Savings in downtime and material costs plus improved, faster production have been achieved by Colfix at its Dublin bitumen processing plant by replacing a manually-fed rigid screw conveyor with a Spiroflow bulk bag handling system. The new equipment comprises a Spiroflow Type 2 bulk bag discharger and a Type 5 low loading bulk bag discharger, each having a 2m Model 120 flexible screw conveyor which meters product to a 50 litre transition hopper. This acts as the in-feed hopper to a PC4 aero mechanical conveyor that then takes the product at a steep angle through a wall to a mixing vessel mounted outside the building. The previous rigid screw conveyor was manually fed using 25kg sacks and could not cope with the higher capacities of bulk bag handling.

The Spiroflow system handles bulk bags containing 750kg of product, giving a 30 times reduction in manual handling. Colfix uses rubber crumb to make polymer modified bitumen, aspecial form of binder widely used on roads to hold the surface together. Colfix either emulsifies the polymer modified bitumen or sends it to their customers to make emulsions, macadam’s, asphalt’s etc. The Spiroflow flexible screw conveyors have a variable feed rate to suit the plant’s mixer requirements. The control system incorporates a counter allowing three bulk bags to be discharged into the mixer, after which the cycle is manually restarted. Once the flexible screw conveyor has discharged the entire contents of the bag, the aero mechanical conveyor is allowed to continue running until all product has been elevated to the mixer. The dual system allows for changeover of a bulk bag on one system while the other one is discharging. The whole system is sealed against the escape of dust. Colfix can now enjoy the cost benefits of buying in bulk as well as the reduction in manual handling.