Specialist packaging machine manufacturer BWI Dawson has designed and installed a new depalletising machine for New Zealand Milk using 'Lube-free Water Protected' drive chain from Tsubaki UK. The Lambda WP chain has enabled BWI Dawson to design a completely corrosion resistant machine for the first time, one that has to survive a daily washdown using hot brine in a food safe environment. New Zealand Milk, manufacturers of the Anchor butter brand import over 26,000 tonnes of butter into the UK every year.
The butter is wrapped in 25kilo blocks, stacked five layers deep and frozen for transportation.
The butter arrives on pallets holding 50 blocks each, it is then thawed, salted and processed for retail packaging on-site at their Swindon depot.
The throughput at Swindon amounts to 120 tonnes per eight hour shift and previously involved six lines of labour intensive unpacking.
This process is now carried out by four compact depalletising machines from BWI Dawson.
The machines receive 1250kilo pallets from forklifts in a lift well and raise them using stainless steel lift bars attached to two continuous loops of 1' pitch Tsubaki Lambda WP chain, the chain then indexes up as each layer of butter blocks is swept off the top pallet.
At any one time the chains can be lifting up to three tonnes of butter.
The mechanism that sweeps each layer of ten 25kilo butter blocks from the top pallet onto a conveyor is also driven by more Lambda WP chain.
Because of the food grade nature of the plant, each machine is washed down using high pressure salt water at 70oC after each shift.
The Lambda WP chain requires no external lubrication due to specially sintered oil impregnated rollers and is coated with a water protective finish.
It is able to work cleanly in a food processing environment and withstand extremely arduous conditions without corroding.
With a high load and exposure to fat and salt, plus high pressure hot washdown the Tsubaki chain is still operating perfectly after 12months.
Andy Temple, Project Manager at BWI Dawson commented, 'The Tsubaki chain was essential to the success of this project.
Our previous supplier could only offer us standard chain with external food grade lubrication, which would have been impossible bearing in mind the wash down conditions.
The combination of lubrication free operation and an extreme resistance to corrosion featured in this chain has allowed the project to go ahead, without it we would have been looking at a complete re-design.
The Lambda chain is also very strong and so we have been able to use a sensible 1' pitch for a high load, this has helped keep the machine compact and control the costs of peripheral equipment such as motors and sprockets'.
The new machinery has increased efficiency and aided the maintenance of strict hygiene levels at New Zealand Milk, the need for manual lifting and transfer with it's inherent risk has also been removed.
Empty pallets are also neatly stacked by the machine ready for removal adding to the new system's convenience.
Lube-free Lambda WP chain from Tsubaki is a unique product in the market place and is available through local distribution outlets and direct from the company at their Nottingham Head Quarters.
The Lambda series of chains is the only lube-free drive chain on the market that is available in attachment, conveyor and corrosion resistant variants.