JPS6275004A - Turbine control device - Google Patents

Abstract

PURPOSE:To prevent the air from intruding into the inside of a cylinder when a control valve is replaced with a new one by providing a non-return valve to a leak plug of a hydraulic piston for operating a steam valve and inclining both feed oil port and oiling port of a manifold block control valve. CONSTITUTION:A non-return valve 23 is provided to a leak plug 16 of a hydraulic piston 4 that drives a steam valve 1. Both a servo-valve (7)-feed-oilport 21 and a hydraulic cylinder (3)-oiling-port 19 of a manifold block 18, to which the servo-valve 7 is connected, are inclined to the horizontal surface in such a manner that the servo-valve (7) sides of both ports are situated higher than the other sides. In addition, a stop valve 26 is provided to a hydraulic circuit 25 bypassing a cutoff valve 11 that is provided in a hydraulic circuit, which is used to supply the control oil to the servo-valve 7. With this contrivance, even when the servo-valve is removed, a leak port 16a is closed with the non- return valve 23, while the oil surface is formed within both oiling port 19 and feed oil port 21, thereby preventing the air from intruding into the cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a turbine control device, and more particularly to a control device that allows a servo valve for driving a steam valve to be replaced even during turbine operation.

[Technical background of the invention and its problems]

Generally, in a steam turbine plant, a steam valve or safety valve is installed to rapidly cut off the working fluid flowing into the turbine when the load is cut off, keep the turbine rotation speed as low as possible, and control its speed and load. In addition to the normal speed and load control devices, a device is provided which allows the valve to be rapidly closed.

FIG. 4 is a diagram showing the control mechanism of the steam valve, in which the valve body 1a of the steam valve 1 is connected to the hydraulic piston 4 of the hydraulic cylinder 3 via the valve rod 2. The hydraulic piston 4 of the hydraulic cylinder 3 is biased in the direction of fully opening the valve by a spring 5 for fully opening the valve, and a lower chamber 6 of the hydraulic piston 4 is provided with high pressure control via a servo valve 7 operated by a valve position command signal. Oil is supplied and configured to operate the hydraulic piston 4 in the valve opening direction. A disc dump valve 8 is provided at the bottom of the hydraulic cylinder 3, and a lower chamber 9 of the disc dump valve 8 is supplied with pressure oil from the emergency hydraulic line C via a quick-acting solenoid valve 10. At all times, the disk dump valve 8 is kept fully closed. Furthermore, a part of the pressure oil that has passed through the rapid-acting solenoid valve 10 is supplied via a Δrefrigerant 12 to the Arai 11 which supplies and cuts off the high-pressure control oil to the servo valve 7. be.

On the other hand, a switch rod 13 is connected to the valve stem 2 of the hydraulic cylinder 3, and a limit switch 14 and a differential transformer 15 are disposed along the switch rod 13, so that the hydraulic piston of the hydraulic cylinder 3 4
This allows the position of the steam valve to be detected, that is, the opening degree of the steam valve.

At normal times, the disk dump valve 8 as described above is fully closed, and high-pressure control oil is supplied to and discharged from the piston lower chamber 6 of the hydraulic cylinder 3 under the control of the servo valve 7, and the oil is supplied and discharged through the valve stem 2. The opening of the steam valve 1 is controlled. On the other hand, when the quick-acting solenoid valve 10 is switched, the pressure oil in the disk dump valve 8 is completely drained, the disk dump valve 8 is suddenly closed, and the hydraulic piston 4 is rapidly lowered to C in the figure, causing the steam valve to open. 1 is suddenly closed. ? The steam valve listed below is
As mentioned above, it is rapidly closed to control the amount of steam flowing into the steam turbine during normal operation and to suppress steam turbine overspeed by reducing the load to 0 load +1' and '1.

By the way, the IJ-
The valve 7 performs important functions and is periodically overhauled and inspected. 1
]-Jin, '1rl-John, Noirta is clogged' is a common problem, and the 1v-vo valve needs to be replaced.

When replacing this lift valve, it is necessary to remove the steam valve under control from the control system, and either stop the steam turbine or turn the It is necessary to supplement that function. However, in nuclear power plants and large-capacity thermal power plants that have a base load and require time for start-up and shutdown, stopping the turbine and avoiding a drop in operating rate is a major loss. Therefore,
It is necessary to adopt the latter method, that is, to replace the servo valve while continuing turbine operation.

