Zero-leakage corrugated pipe gate valve

Abstract

The utility model relates to a zero-leakage corrugated pipe gate valve which comprises a valve body, a valve seat, a valve cover, a valve rod, a gate plate, a support and a transmission mechanism, a corrugated pipe sealing device is arranged between the valve rod and the valve cover, and the corrugated pipe sealing device is composed of a corrugated pipe, a sealing gasket and a positioning ring. The device is characterized in that a telescopic isolation device is arranged between the sealing gasket on the periphery of the corrugated pipe and the positioning ring, and the telescopic isolation device is composed of an upper isolation sleeve, a middle isolation sleeve and a lower isolation sleeve. The corrugated pipe is isolated from a medium in a sealed mode, medium impurities are prevented from adhering into corrugations of the corrugated pipe to affect the telescopic performance of the corrugated pipe and abrading and damaging the corrugated pipe, the use reliability of the corrugated pipe is improved, zero leakage of a middle cavity is achieved, and the corrugated pipe has the advantages of being reliable in sealing performance, long in service life and the like. The control valve is suitable for working conditions of poisonous, harmful, explosive and other dangerous media.

Description

Technical Field

[0001] The utility model belongs to the field of valves, and in particular relates to a bellows sealed gate valve. The utility model is suitable for control valves of pipelines containing toxic, harmful, explosive and other dangerous media. Background Art

[0002] The gate valve is one of the main valve types commonly used in media conveying pipelines. Its structure consists of a valve body, a valve cover, a valve seat, a valve stem, a gate and a transmission mechanism. Sealing surfaces that cooperate with the valve seat are provided on both sides of the gate, and the upper end is connected to the lower end of the valve stem. The upper end of the valve stem passes through the valve cover and is connected to the transmission mechanism on the bracket. A packing sealing device is arranged between the valve stem and the valve cover to achieve sealing of the middle cavity. However, during the frequent movement of the valve stem, the packing is easily worn and causes leakage in the middle cavity. Therefore, in order to improve the sealing performance of the middle cavity, a bellows sealing device is arranged between the valve stem and the valve cover to form a bellows gate valve structure, so as to achieve zero leakage in the middle cavity and prevent toxic, harmful, explosive and other dangerous media from leaking to the outside world and causing safety accidents. However, the bellows component of the existing bellows gate valve is in direct contact with the medium in the valve cavity, and impurities in the medium are easily accumulated in the corrugated space of the bellows. Especially when used in working conditions with particles, fibers, and easy-to-crystallize media, the corrugated space of the bellows is easily blocked, causing the bellows to lose its expansion and contraction performance, and even causing the bellows to wear and damage, resulting in obstruction of valve opening and closing and leakage of the middle cavity seal. Summary of the invention

[0003] The utility model aims to provide a bellows gate valve with a zero leakage which is isolated from a medium and can avoid clogging and abrasion of the bellows by impurities in the medium, thereby improving the reliability of the bellows and providing a bellows gate valve with reliable sealing performance and long service life.

[0004] The technical solution to realize the utility model is:

[0005] A zero-leakage bellows gate valve, comprising a valve body, a valve seat, a valve cover, a valve stem, a gate, a bracket and a transmission mechanism, wherein the lower end face of the valve cover is fixedly sealed and connected with the upper end face of the middle cavity of the valve body, and the upper end face is fixedly sealed and connected with the lower end face of the bracket, sealing surfaces cooperating with the valve seat are arranged on both sides of the gate, and the upper end is connected with the lower end of the valve stem, and the upper end of the valve stem passes through the valve cover and is connected with the transmission mechanism on the bracket, a packing sealing device is arranged between the valve stem and the bracket, and a bellows sealing device is arranged between the valve stem and the valve cover, the bellows sealing device is composed of a bellows, a sealing gasket and a positioning ring, the upper and lower ends of the bellows are respectively sealed and welded with the sealing gasket and the positioning ring, the outer circumference of the sealing gasket is press-fitted between the upper end face of the valve cover and the lower end face of the bracket, and the positioning ring is fixedly sealed and installed at the lower end of the valve stem; the bellows sealing device comprises a bellows, a sealing gasket and a positioning ring, the upper and lower ends of the bellows are respectively sealed and welded with the sealing gasket and the positioning ring, the outer circumference of the sealing gasket is sealed and pressed ... The characteristic is that a retractable isolation device is arranged between the sealing gasket and the positioning ring on the outer periphery of the bellows, and the retractable isolation device is composed of an upper isolation sleeve, a middle isolation sleeve and a lower isolation sleeve, the upper end of the upper isolation sleeve is welded and connected to the lower plane of the sealing gasket, and the lower end of the lower isolation sleeve is welded and connected to the outer circular surface of the positioning ring; an outer annular boss is arranged on the upper end of the middle isolation sleeve, which cooperates with the inner limit boss at the lower end of the upper isolation sleeve to form an upper limit mechanism, and the inner ring surface of the inner limit boss at the lower end of the upper isolation sleeve cooperates with the outer circular surface of the middle isolation sleeve to form an upper piston structure; an inner annular boss is arranged on the lower end of the middle isolation sleeve, which cooperates with the outer limit boss at the upper end of the lower isolation sleeve to form a lower limit mechanism, and the inner ring surface of the inner annular boss at the lower end of the middle isolation sleeve cooperates with the outer circular surface of the lower isolation sleeve to form a lower piston structure.

