The new 4+4 module concept for the LOESCHE mill
United Cement Company of Nigeria, a consortium consisting of the companies Lafarge and Holcim has ordered the largest LOESCHE mill to date, an LM 70.4+4. The company trusts in LOESCHE GmbH’s proven module concept, which was established at the beginning of the 1990s with the 2+2 mill.
Cement producers’ requirements for mill output continue to increase, with the result that LOESCHE GmbH has adapted its well-proven module concept to this greater mill output. Now, alongside the mill types with 2+2 and 3+3 rollers, the customer can also use a mill with 4+4 rollers. LOESCHE has already been building on this patented technology for over two decades. In the early 90s the 2+2 concept was patented, and later extended to the 3+3 module design. Now, a few years later, the development of the 4+4 grinding concept follows, which offers the customer outstanding flexibility. On the one hand, this allows the desired high throughput capacity to be achieved, and on the other hand, it offers the possibility of running just as well in 2+2 roller operation, thereby generating a mill output of 60%.
The success of having sold over 300 mills for grinding clinker and slag on the market allows LOESCHE to use this experience to further develop the trusted concept and to continue to provide customers with the well-known technology.
The innovative development in the LOESCHE mill type LM 4+4 is not only the expanded module concept but also the drive. The increasing performance requirements of cement producers led to rethink the further developments in drive technology. Particularly for larger mill outputs, LOESCHE favours a drive system with multiple motors and gearboxes with milling force decoupling.
In order to meet these demands, LOESCHE will use the COPE gearbox developed in cooperation with Renk, which offers a redundancy of up to 8 motors at the motor end. With all 8 motors in operation, a capacity totalling 8.8 MW is achieved. The new COPE gearbox contributes the feature of working without variable speed drive and also operating with a reduced number of motors. This means the new drive concept allows for operation with, for example, 7, 6 or only 4 of the available motors. Even in operation with only 7 motors, 100% mill output can be attained.
The COPE Gearbox from Renk for LOESCHE mill
Because this drive train works with the normal dimensions, the system is also suitable for retrofit gearboxes in existing mills. With this drive concept, LOESCHE can put a highly redundant, innovative drive system for the new LOESCHE mill type LM 70.4+4 on the market with short delivery times and low investment and construction costs. The new LOESCHE mill type LM 70.4+4 will be used with an output of 370 t/h 4 700 Blaine in UNICEM Nigeria’s new line in Calabar, Nigeria.
The delivery period is 14 months.
Loesche is an owner-managed, export-oriented company, which was founded in Berlin in 1906. Today, the company operates from its head office in Düsseldorf and has subsidiaries, representatives and agencies around the world, including South Africa.
In 1928 that Loesche built the first spring-loaded air-flow mills, which even today are still known as Loesche mills. Nowadays, Loesche vertical mills form the core of many plants used to dry-grind coal, cement raw materials, granulated slag, industrial minerals and ores.
Thanks to its grinding plants with throughputs of 2 to 300 t/h for the cement industry and self-inert, central coal-grinding plants for hard and brown coal power stations, Loesche is the global market leader for vertical mills and turnkey grinding mills.
Loesche supplies turnkey plants, which are individually planned and built for the required process steps. This includes plants for processing, material storage, transportation and delivery, vertical mills, hot-gas generators, filter and separator systems, complete automation technology, plants for all aspects of construction above and below ground, steel construction and piping systems.
The company has EN ISO 9001 certification and the grinding plants themselves are compliant with national and international safety regulations.
At present, around 330 people are employed at the company’s head office in Düsseldorf, with around 600 employed worldwide.