Abstract: A body having a channel therein in which a flow valve is movably mounted. An inlet communicating with the channel near one end thereof, and an outlet communicating with the channel spaced from said inlet. The flow valve has a head near the end of the channel in communication with the inlet and adapted normally to engage a seat in the channel to close the latter, a stem of smaller cross section that the head, and a guide portion remote from the head and slidably fitting in the channel. Means for moving the valve to move the head thereof off the seat to permit water to flow from the inlet past the head to the outlet, said water gradually moving the head back on the seat.