Improved needle-less parenteral fluid injector

Abstract

A fluid injector for use with a needle-less syringe or needle-less add-on IV line is disclosed. The injector is connected to a main IV line and has a fluid passageway from the syringe or the add-on IV set to the main IV line. The injector comprises an anti-backflow valve member where the member is movable under fluid pressure along between a first position where the fluid cannot flow through the injector and a second position where the fluid can flow through the injector. The member is a sinking type and has a specific gravity greater than 1.0. The injector also comprises a valve located near the syringe end of the injector for receiving the fluid from the syringe or the add-on IV line for injection into the main IV line and for automatically preventing air embolus entering into the IV line. The anti-air embolus valve comprises a piston in a conduit. The piston is movable between a first position and a second position. The piston has a central bore for the passage of the fluid, a capped end and an inlet end. An envelope surrounds the piston and is interior to the conduit, between the capped end and the inlet end. The anti-air embolus valve also has a stainless steel spring, surrounding the piston in the envelope to maintain the piston in the first position, where fluid and air cannot flow. An o-ring surrounds the piston at the capped end and forms a seal to prevent air and fliud flow through the injector in the first position.