A redundant regulating actuator for a high-pressure bypass pressure reducing valve

Abstract

This invention discloses a redundant regulating actuator for a high-pressure bypass pressure reducing valve, relating to the field of boiler bypass control technology. The actuator, used to regulate the opening of the pressure reducing valve, includes: a PLC controller, a hydraulic system, a cylinder, and a displacement sensor. The displacement sensor is connected to the valve stem of the pressure reducing valve to detect the valve opening and output a feedback signal. The piston rod of the cylinder is connected to the valve stem of the pressure reducing valve via a coupling. The hydraulic system includes a first hydraulic channel and a second hydraulic channel connected in parallel, as well as a pilot control directional valve. The control terminal of the pilot control directional valve is externally connected to an electromagnetic directional valve. The two hydraulic channels are connected in parallel, and the PLC controller controls the electromagnetic directional valve to switch the hydraulic channels, activating the proportional valve of the backup hydraulic channel and isolating the faulty proportional valve, thereby achieving master-slave switching of the hydraulic channels.

Description

Technical Field

[0001] This invention relates to the field of boiler bypass control technology, and in particular to a redundant regulating actuator for a high-pressure bypass pressure reducing valve. The actuator employs a dual proportional valve redundancy design and a hydraulic actuator that achieves automatic master-slave switching based on closed-loop deviation detection using a displacement sensor. Background Technology

[0002] The high and low pressure bypass control system is a crucial component of the intermediate reheat boiler's thermal system. When the boiler's startup or operating conditions are mismatched with the supporting equipment, the superheater outlet steam, which is not performing work, needs to pass through the high-pressure bypass pressure reducing valve (BP) to enter the reheater inlet. The reheated steam then passes through the low-pressure bypass pressure reducing valve (LBP) to enter the condenser. To prevent reheater overpressure and overheating, and condenser overload, the bypass steam must be desuperheated and depressurized. High-pressure bypass steam desuperheating is achieved using feedwater via a spray isolation valve (BD) and a high-pressure bypass spray desuperheating valve (BPE). Therefore, the high-pressure bypass pressure reducing valve (BP) is a critical piece of equipment in the intermediate reheat boiler. During boiler startup and shutdown due to malfunctions, the boiler's steam-water circulation relies entirely on the high-pressure bypass pressure reducing valve (BP). A failure of the high-pressure bypass pressure reducing valve (BP) will directly affect the normal startup of the boiler or pose a significant safety hazard in the event of a sudden boiler failure requiring emergency shutdown. Therefore, the high-pressure bypass pressure reducing valve (BP) must be kept in normal operating condition at all times.

[0003] In existing technologies, the actuator of a high-pressure bypass pressure reducing valve (BP) typically uses a single proportional valve to achieve continuous valve regulation. However, in actual operation, the failure rate of proportional valves is relatively high. Once the proportional valve fails, it will cause fluctuations in the valve regulation of the high-pressure bypass pressure reducing valve (BP), thereby affecting the stability of the boiler operating pressure. In severe cases, it may force the boiler to be shut down for maintenance, resulting in economic losses.

[0004] To address these issues, some existing technologies have proposed a dual proportional valve redundancy design. This involves using two servo proportional valves in parallel, with automatic switching in case of failure achieved via a switching solenoid valve. However, this switching triggering mechanism relies on a fault signal from the proportional valve or the switching circuit itself, making it a passive response. When the switching solenoid valve fails, "no feedback signal is reported, the monitoring system cannot detect and eliminate the fault in time, and the entire hydraulic control system will operate with significant safety hazards." In other words, when the fault occurs in the detection circuit itself or the proportional valve fails to output a fault signal normally, the system will be unable to switch in time, resulting in a detection blind spot.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a redundant regulating actuator for a high-pressure bypass pressure reducing valve, which can avoid boiler operation fluctuations or shutdown losses caused by proportional valve failure, thereby improving the safety and economy of boiler operation.

