As engineering technology evolves, efficiency follows its footsteps

If you’re used to working with the same old technology doing the same old job, it’s almost inevitable you’ll opt for the same old solution when there’s a problem. ‘If it ain’t broke, don’t fix it’ subconsciously becomes: ‘If it is broke, fix it the way we always have.’

A fresh perspective is something ERIKS brought to a drives issue at a water treatment plant – enabling one planetary gearbox to do the work of a far more complex set-up of three gearboxes and drives.

Past its best

In the words of ERIKS Project Engineer Alex Price, the worm drive that arrived at ERIKS’ Pensnett workshop in the West Midlands had ‘seen better days.’

Designed to produce torque of just over 76,000Nm at 0.167rpm, the drive was one of three operating in line to power scrapers that rotate on the bottom of settlement tanks to separate the solids from the liquid effluent. Originally installed over half a century ago, it had been repaired countless times – including skimming the bearing faces and replacing the worm gear. But this time, to ERIKS’ experts, it looked as if it’s time had finally come.

Three into one

The application was using three reductions, including a chain drive, to achieve the required result. This had been the best technology available at the time, but half a century on ERIKS’ proposal of a planetary gearbox offered a simpler, more efficient, more cost-effective solution.

Firstly, it replaced all three drives with just one planetary gearbox. Less complexity means a smaller risk of breakdown and simpler, easier maintenance. Complete elimination of the chain drive, for example, meant complete elimination of the need for chain maintenance.

Secondly, the new gearbox is designed to occupy precisely the same footprint as the original system. So, there’s no reworking required before installation.

Thirdly, compared with manufacturing a new like-for-like replacement, ERIKS’ solution took two weeks to design and just eight weeks to manufacture, including two weeks of Christmas holidays which fell during the order period.

With new developments in engineering happening all the time, there’s often a new and better solution than ‘the same old, same old.’ That’s why it can be a valuable exercise to let an expert take a fresh look at a problem.

Engineers for ERIKS Projects for Rotating Equipment & Services can assess issues with larger projects, and propose solutions to increase reliability, improve efficiency, reduce maintenance, save energy and save money. As well as providing a full CAD redesign to demonstrate the potential.

For the customer at the water treatment plant, the cost of the planetary gearbox was £30k, whereas the cost of the repair would have been in the region of £70k. However, upon further investigation, the existing unit was deemed unviable for repair.

Not only did the customer save approximately £40k on the repair, they now have an off-the-shelf solution, meaning that spares are readily available, reducing leading times and costs further. Also, throw in the fact that a new gearbox is far more efficient than the old unit, and will last many years longer than a repair that has a finite life, then savings will just keep mounting.

The reliability and cost-savings so impressed the customer, they placed an order for an identical unit for another treatment plant as soon as the first was installed. With the design already perfected, it will only be a matter of weeks before the next unit is ready to go.

So, is the customer satisfied? Got it in one.