Zero-leakage corrugated pipe stop valve

Abstract

The utility model relates to a zero-leakage corrugated pipe stop valve which comprises a valve body, a valve cover, a valve clack, a valve rod and a transmission mechanism, a corrugated pipe sealing device is arranged between the valve rod and the valve body, the corrugated pipe sealing device is composed of a corrugated pipe, a sealing gasket and a positioning ring, and the upper end and the lower end of the corrugated pipe are respectively connected with the sealing gasket and the positioning ring in a sealing and welding mode. The outer circumference of the sealing gasket is hermetically pressed between the upper end surface of the middle cavity of the valve body and the lower end surface of the valve cover; the device is characterized in that a telescopic isolation device is arranged between a sealing gasket on the periphery of the corrugated pipe and a positioning ring, the telescopic isolation device is of a piston type dynamic sealing structure composed of an upper isolation sleeve and a lower isolation sleeve, and 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.

Description

Technical Field

[0001] The utility model belongs to the field of valves, and in particular relates to a stop valve sealed by a middle cavity bellows. The utility model is suitable for control valves of pipelines of dangerous media such as toxic, harmful, and explosive media. Background Art

[0002] The stop valve is a switch device commonly used in medium conveying pipelines. Its structure consists of a valve body, a valve cover, a valve disc, a valve stem, and a transmission mechanism. A valve seat is arranged on the platform between the inlet and outlet channels of the valve body. The lower end face of the valve disc is provided with a sealing surface that cooperates with the valve seat. The upper end face 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. In order to achieve zero leakage of the valve and prevent toxic, harmful, explosive and other dangerous media from leaking to the outside world and causing safety accidents, a bellows sealing device is arranged between the valve stem and the valve cover to form a bellows stop valve structure to achieve zero leakage in the middle cavity. However, the bellows component of the existing bellows stop 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 telescopic performance, and even causing the bellows to be worn and damaged, 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 zero-leakage bellows stop valve with reliable sealing performance and long service life, which is capable of isolating a bellows from a medium and preventing the bellows from being blocked or worn by impurities in the medium, thereby improving the reliability of the bellows.

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

[0005] A zero-leakage bellows stop valve, comprising a valve body, a valve cover, a valve disc, a valve stem, and a transmission mechanism. A valve seat is arranged on a platform between the inlet and outlet channels of the valve body. The lower end face of the valve disc is provided with a sealing surface that cooperates with the valve seat, and the upper end face 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 bellows sealing device is arranged between the valve stem and the valve body. 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 sealed with the sealing gasket and the positioning ring respectively. Welding connection, the outer circumference seal of the sealing gasket is pressed between the upper end surface of the valve body cavity and the lower end surface of the valve cover, and the positioning ring is fixedly sealed and installed at the lower end of the valve stem; its characteristics are: 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 consists of an upper 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, the lower end of the lower isolation sleeve is welded and connected to the outer circumferential surface of the positioning ring, and the inner circumferential wall of the lower end of the upper isolation sleeve and the outer circumferential surface of the lower isolation sleeve are dynamically sealed.

[0006] In the above technical solution, the lower end of the upper isolation sleeve and the upper end of the lower isolation sleeve are respectively provided with an inner limit boss and an outer limit boss that cooperate with each other, and the inner annular surface of the inner limit boss dynamically seals with the outer cylindrical surface of the lower isolation sleeve.

[0007] 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.

[0008] In the above technical solution, a pressure ring is integrally arranged on the lower end surface of the positioning ring, and the pressure ring has an external thread that cooperates with the internal thread of the center hole on the back side of the valve disc to be connected.

[0009] 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

[0010] Figure 1 It is a structural schematic diagram of the utility model.

