BAIRD &.TATLOCK (LONDON) LTD. 



DESCRIPTION OF THE STILL. 



(See Diagram.) 



The water to be distilled is boiled in an open pan, A, furnished with an overflow pipe, B, at the side. The 

 main condenser consists of a double cylinder of block tin ending above in a dome, which is shown in section by 

 . the lines c, D, E. These cylinders form a pocket, D, at their lower end, in which water condenses, and from which 

 it is led away by the pipe G. Round the outer surface of the main condenser, at a short distance above the pocket, 

 there is provided a series of holes, F, through which the vapour which is not condensed in the pocket passes into an 

 annular chamber, H. This is connected at one side to an escape pipe K, which serves as an auxiliary condenser, 

 being surrounded with a water circulation jacket, L. The main condenser is jointed by means of a water-seated 

 joint to a copper cylinder, M, which is open at the bottom, and stands in the open pan, A. The spray arrester, N, 

 consists of a short cylinder furnished with suitable slits, v, through which the steam issues tangentially, and within 

 a cap, N, which deflects the steam downwards. The cyclonic action set up by the tangential flow causes spray to 

 be deposited and to run back into the pan. The main condenser is jacketed by an outer cylinder, p, which is 

 covered with a loose lid, Q, in order to arrest the escape of steam. Condensing water is supplied by a funnel, R. 

 The quantity required is very small (60 to 90 c.c. per minute, according to the temperature of the supply), and 

 it escapes by an overflow, s, and is delivered by a pipe, T, as feed-water into the pan, A. 



In operation the flow of condensing water into the funnel, R, is so regulated that the temperature of the 

 main condenser varies from 100 at the top to about 95 at the bottom. Under these conditions, if the water 

 in the pan is vigorously boiled with a suitable ring-burner supplied with gas at 2 inches water-pressure, about 

 two-thirds of the vapour is condensed in the main condenser. The surplus one-third passes through the holes F 

 into the annular ring H, and is condensed at K. 



The flow of gas and water require careful adjustment, which is soon learned by experience. If, for instance, 

 with full gas supply, excess of condensing water is supplied through R so that the temperature at the bottom of 

 the main condenser falls below 90, the whole of the vapour will be condensed in the main condenser, and there 

 rill be little or no fractionation. If, on the other hand, too little condensing water is supplied, there will be little 

 condensation in the main condenser, and the bulk of the water will be condensed in K. With a steady gas-pressure 

 and water-pressure, however, the still maybe left to itself through the night without any interference. The water 

 from the condenser L should not be used to feed the funnel R, as the temperature equilibrium then becomes unstable. 



5288* Hartley s Still, for the preparation of pure distilled water for conductivity experiments, 



agned by Messrs. Hartley, Campbell, & Poole, Balliol College, Oxford. The still 



consists of copper vessel A, 10 litres capacity, lined inside with pure tin. Condenser 



tin throughout, with glass condensing vessel T. Price of still complete, as 



ngurea, with burner and stand 



(See Journal Chemical Society, 1908, p. 428.) 



5288 



3 3 



