JP3117841B2 - Gas leak detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mainly applied to a method for detecting gas leaks generated in indoor pipes of city gas and gas appliances.

[0002]

2. Description of the Related Art In the case of city gas consumers, a gas meter is attached to the end of a service pipe (service pipe) drawn from the main pipe, and the gas meter and an indoor gas tap are connected by an indoor pipe. I have. In such a situation, the following two methods are generally implemented 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 flow rate equal to or higher than a predetermined value, it is determined that there is gas leakage, and the gas is shut off.

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

[0005] Table 1 shows an example of a criterion for judging that there is a gas leak (gas ejection accident) when the abnormal gas flow rate described in the above item a is detected. It shows an example of a criterion for determining a gas leak by monitoring a safe use time.

[0006]

[Table 1]

[0007]

[Table 2]

[0008]

However, the above-mentioned known examples have the following disadvantages.

Regarding a, if a very small amount flows, it cannot be detected as a gas leak, so that the gas may be continued to flow without shutting off the gas, resulting in a gas accident. Conversely, when a gas appliance that uses a high calorie gas amount has been used for a long time, the gas appliance may be determined to be a gas leak and shut off.

Regarding b, it is possible to make a determination to prevent a gas leak accident beforehand by changing the continuous use safety time in accordance with the gas usage. This does not mean that there is a high possibility of malfunction.

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

[0012]

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

[0013] In a gas leak detection method in which a gas appliance with a governor is attached to a terminal of a gas leak inspection section and the gas appliance is in use, a supply gas pressure fluctuation device is provided upstream of the gas leak inspection section. And in the gas leak inspection section, the supply gas pressure change
A gas pressure detection sensor and a flow rate detection sensor are mounted downstream of the moving device, and the supply gas pressure is actively fluctuated by the supply gas pressure fluctuation device. the variation respectively detected by the gas pressure detecting sensor and the gas flow rate detection sensor, a correlation was observed fluctuations in pressure and flow rate of the
In this case, a gas leak detection method for determining that there is a gas leak.

[0014]

When the gas supply pressure is actively changed by a gas meter having a mechanism for detecting a change in the gas supply pressure in addition to the gas flow rate, the change in the gas flow rate due to the change in the gas supply pressure is corrected on the instrument side. Without such a mechanism, fluctuations in the gas supply pressure directly cause fluctuations in the gas flow rate. The time of gas leakage corresponds to this case. Therefore, when a gas leak occurs, there is a correlation between the gas supply pressure and the gas flow rate.

On the other hand, gas water heaters, bath kettles and the like have a built-in gas governor in the appliance, and the gas governor absorbs fluctuations in the gas supply pressure. It does not appear. Therefore, the gas supply pressure and the gas flow rate have no correlation. The present invention detects a gas leak by focusing on a correlation between a gas supply pressure and a gas flow rate.

The gas supply pressure is actively varied, 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 operation circuit.
In the correlation calculation circuit, when the gas supply pressure is constant (however, a slight variation width is observed) and only the flow rate is changing, the correlation calculation is not performed, the gas supply pressure is changed, and the gas supply pressure is changed. If a correlation is found between the change and the change in gas flow rate, a signal is sent to a gas leak determination circuit (pressure fluctuation, flow rate fluctuation, correlation inference mechanism) to determine that there is gas leakage, and the gas leak is determined. If the circuit determines that there is a gas leak, the gas is shut off. Alternatively, a gas leak alarm is issued at the same time.

[0017]

FIG. 1 is a diagram for explaining an embodiment of the present invention. 1 is a gas meter (microcomputer meter),
The gas meter 1 includes a gas pressure detection sensor 2, a gas flow rate detection sensor 3, a gas shutoff valve 4, a correlation calculation circuit 5-1 and a gas leak determination circuit 5-2, and an active pressure fluctuation device (for example, a governor, a valve). Etc.) 10 are incorporated.
6 is a service pipe, 7 is an indoor pipe connecting the header 8 and the gas appliance 9 with a governor. The supply gas entering the gas meter 1 from the service pipe 6 is measured by the gas meter 1 and then the header 8 → indoor. It flows from the pipe 7 to the gas appliance 9.

The gas supply pressure is actively fluctuated 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 further detected by the gas pressure detection sensor 2. This detected value is calculated by the correlation operation circuit 5-
1 is input. In the correlation calculation circuit, when the gas supply pressure is constant (however, a slight variation width is observed) and only the flow rate is changing, the correlation calculation is not performed, the gas supply pressure is changed, and the gas supply pressure is changed. When a correlation is found between the change and the change in the gas flow rate, a signal is sent to the gas leak determination circuit 5-2 (pressure fluctuation, flow rate fluctuation, correlation inference mechanism) as gas leakage, and When the gas leak determination circuit determines that the gas is leaking, the gas is shut off. Alternatively, a gas leak alarm is issued at the same time.

FIG. 2 is a judgment 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 judge that the gas appliance is used and that no gas leakage has occurred. When the equipment using the gas is used for a long time, no erroneous shutoff occurs. If there is a correlation,
By inferring from pressure fluctuation, flow fluctuation, and the strength of the correlation, finer discrimination for gas leak determination can be performed. Further, since the fluctuation of the gas supply pressure is caused by the surrounding households using the gas, the period and magnitude of the fluctuation cannot be predicted depending on the surrounding environment. Therefore, by determining the period and magnitude of the gas supply pressure and actively fluctuating, the accuracy of gas leak estimation (correlation calculation accuracy, estimation accuracy in the arithmetic inference mechanism) is increased, and the calculation speed and calculation amount are increased. Is also reduced.

[Brief description of the 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]

 DESCRIPTION OF SYMBOLS 1 Gas meter 2 Gas pressure detection sensor 3 Gas flow detection sensor 4 Gas shutoff valve 5-1 Correlation calculation circuit 5-2 Gas leak judgment circuit 6 Serving pipe 7 Indoor piping 8 Header 9 Gas appliance 10 Active pressure fluctuation device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-24493 (JP, A) JP-A-4-50727 (JP, A) JP-B-4-10018 (JP, B2) (58) Field (Int.Cl. ⁷ , DB name) G01M 3/00-3/40 G01F 1/00 G01F 3/22 G08B 21/00

Claims (1)

(57) [Claims] 1. A method for detecting a gas leak when a gas appliance with a governor is attached to a terminal of a gas leak inspection section and the gas appliance is in use, the supply gas pressure is provided upstream of the gas leak inspection section. A fluctuation device is installed and the supply gas pressure fluctuation is within the gas leak inspection section.
A gas pressure detection sensor and a flow rate detection sensor are mounted downstream of the moving device, and the supply gas pressure is actively fluctuated by the supply gas pressure fluctuation device. the variation respectively detected by the gas pressure detecting sensor and the gas flow rate detection sensor, a correlation was observed fluctuations in pressure and flow rate of the
In this case, a gas leak detection method for determining that there is a gas leak.