Detection device and method for accurately measuring closing time of steam extraction check valve

Abstract

The invention discloses a detection device and method for accurately measuring the closing time of a steam extraction check valve, belongs to the technical field of valve detection, and aims to solve the problem that the valve closing time of the steam extraction check valve is not accurately measured. The device comprises a fixing support, a suction cup, an electromagnet and a crane, a steam extraction check valve and the fixing support are arranged on a supporting body, a fixed pulley is arranged on the fixing support, a mounting frame is connected with a valve body, an angle sensor, a first travel switch and a second travel switch are mounted on the mounting frame, a pointer shaft is connected with a valve rod, and the angle sensor makes contact with the pointer shaft. When the valve is closed, the swing rod makes contact with the second travel switch, one end of the steel wire rope is connected with the valve clack, the other end of the steel wire rope bypasses the fixed pulley and is connected with the suction cup, the crane is connected with the electromagnet, and the suction cup is attracted to or separated from the electromagnet. Opening and closing positions and time are measured through the timer and the data acquisition device, the assembling and testing method is simple, operation is easy and convenient, safety is high, and measured data are accurate.

Description

Technical Field

[0001] The present invention belongs to the technical field of valve detection, and in particular relates to a detection device and method for accurately measuring the closing time of a steam extraction check valve. Background Art

[0002] The extraction check valve is a non-return valve, generally used in the steam turbine extraction system pipeline to prevent the medium from flowing back into the steam turbine and causing damage to the turbine blades when the steam turbine unit fails. It also prevents the system pipeline from leaking and causing water to enter the steam turbine from the extraction pipeline and cause water hammer accidents, so as to protect the safe operation of the steam turbine.

[0003] To achieve the function of the steam extraction check valve, the rapid closing time of the steam extraction check valve is an important technical requirement of the product design. The steam extraction check valve is equipped with a drive actuator to drive the steam extraction check valve to close quickly. The rapid closing test requires the closing time to be less than or equal to 0.5 seconds. The rapid closing time includes the time T1 from the actuator solenoid valve losing power to the actuator actuation and the time T2 from the valve disc actuation to the valve disc closing. T1 + T2 is the rapid closing time. The valve requires external force to open, and it cannot be affected by external forces other than the actuator when closing. Measuring the rapid closing time of the steam extraction check valve is difficult. The connection between the actuator and the valve stem and the connection between the valve stem and the measuring device must be reasonably designed to open the valve disc and prevent the valve disc from closing when the actuator solenoid valve loses power. Improper test methods will result in inaccurate measurement time and even damage to the valve and test equipment. Summary of the Invention

[0004] The purpose of the present invention is to provide a detection device and method for accurately measuring the closing time of a steam extraction check valve, thereby resolving the problem that the valve disc is easily affected by external forces when detecting the closing time of the steam extraction check valve, resulting in inaccurate time measurement. The technical solutions adopted by the present invention are as follows:

[0005] A detection device for accurately measuring the closing time of a steam extraction check valve, wherein the steam extraction check valve comprises a valve body, a valve disc and a valve stem, wherein a valve seat structure is provided in the valve body, the valve stem is hinged in the valve body, the valve disc is connected to the valve stem, and the valve disc opens and closes the valve seat structure;

[0006] The detection device includes a fixed bracket, a suction cup, an electromagnet and a crane. The steam extraction check valve and the fixed bracket are arranged on a support body. The mounting bracket is connected to the valve body. An angle sensor, a first travel switch and a second travel switch are installed on the mounting bracket. One end of the pointer shaft is connected to one end of the valve stem. The probe of the angle sensor is connected to the other end of the pointer shaft. The actuator is fixed to the valve body. The output end of the actuator is connected to the other end of the valve stem. A rocker rod is sleeved on the pointer shaft. When the valve is opened, the rocker rod contacts the first travel switch. When the valve is closed, the rocker rod contacts the second travel switch. One end of the wire rope penetrates into the valve body and is connected to the valve disc. The other end of the wire rope passes around the fixed pulley and extends upward and is connected to the suction cup. The crane is connected to the electromagnet. The suction cup and the electromagnet are attracted or separated.