[0006] In the above technical solution, the upper isolation sleeve and the sealing gasket, as well as the lower isolation sleeve and the positioning ring are connected by spot welding.

[0007] In the above technical solution, the sealing surfaces on both sides of the gate plate form a wedge structure, and the sealing surfaces of the inlet and outlet valve seats have a V-shaped structure with the same wedge angle as the sealing surfaces on both sides of the gate plate.

[0008] The beneficial effect of the utility model compared with the prior art is that a retractable isolation sleeve is arranged on the outer periphery of the bellows to seal and isolate the bellows from the medium, preventing medium impurities from adhering to the bellows of the bellows to affect the telescopic performance of the bellows and wear and damage the bellows, thereby improving the reliability of the use of the bellows, achieving zero leakage in the middle cavity, and having the advantages of reliable sealing performance and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a structural schematic diagram of the utility model.

[0010] In the figure: 1 valve body, 2 valve seat, 3 gate, 4 T-buckle, 5 positioning ring, 6 lower isolation sleeve, 7 valve cover, 8 bellows, 9 middle isolation sleeve, 10 upper isolation sleeve, 11 valve stem, 12 sealing gasket, 13 bracket, 14 packing, 15 valve stem nut, 16 handwheel. DETAILED DESCRIPTION

[0011] like Figure 1The zero leakage bellows gate valve shown in the figure comprises a valve body 1, a valve seat 2, a valve cover 7, a valve stem 11, a gate plate 3, a bracket 13 and a transmission mechanism. The lower end face of the valve cover 7 is fixedly sealed and connected to the upper end face of the middle cavity of the valve body 1, and the upper end face is fixedly sealed and connected to the lower end face of the bracket 13. The transmission mechanism adopts a hand wheel 16 to be installed on the upper end of the bracket 13 through a valve stem nut 15. An anti-rotation device is arranged between the bracket 13 and the valve stem 11 to prevent the valve stem 11 from rotating with the hand wheel 16, and the rotation of the hand wheel 16 is converted into an up and down linear movement of the valve stem 11 through the valve stem nut 15. Sealing surfaces that cooperate with the valve seat 2 are arranged on both sides of the gate plate 3, and the upper end is connected to the lower end of the valve stem 11. A T-shaped buckle 4 is arranged at the lower end of the valve stem 11 to cooperate with the T-shaped groove at the upper end of the gate plate 3 to form a T-shaped connecting buckle. The upper end of 11 passes through the valve cover 7 and is connected with the transmission mechanism on the bracket 13. A packing sealing device is arranged between the valve stem 11 and the bracket 13. A bellows sealing device is arranged between the valve stem 11 and the valve cover 7. The packing sealing device is composed of a packing 14 installed in the packing cavity between the bracket 13 and the valve stem 11. The bellows sealing device is composed of a bellows 8, a sealing gasket 12 and a positioning ring 5. The upper and lower ends of the bellows 8 are respectively sealed and welded with the sealing gasket 12 and the positioning ring 5. The outer circumference of the sealing gasket 12 is sealed and pressed between the upper end face of the valve cover 7 and the lower end face of the bracket 13. The positioning ring 5 is fixedly sealed and installed at the lower end of the valve stem 11, isolating the valve stem 11 from the medium in the valve cavity of the valve body 1, realizing zero sealing of the middle cavity, and preventing toxic, harmful, explosive and other dangerous media. The material leaks from the packing sealing device between the valve stem 11 and the bracket 13 to the outside and causes a safety accident; its characteristic is that: a retractable isolation device is arranged between the sealing gasket 12 on the outer periphery of the bellows 8 and the positioning ring 5, and the retractable isolation device is composed of an upper isolation sleeve 10, a middle isolation sleeve 9 and a lower isolation sleeve 6. The upper end of the upper isolation sleeve 10 is welded and connected to the lower plane of the sealing gasket 12. The upper isolation sleeve 10 can also be pressed between the upper end face of the valve cover 7 and the lower plane of the sealing gasket 12 by a radial outer annular convex shoulder seal, and the lower end of the lower isolation sleeve 6 is welded and connected to the outer cylindrical surface of the positioning ring 5; an outer annular convex shoulder is arranged on the upper end of the middle isolation sleeve 9, and the inner limit convex shoulder at the lower end of the upper isolation sleeve 10 cooperates with each other to form an upper limit mechanism to prevent the middle isolation sleeve 9 from detaching from the upper isolation sleeve 10, and the upper isolation sleeve 1 0 The inner ring surface of the inner limit convex shoulder at the lower end cooperates with the outer cylindrical surface of the middle isolation sleeve 9 to form an upper piston structure, and the inner ring surface of the inner limit convex shoulder at the lower end of the upper isolation sleeve 10 and the outer cylindrical surface of the middle isolation sleeve 9 form a piston dynamic sealing structure, which reduces the contact area between the two, reduces the moving friction between the two, and improves the dynamic sealing performance; the inner annular convex shoulder is arranged at the lower end of the middle isolation sleeve 9 and cooperates with the outer limit convex shoulder at the upper end of the lower isolation sleeve 6 to form a lower limit mechanism, and the inner ring surface of the inner annular convex shoulder at the lower end of the middle isolation sleeve 9 and the outer cylindrical surface of the lower isolation sleeve 6 form a lower piston structure. The inner annular convex shoulder at the lower end of the middle isolation sleeve 9 and the outer cylindrical surface of the lower isolation sleeve 6 cooperate with each other to form a piston structure, which reduces the contact area between the two, reduces the moving friction between the two, and improves the dynamic sealing performance.When the valve stem 11 moves up and down, the lower isolation sleeve 6 moves in the middle isolation sleeve 9, and the middle isolation sleeve 9 moves in the upper isolation sleeve 10 in a dynamic seal, isolating the bellows 8 from the middle cavity of the valve body 1, preventing medium impurities from accumulating in the bellows of the bellows 8 to block the expansion and contraction performance of the bellows 8 or wear and damage the bellows 8, thereby ensuring the working reliability of the bellows 8 and improving the zero sealing performance of the middle cavity.

