Diaphragm valves (or membrane valves) consists of a valve body with two or more ports, adiaphragm, and a “weir or saddle” or seat upon which the diaphragm closes the valve. …Diaphragm valves can be manual or automated.

In simple terms, the main purpose of a diaphragm solenoid valve is to control the flow of liquids and gases. Diaphragm solenoid valves have a rubber diaphragmthat moves up and down within the body of the valve, causing opening and closing against a hard seat.