GB1135238A - Power distribution system for microwave process chambers - Google Patents

Abstract

1,135,238. Drying. CRYODRY CORP. 22 March, 1966, No. 12611/66. Heading F4G. [Also in Divisions A2 and H5] Energy is radiated into a microwave heating chamber from substantially the whole length of a waveguide extending along the chamber. The waveguide has a number of slots, e.g. slots 57 in waveguides 54, forming an aperiodic array. The waveguide may be circular (as shown) or rectangular and, in the latter case, the slots may be in a broad or a narrow wall. Axial, transverse or oblique slots may be used. The slots may contain dielectric, hermetic seals or may be open, in which case the waveguide may be used to introduce a controlled atmosphere into the heating space. In the example shown, a product to be dried (e.g. onions, wood-chips, potato flakes, citrus powders, apples or chemicals) falls from inlet 39 to outlet 41 past slotted waveguides 54. In a further example (Fig. 1, not shown), products (18) to be heated pass on a conveyer (19) through a conductive microwave heating tunnel (12) along the top of which a slotted waveguide (23) extends parallel to the axis of the tunnel. Transverse wave reflectors (28) extend from the top of the tunnel between the slots. Each end of the tunnel has an annular water conduit (17) with a dielectric inner wall (14) for preventing escape of wave energy.