JPH0727658A - Gas leakage detection method - Google Patents

Abstract

PURPOSE:To obtain a method for detecting a small amount of leaked gas without malfunctioning. CONSTITUTION:A gas pressure detection sensor 2, a gas flow detection sensor 3, and an active pressure fluctuation device 10 are incorporated into a gas meter 1, supply gas pressure is allowed to fluctuate, the gas pressure and flow rate at this time are detected, and a gas leakage is determined according to the correlation between gas pressure and flow rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is mainly applied to a method for detecting a gas leak occurring in a city gas indoor piping and a gas appliance.

[0002]

2. Description of the Related Art In the case of a consumer of city gas, a gas meter is attached to the end of a lead-in pipe (serving pipe) drawn from a main pipe, and the gas meter and an indoor gas tap are connected by an indoor pipe. There is. In such a situation, the following two methods are generally practiced as means for detecting gas leakage from indoor piping and gas appliances.

A. When the flow rate of the gas passing through the gas meter is abnormally high, that is, when the gas meter detects a certain flow rate or more, it is determined that there is a gas leak and the gas is shut off.

B. The continuous use safety time of the gas appliance connected to the gas tap is set in advance, and the gas is shut off when the continuous use safety time is exceeded.

Incidentally, Table 1 shows an example of criteria for judging that there is a gas leak (gas ejection accident) when detecting the abnormal gas flow rate described in the above a, and Table 2 shows the continuation described in the above b. It shows an example of a standard for determining a gas leak by monitoring a usage safety time.

[0006]

[Table 1]

[0007]

[Table 2]

[0008]

However, the known examples described above have the following drawbacks.

With respect to a, when a very small amount is flowing, it cannot be detected as a gas leak, so that the gas may continue to flow without interruption, leading to a gas accident. On the contrary, when a gas appliance using a high calorie gas amount is used for a long time, it may be judged as a gas leak and shut off.

Regarding b, it is possible to make a judgment to prevent a gas leak accident by changing the continuous use safety time according to the amount of gas used, but a device with a larger amount of gas used has a shorter use time. However, it is not likely to cause a malfunction.

An object of the present invention is to propose a gas leak detection method capable of reliably detecting even a small amount of gas leak and not shutting off gas when the gas appliance is normally used. is there.

[0012]

The gas leak detection method according to the present invention is as follows.

A gas appliance is attached to the terminal of the gas leak inspection section, and the gas appliance is in a used state,
A supply gas pressure fluctuation device is attached to the upstream part of the gas leak inspection section, and a gas pressure detection sensor and a flow rate detection sensor are installed in the gas leakage inspection section, and the supply gas pressure is actively changed by the supply gas pressure fluctuation device, The gas pressure detection sensor and the gas flow rate detection sensor respectively detect the pressure fluctuation and flow rate fluctuation in the gas leak inspection section that occur at this time, and a correlation is recognized between the change in gas supply pressure and the change in gas flow rate. If there is a leak, a gas leak detection method that determines that there is a gas leak.

[0014]

[Function] In addition to the gas flow rate, a gas meter with a mechanism for detecting changes in the gas supply pressure corrects changes in the gas flow rate due to changes in the gas supply pressure on the instrument side when the gas supply pressure is actively changed. Without such a mechanism, the fluctuation of the gas supply pressure causes the fluctuation of the gas flow rate as it is. This is the case when there is a gas leak. Therefore, when a gas leak occurs, there is a correlation between the gas supply pressure and the gas flow rate.

On the other hand, a gas water heater, a bath kettle, etc. have a built-in gas governor in the equipment, and the gas governor absorbs the fluctuation of the gas supply pressure. It does not appear. Therefore, there is no correlation between the gas supply pressure and the gas flow rate. The present invention detects gas leakage by focusing on the correlation between gas supply pressure and gas flow rate.

