A new emergency shutoff device

Abstract

The present invention discloses a novel emergency shut-off device; the device is arranged in the high-pressure fire-resistant oil EH system of the steam turbine, receives the shut-off command of the ETS system, and realizes the emergency shut-off of the steam turbine to protect the safety of the steam turbine. The device includes four AST solenoid valves arranged in series and parallel, and the AST solenoid valve and the ASP throttling assembly are fixed on the hydraulic integrated block through the plate-type stop valve 5. A one-way valve is provided at the oil inlet main pipe of the AST solenoid valve. The operation of each AST solenoid valve alone will not cause the emergency shut-off to malfunction, nor will it cause the emergency shut-off device to refuse to operate; by closing the plate-type stop valve 5, the throttling hole can be cleaned or replaced online. The pressure measuring component determines whether the device is in normal working condition by testing the pressure of each component and displaying the pressure level, and issues an alarm prompt for abnormal conditions.

Description

Technical Field

[0001] The present invention relates to the field of steam turbines, and more particularly to a novel emergency shutoff device. Background Art

[0002] The turbine's high-pressure fire-resistant oil hydraulic control system (EH) must provide basic turbine control, overspeed protection, and emergency trip functions. The EH hydraulic control system comprises an oil supply system, actuators, and an emergency trip system. Within this control system, the emergency trip system is a specialized device that detects turbine overspeed, abnormalities in key operating parameters (such as vibration, bearing temperature, and vacuum), and the activation of other safety systems. It automatically trips the turbine system to ensure safe unit shutdown. Therefore, the emergency trip system is a crucial component of the turbine's normal and safe operation. When it was first introduced, there was neither a theoretical basis for design nor practical operational experience, and the system was essentially a rote imitation.

[0003] During later operation and maintenance, the shortcomings and problems of the emergency trip system became increasingly prominent. For example, system failures could not be promptly repaired and replaced online, causing erroneous trips during normal operation tests, and the system had to operate "without shutdown" when it could not be shut down. Overspeeding could result in a serious accident, causing a runaway turbine accident. Users often suffered from anxiety and frustration. Due to design issues, traditional emergency trip systems often caused erroneous trips due to the operation of the test solenoid valve. Furthermore, during online testing, if a solenoid valve fault was detected, the system could not be replaced without shutting down the unit. Consequently, the system had to operate with the fault condition. Furthermore, during online testing, the choke often failed, causing changes in ASP pressure and making it impossible to perform online testing of the solenoid valve. Since the choke had to be repaired while the unit was shut down, the system had to be deactivated for testing without shutting down the unit. Therefore, without shutting down the unit, the system had to be deactivated for testing, forcing the unit to operate under constant fear. Therefore, the emergency trip system urgently needs to solve the problem of online system maintenance and replacement of hydraulic components without stopping the turbine during operation, eliminate false tripping, and completely solve the problem of the system working with "illness" to ensure the healthy and safe operation of the unit.

[0004] For example, a "steam turbine emergency shut-down system" disclosed in a Chinese patent document, with publication number CN206190335U, includes an isolation valve assembly and an EH system. The isolation valve assembly is arranged on the pipeline between the AST oil pipe and the pressure-free return oil pipe. The pressure-free return oil pipe is connected to the EH system tank via a pipeline, and the turbine oil safety oil is input into the upper chamber of the diaphragm valve assembly via the oil inlet pipe. The system also includes a spare diaphragm valve assembly, the upper chamber of the spare diaphragm valve assembly is connected to the turbine oil safety oil pipe, and the two ends of the spare diaphragm valve assembly are respectively connected to the ATS oil pipe and the pressure-free return oil pipe. The advantages of this system are to improve the reliability of the emergency shut-down system and prevent the occurrence of serious accidents such as overspeed of the unit; to achieve online non-stop fault elimination in the event of a single defect in the diaphragm valve assembly; and to improve the flexibility of equipment maintenance through the parallel operation of diaphragm valves, while reducing the unit downtime and improving the unit's operating efficiency and economic benefits. However, simply isolating and replacing a single solenoid valve through a diaphragm valve ignores the fact that under existing technology, if the throttling device fails, the oil outlet pipe is blocked but no pressure alarm occurs, which makes it difficult to meet the online maintenance needs under various conditions. Summary of the Invention

