| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas cut-off method, and a gas cut-off device capable of reducing a frequency of incorrect determination of abnormal flow rate. SOLUTION: The gas cut-off device is provided with a flow rate monitoring part 1 monitoring a flow rate of gas flowing in a gas passage, a data operation part 2 calculating a momentary flow rate and a moving average flow rate on the basis of a detection output from the flow rate monitoring part, a data storing part 3 storing each data of the momentary flow rate and the moving average flow rate, a cut-off value storing part 4 storing a preset first cut-off value, and a second cut-off value preset larger than the first cut-off value, a data comparison part 5 comparing the moving average flow rate with the first cut-off value, generating an abnormal detection output when the moving average flow rate is larger than the first cut-off value, comparing the momentary flow rate with the second cut-off value, and generating an abnormal detection output when the momentary flow rate consecutively exceeds the second cut-off value a specific number of times which is a plurality of times, a control part 6 outputting a cut-off signal in response to the abnormal detection output from the data comparison part, and a cut-off part 7 controlled by the cut-off signal from the control part to cut off the gas passage. COPYRIGHT: (C)2005,JPO&NCIPI
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