An automatic recirculation valve

Abstract

The application relates to an automatic recirculation valve, relates to the field of power station valves, and comprises a main valve and a bypass valve, the main valve comprises a main valve body and a main valve core, the bypass valve comprises a bypass valve body, a bypass valve core, a bypass valve rod and a bypass valve core, the bypass valve further comprises a sensor for monitoring the position of the bypass valve rod and a closing member for closing the bypass valve core, and the bypass valve core is linked with the eccentric rod through the bypass valve rod. The application is provided with the sensor and the closing member, in normal work, the sensor detects the position of the bypass valve rod, when the sensor monitors that the bypass valve rod drives the bypass valve core to be at a minimum opening degree, the sensor externally outputs a signal, the closing member controls the bypass valve core to completely close the bypass valve, and damage of high-pressure fluid to a sealing member of the bypass valve caused by too small opening of the bypass valve can be effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power station valves, in particular to an automatic recirculation valve. BACKGROUND

[0002] The automatic recirculation valve is also called pump protection valve or minimum flow valve, which is used for automatic recirculation of minimum flow of centrifugal pump to prevent damage caused by overheating, noise and vibration of centrifugal pump under low load.

[0003] In the related art, the automatic recirculation valve includes a main valve and a bypass valve, the main valve includes a main valve body, a guide rod coaxially arranged in the main valve body, and a main valve core slidingly arranged along the guide rod, and an elastic member is arranged between the main valve core and the guide rod to drive the main valve core to reset; the bypass valve includes an eccentric rod, a bypass valve core, and a bypass valve body communicating with the main valve body, the eccentric rod is hinged at one end of the bypass valve body close to the main valve body, and the eccentric rod is linked with the main valve core.

[0004] When the main path works normally, the main valve core slides along the guide rod to open, the eccentric rod moves with the main valve core, the eccentric rod drives the bypass valve core to close the bypass valve, and the fluid passes through the main valve body; when the main path stops working, the pressure on both sides of the main valve core in the main valve body tends to be balanced, the main valve core closes the main valve under the action of the elastic member, the main valve core drives the eccentric rod to open the bypass valve, and the fluid is discharged through the bypass valve.

[0005] In actual use, it is found that when working normally, the bypass valve is in a semi-open state, if the opening amount of the bypass valve is small, the fluid will pass through the bypass valve core at a high pressure and flow rate, the high-speed fluid will cut the surface of the bypass valve core and the bypass valve body, and grooves will be formed on the surface of the bypass valve core and the bypass valve body after a long time, resulting in that the bypass valve cannot be tightly closed when the main path works normally, and the fluid leaks from the bypass valve. SUMMARY

[0006] In order to reduce the damage of high-pressure fluid to the sealing element of the bypass valve at a small opening degree, the present application provides an automatic recirculation valve.

[0007] The automatic recirculation valve provided by the present application adopts the following technical scheme:

[0008] An automatic recirculation valve includes a main valve and a bypass valve, the main valve includes a main valve body and a main valve core, the bypass valve includes a bypass valve body, a bypass valve core, a bypass valve rod, and a bypass valve core, the bypass valve further includes a sensor for monitoring the position of the bypass valve core and a closing element for closing the bypass valve core, and the bypass valve core is linked with the eccentric rod through the bypass valve rod.

[0009] By adopting the technical scheme, the sensor and the closing member are arranged, the sensor monitors the position of the bypass valve rod, when the bypass valve rod drives the bypass valve spool to be at a small opening degree, the sensor outputs a signal to the outside, the closing member drives the bypass valve spool to completely close the bypass valve, the damage of high-speed fluid to the sealing member of the bypass valve when the bypass valve outputs small flow can be effectively reduced, and unnecessary flow loss can also be effectively reduced; during the closing process of the main valve, the sensor monitors that the bypass valve rod moves outward, the sensor outputs a signal to the outside, the closing member releases the bypass valve spool, and the bypass valve spool opens the bypass valve together with the bypass valve rod.

[0010] Optionally, the bypass valve rod is coaxially arranged in the bypass valve body, the bypass valve rod penetrates the bypass valve spool coaxially, limit members are fixed on the bypass valve rod and located at two ends of the bypass valve spool, and the bypass valve spool is slidably arranged between the two limit members.

