JP5941388B2 - Emergency control device and master trip valve - Google Patents

Description

  Embodiments described herein relate generally to an emergency control device and a master trip valve.

  FIG. 10 is a schematic diagram showing the configuration of a conventional emergency control device. The emergency control device of FIG. 10 is a device that controls the flow of control oil for the turbine control device in an emergency. Examples of turbines include gas turbines, steam turbines, combined cycle turbines, and the like.

  The emergency control device of FIG. 10 includes a first trip device 1, a second trip device 2, and hydraulic pressure generators 7, 8, 9, and is disposed upstream of all the control devices 10. The first trip device 1 has a first master trip valve 3 that controls the flow of control oil in the uppermost stream and a first lockout valve 4 that controls the flow of control oil downstream of the first master trip valve 3. doing. The second trip device 2 also includes a second master trip valve 5 that controls the flow of control oil downstream of the first lockout valve 4 and a second master trip valve 5 that controls the flow of control oil downstream of the second master trip valve 5. 2 lockout valve 6.

  The emergency control device of FIG. 10 further includes a first oil supply line 31 connecting the output port 17 of the first master trip valve 3 and the input port 18 of the first lockout valve 4, and the output of the first lockout valve 4. A second oil supply line 32 connecting the port 19 and the input port 26 of the second master trip valve 5, a second oil supply line 32 connecting the output port 27 of the second master trip valve 5 and the input port 28 of the second lockout valve 6. 3 oil supply lines 33. The emergency control device of FIG. 10 further includes a bypass oil supply line 34 that branches from the first oil supply line 31 and is connected to the bypass oil supply port 30 of the second lockout valve 6. Reference numeral 16 indicates an input port of the first master trip valve 3, and reference numeral 29 indicates an output port of the second lockout valve 6.

  Here, the structure of the 1st master trip valve 3, the 1st lockout valve 4, the 2nd master trip valve 5, and the 2nd lockout valve 6 is demonstrated in detail.

  The first master trip valve 3 includes two electromagnetic valves 11 and 12 and one spool valve 13, and the second master trip valve 5 has the same configuration. Further, the first lockout valve 4 includes one electromagnetic valve 14 and one spool valve 15, and the second lockout valve 6 has the same configuration as this. Reference numerals 11a, 12a, and 14a denote spool valves that constitute the electromagnetic valves 11, 12, and 14, respectively.

  The control oil is drained by an emergency control device disposed upstream of all the control devices 10 in an emergency. Thereby, all the control apparatuses 10 lose a control mechanism, and a turbine will stop. The emergency control device includes two solenoid valves 11 and 12 and one spool valve 13 as one combination, and two sets thereof (the other set includes two solenoid valves 21 and 22 and one spool valve 23). And it has the structure which prevents malfunctioning by duplication. These valves 11, 12, 13 are connected to each other by an oil pipe for transferring control oil.

JP-A-6-248907

  In the first master trip valve 3, when the downstream solenoid valve 12 is in the non-excited state, the control oil in the oil pipe between the solenoid valves 11 and 12 is discharged, and the oil pipe is empty (that is, filled with air). State). When the downstream solenoid valve 12 is re-excited, it is necessary to supply control oil again into the oil pipe. However, in the conventional emergency control device, since the above-described air exists in the oil pipe, there is a problem that the hydraulic pressure is instantaneously reduced when the control oil is supplied into the oil pipe. The same applies to the second master trip valve 5.

  Therefore, the present invention supplies control oil into the oil pipe between the solenoid valves when the solenoid valve other than the most upstream solenoid valve among the plurality of solenoid valves of the master trip valve is re-excited after being de-energized. It is an object of the present invention to provide an emergency control device and a master trip valve that can suppress an instantaneous drop in hydraulic pressure.

  An emergency control device according to an embodiment is an emergency control device that controls the flow of control oil for a turbine control device in an emergency, and the first master trip valve that controls the flow of control oil; A first trip device having a first lockout valve for controlling the flow of the control oil downstream of the first master trip valve; and a second master for controlling the flow of the control oil downstream of the first lockout valve. A second trip device having a trip valve and a second lockout valve for controlling the flow of the control oil downstream of the second master trip valve. Further, each of the first and second master trip valves includes a plurality of solenoid valves and an input port for inputting the control oil. Further, each of the first and second master trip valves includes a first oil pipe for transferring the control oil from the input port to the electromagnetic valve, and a second oil pipe for transferring the control oil between the electromagnetic valves. With. Further, each of the first and second master trip valves includes a bypass pipe that transfers the control oil flowing in the first oil pipe to the second oil pipe, bypassing the electromagnetic valve.

