Syringe filter and valve combination

Claim 1

A syringe having a barrel and a plunger slidable therein, said barrel having a cylindrical bore and having a bottom wall provided with an axially and downwardly projecting neck portion for rigid attachment to an injection needle, said neck portion having an axial flow passage communicating with said bore, wherein the improvement comprises an annular filter element fixed within said bore adjacent said bottom wall, said filter element being formed from foraminous material capable of filtering objectionable particulate matter from injectable fluids, said filter element having a central opening extending therethrough, and a tubular valve body secured within said central opening having an axial valve passage and having a normally-closed one-way valve closure element disposed at the upper end of said valve passage and spaced a substantial distance upwardly from said neck portion, said closure element being flexible between an open position and a normal closed position, and means bracing said closure element in said closed position and preventing movement of said closure element into said open position in response to greater fluid pressures above said filter element than below the same, whereby, said closure element and said bracing means cooperate to block downward flow through said passage when said plunger is urged downwardly and to permit upward flow through said passage when said plunger is raised.