Patent ID: 6889875

Claim:
A metered-dose pump device for dispensing doses of a semi-solid substance, the device comprising: a substantially cylindrical body having a central axis and defining a chamber for housing the semi-solid substance; a dispensing mechanism coupled to one end of the body, the mechanism including a dip tube having an end with an orifice extending into the chamber along said central axis for extracting the semi-solid substance from the chamber; and a piston slidably coupled within the other end of the body, wherein the piston slides with sealable contact within said body, wherein said piston includes a central well which is positioned in line with said axis, said well having walls with a substantially conical shape and extending outwards from the bottom of the well relative to said axis, and wherein the bottom of the well is substantially the same size as the orifice of the dip tube, wherein as the dip tube enters the well the semi solid substance is able to flow down into the well around the end of the dip tube so as to facilitate extraction of the remaining semi-solid substance after a substantial portion of the semi-solid substance has already been extracted.