Patent GB-1311364-A (GB)
Title: Web drying method and apparatus for carrying out the same
IPC: F26B13/10
Filed: 1970-07-27
Abstract: 1311364 Drying wet webs of paper DOMINION ENG WORKS Ltd 27 July 1970 [18 Aug 1969] 36306/70 Heading F4G Mechanical energy derived from a gas turbine engine 10 is used to carry out one drying process on a wet web of paper, and thermal energy another. In Fig. 1, compressed air is led from the first section 17 of the turbine compressor 12 by means of a conduit 20, heat exchanger 31, and conduit 32 to a sonic vibration drier 30 (as disclosed in Specification 1,311,363) which comprises whistles 37 spaced along headers 33, the web 36 being supported on a drum 35. Air curtains are formed by slot nozzles 142 supplied with blended gas mixture by a conduit 41 leading from the heat exchanger 31 heated by the exhaust gases from the turbine 16. The inlet air to the compressor 12 is pre-heated at 19. Hot exhaust gas passes from the turbine 16 by way of conduit 22 and replaceable filters 55 to a series of gas injectors 57 each of which entrains fresh air from conduit 59 and return gas from conduit 60, dampers (not shown) controlling the flow in the conduits 59 and 60 to form a blended gas mixture part of which passes through conduit 61 to an impingement drier 40. The remainder of the mixture is passed via conduit 65 to a heat exchanger 67 (to heat fresh air drawn in through conduit 71 and passing to conduit 59), and then via the heat exchanger 31 (to heat the compressed air from the compressor 12) and the conduit 41 to the nozzles 142. In the drier 40, the web 36 engages a cylinder 45 (which may be perforated or steam-heated), and the gas mixture passes from the conduit 61 via a manifold 49 to impingement nozzles 50, and then passes via return conduit 75 to the injector 57. A filter system provided between the combuster 14 and the turbine 16, Fig. 3 (not shown), comprises a series of sintered ceramic cartridge filters in parallel and receiving the hot combustion products from the flame tube of the combuster 14. The flame tube is cooled by by-pass air controlled by an automatic temperature-responsive throttle, some of the by-pass air entering the flame tube and the rest passing around it and by-passing the filter system. The turbine engine fuel is chemically pretreated to reduce formation of combustion impurities. The turbine engine is coupled by a clutch to an electrical starter-motor/generator 24 producing electricity for dielectric or microwave heating and for driving components. In Fig. 2, the compressor-air pre-heater 19 may be replaced by variable air mixing system using recirculated hot air. A fossil-fuelled boiler 132 receives turbine exhaust gas by way of conduit 122, and supplies steam to drying drums 133. The boiler exhaust gas passes via filter 137 to injectors 156 supplying blended gas mixture via conduit 161 to a two-sided impingement dryer 140. The exhaust gas from the dryer 140 is returned to the injectors 156, and fresh air is admitted via a damper controlled air feed 178. Some of the gas mixture is passed by a conduit 170 to a preheater for fresh air. A conduit 177 having a throttle therein may be provided for an impingement drier, e.g. as shown in Fig. 1. The generator 24 supplies power to microwave generators 198 connected to opposed microwave transmitters 202 (to avoid wet streak problems). A perforated suction roller may be used instead of one of the drying drums 133.