As in order for aforementioned capacity control signal Qy to become null it squeezes making use of the fluid

摘要

PROBLEM TO BE SOLVED: To make opening of a downstream side valve of a throttle mechanism to be easily determined from a varying state of a flow rate output signal at operation time of a pressure type flow rate control apparatus since it is disadvantageous that an opening operation of the downstream side valve of the throttle mechanism cannot be determined by existence of the flow rate output signal on the mechanism in a conventional pressure type flow rate control apparatus.;SOLUTION: In the pressure type flow rate control apparatus, the downstream side valve of the throttle mechanism is made to be opened while a flow rate setting value Qe to be inputted into the pressure type flow rate control apparatus is made to be varied, and magnitude ΔV of variation of the flow rate output signal Qo from the pressure type control apparatus in which the flow rate setting value Qe being varied is to be detected. When the magnitude ΔV of variation of the flow rate output signal Qo is larger than a determined value, an opening operation of the downstream side valve of the throttle mechanism is to be determined as normal, while the opening operation is to be determined as abnormal when the magnitude ΔV of the variation is smaller than the predetermined value.;COPYRIGHT: (C)2008,JPO&INPIT