Device for improving front leakage of main steam safety valve

Abstract

The invention belongs to the technical field of nuclear power safety, and particularly relates to a device for improving front leakage of a main steam safety valve, which is characterized in that a pressure detection system and a pressurization system are arranged for cooperative work, and when the real-time pressure of a main steam pipeline is smaller than the set pressure of the safety valve, the pressure detection system is started; the pressurizing system applies thrust to the valve clack of the safety valve through the push rod, the sealing force between the valve clack and the valve seat is increased, namely, the sealing force of the safety valve is increased, so that the front leakage phenomenon is effectively improved, when the real-time pressure of the main steam pipeline is larger than or equal to the set pressure, the push rod retracts and does not pressurize the valve clack any more, and the safety valve can be normally opened for pressure relief. The front leakage phenomenon of the safety valve can be effectively improved without replacing or improving the safety valve or reducing the working pressure of the main steam pipeline, so that the operation stability and reliability of a unit system are improved.

Description

Technical Field

[0001] This application belongs to the field of nuclear power safety technology, and more specifically, relates to a device for improving the pre-leakage of the main steam safety valve. Background Technology

[0002] A safety valve is an overpressure protection device for pipelines or containers in a nuclear power unit. During the up and down cycles of a nuclear power unit, the pressure in the unit system changes. When the unit system is overpressurized, the safety valve withstands pressure up to its set pressure. At this time, the safety valve can open to release the pressure in the system, thereby preventing damage to the equipment due to excessive pressure. When the unit system pressure drops to the safety valve's reseating pressure, the safety valve can close to restore a seal and maintain normal system operation.

[0003] However, in actual operation, when the unit system pressure gradually rises to near but not yet reach the safety valve's set pressure, the safety valve often experiences unstable sealing, leading to partial steam leakage, a phenomenon known as safety valve pre-leakage. Safety valve pre-leakage not only causes unstable fluctuations in system pressure, interfering with the normal operation of the unit, but also leads to media waste, increases operating costs, and long-term pre-leakage can damage the safety valve's sealing surface, potentially causing more serious safety accidents. Summary of the Invention

[0004] The purpose of this application is to provide a device for improving the pre-leakage of the main steam safety valve, which aims to improve the pre-leakage problem of the safety valve in the nuclear power unit and improve the sealing stability of the safety valve.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: An apparatus for improving pre-leakage of a main steam safety valve is provided, comprising: The pressure detection system is installed outside the main steam pipeline where the safety valve is located. The pressure detection system includes a pressure sampling line and a pressure detector. The pressure sampling line is connected to the main steam pipeline, and the pressure detector is installed on the pressure sampling line and is used to detect the real-time pressure of the pressure sampling line. The pressurization system includes a drive unit, a push rod, and a control device. The push rod is used to drive the valve disc of the safety valve along a first direction, which is parallel to the axial direction of the valve stem of the safety valve. The drive unit is driven to drive the push rod to reciprocate linearly along the first direction. The control device is communicatively connected to a pressure detector to control and adjust the action of the drive unit according to the magnitude of the real-time pressure. Specifically, when the real-time pressure of the pressure sampling pipeline is less than the set pressure of the safety valve, the controller controls the drive component to drive the push rod to apply a thrust to the valve disc in the first direction, thereby causing the valve disc to squeeze the sealing surface of the valve seat. When the real-time pressure is greater than or equal to the set pressure, the controller controls the drive component to drive the push rod to retract in the first direction.

[0006] In some embodiments, the driving element is any one of an electric driving element, a pneumatic driving element, or a hydraulic driving element.

[0007] In some embodiments, the pressure detection system includes at least two sets of pressure sampling lines connected in parallel to the main steam pipeline, each pressure sampling line is provided with a pressure detector, and the pressure detection system also includes a logic device, which is electrically connected to the control device, and each pressure detector is electrically connected to the logic device. Specifically, when the real-time pressure of all pressure sampling lines is less than the set pressure, the logic device outputs a signal to the controller to cause the controller to control the drive element to drive the push rod to apply a thrust to the valve disc in the first direction. When the real-time pressure of any pressure sampling line is greater than or equal to the set pressure, the logic device outputs a signal to the controller to cause the controller to control the drive element to drive the push rod to retract in the first direction.

[0008] In some embodiments, the pressurization system is a pneumatic pressurization system, which further includes an air source and an air supply line. The driving component is a pneumatic chamber, the push rod is a pneumatic rod elastically connected to the pneumatic chamber, the air source is connected to the pneumatic chamber through the air supply line, and the control device is a solenoid valve installed on the air supply line and provided with an exhaust port. Specifically, when the real-time pressure of all pressure sampling lines is less than the set pressure, the solenoid valve demagnetizes and connects the air source and the pneumatic chamber to charge the pneumatic chamber, thereby causing the pneumatic rod to push the valve disc along the first direction. When the real-time pressure of any pressure sampling line is greater than or equal to the set pressure, the solenoid valve is energized and disconnects the air source and the pneumatic chamber and connects the pneumatic chamber and the exhaust port to allow the air supply line to exhaust through the exhaust port, thereby causing the pneumatic rod to retract and no longer push the valve disc.

[0009] In some embodiments, the pressure detector is a normally open pressure relay, the closing pressure of the pressure relay is equal to the set pressure, the reset pressure of the pressure relay is equal to the reseating pressure of the safety valve, and the pressure relay, logic device and control device are electrically connected through a control circuit.

[0010] In some embodiments, the logic device is an OR gate.

[0011] In some embodiments, a three-way valve is provided in the air supply line between the controller and the pneumatic chamber. Two ports of the three-way valve are connected to the air supply line, and the other port of the three-way valve is an air vent. When the air source is open, the three-way valve opens the air supply line to connect the air source and the pneumatic chamber. When the air source is closed, the three-way valve opens the pneumatic chamber to the vent, and the pneumatic chamber exhausts air through the vent.

[0012] In some embodiments, the pressurization system further includes a pressure reducing valve and a pressure gauge disposed on the gas supply line, wherein the pressure reducing valve is disposed between the gas source and the control device, and the pressure gauge is disposed between the pressure reducing valve and the control device.

