| 摘要 |
PROBLEM TO BE SOLVED: To surely detect both when a flow rate is higher than a normal flow rate and when the flow rate is lower than the normal flow rate by setting an upper limit stopper and a lower limit stopper for regulating an upper limit position and a lower limit position of a float in a taper tube and detecting that the float is at the upper limit position or lower limit position. SOLUTION: When a flow rate of a fluid running in a taper tube 2 is not larger than a lower limit of a normal flow rate, a float 3 hits a lower limit stopper 5 to stop, and therefore it is detected that the flow rate is not larger than the lower limit from a signal of a lower limit detection means 8. When the flow rate is not smaller than an upper limit of the normal flow rate, the float 3 is raised by a force of the fluid, hitting an upper limit stopper 4 to stop, whereby it is detected that the flow rate is not smaller than the upper limit from a signal of an upper limit detection means 7. When the flow rate is within a normal flow rate range, the float 3 floats in the halfway between the upper limit stopper 4 and the lower limit stopper 5, and neither the lower limit detection means 5 nor the upper limit detection means 4 detects the float 3. Accordingly, it can be detected that the flow rate is within the normal range. |
