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Abstract
The progress of
dielectric heating at radiofrequency (rf) heating
and drying technology in Europe over the last
20 years is reviewed. Certain already well-established processes like
plastics welding and wood glueing have advanced by
improved materials handling techniques and process control. The use of rf energy to post bake cereal and sugar based products
like biscuits (cookies) has become accepted both in new plant and as
retrofits. The textile industry has at last recognised the benefits of using
"volumetric" heat transfer to dry packages of yarn and other fibre
forms. Both of these examples have prospered because of a greater
understanding, by equipment manufacturers and by users, of the broader
aspects of heat and mass transfer rather than the purely electrical ones of rf generation and transmission. Recent developments in
simultaneous, application of radio frequency and conventional convective
heating in the same dryer or oven casing have resulted in a range of
equipment in which the major part of the heat is supplied by fossil fuels but
having a greatly improved performance due to the enhanced diffusion effected
by a small proportion of radiofrequency energy.
Key Words:
Rf processing, drying, European industry, penetration,
economics, dollar volumes, comparisons
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