JPH0249905A - Driving device for self pressure type separation valve - Google Patents

Abstract

PURPOSE:To always secure a specified valve operation time in a self pressure type separation valve wherein self-contained steam is supplied to a valve driving part to open/close a valve body by switchingly adopting separately supplied gas as a driving source when the temperature of the valve driving part is low. CONSTITUTION:A self pressure type separation valve 1 has a valve driving part 1b including a piston ring 10 directly connected to a valve body 1c, steam can be supplied to an upper air chamber 8 thereof from a driving stem pipe 4a communicated a body 1a through a control valve 6a for close air supply, and also supplied to a lower air chamber 9 through a control valve 12 for open exhaust brancingly connected a driving steam pipe 4b. A three-way valve 15 is provided on the driving steam pipe 4a, and to one port thereof a high pressure nitrogen gas source is connected through a nitrogen pipe 14. The three- way valve 15 is changed over so that self-contained steam is utilized at high temperature detection, on the other hand, nitrogen gas at low temperature detection according to outputs of a temperature detector 16 provided on the valve driving part 1b.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a drive device for a self-pressure isolation valve in a nuclear power plant, etc., which uses steam generated from a steam generator of a nuclear reactor as a drive source. Regarding.

(Prior Art) For example, self-pressure type isolation valves that contain steam generated in a reactor in a nuclear power plant and supply this steam as a driving source to its own valve drive unit to open and close the valve are conventionally known. As shown in the cross section of the isolation valve and the configuration diagram of its drive device (representing the valve closed state) in Figure 2, the valve drive system uses the steam 3 flowing from the body 1a of the self-pressure type isolation valve 1 through the piping 2 to drive steam piping. 4a, double check valve 5, drive steam piping 4
The lower air of the valve drive part 1b in the upper part of the body 1a passes through the closed air supply control valve 6a, the orifice 7 for flow restriction, and the closed air sub-control valve 6b connected in parallel with the closed air supply control valve 6a. It is connected to supply the chamber 8. Further, since the self-pressure isolation valve 1 is in a closed state, the piston ring 10, which is directly connected to the valve body 1C and partitions the lower air chamber 8 and the lower air chamber 9, is pushed down.

Further, an open supply air control valve 11 is connected between the driving steam pipe 4b and the lower air chamber 9, and an open exhaust control valve 12 and a closed exhaust control valve 13 are provided in the upper air chamber 8 and the lower air chamber 9, respectively. are connected with one end open to the outside.

Further, the double check valve 5 normally communicates the driving steam piping 4a and the driving steam piping 4b, and is constructed by connecting a nitrogen piping 14 to one side for performing test operations when there is no steam 3. There is.

To open this self-pressure type isolation valve 1, close the closed air supply control valve 6a, the closed air supply sub-control valve 6b, and the closed exhaust control valve 13,
Open the open air supply control valve 11 and the open air exhaust control valve 12. As a result, the steam 3 in the body 1a passes through the driving steam piping 4a, the double check valve 5, and the driving steam piping 4b, reaches the upper air chamber 9 via the open air supply control valve 11, and pressurizes the piston ring 10. Push up to open valve body 1C. At this time, the steam in the upper air chamber 8 is discharged to the outside of the valve drive section 1b via the opening/exhaust control valve 12.

Next, in order to switch the self-pressure type isolation valve 1 from the open state to the closed state, the open supply air control valve 11 and the open exhaust control valve 12 are closed in order to push down the piston ring 10, and the closed exhaust control valve 13 is closed. The closed supply air control valve 6a, which supplies steam 3 to the upper air chamber 8, is opened. As a result, the valve body 1
C is closed, and at this time the orifice 7 limits the amount of steam flowing into the upper air chamber 8 to adjust the valve closing speed.

However, for example, when a steam isolation valve is to be changed from an open state to a closed state during operation of a nuclear reactor, the operation must be performed within a predetermined time range for the safety of the reactor. In other words, it is necessary to close the reactor faster than the upper limit time allowed when the reactor is isolated, and later than the lower limit time determined by the permissible amount of disturbance to the reactor pressure. Normally, when an atomic coupler is in operation, the main body of the self-pressure isolation valve 1 is at a high temperature, so the flow rate of the driving steam layer to the upper air chamber 8 is adjusted by the orifice 7 to prevent the self-pressure isolation valve 1 from closing prematurely. are doing. On the other hand, when the plant is started up, the main body of the self-pressure isolation valve 1 is still at a low temperature, so a large amount of the driving steam is cooled and condensed in the upper air chamber 8 of the valve drive part 1b, pushing the piston ring 10 downward. As a result, the closing time of the self-pressure isolation valve 1 becomes longer. Therefore, in the past, as a countermeasure against this problem, in addition to the closed supply air control valve 6a with the orifice 7 inserted, the drive steam supply path was provided with a closed supply air sub-control valve 6b in parallel with this drive steam supply path, and the atomic coupler was At startup, the closed supply air sub-control valve 6b is opened together with the closed supply air control valve 6a, and the amount of steam flowing into the upper air chamber 8 is increased to ensure valve closing within a predetermined time.

