Air source control loop of emergency pneumatic valve for thermal power plant

Abstract

The utility model relates to the technical field of thermal power plants, and provides a gas source control loop of an emergency pneumatic valve for a thermal power plant. Comprising a compressed air pipeline used for conveying compressed air; the main electromagnetic valve is a two-position three-way electromagnetic valve and is arranged on a compressed air pipeline, an air inlet is connected with compressed air, an air outlet is connected with an air cylinder of the emergency pneumatic valve, and an exhaust port is connected with the position keeping electromagnetic valve; the position keeping electromagnetic valve is a two-position three-way electromagnetic valve, and an exhaust port of the position keeping electromagnetic valve is connected with an exhaust port of the main electromagnetic valve in series; and the main electromagnetic valve and the position keeping electromagnetic valve are configured to keep the exhaust port closed in a power-on state and open the exhaust port in a power-off state. By means of the dual-redundancy structure of the main electromagnetic valve and the position-keeping electromagnetic valve which are arranged in series, when the main electromagnetic valve is abnormally powered off and exhausts, the position-keeping electromagnetic valve can stop exhausting, and therefore the risk of misoperation of the emergency pneumatic valve is avoided, and equipment safety is guaranteed.

Description

Technical Field

[0001] This application relates to the field of thermal power plant technology, specifically to a pneumatic control circuit for an emergency pneumatic valve used in thermal power plants. Background Technology

[0002] Emergency pneumatic valves are widely used in thermal power plants. They are powered by compressed air (0.4-0.8 MPa) and come in two forms: emergency shut-off valves and emergency open valves.

[0003] The emergency shut-off valve (FC, which is an air-to-open type, meaning the pneumatic valve opens when air is supplied and closes when air is lost) is controlled by a solenoid valve. Under normal circumstances, the solenoid valve is energized, compressed air enters the cylinder, and the emergency shut-off valve opens. In an emergency, the control system automatically sends a command to cut off the power to the solenoid valve. After the solenoid valve loses power, it shuts off the air supply to the pneumatic valve and vents the compressed air from the cylinder. The pneumatic valve then closes due to the loss of its air supply.

[0004] The emergency opening valve (FO, which operates as a pneumatic shut-off valve, meaning it closes when air is supplied and opens when air is lost) is controlled by a solenoid valve. Under normal circumstances, the solenoid valve is energized, compressed air enters the cylinder, and the emergency shut-off valve closes. In an emergency, the control system automatically sends a command to cut off the power to the solenoid valve. After the solenoid valve loses power, it shuts off the air supply to the pneumatic valve and vents the compressed air from the cylinder. The pneumatic valve then opens due to the loss of its air supply.

[0005] The aforementioned emergency shut-off valve and emergency open valve are both controlled by solenoid valves. During normal operation, the solenoid valves are energized. If the power supply circuit of the solenoid valve or the solenoid valve itself malfunctions, the solenoid valve will lose power and shut off the air supply to the pneumatic valve and vent the compressed air in the cylinder, causing the emergency shut-off valve and emergency open valve to malfunction, damaging the equipment and causing an accident. Summary of the Invention

[0006] In view of this, the present application provides a pneumatic control circuit for an emergency pneumatic valve in a thermal power plant to solve the problem of malfunction of the emergency shut-off valve or emergency open valve caused by a power supply circuit failure or solenoid valve failure.

[0007] An embodiment of this application provides a pneumatic control circuit for an emergency pneumatic valve in a thermal power plant, comprising:

[0008] Compressed air pipelines are used to transport compressed air;

[0009] The main solenoid valve is a two-position three-way solenoid valve, which is installed on the compressed air pipeline. The air inlet is connected to compressed air, the air outlet is connected to the cylinder of the emergency pneumatic valve, and the exhaust port is connected to the position-holding solenoid valve.

[0010] The position-holding solenoid valve is a two-position three-way solenoid valve, and its exhaust port is connected in series with the exhaust port of the main solenoid valve.

[0011] The main solenoid valve and the position-holding solenoid valve are configured to keep the exhaust port closed when energized and open when de-energized.

[0012] In one embodiment, the position-holding solenoid valve and the main solenoid valve are connected to different power sources.

[0013] In one embodiment, the control signal input terminals of the position-holding solenoid valve and the main solenoid valve are respectively connected to different digital output cards in the distributed control system.

[0014] In one embodiment, the main solenoid valve and the position-holding solenoid valve are two-position three-way solenoid valves of the same specification.

[0015] In one embodiment, the compressed air pipeline is further provided with an air filter pressure reducing valve, the output end of which is connected to the air inlet end of the main solenoid valve.

[0016] In one embodiment, the compressed air pipe is also equipped with a pressure gauge.

[0017] In one embodiment, the emergency pneumatic valve is an emergency shut-off valve or an emergency open valve.