[0013] In some embodiments, the pressurization system further includes an oil separator and a filter disposed on the air supply line, wherein the oil separator is disposed between the air source and the pressure reducing valve, and the filter is disposed between the oil separator and the pressure reducing valve.

[0014] In some embodiments, a shut-off valve is also provided on the pressure sampling line. The shut-off valve is located between the main steam line and the pressure detector and is used to control the opening and closing of the pressure sampling line.

[0015] The beneficial effects of the device for improving the pre-leakage of the main steam safety valve provided in this application are as follows: By setting up a pressure detection system and a pressurization system to work together, when the real-time pressure of the main steam pipeline is less than the set pressure, the pressurization system applies a thrust to the valve disc through a push rod, thereby increasing the sealing force between the valve disc and the valve seat, that is, increasing the sealing force of the safety valve, thus effectively improving the pre-leakage phenomenon. When the real-time pressure of the main steam pipeline is greater than or equal to the set pressure of the safety valve, the pressurization system does not pressurize the valve disc. The setting of the pressurization system will not affect the normal opening and depressurization of the safety valve and the reseating action after depressurization. Thus, by using the aforementioned device in the embodiments of this application, the pre-leakage phenomenon can be effectively improved without replacing or improving the safety valve itself, or reducing the working pressure of the main steam pipeline, thereby improving the operational stability and reliability of the unit system. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the structure of the device for improving pre-leakage of the main steam safety valve provided in the embodiments of this application. Figure 1 ; Figure 2 for Figure 1 The diagram shown illustrates the structure of a device for improving pre-leakage of the main steam safety valve. Figure 2 .

[0018] The following are the labeling elements in the figure: 10. Pressure detection system; 11. Pressure sampling line; 12. Pressure detector; 121. Control loop; 122. Wire; 13. Logic device; 14. Connector; 15. Shut-off valve; 20. Pressurization system; 21. Drive unit; 211. Air source; 213. Air supply line; 214. Three-way valve; 215. Pressure reducing valve; 216. Pressure gauge; 217. Oil separator; 218. Filter; 22. Push rod; 23. Controller; 24. Connector; 25. Bracket; 100. Safety valve; 103. Valve stem; 200. Main steam line. Detailed Implementation

[0019] To make the technical problem to be solved, the technical solution and the beneficial effects of this application clearer, the following is in conjunction with the appendix. Figure 1 and Figure 2 The present application will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

[0020] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0021] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, "multiple sets" means two or more sets, "multiple pieces" means two or more pieces, and "several" means one or more, unless otherwise explicitly specified.

[0023] A safety valve is an overpressure protection device for pipelines or containers in a nuclear power unit. During the up and down cycles of a nuclear power unit, the system pressure changes. When the system pressure exceeds the set pressure, the safety valve opens to release the pressure and prevent damage to equipment caused by excessive pressure. When the system pressure drops to the safety valve's reseating pressure, the safety valve closes to restore a seal and maintain normal system operation. For example, some nuclear power units use disc spring-loaded safety valves. These valves mainly consist of a valve seat, a valve disc, and a disc spring. When the system is operating normally, the valve disc seals against the valve seat under the elastic thrust of the disc spring, and the safety valve is closed. When the system pressure exceeds the set pressure, the valve disc resists the thrust of the disc spring, causing it to disengage from the valve seat and open the valve. The safety valve then opens to release pressure. When the system pressure is released back to the normal operating pressure, the valve disc reseals the valve seat under the thrust of the disc spring, and the safety valve closes.

[0024] However, in actual operation, when the unit system pressure gradually rises to near but not yet to the set pressure of the safety valve, the valve sealing force may decrease as the system pressure increases. At this time, if the valve sealing structure has poor anti-disturbance capability, the safety valve sealing often becomes unstable, leading to partial steam leakage, i.e., the pre-leakage phenomenon of the safety valve. For example, in a certain unit, the set pressure of some safety valves is about (84±1) bar·g. During the hot shutdown of the unit, when the unit circuit pressure rises to 74 bar·g, some safety valves will exhibit abnormal phenomena such as high discharge pipe temperature and steam emission. This is the pre-leakage phenomenon of the safety valve. When the unit circuit pressure drops below 70 bar·g, the abnormal phenomenon disappears.

[0025] In actual production, pre-leakage of safety valves not only causes unstable fluctuations in system pressure, interfering with the normal operation of the unit, but also leads to media waste and increases operating costs. More seriously, long-term pre-leakage may damage the sealing surface of the safety valve (for example, during pre-leakage, the steam medium in the system washes over the valve sealing surface; if impurities are present in the medium, coupled with the narrow width of the sealing surface of this type of safety valve, it may cause cracks and other damage to the sealing surface, leading to internal leakage of the valve), thus triggering more serious safety accidents and posing a huge threat to the safe operation of nuclear power units. Therefore, it is essential to strictly control and monitor it.

[0026] In related technologies, the impact of system pressure on the sealing performance of safety valves can be improved by reducing the system pressure during unit hot shutdown. However, this operation requires large-scale modification of the unit circuit, which is costly and yields relatively small benefits, resulting in extremely low cost-effectiveness in practice. On the other hand, the sealing force between the valve disc and the valve seat can be increased by increasing the preload of the valve, such as increasing the force of the disc spring pushing the valve disc in a disc spring-loaded safety valve. However, this method will cause the set pressure of the safety valve to increase simultaneously, making it impossible for the valve to open and release pressure when the system reaches the set pressure. In other words, the safety valve cannot be used normally, and the system cannot complete the pressure release normally when necessary.

[0027] Based on this, this application provides an apparatus for improving the pre-leakage of the main steam safety valve to solve the above-mentioned problems. Without reducing the system pressure or changing the set pressure of the safety valve in the unit circuit, it increases the sealing force of the safety valve, thereby improving the pre-leakage phenomenon and reducing the risk of internal leakage and damage to the sealing surface of the safety valve.

[0028] Please refer to the following: Figure 1 and Figure 2 The device for improving the pre-leakage of the main steam safety valve provided in this application embodiment is applicable to, but not limited to, improving the pre-leakage phenomenon of the safety valve installed on the main steam pipeline of the unit's main circuit.