[0011] By adopting the technical scheme, the bypass valve spool is slidably arranged on the bypass valve rod, and the limit members are fixed on the bypass valve rod, the position of the bypass valve spool is limited by the limit members, the bypass valve spool can slide on the bypass valve rod to a small extent, when the bypass valve rod drives the bypass valve spool to close the bypass valve, the limit member on one side of the bypass valve spool abuts against the bypass valve spool, the closing member can push the bypass valve spool to the direction of closing the bypass valve when the bypass valve is about to be closed, and the bypass valve spool completely closes the bypass valve; when the bypass valve rod drives the bypass valve spool to open the bypass valve, the bypass valve rod moves to one side, the limit member on the other side of the bypass valve spool abuts against the bypass valve spool, and the bypass valve spool is driven to open the bypass valve.

[0012] Optionally, the bypass valve further comprises a bypass valve seat fixed on the bypass valve body, the bypass valve seat is located on the side, away from the eccentric rod, of the bypass valve spool, a flow-through hole is formed through the bypass valve spool, a flow-discharge hole is formed through the bypass valve seat, the flow-through hole and the flow-discharge hole are distributed in a staggered manner, and the bypass valve spool closes the flow-discharge hole when the bypass valve spool abuts against the bypass valve seat.

[0013] By adopting the technical scheme, the bypass valve seat is arranged, the flow-discharge hole and the flow-through hole are formed through the bypass valve seat and the bypass valve spool, the flow-discharge hole and the flow-through hole are distributed in a staggered manner, fluid flows into the space between the bypass valve spool and the bypass valve seat through the flow-through hole on the bypass valve spool, and then flows out through the flow-discharge hole, the flow direction of the fluid needs to be changed between the bypass valve spool and the bypass valve seat, the flow speed of the fluid can be reduced, the erosion of high-speed fluid to the sealing surfaces of the bypass valve seat and the bypass valve spool can be reduced, and the service life of the bypass valve is improved; when the bypass valve needs to be closed, the bypass valve spool abuts against the bypass valve seat, and the bypass valve is closed.

[0014] Optionally, the closing member is an electromagnet, and the closing member is located on the side, away from the bypass valve spool, of the bypass valve seat.

[0015] By adopting the technical scheme, the closing member is arranged as an electromagnet, and when the bypass valve core is close to the bypass valve seat, the closing member can directly attract the bypass valve core to the bypass valve seat, so that the structure is simple and the driving is convenient.

[0016] Optionally, a sealing ring protrusion is arranged on the side of the bypass valve seat close to the bypass valve core, and the sealing ring protrusion separates the through-flow hole and the discharge hole.

[0017] By adopting the technical scheme, the sealing ring protrusion is arranged on the side of the bypass valve seat close to the bypass valve core, and the sealing ring protrusion is made of special material, so that the sealing performance and service life of the bypass valve core and the bypass valve seat are effectively improved.

[0018] Optionally, an elastic member is fixed on the side of the bypass valve seat close to the bypass valve core.

[0019] By adopting the technical scheme, the elastic member is arranged on the side of the bypass valve seat close to the bypass valve core, and when the bypass valve core is opened, the closing member releases the bypass valve core, and the elastic member can timely push away the bypass valve core, so that the bypass valve core can timely open to release pressure.

[0020] Optionally, the bypass valve further comprises a guide sleeve, the guide sleeve is fixed on one end of the bypass valve body close to the main valve body, the guide sleeve is located in the main valve body, one end of the bypass valve rod close to the eccentric rod penetrates through the guide sleeve and is in sliding cooperation with the guide sleeve, a flow inlet hole is arranged on the side wall of the guide sleeve and communicates with the main valve body and the bypass valve body, the eccentric rod is hingedly fixed on one end of the guide sleeve close to the main valve body, and a connecting rod is connected between the eccentric rod and the bypass valve rod.

[0021] By adopting the technical scheme, the guide sleeve is arranged to guide the bypass valve rod, so that the closing tightness of the bypass valve core is improved; the flow inlet hole is arranged on the guide sleeve, so that when the main valve body is closed, the fluid in the main valve body can enter the bypass valve through the flow inlet hole to release pressure; and the connecting rod is hingedly connected between the eccentric rod and the bypass valve rod, so that the connecting rod can prevent the bypass valve rod from being stuck during movement.

