リンゴ加工に関する研究 : (第16報) 単一加熱器による果汁の予熱蒸発について

元データ 1971-10-25 社団法人日本生物工学会

概要

The recovery of the aroma of fruit juice rquires short-time preheating and evaporation.In the case of processing a large amount of juice, it is reasonable to use two separate heaters : one preheater in turbulent flow, and the other an evaporator. However, for consideration of plant cost and operation, it is desirable to use a single pass vertical long-tube (climbing-film) evaporator, preheated under laminar or transitional flow conditions.It has only qualitatively been observed that heat transfer performance is enhanced greatly when water, containing air bubbles, or juice flowing at lower speed is heated.The author measured the overall heat transfer coefficient in the preheating and evaporating sections by using a horizontal long-tube evaporator, and has developed a simple design procedure for horizontal long-tube evaporators which is also applicable to the climbing-film type.The design procedure.A) Water.(1) Preheating section(U_0)_<preheat> observed vs. h_i computed with the McAdams equation was used to calculate the preheating area or heat transfer rate.(2) Evaporating section The heat transfer rate in the evaporating section was obtained by using (U_0)_<evaporation>=2,200 (Kcal/m^2.hr.℃).B) Apple Juice.When apple juice was treated, the heat transfer rate was lowered by scaling, so (U'_0)_<preheat> and (U'_0)_<evaporation> were given by multiplying the above (U_0)_<preheat> and (U_0)_<evaporation> figures by the following factors.(1) When juice, from which solid material has been fully filtered by a centrifuge or a sieve made of silk, was treated in polished pipes : 0.9.(2) When juice, from which solid material has been fully filtered, was treated in unpolished pipes : 0.6-0.8.(3) When juice, from which solid material has been insufficiently filtered, was treated in polished pipes : 0.6-0.8.

著者

中山 悌三 朝日麦酒株式会社・中央研究所

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