[0007] To achieve the above objectives / to solve the above technical problems, the present invention is implemented using the following technical solution: an actuator for adjusting the opening degree of a pressure reducing valve, comprising: a PLC controller, a hydraulic system, a cylinder and a displacement sensor, wherein the displacement sensor is connected to the valve stem of the pressure reducing valve for detecting the opening degree of the pressure reducing valve and outputting a feedback signal, and the piston rod of the cylinder is connected to the valve stem of the pressure reducing valve via a coupling. The hydraulic system includes a first hydraulic channel and a second hydraulic channel connected in parallel, as well as a pilot control directional valve. One end of the pilot control directional valve is connected to the first hydraulic channel and the second hydraulic channel respectively, and the other end of the pilot control directional valve is connected to the oil cylinder. The control end of the pilot control directional valve is externally connected to a solenoid directional valve, which is used to control the master-slave switching of the first hydraulic channel and the second hydraulic channel. The PLC controller is electrically connected to the displacement sensor and the solenoid directional valve. The PLC controller is used to receive external given signals and feedback signals from the displacement sensor. When the deviation between the given signal and the feedback signal exceeds the set threshold, it determines that the proportional valve of the current hydraulic channel is faulty and controls the solenoid directional valve to switch the pilot control directional valve and put the proportional valve of the backup hydraulic channel into active control.

[0008] Furthermore, the first hydraulic channel has a second manual shut-off valve and a first proportional valve connected sequentially on the oil inlet path, and a first proportional valve and a first manual shut-off valve connected sequentially on the oil return path. The second hydraulic channel has a fourth manual shut-off valve and a second proportional valve connected sequentially to its inlet path, and a second proportional valve and a third manual shut-off valve connected sequentially to its return path.

[0009] Furthermore, the inlet of the second manual shut-off valve is connected to the inlet channel of the hydraulic system, the outlet of the second manual shut-off valve is connected to the P port of the first proportional valve, the A and B ports of the first proportional valve are respectively connected to the pilot control directional valve, the T port of the first proportional valve is connected to the inlet of the first manual shut-off valve, and the outlet of the first manual shut-off valve is connected to the return channel of the hydraulic system.

[0010] Furthermore, the inlet of the fourth manual shut-off valve is connected to the inlet channel of the hydraulic system, the outlet of the fourth manual shut-off valve is connected to the P port of the second proportional valve, the A and B ports of the second proportional valve are respectively connected to the pilot control directional valve, the T port of the second proportional valve is connected to the inlet of the third manual shut-off valve, and the outlet of the third manual shut-off valve is connected to the return channel of the hydraulic system.

[0011] Furthermore, the hydraulic system's oil inlet channel is equipped with an oil inlet shut-off valve and a fine filter in sequence along the oil flow direction.

[0012] Furthermore, a check valve is installed on the return oil passage of the hydraulic system.

[0013] Furthermore, the working medium of the hydraulic system is high-pressure anti-wear hydraulic oil with a rated pressure of 14MPa.

[0014] Furthermore, the threshold is set at 10%.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: 1. This invention monitors the actual opening degree of the pressure reducing valve in real time using a displacement sensor and continuously compares it with a given command. Based on the deviation threshold, it actively determines whether the proportional valve is faulty, thus realizing the active detection of proportional valve faults. Two hydraulic channels are connected in parallel, and the electromagnetic directional valve is controlled by a PLC controller to switch the hydraulic channels by the pilot control directional valve, putting the proportional valve of the backup hydraulic channel into use and isolating the faulty proportional valve, thereby realizing the master-slave switching of the hydraulic channels.

[0016] 2. When the opening deviation of the pressure reducing valve exceeds 10%, the PLC controller automatically triggers the switching program, putting the standby proportional valve into active control. Simultaneously, the faulty proportional valve is isolated via a pilot-controlled directional valve. The switching process requires no manual intervention, and the pressure reducing valve's opening control quickly returns to normal, ensuring stable boiler pressure and avoiding the risk of boiler shutdown due to proportional valve failure, thus improving overall safety. Furthermore, the isolated proportional valve can be physically isolated from the hydraulic system by closing the corresponding manual shut-off valve, allowing for online replacement of the faulty proportional valve without shutdown, thereby improving boiler operating efficiency. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, 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 disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a hydraulic schematic diagram of the present invention.

