JP3186491B2 - Method and apparatus for testing mobility of valve stem of steam stop valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable valve stem for testing the valve stem of a hydraulically operated main steam stop valve used for emergency shutoff of steam supplied to a steam turbine during operation of the steam turbine. The present invention relates to a test method and a test apparatus.

[0002]

2. Description of the Related Art A steam supply system of a steam turbine is provided with a steam stop valve for urgently shutting off the supply of steam in accordance with the operation state of the turbine. This steam stop valve
It is used in the open state during normal operation, and is used as the closed state when emergency shutoff is performed.The open state is maintained by applying the hydraulic pressure of high-pressure hydraulic oil, and closed by the built-in spring force by reducing the hydraulic pressure. A single-acting spring-operated valve in a state is generally used. During the operation of the turbine, as described above, the steam stop valve is used in a normally open state and allows high-temperature steam to flow inside, so that deposits may accumulate inside,
Alternatively, a situation occurs in which foreign matter is mixed. If such deposits are deposited or foreign matter is mixed in, the valve stem of the steam stop valve sticks to the valve box. There is a risk that it will not be possible. Therefore, in this type of steam stop valve, a method is adopted in which a valve rod mobility test device is incorporated and tested in order to appropriately confirm the valve rod mobility during operation of the turbine.

FIG. 5 is a cross-sectional view schematically showing a steam stop valve incorporating a conventional valve stem mobility test apparatus. In the figure, a valve rod 1 having a valve body 2 attached to one end is provided with a spring 5.
And is connected to the valve box 3 via. The other end of the valve stem 1 is fixed to a valve piston 7 incorporated in a cylinder 6. When operating pressure is applied to the operating oil working space 10 of the cylinder 6 by the operating hydraulic device 12, the valve piston 7 receives a rightward force in the figure, and moves the valve stem 1 rightward against the extension of the spring 5. As a result, the valve body 2 separates from the valve seat 4 to open the steam stop valve, and the steam flows from the steam inlet 21 to the steam outlet 22. When the oil pressure in the working oil working space 10 of the cylinder 6 of the steam stop valve in the open state is reduced, the valve rod 1 moves leftward in the drawing due to the extension of the spring 5, and the valve body 2 moves to the valve seat 4. The steam stop valve is closed by being pressed.

[0004] In the steam stop valve of this configuration, a back surface of the valve piston 7 (right side in the figure) is used for a valve rod mobility test.
A test piston 8, which is operated by the hydraulic pressure of the test piston action space 11, is disposed in contact with the valve piston 7, and the hydraulic pressure of the hydraulic oil action space 10 is controlled by operating the manual opening / closing valve 14 using the test hydraulic device 13. A method of testing the movability of the valve stem 1 by applying a hydraulic pressure set to a higher pressure to the test piston working space 11 to release the force for moving the valve piston 7 rightward. The stopper 9 limits the movable range of the test piston 8 and limits the movement of the valve stem 1 during the test to a range that does not hinder the holding of the open state of the steam stop valve.

[0005]

As described above, by using the conventional valve rod movable test apparatus, it is possible to test the mobility of the valve rod of the steam stop valve during the operation of the turbine.
Check that the steam stop valve is closed at the time of emergency shutdown.
You can check in advance. However, in the valve rod movable test apparatus of this type, since the pressure applied to the back surface of the valve piston 7 by the test piston 8 is set to a pressure set higher than the operating pressure, the movability of the valve rod 1 is examined. The mobility in a state where a force greater than the extension force of the spring 5 compressed to 1 is applied will be tested. Therefore, even if the valve stem 1 is moved in the test using this test apparatus, the valve stem 1 is reliably moved during the normal operation of the steam stop valve that moves and closes the valve stem 1 only by the tension of the compression spring. The drawback is that it does not guarantee that it can move.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described difficulties, and has as its object to accurately determine whether a valve stem of a steam stop valve can be moved by a force corresponding to a normal closing operation. To provide a mobility test method and a test apparatus therefor.