[0005] In view of the problems in the existing technology that the test solenoid valve is prone to causing false tripping, the solenoid valve cannot be replaced online due to fault, and the solenoid valve cannot be tested online when the throttle fails, the present invention provides a new type of emergency shut-off device; the device is arranged in the high-pressure fire-resistant oil EH system of the steam turbine, receives the shut-off command of the ETS system, and realizes the emergency shut-off of the steam turbine to protect the safety of the steam turbine. The device includes four AST solenoid valves arranged in series and parallel, and the AST solenoid valve and ASP throttling assembly are fixed to the hydraulic integrated block through a plate-type stop valve. A one-way valve is provided at the oil inlet main pipe of the AST solenoid valve. The operation of each AST solenoid valve alone will not cause the emergency shut-off to malfunction, nor will it cause the emergency shut-off device to refuse to operate; by closing the plate-type stop valve, the throttle hole can be cleaned or replaced online. The pressure measuring component determines whether the device is in normal working condition by testing the pressure of each component and displaying the pressure level, and issues an alarm prompt for abnormal conditions.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A new emergency shutoff device includes four sets of AST solenoid valves connected in series and parallel, two sets of OPC solenoid valves, and a pressure measuring assembly; the AST solenoid valves are assembled on the top of the hydraulic integrated block via a plate-type shutoff valve; the OPC solenoid valves are assembled on the top of the hydraulic integrated block; the pressure measuring assembly is arranged on the AST solenoid valves; the device also includes an ASP throttling assembly; the ASP throttling assembly is assembled on the hydraulic integrated block via a plate-type shutoff valve. The device is installed in the high-pressure fire-resistant oil EH system of the steam turbine, receives the shutoff command from the ETS system, and realizes emergency shutoff of the steam turbine to protect the safety of the steam turbine. The device includes four AST solenoid valves arranged in series and parallel, and the AST solenoid valves and the ASP throttling assembly are fixed to the hydraulic integrated block via a plate-type shutoff valve. A one-way valve is provided at the oil inlet main pipe of the AST solenoid valve. The individual operation of each AST solenoid valve will not cause the emergency shutoff to malfunction, nor will it cause the emergency shutoff device to refuse to operate; by closing the plate-type shutoff valve, the throttling hole can be cleaned or replaced online. The pressure measuring component tests the pressure of each component, determines whether the device is in normal working condition by displaying the pressure level, and issues an alarm for abnormal conditions.

[0008] Preferably, the AST oil inlet pipe is divided into three branches; the first branch is provided with an ASP throttling assembly, including a throttle hole K1 and a throttle hole K2; the second branch is provided with an AST solenoid valve AST-3 and an AST solenoid valve AST-4 in sequence; the third branch is provided with an AST solenoid valve AST-3 and an AST solenoid valve AST-4 in sequence; the AST oil inlet pipe is connected to two sets of OPC solenoid valves through a one-way valve;

[0009] The OPC oil inlet pipe is connected to two sets of OPC solenoid valves respectively;

[0010] The HP oil pipeline is divided into two branches. The first branch is connected to AST solenoid valve AST-1 and AST solenoid valve AST-2 through a one-way valve, and the second branch is connected to AST solenoid valve AST-3 and AST solenoid valve AST-4 through a one-way valve;

[0011] The series and parallel connection of the AST solenoid valves ensures that each AST solenoid valve will not cause other AST solenoid valves to malfunction or stop when operating alone. The one-way valve is set in the hydraulic manifold, effectively separating the hydraulic channels of the AST safety oil and the OPC safety oil, isolating the operations of the two and preventing them from affecting each other.

