JPH05141204A - Trip device for steam turbine emergency block valve - Google Patents

Abstract

PURPOSE:To provide a trip device for a steam turbine emergency block valve which is simplified in hardware and software by eliminating a resetting electromagnetic valve required for conventional devices. CONSTITUTION:A trip electromagnetic valve 4 and a logic valve 6 are combined together in a hydraulic cylinder 3 for an emergency block valve 1 to form a hydraulic circuit, so that a drain port F in the logic valve can be opened by the switching operation of the trip electromagnetic valve in emergency to drain operating oil from the hydraulic cylinder through the drain port for closing the emergency block valve. In the trip device, a resetting guided oil throttle hole 6c is opened to the valve body 6a of the logic valve to deliver operating oil into the hydraulic cylinder through the trip electromagnetic valve so that operating oil delivered through the trip electromagnetic valve can be guided into a pressure room G for the hydraulic cylinder through the guided oil throttle hole in the logic valve in resetting to open the emergency block valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency stop valve trip device applied as a main steam stop valve and a reheat steam stop valve of a steam turbine.

[0002]

2. Description of the Related Art First, FIG. 3 shows a conventional configuration of the above-mentioned emergency shutoff valve and a hydraulic circuit attached thereto as an emergency stop system of a steam turbine. That is, the emergency shutoff valve 1 is composed of a valve body 2 and a hydraulic cylinder 3 (a single-acting cylinder with a spring) as a valve operating actuator, and the hydraulic cylinder 3 has a trip solenoid valve (2-position spring offset type electromagnetic switching). (Valve) 4, reset solenoid valve (2-position spring offset type solenoid switching valve) 5, and logic valve 6 are combined as shown to form a hydraulic circuit. In order to secure high reliability for the operation of the emergency shutoff valve, generally two solenoid valves for trip 4 and logic valve 6 are provided as shown in the figure.

Next, the operation of the above configuration will be described. When the emergency stop valve 1 is reset so as to be opened according to the start-up of the turbine, the circuit A shown in FIG.
In the state where hydraulic oil is supplied to the controller, a reset command is given to a controller (not shown), and the trip solenoid valve 4 and the reset solenoid valve 5 are first excited. As a result, the hydraulic oil is guided from the circuit A to the upper chamber E of the logic valve 6 via the trip solenoid valve 4, circuits C and D, and pressurizes the valve body 6a as pilot pressure from above to close the drain port F at the closed position. Lock to. In this state, the reset solenoid valve 5 has the circuit A
Hydraulic oil is blocked. Subsequently, when the reset solenoid valve 5 is demagnetized, the hydraulic fluid is guided from the circuit A to the pressure chamber G of the hydraulic cylinder 3 via the reset solenoid valve 5 and the circuit B. This causes the piston 3a of the cylinder 3 to move to the spring 3b.
Stroke operation against the above, and the emergency stop valve 1 is opened.
And this state is maintained during the operation of the steam turbine.

On the other hand, when the emergency stop valve 1 is closed to stop the steam turbine rapidly in an emergency, a trip command is given to the controller. As a result, the trip solenoid valve 4
Is demagnetized, the solenoid valve 5 for resetting is excited to perform switching operation, the circuit A of hydraulic oil is blocked, and the hydraulic oil in the upper chamber E of the logic valve 6 is connected to circuits C, D and the solenoid valve 4 for trip. Through the drain port H. Therefore, the pilot pressure acting on the upper chamber of the logic valve 6 is lost, and the valve body 6a of the logic valve moves upward against the spring 6b (the lower chamber of the logic valve 6 has the spring 3b of the cylinder 3).
(The hydraulic pressure of the upper chamber G pressurized by is applied) to open the drain port F. As a result, the hydraulic oil contained in the upper chamber G of the cylinder 3 is discharged through the drain port F of the logic valve 6, so that the emergency shutoff valve 1 is rapidly closed by being biased by the spring 3b.