(Problem to be Solved by the Invention) Since the temperature conditions of the self-pressure type isolation valve 1 differ depending on the start-up or operation of the plant, the open air supply control valve 6a is designed with an orifice 7 inserted in consideration of this. In addition to installing two systems of equipment and piping for the sub-control valve 6b and the closing air supply sub-control valve 6b, the drive device and control become complicated, such as having to use independent operation and combined operation each time the valve is closed. ,
This has the disadvantage of causing malfunctions and erroneous operations.

The present invention has been made in view of the above, and its purpose is to simplify the valve drive system, and to detect the temperature of the self-pressure isolation valve body and automatically select the drive source when closing the valve. An object of the present invention is to provide a highly reliable driving device for a self-pressure type isolation valve that can always ensure a predetermined closing time regardless of the temperature of the self-pressure type isolation valve body.

[Structure 1 of the Invention (Means for Solving the Problems) A valve driving section is provided, the interior of which is partitioned by a movable section connected to a valve body, and steam contained in the valve driving section is supplied as a driving source. In self-pressure type isolation valves that open and close the valve by
Temperature detection means provided in the valve driving section, means for selecting a high or low temperature of this temperature signal, and means for switching the driving source according to this signal are provided in the valve driving source supply path, so that when the valve driving section is at a high temperature, When the valve drive unit is at a low temperature, a separately supplied gas is selected as the drive source.

(Function) The valve drive system is simplified to one system, the temperature of the valve drive part is detected by the temperature detection means, and when the temperature of the self-pressure isolation valve body is sufficiently high, the selection means is switched to the drive source switching means. In response, the switching means supplies steam to the valve drive section by issuing a signal indicating that steam is to be supplied from the isolation valve body. In addition, when the temperature of the self-pressure isolation valve body is low, the selection means and switching means supply high-pressure nitrogen gas from the nitrogen pipe to the valve drive section in response to the low temperature signal from the temperature detector. Since the operating pressure does not decrease in the drive section, a predetermined valve operating time can always be ensured.

(Example) An embodiment of the present invention will be described with reference to the drawings.

Note that the same components as those in the prior art described above are given the same reference numerals, and detailed explanation thereof will be omitted.

Figure 1 is a cross section of the self-pressure type steam isolation valve and a configuration diagram of its driving device (showing the valve closed state).
A valve drive unit which is provided with a valve body 1C and an upper air chamber 8 and a lower air chamber 9 partitioned by a piston ring 10 directly connected thereto]b
The drive system includes a drive steam pipe 4a from the body 1a, a three-way valve 15 serving as a drive source switching means, a drive steam pipe 4b, and a closed air supply control valve 6a and an orifice 7 for flow restriction. Valve drive unit 1 located at the top of the body 1a
It is connected to the upper air chamber 8 of b. In addition, an open supply air control valve 11 is connected between the driving steam pipe 4b and the lower air chamber 9, and roughly speaking, the lower air chamber 8 and the lower air chamber 9 each have an open exhaust control valve 12 and a closed exhaust control valve 11, respectively. A valve 13 is connected, and each has one end opened to the outside. Further, one end of the three-way valve 15 is connected to the nitrogen pipe 14, which communicates with a high-pressure nitrogen gas source (not shown). A temperature sensor 16, which is a temperature detection means, is attached to the valve drive unit 1b, and the output temperature signal is transmitted to a selection circuit 17, which is a selection means, and the selection circuit 17 switches the three-way valve when the temperature is lower than a preset temperature. 15
A switching signal is issued. In the three-way valve 15, a switching valve (not shown) is always energized by a spring (not shown) to allow steam to flow, but upon receiving a switching signal from the selection circuit 17, an electromagnet (not shown) is energized to resist the spring. switch the selector valve to the nitrogen gas side, and connect dry high-pressure nitrogen gas to nitrogen pipe 1.
4, the steam is supplied to the upper air chamber 8 of the valve drive unit 1b via the drive steam piping 4b, the closed air supply control valve 6a, and the orifice 7.

Next, the effects of the above configuration will be described. If the temperature of the self-pressure isolation valve 1 body is high during plant operation, the selection circuit 17 that receives the high temperature signal from the temperature detector 16 selects the three-way valve 15.
The steam 3 from the body 1a is supplied to the driving steam piping 4b without outputting any particular signal to the body 1a. Here, self-pressure isolation valve 1
When opening, open air supply control valve 11 and air exhaust control valve 1
2 is opened, and the closed air supply control valve 6a and the closed exhaust control valve 13 are closed. The steam 3 is supplied from the driving steam pipe 4b to the lower air chamber 9 via the open air supply control valve 11, and is then supplied to the lower air chamber 9.
0 to open the valve body 1C. Note that the steam in the upper air chamber 8 is discharged to the outside of the valve drive unit 1b via the open/exhaust control valve 12. In addition, when closing the open self-pressure type isolation valve 1, in order to push down the piston ring 10, the open air supply control valve 11 and the open exhaust control valve 12 are closed, the closed exhaust control valve 13 is opened, and the upper The closed air supply control valve 6a that supplies steam 3 to the air chamber 8 is opened. This closes the valve body 1C, but at this time the orifice 7 limits the amount of steam flowing into the upper air chamber 8 to adjust the valve closing speed.

