Abstract: A valve for alternately interrupting and permitting fluid flow is comprised of a cylindrical valve body having medial inlet and outlet chambers which are interconnected by a flow restricting orifice. An inlet enters into the inlet chamber, which opens out of the lower end of the valve body, and an outlet enters into the outlet chamber, which opens out of the upper end of the valve body. A poppet, which slidably fits within the inlet chamber, translates between a closed position wherein it prevents fluid flow through the orifice and an open position wherein flow is permitted, but is normally biased to its closed position by a spring. A plunger, which slidably fits within the outlet cavity, has a reduced diameter extension which extends through the orifice into contact with the poppet so that depression of the plunger causes the poppet to be moved to its open position and, unless otherwise restrained, release of the plunger would cause the poppet to be moved to its closed position.