A fire protection butterfly valve

Abstract

The present invention discloses a fire fighting butterfly valve, which includes a valve plate, a valve body and a valve shaft. The sealing surface of the inner cavity of the valve body is an ellipsoidal sealing surface, and the sealing band of the inner cavity of the valve body is a sealing surface of an elliptical curved surface. The sealing band is an ellipsoidal spherical surface formed by a section of eccentric spherical crown line rotating around the central axis. The shaft end sealing surfaces at the upper and lower shaft ends of the valve plate are conical raised sealing surfaces. The present invention adopts a newly designed sealing pair. When the butterfly plate is closed, the sealing water line on the side of the valve plate spirally enters the elliptical sealing surface of the valve body at a small angle, and the interference extrusion amount of the valve plate rubber gradually increases from small to large, changing the disadvantage that the interference extrusion amount of the valve plate rubber formed by the spherical surface of the traditional inner cavity of the valve body does not change from the inlet to the outlet and the rubber wear is large, reducing the wear of the valve plate rubber sealing line and reducing the torque of the valve opening and closing.

Description

Technical Field

[0001] The present invention belongs to the technical field of butterfly valves, and particularly relates to a fire-fighting butterfly valve. Background Art

[0002] In the field of valve design, especially in the fire-fighting butterfly valves of the center-line wafer, clamp and lug types, among which for the center-line fire-fighting butterfly valves with the inner cavity sealing surface sprayed and the valve plate rubber-coated, there are mainly two shapes for the existing valve body sealing pair design: 1. The inner cavity through-diameter sealing band adopts a cylindrical flat sealing surface shape; 2. The inner cavity through-diameter sealing band adopts a spherical shape. There are also two sealing forms for the valve plate: 1. The valve plate adopts a combined shape design of end-cut chord and single water line; 2. The valve plate adopts a global spherical shape design.

[0003] The sealing of the center-line butterfly valve mainly depends on the interference fit between the butterfly plate and the rubber valve seat, relying on the elasticity of the rubber to achieve it. The above-mentioned technology is the most used design structure by domestic manufacturers of center-line rubber-sealed butterfly valves at present. The structure is simple and the product cost is low. However, due to the high sealing requirements of fire-fighting center-line butterfly valves, the sealing pressure is more than twice the design pressure. Especially for the international UL / FM fire-fighting butterfly valve certification, a strict high-pressure life sealing test is required. In the existing sealing pair design of the valve plate and the valve body, the sealing is ensured by increasing the interference amount, especially by increasing the interference amount at the ends of the upper and lower shaft holes of the valve plate to ensure the sealing during the high-pressure test. In actual use and certification tests, leakage is likely to occur at the ends of the upper and lower shafts of the valve plate and leakage caused by rubber fatigue aging of the two-side seals, thus reducing the sealing effect of the butterfly valve and shortening the service life of the butterfly valve product.

[0004] In summary, the current center-line fire-fighting butterfly valve has certain defects in the sealing pair design of the valve plate and the valve body, mainly in the relatively large design of the sealing interference amount of the valve plate rubber, resulting in insufficient valve plate life. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention provides a new type of sealing pair, which utilizes the advantages of a numerical control machining center to improve the sealing shape and principle of the valve body and the valve plate. Compared with the traditional machining of the valve body and the valve plate, there is a new innovation, and its sealing effect and service life are significantly better than those of the traditional center-line fire-fighting butterfly valve.

[0006] The present invention is realized as follows. A fire-fighting butterfly valve includes a valve plate, a valve body and a valve shaft, and is characterized in that: the sealing surface of the inner cavity of the valve body is an ellipsoidal sealing surface, the sealing band of the inner cavity of the valve body is a sealing surface of an elliptical curved surface, and the sealing band is an ellipsoidal spherical surface formed by a section of eccentric spherical crown line rotating around the central axis; the shaft end sealing surfaces at the upper and lower shaft ends of the valve plate are frustum-shaped raised sealing surfaces.

