Apparatus for cooling dust or finely granular bulk material

In an apparatus for cooling explosive-prone dust or finely granular bulk material, having a vertical cylindrical cooling jacket, an externally cooled cylindrical surface of which is fed with the material to be cooled from inside of the cooling jacket by means of an annular continuous conveyor worm which conducts the material upward and which by sufficient rotation provides centrifugal force which presses the material against the cooled cylindrical surface consisting a heat exchange surface, the conveyor worm which is rotatable around a central axis being operatively rotatably driven by a motor so as to provide the sufficient rotation providing said centrifugal force, the improvement in the apparatus comprising

• a hollow body having a continuous cylindrical surface, the hollow body being closed at its ends and disposed inside the cooling jacket, and the conveyor worm is arranged on the continuous cylindrical surface of the cylindrical hollow body, the hollow body occupies the greatest part of the inside of the cooling jacket thereby defining therebetween a relatively small annular region, and is rotatably driven by the motor, and wherein
• the annular continuous conveyor worm is disposed inn said small annular region and is coated with a non-sparking material at least on a potential contact surface thereof facing the cooled cylindrical surface of the cooling jacket preventing sparks.