The gas supply pressure is actively changed, the gas flow rate is detected by a gas meter, and the gas supply pressure is detected by a gas pressure detection sensor attached to the gas meter. This detected value is input to the correlation calculation circuit.
In the correlation calculation circuit, when the gas supply pressure is constant (however, there is a slight fluctuation range) and only the flow rate changes, the correlation calculation is not performed and the gas supply pressure is changed to If there is a correlation between the change and the change in gas flow rate, it is determined that there is a gas leak, and a signal is sent to the gas leak determination circuit (pressure fluctuation, flow rate fluctuation, correlation inference mechanism) to determine the gas leak. When the circuit determines that there is a gas leak, it shuts off the gas. Or at the same time, a gas leak alarm is issued.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is for explaining an embodiment of the present invention. 1 is a gas meter (microcomputer meter),
In the gas meter 1, a gas pressure detection sensor 2, a gas flow rate detection sensor 3, a gas cutoff valve 4, a correlation calculation circuit 5-1 and a gas leak determination circuit 5-2, an active pressure fluctuation device (for example, a governor, a valve). Etc.) 10 are incorporated.
6 is a supply pipe, 7 is an indoor pipe that connects the header 8 and the gas appliance 9 with a governor, and the supply gas that has entered the gas meter 1 from the supply pipe 6 is measured by the gas meter 1 and then the header 8 → indoors Flows from pipe 7 to gas appliance 9.

The gas supply pressure is actively varied by the active pressure fluctuation device 10, the gas flow rate is detected by the gas flow rate detection sensor 3, and the gas supply pressure is detected by the gas pressure detection sensor 2. This detected value is the correlation calculation circuit 5-
Input to 1. In the correlation calculation circuit, when the gas supply pressure is constant (however, there is a slight fluctuation range) and only the flow rate changes, the correlation calculation is not performed and the gas supply pressure is changed to When a correlation is recognized between the change and the change in the gas flow rate, it is determined that there is a gas leak, and a signal is sent to the gas leak determination circuit 5-2 (pressure fluctuation, flow rate fluctuation, correlation inference mechanism), When the gas leak determination circuit determines that there is a gas leak, the gas is shut off. Or at the same time, a gas leak alarm is issued.

FIG. 2 is a determination flow of the above embodiment.

[0020]

As described above, according to the present invention, if there is no correlation between the gas supply pressure and the gas flow rate, it is possible to determine that a gas appliance is being used and no gas leakage has occurred, so that a large amount of gas can be obtained. The false cutoff does not occur when the equipment that uses the gas is used for a long time. If there is a correlation,
By inferring from the pressure fluctuation, the flow rate fluctuation, and the strength of the correlation, it is possible to make a finer determination for the gas leak determination. Further, fluctuations in the gas supply pressure are caused by the surrounding households using the gas, and therefore the cycle and magnitude of fluctuations are unpredictable depending on the surrounding environment. Therefore, by determining the cycle and size of the gas supply pressure and actively fluctuating it, the accuracy of gas leakage estimation (correlation calculation accuracy, estimation accuracy in the calculation inference mechanism) increases, and the calculation speed and calculation amount are increased. Is also reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a gas leak determination flow.

[Explanation of symbols]

 1 Gas Meter 2 Gas Pressure Detection Sensor 3 Gas Flow Rate Detection Sensor 4 Gas Cutoff Valve 5-1 Correlation Calculation Circuit 5-2 Gas Leakage Determination Circuit 6 Service Pipe 7 Indoor Pipeline 8 Header 9 Gas Appliance 10 Active Pressure Fluctuation Device

Claims (1)

[Claims] 1. A gas appliance is attached to a terminal of the gas leak inspection section, the gas appliance is in a use state, a supply gas pressure fluctuation device is attached to an upstream portion of the gas leak inspection section, and the gas leak inspection section is also installed. A gas pressure detection sensor and a flow rate detection sensor are installed inside, and the supply gas pressure fluctuation device actively fluctuates the supply gas pressure. A gas leak detection method that determines that there is a gas leak when a detection sensor and a gas flow rate detection sensor detect each, and a correlation is recognized between a change in gas supply pressure and a change in gas flow rate.