JP3341511B2 - Stem-free test equipment for main steam stop valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a main steam stop valve for confirming during operation of a turbine that a main steam stop valve for shutting off steam supplied to a steam turbine can surely shut off steam in an emergency. Related to a stem-free test apparatus.

[0002]

2. Description of the Related Art A main steam stop valve is used to flow steam into and out of a steam turbine, and it is necessary to surely shut off steam in an emergency such as an accident. However, the operation of the valve stem (also referred to as a stem) of the main steam stop valve during turbine operation may be hindered by an increase in scale or sticking due to foreign matter being caught, and emergency shutoff may not be possible. For this reason, in order to confirm that the main steam stop valve can be shut off urgently, the valve rod of the main steam stop valve is operated during turbine operation, and it is confirmed that the main steam stop valve is securely closed at the time of emergency shutoff. A stem-free test device is provided on the main steam stop valve.

FIG. 5 is a diagram showing the construction of a main steam stop valve provided with this type of stem-free test device and opened and closed by a hydraulic cylinder. The prior art will be described with reference to the drawings. FIG.
, The main steam stop valve 1 has a valve body 2, a valve stem 4 to which the valve body 2 is attached, a piston 3 connected to an end different from the valve body 2, and a valve stem 4 penetrating therethrough. Seat 5 for seating
And a valve casing 7 provided with a steam inlet 6.

The hydraulic cylinder 9 is penetrated by a valve stem 4 connected to the piston 3, and has a piston 3, a test piston 12 having a test piston 10 having a diameter larger than the diameter of the piston 3, and a cylinder surrounding the piston 3. And a cylinder 13 having a side wall composed of a cylindrical body 13b surrounding the test piston 10. Here, the test piston 12 is attached to the test piston 10,
A rod 15 is provided for contacting the rear surface of the piston 3.
An oil supply / discharge pipe 16 for supplying / discharging pressure oil to / from the cylinder 13a of the cylinder 13 is connected to a side wall of the cylinder 13a of the cylinder 13, and a three-way valve 18 is connected to a bottom plate 17 of the cylinder 13.
And an oil supply / discharge pipe 20 for supplying / discharging pressure oil between the test piston 10 and the bottom plate 17 is connected. The three-way valve 18 is connected to an oil supply pipe 21 and an oil discharge pipe 22.

A closing spring 23 is provided between a spring seat 24 provided on the valve stem 4 and an upper plate 25 of the cylinder 13, and when the main steam stop valve 1 is closed, the valve stem is closed by a spring force. Move to With such a configuration, during operation of the turbine,
By switching the three-way valve 18, the piston 3 in the cylinder 13
The pressure oil between the oil and the bottom plate 17 is supplied from the oil supply / discharge pipe 20 to the oil discharge pipe 2.
2 and the pressure oil is discharged from the oil supply / discharge pipe 16 to the cylinder 1
The piston 3 connected to the valve stem 4 moves to the right against the force of the closing spring 23 so that the main steam stop valve 1 is fully opened.

In such a state, the valve stem 4 of the main steam stop valve 1
When the movement of the test piston 12 is checked, the three-way valve 18 is switched, and the pressure oil is supplied from the oil supply pipe 21 through the oil supply / discharge pipe 20 into the cylinder 13 on the rear side of the test piston 10 of the test piston 12. Move the piston 12 for
The piston 3 is moved in the closing direction of the valve stem 4 via the rod 15. The stroke of the valve stem 4 at this time is a stroke s until the test piston 10 comes into contact with the step of the connecting portion between the cylinders 13a and 13b of the cylinder 13.

When the main steam stop valve 1 is fully opened after the valve rod 4 is moved in the closing direction, the three-way valve 18 is switched to supply pressure oil between the test piston 10 and the bottom plate 17. By discharging from the oil discharge pipe 22 via the discharge pipe 20, the piston 3 returns to the original position, and the main steam stop valve is fully opened. By monitoring the reciprocating motion of the valve stem 4 by the test piston 12 in the stroke s, it is confirmed that the emergency stop of the main steam stop valve is surely performed.

In the above prior art, the closing of the main steam stop valve 1 in an emergency is confirmed by monitoring the reciprocating motion of the valve rod 4 in a stroke s which is a partial stroke. If multiple turbines are installed and one of the multiple main steam stop valves is fully closed, there is no hindrance to the operation of the turbine, the multiple main steam stop valves are opened and closed sequentially to fully open the valve stem. The reciprocation of the entire stroke leading to closure is monitored to ensure that all main steam stop valves are securely closed in an emergency.

