GB705392A - Improvements relating to hypodermic injection apparatus - Google Patents

Abstract

705,392. Hypodermic injection devices. TURNBULL, F. M. March 14, 1951, No. 6202/51. Class 81(2) In a hypodermic injection assembly a tubular member has by-pass, means integral with its bore the surface of which supports a stopper sealing the by-pass against passage of liquid. In one form of the invention an ampoule tube 15, Fig. 1, is provided with a fixed stopper 18 at one end and a piston stopper 16 at the other end. The tube 15 is divided by a third stopper 20 into a liquid medicament chamber 22 and a liquid or powder medicament chamber 21. A' by-pass 23 in the form of a groove in the bore of the tube 15 is provided near the stopper 20. When it is desired to mix the medicaments in the chambers 21, 22 the piston stopper 16 is projected into the tube 15, pressure being transmitted through the liquid adjacent this stopper 16 to project the stopper 20 until it lies in the region of the by-pass grove 23. Continued projection of the piston stopper 16 will force liquid from the first medicament chamber 22 through the by-pass 23 into the second medicament chamber 21. When the two medicaments have been thoroughly mixed by agitation, they are drawn into a hypodermic syringe the needle of which punctures the fixed stopper 18. The by-pass may alternatively take the form of several straight or helical grooves in the bore of the ampoule tube 15 or the tube 15 may be made of oval cross-section in the region where a by-pass is required. Alternatively, the stopper normally sealing the by-pass may be made of resilient material and the by-pass may take the form of ribs constricting the bore of the ampoule tube, liquid being enabled to flow between the ribs when the stopper is pushed on to them. The ampoule may be used with a syringe having a thrust or post portion in which case the fixed stopper is replaced by a wall integral with the body of the ampoule Fig. 6 (not shown). The invention may be embodied in a syringe. The syringe barrel 39, Fig. 7, is provided with a piston stepper 44 at one end and a needle 40 fitted with a cover 46 at the other end. The barrel 39 is divided into two medicament chambers by a stopper 41, a by-pass 49 being provided. The needle cover 46 is removed and used to project the piston stopper 44 so that liquid in one medicament chamber 43 projects the stopper 41 and is thus enabled to flow through the by-pass 49 into the other medicament chamber. On further projection the piston stopper 44 bears against the stopper 41 and together the stoppers 41, 44 force liquid through the needle 40 for injection purposes. In another embodiment of the invention, Fig. 11, a syringe is provided having only cne medicament chamber 60. On projection of a piston stopper 57 by a needle cover 56, a stopper 58 which normally seals a by-pass 59 in the form of ribs or grooves in the bore of the syringe barrel 54, is moved so that liquid from the medicament chamber may be forced through the by-pass to the injection needle 55.