Back-pressure-resistant high-precision spring type safety valve

Abstract

The utility model relates to an anti-backpressure high-precision spring safety valve which comprises a valve body, a valve seat, a valve clack, a valve rod, a guide sleeve and a spring pressure setting device, the lower end of the guide sleeve is pressed at an inlet of the valve body through a radial outer step of the valve seat, and a protruding cylinder arranged on the upper portion of the valve seat is concentrically sleeved in a guide cavity of the guide sleeve. The valve clack is sleeved in the guide cavity of the guide sleeve to form a piston type dynamic sealing structure, so that the concentricity of the valve clack and the sealing surface of the valve seat can be kept, and the sealing matching performance of a sealing pair is improved; the upper end of the guide sleeve is in sealing connection with the inner wall of the spring cavity on the upper portion of the valve body, the valve clack and the spring cavity are sealed and isolated from an outlet cavity of the valve body, back pressure of outlet cavity medium pressure on the valve clack is eliminated, and influence of corrosion of media on the spring on setting pressure is avoided. The device has the advantages of high pressure setting precision, reliable sealing performance of a sealing pair and the like.

Description

Technical Field

[0001] The utility model relates to a breathing type safety valve, in particular to a spring type safety valve. Background Art

[0002] Spring-loaded safety valves are widely used as overpressure protection devices in media pipelines or container systems. Their structure is generally composed of a valve body, a valve seat, a valve disc, a valve stem, a valve cover, a guide sleeve and a spring pressure setting device. The valve seat is installed in the valve body inlet cavity, the upper end of the guide sleeve is press-fitted between the valve body and the valve cover, a sealing surface that cooperates with the valve seat is arranged on the lower plane of the valve disc, the valve disc is movably installed in the guide sleeve, and the valve seat outlet is connected to the valve body discharge port. When the system pressure exceeds the spring set pressure, the medium pressure overcomes the spring force, pushes the valve disc to open, and releases pressure to the discharge port to prevent overpressure from damaging the pipeline or container equipment. However, in many special media pipelines and containers, the medium is not allowed to be discharged into the atmosphere when overpressure occurs. Therefore, the discharge port must be connected to the pipeline system through a pipeline, and the medium is recovered when overpressure is discharged. Therefore, there is back pressure on the back of the valve disc, which affects the set pressure value of the safety valve and causes low set pressure accuracy. Moreover, the processing and installation errors of the guide sleeve can easily cause its center line to be eccentric with the center line of the valve seat, resulting in eccentricity of the sealing surface between the valve disc and the valve seat, resulting in inconsistent sealing pressure ratios in the circumferential direction of the sealing pair, and reducing the sealing performance of the sealing pair. Summary of the invention

[0003] The utility model aims to provide a high-precision spring-type safety valve which can eliminate the back pressure on the back of the valve disc, ensure the concentricity of the guide sleeve and the valve seat, set the pressure with high accuracy and reliable sealing performance, and resist back pressure.

[0004] The technical solution to achieve the purpose of this utility model is:

[0005] A high-precision spring-type safety valve that resists back pressure includes a valve body, a valve seat, a valve disc, a valve stem, a guide sleeve and a spring pressure setting device. The valve seat is fixedly and sealedly installed at the inlet of the valve body, and the valve seat outlet is connected to the valve body outlet cavity. The lower end face of the valve disc is provided with a sealing surface that cooperates with the upper end face of the valve seat. The upper end face of the valve disc is connected to the spring pressure setting device through the valve stem. The spring pressure setting device consists of a spring and an adjusting screw sleeve. The spring is installed between the upper and lower spring seats on the valve stem. The adjusting screw sleeve is adjustable through a thread and installed on the upper end of the valve body. The lower end of the adjusting screw sleeve is pressed against the upper end of the valve body. on the upper end surface of the upper spring seat; its characteristics are: a raised cylinder is provided on the upper part of the valve seat, the outer cylindrical surface of the cylinder is sleeved on the inner hole of the guide sleeve, the lower end of the guide sleeve is pressed on the inlet of the valve body by the radial outer step of the valve seat, a discharge hole connected to the outlet cavity is provided on the side wall of the guide sleeve located outside the sealing surface of the valve seat, the valve disc adopts a cylindrical structure, the outer cylindrical surface of which is dynamically sealed with the guide cavity of the guide sleeve, the axial height of the outer cylindrical surface of the valve disc is greater than the distance between the sealing surface of the valve seat and the upper end of the discharge hole, and the upper end of the guide sleeve is sealed and connected with the inner wall of the spring cavity at the upper part of the valve body.

[0006] In the above technical solution, a limiting boss is provided at the upper end of the guide sleeve.

[0007] Compared with the prior art, the present invention has the following beneficial effects: the lower end of the guide sleeve is pressed on the inlet of the valve body by the radial outer step of the valve seat, the upper part of the valve seat is provided with a raised cylinder which is concentrically sleeved in the guide cavity of the guide sleeve, and the valve disc is sleeved in the guide cavity of the guide sleeve to form a piston-type dynamic seal structure, which can maintain the concentricity of the valve disc and the valve seat sealing surface and improve the sealing matching performance of the sealing pair; the upper end of the guide sleeve is sealed and connected with the inner wall of the spring cavity at the upper part of the valve body, and the valve disc and the spring cavity are sealed and isolated from the outlet cavity of the valve body, eliminating the back pressure of the outlet cavity medium pressure on the valve disc, and avoiding the corrosion of the medium on the spring to affect the set pressure. It has the advantages of high set pressure accuracy and reliable sealing performance of the sealing pair. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a structural schematic diagram of the utility model.