[0029] In the embodiments of this application, such as Figure 1 and Figure 2 As shown, the device for improving the pre-leakage of the main steam safety valve includes a pressure detection system 10 and a pressurization system 20. The pressure detection system 10 is installed outside the main steam pipeline 200 where the safety valve 100 is located. The pressure detection system 10 includes a pressure sampling line 11 and a pressure detector 12. The pressure sampling line 11 is connected to the main steam pipeline 200, and the pressure detector 12 is installed on the pressure sampling line 11 and is used to detect the real-time pressure of the pressure sampling line 11. The pressurization system 20 includes a drive element 21, a push rod 22, and a control device 23. The push rod 22 is used to drive the valve disc of the safety valve 100 in a first direction, and the first direction is connected to the valve stem 103 of the safety valve 100. The axes are parallel, and the drive element 21 is driven to drive the push rod 22 to reciprocate linearly along the first direction. The controller 23 is communicatively connected to the pressure detector 12 to control and adjust the action of the drive element 21 according to the magnitude of the real-time pressure. The pressure detector 12 is communicatively connected to the controller 23. When the real-time pressure of the pressure sampling line 11 is less than the set pressure of the safety valve 100, the controller 23 controls the drive element 21 to drive the push rod 22 to apply a thrust to the valve disc along the first direction, so that the valve disc squeezes the sealing surface of the valve seat. When the real-time pressure is greater than or equal to the set pressure, the controller 23 controls the drive element 21 to drive the push rod 22 to retract along the first direction.

[0030] In this embodiment, the pressure sampling line 11 is an auxiliary pipeline component used to obtain pressure signals from the main steam pipeline 200. Its core function is to extract the medium pressure within the main steam pipeline 200 and transmit it to the pressure detector 12, enabling the pressure detector 12 to indirectly measure the real-time pressure of the main steam pipeline 200 and provide operational information for the pressurization system 20. Exemplarily, one end of the pressure sampling line 11 is typically directly connected to the main steam pipeline 200 via welding, flange, or a dedicated interface, while the other end is connected to the pressure detector 12, thus forming a pressure transmission path: main steam pipeline 200 → pressure sampling line 11 → pressure detector 12. The pressure detector 12 can be a pressure relay or a pressure sensor, etc.

[0031] In a specific embodiment, such as Figure 1 and Figure 2 As shown, a valve is usually installed on the pressure sampling line 11. For example, a shut-off valve 15 can be installed on the pressure sampling line 11. The shut-off valve 15 is located between the main steam line 200 and the pressure detector 12 and is used to control the opening and closing of the pressure sampling line 11. When the pressure sampling line 11 needs to take samples, the shut-off valve 15 is opened. When the pressure sampling line 11 does not need to take samples or when the pressure detector 12 needs to be disassembled and maintained, the shut-off valve 15 is closed to disconnect the connection with the main steam line 200, avoid steam leakage, and improve the safety of the system.

[0032] As an example, when the real-time pressure of the main steam pipeline 200 is less than the reseating pressure of the safety valve 100, the shut-off valve 15 is closed, the pressure sampling line 11 does not sample the main steam pipeline 200, and the pressure detection system 10 and the pressurization system 20 are in a closed state (where closed means the entire device is in a closed state). However, when the pressure detection of the main circuit shows that the real-time pressure of the main steam pipeline 200 rises to near the reseating pressure of the safety valve 100, there is a risk of premature leakage of the safety valve 100. At this time, the shut-off valve 15 is opened, and the pressure detection system 10 and the pressurization system 20 are opened.

[0033] In this embodiment, the driving component 21 refers to a power component that provides driving force to drive the push rod 22 to reciprocate linearly along a first direction. Its core function is to convert energy such as electrical energy, pneumatic energy, or hydraulic energy into mechanical energy to drive the push rod 22 to move, and then transmit this mechanical energy to the valve disc of the safety valve 100 through the push rod 22. As an example, the driving component 21 can be any one of an electric driving component, a pneumatic driving component, or a hydraulic driving component. The driving component 21 can be mounted on the outer surface of the safety valve 100 through a support structure such as a bracket 25.

[0034] In the embodiments of this application, such as Figure 1 and Figure 2As shown, the connection between the push rod 22 and the valve disc of the safety valve 100 along the first direction means that the push rod 22 is indirectly connected to the valve disc, thereby indirectly driving the valve disc to move. For example, the push rod 22 is connected to the valve stem, and the valve disc is driven to move through the valve stem. Alternatively, for some safety valves 100 where part of the valve disc structure is exposed on the valve seat, the push rod 22 can be directly connected to the valve disc, thereby directly driving the valve disc to move. As an example, the push rod 22 can be connected to the valve stem using a connecting part 24 such as a sleeve or telescopic rod.

[0035] In this embodiment, a pressure detection system 10 is installed outside the main steam pipeline 200. The pressure detection system 10 includes a pressure sampling pipeline 11 and a pressure detector 12 installed on the pressure sampling pipeline 11. The pressure sampling pipeline 11 is connected to the main steam pipeline 200 to sample the pipeline pressure. The pressure detector 12 is installed on the pressure sampling pipeline 11 and is used to obtain the real-time pressure of the pipeline. At the same time, the device is also equipped with a pressurization system 20. The pressurization system 20 includes a drive component 21, a push rod 22 and a control device 23. The push rod 22 is arranged axially parallel to the valve stem 103 of the safety valve 100. The drive component 21 is drivenly connected to the push rod 22. The control device 23 is communicatively connected to the pressure detector 12. The pressure detector 12 converts the real-time pressure of the pressure sampling pipeline 11 into a communication signal and transmits it to the control device 23. The control device 23 then controls and adjusts the action of the drive component 21 according to the communication signal to drive the push rod 22 to apply a thrust to the valve disc or drive the push rod 22 to retract.