[0022] Optionally, the limiting member is arranged as a snap spring, a limiting ring groove is arranged on the bypass valve rod at a position corresponding to the limiting member, and the snap spring is clamped and fixed in the limiting ring groove.

[0023] By adopting the technical scheme, the limiting member is arranged as a snap spring, and the snap spring is clamped and fixed in the limiting ring groove to limit the bypass valve core, so that the structure is simple and the installation is convenient.

[0024] Optionally, the sensor is arranged as a travel switch, the bypass valve rod penetrates through the bypass valve seat and is in sliding fit with the bypass valve seat, the sensor is fixed on the bypass valve body, and the contact of the sensor is located at the end of the bypass valve rod away from the main valve body.

[0025] By adopting the above technical scheme, the sensor is arranged as a travel switch, when the main valve is in normal operation, the bypass valve rod slides to the side of the sensor, when the bypass valve core is in a small opening degree, the end of the bypass valve rod triggers the sensor, and the sensor outputs a signal, so that the structure is simple and convenient to monitor.

[0026] Optionally, a sealing groove is formed in the inner wall of the bypass valve seat, and a sealing ring is arranged in the sealing groove.

[0027] By adopting the above technical scheme, the sealing ring is arranged on the inner wall of the bypass valve seat, so that the sealing performance between the bypass valve seat and the bypass valve rod can be effectively improved.

[0028] In summary, the present application has at least one of the following beneficial technical effects:

[0029] 1. By arranging the sensor and the closing member, the position of the bypass valve rod is monitored by the sensor, when the bypass valve core is in a small opening degree, the sensor outputs a signal, the closing member drives the bypass valve core to completely close the bypass valve, so that the damage of the bypass valve seal caused by high-speed fluid in small flow output of the bypass valve can be effectively reduced, unnecessary flow loss can also be effectively reduced, in the process of closing the main valve, the sensor monitors the movement of the bypass valve rod, the sensor outputs a signal, the closing member releases the bypass valve core, and the bypass valve core opens the bypass valve following the bypass valve rod;

[0030] 2. By slidingly arranging the bypass valve core on the bypass valve rod and fixing the limiting member on the bypass valve rod, the position of the bypass valve core is limited by the limiting member, and the bypass valve core can slide on the bypass valve rod by a small amount, when the bypass valve rod drives the bypass valve core to close the bypass valve, the limiting member on one side of the bypass valve core abuts against the bypass valve core, when closing, the closing member pushes the bypass valve core to the direction of closing the bypass valve, so that the bypass valve core completely closes the bypass valve, when the bypass valve rod drives the bypass valve core to open the bypass valve, the bypass valve rod moves to one side, the limiting member on the other side of the bypass valve core abuts against the bypass valve core, and the bypass valve core is driven to open the bypass valve;

[0031] 3. By setting the bypass valve seat, and opening the drainage hole and the flow hole on the bypass valve seat and the bypass valve core, the drainage hole and the flow hole are staggered, after the fluid flows from the flow hole on the bypass valve core into the bypass valve core and the bypass valve seat, and then flows out from the drainage hole, the fluid needs to change the flow direction between the bypass valve core and the bypass valve seat, which can reduce the flow speed of the fluid, reduce the erosion of high-speed fluid to the sealing surface of the bypass valve seat and the bypass valve core, and improve the overall service life. When the bypass valve needs to be closed, the bypass valve core is attached to the bypass valve seat to close the bypass valve.

[0032] 4. By setting the elastic member on the bypass valve seat close to the bypass valve core, when the bypass valve core is opened, the closing member releases the bypass valve core, and the elastic member can timely pop up the bypass valve core, so that the bypass valve core can be opened in time. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is the overall structure schematic diagram of the embodiment of the application;

[0034] Figure 2 is the structure schematic diagram of the bypass valve of the embodiment of the application;

[0035] Figure 3 is Figure 2 is the enlarged view of the A area in FIG. 6.

