Paul Schatzberg U. S. Naval Engineering
Ex~erimentStation Annopolis, Maryland
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A Gar Saturation Apparatus
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The need to saturate air with water or, in gencral, gases with liquids frequently arises in the laboratory. A simple apparatus for doing this is illustrated in the photograph which shows dimensions and eoustmction features. The apparatus shown was made from clear plastic tubing and nylon fittings. A somewhat simpler construction than that shown uses two number 7 rnhber st.oppers to close the ends of the large tube. Each stopper was fitted with a right angle bend of glass tubing. The evaporator section consisted of a stiff metal strip of coarse screen material (1 X 41/2 in.) provided with three or more slots, each of which can accept four or five absorbent (nutrient) pads. These pads are cut so that the portion above the metal screen just clears the inside of the tube. The pads are held apart by strips cut from other pads. The lower portion of each pad fits into slots in the metal screen, projecting below it about in. When cut in the described manner, each absorbent pad should look like a two-dimensional projection of a mushroom. The removable press fit cap on one end of the tube holds the screen firmly in place. Water or another volatile liquid is introduced into the tube nntil its level reaches the bottom of the screen. This wets the lower ort ti on of the absorbent ads and. by capillary action, the rest of the pads. Air or another
gas can be passed through the apparatus from either end. The entire apparatus is easily placed in a constant temperature bath. The saturated gas emerging from the apparatus can be quickly passed through other equipment situated in the same bath. The apparatus can be used singly or in series of two. By varyiug the bath temperature and gas flow rate, various levels of saturation can be obtained. Since the gas being saturated does not hltbhle through the liquid, a technique which is freuuentlv used. an undesirable aerosol mist is not formed.
Volume 40, Number 5, May 1963
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