JPH0631403Y2 - Gas leak detector for buried piping - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a gas leakage detection device for a buried pipe, which detects a gas leak caused by a buried gas pipe buried underground.

[Conventional technology]

Gas leak accidents in household gas pipes often occur especially due to corrosion of underground pipes in the ground, etc.As a preventive measure, in the past, security officers of gas companies were supposed to reduce gas usage late at night. From a visual check, the gas meter 15 in the pipeline shown in FIG. 2 was checked to determine the leakage of the buried pipe 5.

In FIG. 2, 1 is an LP gas cylinder, 7 is a gas pipe, 12 is a gas appliance, 13 is an automatic switching regulator, 14 is a pressure regulator, and the desired LP gas cylinder 1 is selected by the automatic switching regulator 13. LP gas is supplied from the selected cylinder 1. The supplied LP gas is adjusted to a predetermined gas pressure by the pressure regulator 14, introduced into the buried pipe 5 buried in the ground, and reaches the pipe end 9 via the gas meter 15 and the gas pipe 7. A gas appliance 1 is provided at each pipe end 9.
2 is connected and consumes LP gas. The gas meter 15 is for calculating the LP gas flow rate per unit time.

In addition, underground drilling near the buried pipe 5 was performed about once every two years to check with a gas leak detector.

[Problems to be solved by the device]

However, the above-described method for confirming gas leakage has a drawback that it is difficult to grasp a minute flow rate while manpower is required, and the certainty of gas leakage determination is lacking, and the latter method requires a large amount of work. In addition, the gas supply must be stopped during the work, which is annoying to the user.

Therefore, an object of the present invention is to provide a gas leak detection device for a buried pipe, which can reliably detect a gas leak in the buried pipe and can constantly monitor the gas without stopping the gas supply.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, a gas leakage detection device for a buried pipe according to the present invention is provided with a first gas meter for calculating a gas flow rate of a supply gas per unit time, and a first gas meter provided in parallel with the first gas meter. A second gas meter for calculating a minute gas flow rate per unit time of gas, a first switching means for switching the gas supply to the first and second gas meters, and the first or the first buried means buried in the ground. A small gas flow rate per unit time is calculated by branching to a gas pipe connected between a buried pipe through which the supply gas is introduced through the second gas meter and a pipe end to which a gas appliance is connected. A third gas meter, a second switching means for switching the supply of the gas derived from the buried pipe to the third gas meter and the gas pipe, and each calculated by the second and third gas meters A comparing means for comparing small gas flow rates, and the comparing means detects gas leakage from the buried pipe when the minute gas flow rate of the second gas meter is larger than the minute gas flow rate of the third gas meter. It is characterized by doing so.

[Action]

In the above configuration, in a normal gas usage state where a gas appliance at the end of the pipe is used, the first and second switching means do not directly pass the first gas meter and the third gas meter to the gas supply passage, Switched to the piping side. The supply gas is then led to the end through the first gas meter, the buried pipe and the gas pipe. On the other hand, when detecting gas leakage, the first and second switching means are set to the second and third switching means.
Switch to the gas meter side.

Therefore, the supply gas is the second gas meter, the buried pipe, the third
It is led out to the end of the pipe through the gas meter. Therefore, the comparison means compares the minute gas flow rates calculated by the second and third gas meters, and when the former gas flow rate is larger than the latter gas flow rate, determines that gas leakage has occurred from the buried pipe.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a piping diagram showing an embodiment of a gas leakage detection device for a buried pipe according to the present invention. In FIG. 1, the same parts as those in FIG. The gas passes through the pressure regulator 14 to the first flow path switching valve 2
Is supplied to. First and second gas meters 3 and 4 are provided in parallel on the secondary side of the first flow path switching valve 2. The gas from each gas meter 3 or 4 is introduced into a buried pipe 5 buried in the ground, and is supplied to a second flow path switching valve 6. A gas pipe 7 is connected between the secondary side of the second flow path switching valve 6 and the pipe end 9, and a third gas meter 8 is further branched to the gas pipe 7. The gas flow rates calculated by the second and third gas meters 4 and 8 are input to the comparator 10, and the output of the comparator 10 is output by the transmission device 1.
1 and the transmission line 1 to the gas supply company.

The first gas meter 3 of the above gas meters is for calculating the gas flow rate per unit time, that is, the gas flow rate when the gas appliance 12 is used as in the normal time of the day, and the second and third gas meters. 4 and 8 are gas appliances for nighttime use 1
It is used when gas leakage of the buried pipe 5 is detected when the frequency of use of 2 is low. Therefore, the gas flow rate per unit time that can be calculated by the second and third gas meters 4 and 8 is very small and smaller than the gas flow rate per unit time that can be calculated by the first gas meter 3. That is, the gas flow rate calculation accuracy of the second and third gas meters 4 and 8 is set to be higher than the calculation accuracy of the first gas meter 3.