The basic concept of this online maintenance is as described in U.S. Patent No. 4,040,600, where the Arai 11 in FIG. 1 ~ Valve (
(not shown) is to be replaced during turbine operation. Therefore, these replacement operations are performed after fully closing the steam valve using a valve test mechanism.

However, due to the air that entered the hydraulic cylinder when the servo valve 7 was removed and the air inside the replaced servo valve, abnormal operation may occur due to transient phenomena in the control oil when the control state is restored. There are some problems.

That is, the hydraulic piston 4 shown in FIG. 4 is generally provided with a leak plug 16, as shown in FIG. 5, in order to prevent control oil from deteriorating.
The control oil is circulated through a leak hole 16a provided in the hydraulic piston 4 to the bottom of the hydraulic piston 4.
Furthermore, a wire 1717 for adjusting the leakage flow rate is inserted through the hole 16a. Further, as shown in FIG. 6, since the servo valve 7 is attached to the manifold block 18 at the bottom of the hydraulic cylinder 3, the servo valve 7
If the above manifold block 1 is removed,
Air enters into the hydraulic cylinder 3 through the oil supply hole 19 of 8 and the like. However, this intruded air and new
When the air inside the servo valve is returned to the control state after replacing the servo valve, it causes an abnormality in the position of the hydraulic piston 6 or the opening of the steam valve 1, which has a great effect on the operation of the steam turbine. There are problems such as interfering with the operation of the power station.

[Purpose of the invention]

In view of these points, the present invention has been devised to provide a turbine control system that minimizes the intrusion of air when replacing the valve, and also makes it possible to easily remove some of the air that has entered after the replacement. The aim is to obtain equipment.

[Summary of explanation]

The present invention provides a reverse 11-valve in the leak plug provided in the hydraulic screws 1 to 1 for operating the steam valve, and also provides a control valve supply oil hole formed in a manifold block to which the control valve is connected and a hydraulic screw for operating the steam valve. The oil supply hole to the hydraulic cylinder is inclined with respect to the horizontal plane so that it is located on the control valve side or -L side, and the oil supply hole installed in the oil EF circuit that supplies control oil to the control valve is bypassed and directly installed. It is characterized by having a bypass hydraulic circuit that allows oil to be supplied to the control valve supply oil hole, and which is connected to the right side of the valve, and is used for hydraulic cylinders when replacing control valves such as servo valves or test valves. This is designed to minimize air intrusion into the interior, and to facilitate the discharge of air that has entered.

(Embodiment of the invention) Hereinafter, an embodiment of the present invention will be described with reference to Figs. The explanation is omitted.

As shown in FIG. A leak plug 16 is attached to a through hole 22 that communicates with the lower surface. The leak plug 16 is provided with a hole 16a that communicates the lower part of the hydraulic screws 1 to 4 with the inside of the through hole 22, and the leak hole 6a in A is for adjusting the leak flow rate. Lie 1
A reverse 11 valve 2 is inserted into the top end of the wire 17 of A to prevent the control oil from flowing only from below to above the hydraulic piston 4.
3 is installed.

On the other hand, as shown in FIG. 3, a servo valve 7 is attached to a manifold block 18 installed at the bottom of the hydraulic cylinder 3. Control oil is supplied to the manifold block 18 from the servo valve Oil f of the cylinder 3 [oil supply hole 19 that supplies 4 Jt to the dome chamber 6 of the piston 4, drain hole 20
A servo valve supply oil hole 21 for supplying control oil to the valve 7 is bored. And the oil supply hole 19
, and the ribo valve supply oil hole 21 are inclined with respect to the horizontal plane so that the open end on the servo valve 7 side is upward.

In addition, as shown in FIG. 1, a bypass hydraulic circuit 25 that bypasses the hydraulic well 11 is connected to the hydraulic circuit 24 that supplies control oil to the servo valve 7 described in -1-. A first valve 26 is installed at 25.

