Apparatus for dispensing a composition

An apparatus for dispensing a composition, the apparatus comprising:

• a barrel having an inlet and an outlet;
• a screw received in the barrel, the screw having a distal end and a shank end spaced along a longitudinal axis, and a shaft having a single helical flight disposed thereon, the shaft becoming progressively larger in diameter from the shank end to the distal end;
• and
• a drive mechanism operatively coupled to the shank end and capable of rotating the screw within the barrel,
• wherein the screw is hollow and includes one or more interior surfaces and one or more exterior surfaces, the one or more interior surfaces defining a cavity adjacent to the outlet, and wherein the screw further includes a plurality of apertures through which the cavity and the one or more exterior surfaces of the screw communicate with each other, and
• wherein the the single helical flight extend around the shaft, the helical flight including a raised flight section and one or more lowered flight sections adjacent to the raised flight section, and each of the one or more lowered flight sections located distal to the raised flight section and adjacent to an exposed surface of the shaft, and
• wherein the plurality of apertures are at least partially located on the one or more lowered flight sections, wherein the plurality of apertures are located on the helical flight,
• wherein the perforated portion defines a hole area, representing a total cross-sectional area of the apertures per unit area of the one or more exterior surfaces, that increases with the diameter of the shaft along the longitudinal axis and distance from the shank end.

An apparatus for dispensing a composition, the apparatus comprising:

• a barrel having an inlet and an outlet;
• a screw received in the barrel, the screw having a distal end and a shank end spaced along a longitudinal axis, the screw comprising a shaft having a single helical flight extending around the shaft, the shaft becoming progressively larger in diameter from the shank end to the distal end;
• and
• a drive mechanism operatively coupled to the shank end and capable of rotating the screw within the barrel,
• wherein the screw is hollow and includes one or more interior surfaces and one or more exterior surfaces, the one or more interior surfaces defining a cavity adjacent to the outlet, and wherein
• the screw further includes a plurality of apertures through which the cavity and the one or more exterior surfaces communicate with each other, and
• wherein the plurality of apertures are located along a perforated portion on the helical flight,
• wherein the perforated portion defines a hole area, representing a total cross-sectional area of the apertures per unit area of the one or more exterior surfaces, that increases with the diameter of the shaft along the longitudinal axis and the distance from the shank end.