a sprinkler or water circulating system having a selected number of sprinkler heads , bubblers or the like , each having an associated valve mechanism adapted to effect valve closure upon displacement of the sprinkler head , bubbler , etc ., during water flow thereby preventing loss of sprinkler effect and fluid . a normally open spring loaded valve is positioned in a conduit to which the sprinkler head or the like is attached . a stem or rod is positioned in engagement between sprinkler head and valve so that upon displacement the stem may be broken off if of frangible material , or otherwise displaced and the valve is urged into closed position . upon replacement of the sprinkler head or the like in proper position the rod is replaced to maintain the valve in open position .