[0009]

During the operation of the turbine, a test piston 12 for reciprocating the valve stem 4 of the main steam stop valve is used to check whether the main steam stop valve in the fully opened state can be closed in an emergency. Since it is necessary to provide a stem-free test device provided in the hydraulic cylinder of the main steam stop valve, there is a problem that the structure becomes complicated and the cost increases.

When a plurality of main steam stop valves are installed in the steam turbine, one main steam stop valve is sequentially opened and closed as described above even if the test piston 12 is not provided. Since it is possible to confirm that the steam stop valve is securely closed in an emergency, the structure of the hydraulic cylinder differs depending on whether the test piston is unnecessary or not depending on the number of installations of the main steam stop valve. There is a problem that it is disadvantageous in standardizing cylinders and series.

It is an object of the present invention to provide a simple structure without a test piston and a reciprocating motion in a partial stroke of a valve stem of a main steam stop valve to a partial opening and a full stroke to a full stroke. An object of the present invention is to provide a stem-free test device for a main steam stop valve, which can confirm that the emergency stop of the main steam stop valve is performed by monitoring.

[0012]

According to the present invention, a valve rod connected to a piston of a hydraulic cylinder is supplied to a cylinder of hydraulic oil via an oil supply / discharge pipe connected to the cylinder. In the stem-free test device of the main steam stop valve, which confirms the movement of the valve stem of the main steam stop valve during turbine operation by reciprocating the steam into and out of the steam turbine by discharging, A flow path for allowing pressure oil supplied to the hydraulic cylinder to flow into the cylinder by switching between excitation and non-excitation, and a flow path for preventing the formation of this flow path and discharging the pressure oil from the cylinder. Solenoid valve for switching between formation and operation, a switch for switching on and off to energize and de-energize an electric circuit connected to the solenoid valve, and the opening of the main steam stop valve is detected by the stroke of the valve rod. The opening detector and this A test opening setter that sets the test opening to be compared with the opening detected by the opening detector to an arbitrary opening from fully closed to fully open, and a test opening setter that detects the opening detected by the opening detector And a comparison operation unit that outputs a signal for switching the changeover switch when the opening is equal to or smaller than the set test opening.

In the stem-free test device for the main steam stop valve, a throttle is provided in a flow path for discharging the pressure oil in the hydraulic cylinder from the switching solenoid valve.

[0014]

In order to open and close the main steam stop valve by reciprocating the piston of the hydraulic cylinder to which the valve stem of the main steam stop valve is connected in the cylinder, an oil supply / discharge pipe is provided for supplying and discharging pressure oil to and from the cylinder. The switching solenoid valve is energized and de-energized by turning off and on an electric circuit connected to the solenoid valve by a changeover switch.
At this time, the switching solenoid valve forms a flow path through which the pressure oil supplied to the hydraulic cylinder flows into the cylinder by either excitation or non-excitation, and the formation of this flow path is prevented, and the pressure oil in the cylinder is prevented. To form a flow path for discharging water to the outside.

Therefore, if the switching solenoid valve is operated by operating the changeover switch to form a flow path into which the hydraulic oil supplied to the hydraulic cylinder flows into the cylinder when it is de-energized, for example, this flow path allows the hydraulic cylinder to flow through the hydraulic cylinder. The supplied pressure oil can be supplied / discharged to / from the cylinder, and the supply / discharge of the pressure oil causes the piston connected to the valve rod to reciprocate and open / close the main steam stop valve. Therefore, by flowing the pressure oil into the cylinder, the piston moves the valve stem connected to the piston in the opening direction, and the main steam stop valve is fully opened.

If the switching switch is switched to excite the switching solenoid valve in the fully opened state of the main steam stop valve, the formation of the flow path is prevented, and the flow path for discharging the pressure oil in the cylinder is formed. The pressure oil in the cylinder flows through this flow path and is discharged to the outside, and the piston moves the valve stem connected to the piston in the closing direction. At this time, the stroke of the valve stem, that is, the opening of the main steam stop valve is detected by the opening detector, and a signal of the detected opening is input to the comparison operation unit. In the comparison operation unit, the input detection opening is compared with a test opening which is a predetermined partial stroke of the valve stem, and a signal is output when the detection opening is equal to or less than the test opening. By inputting this signal to the changeover switch, the changeover switch is switched, and the changeover solenoid valve is changed from the excited state to the non-excited state. Due to this non-excitation, the flow path of the switching solenoid valve is switched, and the pressure oil supplied to the hydraulic cylinder flows into the cylinder, so that the valve rod, which has been closed to a predetermined test opening, moves in the opening direction again, and the main steam The stop valve is fully opened.