[0012] Preferably, a channel is provided between the throttle hole K1 and the throttle hole K2; the channel connects between the AST solenoid valve AST-1 and the AST solenoid valve AST-2; the channel connects between the AST solenoid valve AST-3 and the AST solenoid valve AST-4; and two sets of ASP pressure switches are provided between the channels. The two ASP pressure switches are used as the discriminant elements for testing whether the AST solenoid valve is operating normally. The pressure value of the pressure switch is taken from the intermediate pressure of the two throttle holes in the AST oil pipeline. By matching the diameters of the two throttle holes, the measured ASP pressure can be made equal to half of the AST pressure. When the AST solenoid valve is operating, the ASP pressure switch will display a high pressure or low pressure alarm signal. When a single AST solenoid valve is operating normally, the ASP pressure switch will not issue an alarm signal. If an alarm signal is output, it indicates that one or both of the two throttle holes are clogged and need to be cleaned.

[0013] Preferably, pressure measuring joints are provided at the top of the throttling assembly and the top of the AST solenoid valve respectively; by testing the internal pressure conditions of the throttling assembly and the AST solenoid valve, the blockage condition of the internal oil pipeline can be obtained, and online adjustment and maintenance can be performed according to the fault status.

[0014] Preferably, the hydraulic integrated block is provided with internal oil inlet and return channels for AST safety oil, OPC safety oil and ASP test oil; the hydraulic integrated block is also provided with an external interface; the oil inlet, oil return channels and external interface can transmit any signal instrument for use as monitoring or control signals.

[0015] Preferably, the oil inlet main pipe of the AST solenoid valve, the oil inlet main pipe of the OPC solenoid valve, and the test oil main pipe of the ASP throttling assembly are provided with a pressure switch; the oil inlet main pipe of the AST solenoid valve, the oil inlet main pipe of the OPC solenoid valve, and the test oil main pipe of the ASP throttling assembly are all provided with a pressure gauge; the oil inlet main pipe of the AST solenoid valve is provided with a pressure transmitter. The effectiveness and correctness of the solenoid valve action are indicated by the pressure gauge and the pressure switch, and abnormal operation is alarmed by the high and low pressure of the pressure switch. Preferably, the oil inlet main pipe of the AST solenoid valve and the oil inlet main pipe of the OPC solenoid valve are both provided with a one-way valve. The two one-way valves are installed in the hydraulic integrated block, effectively separating the hydraulic channels of the AST safety oil and the OPC safety oil.

[0016] Preferably, the plate-type stop valve is connected to a pressure gauge via the output interface of the pressure measuring assembly. The pressure gauge includes pressure indication marks for the effective open and closed valve positions. This ensures that the normal emergency shutoff function of the AST solenoid valve will not be affected by component failure during online maintenance or replacement.

[0017] Preferably, a sliding valve is installed on the plate-type stop valve; the sliding valve includes a valve plate, a valve stem and an indicator plate; the indicator plate is arranged on one side of the stop valve, and the valve plate is fixed to the indicator plate through the valve stem. The AST solenoid valve can be switched on and off by rotating the valve plate and the valve stem, and the indicator plate can indicate the switch position of the valve plate to prevent the valve stem from being injured or malfunctioning due to excessive force and stretching.

[0018] Preferably, the plate-type stop valve is provided with an open valve position stroke mark, a closed valve position stroke mark, and a mechanical limit device. The mechanical limit device is implemented by a limit screw, so that the valve position can be ensured to be fully opened and closed during online maintenance and replacement.

[0019] The beneficial effects of the present invention are mainly manifested in:

[0020] 1. Reliable design: The four AST solenoid valves are arranged in series and parallel, so that during the online test, the operation of any solenoid valve will not cause the unit's AST pressure to release and cause an accidental trip. At the same time, to prevent the unit from tripping due to the pressure release of a faulty solenoid valve during the test, each solenoid valve is relatively isolated during the test to ensure that there is no risk of any accidents.

