Rolling diaphragm metering valve

Abstract

An improved metering valve, or flush valve, incorporates a rolling diaphragm mechanism of a cylindrical elastromeric material providing a smoothly transitioning flow rate control from the full open to the full close position. The rolling diaphragm sealing means is actuated by a floating cup driven by the differential pressure between the valve fluid inlet and an intermediate actuation control chamber. The valve control is spring biased to the normally closed position and is actuated by dumping all fluid from the control chamber through a poppet mechanism which is triggered mechanically through a sealing diaphragm. Upon dumping fluid from the metering chamber, the actuating cup is compressed by the pressure of the inlet fluids to roll the diaphragm to a substantially open position. A metering orifice within the actuating cup passes fluid from the inlet at a controlled rate to the metering chamber which, by the transfer of fluids through the metering orifice, is gradually filled with fluid and expands moving the rolling diaphragm towards the sealingly closed position. The amount of fluid passed is substantially a function of the size of the metering orifice. The metering orifice has a range in sizes. The design of the valve is such that the dynamic pressures across the rolling diaphragm are essentially in balance during actuation and closure, thus the closing bias can be established with a relatively weak spring mechanism or the like.

Dependencies are inferred from the claim text.