JPS63235799A - Compressed air feeder - Google Patents

Abstract

PURPOSE:To prevent any pressure drop in an IA system from occurring, by installing a pressure-regulating valve which makes pressure in an instrument compressed air system constant at time of backup operation. CONSTITUTION:In case of backup operation from an SA system 9 to an IA system 1, if an SA backup valve 16 is opened, a pressure regulating valve 101 opens as well. This pressure-regulating valve 101 is controlled of its opening by a pressure controller 102. If pressure in the IA system 1 goes down, opening of the pressure-regulating valve 101 is throttled to some extent whereby pressure in the IA system 1 is kept constant. Consequently, such a situation that pressure in the IA system 1 is abnormally lowered and thereby a plant is scrammed, is surely prevented from occurring.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a compressed air supply device in a nuclear power plant, and particularly relates to an instrumentation compressed air system (hereinafter referred to as an IA system) and an in-station compressed air system. (hereinafter referred to as the SA system), and performs backup operation from the SA system to the IA system when the pressure in the IA system decreases.

(Prior art) Inside a nuclear power plant, there is an IA system that supplies dry compressed air to air-operated valves or control valves and other instrumentation and control equipment, and an IA system that supplies dry compressed air to air-operated valves or control valves and other instrumentation control equipment, as well as compressed air to cleaning equipment that uses air pressure and air-driven air tools. An SA system is installed to supply air. Therefore, the configurations of the conventional IA system and SA system will be explained with reference to FIG. Reference numeral 1 in the figure is an IA system, in which two air compressors t12 are installed in parallel. A rear cooler 3 is connected to these air compressors 2, and a steam/water separator 4 is further connected thereto. These steam/water separators 4 are connected to one air storage tank 6 via a check valve 5, and are supplied to each device as instrumentation compressed air via these dehumidifiers HH8.

Next, the configuration of the SA system 9 will be explained. Number 10 in the figure
are two air compressors arranged in parallel, and each of these air compressors 10 is connected to a rear cooler 11 and further connected to a steam/water separator 12.

A check valve 13 is connected to each of the steam/water separators 12, and one air storage tank 14 is also connected thereto. This air storage tank 1
4, compressed air is supplied to the site where the in-house compressed air system is used.

An SA backup line 15 is provided between the secondary side of the check valve 7 of the IA system 1 and the secondary side of the air storage tank 14 of the SA system 9. An SA backup valve 16 is inserted into this SA backup line 15. On the other hand, a pressure switch 17 is inserted on the primary side of the dehumidifier 8 of the IA system 1, and a signal 817 from the pressure switch 17 causes the SA backup valve 16 to be connected via the three-way solenoid valve 18.
The opening and closing of the door is almost restricted. That is, the SA backup valve 16
is normally closed. For example, if both air compressors 2 of the IA system 1 lose their functions, the pressure on the primary side of the dehumidifier 8 decreases, and this is detected by the pressure switch 17.

The signal s17 from the pressure switch 17 switches the three-way solenoid valve 18 to exhaust air. As a result, control air from a positioner (not shown) is no longer transmitted to the diaphragm of the backup valve 16, and the backup valve 16 is forcibly opened by the built-in spring. As a result, a backup operation is performed from the SA system 9 to the IA system 1.

Note that the reference numeral 19 in the figure is a check valve.

The above configuration has the following problems. That is, S
Backing up from the A system 9 to the IA system 1 means supplying compressed air from the air compressor 10 of the SA system 9 to both the SA system 9 and the IA system 1. At this time, the air compressor*io of the SA system 9 is normally used with a capacity that is 50% of the maximum capacity of the SA system 9. Therefore, when backing up from SA system 9 to IA system 1, it is assumed that the amount of compressed air used by both systems exceeds the capacity of air compressor 110 of SA system 9, and in that case, due to insufficient supply, IA system 1 and There is a possibility that the pressure of both the SA system 9 will decrease. If the pressure of the IA system 1 becomes lower than the minimum holding pressure, it will become impossible to continue operation of the plant, and furthermore, it is expected that the plant will scram.

(Problem to be Solved by the Invention) In this conventional configuration, if the usage of the IA system and SA system exceeds the capacity of the SA system air compressor, capacity will be insufficient and both systems will be There is a problem that the pressure of the IA system decreases, and the plant scrams due to the pressure decrease of the IA system.The present invention was made based on these points, and its purpose is to reduce the pressure of the IA system. An object of the present invention is to provide a compressed air supply device capable of preventing a scram in a plant due to the drop in air.

[Structure of the Invention] (Means for Solving the Problems) That is, the compressed air supply device according to the present invention includes a backup piping disposed between an instrumentation compressed air system and an in-house compressed air system, and a When the pressure of the instrumentation compressed air system drops below a preset pressure, the valve opens to supply compressed air from the in-house compressed air system to the instrumentation compressed air system via the backup piping. A backup valve is inserted into the station compressed air system and is fully open during normal operation, and its opening is controlled by the pressure of the instrumentation compressed air system during backup operation from the station compressed air system to the instrumentation compressed air system. The present invention is characterized by comprising a pressure regulating valve that maintains the pressure of the instrumentation compressed air system at a constant level by adjusting the pressure.

(Function) In other words, a pressure regulating valve is installed in the in-house compressed air system, and when the pressure of the instrumentation compressed air system decreases, this pressure regulation valve throttles its opening to ensure the amount of compressed air supplied to the instrumentation compressed air system. The pressure is maintained constant. This prevents a pressure drop in the instrumentation compressed air system and even a scram in the plant.