[0019] In the diagram: 1. Oil inlet shut-off valve; 2. Fine filter; 3. First manual shut-off valve; 4. Second manual shut-off valve; 5. First proportional valve; 6. Third manual shut-off valve; 7. Fourth manual shut-off valve; 8. Second proportional valve; 9. Solenoid directional valve; 10. Oil cylinder; 11. Displacement sensor; 12. Pressure reducing valve; 13. Pilot-operated directional valve; 14. Check valve. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present application or its application or use. Example 1

[0021] like Figure 1 As shown, this embodiment provides a redundant regulating actuator for a high-pressure bypass pressure reducing valve. The actuator is used to adjust the opening degree of the pressure reducing valve 12 and includes: a PLC controller, a hydraulic system, a cylinder 10 and a displacement sensor 11. The displacement sensor 11 is connected to the valve stem of the pressure reducing valve 12 and is used to detect the opening degree of the pressure reducing valve 12 and output a feedback signal. The piston rod of the cylinder 10 is connected to the valve stem of the pressure reducing valve 12 through a coupling. The hydraulic system includes a first hydraulic channel and a second hydraulic channel connected in parallel, as well as a pilot control directional valve 13. One end of the pilot control directional valve 13 is connected to the first hydraulic channel and the second hydraulic channel respectively, and the other end of the pilot control directional valve 13 is connected to the oil cylinder 10. The control end of the pilot control directional valve 13 is externally connected to a solenoid directional valve 9, which is used to control the master-slave switching of the first hydraulic channel and the second hydraulic channel. The PLC controller is electrically connected to the displacement sensor 11 and the solenoid directional valve 9. The PLC controller is used to receive external given signals and feedback signals from the displacement sensor 11. When the deviation between the given signal and the feedback signal exceeds the set threshold, it determines that the proportional valve of the current hydraulic channel is faulty and controls the solenoid directional valve 9 to switch the pilot control directional valve 13, putting the proportional valve of the backup hydraulic channel into active control.

[0022] This application is used to control the high-pressure bypass system of a boiler to improve the safety of boiler operation. A displacement sensor 11 is installed on the valve stem of the pressure reducing valve 12 to detect the actual opening stroke of the pressure reducing valve 12 in real time and send the displacement feedback signal to the PLC controller. When the boiler is running, the PLC controller receives the valve opening command signal from the boiler main control system. The PLC controller performs internal calculations and outputs control current to the proportional valve currently in active control mode, thereby driving the hydraulic cylinder 10 to move. This causes the actual opening of the pressure reducing valve 12 to change according to the given value. At the same time as the pressure reducing valve 12 moves, the displacement sensor 11 located on its valve stem actively transmits a feedback signal to the PLC controller. The PLC controller compares the given signal with the feedback signal. When the deviation between the two exceeds a set threshold, it determines that the proportional valve in the current hydraulic channel is faulty and controls the solenoid directional valve 9 to move. This causes the pilot control directional valve 13 to switch the hydraulic channel, putting the proportional valve in the backup hydraulic channel into use and isolating the proportional valve in the faulty channel. This achieves master-slave switching of the hydraulic channel, improving the safety of boiler operation. Since the proportional valve in the faulty channel is isolated, the faulty proportional valve can be replaced online without stopping the boiler, thus improving boiler operating efficiency.

[0023] The first hydraulic channel has a second manual shut-off valve 4 and a first proportional valve 5 connected in sequence on the oil inlet path, and a first proportional valve 5 and a first manual shut-off valve 3 connected in sequence on the oil return path. The second hydraulic channel has a fourth manual shut-off valve 7 and a second proportional valve 8 connected sequentially on the oil inlet path, and a second proportional valve 8 and a third manual shut-off valve 6 connected sequentially on the oil return path.

[0024] When the proportional valve of the corresponding hydraulic channel is isolated by the pilot control directional valve 13 and needs to be replaced online, assuming that the first proportional valve 5 is isolated due to failure, the first manual shut-off valve 3 and the second manual shut-off valve 4 are manually closed to physically isolate the first proportional valve 5 from the hydraulic system, thereby facilitating replacement; if the second proportional valve 8 is isolated due to failure, the third manual shut-off valve 6 and the fourth manual shut-off valve 7 are manually closed.

