Other types of indirect horizontal dryers, solid paddle and inclined flight are shown in Figures 6-4 and 6-5 respectively (courtesy of Tsukishima Kikai Co.).
Steam heated inclined flight dryer (Figure 6-5) originates from the jacketed dual-shaft screw conveyors. Both rotor and stator conduct heat. Biosolids are transported and mixed by solid (not heated) flights in a plug-flow fashion eliminating the need for paddles or scraper bars. The rotor speed is relatively high
Fig.6-5 INCLINED FLIGHT DRYER (Courtesy of Tsukishima Kikai Co.) 1)MATERJAL INLET, 2)EXHAUST OUTLET, 3)PADDLES. 4)INCUNED FLIGHTS. 5)VAP0R DOME, 6)DAM ADJUSTER, 7)C0NDENSATE OUTLET, 8)MATERIAL OUTLET, 9)HOLL0W ROTOR, 10)H0LL0W STATOR, 11)SUPP0RTS, 12)DRIVE, 13)STEAM INLET I
(30 - 45 rpm) which ensures good mixing and heat transfer. Typical product dryness is in 45 - 60% TS; SER is 10 - 20 kg H2O/m2 • hr. Granulation is poor (5 - 40 mm, with lumps). These dryers are also used in Japan for drying prior to incineration or for volume reduction.