Dry Processing Technology: Focus on Powder and Bulk Operations
November 1, 2006
The golden nugget of efficiencyWhen it comes to the manufacture of its chicken nuggets, Unilever Ice Cream & Frozen Foods in Lowestoft, UK, periodically reassesses all of its manufacturing processes to identify areas where quality, efficiency and worker safety can be improved. In one such review, the plant discovered that redesigning the way its dry ingredients are transferred into the wet batter mix used to coat the chicken nuggets could improve operator comfort and safety, minimize product loss, cut dust emissions and boost process efficiencies.
In the manufacture of chicken nuggets, raw chicken is mixed with other ingredients and shaped prior to being coated. The nuggets are then cooked, quick-frozen and packed. While the in-line process involving the wet batter mix is continuous, preparation of the dry batter mix is an off-line batch process.
"Before we decided to install the bulk handling system, the process was very labor-intensive," says Martin Pavitt, Unilever's project engineer. Operators accessed a 1,874-lb. pallecon (a pallet-like container with sides) of dry batter mix, removed the lid to expose the plastic liner and moved the pallecon to a tipper with a forklift truck. Then, the pallecon's plastic liner bag spout was manually untied and placed into the neck of a chute for the powder to be discharged, filling two 150-lb. capacity bins mounted on a wheeled cart. A manually operated slide gate controlled the flow of material. Filled bins were then wheeled anywhere from 30 to 300 feet to batter mixers adjacent to chicken nugget coating lines.
To improve efficiency on the line, Unilever selected a Flexicon bulk handling system that consists of a low profile feed hopper with flow promotion devices, a 10-ft. model 1450 flexible screw conveyor and a 2-hp gear drive. The unit is mounted on a mobile base frame with adjustable leveling jacks. Two 35-cu.-ft. intermediate bins complete the system.
Now, the 1,874-lb. bulk bags are positioned using a remote controlled hoist, which offers more efficient transfer of the dry batter into the intermediate bins. Using the hoist, an operator suspends a bulk bag above one of the bins and unties the bag spout, allowing the contents of the bag to free flow into the bin, which is then transferred using a pallet jack to the appropriate process line. The transfer bins are equipped with flow promotion devices that continuously agitate the material to prevent packing, caking, smearing and bridging.
"Previously, our operators had to use a stainless steel shovel to manually transfer the dry batter mix from the mobile bins into a 5-ft. high hopper," says Pavitt. The new system eliminates shoveling because the intermediate bins are positioned directly above the low profile T-18 hopper and lowered to allow the outlet cone of the bin to seat against the hopper seal.
With the installation of the system on the chicken nugget line a success, the Lowestoft plant also adopted the system on four additional lines: crispy chicken, Bar-B-Q griddlers, waffle fries and another chicken nugget line. "By adding automation to this process, we've cut six hours of work down to one-and-a-half hours," says Pavitt.
For more information:
Dave Boger, Flexicon Corp.; 610-814-2400