Patent ID: 7378058

Claim:
A fluid dispenser comprising: a barrel having a reservoir chamber including an upper portion and a lower portion; a coupler having a dispense chamber which is substantially in line with the reservoir chamber; a piston associated with the barrel lower portion and located between the reservoir chamber and the dispense chamber, the piston having an outer diameter and an inner diameter through which fluid is passaged, the piston being movable from an up-most to a lower-most position; a plug located within the piston fluid passage and including a plug stem attached to a shoulder having a bottom surface, the plug stem including at least one axial ridge and at least one radial ridge; a radial flow passage defined by the plug and the inside diameter of the piston and extending from the piston fluid passage to the piston outer diameter; and a sealing surface for sealing the piston fluid passage against fluid flow when the sealing surface is in contact with the plug bottom surface, wherein the plug bottom surface contacts the sealing surface when the piston is in the lower-most position.