Cartridge based fluid dispensing apparatus

摘要

A concentrated flavor dispensing machine having displacement pumps for delivering between a fraction of a milliliter and a few ounces of fluids having a viscosity value between 1 to 4000 centepoise is described. The dispensing machine includes a cabinet for containing a multitude of displacement pumps, where each displacement pump is realizably connected to a disposable pre-filled fluid cartridge. Each displacement pump includes a stepper motor in engagement with a threaded drive rod that is advanced or retracted by any one of several predetermined distances. The drive rod impels a plunger positioned within the disposable cartridge to dispense a volume of fluid. Flexible capillary tubes connected to the output of each disposable cartridge direct the fluid to a central dispensing area. The disposable cartridge includes an expandable plunger which draws fluid back into the cartridge when the drive rod is withdrawn after a dispense operation for drip prevention.

主权项

1. A pump unit for dispensing a predetermined volume of fluid comprising:
a stepper motor in threaded engagement with a threaded drive rod, the stepper motor rotatable in one direction by a number of steps to advance the threaded drive rod; a cartridge mount coupled to the stepper motor, the cartridge mount having a locking means with an aperture sized to pass the threaded drive rod; a disposable cartridge having a first end adapted to engage the locking means for securing the disposable cartridge to the cartridge mount, the disposable cartridge having a chamber sealed with a plunger slidable in the chamber, the disposable cartridge having an outlet nozzle at a second end for dispensing contents of the chamber when the plunger is pushed by the threaded drive rod, and the plunger including an expandable plunger top of resilient material deformable to an expanded state when the plunger is pushed by a piston connected to the threaded drive rod, the expandable plunger top returning to a relaxed state when the piston is withdrawn from the plunger by a predetermined distance.