Patent ID: 8726924

Claim:
A flow-control valve comprising: a housing extending along an axis and having first and second input ports and respective first and second output ports for respective first and second separate fluid streams and formed between the first input port and first output port with a first valve seat having an axially throughgoing cylindrical hole and between the second input port and second output port with a second valve seat offset axially from the first valve seat; respective first and second valve bodies axially shiftable between positions blocking and unblocking the respective valve seats, the first valve body being a stem extending axially through the cylindrical hole of the first valve seat and having a portion with a frustoconical outer surface centered on the axis and axially thereadjacent a portion with a cylindrical outer surface that is also centered on the axis and that is a snug fit in the hole, whereby a flow cross section of the first valve seat is varied when the frustoconical surface is in the hole by an axial position of the stem and the first valve seat is blocked when the cylindrical surface engages in the hole; a coupling element connected axially between the valve bodies for joint movement of the valve bodies; and a diaphragm connected between the first valve body and the housing and defining between the diaphragm and the first valve seat an axially inner compartment into which the first input port opens and between the diaphragm and the housing an axially outer compartment, the stem of the first valve body being formed with a passage extending through the first valve body and having an axially extending part opening into the outer compartment and a transversely extending part opening into the an outer compartment of the housing between the first valve seat and the first output port.