JPH0467876A - Gas leakage cutoff valve - Google Patents

Abstract

PURPOSE:To shorten a time to monitor gas leakage by setting the values of plural pressure sensors at preset values different mutually and lower than that of gas supply pressure, and setting a control valve at a closed state when the pressure sensor detects that the value becomes less than a gas leakage allowable value in a prescribed time. CONSTITUTION:The pressure sensors 3, 3 are arranged in a state communicating with a distribution hole 2b extending from a connection part 2a, and the values of them are set at the preset values different mutually and lower than that of the gas supply pressure P1. A controller cuts off the distribution of the connection parts 2a, 2a by operating the control valve 5 based on a detection signal when the detection signal representing the occurrence of the gas leakage is transmitted as a result of detection of the gas leakage by the pressure sensors. Also, the upper plane of a gas leakage cutoff valve 1 is comprised in such a way that it can be opened/closed freely by a cap 20, and the control valve 5 can be manually operated by operating a manual lever 22 in a state where the cap 20 is removed. The side plane of the gas leakage cutoff valve 1 is comprised in such a way that it can be opened/closed freely by a side cover 25, and the preset pressure values of the pressure sensors 3, 3 can freely be changed in a state where the side cover 25 is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a gas leak cutoff valve that detects gas leaks by measuring pressure changes in gas supply pipes.

"Prior Art" A method for detecting gas leakage in a pressure detection type is to install a pressure sensor at a point lower than the pressure used for boat fishing (standard 280 zzH, O) and perform the following procedure.

(2) As shown in FIG. 3, after opening the tank valve and supplying gas (approximately 200 to 300 zzHtO) for a predetermined period of time, the valve is closed.

■If there is no leak in the pipeline, the gas pressure will be maintained at a constant value like CI during the gas leak monitoring time (11-1,), but if there is a gas leak, both The pressure decreases according to C2, C8, and C4.

■Like C3 and C4, DA within the monitoring time (1111)
Anything that reaches below this point will keep the valve closed and sound an alarm.

(2) When a small leak within the safe range C1 and C2 are secured at or above the DA point within the monitoring time (11-1,), the valve is opened and the valve can be used.

"Problem to be Solved by the Invention" However, in the conventional example, even if the gas pipe capacity and leakage amount are determined, the gas supply pressure (P) is 200 to 33
Since the value of 0xmHxO is indeterminate, the time taken to reach the DA point changes, making it impossible to clearly detect a gas leak.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gas leakage cutoff valve that can stably shorten the time required to reach a gas leakage tolerance value.

"Means for Solving the Problems" The gas leak cutoff valve of the present invention is provided with a plurality of pressure sensors for measuring the pressure inside the gas supply pipe, and each of these pressure sensors is lower than the gas supply pressure. The gas leakage valve is set to low and different set values, and includes a control device that closes the on-off valve based on this detection signal when these pressure sensors detect that the gas leakage falls below the permissible gas leakage value within a predetermined time. It is characterized by the fact that

"Operation" After setting the plurality of pressure sensors to the gas leak detection monitoring pressure and the gas leak permissible pressure lower than the gas leak detection monitoring point, and opening the on-off valve to reach the gas leak detection monitoring pressure, Close the on-off valve and monitor for gas leaks. When the gas pressure falls below the gas leakage allowable pressure after a predetermined period of time, a transmission signal is sent from the pressure sensor via the control device to keep the on-off valve closed, and the on-off valve is closed.

"Embodiment" An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1(a) and 1(b) are diagrams showing the gas leakage cutoff valve 1 of this embodiment, and the gas leakage cutoff valve 1 has connection parts 2a, 2a with the gas supply pipe (path shown). The outer surface of the casing 2 is formed by a casing 2 that protrudes laterally from the direction in which the gas supply pipe extends. Inside this casing 2, there are two pressure sensors 3 for measuring the pressure inside the gas supply pipe, and an on-off valve 5 that opens and closes the gas supply pipe based on the detection signals of these pressure sensors 3.3. The structure is as follows.

The pressure sensors 3.3 are disposed in communication with the communication holes 2b extending from the connecting portion 2a, and are set to different setting values that are lower than the gas supply pressure P1. When the pressure sensor 3.3 detects that the gas leakage falls below the permissible value within a predetermined period of time, the detection signal is sent to the control bag, which will be described later. (path shown).

