Method and apparatus for accurately dispensing liquids and solids

Abstract

A system for metering and dispensing single and plural component liquids and solids as described herein. The dispensing system has a microprocessor-based control system and volumetrically efficient non-reciprocating pumps which provide a very accurate control of component ratios, shot sizes, flow rates and dispense durations. The dispensing system maintains constant pressure between the output of the pump and the dispense head. The progressive cavity pump is formed from individual, interlocking pressure sections, each of which has a double helix bore. A dispense head for a plural pump dispensing system using sealed bellows with rods extending therethrough associated with an actuator. The sealed bellows attach at one end to the body of the dispense head and at the other to the rods. The rods extend into a chamber and have a sealing end selectively engaging the exits from the chamber. The dispense head may further incorporate an actuator controlling the rods, a controller controlling the pumps and the actuator to close down the system simultaneously and the pumps themselves. A static mixer may be used with the exits. The system also has numerous feedback components for accurately controlling the pressure, flow rates, fluid levels and amounts of fluids dispensed.