Main steam release control valve

Abstract

The technical field of control valves of the present invention specifically discloses a main steam release control valve, including a power mechanism, an adjusting mechanism and a connecting bracket. The adjusting mechanism includes a valve body, a valve seat, a valve core and a valve sleeve are arranged in the valve body, the valve core is in a cylindrical shape with one end closed, the valve sleeve is in a cylindrical shape, and the valve sleeve is sleeved on the outer side of the valve core; the valve seat is fixedly installed in the valve body, and the valve core is slidably connected to the valve seat; the valve core is provided with a valve core closing section, a valve core pressure reduction section and a valve core flow section along the length direction, and the valve sleeve is provided with a valve sleeve pressure reduction section along the length direction, and the lengths of the sections are the same; the valve body is provided with a steam inlet cavity, a steam inlet port and a steam outlet, the unclosed end of the valve core is connected to the steam outlet, the closed end is connected to the power mechanism, the steam inlet port is connected to the steam inlet cavity, and the valve sleeve is arranged in the steam inlet cavity; the present invention can achieve different pressure reduction effects according to needs by changing the relative positions of the valve core and the valve sleeve pressure reduction section.

Description

Technical Field

[0001] The invention relates to the technical field of control valves, in particular to a main steam release control valve. Background Art

[0002] In the reactor control system, after the turbine load suddenly decreases significantly, the steam needs to be discharged directly to the condenser, thereby maintaining an artificial load on the steam generator to reduce the transient changes of the reactor coolant system. In the steam discharge system, the main steam release control valve is one of the important devices.

[0003] The existing main steam release control valve structure is similar to the commonly used steam regulating valve structure. Both use the actuator to drive the valve core to move and adjust the valve opening to regulate the steam. However, when applied to the nuclear power field, the steam emission system has high requirements for the pressure difference adjustment capability and full-open flow rate of the control valve. There are multi-stage pressure difference adjustment control valves in the existing technology, but the pressure difference adjustment levels of this type of control valve are fixed and cannot be adjusted according to demand. Under operating conditions where the pressure difference does not need to be adjusted, the multi-stage adjustment will affect the full-open flow rate of the control valve. Therefore, the function of multi-stage pressure difference adjustment limits the performance parameters of the control valve. Summary of the invention

[0004] The purpose of the present invention is to provide a main steam release control valve to solve the following technical problems:

[0005] How to adjust the pressure difference adjustment level of the control valve to meet the needs of different working conditions.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The main steam release control valve comprises a power mechanism, an adjustment mechanism and a connecting bracket, wherein the adjustment mechanism comprises a valve body, wherein a valve seat, a valve core and a valve sleeve are arranged in the valve body, wherein the valve core is in a cylindrical shape with one end closed, and the valve sleeve is in a cylindrical shape, and the valve sleeve is sleeved on the outer side of the valve core;

[0008] The valve seat is fixedly installed in the valve body, and the valve core is slidably connected to the valve seat;

[0009] The valve core is provided with a valve core closing section, a valve core pressure reducing section and a valve core flow section along the length direction, and the valve sleeve is provided with a valve sleeve pressure reducing section along the length direction, and the lengths of the sections are the same;

[0010] The valve body is provided with a steam inlet cavity, a steam inlet port and a steam outlet. The unclosed end of the valve core is connected to the steam outlet, and the closed end is connected to the power mechanism. The steam inlet port is connected to the steam inlet cavity, and the valve sleeve is arranged in the steam inlet cavity.

[0011] In one embodiment, the closing section of the valve core is in close contact with the valve sleeve, and there is a gap between the pressure-reducing section of the valve core and the flow section of the valve core and the valve sleeve;

[0012] The valve core pressure reducing section and the valve sleeve pressure reducing section are provided with throttling holes, and the valve core flow section is provided with perforations;

[0013] The throttle holes are unevenly distributed in the circumferential direction of the valve core and the valve sleeve, and the distribution density is the highest on the side close to the steam inlet.

[0014] In one embodiment, the closed end of the valve core is also connected to a spring;

[0015] The valve core is always subjected to the tension of the spring.

