GB704364A - Method and apparatus for treatment of objects with ultra short waves - Google Patents

Abstract

704,364. Electric heating by high frequency fields. BLAUPUNKT-WERKE GES, Sept. 7, 1951 [Sept. 7, 1950], No. 21147/51. Class 39 (3) A method of heat treating objects with ultra-short waves utilizing a high frequency generator comprising a frequency determining generator circuit and a loading circuit coupled therewith, and including a condenser having the treated material forming at least a part of its dielectric, wherein at the start of the treatment, when the material is cold, the circuits are mutually adjusted to give a high output from the generator, and wherein changes of the reactance, dielectric constant, or angle of loss of the material during treatment automatically alter such adjustment to give a correspondingly lower output from the generator, but without substantially altering the frequency of the generator circuit. Apparatus for the permanent waving of the hair, Fig. 3, includes a high frequency oscillator which feeds a tank circuit comprising an inductance 6 and capacitor 7. The tank circuit is coupled to a secondary winding 9 including a capacitor 10, which secondary winding is connected to the input of a cable 11 feeding heating electrodes 12, 13. The electrical data of the loading circuit is arranged so that the output voltage of the cable is practically independent of the load impedance, and to keep a substantially constant frequency of the generator during the heating process the reactive power of the generator is large.