CN108374914B - Two-way check valve - Google Patents

Abstract

The present invention relates to a two-way check valve, specifically to a single-flap double-seat sliding two-way check valve with a cut-off function, which is used as a bypass valve of a nuclear island gate valve; it includes a check valve part and an instrument stop valve part, and the two-way check valve is used as a bypass valve for a nuclear island gate valve. The check valve is provided with three connection ends, namely the inlet end, the middle end and the outlet end. The two-way check valve is connected to the instrument stop valve seat at the inlet end and the outlet end respectively through the check valve disc; the two-way check valve When the instrument stop valves at both ends are kept open, the check valve can realize that the middle end is always connected to the end with higher pressure at the inlet end or outlet end of the valve; and by closing the instrument stop valve at either end, the other two ends are forced to remain connected. Connected; it has both the function of a stop valve and a check valve. Especially when used as a bypass valve of a gate valve, it can keep the middle cavity of the gate valve always connected with the higher pressure end of the inlet or outlet of the gate valve, and can prevent the abnormal rise of the middle cavity of the gate valve. The pressure function ensures the safe operation of the valve.

Description

Two-way check valve

Technical field

The present invention relates to a two-way check valve, specifically to a single-disc double-seat sliding two-way check valve with a cut-off function, which is used as a bypass valve for a nuclear island gate valve.

Background technique

Conventional check valves (check valves) usually consist of a valve body, a valve cover, a valve disc, a middle flange bolt, a middle flange nut, etc. It can only prevent the backflow of the medium, but cannot achieve the function of ensuring that the middle cavity of the gate valve is always connected to the end with higher pressure at the inlet end or outlet end of the gate valve when used as a gate valve bypass valve.

Contents of the invention

In order to solve the problems existing in the above-mentioned prior art, the present invention provides a two-way check valve. The valve is a single-flap double-seat sliding type two-way check valve. It adopts a single-flap double-seat check valve and a valve core that can be quickly replaced. The combined structure of the instrument stop valve.

The technical solution adopted by the present invention to solve the technical problem is: a two-way check valve, which includes a check valve part and an instrument stop valve part. The two-way check valve is provided with three connection ends, namely an inlet end, a middle end and an outlet. end, the two-way check valve is connected to the instrument stop valve seat B at the inlet end and the outlet end respectively through check valve disc A; the check valve part includes: valve body, valve cover, valve disc A, valve Seat A, graphite ring, O-ring, valve seat A is set in the valve body, valve cover is set on the valve body, valve disc A is set in the valve seat, and there is an O-ring between the valve cover and the valve body. The valve cover and the valve body are fastened by bolts. There is a graphite ring between the valve seat and the valve body. There is an O-ring on the valve disc A. There are annular grooves on both ends of the valve cover. The annular groove is connected by the graphite ring. The wire plug forms a sealed connection;

In the instrument stop valve part, an instrument stop valve seat B is provided at both ends of the valve body at the center line of the two-way check valve. The lower end of the valve seat B is provided with a valve seat pressure sleeve, and the top end of the valve seat B is provided with a valve seat. Valve Disc B. Valve Disc B is provided with a valve disc guide sleeve. The top of the valve disc guide sleeve is provided with a packing. The packing is provided with a packing press sleeve. The valve stem is in contact with the inner wall of the packing press sleeve. The lower part of the valve stem passes through the valve in turn. Disc guide sleeve, valve disc, valve seat B and valve seat pressure sleeve. There is a packing pressure plate on the upper part of the packing pressure sleeve. There is a disc spring between the packing pressure sleeve and the packing pressure plate. There is a baffle on the valve stem above the packing pressure plate. , there is a bracket above the baffle. The bracket and the baffle are connected through bracket studs. There is a stop pin on the baffle. There is a valve stem nut in the center of the bracket. The handwheel is connected to the valve stem nut; one end can be closed when needed. The instrument stop valve forces the other two ends of the two-way check valve to remain connected to achieve the safety function of the system.

The two instrument stop valves are designed at an angle of 15 degrees relative to the valve center line, which greatly reduces the valve package size and reduces the valve weight.

