Utility Menu

Powder/Bulk Solids

The Source for Dry Processing and Bulk Handling Technology

Bulk Bag Discharger Allows Dual Conveying Applications to Meet Exact Packing Specifications

December 5, 2007
At GEM Pack Foods, a Type 6 Spiroflow bulk bag discharger and two Spiroflow flexible-screw conveyors deliver food product at a metered rate to a Fawema packing machine.

Adhering to the most exacting standards, Gem Pack Foods manufactures, warehouses, and distributes food products to most of the major food wholesalers and large supermarket chains in Ireland. It exports the remaining product overseas.

In its operations, the Dublin-headquartered company processes about 350 tons of sugar a week, along with large quantities of rice and corn flour to produce an extensive range of Gem and Gem Gourmet brand products. The sugar comes in various forms, ranging from granulated to fine icing grades. Gem Pack Foods uses bulk supplies to create several branded products, while other brand-name products are proprietary mixes. The company also serves as a contract packer for other companies.

A Fawema packing machine with two feed points is used by Gem Pack Foods to package the product in a wide variety of sizes ranging from 6.5-lb in-box bags down to single-portion sachets. One of the two feed points requires that product be delivered at a metered feed rate. The other feed point has its own auger, which regulates the flow from a mass transfer system. Only one of the two feed points can be in operation at any given time. Both feed points require that product be fed at a consistent flow rate to the packing head and be deaerated within specified tolerances.

To keep up with growth and demand for its products, the company wanted to take advantage of the economies of scale by having key ingredients delivered in 2200-lb bulk bags rather than in 55-lb packs. The challenge was to convey the product appropriately to the packer in the condition specified. To meet that challenge, the company contacted Power Process Systems to help find the best way to discharge the variety of products from bulk bags and deliver them via conveyor at the packing machine’s appropriate feed point.

Power Process Systems, which represents Spiroflow Systems in Ireland, consulted with Spiroflow’s technical support team at their headquarters in Clitheroe, UK. Spiroflow Systems Inc., a subsidiary operation located in Charlotte, NC, that services both North and South America, was also consulted. Together, Power Process Systems and Spiroflow Systems recommended that Gem Pack Foods install a bulk bag discharger that can connect to a Spiroflow flexible-screw conveyor or a vacuum conveyor. The flexible-screw conveyor delivers product at a metered feed rate while the vacuum conveyor delivers product en masse.

A Spiroflow Type 6 bulk bag discharger with a hoist design was recommended, since the discharger is located on the mezzanine floor of Gem Pack Foods’ main packing hall, which is too small to accommodate a lift truck. The innovative hoist design allows delivery and unloading of the bulk bags on pallets without the need for a lift truck. Each of the Spiroflow conveying systems selected is mounted on a mobile frame, enabling quick and easy changeovers between the systems.

A Spiroflow Type 6 bulk bag discharger dispensing
a one-ton bulk bag of key food ingredients at GEM Pack Foods

“Discharging the products with Spiroflow’s Type 6 bulk bag discharger was a walk in the park, since the unit came with integral base massage paddles and bag-tensioning support arms,” noted Pat Leamy, managing director of Powder Process Systems. “The challenge for us was to deliver the sugars and bulk ingredients to the packing machine in the condition specified so they could be packaged in the appropriate box bags or single-portion sachets.”

After consulting with the packing machine manufacturer, Leamy agreed that two methods of transferring product to the appropriate feed point on the packaging machine were required. “Gem Pack Foods accepted our joint proposal, and the system worked flawlessly to their complete satisfaction,” Leamy said.

One operator controls a standard one-ton hoist, which positions the full bulk bags into the discharger. This is done only after the flexible-screw conveyor and vacuum conveyor are in position below the discharger and its umbilical cord is connected to the electrical control panel. The hoist runs along a fully load-tested integral “I” lifting beam. The loops of each bag are attached to a lifting frame to ensure that each bag is lifted squarely into place. Once in place, bags sit on a substantial support dish while being stretched vertically by the compression springs within the side arms to assure total discharge. The side arms support the lifting frame used to raise the bag.

The support dish houses the base massager paddles, which can operate manually in case the product resists being discharged from a compacted or otherwise difficult bag. The aperture in the support dish, through which the outlet spout of the bag passes, is surrounded by an elastic membrane, which seals the base of the bag—even when the massagers are in operation. Below the support dish, a containment cabinet houses a spigot, which leads directly to the inlet of the conveyor positioned below. The neck of the bulk bag can be sealed to this spigot before the liner of the bag is untied, ensuring the dust-free transfer of the product onto the convey-or and eliminating product contamination from dust outside the bag or from atmospheric humidity.

The hopper that feeds the flexible screw conveyor contains an agitator that ensures a consistent flow of product into the screw and then into the packing machine. At 10 feet long, the conveyor raises the product 3 feet into a check sieve that is located directly above one of the packing machine inlets. The only moving part of the flexible-screw conveyor is a motor-driven spiral, which rotates within a sealed tube to gently move the material without degradation or risk of mixed-product separation. As a result, the system was economical to install, and it operates efficiently.

Flexible-screw conveyors can accommodate flow rates up to 10,000 cu ft/hr and a variety of tube diameters and lengths to exactly match plant requirements. The vacuum system collection hopper does not require an agitator. Conveying distance is 20 ft. Product is raised to a height of 10 ft into the collection cyclone and then placed into the packer by way of a rotary valve.

Spiroflow Systems Inc. is a manufacturer of dry-bulk-material–handling equipment. The company specializes in bulk bag discharge and filling systems and in flexible-screw, pneumatic, and aeromechanical conveyors. For more information about the GEM Pack Foods applications or other Spiroflow products or systems, call 704-291-9595 or visit www.spiroflowsystems.com.