Blood filtration unit with manual vent means

Claim 1

In a blood transfusion filtration unit having a filter cartridge disposed within a housing the improvement comprising a manually operable air vent valve disposed in the upper portion of said housing said air vent valve comprising an actuating member, said member comprising a circular portion disposed on the outside of said housing, said circular portion having a resilient periphery in contact with the outside surface of said housing, a reduced diameter portion extending from the center of said circular portion through an opening in the housing and an expanded and portion disposed from said reduced diameter portion within the housing; and end portion functioning to provide a seal with the inside surface of said housing, an annular air filtration media disposed between the housing and the resilient periphery of said circular portion of said actuating member on the outside of the housing; said resilient periphery being deformed in response to manual pressure applied to said circular portion so as to bias said expanded end portion in such a manner as to break said seal and provide a continuous unobstructed flow path for air from within said housing, through said filtration media, to atmosphere.