| 摘要 |
PURPOSE:To decrease a response time when there is a high flow rate, by a method wherein, by means of a comparing means, comparing a pressure in a piping with a pressure previously set in a pressure regulator, the integrating time of the regulator is switched to prevent the occurrence of hunting when there is a low flow rate. CONSTITUTION:When there is a low flow rate and water is stably fed, i.e., when a state of a set flow rate Qs > a process flow rate Qp is transferred to a state of a set flow rate Qs < a process flow rate Qp as a result of an amount of water used being increased, a flow rate is detected by a flow meter 6, and a signal therefrom is decided by a comparing circuit 11 of a PI constant switching circuit 9. If the Qs is less than the Qp, by means of a signal from the comparing circuit 11, a PI constant switching output circuit 12 outputs a switching instruction to a pressure regulator 8. In the pressure regulator 8, since, by means of an instruction from the PI constant switching circuit 9, a time of integrating control when the Qs is less than Qp is previously set, when a switching instruction is inputted, the time is switched. When there is a high flow rate, an integrating time is decreased and a response time is increased, and when there is a low flow rate, an integrating time is increased to prevent the occurrence of hunting phenomenon.
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