| 摘要 |
PROBLEM TO BE SOLVED: To immediately stop a flow of gas even in the case of using other gas instrument at the time of leaking the gas. SOLUTION: Transmission of an ultrasonic wave is repeated between vibrators 11 and 12 obliquely installed at a channel 13, and a propagating time is measured by a propagating time measuring means 19 to obtain a flow rate. Meanwhile, a gas leakage signal is detected by a gas leakage detecting means 9, a gas leakage is decided, and whether a gas leakage detecting time flow rate is there or not or whether there is a gas flow or not after the gas leakage is detected is rapidly decided by a shut-off deciding means. When the presence of the gas flow and the using of a gas instrument are judged, a shut-off is output to a shut-off means 4.
|
