A customer needed to accurately measure the mass flow rate of snack food chips from a cooler, in order to ratio control the amount of seasoning applied to the chips. The chips were to discharge from a vibratory conveyor, flow through a mass flow measurement system, and then proceed to the seasoning tumbler where the seasoning was to be applied. They needed the meter to be able to output an instantaneous and accurate signal that could be used to control the seasoning feeder system. It was also critical to have a compact mass flow measurement system, due to space constraints, and to have an easy to clean, food grade measurement system. The average density of the chips was 4 lb/ft3 (64 kg/m3) with a maximum flow rate of 2500 lb/hr (1134 kg/hr) and a minimum flow rate of 300 lb/hr (136 kg/hr). Therefore, the flow meter needed to be capable of handling and accurately measuring a volumetric capacity from 75 to 625 ft3/hr. Besides providing an output to a controller, the meter needed to have a local display Indicating flow rate, total throughput per shift, and the total throughput per week.
THE SOLUTION FROM EASTERN INSTRUMENTS
The customer installed a CentriFlow Meter. The unit selected for installation between the vibratory conveyor and the seasoning tumbler was a 12” Type I CentriFlow Meter, installed in the In-Line Flow configuration at a 20o installation angle. An In-Line Flow transition was fabricated to convey product from the vibratory conveyor to the meter for weighing. The averaging analog 4-20mA output from the Ratemeter/Totalizer provided a mass flow rate to the PLC (proportional to the flow rate). This signal allowed the PLC to control the flow rate of the seasoning, the flow rate of chips entering the tumbler, even the rate of the tumbler itself, allowing the customer to correctly ratio seasoning to the chips, as well as to determine the totalization of the throughput of the process.
CONCLUSIONS
Once the CentriFlow Meter was installed, the unit was calibrated within hours and the seasoning system operated successfully. The meter’s output provided a much more accurate ratio of chips to seasoning, thus saving the customer by reducing waste. After having used weigh-belts in the past, the customer was pleased with using the CentriFlow Meter due to the cleanliness, ease of calibration, and no “zero” drift.
MATERIAL TEST REPORTS
The CentriFlow Meter can be used to measure finished products such as potato chips, tortilla chips or processed nuts in order to properly season them. The CentriFlow Meter has also been installed in blending applications where multiple products are blended together to manufacture snack mixes.