A slide-type anti-rotation structure is used between the valve stems and brackets of the two instrument stop valves to prevent the valve stems from rotating and improve the sealing reliability at the packing area and the instrument stop valve seat.

The instrument stop valve has a valve cover-less structure, and the valve stem assembly and the valve body are directly sealed by packing;

The valve seat A of the check valve part and the valve seat B of the instrument stop valve are both quick-change valve seat structures sealed by graphite rings, which are easy to disassemble and repair.

The two-way check valve disc A and the guide surface of the valve seat A adopt spherical contact, which reduces the contact area between the valve disc and the valve seat, thereby reducing frictional resistance and ensuring the opening performance of the valve under low pressure difference.

The two-way check valve adopts a soft sealing structure between disc A and valve seat A to ensure its sealing performance and ensure its reliability, applicability and economy.

The two-way check valve can force the connection between any two ends through two instrument stop valves.

The valve cover of the two-way check valve is designed with a leak detection and sewage discharge plug, which can realize the online leak detection and sewage discharge functions of the valve.

Features of the invention:

The two-way check valve can realize that the middle end is always connected to the end with higher pressure at the inlet end or outlet end of the valve when the instrument stop valves at both ends are kept open; and it can be forced to close the instrument stop valve at either end. The other two ends remain connected;

It has both the function of a stop valve and a check valve. Especially when used as a bypass valve of a gate valve, it can keep the middle cavity of the gate valve always connected with the higher pressure end of the inlet or outlet of the gate valve, and can avoid abnormal pressure increase in the middle cavity of the gate valve. function to ensure the safe operation of the valve;

The function that was originally achieved by combining four valves (two check valves and two stop valves) can now be achieved by one two-way check valve, which greatly reduces the manufacturing cost of the valve and reduces the number of valves. The installation space is beautiful and reliable;

A disc spring group is designed between the packing sleeve and the packing pressure plate of the instrument stop valve, which changes the original structure of designing the disc spring group under the pressure plate nut and avoids the occurrence of uneven packing force leakage due to the deviation of the pressure plate nut. Provides guarantee for reliable sealing of the packing.

Working principle: In the normal state, the instrumented stop valves at both ends are open, and the two-way check valve is an automatic valve. The valve disc is pushed open by the medium with higher pressure at the inlet or outlet end, so that the middle end of the valve and the end with higher inlet or outlet pressure Maintain connectivity to achieve its function; if the system needs to force the middle end of the valve to be connected to either end of the inlet or outlet, this can be achieved by forcibly closing the instrument valve at one end of the valve.

The beneficial effects of the present invention are:

The valve adopts an overall forged structure and adopts a valve group integrated design. It has complete functions, compact structure, and uniform wall thickness. During use, the valve has good fatigue resistance and strong deformation resistance; and an instrument is designed at both ends of the check valve. Type stop valve, when necessary, the stop valve at either end can be closed to force the connection between the middle cavity of the valve and either end. Whether it is an instrumented globe valve seat or a single-disc double-seat sliding check valve seat, it adopts a replaceable living seat structure, which is easy to replace and repair; the valve seals are all made of graphite material, with reliable sealing and stable performance; The single-disc double-seat sliding check valve cleverly designs the check valve so that a valve disc has sealing surfaces at both ends, and there is a valve seat at both ends. Under the action of the medium pressure, the valve disc is pushed to which direction side, whichever side is sealed, while the opposite side remains connected to the middle cavity. The disc guide surface of the single-disc double-seat sliding check valve adopts a spherical structure. The contact area between the spherical structure and the valve seat guide surface is small, and the sliding resistance is small, so that the valve can switch at a low pressure difference, and the switch is flexible and smooth. Stuck. The single-disc double-seat sliding check valve adopts a soft sealing structure between the valve disc and the valve seat to ensure its sealing performance and ensure its reliability, applicability and economy.

Description of the drawings

Figure 1 is a schematic structural diagram of the present invention.

Figure 2 is a side view of Figure 1.

Figure 3 Schematic diagram of the check valve part of the two-way check valve.

Figure 4 Schematic diagram of the instrument stop valve part of the two-way check valve.

