Abstract: For reducing the specific energy outlay in the grinding-drying of damp initial material, a circulating grinding system including a comminution machine, particularly an impact hammer, which is followed, via a sifter, by a high-pressure roll press operated in accord with the principle of product bed comminution, whereby the product admission of an impact hammer mill is connected to the feed for fresh initial material and the product discharge of a roll press is in communication with a product admission and/or with a product discharge of an impact hammer mill.

Abstract: A dryer system, such as is used in a pulverizing mill assembly, includes a hot gas generator which supplies drying gas to the starting point for a gas circulation system. The drying gas passes through the circulation system commingling with particles to be dried. The dried particles are removed whereupon the system gas flow is divided into a return portion and a spent portion for expulsion to ambient. Part of the system return flow is further freed of particles, compressed, and supplied to the hot gas generator as secondary gas. The return gas flow into the generator is regulated to control hot gas temperature in response to generator flow temperature. In addition, hot gas temperature may be controlled in response to system gas temperature by regulation of fresh primary air flow to the generator. Exhaust gases from the hot gas generator are introduced into the system return flow at the circulation starting point to repeat the process.

Abstract: A method is provided for adjusting or setting a definite position of rest of a rotary tube, particularly of a tube mill, by switching off the drive of the tube and is particularly characterized in that, at a time T.sub.o, the angular position of the rotary tube, or of a drive part rotating with a tube, referred to a plane of comparison is established, that the idling movement of the tube is predetermined between disconnection and final standstill, and the angular position of the rotary tube and/or of the time T.sub.x at which the drive is disconnected is calculated and effected.

Abstract: Method and apparatus for operating a process in which combustible solid particles are mixed during processing with air and circulated through a plurality of stages, thereby tending to build up an oxygen enriched combustible mixture during shutdown, the invention involving adding additional fuel to the oxygen enriched combustible mixture during such shutdown in a closed burner system, burning the resulting mixture in the closed burner system, and recirculating the flue gas from such combustion back into the plurality of stages to thereby function as an inert gas to prevent accidental combustion or explosion.

Abstract: A method and apparatus for the preparation of coaldust for use with a preheater and a cement calcination apparatus. Exhaust gas from the preheater is mixed with a source of coal and input to a pulverizing mill. The output of the pulverizing mill passes through an air current separator and a cyclone separator. The output of the air-current-separator, a stream of coal gravel, is supplied as a fuel at a calcination point in the calcination apparatus. The exhaust output from the separator provides an input to the cyclone separator which separates coaldust from the gas. The exhaust from the cyclone separator is in part fed-back to a calcination point in the calcination apparatus and is also a part of the stream of gravel. The entire process is closed so that no burnable coaldust is lost to the atmosphere.