Improvements in hypodermic syringes

Abstract

Abstract 871,854. Hypodermic syringes. FAURE, J. M. Oct. 27, 1959 [Oct. 27, 1958], No. 36392/59. Class 81 (2). A syringe ampoule 1 has two pistons 5, 6 joined by a rod 7 so as to provide a chamber 10 in which powdered medicament is stored and a second' chamber 9 which contains a liquid medicament or solvent for the powder. When it is to be used, a plunger is engaged with the recess 8 and the piston assembly is drawn back, so creating a partial vacuum in chamber 10, until the pistons 5, 6 reach by-pass recesses 11, 12, respectively. At this point air passes around piston 5 into chamber 9, so allowing the medicament therein to be drawn around piston 6 into the chamber 10. The closure cap 3 is then perforated by an injection needle. Modified arrangements described for admitting air to the upper chamber include an internal projection in the bore for deforming the plunger, a channel cut in the plunger stem where it passes through an otherwise sealed end-cap, a closure plug which is packed clear of the barrel by a projection on the plunger rod and a sealed diaphragm which is broken when the plunger is withdrawn.

Inventors

No inventors recorded.

Bibliographic Details