[0005]

As described above, in the conventional trip device for the emergency shutoff valve, the hydraulic circuit of the hydraulic cylinder 3 includes the trip solenoid valve 4, the logic valve 6, and the emergency shutoff valve 1. The reset solenoid valve 5 for opening the closed solenoid valve from the closed state is required, and a control step for switching the reset solenoid valve 5 from excitation to demagnetization is required in the control process of the reset operation. For this reason, the hardware and software of the trip device are complicated, and it takes time and effort to manage the operation test and maintenance in order to maintain the soundness of the device.

The present invention has been made in view of the above points, and an object thereof is to improve a hydraulic circuit, thereby omitting a reset solenoid valve required in a conventional device and simplifying hardware and software aspects. (EN) Provided is a trip device for a steam turbine emergency shutoff valve.

[0007]

According to the present invention, the above object is achieved by opening an oil guide throttle hole for resetting, which feeds hydraulic oil to a hydraulic cylinder through a trip direction control valve in a valve body of a logic valve. It

The logic valve may be installed in a head cover of a hydraulic cylinder so that a reset oil guide throttle hole is directly opened toward the pressure chamber of the cylinder. An electromagnetic valve is used for the trip directional control valve, and a hydraulic circuit is constructed so that the solenoid is always energized to apply hydraulic fluid pressure to the secondary side logic valve, including resetting the emergency shutoff valve. Good.

[0009]

In the above structure, when the trip solenoid valve is excited during the opening operation of the emergency shutoff valve, the hydraulic oil is hydraulically supplied from the secondary side of the trip solenoid valve through the oil guide throttle hole opened to the logic valve. Since it is introduced directly into the pressure chamber of the cylinder, this resets the emergency shutoff valve and keeps it open. On the other hand, in an emergency, when the trip solenoid valve is demagnetized based on the trip command, the secondary side pressure of the solenoid valve escapes through the drain port. As a result, the logic valve performs a switching operation with almost no influence of the oil guide throttle hole to open the drain port leading to the pressure chamber of the hydraulic cylinder, and rapidly close the emergency stop valve. That is, the trip solenoid valve,
Since the logic valve will function as both trip and reset, this will eliminate the need for a reset-only control valve in addition to the trip solenoid valve and logic valve.
The opening / closing operation of the emergency stop valve can be performed without any problems.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In the figure, the same members corresponding to those in FIG. 3 are designated by the same reference numerals. First, FIG. 1 shows a hydraulic circuit of an embodiment of the present invention corresponding to FIG. 3, in which there is no reset solenoid valve as compared with the configuration of FIG. 3, and instead, on the secondary side of the trip solenoid valve 4, For the connected logic valve 6, its valve body 6
A small oil guiding throttling hole 6c for resetting is formed in a and penetrates between the upper and lower chambers.

With such a construction, in order to open the emergency stop valve 1 from the closed position, the trip solenoid valve 4 is excited. As a result, the hydraulic fluid is guided from the circuit A through the solenoid valve 4 to the upper chamber E of the logic valve 6, and the hydraulic pressure is used as pilot pressure to push down the valve body 6a to close the drain port F, and the hydraulic fluid The upper chamber E of the logic valve is gradually introduced into the pressure chamber G of the hydraulic cylinder 3 through the oil guide throttle hole 6c formed in the valve body 6a. As a result, the hydraulic cylinder 3 strokes the piston 3a downward against the spring 3b to open the emergency stop valve 1. Although the pressure is balanced between the upper and lower chambers of the logic valve 6 after the emergency stop valve is opened, the valve body 6a is biased by the spring 6b, so the drain port F remains closed. keep.

On the other hand, when the steam turbine is brought to an emergency stop in an emergency, the solenoid of the trip solenoid valve 4 is demagnetized based on the trip command. As a result, the hydraulic fluid circuit A is blocked on the primary side of the solenoid valve 4, and the secondary side is opened to the drain port H. Therefore, the oil pressure in the upper chamber E of the logic valve 6 escapes from the drain port H of the trip solenoid valve 4 and is lost, so that the valve body 6a resists the spring 6b due to the pressure difference from the oil pressure applied from the hydraulic cylinder 3 side. The switching operation is performed and the drain port F is opened. As a result, the hydraulic oil contained in the pressure chamber G of the hydraulic cylinder 3 is discharged through the drain port F of the logic valve 6, and the emergency stop valve 1 rapidly closes to cut off the steam flow sent to the turbine. In the process of this trip operation, the oil guide throttle hole 6 drilled in the valve body 6a of the logic valve 6 is used.
Part of the hydraulic oil from the hydraulic cylinder 3 side through c
The oil guide throttle hole 6c has a small diameter, and the valve body 6a is held at the switching position where the drain port F is opened by the pressure reducing action of the orifice.