It is the schematic which shows the structure of the emergency control apparatus of 1st Embodiment. It is the schematic which shows the structure of the 1st master trip valve of 1st Embodiment. It is the schematic which shows the structure of the 1st master trip valve of 2nd Embodiment. It is the schematic which shows the structure of the 1st master trip valve of the modification of 2nd Embodiment. It is the schematic which shows the structure of the emergency control apparatus of 3rd Embodiment. It is the schematic which shows the structure of the emergency control apparatus of 4th Embodiment. It is the schematic which shows operation | movement of the 1st master trip valve of 5th Embodiment. It is the schematic which shows the structure of the 1st master trip valve of 6th Embodiment. It is the schematic which shows the structure of the 1st master trip valve of the modification of 6th Embodiment. It is the schematic which shows the structure of the conventional emergency control apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings referred to in this specification, parts having the same configuration are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
FIG. 1 is a schematic diagram illustrating the configuration of the emergency control device according to the first embodiment. Hereinafter, although the structure of the 1st master trip valve 3 of this embodiment is explained, the 2nd master trip valve 5 of this embodiment also has the same composition as this, and the following explanation is the 2nd master trip valve. The same applies to 5. The same applies to the second to sixth embodiments described later.

  The first master trip valve 3 outputs a plurality (two in this case) of electromagnetic valves 11 and 12, one spool valve 13, a plurality of input ports 16 for inputting control oil, and a control oil. And a plurality of output ports 17. The electromagnetic valves 11 and 12 are provided with spool valves 11a and 12a, respectively. The electromagnetic valves 11 and 12 of the present embodiment are, for example, constantly excited electromagnetic valves.

  In the emergency control device of FIG. 1, a hydraulic circuit is configured in which the spool valves 11a and 12a are operated only when the solenoid valves 11 and 12 are simultaneously de-energized. In the emergency control device of FIG. 1, the master trip valves 3 and 5 are duplicated, and the solenoid valves 11 and 12 of the first master trip valve 3 and the solenoid valves 21 and 22 of the second master trip valve 5 are either The structure is also doubled to prevent malfunction of the emergency control device. In the emergency control device of FIG. 1, while at least one of the first and second master trip valves 3 and 5 is operating, pressure oil (control) is supplied from the output port 29 of the second lockout valve 6 to the control device 10. Oil).

  FIG. 2 is a schematic diagram showing the configuration of the first master trip valve 3 of the first embodiment.

  In addition to the above-described components, the first master trip valve 3 includes a main control oil pipe 41 that supplies control oil from the input port 16 to the electromagnetic valve 11, and an electromagnetic valve that supplies control oil from the electromagnetic valve 11 to the electromagnetic valve 12. An inter-oil pipe 42 and a drain pipe 43 that discharges control oil from the solenoid valves 11 and 12 to the output port 17 are provided. The main control oil pipe 41, the solenoid valve oil pipe 42, and the drain pipe 43 are examples of the first to third oil pipes of the present disclosure, respectively. As understood from the above description, the solenoid valve 11 corresponds to an upstream solenoid valve, and the solenoid valve 12 corresponds to a downstream solenoid valve.

(1) Details of Bypass Pipe 44 Next, the bypass pipe 44 of FIG. 2 will be described in detail.

  The first master trip valve 3 further includes a bypass pipe 44 that always supplies the control oil flowing in the main control oil pipe 41 to the electromagnetic valve oil pipe 42 by bypassing the solenoid valve 11.

  In the first master trip valve 3, when the downstream solenoid valve 12 is in a non-excited state in an actual operation test or the like, the control oil in the solenoid valve oil pipe 42 is discharged and the solenoid valve oil pipe 42 is empty ( That is, it is a state filled with air. When the downstream solenoid valve 12 is re-excited, the control oil needs to be supplied again into the oil valve 42 between the solenoid valves. At this time, in this embodiment, since the control oil can be supplied from the bypass pipe 44 to the oil valve 42 between the solenoid valves, an instantaneous decrease in the hydraulic pressure when the control oil is supplied into the oil pipe 42 between the solenoid valves is suppressed. Can do. Therefore, according to the present embodiment, it is possible to suppress an instantaneous decrease in the control hydraulic pressure or the emergency hydraulic pressure when the upstream solenoid valve 11 is brought into a non-excited state.