In the picture, 1. Valve body, 2. Valve cover, 3. O-ring, 4. Valve seat A, 5. Graphite ring A, 6. Valve disc A, 7. O-ring A, 8. Packing, 9. Packing gland, 10. Disc spring, 11. Packing pressure plate, 12. Bracket nut, 13. Bracket bolt, 14. Gasket, 15. Valve stem nut, 16. Flat nut, 17. Handwheel, 18. Nut, 19 , bracket, 20, bracket stud, 21, stop pin, 22, baffle, 23, valve stem, 24, valve disc guide sleeve, 25, valve disc B, 26, valve seat B, 27, graphite ring B, 28 , Valve seat pressure sleeve, 29. Wire plug, 30. Graphite ring C, 31. Stud, 32. Nut.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and examples.

As a bypass valve of the nuclear island gate valve, the two-way check valve is a single-disc double-seat sliding type. Its function is to ensure that the middle cavity of the nuclear island gate valve remains connected to the end with higher inlet or outlet pressure of the valve, and to prevent abnormalities in the middle cavity of the nuclear island gate valve. Pressurization and pressure lock-in accidents occur, thus providing guarantee for the safe operation of nuclear power plants.

As shown in Figure 1, the two-way check valve includes a check valve part and an instrument stop valve part. The two-way check valve is provided with three connection ends, namely the inlet end, the middle end and the outlet end. The two-way check valve The valve is connected to the instrument stop valve seat B26 at the inlet and outlet ends respectively through the check valve disc A6;

The two-way check valve can force the connection between any two ends through two instrument stop valves.

The valve cover 2 of the two-way check valve is designed with a leak detection and sewage discharge plug 29, which can realize the online leak detection and sewage discharge functions of the valve.

As shown in Figure 2, the check valve part includes: valve body 1, valve cover 2, valve disc A6, valve seat A4, graphite ring 5, O-ring 3. The valve seat A4 is arranged in the valve body 1. The valve cover 2 is set on the valve body 1, the valve disc A6 is set in the valve seat 4, an O-ring 3 is provided between the valve cover 2 and the valve body 1, and the valve cover 2 and the valve body 1 are fastened by bolts , a graphite ring 5 is provided between the valve seat A4 and the valve body 1, an O-ring 7 is provided on the valve disc A6, annular grooves are provided at both ends of the valve cover 2, and the annular groove is formed by the graphite ring 30 and the plug 29 Sealed connection;

As shown in Figure 3, in the instrument stop valve part, an instrument stop valve seat B26 is provided at both ends of the valve body 1 on the center line of the two-way check valve, and a valve seat pressure sleeve is provided at the lower end of the valve seat B26. 28. There is a valve disc B25 on the top of the valve seat B26. There is a valve disc guide sleeve 24 on the valve disc B25. There is a packing 8 on the top of the valve disc guide sleeve 24. There is a packing pressure sleeve 28 on the packing 8. The valve stem 23 and the packing The inner wall of the pressure sleeve 28 is in contact, and the lower part of the valve stem 23 passes through the valve disc guide sleeve 24, the valve disc B25, the valve seat B26 and the valve seat pressure sleeve 28 in sequence. The upper part of the packing pressure sleeve 28 is provided with a packing pressure plate 11. The packing pressure sleeve 28 There is a disc spring 10 between the packing pressure plate 11 and the valve stem 23 above the packing pressure plate 11. There is a baffle 22 on the valve stem 23 above the packing pressure plate 11. There is a bracket 19 above the baffle 22. The bracket 19 and the baffle 22 are connected through bracket studs 20. The baffle 22 is provided with a blocking pin 21, the center of the bracket 19 is provided with a valve stem nut 15, and the handwheel 17 is connected to the valve stem nut 15; when necessary, the instrument stop valve at one end can be closed, and the other two sides of the forced two-way check valve can be closed. The terminals remain connected to realize the security function of the system.

The two instrument stop valves are designed at an angle of 15 degrees relative to the valve center line, which greatly reduces the valve package size and reduces the valve weight.

A slide-type anti-rotation structure is used between the two instrument stop valve stems 23 and the bracket 19 to prevent the valve stem from rotating and improve the sealing reliability of the packing and the instrument stop valve seat.