The on-off valve 5 is a valve for opening and closing an opening between a partition plate 2c provided between the connection parts 2a and the one connection part 2a, and is a valve for opening and closing an opening between the partition plate 2c and the one connection part 2a. It is configured to include a main seat 8 that can be opened and closed directly, and an operating mechanism IO for operating the main seat 8. The operating mechanism IO is a seat holder that supports the main seat 8! 1, a plunger 12 connected to the seat holder If, a diaphragm I3 and a spring 14 that apply a biasing force to the plunger I2, and a coil magnet 15 that operates the plunger 12.

As a result of the gas leak detection by the pressure sensor 3.3, the control device
When a detection signal indicating the occurrence of gas leakage is transmitted, the flow control valve 5 is operated based on this detection signal to cut off the flow between the connecting portions 2a, 2a.

The upper surface of the gas leakage cutoff valve 1 of this embodiment is configured to be able to be opened and closed by a cap 20, and the valve 5 can be opened and closed by operating a manual lever 22 with the cap 20 removed.
can be operated manually. The side surface of the gas leak cutoff valve 1 is configured to be openable and closable by a side cover 25.
With the pressure sensor 3.3 removed, the set pressure value of the pressure sensor 3.3 can be changed freely.

Next, an example of use of the gas leak cutoff valve 1 of this embodiment will be described with reference to FIG. 2.

First, the pressure sensor 3.3 is connected to two points P, (gas leak detection monitoring pressure) and P, (gas leakage allowable pressure), which are lower than the pressure P when using normal gas, (standard 280 x Ht O). Set.

(2) Open the on-off valve 5 to introduce gas, and close the on-off valve 5 when it is detected that the pressure has reached P.

■If there is no leak in the sealed gas pipeline, the pressure P will not change as shown by the solid line C3 in Figure 2, but if there is a leak, the amount of leak will increase as the solid line C8, C5, C
4, the time to reach the pressure P becomes shorter.

(2) The time it takes to reach pressure P from pressure P varies depending on the pipe capacity and leakage amount, but once the pipe capacity is determined on the equipment, the leakage amount can be determined by measuring the time.

■If the safe limit of leakage amount is shown by solid line C5, 1, -
1. If the pressure sensor 3.3 at the pressure P operates during the time period , it will notify that there is a leak exceeding the specified value and the on-off valve 5 will not be opened.

(2) If the pressure P does not reach within the specified time (5t+), the on-off valve 5 is automatically opened again, and gas is supplied through the connections 2a, 2a to continue use.

According to the gas leak cutoff valve l of this embodiment, the gas leak monitoring time can be shortened.

Furthermore, by setting the set value of the pressure sensor 3 lower than the gas supply pressure P, gas leak detection can be started in a stable state.

"Effects of the Invention" The gas leak cutoff valve of the present invention is provided with a plurality of pressure sensors for measuring the pressure inside the gas supply pipe, and these pressure sensors are all lower than the gas supply pressure and mutually The pressure sensors are set to different set values, and when these pressure sensors detect that the gas leakage falls below the allowable gas leakage value within a predetermined time, the control device closes the on-off valve based on this detection signal. Therefore, the gas leak monitoring time can be shortened.

Further, by setting the set value of the pressure sensor to be lower than the gas supply pressure, an excellent effect is achieved in that gas leak detection can be started in a stable state.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG.
a) is a plan view of the gas leakage cutoff valve, FIG. 1(b) is a sectional view of the same side, and FIG. 2 is a data diagram showing the usage state of the above embodiment.
FIG. 3 is a data diagram showing usage conditions of a conventional gas leakage shutoff valve. ■... Gas leak cutoff valve, 3... Pressure sensor, 5... Open/close valve.

Claims (1)

[Claims] A gas leak cutoff valve that is connected to a gas supply pipe and is equipped with an on-off valve that opens and closes the gas supply pipe, and is provided with a plurality of pressure sensors for measuring the pressure inside the gas supply pipe. The pressure sensors are all set to different set values that are lower than the gas supply pressure, and when these pressure sensors detect that the gas leakage falls below the allowable value within a predetermined time, the pressure sensor A gas leak cutoff valve characterized by comprising a control device that closes the on-off valve.