  In addition, it is desirable to provide the connection location between the solenoid valve oil pipe 42 and the bypass pipe 44 as close to the solenoid valve 11 as possible on the upstream side. The reason is that the portion of the solenoid valve oil pipe 42 to which the control oil is supplied from the bypass pipe 44 becomes longer, and the solenoid valve oil pipe 42 can be filled with the control oil in a shorter time. is there.

  In addition, the cross-sectional area of the bypass pipe 44 is desirably set smaller than the cross-sectional area of the main control oil pipe 41. The reason is that the flow of control oil in the main control oil pipe 41, which is the original flow of control oil, is not disturbed. In the present embodiment, the sectional area of the bypass pipe 44 is set to ½ or less (for example, about 1/10) of the sectional area of the main control oil pipe 41.

(2) Details of Vent Pipe 45 Next, the vent pipe 45 of FIG. 2 will be described in detail.

  The first master trip valve 3 further includes a vent pipe 45 that discharges the control oil flowing in the solenoid valve oil pipe 42 to the drain pipe 43 by bypassing the solenoid valve 12. Thereby, it becomes possible to always flow control oil from the solenoid valve oil pipe 42 to the drain pipe 43, and this flow makes it possible to remove air remaining in the solenoid valve oil pipe 42. According to the present embodiment, the air in the solenoid valve oil pipe 42 is evacuated, and the solenoid valve oil pipe 42 is filled with the control oil, thereby bringing the upstream solenoid valve 11 into a non-excited state. It is possible to further suppress the instantaneous decrease in the control hydraulic pressure and emergency hydraulic pressure.

  In addition, it is desirable to provide the connection location of the solenoid valve oil pipe 42 and the vent pipe 45 at a point as close to the solenoid valve 12 as possible on the downstream side. The reason is that the length of the portion of the solenoid valve oil pipe 42 through which the air escapes to the vent pipe 45 becomes longer, and the solenoid valve oil pipe 42 can be filled with the control oil in a shorter time.

  Moreover, it is desirable that the cross-sectional area of the vent pipe 45 be set smaller than the cross-sectional area of the electromagnetic valve oil pipe 42. The reason is to prevent the flow of control oil in the solenoid valve oil pipe 42 that is the original flow of control oil from being hindered. In the present embodiment, the cross-sectional area of the vent pipe 45 is set to ½ or less (for example, about 1/10) of the cross-sectional area of the electromagnetic valve oil pipe 42.

(3) Effects of First Embodiment Finally, effects of the first embodiment will be described.

  As described above, in the present embodiment, the bypass pipe 44 is provided between the main control oil pipe 41 and the solenoid valve oil pipe 42. Therefore, according to this embodiment, when the solenoid valves 12 other than the most upstream of the plurality of solenoid valves 11 and 12 of the master trip valve 3 are re-excited after being de-energized, the oil pipe between the solenoid valves It is possible to suppress a momentary decrease in hydraulic pressure when supplying control oil into 42.

  Further, in the present embodiment, a vent pipe 45 is provided between the solenoid valve oil pipe 42 and the drain pipe 43. Therefore, according to the present embodiment, the air staying in the electromagnetic valve oil pipe 42 can be extracted to the drain pipe 43.

(Second Embodiment)
FIG. 3 is a schematic diagram showing the configuration of the first master trip valve 3 of the second embodiment.

  The first master trip valve 3 in FIG. 3 includes an oil amount adjustment valve 61 for adjusting the amount of control oil flowing through the bypass pipe 44. The oil amount adjustment valve 61 is an example of the adjustment mechanism of the present disclosure.

  According to the present embodiment, when control oil does not need to flow through the bypass pipe 44, by reducing the opening of the oil amount adjustment valve 61, most or all of the control oil flowing through the main control oil pipe 41 is inherently reduced. It is possible to flow to the path of. For example, when both of the solenoid valves 11 and 12 are in the non-excited state, the control device 10 can control most or all of the control oil flowing through the main control oil pipe 41 by lowering the opening of the oil amount adjustment valve 61. It is possible to return to the hydraulic pressure generator 8 without supplying it.