[0007] The control box is provided with a main power switch, which is electrically connected to the solenoid valve and electromagnet of the actuator respectively. The control box is provided with a first timer and a second timer, the first timer is electrically connected to the actuator, the second timer is electrically connected to the first travel switch and the second travel switch respectively, and the data acquisition device is electrically connected to the angle sensor.

[0008] Furthermore, a tray is provided on the top of the fixed bracket, and a steel wire rope passes through the tray and is connected to the suction cup. When the suction cup is separated from the electromagnet, the suction cup falls into the tray.

[0009] Furthermore, a vertically arranged long hole group is provided on the fixed bracket, and a flange hole group is provided on the bracket of the fixed pulley, and the flange hole group and the long hole group are connected by fastening bolts.

[0010] Furthermore, a hinge hole is provided on the valve body, and the valve stem is rotatably engaged with the hinge hole. The hinge hole is a through hole, and a flange cover is provided on the side where the valve body is connected to the mounting frame. The flange cover closes one end of the hinge hole. The mounting frame, the flange cover and the valve body are connected in sequence. The pointer shaft passes through the flange cover and is connected to the valve stem. A stuffing box is provided on the flange cover, and a packing seal is provided in the stuffing box. The outer periphery of the pointer shaft is rotatably sealed with the flange cover through the packing seal.

[0011] Furthermore, the packing gland is connected to the flange cover by bolts, and the packing gland presses the packing seal on the bottom surface of the stuffing box.

[0012] Furthermore, a shoulder is provided at one end of the pointer shaft close to the valve stem. The shoulder is located between the flange cover and the valve stem. The end face of the flange cover is connected to the end face of the shoulder via a thrust bearing.

[0013] Furthermore, a convex strip is provided on the end surface of the pointer shaft, and a groove is provided on the end surface of the valve stem, and the convex strip is plug-fitted into the groove.

[0014] Furthermore, one end of the valve stem close to the pointer shaft is rotatably engaged with the hinge hole through a copper sleeve.

[0015] Furthermore, the actuator is a servo motor, a stepper motor, a rotary hydraulic cylinder or a rotary pneumatic cylinder.

[0016] The present invention also provides a detection method for accurately measuring the closing time of a steam extraction check valve, which is implemented based on the above-mentioned detection device for accurately measuring the closing time of a steam extraction check valve and includes the following steps:

[0017] Step 1: When the steam extraction check valve is closed, the angle sensor is adjusted to zero, and the main power switch in the control box is turned on to energize the electromagnet. The electromagnet generates magnetic force to attract the suction cup, controlling the crane hook to lift up, thereby causing the wire rope to pull the valve disc to rotate, and the steam extraction check valve to open. The angle sensor records the valve opening angle of the steam extraction check valve and transmits the measured valve opening angle data to the data acquisition device in real time;

[0018] Step 2: Turn off the main power switch in the control box. The electromagnet loses power and the actuator is powered at the same time. The first timer starts timing. When the output end of the actuator starts, the first timer stops timing and the time is recorded as T1.

[0019] Step 3: The actuator drives the valve stem to rotate, and the swing rod disengages from the second travel switch. At the same time, the second timer starts timing. When the steam extraction check valve closes, the swing rod contacts the first travel switch. At the same time, the second timer stops timing and the time is recorded as T2.

[0020] Step 4: The closing time of the steam extraction check valve is T1+T2, and the data acquisition device automatically calculates the result of T1+T2.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] Use a crane to lift the electromagnet. The suction cup is made of magnetic material. When the electromagnet is energized, it generates magnetic force to attract the suction cup, driving the wire rope to pass over the fixed pulley on the fixed bracket and lift it upward to open the steam extraction check valve. By adjusting the distance between the steam extraction check valve and the fixed bracket, it can be applied to steam extraction check valves of different diameters and different opening angles. When the electromagnet is powered off, it can be separated from the suction cup without delay, without affecting the closing time of the steam extraction check valve. The fixed bracket is equipped with a tray to catch the detached suction cup to ensure safety. The pointer shaft is connected to the valve stem and is connected through a flange cover. The pointer shaft and the thrust bearing are pressed against the valve stem to realize axial and radial positioning. A stuffing box is arranged on the flange cover, and the stuffing seal is pressed against the stuffing box through the stuffing gland, which can prevent the medium of the steam extraction check valve from leaking out and ensure that the valve stem drives the pointer shaft to rotate. After the pointer shaft is connected to the rocker arm, it cooperates with the first stroke switch, the second stroke switch and the angle sensor. The position and time of opening and closing of the steam extraction check valve can be measured through the high-precision first timer, the second timer and the data acquisition device. The assembly and test methods are simple, and the operation is easy, the safety is high, and the measurement data is accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural diagram of the present invention when the pre-test steam extraction check valve is closed;

