| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas shut-off device that prevents the erroneous determination of inner tube leakage.SOLUTION: A gas shut-off device comprises: section calculation means 7 that calculates a section average flow rate at a first prescribed section; moving average flow rate calculation means 8 that calculates a moving average flow rate from section average flow rates of N consecutive sections; third determination means 10 that determines whether difference between the maximum value and minimum value of a moving average flow rate at a second prescribed section is less than a threshold value or not; first determination means 12 that determines whether the section average flow rate is within a first prescribed rage or not; second determination means 13 that determines whether difference between the maximum value and minimum value in the first prescribed section is within a second prescribed range or not; relevant flow rate accumulation means 14 that accumulates a section average flow rate which is determined to be within the first prescribed range by the first determination means 12 and determined to be within the second prescribed range by the second determination means 13. If the relevant flow rate accumulation means 14 has accumulated M section average flow rates, the gas shut-off device calculates an accumulation average flow rate from the accumulated section average flow rates, and determines there is no flow rate if the accumulation average flow rate is less than an average determination flow rate.SELECTED DRAWING: Figure 1 |
