Automatic venting apparatus

摘要

Automatic venting apparatus for venting gas from a system containing a liquid, comprising; a body (1) having an inlet (12) and an outlet (16), with a passageway therebetween for venting gas received at the inlet through the body to the outlet; valve means located in the passageway between the inlet and the outlet, the valve means comprising a hygroscopic material (2) and being moveable between a first configuration in which the passageway is closed and a second configuration in which the passageway is open, with movement from the second configuration to the first configuration occurring when the hygroscopic material (2) expands upon contact with liquid; wherein the valve means further comprises a substantially water-impermeable valve member (3) located in the passageway between the inlet (12) and the hygroscopic material (2), the valve member (3) being moveable with the hygroscopic material (2) and configured to engage a valve seat formed in the passageway when the valve means is in the first configuration.