[0036] Fig. 1 is a main valve; 11 is a main valve body; 12 is a main valve core; 13 is a guide seat; 14 is a compression spring; 2 is a bypass valve; 21 is a bypass valve body; 22 is an eccentric rod; 23 is a bypass valve rod; 231 is a limiting ring groove; 24 is a bypass valve core; 241 is a flow hole; 25 is a guide sleeve; 251 is a fixed ring convex; 252 is an inlet hole; 26 is a connecting rod; 27 is a bypass valve seat; 271 is a mounting hole; 272 is a drainage hole; 273 is a sealing ring convex; 274 is an elastic member; 275 is a sealing groove; 276 is a sealing ring; 28 is a snap spring; 29 is a closing member; 20 is a sensor. DETAILED DESCRIPTION

[0037] The following will be described in detail in combination with the accompanying drawings. Figures 1-3 The application will be further described in detail.

[0038] The embodiment of the application discloses an automatic recirculation valve, which refers to Figure 1, including the main valve 1 and bypass valve 2, the main valve 1 includes main valve body 11, main valve core 12, guide seat 13 and compression spring 14, guide seat 13 is coaxially fixed in the main valve body 11, main valve core 12 is slidably arranged on the guide seat 13, and the compression spring 14 is located between the guide seat 13 and the main valve core 12. Bypass valve 2 includes bypass valve body 21, eccentric rod 22, bypass valve stem 23 and bypass valve core 24, bypass valve stem 23 is coaxially arranged in bypass valve body 21, eccentric rod 22 is hingedly arranged on bypass valve body 21, the end of eccentric rod 22 is slidably inserted on main valve core 12, main valve core 12 drives eccentric rod 22 to rotate, and eccentric rod 22 is linked with bypass valve stem 23.

[0039] When the main valve 1 works normally, the fluid in the main valve body 11 pushes open the main valve core 12, the main valve core 12 drives the eccentric rod 22 to close the bypass valve 2, and the fluid flows from the main valve body 11; when the main valve body 11 stops working, the main valve core 12 resets to close the main valve 1 under the action of the compression spring 14, the main valve core 12 drives the eccentric rod 22 to open the bypass valve 2, and the fluid flows out from the bypass valve 2.

[0040] Referring to Figure 2 And Figure 3 , the bypass valve body 21 is fixed on one side of the main valve body 11 and communicates with the main valve body 11, the bypass valve 2 further includes a guide sleeve 25, a fixed ring protrusion 251 is coaxially and integrally arranged on the outer side wall of the guide sleeve 25, the fixed ring protrusion 251 is clamped and fixed between the bypass valve body 21 and the main valve body 11, and the guide sleeve 25 is located in the main valve body 11; a flow inlet hole 252 communicating the main valve body 11 and the bypass valve body 21 is formed in the side wall of the guide sleeve 25, and the flow inlet hole 252 is respectively provided with a plurality of circumferential directions of the guide sleeve 25. The bypass valve stem 23 coaxially penetrates the guide sleeve 25 and is in sliding fit with the guide sleeve 25, and the eccentric rod 22 is hingedly fixed to one end of the guide sleeve 25 away from the bypass valve body 21; a connecting rod 26 is arranged between the eccentric rod 22 and the bypass valve stem 23, and the two ends of the connecting rod 26 are respectively hingedly fixed to the eccentric rod 22 and the bypass valve stem 23. When the main valve core 12 drives the eccentric rod 22 to rotate, the eccentric rod 22 will pull the bypass valve stem 23 to reciprocate through the connecting rod 26.

[0041] The bypass valve 2 further comprises a bypass valve seat 27 which is a cylindrical block fixed in the middle of the bypass valve body 21 by screwing, and the bypass valve rod 23 penetrates through the bypass valve seat 27 and is in sliding fit with the bypass valve seat 27 at the end away from the eccentric rod 22. The bypass valve core 24 is a cylindrical block, the bypass valve rod 23 penetrates through the bypass valve core 24 and is in sliding fit with the bypass valve core 24, and the bypass valve core 24 is located between the guide sleeve 25 and the bypass valve seat 27. Two limiters are fixed on the bypass valve rod 23 at both ends of the bypass valve core 24 respectively, the limiter is a circlip 28, a limiting ring groove 231 is formed on the bypass valve rod 23 at the position corresponding to the limiter, the circlip 28 is installed in the limiting ring groove 231, and the bypass valve core 24 can slide within a certain range between the two circlips 28. An installation hole 271 is coaxially formed on the bypass valve seat 27 at the side away from the bypass valve core 24, and a closing member 29 is installed in the installation hole 271, the closing member 29 is an electromagnet. A sensor 20 for monitoring the position of the bypass valve rod 23 is installed on the bypass valve body 21 at the end of the bypass valve rod 23 away from the eccentric rod 22, the sensor 20 is a travel switch, the contact of the sensor 20 is located in the bypass valve body 21, and the contact of the sensor 20 is located at the end of the bypass valve rod 23 away from the eccentric rod 22.

