GB1398845A - Removal of moisture from loose material - Google Patents

Abstract

1398845 Drying by electric fields WIRA 26 July 1972 [14 Aug 1971] 38242/71 Heading F4G Loose fibrous material is dried by a radio frequency electric field (1 MHz-100 MHz) in a compacted state, in order to obtain an even distribution of material across the field and a flow of air or gas through the material is created to remove moisture. The material may be dried in stationary batches or moved continuously. In Fig. 1, material supplied at 4 is compacted by plastics endless belt sections 6a and 16 and conveyed between electrodes 9 and 10. The material is guided by plastics side walls 12, side plates 18 and back plate 11. A fan 15 extracts hot air or gas through perforations (not shown), in the side wall(s) 12. Air or gas may be forced through the material by a blower (not shown). The time the material is between the electrodes 9 and 10 or the voltage applied to the electrodes 9 and 10 or the frequency of the application of voltage may be controlled by moisture content sensing means before or after drying. In other embodiments, the parallel belt sections 7 and 2 are inclined from the horizontal, and the lower belt is made electrically conductive so as to serve as the lower electrode; the electrodes of the Fig. 1 embodiment take the place of the vertical side walls 12; the parallel belt sections move vertically downwards and the electrodes may be as in Fig. 1 or comprise the side plates 18; the belt sections 2 and 7 move vertically downwards and converge. One electrode may be longer than the other. The material may be fed in compacted batches by a piston or plunger device, or the belts 1 and 6 may be driven intermittently. The material may undergo a preliminary drying with hot air.