METHOD AND APPARATUS FOR INHIBITING FLUID LOSS FROM A SYRINGE

摘要

The present invention is directed to syringes (8) that have needles (72) that retract after an injection to provide safe syringes which reduce the possibility of a sharps injury through retraction of the needle (72) after use into the barrel (40), a needle assembly (70) positioned in the hollow body (42), a fluid retention system positioned in the hollow body (42), and a plunger assembly (100) that moves in the hollow body (42). A fluid retention system retains in the syringe (8) any fluid remaining in the needle (72) after the plunger assembly (100) approaches tha distal end of the hollow body (42). The fluid retention system includes a variable volume vacuum cavity in fluid communication with the needle assembly (70) and providing a pressure drop in the needle (72), tending to draw into the hollow body (42) any fluid remaining in the needle (72).