[0011] In the figure: 1 valve body, 2 valve seat, 3 valve disc, 4 positioning ring, 5 lower isolation sleeve, 6 upper isolation sleeve, 7 bellows, 8 sealing gasket, 9 valve stem, 10 valve cover, 11 packing, 12 anti-rotation device, 13 bracket, 14 transmission mechanism, 15 valve stem nut. DETAILED DESCRIPTION

[0012] like Figure 1The zero leakage bellows stop valve shown in the figure comprises a valve body 1, a valve cover 10, a valve disc 3, a valve stem 9, and a transmission mechanism 14. A valve seat 2 is arranged on a platform between the inlet and outlet channels of the valve body 1. The valve body 1 adopts a bottom-in and top-out structure, that is, the inlet channel is located at the lower side of the sealing surface of the valve seat 2, and the outlet channel is located at the upper side of the sealing surface of the valve seat 2. The lower end surface of the valve disc 3 is provided with a sealing surface that cooperates with the valve seat 2, and the upper end surface is connected to the lower end of the valve stem 9. The upper end of the valve stem 9 passes through the valve cover 10 and is connected to the transmission mechanism 14 on the bracket 13. The valve stem 9 and the transmission mechanism 14 are connected by a valve stem nut 1 5 transmission connection, the transmission mechanism 14 adopts a hand wheel, which drives the stem nut 15 to rotate together, an anti-rotation device 12 is arranged between the stem 9 and the bracket 13, and the rotation of the stem nut 15 is converted into the up and down movement of the stem 9, a packing sealing device is arranged between the stem 9 and the valve cover 10, and a bellows sealing device is arranged between the stem 9 and the valve body 1. The packing sealing device is composed of a packing 11 installed in a stuffing box between the valve cover 10 and the stem 9, and the bellows sealing device is composed of a bellows 7, a sealing gasket 8 and a positioning ring 4. The bellows 7 moves up and down. The two ends are respectively welded and sealed with a sealing gasket 8 and a positioning ring 4. The outer circumference of the sealing gasket 8 is sealed and pressed between the upper end surface of the middle cavity of the valve body 1 and the lower end surface of the valve cover 10. The positioning ring 4 is fixedly sealed and installed at the lower end of the valve stem 9. The valve stem 9 is sealed and isolated from the middle cavity of the valve body 1 by the bellows 7 to achieve zero leakage of the middle cavity, and prevent toxic, harmful, explosive and other dangerous media from leaking from the valve stem 9 and the valve cover 10 to the outside to cause safety accidents. Its characteristics are: a retractable isolation device is arranged between the sealing gasket 8 and the positioning ring 4 on the outer periphery of the bellows 7, and the retractable isolation device is isolated from the upper The valve stem 9 is composed of a bellows 7 and a lower isolation sleeve 5. The upper end of the upper isolation sleeve 6 is welded to the lower plane of the sealing gasket 8, and the lower end of the lower isolation sleeve 5 is welded to the outer cylindrical surface of the positioning ring 4. The inner cylindrical wall of the lower end of the upper isolation sleeve 6 and the outer cylindrical surface of the lower isolation sleeve 5 are dynamically sealed. When the valve stem 9 moves up and down, the lower isolation sleeve 5 moves dynamically in the upper isolation sleeve 6 to isolate the bellows 7 from the middle cavity of the valve body 1, preventing medium impurities from accumulating in the bellows of the bellows 7 to block the expansion and contraction performance of the bellows 7 or wear and damage the bellows 7, thereby ensuring the working reliability of the bellows 7 and improving the zero sealing performance of the middle cavity.

[0013] The lower end of the upper isolation sleeve 6 and the upper end of the lower isolation sleeve 5 are respectively provided with an inner limit boss and an outer limit boss that cooperate with each other. The inner annular surface of the inner limit boss at the lower end of the upper isolation sleeve 6 is dynamically sealed with the outer cylindrical surface of the lower isolation sleeve 5, and a piston-type dynamic sealing structure is formed between the two, which reduces the sealing contact area between the upper isolation sleeve 6 and the lower isolation sleeve 5 and improves the dynamic sealing matching performance.

