Flow control device

Patent Granted A pressure type flow control device enabling a reduction in size and an installation cost by accurately controlling the flow of a fluid in a wide flow range. Specifically, the flow of the fluid flowing in an orifice (8) is calculated as Qc = KP1 (K is a proportionality factor) or Qc = KP2m(P1-P2)n (K is a proportionality factor and m and n are constants) by using a pressure P1 on the upstream side of the orifice and a pressure P2 on the downstream side of the orifice.