[0024] Figure 2 This is a schematic diagram of the connection between the pointer shaft and the extraction check valve;

[0025] Figure 3 This is a schematic structural diagram of the steam extraction check valve when it is open during testing of the present invention;

[0026] Figure 4 It is a structural diagram of the pointer shaft.

[0027] In the figure, 1. extraction check valve, 2. valve stem, 3. valve disc, 4. wire rope, 5. fixing bracket, 51. fixed pulley, 52. tray, 6. suction cup, 7. electromagnet, 8. crane, 9. control box, 10. data acquisition device, 11. angle sensor, 12. rocker arm, 13. first travel switch, 14. pointer shaft, 15. packing gland, 16. packing seal, 17. flange cover, 18. thrust bearing, 19. valve body, 20. actuator, 21. support body, 22. valve seat structure, 23. mounting bracket, 24. second travel switch, 25. shaft shoulder, 26. ridge, 27. copper sleeve. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of the present invention more clearly apparent, the present invention is described below using specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely illustrative and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0029] The connections mentioned in the present invention are divided into fixed connections and detachable connections. The fixed connection refers to a non-detachable connection, including but not limited to conventional fixed connection methods such as hem connection, rivet connection, adhesive connection, and welding connection. The detachable connection refers to but not limited to conventional detachable connection methods such as bolt connection, snap connection, pin connection, and hinge connection. When the specific connection method is not clearly specified, it is assumed that at least one connection method can be found among the existing connection methods to achieve the function. Those skilled in the art can choose according to their needs. For example, a welded connection is selected for a fixed connection, and a bolted connection is selected for a detachable connection.

[0030] The present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are provided to explain the present invention, but the present invention is not limited to the following embodiments.

[0031] Example 1: Figure 1-4As shown, a detection device for accurately measuring the closing time of a steam extraction check valve is shown. The steam extraction check valve 1 includes a valve body 19, a valve disc 3, and a valve stem 2. A valve seat structure 22 is provided in the valve body 19. The valve stem 2 is hinged in the valve body 19. The valve disc 3 is connected to the valve stem 2. The valve disc 3 opens and closes the valve seat structure 22.

[0032] The detection device includes a fixed bracket 5, a suction cup 6, an electromagnet 7 and a crane 8. The steam extraction check valve 1 and the fixed bracket 5 are arranged on a support body 21. The mounting bracket 23 is connected to the valve body 19. The angle sensor 11, the first travel switch 13 and the second travel switch 24 are installed on the mounting bracket 23. One end of the pointer shaft 14 is connected to one end of the valve stem 2, and the probe of the angle sensor 11 is connected to the other end of the pointer shaft 14. The actuator 20 is fixed to the valve body 19. The output end of the actuator 20 is connected to the other end of the valve stem 2. The rocker rod 12 is sleeved on the pointer shaft 14. When the valve is opened, the rocker rod 12 contacts the first travel switch 13. When the valve is closed, the rocker rod 12 contacts the second travel switch 24. One end of the wire rope 4 penetrates into the valve body 19 and is connected to the valve disc 3. The other end of the wire rope 4 passes around the fixed pulley 51 and extends upward and is connected to the suction cup 6. The crane 8 is connected to the electromagnet 7. The suction cup 6 and the electromagnet 7 are attracted or separated.

[0033] The control box 9 is provided with a main power switch, which is electrically connected to the solenoid valve and electromagnet 7 of the actuator 20 respectively. The control box 9 is provided with a first timer and a second timer, the first timer is electrically connected to the actuator 20, and the second timer is electrically connected to the first limit switch 13 and the second limit switch 24 respectively. The data acquisition device 10 is electrically connected to the angle sensor 11.

