GB900390A - Improvements in or relating to the cooking of foodstuffs by radio frequency dielectric heating - Google Patents

Abstract

900,390. Heating biscuits by electric fields. RADYNE Ltd. June 18, 1959 [June 24, 1958; Aug. 13, 1958; Jan. 5, 1959], Nos. 20225/58, 26039/58 and 388/59. Class 39 (3). In a method of baking biscuits or other flat, thin articles of foodstuffs, the article is heated by heat transfer in a conventional baking oven 10 and then, with the interior of the article still incompletely baked or having a higher moisture content than normal, is transferred to a dielectric heating oven 18 in which the direction of the electric field and the arrangement of the article in the field are such that a substantial component of the electric field passes along the incompletely baked or moist interior of the article. . In the arrangement shown the biscuits pass through the oven 10 on a steel conveyer 12 and are transferred to a fabric belt conveyer 14 which enters and leaves the dielectric heating oven 18 through interference suppression and safety tunnels 16 and 20. The biscuits are then transferred to a cooling conveyer 22. In one electrode arrangement, Fig. 2, the output coil 24 of a generator is connected to a balanced system of two units 26 and 28, each having four parallel rod electrodes 30 arranged above the conveyer belt 14 carrying the biscuits 36. Rod electrodes 32 below the belt are arranged in staggered relationship to the electrodes 30 and are connected through a plate 34 to the frame of the apparatus. Alternative electrode arrangements comprise a system of parallel rods arranged either above or below the conveyer belt and lying either transverse (Fig. 4, not shown) or at a small angle (Fig. 5, not shown) to the direction of movement of the belt, alternate electrodes being connected together to form two sets which are connected to the two terminals of the generator. With these electrode arrangements a single canvas conveyer can be used to pass the biscuits through both ovens 10 and 18. With the conveyer system shown in Fig. 1, conveyer 12 can be run at a higher speed than conveyer 14 thus causing the biscuits to be stacked on end along the conveyer 14 either obliquely or vertically. The electrode system can then be two plates, one above and one below the conveyer 14.