the measurements on the empty dryer had to be undertaken with
lower temperatures than normal. The air flowed upwards with
a velocity of 0.2 m s1 and a temperature of 48 C over the
complete width of the ‘air inlet’ at the return side of the second
belt. The ‘exhaust fans’ ventilated the exhaust stacks which
had a hydraulic diameter of 0.8 m. For all the ‘exhaust fans’ the
air was at a temperature of 49.5 C. It was assumed that the
walls of the dryer transferred a negligible amount of heat since
they were insulated with a 0.1 m layer of mineral rock wool.