[0042] A through-flow hole 241 is formed through the bypass valve core 24, and a plurality of through-flow holes 241 are distributed in the circumferential direction; a drainage hole 272 is formed through the bypass valve seat 27, and a plurality of drainage holes 272 are distributed in the circumferential direction; the diameter of the circle on which the plurality of through-flow holes 241 are located is smaller than the diameter of the circle on which the plurality of drainage holes 272 are located, and the through-flow hole 241 and the drainage hole 272 are not communicated when the bypass valve core 24 is attached to the bypass valve seat 27.

[0043] When the main valve 1 is opened, the circlip 28 on the bypass valve rod 23 at the side close to the eccentric rod 22 drives the bypass valve core 24 to slide towards the bypass valve seat 27, the end of the bypass valve rod 23 abuts on the contact of the sensor 20 when the distance between the bypass valve core 24 and the bypass valve seat 27 is small, the sensor 20 outputs a signal to the outside, the closing member 29 is magnetized to attract the bypass valve core 24 to the bypass valve seat 27, so that the bypass valve 2 is completely closed; when the main valve 1 is closed, the bypass valve rod 23 slides towards the main valve 1 under the drive of the eccentric rod 22, the end of the bypass valve rod 23 is away from the sensor 20, the sensor 20 outputs a signal, the closing member 29 is de-energized and demagnetized, and the circlip 28 on the bypass valve rod 23 at the side close to the bypass valve seat 27 drives the bypass valve core 24 to move towards the main valve 1 along with the bypass valve rod 23, so that the bypass valve 2 is opened.

[0044] The sealing ring 276 is coaxially arranged on one side of the bypass valve seat 27 close to the bypass valve core 24, and the sealing ring 276 blocks the through-flow hole 241 and the discharge hole 272 when the bypass valve core 24 is attached to the sealing ring 276. The elastic member 274 is coaxially arranged on one side of the bypass valve seat 27 close to the bypass valve core 24, and the elastic member 274 is arranged as a compression spring, and the compression height of the elastic member 274 is smaller than the height of the sealing ring 276 protruding from the bypass valve seat 27. When the bypass valve rod 23 slides to the main valve 1, the closing member 29 is de-energized and demagnetized, and the elastic member 274 can push the bypass valve core 24 to the eccentric rod 22, and timely open the bypass valve 2.

[0045] The sealing groove 275 is arranged on the inner wall of the bypass valve seat 27 in the circumferential direction, and the sealing ring 276 is arranged in the sealing groove 275, which can improve the sealing between the bypass valve seat 27 and the bypass valve rod 23, and prevent fluid from leaking between the bypass valve seat 27 and the bypass valve rod 23.

[0046] The implementation principle of the automatic recirculation valve disclosed in the embodiment of the application is as follows: the sensor 20 and the closing member 29 are arranged in the bypass valve 2, when the bypass valve rod 23 drives the bypass valve core 24 to move to the bypass valve seat 27, and the bypass valve 2 is in a small flow opening state, the sensor 20 detects the position of the bypass valve rod 23 and outputs a signal, and the closing member 29 attracts the bypass valve core 24 to the bypass valve seat 27, so that the bypass valve 2 is completely closed, which can effectively prevent the high-speed fluid from damaging the sealing structure of the bypass valve 2 during the small flow opening of the bypass valve 2, and can also reduce the fluid loss from the bypass valve 2 during normal operation, and save energy consumption. The bypass valve core 24 and the bypass valve seat 27 are arranged, the through-flow hole 241 and the discharge hole 272 are arranged on the bypass valve core 24 and the bypass valve seat 27, and the fluid needs to change the flow direction to be discharged from the discharge hole 272 after the fluid enters the bypass valve body 21 from the through-flow hole 241, which can effectively reduce the flow rate of the fluid, and further prevent the fluid from damaging the sealing structure of the bypass valve 2.

