Qube Bulk manages more than 20 million tonnes of bulk product shipments per year, which now includes filling of bulk bags with three abrasive mineral sands for Cristal Mining Australia using a Flexicon Bulk Bag Filling System.
When Cristal decommissioned its in-house bagging operation, Qube Bulk’s Picton facility devised a bulk bag filling solution in concert with Flexicon Corporation. The result is a mobile system that fills up to 80 bulk bags, or 160,000 kg, with the abrasive materials per eight hour shift—automatically, accurately and dust-free, claims Flexicon.
Bulk truck shipments from Cristal’s mineral separation plant are delivered to storage sheds at Qube Bulk’s Picton facility. Productivity is key to the bulk bagging process, according to Jos Pascoe, Qube Bulk regional manager. “Often, due to market situations, we receive orders fairly late and need to bag the product in a short time span to get the shipping containers loaded with bulk bags and to the port on schedule,” he says. “The need to respond to orders for any combination of the three materials stored in different sheds demanded a mobile solution.”
Flexicon proposed a skid-mounted mobile bulk bag-filling station having a 2.5 m3 capacity hopper and a 220 mm-diameter, 3m-long rigid tube screw conveyor moving materials to the bulk bag fill head. It delivers 20 m3 per hour, filling bulk bags weighing 1,000 kg or 2,000 kg. The skid measures 4 m by 2.25 m, and the unit stands 3.4 m high.
A forklift moves the mobile filler between storage sheds, depending on which material needs to be loaded. Pascoe reports that the system, including its 2.75 m-long offload roller conveyor, can be set up and running at a new location in 20 minutes or less.
Once an order is received and the filling station is positioned in the appropriate storage shed. Pascoe’s crew can fill up to 80 bags per eight-hour shift. He says about half that time is actual material filling and half is spent placing pallets, hanging empty bags and conveying filled bags out of the station.
A skid-steer loader empties bulk material into the feed hopper. The bottom of the hopper funnels the granular mineral into the steel tube screw conveyor inclined at 45º. The conveyor is equipped with a heavy-duty stainless steel spiral to handle the free-flowing but abrasive mineral sands, which range in density from 2200 kg/m3 to 2750 kg/m3. The design of the conveyor itself does not include any bearings or rotating seals, and the drive motor is mounted above the discharge point, preventing abrasive minerals from grinding on bearings or seals at the drive shaft. A pneumatically-operated product sampler automatically captures a 142 g specimen from the material stream during the fill cycle, for product quality documentation.
In keeping with Australia’s focus on workplace health and safety. To this end, the pivot-down fill head allows safe, rapid connection of the bag loops to the filler latches without standing on the roller conveyor straining to reach overhead bag connection points or inserting hands between fill head components.
Dust is contained by an inflatable bag spout seal and a telescoping discharge chute between the conveyor outlet and filler inlet, and by venting displaced air and dust to a filter sock.
Once a bag is filled, the latches automatically release the bag loops and the roller conveyor moves the bag out of the filling area for tagging and transfer to the shipping container.
The unit’s PLC automates everything except connecting of the bag straps to the latches and pulling the bag spout over the deflated spout seal. Load cells under the filler send signals to the PLC to stop the conveyor when the bag gains the desired target weight. The PLC also automates other aspects of the process including activating the powered roller conveyor and product sampler and other actions based on feedback from sensors.