Therefore, since the valve stem opens and closes from a fully opened state to a predetermined test opening, by monitoring the movement of the valve stem accompanying this opening and closing, it is confirmed that the emergency stop of the main steam stop valve is surely performed. Is done. The test opening set by the test opening setter that sets the above-described predetermined test opening to an arbitrary opening from fully closed to fully open is set as the test opening and the set test opening and the opening detector The calculated opening is compared with the detected opening by the comparison operation unit. When the detected opening is equal to or less than the set test opening, the changeover switch is switched to open and close the valve stem from full open to the set test opening as described above. Check the movement and confirm that the closing operation of the valve stem at the time of emergency closure of the main steam stop valve is performed securely.

Further, by providing a throttle in a flow path for discharging the pressure oil in the cylinder of the hydraulic cylinder from the switching solenoid valve, the discharge of the pressure oil in the cylinder when the valve rod of the main steam stop valve is moved in the closing direction. Since the speed at which the main steam stop valve is performed is made slower, it is possible to prevent the main steam stop valve from closing to a predetermined test opening or a smaller opening than the preset test opening due to a calculation delay in the comparison calculation unit.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of a main steam stop valve provided with a stem-free test device according to an embodiment of the present invention and opened and closed by a hydraulic cylinder. In FIG. 1 and FIGS. 2 to 4 described later, the same components as those of the conventional example of FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted. FIG. 1 differs from the conventional example of FIG. 5 in the following.

The cylinder 31 of the hydraulic cylinder 30 is formed so as to surround the piston 3 to which the valve rod 4 is connected. A switching solenoid valve 33 is provided in the oil supply / discharge pipe 16 connected to the cylinder 31.
Is provided. The switching solenoid valve 33 forms a flow path that allows the pressure oil to be supplied to the hydraulic cylinder 30 through non-excitation to flow into the cylinder 31 through the oil supply / discharge pipe 16, and controls the pressure oil that is supplied to the hydraulic cylinder 30 by excitation. The flow is switched to the formation of a flow path for preventing the inflow into the cylinder 31 and discharging the pressure oil in the cylinder 31 to the outside through the oil discharge pipe 35 having the throttle 34.

The switching solenoid valve 33 is connected to an electric circuit 36 for energizing the solenoid valve.
The switching solenoid valve 33 is de-energized and energized according to the input. A lever 38 is attached to the valve rod 4, and this lever 38 is attached to a sensor rod 39 of the opening detector 40, and the opening detector 4
0 detects the stroke of the valve stem 4, that is, the opening degree via the lever 38.

The comparison operation unit 49 sets an arbitrary partial stroke, that is, a partial opening, of the entire stroke from the fully open to the fully closed position of the valve stem 4, which is preset in the test opening setting unit 48, as the test opening. Comparing and calculating the opening detected by the opening detector 40 with the test opening, and when the detected opening is equal to or less than the test opening,
A signal for switching the changeover switch 37 is output. With such a configuration, if the main steam stop valve 1 opens the electric circuit 36 by switching the changeover switch 37 to de-energize the changeover solenoid valve 33, the flow of the pressure oil into the oil discharge pipe 35 is prevented,
The pressure oil flows into the cylinder 31 of the hydraulic cylinder 30 from the oil supply / discharge pipe 16 via the switching electromagnetic valve 33. The piston 3 connected to the valve stem 4 moves in the rightward opening direction against the spring force of the closing spring 23 by the flowed pressure oil, and the main steam stop valve 1 is fully opened. In this fully opened state, the steam is supplied to the steam turbine through the main steam stop valve 1.

When the main steam stop valve 1 is fully opened and the main steam stop valve 1 is urgently closed, a test for confirming that the closing operation of the valve rod 4 is reliably performed is performed as follows. The changeover switch 37 is switched to close the electric circuit 36 and the changeover solenoid valve 33 is changed from non-excitation to excitation. When the switching electromagnetic valve 33 is excited, the pressure oil supplied to the cylinder 31 of the hydraulic cylinder 30 is blocked by the flow direction of the switching electromagnetic valve 33 shown in FIG. 34, the discharge speed is reduced and the discharge is performed. Due to the discharge of the pressure oil, the piston 3 connected to the valve stem 4 moves at a gentle speed in the left closing direction by the force of the closing spring 23. At this time, the stroke of the valve stem 4, that is, the opening, is detected by the opening detector 40, and a signal of the detected opening is input to the comparison operation unit 49.

