As with many manufacturers, efficient pallet transportation in the brewing industry is essential to maintain cost effective production. In one brewery, for example, 18 conveyors are being used to transport pallets from the production area to the warehouse. Each of these is 9.75m long and consists of three strands of FVT90 chain which runs at a speed of 15m/min, powered by a 7.5kW drive motor.
There are eight pallet positions on each conveyor, which are designed to convey a stack of three pallets, each holding eight barrels. This arrangement places a load of 1,620kg on each conveyor position, allowing each to transfer up to nearly 13 tonnes at any one time. This would therefore mean that a failure of just one conveyor would have a significant impact on production efficiency.
A frustrating issue
To improve the durability of the storage system, the pallets were changed from wood to plastic, allowing them to be reused a greater number of times. However, the new pallets became contaminated by the lubrication oil on the transport chain which, in turn, was transferred to the barrels – increasing the number of barrels that had to be rejected.
To overcome this, the brewery decided to stop the lubrication of the transport chains. This, however, has resulted in rapid elongation and the rollers within the chain wore quickly and unevenly due to the stick-slip effect. This then increased the load on the drive motor, causing the thermal trip to cut power to the motor, resulting in loss of production and maintenance costs. Frustrated by the issue, the brewery approached Tsubaki for a solution.
An initial inspection revealed the issues with the conveyor chain, so Tsubaki suggested that it be replaced with a maintenance-free alternative consisting of two strands of Tsubaki Bearing Roller Conveyor Chain Lube-free Series.
This chain uses special cylindrical bearings that provide self-lubricating properties between the bushes and the rollers, enabling the chain to perform without the need for additional lubrication. According to the company, tests have shown that this design provides five times the wear life of AT Series general use conveyor chain, providing a long lasting and reliable solution. The expected lifetime of the chain is now 15 years, compared to four years in the previous setup.
The design of the chain allows the cost of lubrication to be eliminated as well as reducing the load on the drive motor to such an extent that the original motor could be replaced with a 1.5kW version.
Of additional benefit, this means that the annual energy consumption for the conveyor system is reduced from 27,000kWh to just 5,400kWh. In turn, this has reduced the associated CO2 emissions to 20% of the original figures.
The completed installation has greatly improved the reliability of the production line and significantly reduced the amount of lost production. In addition, savings have also been made in maintenance costs by eliminating the need for lubrication as well as the reduction in energy costs.