[0016] In one embodiment, the valve sleeve is further provided with a valve sleeve flow section along the length direction;

[0017] The valve sleeve is slidably installed in the valve body, and when the pressure-reducing section of the valve sleeve is entirely located in the steam inlet chamber, the flow section of the valve sleeve is entirely not located in the steam inlet chamber;

[0018] The valve sleeve moves under the action of a driving force.

[0019] In one embodiment, the valve sleeve is further provided with a valve sleeve closing section along the length direction;

[0020] When the valve sleeve closing section is entirely located in the steam inlet chamber, the valve sleeve pressure reducing section and the valve sleeve flow section are not entirely located in the steam inlet chamber.

[0021] In one embodiment, when the control valve is opened with the valve sleeve closing section completely located in the steam inlet chamber, the position of the valve core is adjusted first, and then the position of the valve sleeve is adjusted.

[0022] In one embodiment, at least three connecting rods are connected to one end of the valve sleeve close to the valve core, and the connecting rods are evenly distributed and penetrate the valve body;

[0023] The other side of the connecting rod is connected to an annular connecting piece, and at least three driving and telescopic devices are connected to the annular connecting piece. The driving and telescopic devices are evenly fixed on the connecting bracket and move synchronously.

[0024] In one embodiment, the driving and retracting device is connected to a sub-controller 1, and the sub-controller 1 is used to control the action of the driving and retracting device;

[0025] The power mechanism is connected to a second sub-controller, and the second sub-controller is used to control the action of the power mechanism;

[0026] The sub-controller 1 and the sub-controller 2 are connected to a main controller, and the sub-controller 1 and the sub-controller 2 are controlled by the main controller.

[0027] In one embodiment, the connecting bracket is in the shape of a hollow cylinder, and windows are respectively provided on two sides of the connecting bracket.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention provides a valve core closing section, a valve core pressure reducing section and a valve core flow section in the length direction of the valve core. By changing the relative position of the valve core and the valve sleeve pressure reducing section, different pressure reducing effects can be achieved according to needs, and adaptive selection can be made according to specific needs, thereby realizing the adjustment of the pressure difference adjustment level of the control valve to meet the needs of different working conditions.

[0030] (2) According to the steam fluid analysis, the present invention distributes the throttling holes unevenly, thereby improving the force balance of the valve sleeve and the valve core, reducing the wear during the operation of the control valve, and ensuring the stability of the control valve operation.

[0031] (3) The present invention connects a spring to one end of the valve core when it is closed. On the one hand, when the valve core moves downward, the spring can provide a buffering effect for the movement of the valve core, thereby reducing the impact of the valve core on the valve seat when the valve is quickly adjusted. On the other hand, when the valve core moves upward, the spring can assist the opening of the valve, thereby improving the stability of the valve during adjustment.

[0032] (4) The present invention sets a valve sleeve flow section in the length direction of the valve sleeve, sets the valve sleeve slidingly and moves it under the action of a driving force, thereby being able to achieve selective control of zero-stage pressure reduction, first-stage pressure reduction and second-stage pressure reduction. When the control valve is in the state of zero-stage pressure reduction, the full-open flow of the control valve is the largest, which can ensure the maximum flow performance parameters of the control valve.

[0033] (5) The present invention can provide a control valve with a double closing effect by arranging a valve sleeve closing section along the length direction of the valve sleeve. At the same time, when the control valve is opened when the valve sleeve closing section is completely located in the steam inlet chamber, the valve core position is adjusted first and then the valve sleeve position is adjusted. This can improve the seismic performance of the control valve during operation and ensure that the control valve is used in the harsh working conditions of nuclear power.

[0034] (6) The structure of the connecting bracket in the present invention can increase the contact area between the power mechanism and the regulating mechanism, and the arc-shaped contact surface can improve the overall impact resistance of the control valve. Therefore, through the structural setting of the connecting bracket, the seismic resistance of the control valve can be improved. When applied to the field of nuclear power technology, the stability, service life and opening and closing performance of the control valve can be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described below in conjunction with the accompanying drawings.