When the temperature of the self-pressure isolation valve 1 body is low, such as when starting up a plant, the temperature detector 16 detects the low temperature of the valve drive part 1b and outputs a low temperature signal to the selection circuit 17, and the selection circuit 17 issues a switching signal to the three-way valve 15, the three-way valve 15 is energized, the switching valve operates, and the dry high-pressure nitrogen gas is communicated from the nitrogen pipe 14 to the driving steam pipe 4b. At this time, the three-way valve 15 blocks the steam 3 from the body 1a. To close the open valve, close the air supply control valve 11 and the open/exhaust control valve 12 in order to push down the piston ring 10, and open the close/exhaust control valve 13. The closed supply air control valve 6a that supplies nitrogen gas is opened. As a result, the high-pressure nitrogen gas is supplied to the upper air chamber 8 of the valve drive unit 1b located at the upper part of the body 1a via the closed supply air control valve 6a and the flow rate restriction orifice 7, and presses the piston ring 10. Press down to close the valve body 1C. At this time, the orifice 7 limits the amount of nitrogen gas flowing into the upper air chamber 8 to adjust the valve closing speed.

As a result, dry high-pressure nitrogen gas, whose pressure and volume do not change significantly depending on temperature conditions, is supplied to the valve drive unit 1b as a drive source, so even if the temperature of the valve drive unit 1b is low, the predetermined valve closing time can be maintained. Since it can be secured, it is possible to control the reactor etc. without putting strain on it. Next, when the valves are opened, the closed air supply control valve 6a and the closed exhaust control valve 13 are closed, and the open air supply control valve 11 and the open exhaust control valve 12 are opened. The high pressure nitrogen gas from the three-way valve 15 is supplied to the open air supply control valve 1.
1 to the lower air chamber 9, the piston ring 10 is pushed up and the valve body 1C is opened. Note that the nitrogen gas in the upper air chamber 8 is discharged to the outside of the valve drive unit 1b via the open/exhaust control valve 12.

Note that when the valve driving part 1b is at a low temperature as described above, the valve opening operation is initially performed using nitrogen gas as the driving source, but after the valve is opened, the valve driving part 1b is warmed by the steam 3 passing through the body 1a. Its temperature gradually rises. As a result, the temperature signal from the temperature sensor 16 changes from low temperature to high temperature,
When this reaches the set value in the selection circuit 17, the three-way valve 1
Since the switching signal to 5 is stopped, the three-way valve 15 is no longer excited, and the switching valve automatically switches the nitrogen gas supply to the lower air chamber 9 to steam 3 by the spring force, so the drive source is switched off from the precious high-pressure nitrogen gas. Consumption is suppressed and replaced with self-steam 3 from the original body 1a of the self-pressure type isolation valve 1, maintaining the current status of the valve and assuming future operating conditions.

[Effects of the Invention] According to the present invention, the valve can be opened and closed within a predetermined period of time regardless of the temperature conditions of the self-pressure type isolation valve, so that the demands of related equipment can be easily met. Furthermore, since the drive system is simplified, failures and maintenance are reduced and reliability is improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an isolation valve and a configuration diagram of a drive device according to an embodiment of the present invention, and FIG. 2 is a cross-section diagram of a conventional isolation valve and a configuration diagram of a drive device. 1...Self-pressure type isolation valve, 1a...Body, 1b
... Valve drive unit, 1G... Valve body, 3... Steam, 4a, 4b... Drive steam piping, 6a... Control valve for closed supply air, 7... Orifice, 8
... Upper air chamber, 9... Lower air chamber, 10.
...Piston ring, 11...tlJ control valve for open air supply, 12...iti control valve for air exhaust, 13...
Closed exhaust control valve, 14...Nitrogen piping, 15
...Three-way valve, 16...Temperature detector, 17...Selection circuit. Agent Patent Attorney Norio Ogo Figure 1 Figure 2

Claims (1)

[Claims] In a self-pressure type isolation valve, which is provided with a valve driving part partitioned off by a movable part connected to a valve body, and which opens and closes the valve body by supplying steam contained in the valve driving part, the valve driving part is equipped with: Temperature detection means, means for selecting a high or low temperature of the temperature signal, and means for switching a drive source according to a signal from the selection means are provided in the valve drive source supply path, so that when the valve drive section is at a high temperature, the self-contained steam is switched to a low temperature state. A drive device for a self-pressure isolation valve, characterized in that the drive source is sometimes a separately supplied gas.