GB1058185A - Method and apparatus for drying fibrous or foliate material - Google Patents

Abstract

1,058,185. Treating tobacco. K. KÍRBER. Oct. 7, 1963 [Aug. 23, 1962], No. 32402/62. Heading A2C. [Also in Division F4] Loose tobacco is dried to a uniform moisture content in a hot air current whose temperature is adjusted dependently on the required moisture content by blending hot air with cool air and simultanously varying the amount of heat imparted to the hot air. In one embodiment the air current is produced by suction from a fan or blower 13 and the ratio of cold air entering on the left of an intake 3, and of air heated by elements 4 is adjusted by a valve 6. An element 8 measures the temperature of the air in a duct 1 into which tobacco is supplied through a sealed feeder 7. The moisture content of tobacco separated out at 10 is measured by a device 19 associated with a regulator 20 controlling the elements 4 and valve 6 whereby if the moisture content is incorrect the admitted amount of cold air is altered to correct the temeperature in the duct to a value which is then maintained by adjustment of elements 4. Separated air passes along a passage 12 including a valve 5 and measuring element 15 which keep the total air throughput constant to a centrifugal separator 17 where residual material is collected, the air leaving through a connection 18. In a modification (Fig. 4, not shown) the intake 3 is connected to the pressure side of a fan or blower and comprises a pipe containing heating elements 4 and a by-pass pipe for admitting unheated air in a proportion controlled by a butterfly valve. Throughput is kept constant by a butterfly valve and measuring element at the intake entrance.