[0036] Figure 1is a schematic diagram of the structure of a main steam release control valve in one embodiment of the present invention;

[0037] Figure 2 is a schematic diagram of the valve core structure in one embodiment of the present invention;

[0038] Figure 3 is a schematic structural diagram of a main steam release control valve in another embodiment of the present invention;

[0039] Figure 4 is a schematic diagram of the valve sleeve structure in one embodiment of the present invention;

[0040] Figure 5 It is a schematic diagram of the connecting bracket structure in one embodiment of the present invention.

[0041] Figure numerals: 1. power mechanism; 2. regulating mechanism; 21. valve body; 22. valve core; 221. valve core closing section; 222. valve core pressure reducing section; 223. valve core flow section; 23. valve sleeve; 231. valve sleeve pressure reducing section; 232. valve sleeve flow section; 233. valve sleeve closing section; 24. valve seat; 25. steam outlet; 26. steam inlet; 27. steam inlet chamber; 28. spring; 29. ​​telescopic device; 3. connecting bracket. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] See also Figure 1 , Figure 2 As shown, in one embodiment, a main steam release control valve is provided, and the structure of the control valve includes a power mechanism 1, an adjusting mechanism 2 and a connecting bracket 3. The adjusting mechanism 2 is powered by the power mechanism 1. Specifically, the power mechanism 1 can use changes in air pressure to adjust the movement of the valve core 22. By setting an upper air cavity, a lower air cavity and an air film, the position of the air film is changed by controlling the pressure of the upper air cavity and the lower air cavity. The air film is connected to the valve core 22, so it can drive the valve core 22 to move. The power mechanism 1 can also be implemented in a controller and motor drive manner, using a fully closed squirrel cage three-phase / two-phase motor, and adding closed-loop control of the position on the basis of a commonly used logic controller, which can improve the control accuracy.

[0044] The power mechanism 1 is connected to the regulating mechanism 2 by connecting the bracket 3, wherein the regulating mechanism 2 comprises a valve body 21, in which a valve seat 24, a valve core 22 and a valve sleeve 23 are arranged, the valve core 22 is in the shape of a cylinder with one end closed, the valve sleeve 23 is in the shape of a cylinder with two ends through, and the valve sleeve 23 is sleeved on the outside of the valve core 22; the valve seat 24 is fixedly installed in the valve body 21, and the valve core 22 is slidably connected to the valve seat 24; therefore, the control valve can be adjusted by changing the relative position of the valve core 22 and the valve seat 24. The valve core 22 is further provided with a valve core closing section 221, a valve core pressure reducing section 222 and a valve core flow section 223 along the length direction, the valve sleeve 23 is provided with a valve sleeve pressure reducing section 231 along the length direction, and the lengths of the sections are the same, a steam inlet cavity 27, a steam inlet port 26 and a steam outlet port 25 are provided in the valve body 21, an unclosed end of the valve core 22 is connected to the steam outlet port 25, and a closed end is connected to the power mechanism 1, the steam inlet port 26 is connected to the steam inlet cavity 27, and the valve sleeve 23 is provided at the inlet port 26. In the steam chamber 27, therefore, by changing the relative position of the valve core 22 and the valve sleeve pressure reducing section 231, different control effects can be achieved according to needs. Specifically, when the valve core closing section 221 is opposite to the valve sleeve pressure reducing section 231, the control valve is in a fully closed state. When the valve core pressure reducing section 222 is opposite to the valve sleeve pressure reducing section 231, the valve core pressure reducing section 222 and the valve sleeve pressure reducing section 231 simultaneously play a pressure reducing effect. Therefore, the control valve is in a two-stage pressure reducing state. When the valve core flow section 223 is opposite to the valve sleeve pressure reducing section 231, the valve sleeve pressure reducing section 231 plays a pressure reducing effect. Therefore, the control valve is in a one-stage pressure reducing state. Obviously, the adjustable pressure reducing level setting in this embodiment can be adaptively selected according to specific needs. When a higher pressure reducing level is required, two-stage pressure reducing can be used. When a higher pressure reducing level is not required, one-stage pressure reducing can be used to ensure the performance parameters of the control valve, thereby realizing the adjustment of the pressure difference adjustment level of the control valve to meet the needs of different working conditions.

