Bulletin - Bureau of Chemistry Volume 1-12

Bulletin - Bureau of Chemistry Volume 1-12

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1883 edition. Excerpt: ...in rapid motion, we have as rapid evaporation in air heated only to 120, or in fact at zero, without artificial heat, as we have in boiling deeper masses of liquid on smaller surfaces heated by flames at 1,000 degrees of heat. A gallon of water sprinkled over a large surface evaporates more rapidly than a gallon of water placed on a red-hot stove, and more water is evaporated from the comparatively large surface of the pond by the roadside then by an intensely heated steam-boiler. " In attempting to evaporate saccharine liquids by air we can learn much from those engaged in evaporating fruit by hot air. The juices of fruits are not essentially different from cane juice; both contain saccharine substances, and vegetable acids, and albumiuous substances, and evidently both can be evaporated in the same way and under the same conditions. The sliced fruits are simply sponges which hold the liquid upon the trays, in thin masses, so that air can everywhere come in contact with large and moist surfaces. If the air is heated too much the fruit will be cooked or burned, for air can be made hot enough t0. melt lead. If the air is not sufliciently heated chemical changes occur in the fruit and the product is inferior. It is said the finest and whitest fruit is evaporated at a temperature of 140 to 180 degrees, or about the same temperature in vacuum pan sugar boiling. In evaporating fruits it is necessary to have large evaporating surfaces, rapid currents of air uniformly heated and properly distributed. " The fruit evaporators have met these conditions. They evaporate a bushel of apples weighing fifty pounds to five or six pounds of dry 'product. They evaporate this large proportion of water at comparatively low temperature, and...show more

Product details

  • Paperback | 344 pages
  • 189 x 246 x 18mm | 617g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236761669
  • 9781236761668