FLOW-RATE CONTROL VALVE AND MANUFACTURE THEREOF

摘要

PURPOSE: To obtain a flow control valve for chemical substance fluid being employed in a case where prevension of contamination is essential. CONSTITUTION: The flow control valve has a flow control chamber 10 partitioned by a membrane operating member 26 made of a metal doil into an analyzing section and a driving section. The membrane operating member is held between the circumferential rim 18 of the flow control chamber and an upper wall 12 and moves between open and close positions in response to the pressure of a driving fluid. Upper part of the rim engaging the membrane and having relatively small surface area is made of a material softer than the material composing the membrane and the upper wall and constitutes means for sealing the circumferential part of the membrane with respect to the upper wall when it is fastened tightly. The membrane is shaped into a dome in the field by acting the fluid pressure to the flow control chamber through a port thereby deforming a flat metal foil being held tightly at a specified position in the chamber.