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Rotary kilns

Latest drive systems for rotary kilns

The rotary kiln is the core of lime and cement clinker production. In the slightly inclined cylindrical tube, which rotates around its longitudinal axis during the firing process, the lime powder is heated up to 1450 °C and burned into cement clinker. The rotation has both a transport and an air injection effect. The length of such a kiln can be well over 100 meters. In this type of kiln, the limestone is added at the slightly higher end and slowly passes through the kiln due to the rotation. All drive elements must also be inclined accordingly. FLENDER offers the latest drive systems for rotary kilns.


  • FLENDER planetary gear units
  • FLENDER helical and bevel-helical gear units
  • FLENDER auxiliary gear units with integral overrunning clutch and centrifugal brake,
  • Holding brake
  • FLENDER couplings
  • Frequency controlled Siemens electric motors
  • Siemens auxiliary motor


Your benefits at a glance

 FLENDER planetary gear units

  • Greatest power capacity and very high reliability
  • High efficiency and best performance
  • Very high degree of modularity
  • Large number of sizes
  • Simple, time-saving project planning
  • Comprehensive add-on parts
  • Compact, space-saving design
  • Auxiliary drive mounted on the side of the main gear unit
  • Gear units, torque reaction arm system, motors, couplings, brakes, oil supply systems are supplied ready for installation (everything from a single source)

FLENDER helical and bevel-helical gear units

  • Highest level of reliability and fail-safe operation
  • Great Variety of versions in a torque range from 3,300 up to 1,400,000 Nm
  • Short delivery times
  • Rapid worldwide availability
  • Attractive price-performance ratio
  • Comprehensive add-on parts


  • Very robust gear unit with torsionally rigid housing in foot-mounted design
  • Solid, case hardened gear teeth
  • Robust bearings for gears and shafts
  • Oil supply of gears and rolling bearings by a combination of dip and forced lubrication
  • Separate oil supply systems with motor oil pump, oil cooler, double change-over filter and various monitoring instruments are used, all of which are mounted on a base frame.