Abstract: A fan apparatus is disclosed having a first fan and a second fan, both of which are centrifugal fans. Impellers of the first fan and the second fan can be located adjacent one another and adapted to rotate in opposite directions. A first outlet opening (ot1) provided on a housing of the first fan can be located relative to a second outlet opening (ot2) provided on a housing of the second fan such that a flow pattern of the first fan overlaps at least partially with a flow pattern of the second fan when viewed from a direction of a rotation axis of an impeller of the first fan.

Abstract: A fan apparatus is disclosed having a first fan and a second fan, both of which are centrifugal fans. Impellers of the first fan and the second fan can be located adjacent one another and adapted to rotate in opposite directions. A first outlet opening (ot1) provided on a housing of the first fan can be located relative to a second outlet opening (ot2) provided on a housing of the second fan such that a flow pattern of the first fan overlaps at least partially with a flow pattern of the second fan when viewed from a direction of a rotation axis of an impeller of the first fan.

Abstract: The employed feed element in a grinding body feed apparatus of a grinding mill is the grinding bodies supply tank proper, in which the grinding bodies are charged from a ball hopper or storage. In connection with the supply tank, there is provided a grinding bodies discharge element, by means of which the grinding bodies are conducted to a duct serving as a feed chute and leading to the grinding mill, and via said duct, to the grinding mill proper. The opening and closing of the supply tank is carried out by external, opposing control elements that encircle the drum element of the supply tank in relation to its frame. By means of the feed device, it is possible to feed one ball at a time to the mill, in which case a correct number of balls can be supplied.