[0036] When the real-time pressure is less than the set pressure of the safety valve 100, the safety valve 100 has not yet reached the opening pressure. As the pressure increases, it may leak prematurely. At this time, the controller 23 controls the drive component 21 to drive the push rod 22 to apply a thrust to the valve disc in the first direction, thereby causing the valve disc to squeeze the sealing surface of the valve seat, increasing the sealing force between the valve disc and the valve seat sealing surface, thus improving the sealing capacity of the safety valve 100 to resist the increased pressure and achieve the purpose of improving premature leakage. When the real-time pressure is greater than or equal to the set pressure, the safety valve 100 needs to open to release pressure. At this time, the controller 23 controls the drive component 21 to drive the push rod 22 to retract in the first direction away from the valve disc, so that the push rod 22 no longer applies a thrust to the valve disc. In this way, the valve disc can open normally under the pressure of the main steam pipeline 200 to release pressure. When the pressure in the main steam pipeline 200 drops to the reseating pressure, the safety valve 100 reseats.

[0037] Understandably, when the real-time pressure is greater than or equal to the set pressure, the retraction of the drive component 21 in the first direction means that the push rod 22 moves away from the valve seat in the first direction, so that the push rod 22 no longer applies a thrust to the valve disc. Furthermore, when the safety valve 100 is normally depressurizing, the push rod 22 will not obstruct the normal movement of the valve disc in the movement path of the valve disc, that is, the push rod 22 will not interfere with the normal opening and depressurization and normal reseating of the safety valve 100.

[0038] For example, taking a safety valve 100 with a set pressure of 84 bar·g and a reseating pressure of 70 bar·g as an example, in actual use, when the real-time pressure of the main steam pipeline 200 is less than 84 bar·g, for example, when the real-time pressure is 74 bar·g, the safety valve 100 may leak forward. The real-time pressure of the pressure sampling line 11 is basically the same as the real-time pressure of the main steam pipeline 200. At this time, the pressure detector 12 detects that the real-time pressure of the main steam pipeline 200 is less than the set pressure of the safety valve 100. The pressure detector 12 transmits this information to the controller 23. The controller 23 controls the action of the adjusting drive 21, so that the drive 21 can provide power to drive the push rod 22 to apply a thrust to the valve disc in the first direction, thereby causing the valve disc to squeeze the sealing surface of the valve seat, increasing the sealing force between the valve disc and the sealing surface of the valve seat, thereby improving the sealing ability of the safety valve 100 and improving the forward leakage of the safety valve 100. When the real-time pressure of the main steam pipeline 200 reaches or exceeds 84 bar·g, the main steam pipeline 200 needs to release pressure by opening the safety valve 100. At this time, the pressure detector 12 detects that the real-time pressure of the main steam pipeline 200 is greater than or equal to the set pressure of the safety valve 100. The pressure detector 12 transmits this information to the controller 23, and the controller 23 then controls the action of the adjusting drive 21, so that the drive 21 provides power to drive the push rod 22 to retract in the first direction away from the valve seat, so that the valve disc is no longer pushed by the push rod 22, and the sealing force between the valve disc and the valve seat is restored to the state when the safety valve 100 is originally in the reseated closed state. In this way, the valve disc can open under the action of the system pressure of the main steam pipeline 200 to release pressure. When the pressure is released until the real-time pressure of the main steam pipeline 200 drops to 70 bar·g, which is the reseating pressure of the safety valve 100, the safety valve 100 reseated.

[0039] In this embodiment, the controller 23 is an actuator that receives the pressure signal from the pressure detector 12 and converts the electrical signal into action (such as switching the pipeline on and off, or starting and stopping power) to adjust or control the action of the drive component 21. As an example, when the drive component 21 is a pneumatic component, the controller 23 can be a solenoid valve or other control valve. The solenoid valve or other control valve changes the action of the pneumatic component by controlling the on / off state of the pipeline supplying air to it. Alternatively, when the drive component 21 is an electric component, it can be a switching element that changes the action of the electric component by controlling the switching of the electric component's conduction circuit.

[0040] The device for improving pre-leakage of the main steam safety valve in this application embodiment uses a pressure detection system 10 and a pressurization system 20 working in concert. When the real-time pressure of the main steam pipeline 200 is less than the set pressure, the pressurization system 20 pressurizes the valve disc via the push rod 22, thereby increasing the sealing force between the valve disc and the valve seat, i.e., increasing the sealing force of the safety valve 100, thus effectively improving the pre-leakage phenomenon. When the real-time pressure of the main steam pipeline 200 is greater than or equal to the set pressure of the safety valve 100, the pressurization system 20 does not pressurize the valve disc. The setting of the pressurization system 20 does not affect the normal opening and depressurization of the safety valve 100 and its reseating action after depressurization. Thus, by using the aforementioned device in this application embodiment, the pre-leakage phenomenon can be effectively improved without replacing or modifying the safety valve 100 itself, or reducing the working pressure of the main steam pipeline 200, thereby improving the operational stability and reliability of the unit system.

[0041] In some embodiments, such as Figure 1 and Figure 2 As shown, the pressure detection system 10 includes at least two sets of pressure sampling lines 11 connected in parallel to the main steam pipeline 200. Each pressure sampling line 11 is equipped with a pressure detector 12. The pressure detection system 10 also includes a logic device 13, which is electrically connected to the control device 23. Each pressure detector 12 is electrically connected to the logic device 13. When the real-time pressure of all pressure sampling lines 11 is less than the set pressure, the logic device 13 outputs a signal to the control device 23 so that the control device 23 controls the drive element 21 to drive the push rod 22 to apply a thrust to the valve disc in the first direction. When the real-time pressure of any pressure sampling line 11 is greater than or equal to the set pressure, the logic device 13 outputs a signal to the control device 23 so that the control device 23 controls the drive element 21 to drive the push rod 22 to retract in the first direction.

[0042] In this embodiment of the application, the pressure detection system 10 includes multiple, i.e., two or more pressure sampling lines 11, which are connected in parallel to the main steam pipeline 200. Each pressure sampling line 11 is equipped with a pressure detector 12. In this way, the multiple pressure sampling lines 11 can be used as backups for each other. Even if one of the pressure sampling lines 11 or its corresponding pressure detector 12 fails, the other pressure sampling lines 11 can still provide accurate pressure signals, thereby helping to improve the reliability of pressure detection and reduce the risk of pressure detection distortion caused by the failure of a single pressure sampling line 11 or pressure detector 12.

[0043] Based on this, the pressure detection system 10 also includes a logic device 13, which is electrically connected to the controller 23 and each pressure detector 12. The logic device 13 receives the real-time pressure signal from the pressure detector 12 and outputs a control signal to the controller 23 according to the acquired pressure signal.

