Four-extraction high-emission steam extraction check valve control pipeline of steam turbine

Abstract

The utility model belongs to the technical field of steam turbines, and particularly relates to a four-extraction high-emission steam extraction check valve control pipeline of a steam turbine. Comprising a main control loop which is used for controlling a gas source so as to open and close a steam extraction check valve; one end of the bypass control loop is communicated with an air source, and the other end of the bypass control loop is communicated with the exhaust end of the first electromagnetic valve in the main control loop, so that the steam extraction check valve is opened and closed when the first electromagnetic valve is powered off. When the first electromagnetic valve breaks down and loses power, the outlet is communicated with the exhaust port, and an air source of the second electromagnetic valve enters from the outlet and continues to act on the check valve, so that normal opening of the check valve is guaranteed, and safe operation of a unit is not affected.

Description

Technical Field

[0001] This utility model belongs to the field of steam turbine technology, and specifically relates to a control pipeline for a four-stage high-efficiency exhaust steam non-return valve of a steam turbine. Background Technology

[0002] During normal operation of the turbine unit, the fourth-stage extraction steam supplies steam to the A / B turbines, deaerator, and auxiliary steam header. An electrically operated isolation valve and two pneumatically controlled non-return valves are installed on the fourth-stage extraction pipeline near the turbine. The non-return valves are installed before and after the electrically operated valve, respectively. The purpose of the non-return valves is to quickly close interlocked when the main steam valve closes due to a power grid or turbine failure, cutting off the extraction steam pipeline and preventing steam backflow into the turbine, which could lead to turbine overspeed and water hammer accidents. These are also key pieces of equipment on the fourth-stage extraction pipeline. A non-return valve is installed on the high-pressure exhaust pipeline. For example... Figure 1 As shown, the pneumatic non-return valve's air supply comes from the instrumentation compressed air pipeline. After pressure reduction and filtration, the compressed air is connected to the non-return valve and controlled by a solenoid valve. When the solenoid valve is energized, it connects the pneumatic non-return valve's control air supply circuit, and the non-return valve opens. If the solenoid valve loses power or the air supply pipeline leaks, it will cut off or reduce the control air supply pressure, causing the extraction steam non-return valve to close (close slightly), reducing the steam supply flow.

[0003] Given the importance of the fourth extraction and high-pressure exhaust systems, it is essential to ensure that the extraction non-return valves remain open during normal unit operation. Simultaneously, to prevent the non-return valves from closing due to electrical circuits or gas supply lines, thus affecting safe unit operation, the control systems for the fourth extraction and high-pressure exhaust non-return valves have been improved and optimized. Utility Model Content

[0004] The purpose of this utility model is to provide a control pipeline for the high-efficiency exhaust steam non-return valve of a steam turbine, which aims to connect the outlet of solenoid valve one with the exhaust port when solenoid valve one fails to power, so that the air source of solenoid valve two can enter through this connection and continue to act on the non-return valve, ensuring the normal opening of the non-return valve.

[0005] To solve the above-mentioned technical problems, this utility model provides a control pipeline for the four-stage high-efficiency exhaust steam non-return valve of a steam turbine, comprising:

[0006] The main control circuit controls the gas source to open and close the extraction non-return valve.

[0007] A bypass control circuit is provided, with one end connected to the gas source and the other end connected to the exhaust end of solenoid valve one in the main control circuit, so as to ensure that the extraction non-return valve can be opened and closed when solenoid valve one is de-energized.

[0008] Preferably, the main control circuit includes: a secondary valve, a filter pressure reducing valve, a solenoid valve, and a manual test valve; the gas source is connected to the extraction steam non-return valve after passing through the secondary valve, the filter pressure reducing valve, and the solenoid valve in series, and the manual test valve is also bypassed between the solenoid valve and the extraction steam non-return valve.

[0009] Preferably, the bypass control circuit includes: a second secondary valve and a second solenoid valve; the second secondary valve and the second solenoid valve are connected in series, and the inlet end of the second secondary valve is connected to the air source, and the outlet end of the second solenoid valve is connected to the exhaust end of the first solenoid valve.

[0010] Preferably, the bypass control circuit is installed above the main control circuit to ensure that impurities in the pipeline can be isolated and discharged through the filter pressure reducing valve on the main control circuit.

[0011] Preferably, it also includes a primary valve, which is installed before the air inlet of the manual test valve.

