Cincinnati Milacron Inc.

Rangasami Sarat Chandra

Kirby Lee Stone

Apparatus is described for the controlled mixing of liquids in a predetermined ratio and is especially suitable for the dispensing of predetermined ratios of polyol and polyisocyanate liquids in the liquid injection molding of polyurethane articles. The ratio control is achieved by a master-slave velocity relationship between at least two metering pumps of the plunger or piston type which are velocity coupled and inject on a common programmed velocity profile that is fed into the pump control that is the master system. Each pump control system has a velocity feedback control loop (a closed loop system) and one signal into the slave automatic control system (typically the polyol system) is obtained in a suitable ratio from the feedback master automatic control system (typically the poly isocyanate system).

Ratio controlled mixing of liquids

Method for the controlled mixing of liquids in a predetermined ratio and is especially suitable for the dispensing of predetermined ratios of polyol and polyisocyanate liquids in the liquid injection molding of polyurethane articles. The ratio control is achieved by a master-slave relationship between at least two metering pumps of the plunger or piston type which are position coupled and inject on a common programmed velocity profile (in the master system), but with each system controlled by an automatic velocity feedback control loop (a closed loop system) wherein the reference signal into the slave automatic control system (typically the polyol system) is obtained in a suitable ratio from the master automatic control system (typically the polyisocyanate system). The method includes continuing to drive the metering pumps past the time that mixing is cut off.

Growing community of inventors

Cincinnati, OH, United States of America

Rangasami Sarat Chandra