Pulverizing installation

A pulverizing installation comprising a ball mill including a rotary drum (11, 12, 13) having a horizontal axis (XX′) and each end of which comprises a journal (14, 15) resting on a bearing (16, 17), the mill being fed with material to be pulverized and with gas via at least one of its ends by means of a feed device comprising a feed pipe (6) for feeding with material to be pulverized, a rigid gas injector tube (41) passing axially through the corresponding journal (14, 15), said rigid tube (41) and said journal (14, 15) defining therebetween an annular duct (35), said feed pipe (6) discharging into said annular duct (35) in the vicinity of the corresponding journal (14, 15), said journal (14, 15) containing a rigid helicoidal Archimedes screw structure (32) disposed about said rigid gas injector tube (41), said rigid helicoidal structure (32) turning with the drum when it drum rotates in order to feed the material to be pulverized towards the interior of the rotary drum (11, 12, 13), an outlet duct (36) communicating with said annular duct (35) for ejecting the mixture constituted by the gas and by the material pulverized in the form of powder, out of the drum, the installation being characterized in that said feed pipe (6) for feeding material to be pulverized is substantially vertical and discharges into said annular duct (35) at the level of a guide member (31) for directing the material to be pulverized as conveyed by the pipe (6) towards the drum, in that said rigid gas injector tube (41) is held immobile and penetrates into the journal (14, 15) by passing through said guide member (31) from the outside, and in that said rigid helicoidal structure (32) is fixed to the journal (14, 15).