[0007] Preferably, the center of the sphere of the sealing band is located on a circle with a radius ranging from 1 / 2 through-diameter to 1 times the through-diameter centered on the center of the inner cavity of the valve body.

[0008] Preferably, the spherical radius of the sealing band of the valve body is 1 / 2 to 2 times the nominal diameter and is greater than the rotation radius of the valve plate, so that the valve plate is gradually screwed into the ellipsoidal sealing band of the valve body when being screwed in.

[0009] Preferably, the shaft end sealing band of the valve plate is a conical raised sealing surface, and the height m from the highest point of the raised part to the spherical radius SR is 0.6 - 1.2 mm, and the width b is 4 - 10 mm.

[0010] The sealing structure of the center line fire fighting butterfly valve of the present invention has the following advantages compared with the prior art:

[0011] 1. The structure of the present invention is simple. Through the elliptical curved surface of the sealing band in the valve body cavity, when the valve plate is screwed into the sealing band of the valve body, it forms a progressive screwing-in, protecting the rubber sealing band of the valve plate, changing the simple cylindrical and simple spherical sealing surfaces of the traditional center line butterfly valve, introducing a combined sealing surface of the two, and innovatively utilizing the progressive screwing-in principle of the cylindrical sealing surface and the self-sealing principle of the spherical sealing after the valve plate is pressed and floats, creating a new sealing form. The design of the present invention completely improves the disadvantages in the principle of the traditional single spherical sealing band of the valve body, that is, the problem that it is difficult to grasp the manual chamfering of the edge of the valve plate when it is screwed into the entrance of the sealing band, and the consistent interference change of the valve plate in the sealing band of the valve body, large torque, and increased floating torque of the valve plate. It also improves the traditional cylindrical sealing band form of the valve body, the large amount of valve body processing, and the problem of poor shaft end sealing. The present invention improves the performance of the center line butterfly valve product and the reliability of the seal, and extends the service life of the butterfly valve product.

[0012] 2. For the center line fire fighting butterfly valve provided by the present invention, the sealing surface of the valve plate is designed as a combination of conical raised parts at the upper and lower shaft ends and double-line sealing surfaces on both sides of the valve plate. The conical raised design at the upper and lower shaft ends effectively overcomes the influence of geometric dimension differences during the opening and closing of the shaft hole part corresponding to the cylindrical valve body sealing surface of the rubber-coated valve plate. The design of the present invention makes the cross-sectional shape of the sealing surface at the shaft end of the valve plate be a slope shape. When the shaft end of the valve plate is installed into the sealing band of the valve body, it is smooth and not easy to produce installation rejects, well solving the disadvantages of large interference and large wear in the shaft hole sealing of the traditional single spherical sealing band-shaped valve body, and more importantly, solving the disadvantages of uneven interference in the vertical and horizontal directions at the upper and lower shaft holes of the rubber valve plate and large rubber aging caused by the change of the interference during opening and closing in the traditional cylindrical sealing band of the valve body. The newly improved valve body and valve plate design improve the rationality and reliability of the valve seal, thereby extending the service life of the butterfly valve product.

[0013] In summary, the present invention relates to a new sealing pair structure applied to a fire fighting butterfly valve. Utilizing the advantages of a CNC machining center, it improves the sealing shape and principle of the valve body and valve plate, has new innovations compared with the traditional valve body and valve plate processing, and its sealing effect is better than that of the traditional fire fighting butterfly valve. Description of the Drawings

[0014] Figure 1 is the structural schematic diagram of the present invention;

[0015] Figure 2 is Figure 1 the A-A cross-sectional view in

[0016] Figure 3 is Figure 1 the B-B cross-sectional view in

[0017] Figure 4 is Figure 3 the enlarged view of part I in

[0018] Figure 5 is the structural schematic diagram of the valve body;