[0014] The upper isolation sleeve 6 and the sealing gasket 8 as well as the lower isolation sleeve 5 and the positioning ring 4 are connected by spot welding to maintain the pressure balance in the cavity between the bellows 7 and the telescopic isolation device, thereby ensuring that the valve stem 9 can move up and down reliably.

[0015] A pressure ring is integrally arranged on the lower end surface of the positioning ring 4 , and the pressure ring has an external thread that cooperates with the internal thread of the center hole on the back side of the valve disc 3 to connect the valve stem 9 and the valve disc 3 to each other.

Claims

1. A zero-leakage bellows stop valve, comprising a valve body (1), a valve cover (10), a valve disc (3), a valve stem (9), and a transmission mechanism (14), wherein a valve seat (2) is arranged on a platform between an inlet and an outlet channel of the valve body (1), a lower end surface of the valve disc (3) is provided with a sealing surface that cooperates with the valve seat (2), and an upper end surface is connected to a lower end of a valve stem (9), an upper end of the valve stem (9) passes through the valve cover (10) and is connected to a transmission mechanism (14) on a bracket (13), and a valve seat (2) is arranged on a platform between the inlet and outlet channels of the valve body (1), a sealing surface that cooperates with the valve seat (2) is arranged on a lower end surface of the valve disc (3), and a sealing surface that cooperates with the valve seat (2) is arranged on a lower end surface of the valve disc (3), and a sealing surface that cooperates with the valve seat (2) is arranged on a lower end surface of the valve stem (9), and a sealing surface that cooperates with the valve seat (2) is arranged on a lower end surface of the valve stem (9). A packing sealing device is arranged between the valve stem (9) and the valve body (1), and a bellows sealing device is arranged between the valve stem (9) and the valve body (1), the bellows sealing device comprising a bellows (7), a sealing gasket (8) and a positioning ring (4), the upper and lower ends of the bellows (7) are respectively sealed and welded to the sealing gasket (8) and the positioning ring (4), the outer circumference of the sealing gasket (8) is sealed and pressed between the upper end surface of the middle cavity of the valve body (1) and the lower end surface of the valve cover (10), and the positioning ring (4) is fixedly sealed and installed at the lower end of the valve stem (9); the characteristics are: A retractable isolating device is provided between the sealing gasket (8) and the positioning ring (4) on the outer periphery of the bellows (7), the retractable isolating device comprising an upper isolating sleeve (6) and a lower isolating sleeve (5), the upper end of the upper isolating sleeve (6) being welded to the lower plane of the sealing gasket (8), the lower end of the lower isolating sleeve (5) being welded to the outer cylindrical surface of the positioning ring (4), and the inner cylindrical wall of the lower end of the upper isolating sleeve (6) and the outer cylindrical surface of the lower isolating sleeve (5) being dynamically sealed.

2. The zero leakage bellows stop valve according to claim 1 is characterized in that: The lower end of the upper isolation sleeve (6) and the upper end of the lower isolation sleeve (5) are respectively provided with an inner limit shoulder and an outer limit shoulder that cooperate with each other, and the inner annular surface of the inner limit shoulder at the lower end of the upper isolation sleeve (6) is dynamically sealed with the outer cylindrical surface of the lower isolation sleeve (5).

3. The zero leakage bellows stop valve according to claim 1 or 2, characterized in that: The upper isolation sleeve (6) and the sealing gasket (8) as well as the lower isolation sleeve (5) and the positioning ring (4) are connected by spot welding.

4. The zero leakage bellows stop valve according to claim 1 or 2, characterized in that: A pressure ring is integrally arranged on the lower end surface of the positioning ring (4), and the pressure ring has an external thread that cooperates with the internal thread of the center hole on the back side of the valve disc (3) to be connected.

5. The zero leakage bellows stop valve according to claim 3 is characterized in that: A pressure ring is integrally arranged on the lower end surface of the positioning ring (4), and the pressure ring has an external thread that cooperates with the internal thread of the center hole on the back side of the valve disc (3) to be connected.

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