Patent GB-453831-A (GB)
Title: Improvements in or relating to the manufacture of films and foils from plastic masses, and products coated with such masses
IPC: B29D7/00
Filed: 1935-03-12
Abstract: <PICT:0453831/IV/1> <PICT:0453831/IV/2> In apparatus for making films or foils from plastic masses containing volatile solvents, such as compositions of cellulose derivatives, gelatine, rubber, natural or synthetic resins, or for obtaining products coated with such plastic masses, there is provided an enclosed drying machine, means including a fan or equivalent device for driving a current of air through the machine to remove evaporated solvent, a device for setting the output of the fan in accordance with the solvent or product being formed, and means, interlinked or interconnected with the power device for operating the drying machine, for separately regulating the fan according to the rate of output of the product from the machine. The air current may be heated and the supply of heat may be regulated in accordance with the rate of flow of the air current. This may be effected automatically.  The drying machine may also be provided with heating devices which may consist of pipes through which hot fluid is circulated, and regulating valves.  If desired, controlled electric heating devices may be used.  The device for heating the air current may be in advance of the drying chamber or in the chamber itself and if desired the devices for heating the air current and the drying machine may be combined. As shown in Fig. 1, a drum or band machine is enclosed in a chamber 1.  Air is circulated by a blower or fan 4. It is heated by passage through the device 6 which is supplied with hot water, steam, or oil, or other flud from a heater 7 through pipe 8, the fluid being returned to the heater.  The flow of heating fluid in pipe 8 is regulated by a valve 9 operated by a temperature control device 10 associated with the air duct 2.  The device 10 maintains air passing through duct 2 at a constant temperature.  The drying machine is separately heated by fluid from the boiler 7 passing through pipe 11 and regulated by a valve 12 operated by a temperature control device 13.  The device 13 may be associated with any part of the drying apparatus such as the region adjacent the carrier for the film-forming solution or adjacent the air outlet.  The solvent laden air is passed through condenser 14 for recovery of solvent.  The speed of the blower 4 is regulated by a p  lever 16 set to any predetermined position 17 in accordance with the kind of product being formed.  The blower is also regulated by linking the devices which drive the blower and which drive the drying machine.  Instead of lever 16, a similar device regulating the position of baffles in the air ducts but not affecting the speed of the fan, may be used. As shown in Fig. 2, air from the blower 4 passes directly to the enclosure 1.  The speed of the blower is set by lever 16 and the drive is also interlinked with that of the drying machine.  Heating fluid is circulated from boiler 7 through a single heating circuit in enclosure 1 by way of pipe 11 and regulated in accordance with the air delivery by direct control of valve 21 by lever 16.  A temperature control device 20 also operates valve 21 and opens it above its minimum position so as to provide the further heat required for evaporation.  Specification 428,663 is referred to.ALSO:Apparatus for removing solvents in the production of films, foils, or other products made of or coated with plastic masses such as compositions of cellulose derivatives, gelatine, rubber, natural or synthetic resins, comprises an enclosed drying machine, means including a fan or equivalent for forcing air through the machine, a device for setting the output of the fan in accordance with the solvent or product being formed, and means interlinked or connected with the power device for operating the drying machine, for separately regulating <PICT:0453831/III/1> <PICT:0453831/III/2> the fan according to the rate of output of the product from the machine.  The air current may be heated and the heat supply regulated in accordance with the rate of air flow.  This may be effected by automatic control.  The drying machine may be provided with heating devices consisting of pipes through which hot fluid is circulated, and regulating valves.  If desired, controlled electric heating devices may be used.  The device for heating the air current may be in advance of the drying chamber or in the chamber and if desired the devices for heating the air and the drying machine may be combined. As shown in Fig. 1, a drum or band machine is enclosed in a chamber 1, and air is circulated by a blower or fan 4.  The air is heated by the device 6 which is supplied with hot fluid such as water, steam, or oil, from a heater 7 through pipe 8, the fluid being returned to the heater. The flow in pipe 8 is regulated by valve 9 operated by a temperature control device 10 associated with air duct 2.  The device 10 maintains the air passing through duct 2 at constant temperature. The drying machine is separately heated by fluid from heater 7 passing through pipe 11 and regulated by valve 12 operated by a temperature control device 13.  The device 13 may be associated with the region adjacent the carrier for the film-forming solution or adjacent the air outlet.  The solvent-laden air passes through condenser 14 for recovery of solvent.  The speed of the blower 4 is regulated by lever 16 set in any predetermined position 17 in accordance with the kind of product being formed.  The blower is also regulated by linking the devices which drive the blower with those which drive the drying machine.  Instead of lever 16, a similar device regulating the position of baffles in the air ducts but not affecting the speed of the blower may be used.  As shown in Fig. 2, air from the blower 4 passes directly to the casing 1.  The speed of the blower is set by lever 16 and the drive is also interlinked with that of the drying machine.  Heating fluid is circulated from heater 7 through a single heating circuit in enclosure 1 by way of pipe 11 and regulated in accordance with the air delivery by direct control of valve 21 by lever 16.  A temperature control device 20 also operates valve 21 and opens it above its minimum position so as to provide the further heat required for evaporation. Specification 428,663, [Group IV], is referred to.