Abstract: The invention relates to a roller mill with two rollers, a grinding gap formed thereby and a material inlet shaft the end walls of which bear on their lower ends carrier plates with replaceable sintered metal wear parts. Each wear part is formed by a plurality of small sintered metal plates of small area which are set close against one another like a mosaic and are individually screwed onto the carrier plate so that in case of wear only those small sintered metal plates which are actually worn can be replaced simply, quickly and economically.

Abstract: A rotary kiln has a sealable separating gap between the kiln outlet head and an inlet shaft leading to a cooler. In order that the shortest possible drop height for the fired material falling out of the discharge end of the rotating cylinder may be maintained despite the separating gap, interengaging steps and side openings defined thereby are formed in the side walls of the kiln outlet head and the inlet shaft, and sections of the separating gap which run at different heights open into the side openings and the horizontal distance between any two steps lying opposite one another corresponds approximately to the maximum displacement path of the kiln outlet head.

Abstract: A ring gear mounted for rotation and driven by a pinion which dips into an oil bath is provided on each face with a sealing device. Each sealing device has a conical annulus tapering in a direction away from the ring gear and on which a ring is positioned in spaced relation with the gear. There thus is formed between the gear and each ring an annular oil collecting chamber which leads oil carried upwards by the ring gear back into the oil bath.

Abstract: A device for sealing the gap between the inlet end of a rotary kiln and a stationary inlet housing. In this device a ring which is capable of sliding in the axial direction is supported on a stationary ring by at least one first annular sealing element, and the sliding ring has on its end facing the rotary kiln a first wearing surface which co-operates with a second wearing surface on a rotating ring fixed on the inlet end of the rotary kiln. Cylinders operated by a pressure medium urge the sliding ring in a direction towards the inlet end of the rotary kiln and hold the two wearing surfaces in close sealing contact with one another. To ensure that the sealing contact of the wearing surfaces can be maintained even with relatively long rotary kilns in all states (cold and hot), the sliding ring includes a plurality of ring elements which are concentric and telescopic.

Abstract: The invention relates to a drive arrangement for a rotating unit designed to be driven by a main motor or an auxiliary motor. A shift clutch is provided for arresting an overriding clutch in both directions of rotation. In this way the torques emanating from the rotating unit can be held or suppressed.