Device characteristics Solid fuel burner with the feeding screw of the latest generation is the solution that allows to use the wide range of fuels in the loose form, as well as the granulate of 0-32 mm. The essential fuel is coal with the granulation of 0-32 mm (from fine coals to peas). The design of the new nozzle of the burner and the application of the new method of fuel supply allows to use the so-called difficult fuels, e.g. coal with a high number of corners (cooking ability), which like to create sinters in the fireplace. For the construction of the feeder there is used cast iron, while the screw is made of spheroidal iron. This increases the resistance to corrosion, which provides prolonged life. This is very important when using fine coal, which does not occur in the dry state (let us remember that coal contains sulfur, which increases corrosion in combination with moisture). The application of cast iron reduces the feeder operation noise and has less tendency to transmit vibrations to other elements of the boiler. Cast iron is insensitive to deformations caused by temperature, which is important in the case of the screw, which becomes very hot when reducing the fuel level in the furnace (steel screws tent to have deformations caused by temperature).