Food Engineering

Sealed bulk transfer systems add capacity, flexibility

April 5, 2004
A dust-contained bulk bag unloading/filling/conveying system makes life easier for workers.

Flexible screw conveyor transports dextrose granules from bulk bag discharger to 500-lb capacity blender. Source: Flexicon.
Mother Murphy's Laboratories, Greensboro, N.C., manufactures more than 5,000 flavors and extracts for the bakery, beverage, cereal, prepared foods, and other segments of the food and beverage industry, as well as the tobacco and pharmaceutical industries. Sales have surged in recent years-so much so that roughly 500 of the products on its menu - principally dry blend powders containing maltodextrin - are run regularly on its processing lines.

Sales exceeded the capacity of the manual dumping and packaging equipment. Operators on two shifts had to work overtime to meet demand, emptying 50-pound bags of dextrose into a 500-pound capacity blender and adding spray-dried flavor bases. They bagged and boxed the blended products manually.

To relieve production pressure and add efficiencies, Mother Murphy's Laboratories added two bulk transfer systems featuring three bulk bag dischargers, two bulk bag fillers and five flexible screw conveyors manufactured by Flexicon.

Dextrose granules from 2000-pound bulk bags enter an 8-cubic-foot capacity hopper from a Flexicon BFC model bulk bag discharger with a cantilevered I-beam and hoist. Operators manually add spray-dried flavor bases from totes into the hopper. A Model 1800 flexible screw conveyor from Flexicon transports the dextrose and flavor base powders at a 45-degree incline to a blender capable of mixing 2,500 pounds of product in 15 minutes.

A second flexible screw conveyor moves the blended powders to the Flexicon Model BFL bulk bag filler, which fills 2,500-pound bags. The bags can move either to the warehouse or the packaging station.

The second transfer system moves powders from a second Flexicon BFC bulk bag discharger into a 500-pound capacity blender and then to a second BFL bulk bag filler with two flexible screw conveyors.

The packaging operation incorporates a third bulk bag discharger. A fifth flexible screw conveyor elevates the product and discharges it onto a vibratory conveyor containing a 30-mesh screen to sift and scalp foreign matter from product en route to two packaging machines.

Dust control was a critical consideration during system design. "It's a sealed system," explains Plant Manager John Worsley. It has cut down the dust problem in blending."

An iris flow control valve on the bulk bag dischargers enables the operator to cinch the spout before drawstring release. The valve can be opened gradually to control the rate of material discharge from the bag.

"A dust collector on the bag breaker takes care of the whole system," explains Worsley. The bulk-bag discharger's dumping station features a hood and dust-collecting vacuum that removes airborne dust from the atmosphere. Cartridge filters capture the dust. Reverse pulse/jet nozzles blast the filters, dropping the dust into the hopper.

Connecting areas are also carefully sealed. Transition adapters at hopper outlets contain dust at the connections to the fully enclosed flexible screw conveyors. The bulk bag fillers also utilize an inflatable rubber cuff that creates a dust-tight seal between the filler outlet and the bag spout interior.

Fresh sales continue to put pressure on production, but the worst days are over.

"We were getting to where we couldn't keep up 24/7," says Worsley. "With the new systems, we don't require nearly as much overtime from the workforce as before."

For more information:
David Boger, Flexicon Corp.
610-814-2400, ext. 663, sales@flexicon.com