[0012] The upper isolation sleeve 10 and the sealing gasket 12 as well as the lower isolation sleeve 6 and the positioning ring 5 are connected by spot welding to maintain the pressure balance in the cavity between the bellows 8 and the telescopic isolation device, thereby ensuring that the valve stem 11 can move up and down reliably.

[0013] The sealing surfaces on both sides of the gate plate 3 form a wedge structure, and the sealing surfaces of the valve seat 2 in the inlet and outlet channels have a V-shaped structure with the same wedge angle as the sealing surfaces on both sides of the gate plate 3, forming a wedge gate valve structure. The gate plate 3 can also be a flat gate plate.

Claims

1. A zero-leakage bellows gate valve, comprising a valve body (1), a valve seat (2), a valve cover (7), a valve stem (11), a gate plate (3), a bracket (13) and a transmission mechanism, wherein the lower end surface of the valve cover (7) is fixedly sealed and connected to the upper end surface of the middle cavity of the valve body (1), the upper end surface of the valve cover (7) is fixedly sealed and connected to the lower end surface of the bracket (13), the gate plate (3) is provided with sealing surfaces that cooperate with the valve seat (2) on both sides, the upper end of the gate plate (3) is connected to the lower end of the valve stem (11), the upper end of the valve stem (11) passes through the valve cover (7) and is connected to the transmission mechanism on the bracket (13), A packing sealing device is provided between the valve stem (11) and the bracket (13), and a bellows sealing device is provided between the valve stem (11) and the valve cover (7). The bellows sealing device is composed of a bellows (8), a sealing gasket (12) and a positioning ring (5). The upper and lower ends of the bellows (8) are respectively sealed and welded to the sealing gasket (12) and the positioning ring (5). The outer circumference of the sealing gasket (12) is sealed and pressed between the upper end surface of the valve cover (7) and the lower end surface of the bracket (13). The positioning ring (5) is fixedly sealed and installed at the lower end of the valve stem (11). The valve stem (11) is characterized in that: A retractable isolating device is arranged between the sealing gasket (12) and the positioning ring (5) on the outer periphery of the bellows (8), the retractable isolating device comprising an upper isolating sleeve (10), a middle isolating sleeve (9) and a lower isolating sleeve (6), the upper end of the upper isolating sleeve (10) being welded to the lower plane of the sealing gasket (12), and the lower end of the lower isolating sleeve (6) being welded to the outer cylindrical surface of the positioning ring (5); an outer annular shoulder is arranged at the upper end of the middle isolating sleeve (9), and cooperates with an inner limit shoulder at the lower end of the upper isolating sleeve (10) to form an upper limit mechanism, and an inner annular surface of the inner limit shoulder at the lower end of the upper isolating sleeve (10) and dynamically seals with an outer cylindrical surface of the middle isolating sleeve (9) to form an upper piston structure; an inner annular shoulder is arranged at the lower end of the middle isolating sleeve (9), and cooperates with an outer limit shoulder at the upper end of the lower isolating sleeve (6) to form a lower limit mechanism, and an inner annular surface of the inner annular shoulder at the lower end of the middle isolating sleeve (9) and dynamically seals with an outer cylindrical surface of the lower isolating sleeve (6) to form a lower piston structure.

2. The zero leakage bellows gate valve according to claim 1 is characterized in that: The upper isolation sleeve (10) and the sealing gasket (12) as well as the lower isolation sleeve (6) and the positioning ring (5) are connected by spot welding.

3. The zero leakage bellows gate valve according to claim 1 or 2, characterized in that: The sealing surfaces on both sides of the gate plate (3) form a wedge-shaped structure, and the sealing surfaces of the valve seat (2) in the inlet and outlet channels have a V-shaped structure with a wedge angle equal to that of the sealing surfaces on both sides of the gate plate (3).

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