[0021] 2. Allow online maintenance and replacement; once the test confirms that the solenoid valve is faulty, it can be repaired and replaced without stopping the machine due to the function of the isolation valve;

[0022] 3. The built-in throttle is removed and the isolation valve function is added. Once the throttle fails, it can be repaired and replaced online immediately. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the hydraulic oil system of the emergency trip device of the present invention;

[0024] Figure 2 It is a front view of the emergency shutoff device of the present invention;

[0025] In the picture:

[0026] 1-Hydraulic integrated block; 2-AST solenoid valve; 3-ASP throttling assembly, 31-throttle hole; 4-OPC solenoid valve; 5-plate type stop valve, 51-upper plate, 52-middle plate, 53-lower plate; 6-pressure measuring joint; 7-valve plate; 8-valve stem. DETAILED DESCRIPTION

[0027] It should be understood that the embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the application.

[0028] The technical solution of the present invention is further specifically described below through examples.

[0029] A novel emergency trip device comprises four sets of AST solenoid valves 2 connected in series and parallel, two sets of OPC solenoid valves 4, and a pressure measuring assembly; the device is installed in the high-pressure fire-resistant oil EH system of the steam turbine, receives the trip command of the ETS system, and realizes the emergency trip of the steam turbine to protect the safety of the steam turbine.

[0030] Four sets of AST solenoid valves 2 are secured to the top of the hydraulic manifold 1 via plate-type shutoff valves 5. The OPC solenoid valve 4 is also secured directly to the top of the hydraulic manifold 1. An ASP throttling assembly 3 is also secured to the top of the hydraulic manifold 1 via plate-type shutoff valves 5. The hydraulic manifold 1 is constructed of stainless steel, or alternatively carbon steel, and its surface is treated with zinc passivation or other corrosion protection. Inside the hydraulic manifold 1, the four AST solenoid valves 2 are arranged in series and parallel via hydraulic piping channels to facilitate online testing of the AST solenoid valves' functionality.

[0031] Each plate-type stop valve 5 comprises an upper plate 51, a middle plate 52, and a lower plate 53. Each of the five sets of plate-type stop valves 5 is equipped with a sliding valve on its side. The sliding valve comprises a valve plate 7, a valve stem 8, and an indicator plate. The indicator plate is attached to the side of the middle plate 52 of the plate-type stop valve 5. The valve plate 7 is connected to the indicator plate via the valve stem 8. The valve plate 7 and valve stem 8 can move back and forth to control the opening and closing of the valve port. Turning the valve stem 8 and valve plate 7 activates the closing and opening of the solenoid valve. The indicator plate rotates synchronously with the movement of the valve plate 7 and valve stem 8. A limit screw is provided on the lower plate 53 to limit the indicator plate's rotational position, preventing the valve stem 8 from being excessively stretched and damaged or malfunctioning.

[0032] The AST solenoid valve 2 and ASP throttle assembly 3 are equipped with pressure-testing connections; they are generally not connected to pressure gauges during normal operation. When the orifice 31 of the AST solenoid valve 2 and ASP throttle assembly 3 needs to be inspected, a pressure gauge can be connected to monitor the correctness and reliability of the on-off operation of the plate-type stop valve 5. A high pressure reading on the pressure gauge indicates that the plate-type stop valve 5 is effectively open; a zero pressure reading indicates that the plate-type stop valve 5 is effectively closed. Closing the plate-type stop valve 5 corresponding to the orifice 31 allows for online inspection or replacement of both orifices 31.

[0033] The AST oil inlet pipe is divided into three branches. The first branch is equipped with an ASP throttling assembly 3, including throttling holes K1 and K2. The second branch is equipped with AST solenoid valves AST-3 and AST solenoid valves AST-4, and the third branch is equipped with AST solenoid valves AST-3 and AST solenoid valves AST-4. In addition, AST solenoid valves AST-1 and AST solenoid valves AST-4 are connected in series; AST solenoid valves AST-2 and AST solenoid valves AST-3 are connected in series; AST solenoid valves AST-1 and AST solenoid valves AST-3 are connected in parallel; and AST solenoid valves AST-2 and AST solenoid valves AST-4 are connected in parallel. The emergency shutoff device is connected to the AST safety oil inlet and return ports. The four AST solenoid valves 2 are arranged in series and parallel. Individual actuation of each AST solenoid valve 2 will not cause the emergency shutoff device to malfunction or fail to operate. Therefore, the AST solenoid valves 2 have online testing and detection capabilities.

