Patent ID: 6886717

Claim:
A colorant pump module for pumping colorant, said module comprising: a bracket; a precision controlled stepper motor attached to said bracket; a pump, also mounted on said bracket and directly coupled to said stepper motor, said pump having a torque driving requirements sufficiently low such that said pump can be turned manually, wherein said stepper motor is directly coupled with said pump through a zero backlash coupling and wherein said pump comprises: a pump body having inlet tubing and outlet tubing connected thereto through which the colorant enters and exits said pump; wherein said outlet tubing can withstand high pressures without deforming; twin impellers with each impeller having an impeller shaft rotatable by said stepper motor; one set of precision needle bearings attached to the impeller shaft of said each impeller; twin cartridges seals attached to each impeller shaft; a precision machined pump chamber having pump chamber surfaces, which houses said twin impellers, wherein the pump chamber surfaces of said pump chamber is coated with a hard coat; and wherein the colorant is precision metered by said pump.