Next, the logic valve 6 is connected to the hydraulic cylinder 3
FIG. 2 shows a specific structure incorporated in the. In the figure,
Reference numeral 3c is a cylinder tube of the hydraulic cylinder 3, 3d is a head cover of the cylinder, 3e is an oil supply manifold attached to the head cover 3d, and 3f is an oil supply flange connected to an oil guide pipe with the outside. Here, the logic valve 6 is embedded and built in the inside of the head cover 3d.
Then, the oil guide throttle hole 6c drilled in the valve body 6a of the logic valve 6 at this installed position opens directly toward the pressure chamber G of the cylinder 3. Incidentally, 6d is a stopper rod for restricting the stroke range of the valve body 6a. Although not shown, the trip solenoid valve is mounted on the manifold 3e and communicates with the upper chamber E of the logic valve 6 via an oil guide passage 3g bored in the manifold 3e.

[0014]

The trip device for the emergency shutoff valve according to the present invention comprises:
Since it is configured as described above, the following effects can be obtained. (1) For the logic valve combined with the directional control valve for trip, by piercing the oil guide throttle hole for resetting in the valve body, the directional control valve for trip is opened at the time of valve opening operation of the emergency stop valve. It is possible to introduce the hydraulic oil sent via the oil passage directly into the hydraulic cylinder for operating the emergency stop valve through the oil guide throttle hole of the logic valve. No longer needed. Therefore, the configuration, control system, and maintenance of the trip device can be greatly simplified as compared with the conventional device.

(2) The logic valve is incorporated in the header cover of the hydraulic cylinder, and the oil-conducting throttle hole is provided so as to open directly toward the pressure chamber of the cylinder. The route of the oil guide hole drilled in the manifold is greatly simplified, and the hole drilling during manufacturing can be done easily.

(3) Further, an electromagnetic valve is used as the trip directional control valve, and the electromagnetic valve is always used in the excited state even when it is reset, so that an unexpected situation such as loss of power source occurs. Even in such a case, the operation of the steam turbine can be stopped by closing the emergency shutoff valve, whereby a failsafe type emergency stop system can be established.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a trip device according to an embodiment of the present invention.

FIG. 2 is an assembly structure diagram of the logic valve and the hydraulic cylinder in FIG.

FIG. 3 is a hydraulic circuit diagram of a conventional trip device for an emergency shutoff valve.

[Explanation of symbols]

 1 Emergency stop valve 3 Hydraulic cylinder 3 Cylinder head cover 4 Trip solenoid valve 6 Logic valve 6a Valve body 6c Oil guide throttle hole

Claims (3)

[Claims] 1. A trip device for rapidly closing an emergency stop valve of a steam turbine in an emergency, wherein a hydraulic circuit is constructed by combining a hydraulic cylinder of the emergency stop valve with a trip direction control valve and a logic valve. When the emergency directional control valve is switched in an emergency, the drain port of the logic valve is opened, hydraulic oil is discharged from the hydraulic cylinder through the drain port, and the emergency stop valve is closed. A trip device for an emergency shutoff valve for a steam turbine, wherein an oil guide throttle hole for resetting, which sends hydraulic oil to a hydraulic cylinder through a trip directional control valve, is opened. 2. The trip device according to claim 1, wherein the logic valve is incorporated in the head cover of the hydraulic cylinder, and an oil guiding throttle hole for resetting is directly opened toward the pressure chamber of the cylinder. Trip device for emergency shutoff valve for steam turbine. 3. The trip device according to claim 1, wherein the trip directional control valve is a solenoid valve that normally energizes a solenoid including resetting the emergency shutoff valve to apply hydraulic oil pressure to the secondary side logic valve. A trip device for an emergency shutoff valve for a steam turbine, characterized in that