JP2837082B2 - Leakage inspection method at return in fluidic gas meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting leakage in a fluidic gas meter of a metering type in which a fluid vibration is generated and a gas flow rate is obtained from the fluid vibration after an emergency shut-off valve is operated and then returned. Applied.

[0002]

2. Description of the Related Art In a gas meter, the usage of gas is monitored by a microcomputer, and when the usage is abnormal, or when an earthquake of a certain seismic intensity or higher occurs, for example, an emergency shutoff valve is operated to reduce the flow of gas. A membrane microcomputer gas meter configured to shut off is known.

In this gas meter, after the emergency shut-off valve is operated, it is necessary to return the emergency shut-off valve in order to restart the gas supply. At this time, if the emergency shut-off valve is suddenly opened, for example, the plug of the gas appliance is opened and there is a danger of outflow of raw gas. Therefore, the emergency shut-off valve is opened after taking the following procedure.

First, the emergency shut-off valve is opened for 2 minutes. During this time, one pulse of the flow rate pulse is generated when the measuring membrane moves for one cycle. Therefore, when this pulse is input, the emergency shut-off valve is closed again and the gas leaks. Check the situation, and if there is no pulse input, leave the emergency shut-off valve open.

[0005]

However, the above-described leak check method has the following disadvantages. a. Opening the emergency shut-off valve for 2 minutes and confirming the generation of a pulse would require a lot of trouble and time to restart the supply if any one unit was operated at the same time due to an earthquake, for example. Recovery is delayed. b. As shown in Table 1, the amount of leakage determination differs depending on the measurement range (number) of the gas meter, so that the operation becomes complicated.

[0006]

[Table 1]

An object of the present invention is to propose a leakage inspection method at the time of return in a fluidic gas meter which does not have the disadvantages described in the above a and b.

[0008]

The structure of the leak inspection method at the time of return in the fluidic gas meter according to the present invention is as follows. A gas flow path extending from the gas inlet to the nozzle of the fluidic device, write set an emergency shut-off valve to stop the flow of gas in an emergency Mutotomoni, off the portion of the nozzle
In fluidic gas meter comprising Nde write set of row sensors, the time of returning the emergency shut-off valve, after recovering the gas pressure in the inner tube by temporarily opening the <br/> emergency shutoff valve,
Closing the emergency shut-off valve, the re-opening the emergency shut-off valve again after a predetermined time has elapsed, the flow rate of the gas when this re-opened
A leakage inspection method at the time of return in a fluidic gas meter that determines that there is gas leakage when detected .

[0009]

The emergency shut-off valve is activated when an abnormal flow rate or an earthquake of a certain seismic intensity or higher occurs to stop the gas. When the emergency shut-off valve operated in this manner is reopened, the emergency shut-off valve is once opened, the pressure in the inner pipe is restored to a predetermined gas pressure, and then the emergency shut-off valve is closed again. Then, after a certain time has elapsed, the emergency shutoff valve is opened. At this time, if there is a gas leak, the gas pressure in the inner pipe is reduced, so a gas flow is generated in the nozzle portion of the fluidic element, and the gas flow causes fluid vibration or a flow sensor attached to the nozzle portion. A gas flow is detected. As described above, when a gas flow is detected, it is determined that there is a gas leak, and the emergency shutoff valve is immediately closed.

On the other hand, if no gas flow is detected, it is determined that there is no gas leakage, and the emergency shutoff valve is kept open to enable the use of gas.

[0011]

FIG. 1 shows a fluidic gas meter embodying the present invention. 1 is a gas meter main body, 2 is a fluidic element, 3 is a gas inlet, 4 is a gas flow path, 5 is an emergency shutoff valve, 6 is a nozzle, 7 is a reset button, 8 is a fluid vibration generation chamber, and 9 is a gas outlet. , This is the inner pipe (indoor pipe)
Is tied to

FIG. 2 is an explanatory diagram of the leak inspection unit.
Denotes a flow rate calculation circuit, 11 denotes a leak inspection circuit, 12 denotes a shutoff valve drive circuit, and 13 denotes an inner pipe side gas pressure detection sensor. In the above embodiment, when the emergency shutoff valve 5 is operated and then reopened, the shutoff valve drive circuit 12 opens the emergency shutoff valve 5 in response to a signal from the leak inspection circuit 11. Then, the gas pressure in the inner pipe is detected by the gas pressure detection sensor 13, and when the predetermined pressure is recovered, the emergency shutoff valve 5 is closed. Thereafter, the waiting time of, for example, 30 seconds is counted by the counter, and after the lapse of time, the emergency shutoff valve 5 is opened again.
With this opening, when the fluidic element 2 or a flow sensor (not shown) detects a gas flow, it is determined that there is a gas leak, and the emergency shutoff valve 5 is immediately closed.

On the other hand, when the gas flow is not detected, it is determined that there is no gas leakage, and the emergency shutoff valve 5 is kept open to enable the use of gas.

[0014]

As described above, according to the present invention, when the emergency shut-off valve is operated and the gas is stopped and then reopened, the emergency shut-off valve is once opened to recover the gas pressure in the inner pipe, and then re-opened. When the emergency shutoff valve was closed and waited for a certain period of time, when the gas flow was not detected when the emergency shutoff valve was opened again, it was determined that there was no gas leakage, the emergency shutoff valve was kept open, and the gas flow was detected. At this time, it is determined that there is a gas leak, and the emergency shutoff valve is immediately closed. As a result, the following effects are obtained.

A. The time for once opening the emergency shutoff valve and restoring the gas pressure in the inner pipe may be several tens of seconds, and the time for once closing the emergency shutoff valve and performing the leak inspection may be several tens of seconds. As a result, the inspection time can be reduced to 1/2 to 1/3 as compared with the conventional leak inspection method.

B. Since the leak inspection can be automated by the leak inspection circuit, the speed of the leak inspection after the simultaneous operation due to an earthquake or the like can be increased to speed up the recovery.

C. If there was a gas leak, the valve was closed once and waited for several tens of seconds.If there was a gas leak and the pressure on the downstream side of the valve dropped, gas would flow at once when the valve was opened. High detection sensitivity even for gas leaks.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a fluid gas meter embodying the present invention.

FIG. 2 is an explanatory diagram of a leak inspection method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fluidic gas meter main body 2 Fluidic element 3 Gas inlet 4 Gas flow path 5 Emergency shutoff valve 6 Nozzle 7 Reset button 8 Vibration generating chamber 9 Gas outlet 10 Flow rate calculation circuit 11 Leakage inspection circuit 12 Shutoff valve drive circuit 13 Gas pressure detection sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields investigated (Int. Cl. ⁶ , DB name) G01F 1/00 G01F 1/20 G01M 3/00 G01M 3/26 G08B 21/00

Claims (1)

(57) [Claims] 1. A gas flow path extending from the gas inlet to the nozzle of the fluidic device, write set an emergency shut-off valve to stop the flow of gas in an emergency Mutotomoni, flow portion of the nozzle
In fluidic gas meter comprising Nde write set the sensor, after the time for returning the emergency shut-off valve, restored the gas pressure in the inner tube to temporarily open the emergency shut-off valve, closing the <br/> emergency shutoff valve a certain time the re-opening the emergency shut-off valve again after the flow rate of the gas when the reopening is detected
A leakage inspection method at the time of return in a fluidic gas meter that determines that there is a gas leak when it is performed.