[0034] A channel is provided between orifices K1 and K2; this channel connects AST solenoid valves AST-1 and AST-2, and also connects AST solenoid valves AST-3 and AST-4. Two sets of ASP pressure switches are located between these channels. These two ASP pressure switches, ASP-1 and ASP-2, indicate the effectiveness and correctness of the AST solenoid valve 2 during test operation. When AST solenoid valves AST-1 and AST-3 operate correctly, ASP pressure switch ASP-1 triggers a high pressure alarm. When AST solenoid valves AST-2 and AST-4 operate correctly, ASP pressure switch ASP-2 triggers a low pressure alarm. If all four AST solenoid valves 2 fail to operate, but one of the ASP pressure switches ASP-1 or ASP-2 triggers an alarm, this indicates a fault in orifice K1 or K2. If ASP pressure switch ASP-1 triggers a high pressure alarm, then orifice K2 is faulty; if ASP pressure switch ASP-2 triggers a low pressure alarm, then orifice K1 is faulty and requires prompt repair. By closing the plate stop valve 5, the throttle hole can be cleaned or replaced online.

[0035] The OPC oil inlet pipe is connected to two sets of OPC solenoid valves 4 respectively; another AST oil inlet pipe is connected to two sets of OPC solenoid valves 4 respectively through a one-way valve. An OPC pressure switch 63 / OPC is set at the input of the OPC oil inlet pipe.

[0036] The HP oil pipeline is divided into two branches. The first branch is connected to AST solenoid valve AST-1 and AST solenoid valve AST-2 through a one-way valve, and the second branch is connected to AST solenoid valve AST-3 and AST solenoid valve AST-4 through a one-way valve.

[0037] Two sets of check valves are installed in hydraulic manifold block 1, effectively separating the hydraulic channels for the AST and OPC safety oils. When OPC solenoid valve 4 actuates, the OPC safety oil drains away, but due to the one-way action, the AST safety oil remains unaffected. When AST solenoid valve 2 actuates, the AST safety oil drains away, but the check valves also rapidly drain the OPC safety oil, rapidly closing all valves and safely shutting down the turbine.

[0038] See also Figure 1 The main functions of the emergency shut-off device of the present invention are: first, it receives the shut-off signal from the turbine ETS, the AST / OPC solenoid valve 4 is actuated, the EH safety oil loses pressure rapidly, and the turbine valve is quickly closed under the action of the spring force to ensure the safety of the turbine. Second, it has an online testing function. In order to ensure that the AST solenoid valve 2 operates correctly and quickly, the AST solenoid valve 2 must be inspected and tested online during normal operation of the unit to prevent it from getting stuck or burning due to long-term inaction. Weekly inspection and testing is a basic requirement for safe power operation. Third, it has an online replacement function. Once a malfunctioning or faulty solenoid valve is found during the test, it must be repaired or replaced immediately to ensure that the four AST solenoid valves 2 are always in normal working condition, and no AST solenoid valve 2 is allowed to be in a faulty state. Fourth, it has a self-correcting function for test conditions.

[0039] The online detection and judgment of AST solenoid valve 2 is based on the output signals of the two ASP pressure switches. The reference pressure of the two ASP pressure switches is determined by matching the two orifices 31. If either orifice 31 fails, the ASP reference pressure will change, and the two ASP pressure switch activation signals will also change. When the ASP reference pressure value changes, the two orifices 31 must be repaired or replaced immediately to correct the ASP reference pressure value at any time.

[0040] The safety oil provided by the emergency shutoff device of the present invention mainly serves to supply the safety valve control oil required by the actuator. Only when the safety oil pressure is established normally can the actuator operate accurately.

