FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE. 



Tarious parts of the still; one in the spirit plate, a second at about the 

 twelfth coil of the rectifier, and a third on the pipe carrying wash to the 

 analyser. 



To use these stills to greatest advantage they must be worked with as 

 little sudden change as possible ; control is effected by regulating either the 

 flow of wash or steam ; in forms of stills where the wash is pumped to an 

 overhead tank, opening or shutting a cock or valve (the latter preferably) 

 controls the flow of wash. In other forms where the wash is pumped directly 

 through the coil a cock is fitted on the pipe, convenient to the distiller, and 

 connected to a second pipe leading back to the vessel from which the pump 

 draws. The amount of steam is regulated by a valve ; in general it is preferable 

 to control working by the flow of wash. 



The spirit should not be run from the spirit plate too rapidly ; if the latter 

 be emptied by opening the cook too much, a weak spirit collects and the cock 

 must be closed until the test bubbles show that spirit of the correct strength 

 is forming. The supply of wash and steam must be adjusted to each other ; 

 too little steam imperfectly exhausts the wash and an excess results in too- 

 much watery vapour passing over, giving a weak spirit. To allow the distiller 

 to see that the wash is properly exhausted, vapour from the lees is collected in 

 a separator, and carried through the supplementary refrigerator to a test glass 

 in which are bubbles floating in water and spirit 98 U.P. ; should either of 

 these sink it is certain that the wash is imperfectly exhausted. The advantage 

 of these stills over the common type of vat still lies chiefly in their economy 

 of steam. 



Approximate dimensions of a continuous still of the Coffey type working 

 up 1,000 gallons of wash per hour are here given, the letters referring to 

 sketch in Fig. 280. Rectifier R, total height 24 ft. x 8 ft. X 3 ft. ; analyser 

 A, total height 42 ft. X 8 ft. X 3 ft. ; number of chambers in both analyser 

 and rectifier 27; total length of pipe a a contained in analyser 416ft.; 

 diameter of pipe 2 in.; total surface of pipe 217 square feet; size of dip 

 pipes c in rectifier 4 in. X 9 in. ; and in analyser 1 3 in. x 3 in. ; diameter of 

 valves d, 5 in. ; diameter of vapour pipe/, 7 in. ; diameter of steam pipe ', 4 in. 

 diameter of hot feints pipes h, 1^ in. ; diameter of spirit pipe, 1 in. ; diameter 

 of cold feints pipe, 6 in. The still described is one constituted of wood and is 

 of rectangular section ; other forms of stills are built throughout of copper and 

 are often of circular section, the wash pipe being worm-shaped instead of 

 straight with U bends as in this case. 



The advantage of the Coffey still lies in its economy of steam, the 

 in-coming wash condensing and being heated by the alcohol and water vapour 

 distilled ; actually it consumes only about one-third the steam required for a 



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