[0025] The inlet of the second manual shut-off valve 4 is connected to the oil inlet channel of the hydraulic system, the outlet of the second manual shut-off valve 4 is connected to the P port of the first proportional valve 5, the A port and B port of the first proportional valve 5 are respectively connected to the pilot control directional valve 13, the T port of the first proportional valve 5 is connected to the inlet of the first manual shut-off valve 3, and the outlet of the first manual shut-off valve 3 is connected to the return oil channel of the hydraulic system.

[0026] The inlet of the fourth manual shut-off valve 7 is connected to the oil inlet channel of the hydraulic system, the outlet of the fourth manual shut-off valve 7 is connected to the P port of the second proportional valve 8, the A and B ports of the second proportional valve 8 are respectively connected to the pilot control directional valve 13, the T port of the second proportional valve 8 is connected to the inlet of the third manual shut-off valve 6, and the outlet of the third manual shut-off valve 6 is connected to the return oil channel of the hydraulic system.

[0027] The hydraulic system has an inlet shut-off valve 1 and a fine filter 2 installed sequentially along the oil flow direction in the oil inlet channel.

[0028] The pressure oil source is filtered sequentially through the inlet shut-off valve 1 and the fine filter 2 to obtain clean pressure oil. The outlet of the fine filter 2 is divided into two paths: the first path is connected to the pressure oil port P of the first proportional valve 5 through the second manual shut-off valve 4. When the hydraulic cylinder 10 is extended, the hydraulic oil flows out from port A of the first proportional valve 5 to the pilot control directional valve 13, and finally flows into the rodless chamber of the hydraulic cylinder 10. The return oil from the rod chamber of the hydraulic cylinder 10 flows into port B of the first proportional valve 5 through the pilot control directional valve 13, and flows back to the oil tank from port T through the first manual shut-off valve 3. When the hydraulic cylinder 10 is retracted, the hydraulic oil flows out from port B of the first proportional valve 5 and returns from port A.

[0029] The second path connects to the pressure port P of the second proportional valve 8 via the fourth manual shut-off valve 7, driving the cylinder 10 to extend. Hydraulic oil flows from port A of the second proportional valve 8 to the pilot control directional valve 13, and finally flows into the rodless chamber of the cylinder 10. The return oil from the rod chamber of the cylinder 10 flows into port B of the second proportional valve 8 through the pilot control directional valve 13, and flows back to the oil tank from port T through the third manual shut-off valve 6. When the cylinder 10 retracts, hydraulic oil flows out from port B of the second proportional valve 8 and returns from port A.

[0030] Another control oil circuit is connected to the solenoid directional valve 9, which is used to introduce hydraulic oil into the pilot control directional valve 13, push its valve core to move, and thus switch the hydraulic channel.

[0031] A check valve 14 is installed on the return oil passage of the hydraulic system.

[0032] One-way valve 14 is located in the return oil circuit to maintain system back pressure.

[0033] The working medium of the hydraulic system is high-pressure anti-wear hydraulic oil with a rated pressure of 14MPa. Example 2

[0034] Fault detection and automatic switching process: Using the first hydraulic channel as the active control loop, during normal boiler operation, the PLC controller continuously compares the given signal with the actual opening stroke fed back by the displacement sensor 11, and calculates the deviation between the two. When the deviation exceeds 10%, the PLC controller determines that the first proportional valve 5 under active control has malfunctioned.

[0035] At this time, the PLC controller performs the following operations: Issue a fault alarm for the first proportional valve 5; The PLC controller sends a signal to energize the solenoid directional valve 9, which in turn controls the directional valve 13 to switch its operation. After the pilot control directional valve 13 switches, the A and B ports of the first proportional valve 5 are isolated, and the A and B ports of the second proportional valve 8 are connected to the oil cylinder 10 through the pilot control directional valve 13, and the second proportional valve 8 switches to the active control state. At the same time, the PLC controller immediately outputs control current to the second proportional valve 8 to continue closed-loop regulation of the pressure reducing valve 12.

[0036] The entire switching process is rapid, and the opening control of the pressure reducing valve 12 is basically unaffected, resulting in stable boiler pressure. After the switch, the first manual shut-off valve 3 and the second manual shut-off valve 4 are manually closed, and the first proportional valve 5 is completely isolated. Maintenance personnel can disassemble the first proportional valve 5 for inspection or replacement while the boiler is operating normally, without having to shut down the boiler.