Claims

1. A novel emergency shutoff device, characterized in that: The invention comprises four groups of AST solenoid valves (2) connected in series and parallel, two groups of OPC solenoid valves (4), and a pressure measuring assembly; the AST solenoid valves (2) are assembled on the top of the hydraulic integrated block (1) through a plate-type stop valve (5); the OPC solenoid valves (4) are assembled on the top of the hydraulic integrated block (1); the pressure measuring assembly is arranged on the AST solenoid valves (2); the device also comprises an ASP throttling assembly (3); the ASP throttling assembly (3) is assembled on the hydraulic integrated block (1) through a plate-type stop valve (5); a one-way valve is provided at the oil inlet main pipe of the AST solenoid valve and the OPC solenoid valve, and the one-way valve is arranged in the hydraulic integrated block, and the four AST solenoid valves are arranged in series and parallel through a hydraulic pipeline channel inside the hydraulic integrated block: AST solenoid valve AST-1 and AST solenoid valve AST-4 are connected in series; AST solenoid valve AST-2 and AST solenoid valve AST-3 are connected in series; AST solenoid valve AST-1 and AST solenoid valve AST-3 are connected in parallel; AST solenoid valve AST-2 In parallel with AST solenoid valve AST-4; the AST oil inlet pipe is divided into three branches; the first branch is provided with an ASP throttling assembly, the second branch is provided with AST solenoid valve AST-1 and AST solenoid valve AST-2 in sequence, and the third branch is provided with AST solenoid valve AST-3 and AST solenoid valve AST-4 in sequence.

2. The novel emergency shutoff device according to claim 1, characterized in that: The ASP throttling assembly (3) includes a throttling hole K1 and a throttling hole K2; the AST oil inlet pipe is connected to two groups of OPC solenoid valves (4) through a one-way valve; the OPC oil inlet pipe is connected to two groups of OPC solenoid valves (4); the HP oil delivery pipe is divided into two branches, the first branch is connected to the AST solenoid valve (2) AST-1 and the AST solenoid valve (2) AST-3 through a one-way valve, and the second branch is connected to the AST solenoid valve (2) AST-2 and the AST solenoid valve (2) AST-4 through a one-way valve.

3. A novel emergency shutoff device according to claim 2, characterized in that: A channel is provided between the throttle hole K1 and the throttle hole K2; the channel connects the AST solenoid valve (2) AST-1 and the AST solenoid valve (2) AST-2; the channel connects the AST solenoid valve (2) AST-3 and the AST solenoid valve (2) AST-4; and two groups of ASP pressure switches are provided between the channels.

4. A novel emergency shutoff device according to claim 1, characterized in that: A pressure measuring joint (6) is provided on the top of the throttling assembly and the top of the AST solenoid valve (2), respectively.

5. A novel emergency shutoff device according to claim 1, characterized in that: The hydraulic integrated block (1) is provided with internal oil inlet and return channels for AST safety oil, OPC safety oil, and ASP test oil; the hydraulic integrated block (1) is also provided with an external interface.

6. A novel emergency shutoff device according to claim 1, characterized in that: The oil inlet main pipe of the AST solenoid valve (2), the oil inlet main pipe of the OPC solenoid valve (4), and the test oil main pipe of the ASP throttling assembly (3) are provided with pressure switches; the oil inlet main pipe of the AST solenoid valve (2), the oil inlet main pipe of the OPC solenoid valve (4), and the test oil main pipe of the ASP throttling assembly (3) are all provided with pressure gauges; and the oil inlet main pipe of the AST solenoid valve (2) is provided with a pressure transmitter.

7. A novel emergency shutoff device according to claim 1, characterized in that: The plate-type stop valve (5) is connected to a pressure gauge via the output interface of the pressure measuring component, and the pressure gauge includes pressure indication marks for effective opening and closing valve positions.

8. The novel emergency shutoff device according to claim 1, characterized in that: A slide valve is installed on the plate-type stop valve (5); the slide valve comprises a valve plate (7), a valve stem (8) and an indicator plate; the indicator plate is arranged on one side of the stop valve, and the valve plate (7) is fixed to the indicator plate via the valve stem (8).

9. A novel emergency shutoff device according to claim 8, characterized in that: The plate-type stop valve (5) is provided with an open valve position stroke mark, a closed valve position stroke mark and a mechanical limit device.

Images