Preheater drives improve boiler efficiency

Renold Gears is expanding with gear exports from the UK into China.

Rapid economic expansion in Chinese industry has created huge demands on electrical power; this has resulted in a massive rise in the construction of new fossil fuel power stations across the country.

These power station boiler applications require highly efficient and reliable air preheaters to ensure optimum boiler performance.

As the preheater slowly rotates, at around 1-2rev/min, the elements collect heat in the hot gas stream and then transfer it to the cold air stream.

Preheating the air leads to a more efficient boiler performance.

Renold Gears manufactures and supplies, from its factory in Rochdale, two drives for boiler preheaters.

Both units having multiple inputs.

The first is a shaft-mounted gear unit, based upon the TW series, which is fitted to the central main shaft of the preheater fan and fixed into position using huge shrink disc couplings.

Each drive is a multiple reduction unit comprising two sets of wormgears and a primary helical box with a further two helical reductions driven by an electric motor.

Since it is imperative that the fan of the preheater must continue to turn indefinitely, the gearbox is fitted with a further two flange-mounted drive motors to act as stand by drives in case of motor failure.

The second option uses a design based upon the HC series.

It is a two-stage helical unit with a bevel gear first reduction, mounted with three first reduction bevel gears, giving three separate input drive shafts.

These input shafts are separately coupled to primary drive, in-line helical, foot mounted, double reduction geared motor units from the RP range.

Roger Godson, Renold Gears' Sales Director, commented "It is testament to British engineering that whilst so many companies in Europe are being challenged by goods imported in from China, Renold Gears' experience in gear design and manufacture is expanding with exports from the UK into China".

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