The power of innovative engineering: The biggest LOESCHE mill type LM 70.4+4 CS in successful operation with the new COPE drive
Mfamosing – The cement plant at Mfamosing, located thirty kilometers north-east of Calabar, capital of Cross River State, Nigeria, is fully operational since February 2009 and equipped with the latest technology. With a capacity of 2.5 million tons cement per year the UNICEM plant has now been extended by LOESCHE technology.
The customer ordered two vertical roller mills. One of the type LM 60.4 for the grinding of cement raw material with a product rate of 500 t/h.
Cement clinker will be ground with the brand-new highlight, the LOESCHE mill type LM 70.4+4 CS.
This mill is designed for a capacity of more than 370 t/h. In combination with this enormous capacity a new drive system for an operation power up to 8,800 kW is necessary. In a close cooperation between RENK AG Augsburg and LOESCHE GmbH Düsseldorf this development was established. Input from the end-user LafargeHolcim, as well as from a renowned technical university in Germany, was taken into consideration.
The innovative result is the COPE (Compact Planetary Electrical) drive. The new concept is designed for gearboxes from 4,000 kW to 12,000 kW making a single and special motor (and risks) obsolete as well as eliminating the failure in the fast running first stage gear of conventional gearboxes. Some more advantages:
- having the same footprint as a standard mill gearbox for VRMs
- first time use of 8 drive motors for a VRM gearbox
- first time multiple drive in VRM to operate with or without VFD (Variable Frequency Drive)
- easy removal of individual mill motor units to minimize down times (approx.2 h)
- extremely compact design with motors directly attached to gearbox housing
The utmost important difference of this development is the fact that long stand-stills of a mill (for several months) due to the repair of any of the conventional gearboxes will be a matter of the past. Implementing the COPE drive requires the standard foundation. The replacement of one of the 8 small size motors will be easily conducted as they are readily available and easy to install.