Mannings Reduce Turbine Overhaul Time

Mannings Thermal & Environmental Engineers of Southport, England have introduced a method which uses patented technology for the rapid removal of large turbine bolts which has significantly reduced maintenance down-time for power generation specialists.

The new process was developed by Mannings USA and uses low voltage electromagnetic induction heating to apply heat where it is needed, to cause bolt expansion. As a result, all of the bolts on a typical HP turbine can be loosened and tightened within a ten hour shift which reduces expensive down time.

The new induction heating system uses a water-cooled wand, which is inserted inside the bolt itself. A variable frequency power supply is then applied to produce heat, which, causes expansion between the threaded areas and allows the securing nuts to be removed by hand or by normal hand tools. Heat transfer to the threads as well as to the turbine casing is minimal. In this way intense heat is directed into a small space in a short amount of time.

An important additional feature of the water-cooled wand is that, once the operation is complete the wand is cooled and can be removed safely. Steve Smith, who is in charge of induction heating at Mannings said, because the power requirement is substantially less for the overall process than the traditional high output cartridge heater, unnecessary heat transfer to other parts of the machinery is minimal”.

Mannings specialise in induction heating techniques and the USA research and development team have been able to improve efficiency, reduce costs and increase profitability for customers. They manufacture a wide range of induction heating and resistance heating equipment and accessories and Mannings provide the equipment and personnel to carry out work on site from their UK headquarters.