Therefore, at all times, the lower chamber 6 of the hydraulic piston 4
When control oil is supplied to the hydraulic piston 4, the hydraulic piston 4 moves upward and the steam valve 1 is controlled in the opening direction. A predetermined oil pressure is applied. Therefore, the check valve 23 is pushed up by the oil pressure, and a portion of the control oil is leaked into the leak hole 1.
The oil is drained through the upper chamber of the hydraulic piston via 6a, and the control oil is circulated.

Therefore, when replacing the J-bo valve, that is, when attempting to fully close the one-stroke steam valve during a valve test, the rapid-acting solenoid valve 10 is energized to cut off the emergency oil, and the disk dump valve 8 The lower hydraulic pressure disappears, the disk dump valve 8 opens, the control oil in the lower chamber 6 of the hydraulic piston 4 is discharged to the drain line, and the steam valve is fully closed via the hydraulic piston 4. Then, the disk dump valve 8 closes again due to spring force.

However, when the servo valve 7 is removed after the steam valve is fully opened as described above, the control oil in the lower chamber 6 of the hydraulic piston 4 leaks out to the outside due to the weight of the oil. The leak hole 16a of the plug 16 is blocked by the check valve 23, preventing the inflow of air, and the inside of the lower chamber 6 becomes negative pressure.However, since the oil supply hole 19 is inclined,
As shown in FIG. 3, an oil level is formed in the oil supply hole 19,
No more control oil will leak out. Further, even if the control oil flows out due to air entering through a small gap between the hydraulic piston 4 and the inner wall of the cylinder, the amount of leakage is almost negligible.

In addition, since the servo valve supply oil hole 21 is also inclined, an oil level is formed within the servo valve supply oil hole 21, and air cannot enter upstream from the servo valve supply oil hole 21. will be stopped. Furthermore, although the control oil in the drain hole 20 flows out, it does not cause air to enter the control hydraulic circuit.

Therefore, after replacing the novo valve, only a small amount of air that has entered the new servo valve will exist in the control hydraulic circuit. However, when the stop valve 26 is opened and a slight opening signal is given to the servo valve 7 to make it slightly open after the replacement of the servo valve is completed, the control oil is transferred from the bypass hydraulic circuit 25 to the new 4-novo valve 7. , flows into the oil supply hole 19 of the manifold block 18, the servo valve supply oil hole 21, and the lower chamber 6 of the hydraulic piston 4, and the check valve 23 is closed due to the inflow of this control oil. Afterwards, it is discharged to the outside along with the control oil. Therefore, no air remains in the control oil system.

In addition, although the servo valve was explained in the above embodiment, the same can be applied to a test valve.

〔Effect of the invention〕

Since the present invention is configured as shown in (a) above, it is possible to minimize the intrusion of air into the hydraulic circuit when replacing the valve, test valve, etc. during the operation of the turbine. It is also easy and reliable to release the intruded air, making it possible to safely replace servo valves, etc. 1. It is possible to prevent problems that may interfere with the operation of the turbine.

[Brief explanation of drawings]

Fig. 1 is a schematic system diagram showing an embodiment of the steam turbine control scheme of the present invention, Fig. 2 is a partial cross-sectional view of the same leak plug section, and Fig. 3 is a cross-sectional view of the 1j-Bo valve f] section. , FIG. 4 is a schematic system diagram of a conventional steam turbine control device, FIG. 5 is a sectional view of a conventional leak plug section, and FIG. 6 is a sectional view of a conventional servo valve mounting section. DESCRIPTION OF SYMBOLS 1...Steam valve, 4...Hydraulic piston, 7...Reevo valve, 8...Disk dump valve, 11...Shiarai, 16...Leak plug, 18...Manifold block, 19... Oil supply hole, 20... Drain hole, 2
1... Servo valve supply oil hole, 23... Check valve, 26...
...stop valve. Applicant's agent Sato -Yu No. 1@

Claims (1)

[Claims] A check valve is installed on the leak plug provided on the hydraulic piston for operating the steam valve, and a control valve supply oil hole formed in the manifold block to which the control valve is connected and an oil supply hole for the hydraulic cylinder for operating the steam valve are installed. The stopper is tilted with respect to the horizontal plane so that the control valve side is located upwards, and also allows oil to be directly supplied to the control valve supply oil hole by bypassing the block provided in the hydraulic circuit that supplies control oil to the control valve. A turbine control device comprising a bypass hydraulic circuit having a valve.