In the comparison operation section 49, the input detected opening is compared with a test opening which is a partial stroke of an arbitrary valve rod previously set in the test opening setting device 48, and the detected opening is calculated. When the test opening is smaller than the test opening, a signal is output, and the switch 37 is switched by this signal to open the electric circuit 36. Therefore, the switching solenoid valve 33 is de-energized by opening the electric circuit 36, the piston 3 connected to the valve rod 4 moves in the right opening direction, and the main steam stop valve 1 is fully opened.

It should be noted that the gradual release of the pressure oil by the throttle 34 provided in the oil discharge pipe 35 is performed by slowing down the closing speed of the valve stem and delaying the operation by the comparison operation unit 49 so that the opening degree is smaller than the test opening degree. Not to be closed. By monitoring the reciprocating motion from the full opening of the valve stem 4 to the test opening as described above, it is possible to confirm that the closing operation of the valve stem 4 is reliably performed when the main steam stop valve 1 is urgently closed.

In this embodiment, the pressure oil in the cylinder 31 is discharged when the switching solenoid valve 33 is energized. However, the pressure oil in the cylinder 31 is discharged when the switching electromagnetic valve 33 is not energized. May be supplied with pressure oil. FIG. 4 is a flowchart showing the flow of a test for confirming the movement of the valve stem 4 of the main steam stop valve 1. The flow will be further described with reference to FIG. 1 based on FIG.

In FIG. 4, during turbine operation, step 5
When the changeover switch 37 is turned off at 0, the switchover solenoid valve 33 is de-energized at step 51 and the flow path of the pressure oil flowing through the switchover solenoid valve 33 is changed to the pressure oil supplied to the hydraulic cylinder 30. Flows into the cylinder 31 via the oil supply / discharge pipe 16 (in FIG. 3, the switching solenoid valve is opened in step 51).
Then, the pressure oil flows into the cylinder 31 to move the piston 3 connected to the valve rod 4 in the opening direction, and the main steam stop valve 1 is fully opened. At this time, the signal of the opening degree detected by the opening degree detector 40 is not input to the comparison operation unit 49.

When the main steam stop valve 1 is fully opened and the main steam stop valve 1 is urgently closed and the closing operation of the valve rod 4 is to be surely performed, the changeover switch 37 is set at step 50. Turn on. With this insertion, the opening detector 4
The signal of the detected opening degree at 0 is input to the comparison operation unit 49.
Then, the signal of the detected opening is input to the adder 45 by the comparison operation unit 49, and an arbitrary test opening 57 set in advance in the test opening setting unit 48 to monitor the movement of the valve stem 4. A comparison operation is performed, and an opening degree deviation 54 is calculated. If the opening deviation is larger than 0% in step 54, step 5
At 5, the switching solenoid valve 33 is excited, the flow path of the switching solenoid valve 33 is prevented from flowing into the cylinder 31 the pressure oil supplied to the hydraulic cylinder 30, and the pressure oil in the cylinder 31 is discharged to the oil discharge pipe 3.
4 (indicated by the switching solenoid valve in step 55 being closed in FIG. 4), and the pressure oil in the cylinder 31 is discharged from the oil discharge pipe 35, so that the piston 3 connected to the valve rod 4 is closed. Move in the direction. The stroke of the valve stem 4 at this time, that is, the opening is detected by the opening detector 40, and the detected opening is compared with the test opening 57 by the comparison operation unit 49, and the opening deviation 54 is 0% or less. At this time, a signal is output, and according to this signal, the changeover switch 37 in step 50 is switched off. As described above, the changeover solenoid valve 33 is de-energized in step 51 to open the changeover solenoid valve 33, and step 52 The main steam stop valve 1 is fully opened. At this time, the signal of the opening degree detected by the opening degree detector 40 is not input to the comparison operation unit 49.

Therefore, by monitoring the reciprocating motion of the valve stem from the full opening of the valve stem 4 to the test opening, it is confirmed that the closing operation of the valve stem 4 is surely performed when the main steam stop valve 1 is urgently closed. it can.

