Patent ID: 8381755

Claim:
A corrosion resistant reference pressure type flow rate controller to be used for a pressure type flow rate control reference, comprising: (a) an orifice; (b) a control valve provided on the upstream side of the orifice; and (c) a computation control device wherein a flow rate Q is computed by Equation Q=KP 1 , wherein K is a constant, and a pressure P 1 is detected with a pressure detector, and the difference between a flow rate command signal Qs and the flow rate signal is made to be a control signal Qy that is outputted to a driving part of the control valve; wherein the pressure P 1 on the upstream side of the orifice is adjusted by opening or closing of the control valve when the pressure P 1 upstream of the orifice and a pressure P 2 downstream of the orifice are maintained below a critical pressure ratio of a fluid to be controlled, thus controlling the flow rate Q of the fluid downstream of the orifice, and wherein a gold-plated layer is formed on an inner fluid contacting part of the reference pressure type flow rate controller.