South Australian brewery installs gypsum blending system

Fresco Systems Australasia recently installed a gypsum blending system for a South Australian brewery in Adelaide. Specifically designed to replace an ageing manual process, the new system needed to reduce manual handling and achieve the highest levels of weight accuracies, dust control and mixer homogeneity. Fresco designed, manufactured and commissioned the system to ensure it met requirements. Adding to the complexity of retrofitting a system into an existing building was the old system, which was still operating and being feed from 20 kg bags, leaving limited space available.

The Fresco system metered gypsum into a mixing tank where it was blended into a solution of water. The powder was discharged from the flexible conveyor directly into the mixer vortex immediately being drawn into the solution. The loss-n-weight gypsum system used a batched weight which was controlled by the loadcells mounted under the bulk bag unloader. Addition rates of 50-60 kg per batch were metered into the water solution.

Gypsum quantities were controlled via recipe batch weights from the PLC and were uploaded to the weigh batch controller prior to each batch. The system would tare itself before metering the required batch weight. If there was insufficient product in the bulk bag the system would pause, request the operator to change the bulk bag and then continue completing the batch. The flexible conveyor elevated the gypsum from ground level up into the liquid mixer via a slide valve which provides an isolation barrier preventing the ingress of moisture into the flexible conveyor when not in use.

When moving to bulk bags, access for forklifts was important; however, the existing building layout prevented forklifts from gaining access into the area. The system was therefore designed to allow the forklift to load bulk bags from the exterior of the building through an electric roller door.

The modular design came pre-assembled, which allowed for quick installation and adaptability to the application. Due to the height constraint the split frame designed for low head room applications was used, which reduced the required head room by 1-1.2 m. This enabled the system to fit within the confines of the existing building and access door.

The Fresco forklift bulk bag unloader has four fully adjustable sturdy uprights, which allows for any size of bulk bag by simply removing the retainer pins and adjusting the vertical height of the support frame pockets. Bulk bags up to 2000 mm high and weighing up to 2000 kg can be accommodated in the standard Fresco bulk bag unloader.

Bag straps are quickly and easily secured to the forklift lifting frame providing a safe and secure attachment while being lifted and positioned in the pockets.

The bulk bag is attached to the forklift lifting frame before being loaded into the mid-section, which is also fitted with the bag massagers. The forklift then repositions to lift the mid-section complete with bulk bag onto the stationary base. The large location pockets allow for quick and safe positioning of each sub frame by the operator.

Once the bulk bag is safely positioned on the bulk bag unloader frame the spout of the bulk bag is pulled through the bag closer and into the interface chute. The operator closes the bag closer cinching the spout of the bulk bag before untying the spout of the bulk bag. The access door is then closed and the bag closer opened allowing the gypsum to flow into the hopper below.

Bag massagers encourage the gypsum to discharge from the bulk bag, which may have compacted during transportation. The massagers operate on a cycle timer when the flexible conveyor is running. Flow promotion in the hopper below is also required and vibration and agitation have been used to achieve this, preventing bridging and cavitating in the hopper.

A dust collector fitted to the hopper creates a negative vacuum in the interface chute preventing dust escaping to the environment and exposing the operator. The dust collector is fitted with a reverse pulse filter cleaning system which dislodges dust and returns it to the process.