GAS SHUT-OFF SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a gas shut-off system capable of preventing erroneous determination of inner tube leak.SOLUTION: The gas shut-off system includes: sectional computing means 8 that integrates the quantity of flow for a predetermined period of time and calculates an average quantity of flow in a section to acquire maximum quantity of flow and minimum quantity of flow; and flow determination means 9 that determines whether a gas flow exist or not from the sectional computing means 8. When the difference between the maximum quantity and the minimum quantity of the flow in the average quantity of the flow in the section is within a determination permission range and the average quantity of the flow Qt in the section is also within a determination permission range, the flow determination means 9 holds N differences in ascending order between the maximum quantity and the minimum quantity of the flow of the average quantity of the flow in the section. When the calculated average quantity of flow after a certain period of time has elapsed exceeds an average determination quantity of the flow, the flow determination means 9 determines that a gas leakage has occurred in the certain period of time.