[0007]

In order to achieve the above-mentioned object, in the present invention, a closed state is achieved by moving a valve stem by a spring force and pressing a valve body incorporated at the tip against a valve seat of a valve box. A steam stop of a steam turbine that is opened by applying operating hydraulic pressure to a cylinder that houses a valve piston connected to the other end of the valve rod and applying a force opposite to the spring force to move the valve rod. In the valve, when the steam stop valve is in an open state, a test oil pressure is applied to a test piston arranged in contact with the valve piston to apply a force in the same direction as a spring force to the valve piston, thereby causing the valve stem to move at the start of movement. A valve rod mobility test method for testing whether the valve rod can move during the closing operation by measuring the test oil pressure will be used.

In order to test whether or not the valve stem can be moved when the steam stop valve shifts to the closed state by the above-described method, the above-mentioned cylinder is provided with a valve piston and a test piston therein, and these two pistons are incorporated therein. A test hydraulic pressurizing means for applying hydraulic pressure to the test hydraulic working space by providing an operating hydraulic working space for the valve piston and a test hydraulic working space for the test piston with two pistons interposed, and a hydraulic pressure for measuring the applied hydraulic pressure A test device provided with a measuring means is used.

Further, the test hydraulic pressure applying means is constituted by a test hydraulic device and a manual valve, and the hydraulic pressure measuring means is constituted by a pressure gauge. Further, the test hydraulic pressure applying means is constituted by a test hydraulic device and an electromagnetic valve, and the oil pressure measuring means is constituted by a pressure transmitter. Furthermore, a test device is configured by adding a valve rod movement detecting means composed of, for example, a limit switch.

[0010]

As described above, if a test oil pressure is applied to the test piston and a force in the same direction as the spring force is applied to the valve piston, the force acting on the valve piston against the spring force is changed from the operating oil pressure to the test oil pressure. Is reduced. Therefore, by measuring the test oil pressure at the start of the movement of the valve stem and subtracting the measured test oil pressure from the operating oil pressure that keeps the valve piston open, the valve stem starts to move when the operating oil pressure is reduced in an emergency Then, the pressure at which the steam stop valve shifts to the closed state can be known. That is, if the test oil pressure at the start of the movement of the valve stem is lower than the operating oil pressure, it is known that the valve stem operates normally in an emergency.

Therefore, the cylinder has a valve piston and a test piston built therein, and a working hydraulic working space for the valve piston and a test working space for the test piston are provided with the two pistons interposed therebetween. If a valve stem movable test device comprising a test oil pressure applying means for applying oil pressure to the test oil pressure working space and an oil pressure measuring means for measuring the applied oil pressure is used, by using the above method, in case of an emergency, It is possible to test whether the valve stem operates normally.

In particular, the test oil pressure is applied by a hydraulic device and a manual valve, and the oil pressure is measured by a pressure gauge. The manual valve is opened to increase the pressure applied to the test hydraulic working space of the test piston, and the test piston moves. By measuring the value of the hydraulic pressure at the time of the operation with a pressure gauge, it is possible to know the test hydraulic pressure at the start of the movement of the valve stem. Therefore, by comparing the test oil pressure at the start of the movement with the operating oil pressure, it is possible to know whether or not the valve stem is movable in an emergency.

If the test oil pressure is applied by a hydraulic device and an electromagnetic valve and the oil pressure is measured by a pressure transmitter, the operation of applying the test oil pressure is automatically performed by the electromagnetic valve, and the applied test oil pressure is applied. Is obtained as an electric signal, so that the test oil pressure is easily and accurately applied and measured. Furthermore, if the movement of the valve stem is detected by the limit switch, the movement of the valve stem is electrically detected, so that the test oil pressure at the start of the movement of the valve stem can be easily and accurately known. . Therefore, by comparing the measured oil pressure with the operating oil pressure, the mobility of the valve stem in an emergency can be accurately known.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a steam stop valve incorporating a valve stem mobility test device according to a first embodiment of the present invention. FIGS. It is sectional drawing which shows typically the steam stop valve which incorporated the valve rod mobility test apparatus of 2nd Example, 3rd Example, and 4th Example.

