Roll-over valve with underpressure security function

摘要

A roll-over vent valve (10) comprising a housing (12) formed with a fluid inlet (22) and a fluid outlet (18), a valve seating bounding an outlet aperture of the housing, a float member (26) received within the housing and axially displaceable between a sealed position wherein a sealing member (42) thereof sealingly bears against the valve seating (56) of the outlet aperture to seal the fluid outlet, and an open position wherein the sealing member (42) is disengaged from the valve seating (56) whereby the fluid outlet is in flow communication with the fluid inlet. There is further provided a pressure-retention device (34) extending intermediate the valve seating (56) and the fluid outlet, to thereby shut fluid flow therebetween as long as pressure differential between the fluid inlet and the fluid outlet does not exceed a minimal pressure threshold. The valve further comprises a one-way fluid inlet valve being in flow communication with said fluid outlet to allow fluid flow towards said fluid inlet a substantially high flow rate at the event of under-pressure at the fluid inlet.