Intermixing syringe

Claim 1

An intermixing syringe for the isolated storage of at least two medicant portions and the like, the syringe including an outer housing having an open rear end and a partially closed front end with a passageway therethrough, and a hollow plunger carrying on its front end a piston slidable in the bore of the housing and in its hollow portion providing for the isolated storage of at least one of the stored medicant portiOns, the syringe including means whereby at least one of the medicant portions may be transferred from the hollow plunger to the housing for the mixing of the portions, the syringe having means for bringing the stored portion in the housing and the same housing portion into a condition of reduced pressure, the syringe comprising (a) an outer housing of generally tubular configuration having an inner bore of a generally constant crosssection, the housing having a front partially-closed end with a discharge passageway therethrough; (b) removable means for selectively closing the passageway of the partially-closed front end of the housing so as to prevent the passage therethrough of air, fluids and the like; (c) a hollow plunger of a closed construction and having a main portion of generally tubular configuration sized to easily move axially in the bore of said outer housing without sealing of the bore of the housing; (d) a front end of the plunger in which there is provided a reduced diameter portion of determined length terminating in a forward flange of a determined larger diameter; (e) an end wall provided at the forward end of the plunger said wall having a front aperture therethrough for the flow of fluid; (f) a tear-away seal member carried by the plunger and disposed to seal the aperture in the forward end wall of the plunger; (g) a resilient piston mounted and sliding on the reduced diameter portion of the forward end of the plunger, said piston having at least one forward ring-like sealing surface sized so as to be slidable in the bore of the housing while engaging said bore in a fluid-flow sealing manner, the piston having at least one flow passageway formed in its side wall with one end of the passageway open to the interior of the plunger and the other end terminating at the piston outer surface and rearwardly of a forward ring-like sealing surface, said piston further formed so that those ringlike sealing surfaces forward of the formed flow passageway are deflectable from a sealing condition to a fluid-flow forwardly condition permitting the fluid in the plunger to flow through said passageway and past the forward sealing surfaces and into the forward housing portion when said forward housing portion is brought to a condition of reduced pressure, said piston further having at least one ring-like sealing surface rearwardly of the flow passageway through the sidewall of the piston; (h) means on said outer housing engaging said piston upon rearward movement of the plunger in the housing whereby said piston actuates and tearaway seal member to uncover said forward aperture; (i) a rear aperture formed in the plunger near its rear end, and (j) a sealing means providing a tear-away seal adapted to close said rear aperture to provide a fluid-tight closure, said sealing means being readily removed from the aperture to uncover the aperture by manipulation of the syringe by the user.