VISCOUS MATERIAL DISPENSER AND METHOD FOR DISPENSING

摘要

A reciprocating piston (136) with an integral valve (138) moves in a first direction with a cylinder (86) to pressurize viscous material contained therein, such as ice cream, thereby pushing it out of a dispensing nozzle (84) located at one end of the cylinder (86) while simultaneously extracting viscous material from a collapsible container (40) into the other end of the cylinder (86). When the piston (136) moves in a second direction, the integral valve (138) opens to allow the piston (136) to pass through the previously suctioned viscous material then within the cylinder (86). The dispensing nozzle (84) includes a normally closed, spring-biased valve (190) opened by the force of the pressurized material, closing of the valve (190) being assisted by a transient suction force occurring as the valved piston (136) begins to move in the second direction through the material. Suctioning the material from the collapsible container (40) is preferable when the material contains entrapped gas, as is the case with ice cream, since repeated compression of such containerized material can diminish its quality.