(Embodiment) An embodiment of the present invention will be described below with reference to the tube 1@ and FIG. 2. It should be noted that the same parts as in the prior art are denoted by the same reference numerals and the explanation thereof will be omitted. The reference numeral 101 in the figure is an SA system positive pressure regulating valve. This pressure regulating valve 101 is a pressure controller 10
2 controls its opening degree. A signal 5103 is input to this pressure controller 102 from a pressure transmitter 103 inserted in the IA system 1. This signal 5103 is also input to the pressure switch 104, and a signal 5104 from this pressure switch 104 is input to the three-way solenoid valves 18 and 105. That is, when the pressure in the IA system 1 becomes less than a preset pressure, a signal 5104 is outputted to the three-way solenoid valves 18 and 105 via the pressure switch 104. The output of this signal 5104 switches the three-way solenoid valves 18 and 105 to the exhaust side.

Thereby backup valve 18 and pressure 1IW1 valve 1
05 is forcibly opened. The opening degree of the pressure regulating valve 105 is controlled by the pressure controller 102.

In other words, the pressure controller O-la 102 transmits pressure! 1103
Input the pressure signal 5103 of IA system 1 from
103, a control signal s101 is output to the pressure regulating valve 101 in order to keep the pressure of the IA system 1 constant. Specifically, if the pressure in the IA system 1 decreases, control is performed to reduce the opening degree of the pressure regulating valve 101. Further, the pressure regulating valve 101 is provided with a minimum opening degree locking mechanism. This is due to the following reasons. One of the SAAs2 functions is to supply compressed air for air masks, and this is done for the purpose of reducing radiation exposure when workers work under high radiation conditions. Therefore, in this embodiment, a minimum opening degree locking mechanism is installed in the pressure regulating valve 101 to ensure compressed air for the air mask in any case.

The operation will be explained based on the above configuration. First, during normal operation, the SA backup valve 16 is closed and the I
The A system 1 is supplied with compressed air from the air compressor 2 of the IA system 1, and the SAAs 2 is supplied with compressed air from the SAAs 2 air compressor 8110. At this time, the pressure regulating valve 101 is in a fully open state.

Next, the case where SAAs2 is backed up to IAA1 will be explained. For example, due to a failure of the air compressor 8!2 of IA system 1, the dehumidifier of IA system 1! When the primary side pressure of I8 decreases, the pressure switch 104 is activated by the engagement from the pressure transmitter 103, and outputs a signal 5104 to the three-way solenoid valves 18 and 105.

As a result, the SA backup valve 16 opens and the pressure regulating valve 101 also opens. This allows S.A.A.
Backup operation from s2 to IA system 1 is started. The opening degree of this pressure regulating valve 101 is controlled by a pressure controller 102. That is, when the pressure in the IA system 1 decreases, the opening degree of the pressure regulating valve 101 is reduced, thereby maintaining the pressure in the IA system 1 constant. Therefore, IA
A situation in which the pressure in the system 1 drops abnormally and causes a scram in the plant is reliably prevented.

Next, the operation of the minimum opening degree locking mechanism of the pressure regulating valve 101 will be explained. That is, the opening degree of the pressure regulating valve 101 is adjusted to maintain the primary side pressure of the dehumidifying @ 118 of the IA system 1 constant, but the opening degree is not reduced below a certain certain value.

In other words, this is to ensure the air supply for the air masks of the workers, which is the SAAs2 function. Therefore, the above-mentioned minimum opening degree locking mechanism is provided to prevent the opening degree from being narrowed down below that value.

According to this embodiment, the following effects can be achieved.

■When backing up IA system 1 by SA system 9, IA system 1
It is possible to reliably prevent a pressure drop and prevent a situation such as a plant scram.

(2) Also, since the pressure regulating valve 102 is equipped with a minimum opening degree locking mechanism, the minimum required compressed air for the SAAs2 is reliably secured.

[Effects of the Invention] As detailed above, according to the compressed air supply II according to the present invention, during the backup operation of the IA system by the SA system, the IA system
It is possible to reliably prevent a situation such as a pressure drop in the A system and a resulting plant scram, and the effects of this are great, such as being able to maintain the health of the plant.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are diagrams showing one embodiment of the present invention.
Figure 2 is a system diagram of the compressed air supply system during normal operation, Figure 2 is a system diagram of the compressed air supply system during backup operation, and Figure 3 is a system diagram of the compressed air supply system during backup operation.
The figure is a system diagram of a conventional compressed air supply device. 1...Instrumentation compressed air system (IA system), 9...In-house compressed air system C8A system), 15...Backup piping, 1
6... Backup valve, 101... Pressure regulating valve. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) Backup piping installed between the instrumentation compressed air system and the station compressed air system, and when the pressure of the instrumentation compressed air system inserted into this backup piping falls below a preset pressure. A backup valve that, when opened, supplies compressed air from the in-house compressed air system to the instrumentation compressed air system via the backup piping, and a backup valve that is inserted into the in-house compressed air system and is fully open during normal operation. and a pressure regulating valve that maintains the pressure of the instrumentation compressed air system at a constant level by adjusting its opening according to the pressure of the instrumentation compressed air system during backup operation from the in-house compressed air system to the instrumentation compressed air system. A compressed air supply device characterized by: (2) The compressed air supply device according to claim 1, wherein the pressure regulating valve is equipped with a minimum opening degree locking mechanism.