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.
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.
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.
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 |
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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 | 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 |
Activate the markers for further information
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 |
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!