Patent ID: 8386084

Claim:
A gas shutoff device for monitoring use statuses of a plurality of gas appliances connected to a pipe provided by being passed through a gas meter, and shutting the supply of gas when an error occurs, comprising: a flow measurement unit for measuring an amount of gas passing through; an individual appliance calculation unit for calculating a change in individual flow rate of an appliance among the plurality of gas appliances based on a flow signal of the flow measurement unit and outputting the calculated change in individual flow rate of the appliance; an individual appliance registration maintenance unit for outputting a maximum individual flow signal output from the individual appliance calculation unit; an abnormal flow determination unit for determining an abnormal flow rate from the individual appliance registration maintenance unit; and a notification unit for giving a warning notification of an error upon receiving an error signal from the abnormal flow determination unit or a shutoff unit for shutting a gas passageway, wherein the individual appliance registration maintenance unit includes a registration unit and a maintenance unit, wherein the individual appliance registration maintenance unit registers flow rates in the registration unit when an individual calculation flow rate output from the individual appliance calculation unit is an increased flow rate, and deletes an individual calculation flow rate that is regarded as the same after being compared with the registration flow rates from the registration unit and at the same time, registers the deleted flow rates in the maintenance unit when the individual calculation flow rate output from the individual appliance calculation unit is a decreased flow rate.