DE  |  EN  |  FR  |  ES

MVR vertical roller mill with planetary gearbox

MVR vertical mill with conventional drive: economical solution for small to medium output rates

For the preparation of cement raw material, cement, and granulated blast-furnace slag with small to medium output rates, the MVR mill with conventional drive is the right choice. This mill type is by the way the core piece of our modular ready2grind system. High plant availability and optimized maintenance concepts are the features that make sure the mill meets the ever rising requirements of the industry. In combination with the conventional drive, the MVR mill ensures small to medium output rates, reliably and on the long term.

Advantages of the MVR mill with conventional drive

Grinding roller system with active redundancy

Up to six grinding rollers may be swung out separately, using only one hydraulic unit for maintenance and operation. This system is actively redundant meaning that operation continues while two or several opposite grinding rollers are taken out of the system.

Homogeneous compaction of the material to be ground

Thanks to the geometry of the grinding rollers in combination with their specific suspension, there is always a parallel grinding gap, ensuring a homogeneous compaction of the material to be ground. Moreover, due to the symmetric shape of the grinding roller tires, these can be turned when worn.

Low capital expenditure

MVR mills need only few peripheral machinery, no or little walled-in space, their operation is dust-free and they have a low noise level.

Low electric energy consumption

The grinding principle and the high efficiency classifier ensure the reduction of electric energy consumption by up to 40% as compared with conventional ball mills.

Optimum utilization of process heat

The thermal energy of process gases can be used on MVR mills.

Highest availability

Thanks to low specific wear rates, high-quality wear materials and sophisticated service concepts, maintenance times of the MVR mill are reduced to minimum which is additionally supported by the active redundancy of the grinding rollers.

Favorable control behavior

High drying capacity, short dwell time of the material to be ground, and remote control of grinding pressure and classifier rotor speed ensure a fully automatic operation of the MVR mill even with varying raw material characteristics.

Increase of output rates by installing a MultiDrive®

The Pfeiffer MVR mill may also be equipped with the patented MultiDrive®. Learn more about this innovative drive system.

Design principle and technical data

Select application envisaged

F
M
H
1
2
3
4
5
6
7
F Fines
M Material to be ground
H Hot gases
1 SLS high efficiency classifier for sharp separation
2 Optimized free flow areas
3 Rollers can be swung out separately with hydraulic system
4 Rollers can be lifted off
5 Parallel grinding gap
6 Space-saving twin support for largest possible maintenance access
7 Maintenance drive

Working principle

Up to six stationary grinding rollers roll on a rotating grinding table. The material is drawn in between the rollers and grinding table and ground by pressure and shear. The required pressure forces are produced by a lever system comprising, among others, a roller arm, along with a hydropneumatic tension system. After being rolled over by the rollers, the material is conveyed to a stationary nozzle ring due to the rotation of the grinding table. Gases (air or hot gas) flow through this nozzle ring, take up the ground and dried material and convey it to the classifier where it is separated by the rotating wheel (rotor) into grits and fines. The grits fall back into the grinding zone whereas the fines leave the classifier with the gas flow for being separated in cyclones or a filter.

Technical data
Throughput rate up to 650 t/h
Mill drive up to 6,500 kW
Number of grinding rollers up to 6
Feed size up to 120 mm
Feed moisture up to 20%
Target fineness degrees 60 – 100 µm
Classifier high efficiency classifier
Grinding table diameter up to 6,000 mm
Gas volume flow 1,500,000 m³/h
Feed material cement raw material
F
M
H
1
2
3
4
5
6
7
F Fines
M Material to be ground
H Hot gases
1 SLS high efficiency classifier for sharp separation
2 Optimized free flow areas
3 Rollers can be swung out separately with hydraulic system
4 Rollers can be lifted off
5 Parallel grinding gap
6 Space-saving twin support for largest possible maintenance access
7 Maintenance drive

Working principle

Up to six stationary grinding rollers roll on a rotating grinding table. The material is drawn in between the rollers and grinding table and ground by pressure and shear. The required pressure forces are produced by a lever system comprising, among others, a roller arm, along with a hydropneumatic tension system. After being rolled over by the rollers, the material is conveyed to a stationary nozzle ring due to the rotation of the grinding table. Gases (air or hot gas) flow through this nozzle ring, take up the ground and dried material and convey it to the classifier where it is separated by the rotating wheel (rotor) into grits and fines. The grits fall back into the grinding zone whereas the fines leave the classifier with the gas flow for being separated in cyclones or a filter.

Technical data
Throughput rate up to 320 t/h
Mill drive up to 6,000 kW
Number of grinding rollers up to 6
Feed size up to 120 mm
Target fineness degrees 1,500 – 6,000 cm2/g
Classifier high efficiency classifier
Grinding table diameter up to 6,000 mm
Feed material cement, granulated blast-furnace slag

Maintenance

Wear protection/maintenance

Depending on the abrasiveness of the material to be ground and areas to be protected, different wear materials are used on our vertical roller mills. Alloy cast iron as per DIN 1695, hardfaced cast iron or composite materials with high-chromium inserts in ductile base materials: the grinding elements designed by Pfeiffer are made of high-quality materials ensuring a long lifetime. The housings and other mill components, too, are protected against wear with highly wear-resistant steel plates or hardfaced composite plates. Components which are specifically exposed to wear like gas outlet ducts have additional ceramic liners. All this is for optimum protection and short maintenance shutdown.

Swing-out system of rollers on MVR mills

The highest wear occurs on the wear parts of the grinding elements as is the case with any type of vertical mill. Therefore, ease of replacement and regeneration is a major feature of the mill. The MVR mill has a modern hydraulic system used in operation and for maintenance alike. With this new type of roller suspension, the rollers can be swung out of the mill in a controlled way – for ease of replacing the one-part grinding roller tires. The segmented wear parts of the grinding table are replaced, using a lifting device and the maintenance drive. Moreover, the rollers can be swung out separately. Hence grinding operation can be continued while taking out two opposite rollers at a time. The parts concerned can be regenerated both inside the mill and outside. Forget about downtime and maintenance problems! With active redundancy and easy maintenance you are up to date!

Bearing replacement

Roller removal

Segment replacement

Our vertical mills with planetary gearbox