Ingenuity empties bags without dust or fuss

Tom Shelley reports on an ingenious piece of machinery that teaches a number of lessons about the improved handling of powders Clever mechanics enable the easy, fully controlled and dust free discharge of large bags of powder. Operator health and safety is ensured during untying, discharging, re-tying, collapse and removal of bulk bags exemplifying how one machine can be devised to deal with all aspects of a handling problem, provided it is carefully studied and thought through. In the BFC Bulk Bag Discharger, made by Flexicon (Europe) in Herne Bay, Kent, a bag is first raised into position, upside down, with the help of an electric hoist. A telescoping tube then raises a clamp ring assembly into position where it can seal the clean side of the bag spout to the clean side of the tube. The clamp ring is subsequently lowered until the bag spout is pulled taught. A 'Power Cincher' may then be applied to the bag spout. This consists of an arrangement of pneumatically actuated, curved, articulated, stainless steel rods, which cinch the spout concentrically in the horizontal plane. The rods engage each other in a zig zag pattern in the vertical plane to prevent leakage of fine powders. Application of the cincher ensures that when the spout is untied, the bag does not have to immediately empty fully in a sudden rush and flow can be shut off during emptying and the bag re-tied if required. As the bag is emptied, downward pressure from the clamp elongates the bag as it empties. The sides of the bag may also be massaged with side plates, called "Flow-Flexer bag activators", to loosen compacted materials and promote material flow into the discharge spout. As the bag lightens, the stroke of the side plates increases, raising the bag into a "V" shape, eliminating dead spots to ensure complete emptying. After emptying, an integral "Bag-Vac" dust collector system creates a negative pressure within the system to collapse empty bags prior to re-tying and disconnection, eliminating the cloud of dust traditionally emitted when workers manually flatten empty bags. The machines are available in carbon steel with a suitable industrial finish, or in stainless steel in industrial or food quality finishes. The concentric rod cincher works much better than opposing bars working as a pinch valve. It also does away with any need for iris valves working within the powder flow. The general principles of the machines are applicable to all kinds of powder handling. Flexicon (Europe) email Flexicon Pointers * The concentric rod cincher works much better than opposing bars working as a pinch valve and avoids the need for an iris valve * The application of vacuum suction at the end of bag emptying avoids the traditional cloud of dust produced when bags are flattened manually.