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Multiple drive for vertical mill - MultiDrive®

Active redundancy of drive system as a protection against total failure

The MultiDrive®, which has proven successful in industrial operation since 2008, was developed by Gebr. Pfeiffer in cooperation with Siemens/Flender especially for the MVR mill. What makes this multiple drive unique all over the world is the fact that there may be up to 6 independent drive units which are actively redundant both electrically and mechanically. Another feature to be found only with this type of drive: delicate gearbox components are not located under the grinding table, thus ensuring an unparalleled technical availability of the drive system. In case a drive unit fails, which is rather improbable, the unit concerned can be taken out of the system, with the others still operating, so that your MVR mill will continue producing, sometimes even without a reduction of throughput. One more benefit among several: thanks to the perfectly adapted combination of Pfeiffer MVR mill and MultiDrive® , you will achieve production rates for which you would normally have to provide two vertical mills operating in parallel.

Advantages of the MultiDrive®

Individual drive design

Depending on how much power you need, you may choose the suitable MultiDrive® with 3 to 6 identical drive units reaching a power rating of as much as 18,000 kW.

Ease of maintenance

Radially arranged on movable supports, the drive units can be withdrawn easily from the mill. Moreover, with a maximum 25 t per drive unit, the MultiDrive® has a much lower weight than a conventional gearbox and is a lot easier to maintain.

Efficient stock-keeping

Owing to the modular and lightweight design, using only standard components, stock-keeping becomes easier and less expensive. There is an additional benefit: one drive unit can be used for several mills with MultiDrive®.

Optimum return on investment

There is no other mill drive concept ensuring such minimum downtimes and hence minimum production loss. Even if unplanned shutdowns occur, the Pfeiffer one-mill solution with the MVR mill, where production can be continued, is always better on the long run in terms of ROI as compared to a two-mill solution.

Reduced space and costs

The MultiDrive® has the lowest construction height of all mill drive concepts available on the market. Your benefit: the MVR grinding plant is more compact and cost-efficient than any other system.

Flexibility thanks to variable grinding speed

When grinding different materials with highly varying grindabilities and target fineness degrees, the system can be run with a frequency converter for speed variation. If you do not need such frequency converter right from the beginning, you may retrofit it anytime to adapt to changing requirements.

Design principle and technical data

Select application envisaged

1
2
3
4
5
6
1 up to six identical and independent units driving the girth gear
2 grinding forces are taken up directly by the foundation, no delicate gearbox components
3 gearbox comprising only standard components
4 motors with fixed or variable speed
5 compact grinding plant design, lowest construction height available on the market
6 lightweight drive units can be removed separately on movable supports

Working principle

3, 4 or 6 identical MultiDrive® units comprising motor, coupling, and gear driving the girth gear of the table thrust bearing, with a total power of 18,000 kW.

Technical data
Drive power up to 18,000 kW
Number of drive units up to 6
Either with or without speed control via frequency converter
1
2
3
4
5
6
1 up to six identical and independent units driving the girth gear
2 grinding forces are taken up directly by the foundation, no delicate gearbox components
3 gearbox comprising only standard components
4 motors with fixed or variable speed
5 compact grinding plant design, lowest construction height available on the market
6 lightweight drive units can be removed separately on movable supports

Working principle

3, 4 or 6 identical MultiDrive® units comprising motor, coupling, and gear driving the girth gear of the table thrust bearing, with a total power of 18,000 kW.

Technical data
Drive power up to 18,000 kW
Number of drive units up to 6
Either with or without speed control via frequency converter

MultiDrive® concept for elimination of weak spots

When designing the MultiDrive®, the engineers aimed at avoiding the weak spots of conventional single planetary gearboxes that cause long downtimes and work-intensive repair. Basically the vertical mill gearbox serves to transmit the motor couple to the grinding table. Moreover, it directs the grinding forces into the mill foundation. Unlike on conventional gearboxes, these two functions are completely separate on the MultiDrive® what makes it so unique and trend-setting. Therefore, delicate gearbox components are not to be found under the grinding table where they would be exposed to the highest grinding forces. Your benefit: considerably reduced wear and highest availability as the vertical forces occurring under the grinding table are directed completely into the foundation, passing through sliding bearings which have proven in industrial operation.

With active redundancy you can forget about downtime!

The intelligent design of the MultiDrive® perfectly fits the trend-setting Pfeiffer MVR mill because with both elements together, active redundancy is ensured for the mill drive and grinding rollers. Up to six independent drive units, each comprising an electric motor and gear, engage with a girth gear flanged to the neck of the grinding table transmitting their torques to the latter. For maintenance purposes or in the unlikely event that a failure should occur, one or several drive units can be disengaged, without causing a stop of production. This is your protection against total failure!