Gas shut-off system

摘要

PCT No. PCT/JP84/00477 Sec. 371 Date Jun. 9, 1986 Sec. 102(e) Date Jun. 9, 1986 PCT Filed Oct. 11, 1984 PCT Pub. No. WO86/02431 PCT Pub. Date Apr. 24, 1986.This gas shut-off system includes a flow rate sensor (2) for detecting a gas flow rate and a control unit having a miocrocomputer (6) which determines abnormal states such as gas leak when a predetermined flow rate continuously keeps over a predetermined time period and automatically closes a shut-off valve (4) in accordance with the determination. A battery (13) is employed as a power-source for the microcomputer (16) and the shut-off valve (4). In order that the consumption amount of the battery (13) is reduced as small as possible, the microcomputer has a standby function and is set to the standby condition except gas flow rate computation and so on until the shut-off valve (4) is opened after set to the shut-off condition. An indicating device for indicating various states of the system comprises a light emitting diode (19) which is single indicator, so that power consumption is reduced.