body (1), a valve shaft (4) rotatably arranged in an axial hole of the valve body (1), a valve plate (3) mounted on the valve shaft (4), the valve shaft (4) being capable of driving the valve plate (3) to rotate, thereby realizing opening and closing control of the valve, characterized in that: Integrally cast concave wheels (1.1) are respectively provided at the upper and lower parts of the flow channel of the valve body (1) near the shaft hole, and the concave wheel (1.1) has a first side arc surface (R1); An integrally cast cam (3.1) is respectively provided at the upper and lower shaft shells of the valve plate (3); the cam (3.1) has a second side arc surface (R2); the first side arc surface (R1) is a limit surface for preventing the valve from being over-closed; the second side arc surface (R2) and the first side arc surface (R1) can achieve line contact limit.

2. The built-in concave cam limiting structure for a triple / quadruple eccentric butterfly valve according to claim 1, characterized in that: The center line of the first side arc surface (R1), the center line of the second side arc surface (R2) and the center line of the valve shaft (4) are arranged in a triangle, and the radius of the first side arc surface (R1) is greater than the radius of the second side arc surface (R2).

3. The built-in concave cam limiting structure for a triple / quadruple eccentric butterfly valve according to claim 1, characterized in that: The valve shaft (4) can drive the valve plate (3) to rotate clockwise, and during the valve closing process, the cam (3.1) and the cam wheel (1.1) are in a non-contact state; when the valve shaft (4) rotates 90° clockwise and the valve is closed, the second side arc surface (R2) and the first side arc surface (R1) are in instantaneous line contact and overlap.

4. The built-in concave cam limiting structure for a triple / quadruple eccentric butterfly valve according to claim 1, characterized in that: The surfaces of both the first side arc surface (R1) and the second side arc surface (R2) are built-up with hard alloy.

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