58o CHAPTER XXVIII 



chambers formed by the interposition of copper plates b b, perforated with 

 a large number of holes about J-in. diameter ; in each plate is a disc valve, 

 d d, consisting of a disc of copper about 3 in. diameter and opening upwards ; 

 from each plate passes down a dip pipe, c c, about 9 in. long and 3 in. diameter ; 

 the top of the dip pipe projects about i in. above the copper plate and dips 

 into a cup which rests on the next lower plate. The rectifier is divided into 

 chambers by similar diaphragms, save that the five upper chambers are 

 separated from the others by an unperforated copper sheet n n, which has a 

 large opening at p and a receptacle at from which leads out a pipe m ; the 

 opening at p has a collar i in. high ; the five upper plates have no valves or 

 perforations, their object being to cause vapour to pass in a serpentine 

 direction. 



The method of working is as follows : — Wash is pumped into an overhead 

 tank (not shown) and flows down the pipe a a ; this pipe is continuous, and 

 emerging at the bottom of the rectifier is carried to the top of the analyser and 

 discharges the wash over the top diaphragm ; the wash flows down the, 

 analyser in a zigzag direction passing down the dip pipes, which are placed 

 as shown at alternate ends of the plates ; reaching the bottom of the analyser 

 the wash discharges through the pipe k. Steam is admitted at a pressure of 

 from 5 to 10 lbs. per square inch by the pipe ii, and passes upwards through 

 the perforations in the plates. The cups in which the dip pipes stand are 

 always full of wash, and acting as a seal prevent passage of vapour except 

 through the perforations. The dip pipes projecting an inch above the 

 diaphragms always keep this depth of liquid on the plates ; in case the vapour 

 is unable to pass quickly enough through the perforations, it can obtain a 

 passage through the valves d d. The steam in its passage through the wash 

 deprives it of its alcohol, and a mixed vapour of alcohol, water and other 

 volatile constituents passes out of the analyser by the pipe //, and is led into 

 the bottom of the rectifier. As the vapour meets the cold wash in the con- 

 tinuous pipe a a, it is condensed and at the same time heats the wash. The 

 water vapour and bodies of high boiling point, as well as some alcohol, are 

 condensed in the lower part of the still and fall down to the bottom, and are 

 continually taken away by the pipe h, called the " hot feints pipe." The 

 alcohol in great part condenses in the upper five chambers, and, falling down 

 on the plate n n, is received in the receptacle and taken away by the pipe m ; 

 this pipe leads to a refrigerator and thence to the spirit store. A pipe g 

 leads from the top of the rectifier and takes away the uncondensed vapour. 

 This pipe likewise passes through a refrigerator, and the condensed vapours 

 are collected and form the cold feints. At / / is a water coil, by means of 

 which the amount of cold feints allowed to be formed can be regulated. 

 The hot feints can either be allowed to mix with the wash or they may be 

 passed through a condenser and pumped to the top of the analyser. The 

 cold feints are collected separately, and, when sufficient have accumulated, 

 they are mixed with the wash and redistilled ; if pumped directly to the 

 analyser, owing to their low boiling point they volatilize with explosive 

 violence. 



The wash leaves the rectifier at a temperature of about igo° F. and is 

 completely exhausted of spirit in its passage down the diaphragms of the 

 analyser, the expelled vapour passing through the pipe //being at a tempera- 

 ture of about 205° F. to 210° F. The upper coil in the pipe a a is at the 

 temperature of the wash, and the temperature increases regularly on passing 

 down. The strength of spirit condensed in the upper five chambers can be 



