Patent ID: 7125520

Claim:
A pump module for a liquid dispensing system comprising: a chambered block having a liquid chamber, an inlet port in fluid communication with said liquid chamber and a discharge port in fluid communication with said liquid chamber, said inlet port being radially spaced from said discharge port; a piston drive assembly having a piston, said piston being rotatably and translationally supported in said liquid chamber of said chambered block and including a relieved portion; a first motor mechanically coupled to said piston drive assembly for rotating said piston between a first position wherein said relieved portion of said piston is aligned with said inlet port of said chambered block and a second position wherein said relieved portion of said piston is aligned with said discharge port of said chambered block; and a second motor mechanically coupled to said piston drive assembly for axially translating said piston within said liquid chamber of said chambered block independent of said first motor, wherein said piston is able to be rotated and translated both independently and simultaneously, and wherein said second motor is able to operate at both equal and different rates with respect to said first motor.