[0044] Specifically, when the real-time pressure of all pressure sampling lines 11 is less than the set pressure, the real-time pressure of the main steam line 200 has not yet reached the set pressure of the safety valve 100. At this time, the safety valve 100 remains seated. However, as the real-time pressure of the main steam line 200 increases, it may leak prematurely before reaching the set pressure. At this time, the push rod 22 needs to apply a thrust to the valve disc to enhance the sealing performance of the safety valve 100. The logic device 13 outputs a signal to the control device 23 so that the control device 23 controls the drive element 21 to apply a thrust to the push rod 22, thereby increasing the sealing force of the safety valve 100. When When the real-time pressure of any one of the multiple pressure sampling lines 11 is greater than or equal to the set pressure, the real-time pressure of the main steam line 200 has reached the system's operating safety limit pressure. It is necessary to release the pressure by opening the safety valve 100. At this time, regardless of whether the real-time pressure of other pressure sampling lines 11 has reached the set pressure, as long as the pressure detector 12 of one pressure sampling line 11 detects overpressure, the logic device 13 will output a signal to the control device 23, causing the drive element 21 to drive the push rod 22 to retract, so as to avoid the safety valve 100 from failing to open normally due to the continuous force of the drive element 21, thus avoiding the risk of system overpressure.

[0045] Thus, by combining a logic device 13 with multiple sets of parallel pressure sampling lines 11 in the pressure detection system 10, and connecting these lines in parallel to the main steam pipeline 200, real-time pressure is drawn from the main steam pipeline 200 and transmitted to their respective pressure detectors 12. Each pressure detector 12 then converts the acquired pressure signal into an electrical signal and transmits it to the logic device 13. The logic device 13 then generates a control signal according to preset logic rules and transmits the control signal to the controller 23. The controller 23 controls the drive unit 21 to perform corresponding actions according to the control signal, thereby ultimately achieving the pushing and pressurizing of the valve disc to improve the pre-leakage of the safety valve 100, or releasing the valve disc to allow the safety valve 100 to open and release pressure normally. By setting multiple pressure sampling lines 11 to work in coordination with the logic device 13, and the control accuracy of the controller 23, the device in this embodiment can effectively improve the pre-leakage phenomenon of the safety valve 100 without affecting the normal opening and pressure release and reseating closure of the safety valve 100.

[0046] In a specific embodiment, such as Figure 1 and Figure 2 As shown, the pressurization system 20 is a pneumatic pressurization system. The pressurization system 20 also includes an air source 211 and an air supply line 213. The driving component 21 is a pneumatic chamber, and the push rod 22 is a pneumatic rod elastically connected to the pneumatic chamber. The air source 211 is connected to the pneumatic chamber through the air supply line 213. The control device 23 is a solenoid valve installed on the air supply line 213 and equipped with an exhaust port. When the real-time pressure of all pressure sampling lines 11 is less than the set pressure, the solenoid valve demagnetizes and connects the air source 211 to the pneumatic chamber. The air source 211 fills the pneumatic chamber with air, thereby causing the pneumatic rod to push against the valve disc in the first direction. When the real-time pressure of any pressure sampling line 11 is greater than or equal to the set pressure, the solenoid valve is energized and disconnects the air source 211 from the pneumatic chamber and connects the pneumatic chamber to the exhaust port of the solenoid valve, so that the air supply line 213 exhausts air through the exhaust port, thereby causing the pneumatic rod to retract and no longer push against the valve disc.

[0047] In this embodiment, the driving component 21 is a pneumatic chamber, and the push rod 22 is a pneumatic rod elastically connected to the pneumatic chamber via an elastic component. The air source 211 provides compressed air to the pneumatic chamber through the air supply pipe 213. The pneumatic chamber converts air pressure energy into mechanical force, thereby driving the elastic component to move and causing the pneumatic rod, i.e., the push rod 22, to move. The elastic component can be a spring or an elastic assembly with a diaphragm, etc.

[0048] Specifically, when the air source 211 fills the pneumatic chamber with air through the air supply line 213, the internal pressure of the pneumatic chamber increases and drives the push rod 22 to apply a thrust to the valve disc. When the air supply path between the air source 211 and the pneumatic chamber is disconnected, the air source 211 stops supplying air to the pneumatic chamber, and the pneumatic chamber exhausts air through the exhaust port of the solenoid valve. The pneumatic chamber depressurizes and drives the push rod 22 to retract, thus ceasing to apply a thrust to the valve disc. In this way, the pneumatic chamber drives the pneumatic rod, i.e., the push rod 22, to move by filling and pressurizing or depressurizing, thereby achieving the action of pushing and pressurizing or retracting.

[0049] Among them, the control device 23 is a solenoid valve installed on the air supply line 213. The solenoid valve receives the signal from the logic device 13 and, according to the signal, opens the air supply passage, that is, opens the air source 211 and the pneumatic chamber, or closes the air supply passage between the air source 211 and the pneumatic chamber, and opens the exhaust port between the pneumatic chamber and the solenoid valve, thereby realizing the inflation and pressurization or exhaust and depressurization of the pneumatic chamber.

[0050] In actual use, when the solenoid valve loses its magnetism, it connects the air source 211 to the pneumatic chamber. When the solenoid valve is energized, it cuts off the air supply path and connects the pneumatic chamber and the solenoid valve's own exhaust port. Specifically, when the real-time pressure P of all pressure sampling lines 11 satisfies "P < set pressure", the logic device 13 outputs a "first signal" to the solenoid valve. The solenoid valve loses its magnetism, and the air source 211 connects to the pneumatic chamber through the air supply line 213. The air source 211 fills the pneumatic chamber with air, and the increased air pressure in the pneumatic chamber drives the pneumatic rod, i.e., the push rod 22, to pressurize the valve disc in the first direction, making the valve disc and the valve seat sealing surface fit tightly together, thereby suppressing steam leakage and improving the pre-leakage phenomenon of the safety valve 100. When the real-time pressure P' of any pressure sampling line 11 satisfies "P' ≥ set pressure", the solenoid valve will automatically close to the valve disc. At this time, logic device 13 outputs a "second signal" to the solenoid valve, the solenoid valve is energized and cuts off the air supply passage between air source 211 and pneumatic chamber, air source 211 stops supplying air to pneumatic chamber, and at the same time opens the exhaust port of the solenoid valve itself to the pneumatic chamber, the compressed air in the pneumatic chamber is quickly discharged through the exhaust port, the pressure in the pneumatic chamber decreases, the pneumatic rod, i.e. push rod 22, loses thrust and retracts, and safety valve 100 opens under the steam pressure of main steam pipeline 200 to release pressure.