[0047] The above are the preferred embodiments of the application, and are not limited to the protection scope of the application, so that: any equivalent changes made according to the structure, shape, principle of the application should be covered in the protection scope of the application.

Claims

1. An automatic recirculation valve comprising a main valve (1) and a bypass valve (2), the main valve (1) comprising a main valve body (11) and a main valve spool (12), the bypass valve (2) comprising a bypass valve body (21), an eccentric shaft (22), a bypass valve stem (23) and a bypass valve spool (24), characterized in that: The bypass valve (2) further comprises a sensor (20) for monitoring the position of the bypass valve stem (23) and a closing member (29) for closing the bypass valve core (24) which is linked with the eccentric rod (22) through the bypass valve stem (23); The bypass valve stem (23) is coaxially arranged in the bypass valve body (21), the bypass valve stem (23) penetrates the bypass valve core (24) coaxially, and the bypass valve stem (23) is fixed with limiters on both ends of the bypass valve core (24), and the bypass valve core (24) is slidably arranged between the two limiters; The bypass valve (2) further comprises a bypass valve seat (27) fixed on the bypass valve body (21), the bypass valve seat (27) is located on the side of the bypass valve core (24) away from the eccentric rod (22), the bypass valve core (24) is provided with a through-flow hole (241) penetratingly arranged thereon, the bypass valve seat (27) is provided with a discharge hole (272) penetratingly arranged thereon, the through-flow hole (241) and the discharge hole (272) are staggered, and when the bypass valve core (24) is attached to the bypass valve seat (27), the bypass valve core (24) closes the discharge hole (272). The closing member (29) is arranged as an electromagnet, and the closing member (29) is located on the side of the bypass valve seat (27) away from the bypass valve core (24). The sensor (20) is arranged as a travel switch, the bypass valve stem (23) penetrates the bypass valve seat (27) and is in sliding fit with the bypass valve seat (27), the sensor (20) is fixed on the bypass valve body (21), and the contact of the sensor (20) is located on the end of the bypass valve stem (23) away from the main valve body (11); by arranging the sensor (20) and the closing member (29) in the bypass valve (2), when the bypass valve stem (23) drives the bypass valve core (24) to move to the side of the bypass valve seat (27) and the bypass valve (2) is in a small-flow opening state during normal operation of the main valve (1), the sensor (20) monitors the position of the bypass valve stem (23) and outputs a signal, and the closing member (29) attracts the bypass valve core (24) to the bypass valve seat (27), so that the bypass valve (2) is completely closed, which can effectively prevent the high-speed fluid from damaging the sealing structure of the bypass valve (2) during the small-flow opening process of the bypass valve (2); meanwhile, the fluid loss from the bypass valve (2) during normal operation can be reduced, and energy consumption can be saved.

2. An automatic recirculation valve according to claim 1, characterized in that: The bypass valve seat (27) is provided with a sealing ring (276) protruding (273) on the side close to the bypass valve core (24), and the sealing ring (276) protruding (273) separates the through-flow hole (241) and the discharge hole (272).

3. An automatic recirculation valve according to claim 2, wherein: The bypass valve seat (27) is fixed with an elastic member (274) on the side close to the bypass valve core (24).

4. An automatic recirculation valve according to claim 1, wherein: The bypass valve (2) further comprises a guide sleeve (25) fixed on one end of the bypass valve body (21) close to the main valve body (11), the guide sleeve (25) is located in the main valve body (11), the bypass valve rod (23) penetrates the guide sleeve (25) and is in sliding fit with the guide sleeve (25) at one end close to the eccentric rod (22), a flow inlet hole (252) is formed on the side wall of the guide sleeve (25) and communicates with the main valve body (11) and the bypass valve body (21), the eccentric rod (22) is hingedly fixed on one end of the guide sleeve (25) close to the main valve body (11), and the eccentric rod (22) and the bypass valve rod (23) are connected by a connecting rod (26).

5. An automatic recirculation valve according to claim 1, wherein: The limiting part is a snap spring (28), a limiting ring groove (231) is formed on the bypass valve rod (23) at a position corresponding to the limiting part, and the snap spring (28) is clamped and fixed in the limiting ring groove (231).

6. An automatic recirculation valve according to claim 1, wherein: A sealing groove (275) is formed on the inner wall of the bypass valve seat (27), and a sealing ring (276) is installed in the sealing groove (275).

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