Electrically-heated dryer and cooler for granular materials and sludges - has heated rotors attached to rotating shaft in contact with material being dried and are divided into zones each operated at a different temperature

摘要

A new continuously-operating contact dryer (I) for granular materials and sludges has heated rotors (10) attached to a rotating hollow shaft (9). The novel feature is that the rotors are electrically heated and are divided into at least two heating zones (13, 14, 15), the discs in each zone being operated at different temperatures. Also claimed is an apparatus for carrying out the procedure, having a housing (2), an inlet (3) at one end wall (4) and an outlet (5) at the other end (6). The rotors are provided with electric heaters (11) individually supplied (16, 17. 18) via slip rings (19, 20). USE/ADVANTAGE - Especially for drying sewage sludge. The rate of heating can be adjusted exactly to the requirements of the material being dried, investment cost is reduced and problems with the emission of gases are eliminated.