[0034] A tray 52 is provided at the top of the fixed bracket 5, and the wire rope 4 passes through the tray 52 and is connected to the suction cup 6. When the suction cup 6 is separated from the electromagnet 7, the suction cup 6 falls into the tray 52. ​​The tray 52 is used to catch the suction cup 6 that falls off to ensure that the suction cup 6 does not injure the staff and objects.

[0035] The fixed bracket 5 is equipped with a vertically arranged set of slots. The bracket for the fixed pulley 51 is equipped with a set of flange holes, which are connected to the slots by fastening bolts. This connection between the flange and slots allows the fixed pulley 51 to be mounted at an adjustable height on the fixed bracket 5 to accommodate extraction check valves 1 of varying diameters and opening angles. This allows the wire rope 4 to exert force on the valve disc 3 in the opening direction without scratching the valve body 19.

[0036] A hinge hole is provided on the valve body 19, and the valve stem 2 is rotatably engaged with the hinge hole. The hinge hole is a through hole. A flange cover 17 is provided on the side where the valve body 19 is connected to the mounting bracket 23. The flange cover 17 closes one end of the hinge hole. The mounting bracket 23, the flange cover 17 and the valve body 19 are connected in sequence. The pointer shaft 14 is connected to the valve stem 2 through the flange cover 17. A stuffing box is provided on the flange cover 17, and a packing seal 16 is provided in the stuffing box. The outer periphery of the pointer shaft 14 is rotatably sealed with the flange cover 17 through the packing seal 16.

[0037] The packing gland 15 is connected to the flange cover 17 by bolts, and the packing gland 15 presses the packing seal 16 on the bottom surface of the stuffing box.

[0038] A shoulder 25 is provided at one end of the pointer shaft 14 close to the valve stem 2 . The shoulder 25 is located between the flange cover 17 and the valve stem 2 . The end surface of the flange cover 17 is connected to the end surface of the shoulder 25 via a thrust bearing 18 .

[0039] A ridge 26 is provided on the end surface of the pointer shaft 14 , and a groove is provided on the end surface of the valve stem 2 , and the ridge 26 is plug-fitted into the groove.

[0040] One end of the valve stem 2 close to the pointer shaft 14 is rotatably engaged with the hinge hole through a copper sleeve 27 .

[0041] The actuator 20 is a servo motor, a stepper motor, a rotary hydraulic cylinder or a rotary pneumatic cylinder.

[0042] Example 2: Figure 1-4 As shown, a detection method for accurately measuring the closing time of a steam extraction check valve is implemented based on the detection device for accurately measuring the closing time of a steam extraction check valve described in Example 1, and includes the following steps:

[0043] Step 1: When the steam extraction check valve 1 is closed, the angle sensor 11 is adjusted to zero, and the main power switch in the control box 9 is turned on to energize the electromagnet 7. The electromagnet 7 generates magnetic force to attract the suction cup 6, controlling the hook of the crane 8 to lift up, thereby causing the wire rope 4 to pull the valve disc 3 to rotate, and the steam extraction check valve 1 is opened. The angle sensor 11 records the valve opening angle of the steam extraction check valve 1 and transmits the measured valve opening angle data to the data acquisition device 10 in real time;

[0044] Step 2: Turn off the main power switch in the control box 9. The electromagnet 7 loses power and the actuator 20 is powered. The first timer starts timing. When the output end of the actuator 20 starts, the first timer stops timing and the time is recorded as T1.

[0045] Step 3: The actuator 20 drives the valve stem 2 to rotate, and the swing rod 12 disengages from the second travel switch 24. At the same time, the second timer starts timing. When the steam extraction check valve 1 closes, the swing rod 12 contacts the first travel switch. At the same time, the second timer stops timing and the time is recorded as T2.

[0046] Step 4: The closing time of the steam extraction check valve 1 is T1+T2, and the data acquisition device 10 automatically calculates the result of T1+T2.

