A sequential stopper for hypodermic syringe

摘要

A sequential stopper (100) having structural features for facilitating substantially complete delivery of fluid held within a syringe barrel. The sequential stopper features a stopper body having a cylindrical side wall (102) proximal (104) and distal (106) ends, and one or more circumferentially-disposed sealing elements (110) thereabout. One (110b) of the circumferentially-disposed sealing elements may be located adjacent the proximal end (104) of the stopper body. An elongate hollow chamber (120) is disposed within the stopper body parallel to the longitudinal axis of the stopper body. A pair of longitudinal sealing elements (112) are disposed on the cylindrical side wall of the stopper body and are separated on the sidewall by a distance greater than a maximum width displayed by the elongate hollow chamber disposed within the stopper body. A recessed surface (114) is disposed between the longitudinal sealing elements adjacent the proximal end of the stopper body. In one embodiment, the recessed surface is formed as a sloping surface (114) extending obliquely from the proximal end of the stopper body towards the cylindrical side wall of the stopper body. A distally-directed conically-shaped projection (130) is located at the distal end (106) of the stopper body. The projection includes a wedge formed through a portion of the conically-shaped projection. Fluid force exerted on the proximal end of the stopper body will be directed towards the sloping surface (114). Continued fluid force will cause collapse of the cylindrical side wall in the area located between the longitudinal sealing elements, thereby establishing a fluid conduit between the proximal and distal ends of the stopper body. The distally-directed conically-shaped projection (130) prevents accumulation of fluid between the distal end of the stopper body and the internal shoulder located at the distal end of the syringe barrel, while the wedge permits fluid passing through the fluid conduit to exit the syringe barrel. <IMAGE> <IMAGE>