In addition, a gas meter 16 is provided for each gas terminal 9 in the gas piping 7.
The gas meter 16 monitors the amount of gas used in the gas appliance 12 connected thereto and the gas leakage in the gas pipe 7 and the pipe terminal 9.

In the above-mentioned configuration, in a time zone in which gas is frequently used, such as daytime, the first and second flow path switching valves 2 and 6 are switched to the first gas meter 3 and the gas pipe 7 side, respectively. No gas is supplied to the third gas meters 4 and 8. Therefore, the LP gas from the gas cylinder 1 passes through the pressure regulator 14, the first flow path switching valve 2, the first gas meter 3, the buried pipe 5, the second flow path switching valve 6, the gas pipe 7, and the gas meter 16. In the gas appliance 12 connected to the pipe end 9, the L is introduced to the pipe end 9.
P gas can be used.

On the other hand, the first and second flow path switching valves 2 and 6 are switched to the second and third gas meters 4 and 8 side, respectively, in a time zone such as nighttime and late night when the gas usage frequency is low, and the first gas meter 3 LP gas is not supplied to. Therefore, the LP gas from the gas cylinder 1 is supplied with the pressure regulator 14, the first flow path switching valve 2, the second gas meter 4, the buried pipe 5, the second flow path switching valve 6, the third gas meter 8, the gas piping. 7. The gas is led to the end 9 of the pipe through the gas meter 16.

At this time, the gas appliance 12 is not used at all,
The gas flow rate flowing through the gas supply path from the gas cylinder 1 to the pipe end 9 is smaller than that in the daytime. Therefore, the second and third gas meters 4 and 8 calculate minute gas flow rates on the primary side (gas cylinder 1 side) and the secondary side (pipe end 9 side) of the buried pipe 5 and compare the gas flow rates with a comparator. Enter in 10. The comparator 10 compares the gas flow rates, and when the gas flow rate of the third gas meter 8 is greater than or equal to the gas flow rate of the second gas meter 4, no gas leakage has occurred and it is in a normal state. to decide. On the other hand, when the gas flow rate of the second gas meter 4 is larger than the gas flow rate of the third gas meter 8, it is judged that gas leakage has occurred from the buried pipe 5, and the gas supply company is notified via the transmission device 11 and the transmission line l. It gives a report or lights an alarm lamp (not shown). Thus, it is possible to constantly monitor the presence or absence of gas leakage without stopping the supply of gas and issue an alarm if necessary.

〔effect〕

As described above, according to the invention, it is possible to detect the gas leak of the buried pipe at any time early and surely without stopping the gas supply, and thus it is possible to prevent an accident due to the gas leak.

Further, since the patrol inspection at midnight is not required, the burden on the security personnel is reduced, and the buried pipe can be inspected without stopping the gas supply, so that the burden on the user is eliminated.

[Brief description of drawings]

FIG. 1 is a pipeline diagram showing an embodiment of a gas leakage detecting device for a buried pipeline according to the present invention, and FIG. 2 is a pipeline diagram showing a conventional gas pipeline. 1 ... LP gas cylinder, 2 ... first flow path switching valve, 3 ...
… First gas meter, 4 …… Second gas meter, 5 ……
Buried pipe, 6 ... second flow path switching valve, 7 ... gas pipe,
8 ... Third gas meter, 9 ... Piping end, 10 ... Comparator, 11 ... Transmission device, 12 ... Gas appliance, 13 ...
Automatic switching regulator, 14 ... Pressure regulator.

Claims (1)

[Scope of utility model registration request] 1. A first gas meter for calculating a gas flow rate of a supply gas per unit time, and a second gas meter provided in parallel with the first gas meter for calculating a minute gas flow rate of the supply gas per unit time. A gas meter, a first switching means for switching the gas supply to the first and second gas meters, and an embedded pipe which is buried in the ground and into which the supply gas introduced through the first or second gas meter is introduced. A gas pipe connected to the end of the pipe to which the gas appliance is connected is branched and provided to calculate a minute gas flow rate per unit time.
Gas meter, second switching means for switching the supply of the gas derived from the buried pipe to the third gas meter and gas pipe, and the minute gas flow rates calculated by the second and third gas meters. Comparing means for comparing, and when the minute gas flow rate of the second gas meter is larger than the minute gas flow rate of the third gas meter by the comparing means,
A gas leak detection device for a buried pipe, wherein a gas leak from the buried pipe is detected.