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Uncle Ben's of Australia's Wodonga plant manufactures a wide variety of pet food products on a continuous basis, operating 24 hours a day, 7 days a week, for periods of 12 days at a time. More than 2,400 product change-overs are performed annually.
Analysis of the results of the benchmarking program undertaken by the company identified reduction in waste at product change-over as one of the best initial opportunities to improve its environmental performance and its economic efficiency. At the commencement of our investigations, the quantity of waste generated by each product change-over was estimated to cost $200,000 annually.
Most of the line between the mixer (where all meats, gravy and liquid ingredients are blended) and the filler (where the product is canned) is 'pigged' during a product change-over. In this process an air-driven projectile is forced through the line, pushing all product to the filler, leaving minimal product in the line. However, at least five metres of line remains unpiggable because of restriction by in-line magnets and the product pump.
Until recently, the company would flush the in-line magnet with water at each product change, the flush water being pushed through the line (by the new product) and dumped at the filler.
A team of production operators, investigating how to optimise product change-over, proposed installing dump valves near the in-line magnet to allow the flush water to be dumped as the flush occurred. This would remove any potential for contamination of product.
At a cost of $40,000, this initiative is saving about $100,000 each year and is reducing the average time for product change-over by almost one minute. As the original idea came from production operators, the obstacles to implementation were minimal. Automation of the flush operation ensures no detrimental effect on excisting processes.
The next opportunity is to remove the product left in the 5-metre section of the line at product change-over before commencing the magnet flush. The means of achieving this goal was inspired by a sister plant where air is used to remove product with similar characteristics to pet food.
As a development activity, an air line was connected to the product lines at the base of the mixer, and a trial conducted with the pump running at slow speed while the air forces product towards the pig launching station. Initial trials suggest a yield of 75 per cent of the line contents.
The next stage of this project will be to provide actuation of the air purge valves and develop software to control their operation, along with that of the product pump. The cost of conducting trials was negligible compared with the potential savings. The magnitude of potential savings suggested by recent trials has ensured interest in completion of the project.
Upon completion of the project, a follow-up audit will benchmark the level and sources of waste generation at product change-over. The cost associated with each waste source will be evaluated, and teams set up to investigate cost-effective methods of eliminating or reducing these waste sources. It is important to bear in mind that even incremental improvements can bring significant savings.
This case study was prepared by the Department of Innovation, Industry and Regional Development, Victoria. Environment Australia would like to thank them for allowing us to display their case study on our web site.