[0019] Figure 6 is Figure 5 the enlarged view of II in

[0020] Figure 7 is the schematic diagram of the raised round platform at the shaft end of the valve plate;

[0021] Figure 8 is the diagram of the horizontal plane sealing state of the valve plate when the valve plate is closed in the shaft end sealing area;

[0022] Figure 9 is the diagram of the vertical sealing state of the valve plate when the valve plate is closed in the shaft end sealing area;

[0023] Figure 10 is the diagram of the horizontal plane sealing state of the valve plate when the valve plate is closed in the shaft end sealing area of the traditional fire fighting butterfly valve;

[0024] Figure 11 is the diagram of the vertical sealing state of the valve plate when the valve plate is closed in the shaft end sealing area of the traditional fire fighting butterfly valve. Detailed implementation manners

[0025] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] The present invention relates to a new type of sealing pair structure applied to a fire fighting butterfly valve. Utilizing the advantages of a numerical control machining center, the sealing shape and principle of the valve body and valve plate are improved. Compared with the traditional machining of the valve body and valve plate, there is a new innovation, and its sealing effect is better than that of the traditional fire fighting butterfly valve. The specific structure is as follows.

[0027] Please refer to Figures 1 to 6; A fire butterfly valve, comprising a valve plate 1, a valve body 2 and a valve shaft 3. The sealing surface of the sealing belt in the inner cavity of the valve body is an ellipsoidal sealing surface, and the sealing belt is an ellipsoidal spherical surface formed by rotating a section of eccentric spherical crown line around the central axis; when the valve plate is screwed into the sealing belt of the valve body, a progressive screwing-in is formed to protect the rubber sealing belt of the valve plate, changing the simple cylindrical and simple spherical sealing surfaces of the traditional center-line butterfly valve, introducing a combined sealing surface of the two, and innovatively utilizing the progressive screwing-in principle of the cylindrical sealing surface and the self-sealing principle of the spherical surface sealing after the valve plate is pressed and floats, creating a new sealing form. The present invention improves the performance of the center-line butterfly valve product, the reliability of the seal, and extends the service life of the butterfly valve product.

[0028] The center of the radius SR of the ellipsoidal sealing surface has an eccentricity e (0.1 - 1 times the size of the radius SR1 of the valve plate) from the processing rotation center. When corresponding to the rotation radius SR1 of the valve plate being screwed into the inlet of the sealing belt of the valve body, there is a spacing e1 (0.2 - 0.4 mm). Please refer to Figure 5 and Figure 6 , ensuring that the edge of the valve plate is not cut when entering the sealing belt. When the valve plate rotates and squeezes in during valve closing, the interference deformation of the rubber at the edge of the valve plate gradually increases. When the valve opens, the valve plate can gradually disengage from the seal. This design completely improves the disadvantages in the principle of the traditional single spherical sealing belt of the valve body, that is, the problem that it is difficult to grasp the manual chamfering of the edge of the valve plate when it is selected into the inlet of the sealing belt and the interference change of the valve plate in the sealing belt of the valve body is consistent, with large torque and an increase in the floating torque of the valve plate. It also improves the traditional cylindrical sealing belt form of the valve body, the large amount of valve body processing, and the problem of poor shaft end sealing.

