PRESSURE-BASED FLOW RATE CONTROL DEVICE AND MALFUNCTION DETECTION METHOD THEREFOR

摘要

This pressure-based flow rate control device is provided with an orifice part which is provided in a flow path, an upstream pressure sensor which detects the fluid pressure upstream of the orifice part, a downstream pressure sensor which detects the fluid pressure downstream of the orifice part, a flow rate control valve which is provided in the flow path upstream of the upstream pressure sensor, and a calculation control circuit which controls the flow rate by controlling the flow rate control valve on the basis of values detected by the upstream pressure sensor and the downstream pressure sensor, wherein the calculation control circuit calculates the difference between values detected by the upstream pressure sensor and the downstream pressure sensor when no fluid flows through the flow path, and outputs a pressure sensor malfunction determination signal on the basis of the calculated difference.