Needleless hypodermic injection device

摘要

A needleless injection device has a housing containing a pilot valve connectable to a compressed gas source. A main valve is operatively connected to the pilot valve. The pilot valve and main valve form a two-stage valve with the pilot valve activatable to open the main valve utilizing gas pressure. Compressed gas in a reservoir flows through the open main valve to driven a plunger into an ampule to inject an injectant through a patient's skin.