| 摘要 |
<p>1430108 Drying webs J & R WALKER PTY Ltd 10 May 1973 [30 May 1972] 22315/73 Heading F4G A drying apparatus comprises a housing 10, rollers 13, 14 each presenting a continuous cylindrical surface, i.e. one which is imperforate and free of protuberances and located within the housing for supporting a length of material, such as paper or board web 20, transported through the housing. There are means to introduce material to be dried into the housing and to guide the material to overlie at least a portion of the rollers while permitting the material during a substantial part of its travel over the rollers, to float on a vapour layer surrounding the rollers and out of direct contact with the rollers, and means for applying heat to the rollers sufficient to vaporize moisture contained within the material to be dried and to create a layer of vapour between the material and the portion of the periphery of the rollers which would otherwise be contacted at any given time by the material while wet. As shown, a feed roll 16 is located within the housing adjacent the inlet 11, and a spring-loaded tension roll 17 positioned at the exit end 12 of the housing maintains a constant tension in the web 20 and endless laterally spaced, driving wires 18 passing around the rolls 16, 17, rollers 13, 14 and wire tensioning rolls 19 are driven by a motor drive unit 21. Burners 22, fed with coal gas or liquid petroleum gas and located in combustion zones 23, 24, are orientated to direct a combustion flame against or towards the periphery of the rollers 13, 14 and hot air is transferred by blowers 29 through ducts 26 into hoods 27, 28; the temperature of the air is detected by sensors 30 and temperature control is effected by regulating gas flow to the burners and by admission of external, pre-heated air via conduits 31. Moisture laden air is extracted from the housing through a duct 32 and by a blower 33 and the hot humid gases expelled may be used to pre-heat air entering the conduits 31; alternatively, the air is removed at a number of spaced points adjacent each of the rollers 13, 14.</p> |