[0037] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to explain the relative positional relationship and movement between components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. These terms are used only for the convenience of describing this application and for simplifying the description, and are not intended to 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 limiting this application.

[0038] Furthermore, the terms "first," "second," etc., 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. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0040] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A redundant regulating actuator for a high-pressure bypass pressure reducing valve, the actuator being used to regulate the opening degree of the pressure reducing valve (12), characterized in that, include: The system includes a PLC controller, a hydraulic system, a cylinder (10), and a displacement sensor (11). The displacement sensor (11) is connected to the valve stem of a pressure reducing valve (12) to detect the opening degree of the pressure reducing valve (12) and output a feedback signal. The piston rod of the cylinder (10) is connected to the valve stem of the pressure reducing valve (12) via a coupling. The hydraulic system includes a first hydraulic channel and a second hydraulic channel connected in parallel, and a pilot control directional valve (13). One end of the pilot control directional valve (13) is connected to the first hydraulic channel and the second hydraulic channel respectively, and the other end of the pilot control directional valve (13) is connected to the oil cylinder (10). The control end of the pilot control directional valve (13) is externally connected to an electromagnetic directional valve (9). The electromagnetic directional valve (9) is used to control the master-slave switching of the first hydraulic channel and the second hydraulic channel. The PLC controller is electrically connected to the displacement sensor (11) and the solenoid directional valve (9). The PLC controller is used to receive external given signals and feedback signals from the displacement sensor (11). When the deviation between the given signal and the feedback signal exceeds the set threshold, it determines that the proportional valve of the current hydraulic channel is faulty and controls the solenoid directional valve (9) to switch the pilot control directional valve (13) and put the proportional valve of the backup hydraulic channel into active control.

2. The redundant regulating actuator for a high-pressure bypass pressure reducing valve according to claim 1, characterized in that: The first hydraulic channel has a second manual shut-off valve (4) and a first proportional valve (5) connected in sequence on the oil inlet path, and a first proportional valve (5) and a first manual shut-off valve (3) connected in sequence on the oil return path. The second hydraulic channel has a fourth manual shut-off valve (7) and a second proportional valve (8) connected in sequence on the oil inlet path, and a second proportional valve (8) and a third manual shut-off valve (6) connected in sequence on the oil return path.

3. The redundant regulating actuator for a high-pressure bypass pressure reducing valve according to claim 2, characterized in that: The inlet of the second manual shut-off valve (4) is connected to the inlet channel of the hydraulic system, the outlet of the second manual shut-off valve (4) is connected to the P port of the first proportional valve (5), the A port and B port of the first proportional valve (5) are connected to the pilot control directional valve (13) respectively, the T port of the first proportional valve (5) is connected to the inlet of the first manual shut-off valve (3), and the outlet of the first manual shut-off valve (3) is connected to the return channel of the hydraulic system.

4. A redundant regulating actuator for a high-pressure bypass pressure reducing valve according to claim 2, characterized in that: The inlet of the fourth manual shut-off valve (7) is connected to the inlet channel of the hydraulic system, the outlet of the fourth manual shut-off valve (7) is connected to the P port of the second proportional valve (8), the A port and B port of the second proportional valve (8) are respectively connected to the pilot control directional valve (13), the T port of the second proportional valve (8) is connected to the inlet of the third manual shut-off valve (6), and the outlet of the third manual shut-off valve (6) is connected to the return channel of the hydraulic system.

5. A redundant regulating actuator for a high-pressure bypass pressure reducing valve according to claim 1, characterized in that: The hydraulic system has an oil inlet shut-off valve (1) and a fine filter (2) arranged sequentially along the oil flow direction on the oil inlet channel.

6. A redundant regulating actuator for a high-pressure bypass pressure reducing valve according to claim 1, characterized in that: The hydraulic system is equipped with a check valve (14) on the return oil passage.

7. A redundant regulating actuator for a high-pressure bypass pressure reducing valve according to claim 1, characterized in that: The working medium of the hydraulic system is high-pressure anti-wear hydraulic oil with a rated pressure of 14 MPa.

8. A redundant regulating actuator for a high-pressure bypass pressure reducing valve according to claim 1, characterized in that: The set threshold is 10%.

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