Moving grate Biomass boilers

Rapla Metall produces moving grates combustion chambers and hot water boilers with output range from 0,3MW to 5 MW. Moving grates furnaces are provided for hot water, steam or thermal oil boilers operating in heating systems.


  • High efficiency and low emissions
  • Strong and reliable solution
  • Water cooling of grates
  • Fuel level control with IR sensors
  • Cast and stacked masonry
  • Automatic cleaning of heating surfaces
  • Low maintenance costs
  • Reliable rated power considering the different fuels used and their moisture content
  • Long life
  • Quick and easy installation thanks to a standardized solution

Typical scope

  • Horizontal hot water boiler 6 bar 130 º conforms to PED 2014/68/EU
  • Moving grates furnace equipped with fuel feeder
  • Grates with a minimum chromium content of 26%
  • Cast iron side plates with a minimum chromium content of 26%
  • Primary air divided by combustion zones
  • Primary air fan with frequency controller 
  • Secondary air /flue gas recirculation fan with frequency controller 
  • Recirculation mixed with secondary air
  • Primary and secondary air ducts and regulating flaps with actuators
  • IR level sensors to maintain the fuel level of the grates
  • Level sensors and camera cooling
  • Preheating of the primary air by cooling the outer combustion chamber insulation lines
  • Refractory insulation, masonry and bricks
  • Hydraulic ash scraper under the grate for automatic ash removal
  • Hydraulic power unit for furnace grates, ash scraper. Shutoff valves, hydraulic pipelines
  • Hydraulic cylinders for furnace grates, ash scraper
  • Automatic smoke tube cleaning system, pneumatic 8 bar
  • Optional: water-cooled standing and moving grate bar carriers


  • wood chip
  • bark
  • chunk peat
  • milled peat and wood chip mixture
  • wood pellets, peat pellets.
  • Fuel moisture 10-60%
  • Size [nominal length mm]: ≤ 50 
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