[0045] As an embodiment of the present invention, please refer to the accompanying drawings. Figure 1 , Figure 2As shown, the closing section of the valve core 22 in this embodiment is tightly attached to the valve sleeve 23, and a sealing ring is arranged inside the valve sleeve 23 for sealing. There is a gap between the valve core pressure reduction section 222 and the valve core flow section 223 and the valve sleeve 23. The valve core pressure reduction section 222 and the valve sleeve pressure reduction section 231 are provided with throttling holes, and the valve core flow section 223 is provided with perforations. Therefore, this gap can ensure that the valve core pressure reduction section 222 and the valve sleeve pressure reduction section 231 will not have the problem of throttling holes being blocked. In addition, the throttling holes in this embodiment are unevenly distributed in the circumferential direction, and the distribution density is the largest on the side close to the steam inlet 26. This arrangement can ensure that the centripetal forces on the valve core 22 and the valve sleeve 23 in all directions are relatively balanced. , further explained, in the prior art, the steam inlet chamber 27 of the sleeve-type control valve generally surrounds the valve sleeve 23 to ensure the force balance of the valve sleeve 23 and the valve core 22. However, when the steam enters the steam inlet chamber 27 from the steam inlet 26, its pressure will decrease to a certain extent. Therefore, the direct pressure on the side of the valve sleeve 23 close to the steam inlet 26 will be relatively large. Therefore, according to the steam fluid analysis, this embodiment distributes the throttle holes unevenly, and the distribution density is the largest on the side close to the steam inlet 26, which appropriately reduces the force on it, thereby further improving the force balance of the valve sleeve 23 and the valve core 22, reducing the wear during the operation of the control valve, and ensuring the stability of the control valve operation.

[0046] It should be noted that the throttling hole is relatively small, and the setting of multiple throttling holes can achieve the effect of reducing pressure, while the aperture of the perforation is relatively large, which is equivalent to the effect of steam passing directly through, and therefore has no pressure reducing effect.

[0047] Please refer to the attached picture Figure 3 As shown, as an implementation mode of the present invention, in this embodiment, a spring 28 is further connected to one end of the valve core 22 that is closed. When the valve core 22 is at the uppermost position, the spring 28 is close to an unstretched state. Therefore, the valve core 22 is always subjected to the pulling force of the spring 28 during the downward movement. Through the setting of the spring 28, on the one hand, during the downward movement of the valve core 22, the setting of the spring 28 can provide a buffering effect for the movement of the valve core 22, thereby reducing the impact of the valve core 22 on the valve seat 24 when the valve is quickly adjusted. On the other hand, during the upward movement of the valve core 22, the setting of the spring 28 can assist the opening of the valve. Therefore, through the setting of the spring 28, the stability of the valve during adjustment can be improved.

[0048] Please refer to the attached picture Figure 3 , Figure 4As shown, as an implementation mode of the present invention, the valve sleeve 23 in this embodiment is further provided with a valve sleeve flow section 232 along the length direction; the valve sleeve 23 is slidably installed in the valve body 21 and moves under the action of the driving force, and the valve sleeve flow section 232 is arranged below the valve sleeve pressure reducing section 231. Therefore, when the valve sleeve pressure reducing section 231 is completely located in the steam inlet chamber 27, the valve sleeve flow section 232 completely enters into the valve body 1, that is, the valve sleeve flow section 232 is not located in the steam inlet chamber 27; through the slidable arrangement of the valve sleeve 23 and the arrangement of the valve sleeve flow section 232, this embodiment can realize the selective control of zero-stage pressure reduction, first-stage pressure reduction and second-stage pressure reduction. Specifically, when the valve core pressure reducing section 222 is opposite to the valve sleeve pressure reducing section 231, the control valve is in a state of secondary pressure reducing; when the valve core pressure reducing section 222 is opposite to the valve sleeve flow section 232 or the valve core flow section 223 is opposite to the valve sleeve pressure reducing section 231, the control valve is in a state of primary pressure reducing; when the valve core flow section 223 is opposite to the valve sleeve flow section 232, the control valve is in a state of zero-level pressure reducing. At this time, the full-open flow of the control valve is the largest. Therefore, through the setting of the valve sleeve 23 structure, the different modes of control valve adjustment can be further expanded. Through the selection of zero-level pressure reducing, the maximum flow performance parameters of the control valve can be guaranteed.

