Abstract: A dry, disposable, low-cost nozzle assembly for a spring-powered medical injector power unit comprises a generally cylindrical molded plastic nozzle body which is removably attached to a medical injector module and it includes a longitudinal bore of a predetermined diameter and terminating in a conical segment short of the end surface thereof. A counterbore of a fine diameter is then formed between the apex and the end of the nozzle member, forming the ejector orifice. A seal member fits within the bore of the nozzle body and releasably attaches to the power unit's plunger. The seal member includes a conical tip dimensioned to fit with close tolerance in the conical segment of the body portion of the nozzle.

Abstract: An improved hypodermic jet injector system in which specifically designed adapters are used for joining conventional medicament supply vials to the hypodermic jet injector during the filling of the medicament chamber thereof whereby the valving structure may be greatly simplified and the ready substitution of one medicament for another facilitated such that there is no need to purge the injector device of the previously used medicament. The adapter comprises a relatively low-cost attachment for a medicament supply vial including a stopper-piercing needle having both a liquid passage and an air passage therein. The adapter also includes a hollow recess of a predetermined shape which has a stretchable membrane forming one wall thereof, the membrane having a zero diameter hole formed through it when the membrane is unstretched. The liquid passage of the piercing needle leads to the hollow recess.