  Therefore, according to the present embodiment, when the emergency control device is actually operated on site, the operation of the emergency control device can be adjusted in a timely manner so that the steam turbine is safely stopped in an emergency. This not only makes it possible to confirm that the function as an emergency control device is sufficiently satisfied, but also adjusts the operation of the emergency control device in accordance with the content of the thickener contained in the control oil. This makes it possible to freely select the type of control oil.

  FIG. 4 is a schematic diagram illustrating a configuration of a first master trip valve 3 according to a modification of the second embodiment.

  The first master trip valve 3 of FIG. 4 includes an orifice block 63 having an orifice 62 instead of the oil amount adjusting valve 61.

  The orifice block 63 includes a part of the bypass pipe 44 and is configured to be detachable from the first master trip valve 3. The orifice 62 is a mechanism for adjusting the amount of control oil flowing through the bypass pipe 44 in the orifice block 63 by changing its diameter. The orifice 62 is an example of an adjustment mechanism, and the orifice block 63 is an example of a component including the adjustment mechanism. According to this modification, it is possible to quickly replace the orifice 62 to be used without disassembling the emergency control device.

  As described above, according to the present embodiment, by providing an adjustment mechanism that adjusts the amount of control oil flowing through the bypass pipe 44, it is possible to determine how much control oil flows through the bypass pipe 44 as necessary. It becomes possible to adjust.

(Third embodiment)
FIG. 5 is a schematic diagram showing the configuration of the emergency control device of the third embodiment.

  The first master trip valve 3 in FIG. 5 is configured to be used in a state where the downstream solenoid valve 12 is at a higher position than the upstream solenoid valve 11. Such a configuration can be realized, for example, by designing the device so that the electromagnetic valve 11 is located below the device and the electromagnetic valve 12 is located above the device when designing the emergency control device.

  In the first master trip valve 3, when the solenoid valve 12 on the downstream side is brought into a non-excited state in an actual operation test or the like, the pressure of the control oil in the solenoid valve oil pipe 42 decreases. However, in this embodiment, since the downstream solenoid valve 12 is located higher than the upstream solenoid valve 11, it is possible to prevent the control oil in the oil valve 42 between the solenoid valves from dropping due to the influence of gravity. it can.

  Therefore, in this embodiment, it can prevent that air mixes in the oil pipe 42 between solenoid valves. Therefore, when the downstream solenoid valve 12 is then returned to the excited state and only the upstream solenoid valve 11 is in the non-excited state, the amount of control oil supplied from the main control oil pipe 41 is mixed with air. The amount can be smaller than if it is. Therefore, according to the present embodiment, it is possible to reduce fluctuations in the control hydraulic pressure and the emergency hydraulic pressure.

  As described above, in the present embodiment, the master trip valve 3 is configured to be used in a state where the downstream solenoid valve 12 is higher than the upstream solenoid valve 11. Therefore, according to this embodiment, it is possible to suppress the control oil in the solenoid valve oil pipe 42 from dropping due to the influence of gravity.

(Fourth embodiment)
FIG. 6 is a schematic diagram showing the configuration of the emergency control device of the fourth embodiment.

  FIG. 6 shows three parts 71, 72, 73 constituting the emergency control device, and a part 74 to which the emergency control device is attached.

  The component 71 includes the first and second lockout valves 4 and 6 and the like, and corresponds to the manifold body. The component 72 includes the first master trip valve 3, and the component 73 includes the second master trip valve 5. The parts 72 and 73 are configured to be detachable from the part 71.

  In FIG. 6, the assembly of the first master trip valve 3, the first lockout valve 4, the second master trip valve 5, and the second lockout valve 6 has already been completed in the form of parts 71-73, The assembly of the emergency control device is completed by attaching the parts 72 and 73 to the part 71.

  In this embodiment, it becomes possible to skip the assembly process of the emergency control device at the power plant site by transporting the emergency control device in a state where the assembly of the parts 71 to 73 is completed. Therefore, it is not necessary to temporarily place components such as a solenoid valve and an oil pipe constituting the emergency control device in the power plant site for assembly, and it is possible to save space on the power plant site. In addition, it is possible to reduce the risk of reverse assembly and assembly errors due to local assembly.