[0047] The first and second timers can be SAND SD4876 timers, and the data acquisition device 10 can be an Ouidi absolute encoder angle rotation CAN / RS485 magnetic microsensor. The first timer controls its own timing by the on / off signal of actuator 20. The first timer is connected to actuator 20 via wiring. When the output of actuator 20 starts to operate, it generates a signal to start the first timer, and when the output of actuator 20 stops operating, it generates a signal to stop the first timer, thus achieving the timing function. The second timer is connected to the first limit switch 13 and the second limit switch 24 respectively via wiring. When the pendulum 12 disengages from the first limit switch 13, it generates a signal to start the second timer, and when the pendulum 12 contacts the second limit switch 24, it generates a signal to stop the second timer, thus achieving the timing function. For the data acquisition device 10, please refer to the Taobao link above. It is equipped with an angle sensor and is used to record the angle change value and time of the angle sensor.

[0048] Use crane 8 to lift electromagnet 7. Suction cup 6 is made of magnetic material. When electromagnet 7 is energized, magnetic force is generated to attract suction cup 6, driving wire rope 4 to bypass fixed pulley 51 on fixed bracket 5 and lift upward, so that extraction check valve 1 is opened. By adjusting the distance between extraction check valve 1 and fixed bracket 5, it can be applied to extraction check valves of different calibers and different opening angles. Electromagnet 7 can be separated from suction cup 6 without delay when power is turned off, without affecting the closing time of extraction check valve 1. Fixed bracket 5 is provided with tray 52, which can catch the falling suction cup 6 to ensure safety. Pointer shaft 14 is connected with valve stem 2 and is connected with flange cover 17 and check valve 1 through stop valve 1. The thrust bearing 18 presses the pointer shaft 14 and the valve stem 2 to achieve axial and radial positioning. A stuffing box is set on the flange cover 17, and the stuffing seal 16 is pressed by the stuffing gland 17, which not only prevents the medium of the steam extraction check valve 1 from leaking out, but also ensures that the valve stem 2 drives the pointer shaft 14 to rotate; the pointer shaft 14 is connected to the rocker arm 12 and then cooperates with the first travel switch 13, the second travel switch 24 and the angle sensor 11. The position and time of opening and closing of the steam extraction check valve 1 can be measured by the high-precision first timer, the second timer and the data acquisition device 10. The assembly and test methods are simple, and the operation is easy, the safety is high, and the measurement data is accurate.

[0049] The above embodiments are merely illustrative of the present invention and do not limit its scope of protection. Those skilled in the art may make partial changes thereto, which are within the scope of protection of the present invention as long as they do not exceed the spirit of the present invention.

Claims

1. A detection device for accurately measuring the closing time of a steam extraction check valve, the steam extraction check valve (1) comprising a valve body (19), a valve flap (3) and a valve stem (2), the valve body (19) being provided with a valve seat structure (22), the valve stem (2) being hinged in the valve body (19), the valve flap (3) being connected to the valve stem (2), and the valve flap (3) opening and closing the valve seat structure (22); Features: The detection device comprises a fixed bracket (5), a suction cup (6), an electromagnet (7) and a crane (8); the steam extraction check valve (1) and the fixed bracket (5) are arranged on a support body (21); the mounting bracket (23) is connected to the valve body (19); an angle sensor (11), a first travel switch (13) and a second travel switch (24) are installed on the mounting bracket (23); one end of the pointer shaft (14) is connected to one end of the valve stem (2); the probe of the angle sensor (11) is connected to the other end of the pointer shaft (14); an actuator (20) is fixed to the valve body (19); ), the output end of the actuator (20) is connected to the other end of the valve stem (2), a swing rod (12) is sleeved on the pointer shaft (14), when the valve is opened, the swing rod (12) contacts the first travel switch (13), when the valve is closed, the swing rod (12) contacts the second travel switch (24), one end of the wire rope (4) penetrates into the valve body (19) and is connected to the valve disc (3), the other end of the wire rope (4) bypasses the fixed pulley (51) and extends upward, and is connected to the suction cup (6), the crane (8) is connected to the electromagnet (7), and the suction cup (6) and the electromagnet (7) are attracted to or separated from each other; A main power switch is provided in the control box (9), and the main power switch is electrically connected to the solenoid valve and the electromagnet (7) of the actuator (20) respectively. A first timer and a second timer are provided in the control box (9), and the first timer is electrically connected to the actuator (20), and the second timer is electrically connected to the first travel switch (13) and the second travel switch (24) respectively. The data acquisition device (10) is electrically connected to the angle sensor (11).

