Patent ID: 7753891

Claim:
A device comprising: a housing around a chamber; a piston having a first end, a second end, and a fluid passageway from the first end to the second end, the piston being insertable into the chamber; a valve associated with the fluid passageway such that flow through the fluid passageway is selectively regulated by the valve, the valve being disposed between the first and second ends of the piston at a position other than at the first or second end; and a piercing structure proximate the second end of the piston, the piercing structure comprising: a base portion having a first diameter; a head segment comprising a tip, the head segment having a beveled front surface comprising first and second solid bevel faces, and a back surface that joins the front surface at cutting edges; and a tube segment extending between the base portion and the head segment, the tube portion having a second diameter that is smaller than the first diameter and being more narrow than a widest position across the head segment, the piercing structure having an opening extending radially centrally through the base and a single opening extending through the front surface of the head segment at a point other than the tip at a position where the first and second solid bevel faces meet, the opening being in fluid communication with the fluid passageway.