[0049] Please refer to the attached picture Figure 3 , Figure 4 As shown, as an implementation mode of the present invention, the valve sleeve 23 in this embodiment is further provided with a valve sleeve closing section 233 along the length direction, and the valve sleeve closing section 233 is located above the valve sleeve pressure reducing section 231. When the valve sleeve closing section 233 is entirely located in the steam inlet chamber 27, the valve sleeve pressure reducing section 231 and the valve sleeve flow section 232 all enter the valve body 1, that is, the valve sleeve pressure reducing section 231 and the valve sleeve flow section 232 are not entirely located in the steam inlet chamber 27. Therefore, the control valve in this embodiment has a double closing effect. Specifically, when the valve sleeve closing section 233 is entirely located in the steam inlet chamber 27, a single closing effect is achieved. When the valve core closing section 221 moves to the working position, a double closing effect is achieved. Therefore, through the valve sleeve closing section 233 and the valve core closing section 221, the closing performance of the control valve can be improved, and the stability of the control valve operation is ensured.

[0050] Furthermore, when the control valve is opened, if the valve core 22 is subjected to a large force, its movement process will produce movement vibration, which is not conducive to use under harsh working conditions. Therefore, in this embodiment, when the control valve is opened when the valve sleeve closing section 233 is completely located in the steam inlet chamber 27, the position of the valve core 22 is adjusted first, and then the position of the valve sleeve 23 is adjusted. Therefore, when the valve core 22 is adjusted, the adjustment of the valve core 22 is not affected by the steam due to the closure of the valve sleeve 23 to the steam, thereby ensuring the stability of the adjustment of the valve core 22. In addition, since the valve sleeve 23 is tightly fitted to the valve body 21, the adjustment process of the valve sleeve 23 is also relatively smooth. Therefore, through the opening method in this embodiment combined with the structure of the control valve, the seismic resistance of the control valve during operation can be improved, and it is suitable for use in harsh working conditions of nuclear power.

[0051] Further, please refer to the attached figure Figure 3 As shown, the present embodiment provides a specific structure of an adjustable valve sleeve 23. Specifically, three connecting rods are connected to the upper end of the valve sleeve 23. The three evenly arranged connecting rods can ensure the position accuracy of the movement of the valve sleeve 23. The three connecting rods extend to the outside of the valve body 21 and are connected to an annular connecting piece. Three evenly arranged driving telescopic devices 29 are connected to the annular connecting piece. The telescopic devices 29 are fixed on the connecting bracket 3. The driving telescopic devices 29 can be implemented by a hydraulic push rod or an electric push rod, but it is necessary to ensure that the three driving telescopic devices 29 can move synchronously. Therefore, through the control of the driving telescopic devices 29, the valve sleeve 23 can be driven to rise and fall smoothly, thereby realizing different adjustment processes to meet the different usage requirements of the control valve.

[0052] As an implementation mode of the present invention, the telescopic device 29 in this embodiment is connected to a sub-controller 1, which can control the movement of the telescopic device 29, and the power mechanism 1 is connected to a sub-controller 2, which can control the movement of the power mechanism 1. The sub-controller 1 and the sub-controller 2 are connected to a main controller, and the sub-controller 1 and the sub-controller 2 are controlled by the main controller. Therefore, this embodiment can independently or collaboratively control the valve sleeve 23 and the valve core 22 through the main controller, the sub-controller 1 and the sub-controller 2. Through the separate control of the sub-controller 1 and the sub-controller 2 by the main controller, the valve sleeve 23 and the valve core 22 have different matching modes. Through the separate control of the sub-controller 1 and the sub-controller 2, under some special working conditions, the valve sleeve 23 or the valve core 22 can be independently adjusted to meet the needs of different application conditions.