[0051] Thus, by using a pneumatic system to pressurize and control the valve disc, compared to a hydraulic system, there is no need for a complex oil circuit, and compared to an electric system, there is no need for a speed reduction mechanism, resulting in lower maintenance costs and higher long-term operational stability.

[0052] In a specific embodiment, such as Figure 1 and Figure 2As shown, the pressure detector 12 is a normally open pressure relay. The closing pressure of the pressure relay is equal to the set pressure, and the reset pressure of the pressure relay is equal to the reseating pressure of the safety valve 100. The pressure relay, logic device 13 and control device 23 are electrically connected through control circuit 121.

[0053] In this embodiment, the pressure detector 12 is a normally open pressure relay. The pressure relay converts the pressure signal into an electrical signal and transmits the signal to the controller 23 through the logic device 13, such as to the solenoid valve. The controller 23 then executes the corresponding control action according to the electrical signal.

[0054] As an example, in actual use: When the real-time pressure of the pressure sampling line 11 is less than the reseating pressure, the pressure sampling line 11 of the pressure detection system 10 is connected to the main steam line 200, and the pressurization system 20 is connected to the safety valve 100. This is the initial state. At this time, the real-time pressure of each pressure sampling line 11 is less than the reseating pressure, and each pressure relay is in the open state. At this time, the gas source 211 is closed, that is, the pressurization system 20 is in the closed state, and the pressurization system 20 does not pressurize the valve disc. After all components are connected and the device is assembled, turn on the air source 211 and the pressurization system 20. At this time, since the pressure relay is in the off state, the control circuit 121 is disconnected, the solenoid valve is demagnetized and opened, and the air supply line 213 connects the air source 211 and the pneumatic chamber. The air source 211 fills the pneumatic chamber with air, and the push rod 22 is subjected to force to apply a thrust to the valve disc, thereby increasing the sealing force between the valve disc and the valve seat sealing surface, so that it can resist higher pressure and improve the pre-leakage phenomenon of the safety valve 100. Subsequently, as the pressure in the main steam pipeline 200 continues to rise, when the real-time pressure of any pressure sampling pipeline 11 rises to a level greater than or equal to the set pressure, the safety valve 100 needs to open to release pressure. At this time, the pressure relay installed on the pressure sampling pipeline 11 closes, the control circuit 121 is activated, and the logic device 13 receives the electrical signal from one of the pressure relays. The solenoid valve is energized and cuts off the gas supply passage between the gas source 211 and the pneumatic chamber. The gas source 211 stops supplying gas to the pneumatic chamber. At the same time, the pneumatic chamber is connected to the exhaust port of the solenoid valve through the gas supply pipeline 213. The pneumatic chamber releases pressure through the exhaust port, the push rod 22 retracts, the valve disc is no longer subjected to thrust, and the safety valve 100 can open normally to release pressure. Furthermore, as the safety valve 100 depressurizes, the pressure in the main steam pipeline 200 decreases. Before the real-time pressure of each pressure sampling pipeline 11 drops to the reseating pressure, each pressure relay is in the closed state, and the gas supply pipeline 213 is also in the closed state. At this time, the push rod 22 still does not apply a thrust to the valve disc. Finally, as the pressure in the main steam pipeline 200 continues to decrease, when the real-time pressure of each pressure sampling line 11 drops to the reseating pressure, the safety valve 100 reseats, each pressure relay resets and disconnects the control circuit again, causing the solenoid valve to demagnetize and reopen to connect the air source 211 and the pneumatic chamber. The air source 211 refills the pneumatic chamber, and the push rod 22 applies a thrust to the valve disc again, thereby increasing the sealing force between the valve disc and the valve seat after the safety valve 100 reseats, in order to improve the possibility of premature leakage when the pressure in the main steam pipeline 200 rises in the future. Since multiple pressure sampling lines 11 are connected in parallel, and the pressure relays on each pressure sampling line 11 are also connected in parallel, the control loop 121 can only be completely disconnected when all pressure relays on each pressure line are in the open state. That is, the real-time pressure of all pressure sampling lines 11 must be less than the reseating pressure. When the control loop 121 needs to be turned on, only the circuit corresponding to one pressure sampling line 11 needs to be turned on, that is, the real-time pressure of any pressure sampling line 11 must be greater than or equal to the set pressure.

[0055] In a specific embodiment, such as Figure 1 and Figure 2 As shown, the logic device 13 is an OR gate. The logic rule of the OR gate is: if any one of the multiple input signals is "true", the output is "true". Thus, when the real-time pressure of any pressure sampling line 11 is greater than or equal to the set pressure, that is, when any pressure relay inputs a "true" signal to the logic device 13, the control circuit 121 can be turned on to ensure that the solenoid valve is energized, cutting off the air supply passage between the air source 211 and the pneumatic chamber, and opening the exhaust port between the pneumatic chamber and the solenoid valve, so that the push rod 22 retracts and the safety valve 100 can open normally to release pressure.

[0056] In some embodiments, such as Figure 1 and Figure 2 As shown, the pressurization system 20 also includes a pressure reducing valve 215 and a pressure gauge 216 located in the gas supply line 213. The pressure reducing valve 215 is located between the gas source 211 and the control device 23, and the pressure gauge 216 is located between the pressure reducing valve 215 and the control device 23.

[0057] In this embodiment, a pressure reducing valve 215 is provided on the air supply line 213 between the air source 211 and the control device 23, such as a solenoid valve. The pressure reducing valve 215 is used to reduce the pressure of the compressed air output from the air source 211, thereby filling the pneumatic chamber with a more stable low-pressure gas, reducing the risk of damage to related components caused by excessive gas pressure impacting the control device 23 and the pneumatic chamber.

