Gearbox solutions at the heart of power plants
Published: 27 June 2016 - Sarah Mead
Industrial gearboxes are at the heart of power plants performing vital functions such as driving the huge air preheaters, coal crushers and pulverisers, cooling tower fans, turbine drives and conveying systems etc. The efficient and reliable operation of these gear units is essential to the smooth running of the plant as a whole. Power plant operators and OEMs alike benefit from partnership with a solutions provider able to offer a full range of services from design and manufacture of new units to maintenance and support on a global basis.
Renold Gears has the application knowledge and expertise to provide a comprehensive range of products and services to the power generation industry. This includes bespoke solutions for OEMs, the service and repair of installed units, even when obsolete, and the manufacture of replacement units that will fit perfectly into the footprint of the old one without any additional engineering work being required.
For example, the company 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. It also provides global service and repair, along with ongoing support, even for units manufactured by other companies. This all-round service is an important factor in ensuring all the drive units at a power plant function efficiently, reliably and downtime is minimised.
The range of APH drives includes multiple input helical worm and bevel-helical gear drive options with configurations to suit centrally or peripherally driven air preheaters. A multiple input helical-worm-worm option can be supplied with a hollow bore output for direct mount to the drive shaft, or it can be supplied with an optional rubber-in-compression coupling from Renold Hi-Tec Couplings. The gearbox can be direct mounted to multiple prime movers including AC, DC or air motors.
The bevel helical solution is a multi-stage design with the option of a solid output shaft, either vertically up or down, and with provision for multiple inputs and integrated sprag clutch holdbacks to prevent drive reversal. The drives also include a self-contained lubrication system. They can be either gear pump or electric motor driven and can be supplied with separately mounted gear motors for barring. The main motor is driven by a fluid coupling for soft starts. Both options can be manufactured in a range of sizes to suit power plants from 200 to 1200mw. Different torque requirements are dependent on the size of the power station.
Units can be manufactured for centrally driven air preheaters, including worm and helical gearing configurations that can be designed as drop-in replacements for originally supplied units, or designed to the OEM's specification for new applications. A central design has a solid output shaft and mounts directly on to the main rotor shaft of the APH and is secured by means of a shrink disc.
Alternatively solutions can be supplied for peripherally driven air preheaters. A peripheral drive is mounted on to the extremity of the APH and is supplied with a solid output shaft on to which a spur gear is mounted that drives the APH via an externally mounted girth-ring gear.