Microwave Applications to Freeze Dehydration. Gaseous Breakdown vs. Electric Field Strength.

摘要

Food Freeze-drying cycles of 1/2to 1/10of the time required by conventional methods (radiant,conductive) appear feasible using microwave power. A major problem is corona breakdown,which occurs most readily under the pressure conditions of freeze-drying and causes deleterious effects on the food. The effects of pressure,temperature,frequency,gas composition,size and shape of cavity,electric field strength,and dielectric load are explained and interrelated in the region of interest of freeze-drying,using breakdown curves from the literature and derived by the authors. Experimental breakdown curves for air,water vapor,and carbon dioxide at 2450MHz are presented and compared with theory. (Author)