In these figures, components having the same functions as those of the conventional apparatus of FIG. 5 described above are denoted by the same reference numerals, and redundant description will be omitted. The first embodiment shown in FIG. 1 differs from the conventional apparatus shown in FIG. 5 in that a pressure gauge 16 is incorporated as a hydraulic pressure measuring means for measuring the hydraulic pressure applied to the test piston working space 11. is there. The test hydraulic pressurizing means includes a test hydraulic device 13 and a manual valve 14.
It consists of. In the test device of this configuration,
By operating the manual valve 14 and applying hydraulic pressure to the test piston action space 11 by the test hydraulic device 13, the movement of the valve rod 1 is visually checked, and the indicated value of the pressure gauge 16 at that time is read, and the movement at the start of movement is performed. A method for determining the test oil pressure is adopted. This measured value is applied to the working oil working space 1 by the working hydraulic device 12.
If the operating oil pressure is smaller than 0, the steam stop valve operates normally, and if the operating oil pressure is removed in an emergency, the valve stem 1 moves to the left in the drawing and is closed. .

A feature of the second embodiment shown in FIG. 2 is that the test hydraulic pressurizing means is composed of a test hydraulic device 13, a pressure reducing valve 17, and a manual valve 14, and is provided between the pressure reducing valve 17 and the manual valve 14. The pressure gauge 16 is incorporated as a hydraulic pressure measuring means. In the test apparatus of this configuration, the test oil pressure is set by operating the pressure reducing valve 17 while visually checking the indicated value of the pressure gauge 16, and then the manual valve 14 is opened to apply the test oil pressure to the test piston working space 11. It is visually checked whether or not the rod 1 moves to the left in the drawing, and the above operation is repeated while increasing the set oil pressure until the movement is started, and the test oil pressure at which the valve stem 1 starts moving from the set oil pressure. , And from this value,
As in the first embodiment, a method of determining whether the valve stem 1 of the steam stop valve operates normally is employed.

The feature of the third embodiment shown in FIG. 3 resides in that the test apparatus of the second embodiment employs a valve rod movement detecting means comprising a limit switch 23, which is accompanied by a third embodiment. An electromagnetic valve 19 is used instead of the manual valve 14 in the second embodiment, and an electric test apparatus 20 that operates the electromagnetic valve 19 and detects the operation of the limit switch 23 is used. In the test device of this configuration, after the test oil pressure is set by operating the pressure reducing valve 17, the electromagnetic valve 19 is opened by the electric test device 20, the test oil pressure is applied to the test piston working space 11, and the electric test device 20 limits the test oil pressure. Switch 23
Is detected, the movement of the valve stem 1 is confirmed.
In this method, since the movement of the valve stem 1 is automatically detected, the movement start test oil pressure of the valve stem 1 of the steam stop valve can be easily and accurately obtained, and the mobility of the valve stem 1 can be accurately determined. You can judge.

If the manual valve 14 used in the second embodiment is used instead of the solenoid valve 19 in the third embodiment shown in FIG. 3, manual valve operation is required. 1
Of the steam stop valve is automatically detected.
Needless to say, it is possible to accurately determine the movement start test hydraulic pressure of the valve stem 1 and accurately determine the movability of the valve stem 1.

The feature of the fourth embodiment shown in FIG. 4 is that a test hydraulic pressurizing means comprising a test hydraulic device 13 and a solenoid valve 19, and a hydraulic pressure measuring means comprising a pressure transmitter 18 are used.
Further, a valve rod movement detecting means including a limit switch 23 is used, and an electric test apparatus 20 for electrically detecting and controlling these is incorporated. In the test apparatus having this configuration, the electromagnetic valve 19 is opened by the electric test apparatus 20, and the test oil pressure is applied to the test piston working space 11,
The value of the test oil pressure applied to the test piston working space 11 in response to the signal from the pressure transmitter 18 is detected, and the operation of the limit switch 23 is detected by the electric test device 20 to confirm the movement of the valve stem 1. Becomes In this method, the operation and measurement of the test are all performed automatically and with high accuracy, and the mobility of the valve stem 1 of the steam stop valve can be more accurately determined.

[0020]

As described above, according to the present invention, the valve rod is moved by the spring force, and the valve element incorporated at the tip is pressed against the valve seat of the valve box to close the valve. In the steam stop valve of the steam turbine which is opened by applying the operating oil pressure to the cylinder housing the valve piston connected to the valve and applying a force opposite to the spring force to move the valve rod, the steam stop valve is When in the open state, the test oil pressure is applied to the test piston arranged in contact with the valve piston, a force in the same direction as the spring force is applied to the valve piston, and the test oil pressure at the start of the movement of the valve stem is measured. Since the method of testing whether or not the valve stem can move during the closing operation is used, the measured test hydraulic pressure at the start of movement is compared with the operating oil pressure to know the magnitude, so that the valve stem can be used in an emergency. Normal operation and transition to the closed state Luke mobility test method for valve stem of steam stop valve whether is accurately grasped became can be obtained.

