GAS CUTOFF DEVICE

To provide a gas cutoff device capable of preventing erroneous determination as a leakage due to fluctuations in instantaneous flow rate due to pulsation or breathing phenomena.SOLUTION: The gas cutoff device is configured so as to accumulate at predetermined intervals the flow rate values calculated by a flow rate calculation unit 3 from the instantaneous flow rate measured by a flow rate measurement unit 2, and a flow rate existence/absence determination section 6 determines whether the flow rate exists/absent based on the result of a first determination unit 4 that determines whether the integrated flow rate value is equal to or higher than a predetermined flow rate and the result of a second determining unit 5, which determines whether the continuous time in which the integrated flow rate value of the first determining unit 4 is less than the predetermined flow rate is longer than the unit integration period.SELECTED DRAWING: Figure 1 【課題】 脈動や呼吸現象による瞬時流量の変動で漏洩と判定する誤判定を抑制できるガス遮断装置を提供する。【解決手段】 流量計測部２により計測した瞬時流量から流量演算部３により算出した流量値を所定間隔ごとに積算し、積算流量値が所定流量以上か否かを判定する第一判定部４の結果と、前記第一判定部４の積算流量値が所定流量未満である状態が連続する時間が単位積算期間以上か否かを判定する第二判定部５との結果に基づき、流量有無判定部６が流量なし或いは流量ありを判定する。【選択図】図１