Continuous flow heat treating apparatus using microwaves

Electrical apparatus for heat treating particulate materials passing in bulk through the apparatus from an input end to an output end thereof, comprising:

• a conveyor pan elongated in the direction of travel of the materials;
• drive means operative to vibrate said pan and impart to it a motion to advance said materials in said direction of travel;
• an elongated cover over said pan having side and end walls closely spaced with respect to said pan;
• cover support means for supporting said cover above said pan;
• refractory heat insulation lining said pan, the insulation nearly filling the pan at a portion thereof near said output end but leaving a narrow shallow material conveying trough, the insulation partially lining the pan at a portion thereof near said input end but leaving a wider and deeper trough, and the depth and width of the insulation gradually increasing from the input end to the output end so that the trough becomes progressively narrower and shallower as it passes through the portion of the pan intermediate the input and the output portion;
• refractory heat insulation in the cover graduated to increase in thickness and width from the input end to said output end so that the insulation in the cover converges on the trough to form therewith an air space which becomes progressively smaller;
• electric heater means in the air space located in said input and intermediate portions and directed to heat materials in the trough;
• a microwave generator;
• and
• waveguide means coupled to the generator and extending through the insulation and directed to impinge microwave onto materials in the portion of the trough near said output end.