[0018] This application provides an air source control circuit for an emergency pneumatic valve in a thermal power plant, comprising a compressed air pipeline for supplying compressed air; a main solenoid valve, a two-position three-way solenoid valve, mounted on the compressed air pipeline, with its inlet connected to compressed air, its outlet connected to the cylinder of the emergency pneumatic valve, and its exhaust port connected to a position-holding solenoid valve; and a position-holding solenoid valve, also a two-position three-way solenoid valve, with its exhaust port connected in series with the exhaust port of the main solenoid valve. The main solenoid valve and the position-holding solenoid valve are configured to keep their exhaust ports closed when energized and open when de-energized. By configuring the main solenoid valve and the position-holding solenoid valve in series with a dual-redundancy structure, when the main solenoid valve malfunctions and exhausts air, the position-holding solenoid valve can prevent exhaust, thereby avoiding the risk of malfunction of the emergency pneumatic valve and ensuring equipment safety. Attached Figure Description

[0019] 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.

[0020] Figure 1 This is a schematic diagram of a structure provided in an embodiment of this application;

[0021] In the diagram: 1-Compressed air pipeline, 2-Air filter pressure reducing valve, 3-Main solenoid valve, 4-Pressure gauge, 5-Emergency pneumatic valve, 6-Position holding solenoid valve. Detailed Implementation

[0022] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0023] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0024] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0025] like Figure 1 As shown in the figure, this application embodiment provides a pneumatic control circuit for an emergency pneumatic valve in a thermal power plant, including:

[0026] Compressed air pipeline 1, used for transporting compressed air;

[0027] The main solenoid valve 3 is a two-position three-way solenoid valve, which is installed on the compressed air pipeline 1. The air inlet is connected to compressed air, the air outlet is connected to the cylinder of the emergency pneumatic valve 5, and the exhaust port is connected to the position-holding solenoid valve 6.

[0028] The position-holding solenoid valve 6 is a two-position three-way solenoid valve, and its exhaust port C is connected in series with the exhaust port of the main solenoid valve 3.

[0029] The main solenoid valve 3 and the position-holding solenoid valve 6 are configured to keep the exhaust port closed when energized and open when de-energized.

[0030] In application, compressed air pipeline 1 can be made of stainless steel. The inlet end is connected to the compressed air main pipeline of the thermal power plant, and the outlet end is connected in series with air filter pressure reducing valve 2 and main solenoid valve 3. The pipeline diameter is designed to match the air consumption of pneumatic valve 5 to ensure that the air supply flow meets the valve's operating speed requirements.

[0031] In application, the main solenoid valve 3 is a two-position three-way direct-acting solenoid valve, which is normally energized (when energized, A→B is open and C is closed; when de-energized, B→C is open and A is closed).

[0032] In application, the position-holding solenoid valve 6 has the same structure as the main solenoid valve 3, and is normally energized (when energized, A→B is open and port C is closed; when de-energized, B→C is open and port A is closed). Its exhaust port C is directly connected to the atmosphere, forming a two-stage exhaust path.

[0033] This application embodiment uses a dual-redundant structure with a main solenoid valve and a position-holding solenoid valve configured in series. When the main solenoid valve malfunctions and discharges air, the position-holding solenoid valve can prevent the air from being discharged, thereby avoiding the risk of malfunction of the emergency pneumatic valve and ensuring equipment safety.

[0034] In one embodiment, the position-holding solenoid valve 6 and the main solenoid valve 3 are connected to different power sources.

[0035] In application, the power supply circuit of the main solenoid valve 3 can be connected to the #1 power cabinet, and the power supply circuit of the position-maintaining solenoid valve 6 can be connected to the #2 power cabinet. The two power cabinets are powered by different bus sections of the plant power supply and are equipped with UPS uninterruptible power supplies.

[0036] This application's embodiments avoid the common-cause failure problem of simultaneous power loss of the main / position-holding solenoid valves due to a fault in the same power cabinet by using an independent power supply architecture. The physical isolation design of the power supply meets the minimum independence requirements of power industry safety regulations for redundant systems, fundamentally eliminating control failures caused by single-point failures in the power system.

[0037] In one embodiment, the control signal input terminals of the position-holding solenoid valve 6 and the main solenoid valve 3 are respectively connected to different digital output cards in the distributed control system.

[0038] In application, the control signal of the main solenoid valve 3 can be output from the DO card A1-1 of the DCS system, and the control signal of the position-holding solenoid valve 6 can be output from the DO card A2-1. The two cards are arranged on different racks. An emergency action trigger module is set in the DCS system. When an ESD (emergency shutdown) signal is received, a power-off command is sent to the main solenoid valve 3 and the position-holding solenoid valve 6 simultaneously. The response time difference is less than 50ms, ensuring that the exhaust passage is instantly fully open.

[0039] This application's embodiments effectively prevent erroneous signal synchronization caused by digital output card failures through physical isolation design of the control signal path. Hardware-level isolation in the distributed control system (DCS) significantly reduces the probability of common-mode failure in the control system.

[0040] In one embodiment, the main solenoid valve 3 and the position-holding solenoid valve 6 are two-position three-way solenoid valves of the same specification.

[0041] In one embodiment, the compressed air pipeline 1 is further provided with an air filter pressure reducing valve 2, the output end of which is connected to the air inlet end of the main solenoid valve 3.