  Further, in this embodiment, since the foreign matter in the emergency control device can be removed in a well-organized environment in the assembly plant, the emergency control device must be transported to the power plant site after sufficiently flushing. Is possible. Therefore, the flushing of the emergency control device can be bypassed during the control system flushing process at the power plant site. As a result, it is possible to perform flushing of the control system even when the emergency control device has not arrived at the power plant site, and it is possible to shorten the control system flushing process period as a whole.

(Fifth embodiment)
FIG. 7 is a schematic view showing the operation of the first master trip valve 3 of the fifth embodiment.

  FIG. 7A shows the first master trip valve 3 in a trip state, and FIG. 7C shows the first master trip valve 3 in a reset state. FIG. 7 (b) shows the first master trip valve 3 after FIG. 7 (a), and FIG. 7 (d) shows the first master trip valve 3 after FIG. 7 (c).

  In this embodiment, when changing from the trip state to the reset state, the solenoid valves 11 and 12 are provided with a time difference so that the upstream solenoid valve 11 is in the excited state after the downstream solenoid valve 12 is in the excited state. To work in order. FIG. 7B shows a state in which the downstream solenoid valve 12 is in an excited state, and FIG. 7D shows a state in which the upstream solenoid valve 11 is in an excited state thereafter. .

  Therefore, in this embodiment, after exciting the solenoid valve 12 on the downstream side, the control oil is filled in the oil pipe 42 between the solenoid valves, and then the solenoid valve 11 on the upstream side is excited in the solenoid valve oil pipe 42. It is possible to shift to the reset state while suppressing the occurrence of air accumulation. Therefore, according to the present embodiment, it is possible to reduce fluctuations in the control hydraulic pressure and the emergency hydraulic pressure immediately after shifting to the reset state.

(Sixth embodiment)
FIG. 8 is a schematic diagram showing the configuration of the first master trip valve 3 of the sixth embodiment.

  The first master trip valve 3 in FIG. 8 includes a U seal 81 provided on the downstream side of the most downstream solenoid valve 12. Specifically, the U seal 81 is disposed between the outlet port 17 of the first master trip valve 3 and the hydraulic pressure generator 7. Thereby, when the most downstream solenoid valve 12 is in a non-excited state, it is possible to suppress the falling of control oil existing between the solenoid valves 11 and 12. In addition, the code | symbol 82 shows the U seal provided in the 2nd master trip valve 5 similarly to the 1st master trip valve 3. FIG.

  FIG. 9 is a schematic diagram illustrating a configuration of the first master trip valve 3 according to a modification of the sixth embodiment.

  The first master trip valve 3 in FIG. 9 includes a check valve 83 having a spring instead of the U seal 81. Thereby, when the most downstream solenoid valve 12 is in a non-excited state, it is possible to suppress the falling of control oil existing between the solenoid valves 11 and 12. Moreover, by setting the pressure by the check valve 83 to be equal to or higher than the hydrostatic head pressure generated at the positions of all the solenoid valves 11 and 12, it is possible to suppress discharge of control oil from the emergency control device at the time of trip. It becomes. Reference numeral 84 denotes a check valve provided in the second master trip valve 5 similarly to the first master trip valve 3.

  In the first to sixth embodiments, the configuration of the first master trip valve 3 has been described. However, the second master trip valve 5 also has the same configuration. The second master trip valve 5 of the first embodiment is similar to the first master trip valve 3 in that the electromagnetic valves 21 and 22, the spool valve 23, the input port 26, the output port 27, the main control oil pipe 51, The solenoid valve oil pipe 52, the drain pipe 53, the bypass pipe 54, and the vent pipe 55 are provided. The descriptions of the second to sixth embodiments are also applied to the second master trip valve 5.

  In addition, the first master trip valve 3 of the first to sixth embodiments includes the two electromagnetic valves 11 and 12, but may include three or more electromagnetic valves. Similarly, the second master trip valve 5 of the first to sixth embodiments includes the two electromagnetic valves 21 and 22, but may include three or more electromagnetic valves.

