JPH072678U - Water hammer prevention device for circulating water system - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the water hammer action from occurring in the circulating water pipe path due to the sudden closing of the butterfly valve. [Structure] A butterfly valve 11 interposed in a circulating water pipe 5 is structured such that a valve body 13 rotates in a valve casing 12.
This valve body 13 moves from the closed position to the fully open position. A valve body holding device 14 is arranged at the tip of the valve body 13 in the fully open position.
The valve body holding device 14 includes a fixing member 15 having a claw 15a that sandwiches the tip of the valve body 13, and a drive device 16 for driving the fixing member 15.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a thermal power plant and a nuclear power plant, and more particularly to a water hammer prevention device for a circulating water system which is used by being incorporated in a circulating water pipe path of a condenser.

[0002]

[Prior art]

 The condenser of a thermal power plant or a nuclear power plant generally uses seawater, river water, or water cooled by a cooling tower as cooling water, and this cooling water is introduced into the condenser via a circulating water pipe by a circulating water pump. It A condenser inlet valve and condenser outlet valve are provided at the inlet and outlet of the condenser for maintenance or shutoff of the condenser, and the cooling water warmed through the condenser is the outlet. It is returned to the sea or river or the cooling tower through the circulating water pipe on the side. In the case of a large diameter such as a circulating water pipe, a butterfly valve is generally used as the valve type, but the butterfly valve has the advantages of space saving and light weight, but on the other hand, the valve element is always in the flow path, so There is such a drawback. For example, in the event of a valve accident, if the valve body is in a free state due to damage to the valve body fixing pin, dropout of the drive unit connecting bolt, etc., the flow path is closed rapidly, resulting in abnormal pressure due to water hammer. As the pressure rises, the pressure waves cause destruction of condensers, valves, etc., causing great damage. The circulating water system will be described with reference to FIG.

Circulating water pump 2 supplies seawater as cooling water to condenser 1 via inlet side circulating water pipe 3. Then, this cooling water condenses the steam discharged from the steam turbine 4 in the condenser 1, and the cooling water that has finished the work is discharged to the outside of the system through the outlet side circulating water pipe 5. The circulating water pipes 3 and 5 are provided with a condenser inlet valve 6 and a condenser outlet valve 7, respectively.

[0004]

[Problems to be solved by the device]

 However, the conventional condenser circulating water system has the following drawbacks. That is, the pressure rises abnormally due to the water hammer effect caused by the rapid closing of the condenser outlet valve 7, resulting in the destruction of the condenser 1 or the valve body. The sudden closing event of the condenser outlet valve 7 is aggravated by the force of the water flow when the valve body becomes unrestrained due to the damage of the pin fixing the valve body and the valve stem, the failure of the valve drive device, etc. It is caused by the fully closed state. An object of the present invention is to provide a water hammer prevention device for a circulating water system, which prevents a water hammer effect from occurring in the circulating water pipe path due to the sudden closing of a butterfly valve.

[0005]

[Means for Solving the Problems]

 The present invention relates to a butterfly valve in a circulating water system including a butterfly valve in which a valve body rotates from a closed position to a fully open position in a valve casing to form a circulating water flow region leading to the front and rear of the valve body. It is characterized in that a valve body holding device is provided to restrain the movement of the valve body when the body is in the fully open position.

[0006]

[Action]

 Since the water hammer prevention device of the circulating water system according to the present invention is constructed in this way, it is always mechanically fixed when the valve body is in the fully open position even if the stop valve or the valve drive device fails. . It is possible to prevent the equipment of the circulating water system from being damaged by the water hammer effect.

[0007]

【Example】

 An embodiment of the present invention will be described with reference to FIG. In FIG. 1A, a butterfly valve 11 interposed in the circulating water pipe 5 is constructed so that a valve body 13 rotates in a valve casing 12. The rotation of the valve body 13 moves from a closed position where the valve body 13 is oriented at right angles to the seawater flow direction to a fully open position (position shown in the figure) which is parallel to the flow direction. The valve body holding device 14 is arranged at the tip of the valve body 13 in the fully open position.

The valve body holding device 14 is composed of a fixing member 15 having a claw 15 a that sandwiches the tip of the valve body 13 and a drive device 16 for driving the fixing member 15. As shown in Fig. 1 (b), the fixing member 15 is directed toward the valve body when the valve body 13 is at the fully open position, and is rotated 180 ° when the valve body 13 is at the closed position to move in the direction opposite to the valve body. Be directed.

FIG. 2 shows a control block. The interlock is constructed by a circuit so that the fixing member 15 rotates and retracts before closing the butterfly valve 11. In the holding operation, first, the valve body 13 is moved to the fully open position, and then the driving device 16 is operated to sandwich and fix the valve body 13 between the claws 15a of the fixing member 15. On the other hand, in the retracting operation, the fixing member 15 is first rotated to release the fixation while the valve body 13 is left as it is, and then the valve body 13 is moved to the closed position.

[0010]

[Effect of device]

 As is clear from the above, according to the present invention, even if a failure of the valve or the valve drive device occurs, the valve body can be restrained in the fully open position, and the rapid closing of the valve body can be prevented. Therefore, it is possible to reliably prevent damage to the device and the valve body.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a control logic diagram for operating the driving device of the present invention.

FIG. 3 is a configuration diagram showing a conventional circulating water system.

[Explanation of symbols]

 5 ... Circulating water pipe 11 ... Butterfly valve 13 ... Valve body 14 ... Valve body holding device 15 ... Fixing member

Claims (1)

[Scope of utility model registration request] 1. A butterfly valve in a circulating water system, comprising: a butterfly valve for rotating a valve body from a closed position to a fully open position in a valve casing to form a flow region of circulating water communicating with the front and rear of the valve body. A water hammer prevention device for a circulating water system, comprising a valve body holding device for restraining the movement of the valve body when the valve body is in the fully open position.