[0012] Preferably, the control power supplies for the first solenoid valve and the second solenoid valve are respectively connected to the power supply through two independent air switches in the thermal control relay power panel.

[0013] Preferably, the pipes in both the main control circuit and the bypass control circuit are made of stainless steel.

[0014] Preferably, it also includes a DCS control system for controlling the opening and closing of the main control loop and the bypass control loop.

[0015] Compared with the prior art, this utility model has the following advantages:

[0016] This invention modifies the air supply control of the extraction steam non-return valve to be simultaneously controlled by solenoid valves one and two, but the two solenoid valves are connected in series in the air supply pipeline. During normal operation, both solenoid valves one and two are energized, opening the air supply path. The air supply controlled by solenoid valve one goes directly to the extraction steam non-return valve, causing it to open. The outlet of solenoid valve two is connected to the exhaust port of solenoid valve one. When solenoid valve one is energized, its outlet and exhaust port are blocked, and the air supply path to solenoid valve two is blocked at one point. Therefore, the non-return valve is actually controlled by solenoid valve one. When solenoid valve one malfunctions and loses power, its outlet and exhaust port are reconnected, allowing the air supply to solenoid valve two to enter and continue acting on the non-return valve, ensuring its normal opening and not affecting the safe operation of the unit. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the existing four-stage high-efficiency exhaust steam non-return valve control pipeline.

[0018] Figure 2This is a schematic diagram of the control pipeline for the four-stage high-efficiency exhaust steam non-return valve of this utility model.

[0019] In the diagram: 1-Secondary valve one, 2-Filter pressure reducing valve, 3-Solenoid valve one, 4-Manual test valve, 5-Secondary valve two, 6-Solenoid valve two, 7-Primary valve. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0021] like Figure 2 As shown, this utility model embodiment provides a control pipeline for the non-return valve of the fourth extraction high-pressure exhaust steam of a steam turbine, including:

[0022] The main control circuit controls the gas source to open and close the extraction non-return valve.

[0023] The bypass control circuit has one end connected to the gas source and the other end connected to the exhaust end of solenoid valve 3 in the main control circuit, so as to ensure that the extraction non-return valve can be opened and closed when solenoid valve 3 is de-energized.

[0024] The main control circuit includes: secondary valve 1, filter pressure reducing valve 2, solenoid valve 3 and manual test valve 4; the gas source is connected to the extraction steam non-return valve after passing through the secondary valve 1, filter pressure reducing valve 2 and solenoid valve 3 in series. That is, the gas outlet of solenoid valve 3 is connected to the pneumatic non-return valve on the extraction steam non-return valve, and there is also a bypass between solenoid valve 3 and extraction steam non-return valve 4.

[0025] The bypass control circuit includes: secondary valve 25 and solenoid valve 26; secondary valve 25 and solenoid valve 26 are connected in series, and the air inlet of secondary valve 25 is connected to the air source, and the air outlet of solenoid valve 26 is connected to the exhaust outlet of solenoid valve 3.

[0026] The bypass control circuit is installed above the main control circuit to ensure that impurities in the pipeline can be isolated and discharged through the filter pressure reducing valve 2 on the main control circuit.

[0027] It also includes a primary valve 7, which is installed before the air inlet of the manual test valve 4.

[0028] The control power supplies for solenoid valve 3 and solenoid valve 6 are respectively connected to the power supply through two independent air switches in the thermal control relay power panel.

[0029] The piping in both the main control circuit and the bypass control circuit is made of stainless steel.

[0030] It also includes a DCS control system, which is used to control the opening and closing of the main control loop and the bypass control loop.

[0031] This utility model also includes the following working principle:

[0032] 1) Retain the original electrical control circuit, i.e., the main control circuit: Solenoid valve 1 operates in an energized state, meaning that after the power is turned on, solenoid valve 1 actuates, connecting the control air supply circuit of the pneumatic check valve, and the check valve opens. Once solenoid valve 1 is de-energized, it cuts off the control air supply, causing the extraction steam check valve to close. The control signal for solenoid valve 1 is taken from the opening command signal of the fourth extraction check valve in the DCS control system.

[0033] 2) Add a bypass control circuit for the solenoid valve: Solenoid valve two operates in the same state as solenoid valve one (energized). The control power for solenoid valve two is taken from the thermal control power cabinet, and a 220VAC power cable is laid to the local control solenoid valve. Another command signal to open the extraction steam check valve is retrieved from the DCS and transmitted via a transition cable from the cabinet to the lower end of the power cabinet, where it is connected in series into the power circuit of solenoid valve two to control its operation.