[0058] Based on this, a pressure gauge 216 is also installed between the pressure reducing valve 215 and the control device 23. The pressure gauge 216 is used to detect the pressure of the gas in the gas supply line 213 between the pressure reducing valve 215 and the control device 23, so that the operator can intuitively judge whether the pressure reducing valve 215 has reduced the gas output from the gas source 211 to a suitable range.

[0059] In other embodiments, such as Figure 1 and Figure 2 As shown, the pressurization system 20 also includes an oil separator 217 and a filter 218 located in the air supply line 213. The oil separator 217 is located between the air source 211 and the pressure reducing valve 215, and the filter 218 is located between the oil separator 217 and the pressure reducing valve 215.

[0060] In this embodiment, an oil remover 217 and a filter 218 are provided before the pressure reducing valve 215. The oil remover 217 is used to remove oil from the compressed air, and the filter 218 is used to filter solid impurities from the compressed air. This ensures that the gas entering the pressure reducing valve 215 and subsequent components and pneumatic chambers has good cleanliness, reducing the risk of oil, solid impurities, etc. affecting the normal operation of various components, and providing a guarantee for the normal operation of the drive component 21.

[0061] In some embodiments, such as Figure 1 and Figure 2 As shown, a three-way valve 214 is also provided between the air supply line 213 and the control device 23 and the pneumatic chamber. Two ports of the three-way valve 214 are connected to the air supply line 213, and the other port of the three-way valve 214 is an vent. When the air source 211 is in the open state, the three-way valve 214 opens the air supply line 213 to connect the air source 211 and the pneumatic chamber. When the air source 211 is in the closed state, the three-way valve 214 opens the pneumatic chamber to the vent, and the pneumatic chamber exhausts air through the vent.

[0062] In this embodiment, a three-way valve 214 with a vent is provided between the control device 23 (e.g., a solenoid valve) and the drive component 21 (e.g., a pneumatic chamber). When the air source 211 is open, i.e., the pressurization system 20 is normally open, the three-way valve 214 connects to the air supply line 213, allowing gas to flow normally through the air supply line 213. When the air source 211 is closed, i.e., the entire device is closed, the vent of the three-way valve connects to the pneumatic chamber, allowing residual gas in the pneumatic chamber and the air supply line 213 to be discharged through the vent of the three-way valve 214, thereby reducing the adverse effects of residual gas on the next normal operation of the pressurization system 20. In addition, the three-way valve 214 can also be used to vent and depressurize the pneumatic chamber when the solenoid valve fails (at which time the air source 211 is closed), ensuring that the push rod 22 does not obstruct the opening and depressurization of the safety valve 100.

[0063] Please combine them togetherFigure 1 and Figure 2 The following describes the specific use of the device for improving the pre-leakage of the main steam safety valve provided in the above embodiments of this application, taking a safety valve 100 with a set pressure of 84 bar·g and a reseating pressure of 70 bar·g installed on the main steam pipeline 200 as an example, in conjunction with specific embodiments.

[0064] When the pressure detection component of the main circuit shows that the real-time pressure of the main steam pipeline 200 is less than the reseating pressure of the safety valve 100, i.e., less than 70 bar·g, the pneumatic chamber, i.e., the drive component, is installed onto the outer surface of the safety valve 100 via the bracket 25. The pneumatic rod, i.e., the push rod 22, is connected to the pneumatic chamber, and the pneumatic rod is connected to the valve stem 103 of the safety valve 100 along the axial direction via the connector 24. The air source 211, the pneumatic chamber, and the air supply pipeline 213 are connected, and a solenoid valve, i.e., the control device 23, a three-way valve 214, a pressure gauge 216, a pressure reducing valve 215, an oil separator 217, and a filter 218 are installed on the air supply pipeline 213. Valve 214 connects to gas supply line 213, and two pressure sampling lines 11 are connected in parallel to the main steam line 200. Connector 14 is installed at the tail end of the two pressure sampling lines 11 away from the main steam line 200 to connect pressure relay, i.e., pressure detector 12. At the same time, shut-off valve 15 is installed on the two pressure sampling lines 11. The pressure relay and OR gate, i.e. logic device 13, are connected by two parallel wires 122. The OR gate and solenoid valve are then connected by wire 122. The closing action pressure of the pressure relay is set to the set pressure of safety valve 100, i.e., 84 bar·g, and the reset pressure of the pressure relay is set to the reseating pressure of safety valve 100, i.e., 70 bar·g.

[0065] S10. When the pressure detection component of the main circuit shows that the real-time pressure of the main steam pipeline 200 is less than or equal to the reseating pressure of the safety valve 100, which is 70 bar·g, the gas source 211 is turned on, the two shut-off valves 15 are turned on, the pressure sampling line 11 is connected to the main steam pipeline 200 and pressure sampling is performed on the main steam pipeline 200. At this time, the two pressure relays are in the off state, the gas source 211 is turned on, and the pneumatic chamber is filled with air through the gas supply line 213. The air pressure in the pneumatic chamber increases, and the pneumatic rod, i.e. the push rod 22, is pushed by the air pressure to push the valve disc in the first direction to increase the sealing force of the safety valve 100. S20. As the real-time pressure of the main steam pipeline 200 continues to increase, when the real-time pressure of the main steam pipeline 200 increases to 84 bar·g, at least one of the two pressure relays closes. At this time, the circuit between the closed pressure relay and the OR gate is connected, the control circuit 121 is connected, the solenoid valve is energized, the air supply passage between the air source 211 and the pneumatic chamber is cut off, the exhaust port of the pneumatic chamber and the solenoid valve are connected, the air source 211 stops charging the pneumatic chamber, the pneumatic chamber exhausts through the exhaust port, the pneumatic chamber is depressurized, the pneumatic rod, i.e. the push rod 22, retracts and no longer applies a thrust to the valve disc. At this time, the safety valve 100 returns to the normal sealing state, and the safety valve 100 can be opened to release pressure under the pressure of the main steam pipeline 200. S30. When the main steam pipeline 200 is depressurized to the point where the real-time pressure drops to 70 bar·g, which is the reseating pressure of the safety valve 100, the safety valve 100 reseats. At this time, when the real-time pressure of both pressure sampling pipelines 11 is less than or equal to 70 bar·g, both pressure relays are reset and disconnected, thereby causing the control circuit to be disconnected again. The solenoid valve loses its magnetism, and the air source 211 is connected to the pneumatic chamber through the air supply pipeline 213. The air source 211 refills the pneumatic chamber with air, and the air pressure inside the pneumatic chamber increases. The push rod 22 applies a thrust to the valve disc again to continue to increase the sealing force of the safety valve 100. Alternatively, after safety valve 100 reseated and closed, if the pressure in the main steam pipeline 200 drops to 70 bar·g and it is determined that there is no immediate risk of leakage from safety valve 100, and the real-time pressure in pressure sampling pipeline 11 is less than 70 bar·g, then shut-off valve 15 can be closed, the power switches of the pressure relay, OR valve, and solenoid valve can be turned off, gas supply 211 can be shut off, and three-way valve 214 can be used to open the pneumatic chamber and its vent. Residual gas in the pneumatic chamber and gas supply pipeline 213 can be discharged through the vent of three-way valve 214. At this time, the entire device is in standby mode. When the real-time pressure in the main steam pipeline 200 rises again to the point where safety valve 100 may leak, it can be reopened for use.