The instrument stop valve is designed with a valve cover-less structure. The valve stem assembly and the valve body 1 are directly sealed by the packing 8. The structure is simple, the sealing is reliable, and the maintenance is convenient and quick. A disc spring group 10 is designed between the packing sleeve 28 and the packing pressure plate 11 of the instrument stop valve, which changes the original structure of designing the disc spring group under the pressure plate nut and avoids uneven packing force leakage due to the deviation of the pressure plate nut. The appearance of the seal provides guarantee for the reliable sealing of the packing.

The two-way check valve is cleverly designed so that the function that could only be achieved by a combination of four valves (two check valves and two stop valves) can now be achieved by one two-way check valve. It greatly reduces the manufacturing cost of the valve and reduces the installation space of the valve, which is both beautiful and reliable.

The check valve seat A4 of the two-way check valve and the instrument stop valve seat B26 are both quick-change valve seat structures sealed by graphite rings, which are easy to disassemble and repair. The two-way check valve disc A6 and the guide surface of the valve seat A4 adopt spherical contact, which reduces the contact area between the valve disc and the valve seat, thereby reducing frictional resistance and ensuring the valve's opening performance under low pressure differences.

Claims (5)

1. The bidirectional check valve is characterized by comprising a check valve part and an instrument stop valve part, wherein the bidirectional check valve is provided with three connecting ends, the three connecting ends are an inlet end, a middle end and an outlet end respectively, the check valve part comprises a valve body, a valve cover, a valve clack A, a valve seat A, a graphite ring and an O-shaped ring, the valve seat A is arranged in the valve body, the valve cover is arranged on the valve body, the valve clack A is arranged in the valve seat A, the O-shaped ring is arranged between the valve cover and the valve body, the valve cover is fastened with the valve body through bolts, the graphite ring is arranged between the valve seat A and the valve body, the valve clack A is provided with the O-shaped ring, annular grooves are formed at two ends of the valve cover, and the annular grooves are in sealing connection with a plug through the graphite ring; the instrument stop valve part comprises two instrument stop valves which are respectively arranged at two sides of a valve body of the center line of the bidirectional check valve, and the two instrument stop valves are respectively used for controlling the on-off of the inlet end and the outlet end; the lower end of a valve seat B of each instrument stop valve is provided with a valve seat pressing sleeve, the top end of the valve seat B is provided with a valve clack B, the valve clack B is provided with a valve clack guide sleeve, the top end of the valve clack guide sleeve is provided with filler, the filler is provided with a filler pressing sleeve, a valve rod is in contact with the inner wall of the filler pressing sleeve, the lower part of the valve rod sequentially passes through the valve clack guide sleeve, the valve clack B, the valve seat B and the valve seat pressing sleeve, the upper part of the filler pressing sleeve is provided with a filler pressing plate, a disc spring is arranged between the filler pressing sleeve and the filler pressing plate, a baffle is arranged on the valve rod above the filler pressing plate, a bracket is arranged above the baffle and connected with the baffle through a bracket stud, a stop pin is arranged on the baffle, a valve rod nut is arranged in the center of the bracket, and a hand wheel is connected with the valve rod nut; the valve clack A is respectively connected with a valve seat B of the instrument stop valve at the inlet end and a valve seat B of the instrument stop valve at the outlet end; the bidirectional check valve can keep the middle end communicated with the inlet end or the end with higher pressure of the outlet end all the time under the state that the instrument stop valve at the inlet end and the instrument stop valve at the outlet end are kept open; when the instrument stop valve at the inlet end is closed, the middle end and the outlet end can be forced to be communicated; when the instrument stop valve of the outlet end is closed, the middle end and the inlet end can be forced to be communicated; the two instrument stop valves are designed at an angle of 15 degrees relative to the center line of the two-way check valve.

2. The bi-directional check valve of claim 1, wherein a sliding rail type anti-rotation structure is adopted between the valve rod and the bracket of the instrument stop valve.

3. The bi-directional check valve of claim 1 wherein said meter shut-off valve is of a capless construction and wherein said valve stem assembly is directly sealed to said valve body by a packing.

4. The bi-directional check valve of claim 1 wherein a soft seal is employed between said valve flap a and valve seat a.

5. The bi-directional check valve of claim 1 wherein said valve cover is configured with leak detection and drain plugs.