[0053] As an embodiment of the present invention, please refer to the accompanying drawings. Figure 1 , Figure 3 , Figure 5As shown, the connecting bracket 3 in this embodiment is in the shape of a hollow cylinder, and windows are respectively provided on both sides of the connecting bracket 3. Compared with the common connecting rod structure of the regulating valve, the structure of the connecting bracket 3 in this embodiment can increase the contact area between the power mechanism 1 and the regulating mechanism 2, and the arc-shaped contact surface can improve the overall impact resistance of the control valve. Therefore, through the structural setting of the connecting bracket 3, the seismic resistance of the control valve can be improved, and when applied to the field of nuclear power technology, the stability, service life and opening and closing performance of the control valve can be guaranteed.

[0054] Working principle of the present invention: The present invention is provided with a valve core closing section 221, a valve core pressure reduction section 222 and a valve core flow section 223 in the length direction of the valve core 22. By changing the relative position of the valve core 22 and the valve sleeve pressure reduction section 231, different pressure reduction effects can be achieved according to needs, and then adaptive selection can be made according to specific needs. When a higher pressure reduction level is required, two-stage pressure reduction can be used. When a higher pressure reduction level is not required, one-stage pressure reduction can be used to ensure the performance parameters of the control valve, thereby realizing the adjustment of the pressure difference adjustment level of the control valve to meet the needs of different working conditions; according to the analysis of steam fluid, the present invention distributes the throttling holes unevenly, and the distribution density is the largest on the side close to the steam inlet 26, so as to appropriately reduce the forces acting on it. , thereby further improving the force balance of the valve sleeve 23 and the valve core 22, reducing the wear during the operation of the control valve, and ensuring the stability of the control valve operation; the present invention connects a spring 28 to the closed end of the valve core 22. On the one hand, during the downward movement of the valve core 22, the setting of the spring 28 can provide a buffering effect for the movement of the valve core 22, thereby reducing the impact of the valve core 22 on the valve seat 24 when the valve is quickly adjusted. On the other hand, during the upward movement of the valve core 22, the setting of the spring 28 can assist the opening of the valve, thereby improving the stability of the valve during adjustment; the present invention sets a valve sleeve flow section 232 in the length direction of the valve sleeve 23, sets the valve sleeve 23 to slide and move under the action of the driving force, thereby improving the stability of the valve during adjustment. And it is possible to realize the selective control of zero-stage pressure reduction, first-stage pressure reduction and second-stage pressure reduction. When the control valve is in the state of zero-stage pressure reduction, the full-open flow of the control valve is the largest, which can ensure the maximum flow performance parameters of the control valve. Through the arrangement of the valve sleeve 23 structure, the different control modes of the control valve regulation can be further expanded. The present invention can make the control valve have a double closing effect by arranging a valve sleeve closing section 233 along the length direction of the valve sleeve 23. When the valve sleeve closing section 233 is completely located in the steam inlet chamber 27, a single closing effect is achieved. When the valve core closing section 221 moves to the working position, a double closing effect is achieved, thereby improving the closing performance of the control valve and ensuring the stability of the control valve operation. When the control valve is opened when the valve is located in the steam inlet chamber 27, the position of the valve core 22 is adjusted first, and then the position of the valve sleeve 23 is adjusted, which can improve the anti-seismic performance of the control valve during operation and ensure that the control valve is used in harsh nuclear power conditions; the present invention can achieve smooth control of the sliding of the valve sleeve 23 through the connection method between the telescopic device 29 and the valve sleeve 23; the present invention controls the telescopic device 29 and the power mechanism 1 through the control method of the main controller to control the sub-controller 1 and the sub-controller 2 respectively, so that the valve sleeve 23 and the valve core 22 have different matching methods. Through the separate control of the sub-controller 1 and the sub-controller 2, under some special working conditions, the valve sleeve 23 or the valve core 22 can be independently adjusted to meet the needs of different application conditions;The structure of the connecting bracket 3 in the present invention can increase the contact area between the power mechanism 1 and the regulating mechanism 2, and the arc-shaped contact surface can improve the overall impact resistance of the control valve. Therefore, the structural setting of the connecting bracket 3 can improve the anti-seismic performance of the control valve, and when applied to the field of nuclear power technology, the stability, service life and opening and closing performance of the control valve can be guaranteed. ;