[0034] 3) At the same time, make slight modifications to the original air source control pipeline; connect the exhaust port (P) of solenoid valve one to the outlet (A) of solenoid valve two, while leaving the outlet of solenoid valve one unchanged. This will create a series circuit between the air source pipelines of the two solenoid valves.

[0035] 4) Furthermore, an additional gas source control pipeline is added; a bypass is added before the original extraction steam non-return valve control gas source secondary valve, one path connecting to the original control gas source pipeline, and the other path connecting to the newly added gas source control pipeline. After connecting to the secondary valve, the pipeline is connected to the inlet (E) of solenoid valve two, and the outlet (A) of solenoid valve two is connected to the exhaust port (P) of solenoid valve one. The connection of the new gas source pipeline includes the connection between the secondary valve and solenoid valve two.

[0036] 5) The newly added gas source control circuit must be installed above the original pipeline to ensure that impurities in the pipeline can be isolated and discharged through the original pipeline's filter and pressure reducing valve. Additionally, a primary valve is added before the manual test valve of the extraction steam check valve. Because the original gas control pipelines were all copper pipes with bulged ends, special tools were required for operation, and any cracks in the copper pipes could not be dealt with promptly. All gas control pipelines will be replaced with stainless steel pipe connections, with additional connectors at each interface. The stainless steel pipes will be connected using a welding process with flexible joints.

[0037] The above description is only a description of the preferred embodiment of the present utility model and is not intended to limit the scope of the present utility model in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A control line for a steam turbine fourth extraction high pressure extraction steam non-return valve, characterized in that, The utility model relates to a kind of steam extraction check valve control system, including: Main control loop, by the main control loop, steam source is controlled to realize the opening and closing of steam extraction check valve; Bypass control loop, one end of the bypass control loop is communicated with steam source, the other end is communicated with the exhaust end of electromagnetic valve one (3) in the main control loop, to ensure that steam extraction check valve is opened and closed under the de-energization of electromagnetic valve one (3).

2. A control conduit for a steam turbine fourth high-pressure extraction bleed-steam non-return valve as claimed in claim 1, characterised in that, The main control loop includes: secondary valve one (1), filter pressure reducing valve (2), electromagnetic valve one (3) and manual test valve (4);Steam source is sequentially connected to steam extraction check valve through the secondary valve one (1), filter pressure reducing valve (2) and electromagnetic valve one (3) in series, and there is manual test valve (4) between electromagnetic valve one (3) and steam extraction check valve.

3. A control conduit for a steam turbine fourth high-pressure extraction bleed-steam non-return valve as claimed in claim 1, characterised in that, The bypass control loop includes: secondary valve two (5) and electromagnetic valve two (6);Secondary valve two (5) and electromagnetic valve two (6) are in series, and the air inlet end of secondary valve two (5) is communicated with steam source, and the air outlet end of electromagnetic valve two (6) is communicated with the exhaust end of electromagnetic valve one (3).

4. A control conduit for a steam turbine fourth high-pressure extraction bleed-steam non-return valve as claimed in claim 2, characterised in that, The bypass control loop is installed above the main control loop, so that impurities in the pipeline can be isolated and discharged by the filter pressure reducing valve (2) on the main control loop.

5. A control conduit for a steam turbine fourth high-pressure extraction bleed-steam non-return valve as claimed in claim 2, characterised in that, It also includes primary valve (7), which is installed in front of the air inlet end of the manual test valve (4).

6. A control conduit for a steam turbine fourth high-pressure extraction bleed-steam non-return valve as claimed in claim 3, characterised in that, The control power supply of electromagnetic valve one (3) and electromagnetic valve two (6) is connected to the power supply through two independent air switches in the heat control relay power supply panel.

7. A control conduit for a steam turbine fourth high-pressure extraction bleed-steam non-return valve as claimed in claim 1, characterized in that The pipelines in the main control loop and the bypass control loop are made of stainless steel.

8. A control conduit for a steam turbine fourth high-pressure stage extraction steam non-return valve according to any one of claims 1 to 7, characterised in that, It also includes a DCS control system for opening and closing control of the main control loop and the bypass control loop.

Images