MF Mass Flow Resin Control System

General Description

The MF System features Straight Tube Coriolis Mass Flow Meters that are the most reliable meter in the industry. The straight tube design operates undisturbed in hostile, vibration prone applications and has proven itself well suited for operation in a foundry environment.

The liquid portion of the MF is housed in a large, freestanding enclosure and is comprised of DC powered, magnetically coupled gear pumps in combination with the Coriolis Meters and air-actuated, three-way diverter valves. The pump runs in a recirculating format that provides constant chemical flow through the flow meters. During idle mixer time, the chemical flow is sent back to the storage containers. When required, the three-way valves instantly divert the chemicals to the mixing chamber, and then divert back to storage at the end of the mixing cycle.

The control portion of the standard MF is housed in a separate NEMA enclosure and consists of PID Process Controllers coupled with PWM DC Motor Control Boards. Based on flow signals from the Coriolis Meters, each PID controller regulates pump speed to maintain the desired setpoint. Any changes in liquid flow due to changes in viscosity, line restrictions, etc., are instantly compensated for. If, for some reason, the system cannot maintain the desired flow, low/high flow alarms indicate the problem to the operator.

Mass Flow Meters

The Coriolis Mass Flow Meters incorporate a number of innovative design features such as quiet mode oscillation, center balanced design, and unique straight tube design. These design features focus on maximizing a reliability and durability and minimizing vulnerability to measurement noise. These meters use thicker tube walls to eliminate mechanical fatigue due to sensor wear and stress due to vibration. All input and output signals are scanned and updated ten times per second.

These meters automatically adjust for material viscosity changes and minor line restrictions.

Resin Pumps

The two standard resin pumps are Tuthill™ brand external micro-gear design, and are magnetically coupled to ½-HP 90VDC permag motors. Magnetic coupling eliminates shaft seal and all associated maintenance issue with pump leakage.

Temperature Biasing

As a part of our standard Mass Flow PLC Control System, for systems set up for three part phenolic urethane, furan, or other coreactant controlled resin system, temperature biasing is standard. In addition to the normal PID control of pump speeds based on liquid viscosity changes, resin temperature, and the like, catalyst or coreactant speed is also varied based on sand temperature. For installations requiring a true fixed strip time this feature is invaluable. Temperature curve fitting parameters are user adjustable so that the system can be fine tuned to the exact chemical system being run. For best results, the thermocouple for sand temperature measurement should be located as close to the mixer inlet as is feasible in order to prevent lagging related problems.