Dispensing unit for a fluid dispensing machine, comprising a variable-volume pumping chamber, and machine comprising said dispensing unit

摘要

A dispensing unit for a fluid dispensing machine comprises at least an inlet duct (35) and an outlet duct (36) for fluid products, connected to a variable-volume pumping chamber (30) comprising at least one flexible wall (30a). Two non return valves mounted in counter-phase are located in the inlet and outlet ducts (35, 36), respectively. The pumping chamber is coupled to actuator means comprising a stepper motor (20) a screw-nut screw unit and a carriage (28). The carriage moves the pumping chamber from a zero position in which the chamber has a maximum volume to an upper limit in which the chamber has a minimum volume. An optic sensor (40) defines the zero point of the pumping chamber (30) so as to guarantee precision and repeatability of the dispensing operations.