The cylinder has a valve piston and a test piston built therein, and a working hydraulic working space for the valve piston and a test working space for the test piston are provided with the two pistons interposed therebetween. If a valve stem movable test device comprising test oil pressure applying means for applying oil pressure to the test oil pressure working space and oil pressure measuring means for measuring the applied oil pressure is provided, the above method allows the valve stem to be used in an emergency. It is possible to obtain a valve rod mobility test device of a steam stop valve that can accurately grasp whether or not it operates normally.

Further, if the above-mentioned test hydraulic pressurizing means is constituted by a test hydraulic device and a manual valve, and the above-mentioned hydraulic pressure measuring means is constituted by a pressure gauge, the valve rod can be manually operated to move the valve stem. Thus, there is obtained a valve rod movability test apparatus of a type in which the test hydraulic pressure at the start is visually measured.
Further, if the test hydraulic pressure applying means is constituted by a test hydraulic device and an electromagnetic valve, and the oil pressure measuring means is constituted by a pressure transmitter, the operation of applying the test oil pressure and the measurement are automatically performed. If the addition of a valve stem movement detecting means such as a limit switch is added, the movement of the valve stem during the test is automatically detected, so that the valve stem can be easily and accurately detected. The test oil pressure at the start of movement can be known. Therefore, by comparing the measured oil pressure with the operating oil pressure, it is possible to accurately know the mobility of the valve stem in an emergency, which is suitable as a valve stem mobility testing device for a steam stop valve.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a steam stop valve incorporating a valve rod mobility test device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing a steam stop valve incorporating a valve rod mobility test device according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view schematically showing a steam stop valve incorporating a valve rod mobility test device according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically showing a steam stop valve incorporating a valve rod mobility test apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view schematically showing a steam stop valve incorporating a conventional valve stem mobility test device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve stem 2 Valve body 3 Valve box 4 Valve seat 5 Spring 6 Cylinder 7 Valve piston 8 Test piston 10 Hydraulic oil working space 11 Test piston working space 12 Working hydraulic device 13 Test hydraulic device 14 Manual valve 16 Pressure gauge 17 Pressure reducing valve 18 Pressure Transmitter 19 Solenoid Valve 20 Electric Test Equipment 21 Steam Inlet 22 Steam Outlet

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F01D 17/10 F01D 17/26 F01D 25/00 F01D 21/00 F01D 21/20

Claims (6)

(57) [Claims] 1. A cylinder for storing a valve piston connected to the other end of a valve stem, the valve stem being moved by a spring force, and a valve body incorporated at the tip being pressed against a valve seat of a valve box to be closed. In a steam stop valve of a steam turbine which is opened by applying a hydraulic pressure and applying a force opposite to a spring force to move a valve rod, when the steam stop valve is in an open state, the valve piston A test oil pressure is applied to a test piston arranged in contact with the valve piston to apply a force in the same direction as the spring force to the valve piston. A method for testing the mobility of a valve stem of a steam stop valve, which tests whether the valve stem can be moved. 2. The cylinder has a built-in valve piston and the test piston disposed in contact with the valve piston, and an operation hydraulic operation for operating the valve piston with the two pistons interposed therebetween. A test hydraulic pressure applying means for applying a hydraulic pressure to the test hydraulic working space of the test piston, and measuring the applied hydraulic pressure. 2. An oil pressure measuring means, comprising:
A valve stem mobility test apparatus used in the steam stop valve stem mobility test method described above. 3. The steam stop valve according to claim 2, wherein said test hydraulic pressure applying means comprises a test hydraulic device and a manual valve, and said hydraulic pressure measuring means comprises a pressure gauge. Valve stem mobility test equipment. 4. A steam stop valve according to claim 2, wherein said test hydraulic pressure applying means comprises a test hydraulic device and an electromagnetic valve, and said hydraulic pressure measuring means comprises a pressure transmitter. Valve rod mobility testing equipment. 5. An apparatus for testing the mobility of a valve stem of a steam stop valve according to claim 2, further comprising a valve stem movement detecting means. 6. An apparatus according to claim 5, wherein said valve rod movement detecting means comprises a limit switch.