A customer needed to accurately measure the mass flow rate of animal feed pellets from an extruder to apply the correct ratio of liquid nutrients. The animal feed was to discharge from an extruder, into a screw conveyor, through a mass flow measurement system, and then proceed to the mixing screw conveyor where the nutrients were to be applied.

They needed the meter to be able to output an instantaneous and accurate flow signal that could be used to control the nutrient injection system. It was also critical to have a compact mass flow measurement system due to the meter being installed in an existing process.  The average density of the dry, pet food was 40 lb/ft³ (641 kg/m³) with a maximum flow rate of 22,000 lb/hr and a minimum flow rate of 6,600 lb/hr. This meant that the flow meter needed to be capable of handling and accurately measuring a volumetric capacity from 165-550 ft³/hr.

Besides providing an output to a controller, the meter needed to have a local display that would indicate flow rate, total throughput per shift, and the total throughput per week.  Read on to find out more.