This article was originally published in Electrochemical and Metallurgical Industry Publication of August 1907. Information within this article is therefore correct as of 1907. The publication of this material aims to provide historical insight on the subject and its place in industry.
The adjoining illustrations show the construction of the automatic still built by the F. J. Stokes Machine Company of Philadelphia. Still being paramount to the production of clean and pure distilled water. The raw water enters the lower end of the condenser, and in condensing; the distilled water is heated to boiling point by the time it reaches the overflow. A port connecting the still and condenser feeds this boiling water to the still and maintains a constant level, the action being therefore continuous.
Figure 1 - Sectional View of a Still
The distinctive feature of this still is the manner in which the steam generated in the still is conducted down through the condenser, raising the temperature of the feed water to such a point that the ammonia gas is released and driven off. A further advantage of this preliminary boiling is that very little additional heat is required to vaporize it.
Either steam or gas may be used for heating, and as the steam and water systems are entirely distinct, no oil from steam ever goes into the distilled water. All exposed iron surfaces are tinned to prevent corrosion.
An animal charcoal filter, through which the distilled water percolates on leaving the still, effectively removes all odor and gives the water sparkle and life. The still is made in four sizes for the treatment of 5, 10, 25 and 60 gallons per hour, respectively. The largest size is built in sections, and several stills of this size can be connected in series, thus increasing the total capacity to 300 gallons per hour for five stills in series.
Actual tests of the still of a capacity of 10 gallons per hour have shown that using steam equivalent to 100 pounds at a pressure of 15 pounds, and 125 gallons of condensing water, 10 gallons of distilled water were produced in 1 hour, showing that only 12 gallons of water are required for condensing, which is a very low value.
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