Glasgow-based Heliex Power is using cylindrical roller bearings from Schaeffler (www.schaeffler.co.uk) for its innovative range of screw expanders and generating sets, which capture energy from ‘wet steam’ and have been installed in industrial plants, incineration plants, farms and nurseries around the world.

Although harnessing energy from steam is not a new idea, the key innovation in Heliex Power’s patented technology is that it can operate with standard industrial ‘wet steam’, which often contains water droplets that would destroy traditional machines and generators.

It can generate power, re-energise low-pressure steam, and drive machinery and air compressors by using a building’s existing steam supply.

The Heliex System is a compact rotary device that operates at 4,500rev/min, driving a 3,000rev/min asynchronous generator via a toothed-belt transmission.

The bearings play a critical role, and they must withstand harsh operating conditions, including temperatures up to 200°C.

Engineering manager Nick Alexander says: “In our Heliex System, the function of the bearings is to ensure that the components inside do not clash, so we require very accurate location of the two rotors relative to each other.

“The tolerance between the rotors and the housing is also extremely tight; movement and back-pressure are critical, so the bearings are pre-loaded accordingly.

“They are also ‘heat-stabilised’ to ensure that they can withstand the large temperature ranges that our machines operate in.”

To date, Schaeffler has supplied hundreds of cylindrical roller bearings and angular-contact ball bearings for use on both test and development machines at Heliex Power — and on the current range of screw expander machines and generating sets.