Patent ID: 7506658

Claim:
A liquid flow control device comprising: a housing having an annular inner wall extending between a first side wall and a second side wall, the inner wall forming an inner periphery, the first and second side walls extending radially outward from the inner wall to an outer periphery, the first and second side walls and the inner wall together defining an annular chamber, the housing having an inlet disposed at the inner periphery for passage of liquid into the chamber, the housing having an outlet in the outer periphery for passage of liquid out of the chamber; an annular block of water swellable material located in the chamber so as to encircle the inner wall; and a layer of sealing material encircling the annular block of water swellable material on the side thereof adjacent the inner periphery to seal with the inner periphery when the annular block of water swellable material is swollen through contact with the liquid as the liquid passes from the inlet to the outlet of the housing; wherein the inlet comprises a plurality of orifices in the inner periphery of the housing for liquid to flow into the housing and the outer periphery of the housing has an opening to permit release of the liquid from the housing when the inlet orifices are not closed by the annular block of water swellable material.