[0009] In the figure: 1 valve seat, 2 valve body, 3 guide sleeve, 4 discharge hole, 5 valve disc, 6 spring chamber, 7 spring, 8 valve stem, 9 upper spring seat, 10 adjusting screw sleeve, 11 valve cap, 12 lower spring seat, 13 limiting boss, 14 guide chamber, 15 outlet chamber, 16 inlet chamber. DETAILED DESCRIPTION

[0010] like Figure 1The anti-back pressure high-precision spring-type safety valve shown in the figure comprises a valve body 2, a valve seat 1, a valve disc 5, a valve stem 8, a guide sleeve 3 and a spring pressure setting device. The valve seat 1 is fixedly and sealedly installed at the inlet of the valve body 2. The inlet of the valve seat 1 is communicated with the medium pipeline or the inner cavity of the container to introduce the medium pressure into the inlet cavity 16. The outlet of the valve seat 1 is communicated with the outlet cavity 15 of the valve body 2. The lower end surface of the valve disc 5 is provided with a sealing surface that cooperates with the upper end surface of the valve seat 1. The upper end surface of the valve disc 5 is connected to the spring pressure setting device through the valve stem 8. The spring pressure setting device is composed of a spring 7 and an adjusting screw sleeve 10. The spring 7 is installed at the valve Between the upper spring seat 9 and the lower spring seat 12 on the rod 8, the adjusting screw sleeve 10 is adjustable and installed on the upper end of the valve body 2 through a thread, and its lower end is pressed against the upper end surface of the upper spring seat 9. By adjusting the axial position of the adjusting screw sleeve 10, the compression amount of the spring 7 is adjusted, and the spring set pressure value is set. A valve cap 11 is provided on the valve body 2 at the upper end of the adjusting screw sleeve 10 to isolate and protect the adjusting screw sleeve 10; its characteristic is that: the upper part of the valve seat 1 has a raised cylinder, and the outer cylindrical surface of the cylinder is sleeved in the guide cavity 14 of the guide sleeve 3 to ensure that the guide sleeve 3 is concentrically connected with the valve seat 1, and the lower end of the guide sleeve 3 is connected by the valve seat 1 The radial outer step is pressed on the inlet of the valve body 2, and a relief hole 4 connected to the outlet cavity 15 is provided on the side wall of the guide sleeve 3 located outside the valve seat sealing surface, so that the outlet of the valve seat 1 is connected to the outlet cavity 15 through the relief hole 4. The sealing surface of the valve seat 1 is higher than the lower hole wall of the relief hole 4, so that the medium can pass through the relief hole 4 without obstruction when the valve disc 5 is opened. A plurality of relief holes 4 are arranged in the circumferential direction of the guide sleeve 3; the valve disc 5 adopts a cylindrical structure, and its outer cylindrical surface and the guide cavity 14 of the guide sleeve 3 form a piston-type dynamic sealing structure, so that the valve disc 5 and the valve seat 1 maintain a high degree of concentricity, avoiding the influence of component processing and assembly errors. The concentricity of the two is affected, and the sealing reliability of the sealing pair is improved. The axial height of the outer cylindrical surface of the valve disc 5 is greater than the distance between the sealing surface of the valve seat 1 and the upper end of the discharge hole 4. When the valve disc 5 is closed, its outer cylindrical surface blocks the discharge hole 4, blocking the medium of the outlet cavity 15 from entering the back of the valve disc 5, eliminating the back pressure affecting the accuracy of the set pressure. The upper end of the guide sleeve 3 is sealed and connected with the inner wall of the spring cavity 6 on the upper part of the valve body 2, and the spring cavity 6 is sealed and isolated from the outlet cavity 15, preventing the medium of the outlet cavity 15 from entering the spring cavity 6 and the guide cavity 14, and eliminating the back pressure and the medium from corroding the spring 7 and affecting the set pressure value.

[0011] A limiting boss 13 is provided at the upper end of the guide sleeve 3 to limit the opening height of the valve flap 5 .

Claims

1. A back pressure resistant high precision spring type safety valve, comprising a valve body (2), a valve seat (1), a valve disc (5), a valve stem (8), a guide sleeve (3) and a spring pressure setting device, wherein the valve seat (1) is fixedly and sealingly mounted at the inlet of the valve body (2), the lower end surface of the valve disc (5) is provided with a sealing surface which cooperates with the upper end surface of the valve seat (1), the upper end surface of the valve disc (5) is connected to the spring pressure setting device through the valve stem (8), the spring pressure setting device comprises a spring (7) and an adjusting screw sleeve (10), the spring (7) is mounted between an upper spring seat (9) and a lower spring seat (12) on the valve stem (8), the adjusting screw sleeve (10) is adjustably mounted on the upper end of the valve body (2) through a thread, and the lower end of the adjusting screw sleeve (10) presses against the upper end surface of the upper spring seat (9); the characteristics are: The valve seat (1) has a raised cylinder on its upper portion, the outer cylindrical surface of which is sleeved in the guide cavity (14) of the guide sleeve (3), the lower end of the guide sleeve (3) is press-fitted to the inlet of the valve body (2) by the radial outer step of the valve seat (1), and a discharge hole (4) communicating with the outlet cavity (15) is provided on the side wall of the guide sleeve (3) located outside the sealing surface of the valve seat (1); the valve flap (5) adopts a cylindrical structure, the outer cylindrical surface of which and the guide cavity (14) of the guide sleeve (3) form a piston-type dynamic sealing structure, the axial height of the outer cylindrical surface of the valve flap (5) is greater than the distance between the sealing surface of the valve seat (1) and the upper end of the discharge hole (4), and the upper end of the guide sleeve (3) is sealedly connected to the inner wall of the spring cavity (6) at the upper portion of the valve body (2).

2. The back pressure resistant high precision spring type safety valve according to claim 1 is characterized in that: A limiting boss (13) is provided at the upper end of the guide sleeve (3).

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