GB474095A - Improvements in or relating to methods of and apparatus for drying inked impressions - Google Patents

Abstract

474,095. Drying printed sheets. STEVENS, A. H. (Steel Engravers Appliance Corporation) July 4, 1936, No. 18626. [Class 34 (ii)] Inked impressions, particularly those printed from steel engraved plates, are dried by subjecting them to radiant heat while maintaining the atmospheric temperature on all sides of the sheets constant by circulating the air surrounding the sheets in an enclosed circuit. The sheets are carried through an oven 10 by a conveyer-band 29 and pass under pairs of electric heaters 35, 39 partly enclosed by curved reflectors 45. The heaters 39 are maintained at a temperature of about 600‹ F. and form the main source of heat for the oven and for drying the sheets, while the heaters 35 are controlled by a thermostat 36 so as to maintain the oven at between 150 and 250‹ F., according to the setting of a switch 38. The air inside the oven is kept in circulation by means of a fan 52, the outlet 54 of which is divided and communicates with a passage 53 between brackets 42 from which the heaters and the reflectors are supported. The air is thus forced down on to the centre of the sheet and then outwards towards the edges thereof. The walls of the upper portion of the oven are insulated so as to bring about an even distribution of the heat. After drying, the sheets travel in a vertical path to a receiver 95. In a modification, the fan is wholly outside of the oven, and air is admitted to the intake pipe to humidify the air inside the oven ; also, a radiator is provided in the outlet from the fan for regulating the temperature of the air, and a vent tube is provided for diverting some of the air so as to reduce its velocity.