2. A detection device for accurately measuring the closing time of a steam extraction check valve according to claim 1, characterized in that: A tray (52) is provided at the top of the fixed bracket (5), and the steel wire rope (4) passes through the tray (52) and is connected to the suction cup (6). When the suction cup (6) is separated from the electromagnet (7), the suction cup (6) falls into the tray (52).

3. A detection device for accurately measuring the closing time of a steam extraction check valve according to claim 1, characterized in that: A vertically arranged long hole group is provided on the fixed bracket (5), and a flange hole group is provided on the bracket of the fixed pulley (51), and the flange hole group is connected to the long hole group by fastening bolts.

4. A detection device for accurately measuring the closing time of a steam extraction check valve according to claim 1, characterized in that: The valve body (19) is provided with a hinge hole, and the valve stem (2) is rotatably matched with the hinge hole. The hinge hole is a through hole. A flange cover (17) is provided on the side of the valve body (19) connected to the mounting frame (23). The flange cover (17) closes one end of the hinge hole. The mounting frame (23), the flange cover (17) and the valve body (19) are connected in sequence. The pointer shaft (14) passes through the flange cover (17) and is connected to the valve stem (2). A stuffing box is provided on the flange cover (17), and a stuffing seal (16) is provided in the stuffing box. The outer periphery of the pointer shaft (14) is rotatably sealed with the flange cover (17) through the stuffing seal (16).

5. A detection device for accurately measuring the closing time of a steam extraction check valve according to claim 4, characterized in that: The packing gland (15) is connected to the flange cover (17) by bolts, and the packing gland (15) presses the packing seal (16) onto the bottom surface of the stuffing box.

6. A detection device for accurately measuring the closing time of a steam extraction check valve according to claim 5, characterized in that: A shaft shoulder (25) is provided at one end of the pointer shaft (14) close to the valve stem (2). The shaft shoulder (25) is located between the flange cover (17) and the valve stem (2). The end surface of the flange cover (17) and the end surface of the shaft shoulder (25) are connected via a thrust bearing (18).

7. A detection device for accurately measuring the closing time of a steam extraction check valve according to claim 6, characterized in that: A convex strip (26) is provided on the end surface of the pointer shaft (14), and a concave strip is provided on the end surface of the valve stem (2), wherein the convex strip (26) is plug-fitted with the concave strip.

8. A detection device for accurately measuring the closing time of a steam extraction check valve according to claim 4, characterized in that: One end of the valve stem (2) close to the pointer shaft (14) is rotatably matched with the hinge hole through a copper sleeve (27).

9. A detection device for accurately measuring the closing time of a steam extraction check valve according to any one of claims 1 to 8, characterized in that: The actuator (20) is a servo motor, a stepper motor, a rotary hydraulic cylinder or a rotary air cylinder.

10. A detection method for accurately measuring the closing time of a steam extraction check valve, implemented by relying on a detection device for accurately measuring the closing time of a steam extraction check valve according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: When the steam extraction check valve (1) is closed, the angle sensor (11) is adjusted to zero, and the main power switch in the control box (9) is turned on to energize the electromagnet (7), so that the electromagnet (7) generates magnetic force to attract the suction cup (6), and controls the hook of the crane (8) to lift up, thereby causing the wire rope (4) to pull the valve disc (3) to rotate, and the steam extraction check valve (1) is opened. The angle sensor (11) records the valve opening angle of the steam extraction check valve (1), and transmits the measured valve opening angle data to the data acquisition device (10) in real time; Step 2: Turn off the main power switch in the control box (9), the electromagnet (7) loses power and the actuator (20) gains power, the first timer starts timing, and when the output end of the actuator (20) starts timing, the first timer stops timing and the time is recorded as T1; Step 3: The actuator (20) drives the valve stem (2) to rotate, and the swing rod (12) is disengaged from the second travel switch (24). At the same time, the second timer starts timing. When the steam extraction check valve (1) is closed, the swing rod (12) contacts the first travel switch. At the same time, the second timer stops timing and the time is recorded as T2. Step 4: The closing time of the steam extraction check valve (1) is T1+T2, and the data acquisition device (10) automatically calculates the result of T1+T2.

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