Heat exchanger with flexible plastic transfer surfaces - incorporating treatment on liq. side improving wetting, maximising transfer coefficient

摘要

The parent patent described a heat exchanger in which a horizontal pipe carrying a liq. is placed between the surfaces of a shell. These surfaces are sheets of flexible plastic and are suspended from the horizontal pipe. The pipe has two perforations allowing liq. to flow from it on to the sheets, and there is an outlet at the bottom of the shell, with a liq. seal. There are means of ereating a flow of gas along the outer surfaces of the shell. The improvement consists of treating the surfaces down which the liq. flows to improve the overall heat-transfer coefficient. The treatment gives the surfaces a critical superficial tension equal to or greater than the surface tension of the liq. in the same temp. range. The treatment is either to make the shell of cellulose acerate, or pref. to make it of ethylene polyterephthalate and to coat the internal surfaces with acrylic acid fired by radiochemical means.