Renold Gears designs and manufactures a complete range of specialist drive solutions for the huge air preheaters (APH) found at gas, oil and coal fired power stations. These air preheaters are very large fans that preheat the combustion air before it enters the boiler to improve its thermal efficiency. This is achieved by recycling the hot flue gas as it leaves the furnace, heating the elements of the fan as it is turned slowly by an APH gearbox. This heat is then transferred to the air as it enters the boiler.

Renold provides solutions for different types of air preheaters including new designs for OEMs or replacement drives to power stations. This includes multiple input helical worm and bevel-helical gear drive options with configurations to suit centrally or peripherally driven air preheaters.