[0029] The shaft end sealing belt of the valve plate is a conical raised sealing surface. See Figure 7 , and the height m from the highest point of the raise to the spherical radius SR is 0.6 - 1.2 mm, and the width b is 4 - 10 mm. This design makes the cross-sectional shape of the interference amount between the sealing surface at the shaft end of the valve plate and the valve body a slope shape. See Figure 8 (cross-section of the shaft hole during valve closing) and Figure 9 (vertical section of the shaft hole during valve closing). During valve closing, the maximum interference amounts b1 and b3 of the shaft end of the valve plate in the cross-section and vertical section of the shaft hole are 0.9 - 1.5 mm. From the maximum interference amounts b1, b3 of about 1.8 mm inside the raised platform to 1.2 mm of b2 outside (cross-section of the shaft hole during valve closing), and the outermost interference amount of 0.2 mm in the vertical section of the shaft hole during valve closing, a slope-shaped cross-section with an angle a1 and an angle a2 (4 - 10 degrees) is formed; making it smooth and easy to install the valve plate into the sealing belt of the valve body, not easily generating installation rejects, and well solving the problem that the interference amount between the traditional single spherical sealing belt-shaped valve body and the sealing surface of the valve plate shaft hole is consistent. See Figure 10 and Figure 11, the maximum and minimum body plate rubber interference amounts are both dimension b, solving the disadvantages of large shaft-hole sealing interference and large wear, and further solving the disadvantages of large rubber aging caused by uneven interference amounts in the vertical and horizontal directions at the upper and lower shaft holes of the traditional valve body cylindrical sealing band and the change of the opening and closing interference amount. The newly improved valve body and valve plate design improves the rationality and reliability of valve sealing, thereby extending the service life of the butterfly valve product.

[0030] Preferably, see Figure 3 , the center of the spherical surface of the ellipsoidal sealing band of the valve body is located on an eccentric band with a radius of e centered on the center of the inner cavity of the valve body, and its size is 0.1-1 times the radius SR1 of the valve plate; there is a spacing e1 (0.2-0.4 mm) when the valve plate rotates into the inlet of the valve body sealing band corresponding to the rotation radius SR1.

[0031] Preferably, the shaft end sealing band of the valve plate is a frustum-shaped raised sealing surface, see Figure 4 , the height m from the highest point of the raised part to the spherical radius SR is 0.6-1.2 mm, and the width b is 4-10 mm.

[0032] In summary, the present invention combines an elliptical curve sealing surface of the valve body and a frustum-shaped raised sealing surface of the shaft end sealing surface of the valve plate to form a brand-new sealing pair; when the butterfly plate is closed, the side sealing water line spirals into the elliptical sealing surface of the valve body at a small angle, changing the design form of the traditional inner cavity cylindrical surface or the inner cavity spherical surface of the valve body, reducing the wear of the double water line rubber sealing line of the valve plate, reducing the torque of valve opening and closing. At the same time, when the valve plate is pressed and floats, the valve plate sealing band moves up and down along the elliptical spherical surface, getting tighter and tighter when closing, increasing the self-sealing effect of the valve plate itself, increasing the reliability of valve sealing, and thus extending the service life of the butterfly valve product.

[0033] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A fire butterfly valve, comprising a valve plate, a valve body and a valve shaft, characterized in that: the sealing surface of the inner cavity of the valve body is an ellipsoidal sealing surface, the sealing belt of the inner cavity of the valve body is a sealing surface of an elliptical curved surface, and the sealing belt is an ellipsoidal spherical surface formed by a section of eccentric spherical crown line rotating around the central axis; the shaft end sealing surfaces at the upper and lower shaft ends of the valve plate are conical raised sealing surfaces; the center of the sphere of the sealing belt is located on a circle with a radius ranging from 1 / 2 of the nominal diameter to 1 times the nominal diameter centered on the center of the inner cavity of the valve body; the spherical radius of the sealing belt of the valve body ranges from 1 / 2 of the nominal diameter to 2 times the nominal diameter, and is greater than the rotation radius of the valve plate, so that the valve plate is gradually screwed into the ellipsoidal spherical sealing belt of the valve body when screwed in; the valve plate shaft end sealing belt is a conical raised sealing surface, and the height m from the highest point of the raise to the radius SR of the ellipsoidal sealing surface is 0.6 - 1.2 mm, and the width b is 4 - 10 mm; the center of the circle of the ellipsoidal sealing surface radius SR has an eccentricity e with the machining rotation center; there is a spacing e1 when corresponding to the valve plate rotation radius SR1 being screwed into the inlet of the valve body sealing belt.

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