Abstract: An apparatus for controlling liquid flow wherein the apparatus comprises an orifice and an adjacent flexible diaphragm separated from each other by a gap through which a liquid flows. The diaphragm is sufficiently flexible to vary the gap thereby controlling the rate of liquid flowing through the orifice or to provide a positive liquid shutoff of liquid flowing through the orifice. A method for controlling liquid flow through the apparatus comprises flexing said diaphragm to vary a size of the gap to control the rate of liquid flowing through the orifice or to provide a positive liquid shutoff of liquid from flowing through the orifice.