  The first to sixth embodiments have been described above. However, these embodiments are presented as examples, and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms. Moreover, various modifications can be obtained by making various omissions, substitutions, and changes to these embodiments without departing from the scope of the invention. These forms and modifications are included in the scope and gist of the invention, and these forms and modifications are included in the claims and the scope equivalent thereto.

1: first trip device, 2: second trip device,
3: First master trip valve, 4: First lockout valve,
5: Second master trip valve, 6: Second lockout valve,
7, 8, 9: oil pressure generating device, 10: control device,
11, 12, 14: Solenoid valve, 11a, 12a, 13, 14a, 15: Spool valve,
16, 18: input port, 17, 19: output port,
21, 22, 24: Solenoid valve, 21a, 22a, 23, 24a, 25: Spool valve,
26, 28: input port, 27, 29: output port, 30: bypass oiling port,
31: 1st oil supply line, 32: 2nd oil supply line, 33: 3rd oil supply line,
34: Bypass oil supply line,
41, 51: main control oil pipe, 42, 52: solenoid valve oil pipe, 43, 53: drain pipe,
44, 54: Bypass pipe, 45, 55: Vent pipe,
61: Oil amount adjusting valve, 62: Orifice, 63: Orifice block,
71, 72, 73, 74: parts, 81, 82: U seal, 83, 84: check valve

Claims (10)

An emergency control device for controlling the flow of control oil for a turbine control device in an emergency,
A first trip device having a first master trip valve for controlling the flow of the control oil, and a first lockout valve for controlling the flow of the control oil downstream of the first master trip valve;
A second master trip valve that controls the flow of the control oil downstream of the first lockout valve; and a second lockout valve that controls the flow of the control oil downstream of the second master trip valve. 2 trip devices,
Each of the first and second master trip valves is
A plurality of solenoid valves;
An input port for inputting the control oil;
A first oil pipe for transferring the control oil from the input port to the solenoid valve;
A second oil pipe for transferring the control oil between the solenoid valves;
A bypass pipe for transferring the control oil flowing in the first oil pipe to the second oil pipe by bypassing the solenoid valve;
An emergency control device comprising: Each of the first and second master trip valves further includes
An output port for outputting the control oil;
A third oil pipe for transferring the control oil from the solenoid valve to the output port;
A vent pipe that bypasses the solenoid valve and transfers the control oil flowing in the second oil pipe to the third oil pipe;
The emergency control device according to claim 1.   3. The emergency control device according to claim 1, wherein each of the first and second master trip valves further includes an adjustment mechanism that adjusts an amount of the control oil flowing through the bypass pipe.   The emergency control device according to claim 3, wherein the adjustment mechanism is provided in a part that can be attached to and detached from the first or second master trip valve.   Each of the said 1st and 2nd master trip valve is comprised so that it may be used in the state in which the said solenoid valve of a downstream is in a position higher than the said solenoid valve of an upstream. The emergency control device according to claim 1.   Each of the said 1st and 2nd master trip valve is comprised so that it can attach or detach with respect to the components containing the said 1st and 2nd lockout valve, The one of Claims 1-5. Emergency control device.   2. Each of the first and second master trip valves operates the solenoid valves in order so that the upstream solenoid valve is in an excited state after the downstream solenoid valve is in an excited state. The emergency control device according to any one of 6.   The emergency according to any one of claims 1 to 7, wherein each of the first and second master trip valves further comprises a U-seal or a check valve provided downstream of the most downstream solenoid valve. Control device. further,
A first oiling line connecting the output port of the first master trip valve and the input port of the first lockout valve;
A second oiling line connecting the output port of the first lockout valve and the input port of the second master trip valve;
A third oiling line connecting the output port of the second master trip valve and the input port of the second lockout valve;
The emergency control device according to any one of claims 1 to 8, further comprising: a bypass oil supply line branched from the first oil supply line and connected to a bypass oil supply port of the second lockout valve. A master trip valve for controlling the flow of control oil for a control device of a turbine,
A plurality of solenoid valves;
An input port for inputting the control oil;
A first oil pipe for transferring the control oil from the input port to the solenoid valve;
A second oil pipe for transferring the control oil between the solenoid valves;
A bypass pipe for transferring the control oil flowing in the first oil pipe to the second oil pipe by bypassing the solenoid valve;
Master trip valve with

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