Improvements in or relating to liquid flow control devices

摘要

The disclosure relates to a liquid flow control device comprising an annular housing (15) having an inlet (18) for liquid in one periphery of the housing and an outlet for liquid in the other periphery. An annular block of water swellable material (19) is located in the housing and a layer (20) of sealing material encircles the annular block on the side thereof adjacent the inlet (18) to close the inlet when the block is swollen through contact with the liquid.