[0066] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0067] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An apparatus for improving pre-trip of a main steam safety valve, comprising: The application relates to a pressure detection system and a pressurizing system for a safety valve. The pressure detection system is arranged outside a main steam pipeline where the safety valve is located, and comprises pressure sampling pipelines connected with the main steam pipeline and pressure detectors installed on the pressure sampling pipelines and used for detecting real-time pressure of the pressure sampling pipelines. The pressurizing system comprises a driving member, a push rod and a control member, the push rod is used for driving connection with a valve clack of the safety valve in a first direction parallel to the axial direction of a valve rod of the safety valve, the driving member is drivingly connected with the push rod to drive the push rod to make reciprocating linear motion in the first direction, and the control member is in communication connection with the pressure detectors to control the action of the driving member according to the size of the real-time pressure. When the real-time pressure of the pressure sampling pipelines is smaller than the set pressure of the safety valve, the control member controls the driving member to drive the push rod to apply a pushing force to the valve clack in the first direction, so that the valve clack is pressed against a sealing surface of a valve seat; when the real-time pressure is greater than or equal to the set pressure, the control member controls the driving member to drive the push rod to retreat in the first direction.

2. The device for improving the pre-trip of a main steam safety valve of claim 1, wherein, The driving member is any one of an electric driving member, a pneumatic driving member or a hydraulic driving member.

3. The device for improving the pre-steam safety valve leakage of claim 1, wherein, The pressure detection system comprises at least two groups of pressure sampling pipelines connected in parallel with the main steam pipeline, each of the pressure sampling pipelines is provided with one pressure detector, and the pressure detection system further comprises a logic member, the logic member is electrically connected with the control member, and each of the pressure detectors is electrically connected with the logic member. When the real-time pressure of all the pressure sampling pipelines is smaller than the set pressure, the logic member outputs a signal to the control member to control the driving member to drive the push rod to apply a pushing force to the valve clack in the first direction; when the real-time pressure of any one of the pressure sampling pipelines is greater than or equal to the set pressure, the logic member outputs a signal to the control member to control the driving member to drive the push rod to retreat in the first direction.

4. The device for improving pre-valve leakage of a main steam safety valve of claim 3, wherein, The pressurizing system is a pneumatic pressurizing system, the pressurizing system further comprises a gas source and a gas supply pipeline, the driving member is a pneumatic chamber, the push rod is a pneumatic rod elastically connected with the pneumatic chamber, the gas source is connected with the pneumatic chamber through the gas supply pipeline, and the control member is an electromagnetic valve installed on the gas supply pipeline and provided with an exhaust port. When all the real-time pressures of the pressure sampling pipelines are less than the setting pressure, the electromagnetic valve is de-excited to connect the air source and the pneumatic chamber to inflate the pneumatic chamber, so that the pneumatic rod pushes the valve disc in the first direction; when the real-time pressure of any pressure sampling pipeline is greater than or equal to the setting pressure, the electromagnetic valve is excited to disconnect the air source and the pneumatic chamber and connect the pneumatic chamber and the exhaust port to exhaust the air supply pipeline through the exhaust port, so that the pneumatic rod is withdrawn and no longer pushes the valve disc.

5. The device for improving the pre-steam safety valve leakage of claim 3, wherein, The pressure detector is a normally open pressure relay, the closing action pressure of the pressure relay is equal to the setting pressure, and the reset pressure of the pressure relay is equal to the reset pressure of the safety valve; the pressure relay, the logic device and the control device are electrically connected through a control loop.

6. The device for improving pre-valve leakage of a main steam safety valve of claim 5, wherein, The logic device is an OR gate.

7. The device for improving the pre-steam safety valve leakage of claim 4, wherein, A three-way valve is further arranged at a position between the control device and the pneumatic chamber, two interfaces of the three-way valve are connected with the air supply pipeline, and the other interface of the three-way valve is an exhaust port. When the air source is in an open state, the three-way valve connects the air supply pipeline to connect the air source and the pneumatic chamber; when the air source is in a closed state, the three-way valve connects the pneumatic chamber and the exhaust port, and the pneumatic chamber exhausts through the exhaust port.

8. A device for improving pre-valve leakage of a main steam safety valve according to any one of claims 4 to 7, characterized in that, The pressurizing system further comprises a pressure reducing valve and a pressure gauge arranged in the air supply pipeline, the pressure reducing valve is arranged between the air source and the control device, and the pressure gauge is arranged between the pressure reducing valve and the control device.

9. The device for improving pre-valve leakage of a main steam safety valve of claim 8, wherein, The pressurizing system further comprises an oil removing device and a filter arranged in the air supply pipeline, the oil removing device is arranged between the air source and the pressure reducing valve, and the filter is arranged between the oil removing device and the pressure reducing valve.

10. The device for improving the pre-trip of a main steam safety valve according to any one of claims 1 to 7, characterized in that, A stop valve is further arranged on the pressure sampling pipeline, the stop valve is arranged between the main steam pipeline and the pressure detector, and is used to control the opening and closing of the pressure sampling pipeline.

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