Parenteral fluid administration sets

Claim 1

A parenteral fluid administration set comprising a source of supply of the fluid to be administered, a flow regulator to which fluid flows through a flow line from said source by gravity, said flow regulator comprising an upright plastic-walled cylinder having top-and-bottom-end walls providing a regulator chamber, a normally open-ended overflow tube affixed to the bottom end-wall of the regulator chamber and extending uprightly therein, the upper end of said overflow tube determining the maxium level of fluid permitted to collect in the regulator chamber, a floating siphon including an annular float and a siphon U-tube disposed in and being movable vertically within said regulator chamber in accordance with fluid level therein, means for supplying fluid from said source to the regulator chamber thereby to provide therein a body of fluid on which the float is adapted to float, said siphon U-tube being affixed to the float so as to be movable in unison therewith, the shorter leg of the siphon extending downwardly through the float and having its end open to the fluid body below the float, the longer leg of the siphon extending downwardly through the bore of said upright over-flow tube and having affixed thereto at a predetermined position along its length which normally is well above the open-top of the overflow tube a disc-form valve element which is adapted to lower against and seat on said open top of the overflow tube thereby to close said overflow tube to downward-outward air flow therethrough responsive to manually induced build-up of air pressure within said regulator chamber, said presure build-up also functioning to prime the siphon.