GB1035053A - Drying system - Google Patents

Abstract

1,035,053. Drying systems. DOMINION TAR & CHEMICAL CO. Ltd. July 15, 1963 [July 20, 1962], No. 27916/63. Heading F4G. The drier section of a paper-making machine comprises steam-heated cylinders 5, 9 between which a relatively constant heat differential is maintained by means comprising pressure control valves 16, 17 in a main steam supply line 14 controlled by pressure controls 19, 20 respectively which are connected to lines 18, 15 supplying the steam to the respective cylinders. Pressure in the drum 5 forces steam and condensate up a syphon 8 for passage through a pipe 21 with a long, restricted orifice 22 to a flash tank 24 from which a predetermined level of condensate is withdrawn to the steamgenerating boiler and flashed steam from the top of the tank is fed through a line 27 to the line 15 for use in the cylinder 9. Pressure in the cylinder 9 forces condensate out of syphon 12 either through a valve 29 to a condensate header 30 or through a valve 31, steam trap 32 and valve 33 to the header 30 in which the condensate is partially cooled by spray nozzles 38 fed with cooled condensate. The condensate passes through a line 39 to a cooling heat exchanger 40 and a cooled condensate tank 44 from which cooled condensate at the bottom of the tank is fed through a line 46 and valve 47 to the spray nozzles 38, excess condensate passing through a valve 50 to the boiler, and a vacuum being maintained at the top of the tank 44 by a vacuum pump 53. More than one cylnider may replace each cylinder 5 and 9.