| 摘要 |
940,946. Drying foams of food &c. A. I. MORGAN, L. F. GINNETTE, and R. P. GRAHAM. March 30, 1961 [April 5, 1960], No. 11665/61. Heading A2D. [Also in Divisions B1 and F4] A foamed product formed from a solution or dispersion of a solid material in water is applied to a perforated surface and a gas is forced in through the perforations at a sufficient velocity to displace that portion of the foam overlaying the perforations, whereafter the foam is dried. As shown in Fig. 2, a foamed product is supplied at 4 on to a moving perforated support 1 which travels over a nozzle 3 through which a current of gas is fed at a sufficient velocity to displace the foam overlaying the perforations. The foam is then carried through a drying apparatus 16, operated with a hot gas supplied at 18 and withdrawn at 19, and a cooling apparatus 20, and the treated foam is detached from the support 1 by blades 25, 26. A modified apparatus is described (Fig. 3, not shown) in which the dryer 16 is divided into two sections through which the drying gas passes first in the same direction as the foamed product and then in the opposite direction. The dryer may include supplementary heating means. In the apparatus shown in Fig. 4, the foam is supplied at 43 to a perforated tray which passes over a gas blower 45 and thence to a duct 48 up which the trays are lifted, drying gas being supplied both at 49 and at 51 and the gas leaving the duct 48 through the aperture 50. The trays are withdrawn at 47 and the treated foam passes over a cooler 52 and is collected at 55. More than one aperture 50 may be provided in the duct 48. The material to be treated may be converted into a foam by incorporating air or other gas into the material, optionally after preliminary concentration or addition of a surface-active material and (or) a hydrophilic colloid, many surface-active agents and hydrophilic colloids being specified. Many materials which may be treated are also specified, including fruit, vegetable, meat, fish and milk products, food for animals, tanning agents, vitamin preparations and enzyme products. The gas used for the preliminary treatment of the foam on the perforated surface is preferably air, but reference is made also to the use of nitrogen, carbon dioxide, nitrous oxide, helium, propane, n-butane, isobutane, dichlorodifluoromethane, trichloromonofluoromethane or monochlorotrifluoromethane. The preferred drying gas is air, but nitrogen, carbon dioxide, helium or combustion gases may also be used.
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