Thawing frozen prod. esp. food with HF or UHF radiation - while prod. surface is cooled with electrostatic cryogenic spray

摘要

Internal heat is generated in the prod. by exposure to HF or UHF radiation while the surface of the prod. is kept cool with an electrostatic spray of a cryogenic liq. e.g. liq. nitrogen or "F reon R 12" (RTM). The radiation frequency is pref. ca. 25-50 MHZ or a few thousand MHZ. The process is pref. applied to the prod. as it is conveyed through a thermally insulated tunnel. Thawing is fast without producing surface burns. Undue drying and infection of the prod. with bacteria are avoided.