|How MPA Pumps Work
The Maguire standard Digital Controller provides the precise motor speed regulation and metering control necessary to assure absolute accuracy of color usage. Because metering rate is directly related to motor shaft rotation, accuracy is obtained by precisely controlling drive motor rotation.
The controller divides each full motor rotation into 106 increments, each increment representing a small fraction of a gram of color being carefully measured. The controller contains a 1/27 HP DC permanent magnet motor with variable speed control. In the standard configuration the motor is close-coupled to a heavy duty gearbox with a reduction ratio of 53:1.
As the motor turns, a "hall effect" pickup device on the motor send 2 pulses per revolution to the microprocessor. The gearbox ratio of 53:1 means that 106 pulses (2 x 53) are received for every single revolution of the motor shaft.
The digital counter located on the face of the controller provides the means for pre-determining the exact degree of pump head rotation and, therefore, the precise amount of color that will be added. To determine the proper setting for the counter, a simple formula is used based on percent of color required, a predetermined metering rate, and total shot weight in grams (or pounds per hour for extrusion applications).
Easy Maintenance and Cleaning
No part will wear out or need replacing. Occasional cleaning may be necessary. Pump tubes must be replaced periodically. Typical tube life is 1 to 6 months.
Cleaning is accomplished with soap and water. Disassembly is easy and parts are large. The unit must be free of liquid color contamination to operate properly.
The tube is laid into the slot across the top of the pump head running from front to back in a straight path across the top of the dowel pin rollers. With rollers turning, the tube is drawn under the edge of the housing overhang. Unlike 3-roller pump designs the clear cover disk need not be removed.