GB160940A - Improvements in apparatus for drying coated or enamelled paper, waterproofed cloth and such like - Google Patents

Abstract

160,940. Howden, C. F. Dec. 31, 1919. Drying fabrics and materials in long lengths.-In a stage drier for coated or enamelled paper, waterproofed cloth, &c. passed through a drying-chamber, the drying-air is heated in separate stages, the initial temperatures of which are progressively less stage by stage. Vacuum drying-pads are provided and a device for cutting out the supply of hot air in case of breakage of the web. The apparatus shown in Figs. 1 and 1<a> comprises a casing 1 formed with perforations 2 - - 5 above which air casings 6 - - 9 are mounted having inclined roofs and containing heaters 14 - - 17. Air-inlet pipes 18, 19 communicate with the casings 6, 9 and an outlet pipe communicates with the casing 1 between the casings 6, 7. The casing 1 communicates with the casings 7, 8 by openings 21, 22. The paper &c. passes from a coating-drum 44 through the casing 1 to a reeling-drum 45, and is dried by air drawn in by fans through the pipes 18, 19 and passing over the heaters and through the perforations 2-5 and openings 21, 22 to the outlet pipe 20. An additional drying effect is also produced by means of " vacuum pads " 31 within the main casing, each formed of two rollers 32, 33, Fig. 8, surrounded by a perforated endless band and enclosing a perforated chamber connected to a suction main. In a modified form of apparatus, the main casing is divided into three compartments each provided with an external air heater and external pipes from which air is supplied through nozzles projecting into the casing. Moist air from the first compartment is exhausted to atmosphere; the other compartments may utilize either open or closed circuit. Rollers maintain the web in contact with the vacuum pads. To prevent scorching in case of breakage of the web, a lever is provided, one arm of which comprises a cam 78, Fig. 4a, engaging a roller 77 connected by a chain 74 with a damper by which air may be caused to enter the first compartment either direct from atmosphere or through the heater; the other arm of the lever carries a roller normally supported by the web, breakage of which allows the cam to disengage the roller 77 and the damper to be shifted by a weight. In a further modification, two compartments are disposed side by side above a third compartment from which they are separated by a partition in which the vacuum pads are arranged; the web passes horizontally over and under the partition and in contact with the pads which are perforated above and below; air is directed from above through nozzles and from below through perforations in a pipe.