Flow Control Valves

Abstract

Flow control valves are devices which control the rate of gas flow by manual adjustment of a variable orifice. Flow control valves should be capable of adjusting flow rates within the range of its associated flow-meter, assuming that the supply and delivery pressure are within normal limits. In order to achieve adjustment over the entire range of its associated flowmeter the valve should require more than 180° rotation. When in the closed position the flow control valve should not permit any gas to pass. Every flow control valve should be clearly identified as to which flowmeter it is associated. Moreover, identification should clearly and permanently indicate either by name or symbol the gas which it controls. Flow control valves used to adjust the flow rates of gases delivered to a vaporizer should clearly indicate this function.