Abstract: A fine crushing device for mineral or vegetable particles comprising a closed chamber, the bottom of which, of frustoconical shape, is provided with an exhaust opening and inside which is arranged a sifting screen defining with the chamber cover a flat cylindrical volume inside which rotates at high speed at least one rotary knife, whereby the product to be crushed, introduced through a feed opening provided in the cover, is reduced in particles of required fineness through successive impacts against the knife or knives until they pass through the screen.

Abstract: Apparatus for feeding finely powdered material from a silo to a device illustratively a burner, in which the material in the silo is fluidized and extracted through a proportioning device, such as a screw or a distributor having alveoles. The material from the proportioning device, which is discharged intermittently, is supplied to a regulating tunnel where it is further fluidized and then discharged to the downstream side of a venturi whose upstream side is supplied with pressurized air. The fluidizing air in the silo and the regulating tunnel are preferably at the same pressure.

Abstract: The invention comprehends a burner for powdered fuel comprising an annular conduit for the injection of solid fuel in powder form, included between two coaxial conduits for the injection of air, one internal and the other external in which the three conduits discharge into an expansion and stabilization chamber which is formed by a divergent truncated portion connected to the external air injection conduit and which also has a central cylindrical portion and a terminal convergent truncated portion.