[0042] In application, the air filter pressure reducing valve 2 can integrate a 5μm precision filter and a pilot-operated pressure reducing module. The inlet end is connected to the compressed air pipeline 1, and the outlet end is connected to the air inlet A of the main solenoid valve 3 through a metal rigid pipe. The output pressure is set to 0.2-0.4MPa (adjustable).

[0043] In one embodiment, the compressed air pipe 1 is further provided with a pressure gauge.

[0044] In one embodiment, the emergency pneumatic valve 5 is an emergency shut-off valve or an emergency open valve.

[0045] The working principle of this gas source control circuit is as follows:

[0046] Under normal operating conditions, compressed air pipeline 1 delivers compressed air from an external air source to air filter and pressure reducing valve 2. After filtration, purification, and pressure regulation, a stable air source is formed. At this time, the main solenoid valve 3 is energized, with its inlet A connected to its working port B. Compressed air enters the cylinder of the emergency pneumatic valve 5 through working port B. For the emergency shut-off valve FC, the cylinder is charged to keep the valve open; for the emergency open valve FO, the cylinder is charged to keep the valve closed. Simultaneously, the position-holding solenoid valve 6, connected in series in the exhaust passage, is also energized, with its exhaust port C remaining closed. The entire exhaust passage is blocked, ensuring stable air pressure within the cylinder.

[0047] In the event of an emergency, the distributed control system (DCS) synchronously cuts off the power to the main solenoid valve 3 and the position-holding solenoid valve 6. After the main solenoid valve 3 loses power, it switches to exhaust mode, with its working port B connected to its exhaust port C, allowing compressed air to be discharged from the cylinder. Simultaneously, the position-holding solenoid valve 6 loses power, and its exhaust port C fully opens, allowing gas in the cylinder to be discharged into the atmosphere sequentially through the exhaust ports C of both the main solenoid valve 3 and the position-holding solenoid valve 6. The cylinder of the emergency pneumatic valve 5 triggers a preset action due to pressure loss: the emergency shut-off valve FC closes, and the emergency open valve FO opens, achieving the system's safety protection function.

[0048] In non-emergency fault scenarios, such as abnormal power supply to the main solenoid valve 3 or valve body jamming, the main solenoid valve 3 may lose power abnormally and attempt to open the exhaust port C. At this time, the position-holding solenoid valve 6 remains normally energized, and its exhaust port C remains closed, forming a physical blocking layer. Compressed air in the cylinder cannot be discharged because the exhaust passage is doubly blocked, and the emergency pneumatic valve 5 maintains its original working state, thereby avoiding malfunction. This protection mechanism is achieved through the independent power supply design of the position-holding solenoid valve 6. Its power supply circuit is connected to a different power cabinet than that of the main solenoid valve 3, and the control signal is transmitted independently through different digital output cards of the DCS, completely eliminating the risk of common cause failure.

[0049] Air filter pressure reducing valve 2 continuously filters impurities and regulates the pressure of the input air source, preventing particulate matter from entering the solenoid valve and causing valve core jamming. Simultaneously, pressure gauge 4 monitors the air source pressure in real time after pressure reduction. This collaborative mechanism ensures air source quality and pressure stability, reducing system failure rate from the source.

[0050] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A pneumatic supply control circuit for an emergency pneumatic valve in a thermal power plant, characterized in that, include: Compressed air pipeline (1), used to transport compressed air; The main solenoid valve (3) is a two-position three-way solenoid valve, which is installed on the compressed air pipeline (1). The air inlet is connected to compressed air, the air outlet is connected to the cylinder of the emergency pneumatic valve (5), and the exhaust port is connected to the position-holding solenoid valve (6). The position-holding solenoid valve (6) is a two-position three-way solenoid valve, and its exhaust port is connected in series with the exhaust port of the main solenoid valve (3). The main solenoid valve (3) and the position-holding solenoid valve (6) are configured to keep the exhaust port closed when energized and open when de-energized.

2. The air source control circuit for an emergency pneumatic valve in a thermal power plant as described in claim 1, characterized in that, The position-holding solenoid valve (6) and the main solenoid valve (3) are respectively connected to different power sources.

3. The air source control circuit for an emergency pneumatic valve in a thermal power plant as described in claim 1, characterized in that, The control signal input terminals of the position-holding solenoid valve (6) and the main solenoid valve (3) are respectively connected to different digital output cards in the distributed control system.

4. The air source control circuit for an emergency pneumatic valve in a thermal power plant as described in claim 1, characterized in that, The main solenoid valve (3) and the position-holding solenoid valve (6) are two-position three-way solenoid valves of the same specifications.

5. The air source control circuit for an emergency pneumatic valve in a thermal power plant as described in claim 1, characterized in that, The compressed air pipeline (1) is also equipped with an air filter pressure reducing valve (2), the output end of which is connected to the air inlet end of the main solenoid valve (3).

6. The air source control circuit for an emergency pneumatic valve in a thermal power plant as described in claim 1, characterized in that, The compressed air pipeline (1) is also equipped with a pressure gauge.

7. The air source control circuit for an emergency pneumatic valve in a thermal power plant as described in claim 1, characterized in that, The emergency pneumatic valve (5) is an emergency shut-off valve or an emergency open valve.

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