Claims

1. A main steam release control valve, comprising a power mechanism (1), a regulating mechanism (2) and a connecting bracket (3), wherein the regulating mechanism (2) comprises a valve body (21), wherein a valve seat (24), a valve core (22) and a valve sleeve (23) are arranged in the valve body (21), and wherein: The valve core (22) is in the shape of a cylinder with one end closed, the valve sleeve (23) is in the shape of a cylinder, and the valve sleeve (23) is sleeved on the outside of the valve core (22); The valve seat (24) is fixedly mounted in the valve body (21), and the valve core (22) is slidably connected to the valve seat (24); The valve core (22) is provided with a valve core closing section (221), a valve core pressure reducing section (222) and a valve core flow section (223) along the length direction, and the valve sleeve (23) is provided with a valve sleeve pressure reducing section (231) along the length direction, and the lengths of the sections are the same; The valve body (21) is provided with a steam inlet chamber (27), a steam inlet port (26) and a steam outlet port (25); an unclosed end of the valve core (22) is connected to the steam outlet port (25), and a closed end is connected to the power mechanism (1); the steam inlet port (26) is connected to the steam inlet chamber (27), and the valve sleeve (23) is arranged in the steam inlet chamber (27); The valve sleeve (23) is further provided with a valve sleeve flow section (232) along the length direction; The valve sleeve (23) is slidably mounted in the valve body (21), and when the valve sleeve pressure reducing section (231) is entirely located in the steam inlet chamber (27), the valve sleeve flow section (232) is entirely not located in the steam inlet chamber (27); The valve sleeve (23) moves under the action of a driving force; The valve sleeve (23) is further provided with a valve sleeve closing section (233) along the length direction; When the valve sleeve closing section (233) is completely located in the steam inlet chamber (27), the valve sleeve pressure reduction section (231) and the valve sleeve flow section (232) are not completely located in the steam inlet chamber (27); When the control valve is opened in a state where the valve sleeve closing section (233) is completely located in the steam inlet chamber (27), the position of the valve core (22) is adjusted first, and then the position of the valve sleeve (23) is adjusted.

2. The main steam release control valve according to claim 1, characterized in that: The closing section of the valve core (22) is in close contact with the valve sleeve (23), and a gap exists between the pressure reducing section (222) of the valve core and the flow section (223) of the valve core and the valve sleeve (23); The valve core pressure reducing section (222) and the valve sleeve pressure reducing section (231) are provided with throttling holes, and the valve core flow section (223) is provided with a through hole; The throttle holes are unevenly distributed in the circumferential direction of the valve core (22) and the valve sleeve (23), and the distribution density is the highest on the side close to the steam inlet (26).

3. The main steam release control valve according to claim 1, characterized in that: The closed end of the valve core (22) is also connected to a spring (28); The valve core (22) is always subjected to the tension of the spring (28).

4. The main steam release control valve according to claim 1, characterized in that: At least three connecting rods are connected to one end of the valve sleeve (23) close to the valve core (22), and the connecting rods are evenly distributed and extend to the outside of the valve body (21); The other side of the connecting rod is connected to an annular connecting piece, and at least three driving telescopic devices (29) are connected to the annular connecting piece. The driving telescopic devices (29) are evenly fixed on the connecting bracket (3) and move synchronously.

5. The main steam release control valve according to claim 4, characterized in that: The driving and retracting device (29) is connected to a sub-controller 1, and the sub-controller 1 is used to control the action of the driving and retracting device (29); The power mechanism (1) is connected to a second sub-controller, and the second sub-controller is used to control the action of the power mechanism (1); The sub-controller 1 and the sub-controller 2 are connected to a main controller, and the sub-controller 1 and the sub-controller 2 are controlled by the main controller.

6. The main steam release control valve according to claim 1, characterized in that: The connecting bracket (3) is in the shape of a hollow cylinder, and windows are respectively provided on two sides of the connecting bracket (3).

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