A device for the regulation of the temperature of the welding strips a permanent heating, in particular for welding of plastic sheets

摘要

1520556 Seaming non-metallic sheet material WINDMOLLER & HOLSCHER 11 Oct 1976 [5 Nov 1975] 42186/76 Heading B5K In apparatus for regulating the temperature of an electrically heated band 1 for welding plastics film, for indirectly determining the temperature of the band 1, a value corresponding to the voltage drop across the band and a current value from the heating circuit for the band are fed to a quotient former 19 of which the output is fed, as the existing value, to a regulator 9 which adapts the power of the heating circuit according to the departure of the existing value from a predetermined desired value. As shown, the band is connected to the secondary coil 4 of a transformer 6, the primary coil 5 of which is connected to the regulator 9 of which the input 10, 11 is connected to a voltage source. The current in the heating circuit is measured by an element 12 and fed by leads 13 to the quotient former 19 and the voltage drop across the band 1 is fed thereto by leads 14. The regulator 9 compares the existing value to the desired value and changes the transformer voltage according the difference. The temperature level can be set by a potentiometer 15 connected to the regulator 9.