The provision of the test opening setting device 48 allows the main steam stop valve to be provided in a single main steam stop valve or a steam turbine having a plurality of main steam stop valves 1 in a steam turbine 58 as shown in FIG. Effective for valve stem-free test. That is, in a steam turbine having one main steam stop valve, the test opening can be set to the test opening by the test opening setting unit 48, through which the amount of steam that does not hinder the operation of the turbine flows. Further, as shown in FIG. 5, in the steam turbine 58 having a plurality of, for example, two main steam stop valves 1, the main steam stop valves 1 are fully closed one by one and the stem free test of the main steam stop valves 1 is performed. Can be performed by setting the test opening to the fully closed opening by the test opening setting device 48.

[0031]

As is apparent from the above description, according to the present invention, the main steam stop valve in the fully open state is operated by the above-described configuration according to the opening detected by the opening detector during the operation of the steam turbine. By monitoring the reciprocating motion of the valve stem of the main steam stop valve until the test opening is set to a predetermined predetermined test opening or an arbitrary opening from fully closed to fully opened,
It can be confirmed that the closing operation of the valve stem is reliably performed when the main steam stop valve is emergency closed when the steam to the steam turbine is shut off. In addition, without providing a test piston to move the piston of the hydraulic cylinder as in the past, during turbine operation,
Since the movement of the valve stem of the main steam stop valve can be confirmed, the structure is simplified, the cost is reduced, and the standardization and series of hydraulic cylinders can be easily obtained.

Also, by providing a throttle in the flow path for discharging the pressure oil in the hydraulic cylinder from the switching solenoid valve, a predetermined test opening or a preset test opening due to a calculation delay in the comparison calculation unit. It can be prevented from closing to a smaller opening.

[Brief description of the drawings]

FIG. 1 is a system diagram of a main steam stop valve provided with a stem-free test device according to an embodiment of the present invention and opened and closed by a hydraulic cylinder.

FIG. 2 is a stem free of a main steam stop valve showing a switching state of a switching solenoid valve when discharging hydraulic oil in a cylinder of a hydraulic cylinder when confirming movement of a valve stem of a main steam stop valve in FIG. 1; Partial system diagram of test equipment

FIG. 3 is a system diagram of a steam turbine having a plurality of main steam stop valves to which the stem free test apparatus of the main steam stop valve of FIG. 1 is applied.

FIG. 4 is a flowchart showing a flow when a stem-free test of the main steam stop valve of FIG. 1 is performed.

FIG. 5 is a configuration diagram of a main steam stop valve provided with a conventional stem-free test device and opened and closed by a hydraulic cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main steam stop valve 3 Piston 4 Valve rod 16 Oil supply / discharge pipe 30 Hydraulic cylinder 31 Cylinder 33 Switching electromagnetic valve 36 Electric circuit 37 Switching switch 40 Opening detector 48 Test opening setter 49 Comparison operation unit

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01D 21/00 F01D 17/10 F01D 17/24 F01D 17/26

Claims (2)

(57) [Claims] A valve rod connected to a piston of a hydraulic cylinder is reciprocated by supplying and discharging pressure oil to and from a cylinder through an oil supply / discharge pipe connected to the cylinder, thereby injecting and shutting off steam to a steam turbine. In the stem-free test device of the main steam stop valve, which checks the movement of the valve stem of the main steam stop valve during turbine operation, the device is provided in the oil supply / discharge pipe and is supplied to the hydraulic cylinder by switching between excitation and non-excitation. A switching solenoid valve for switching between formation of a flow path for allowing pressure oil to flow into the cylinder and formation of a flow path for preventing formation of the flow path and discharging the pressure oil in the cylinder to the outside; A change-over switch that turns off and on to energize and de-energize the electric circuit connected to the valve, an opening detector that detects the opening of the main steam stop valve with the stroke of the valve rod, and an opening detector. The test opening to be compared with the detection opening The test opening setter that sets the opening to an arbitrary opening from to fully open, and the opening detected by the opening detector is compared with the set test opening from the test opening setter, and when the opening is less than this opening, A stem-free test device for a main steam stop valve, comprising: a comparison operation unit that outputs a signal for switching a changeover switch. 2. A stem-free test apparatus for a main steam stop valve according to claim 1, wherein a throttle is provided in a flow path for discharging pressure oil in the cylinder of the hydraulic cylinder from the switching solenoid valve. .