584 



, COAL 



strap and pulleys x. These agitators serve to increase the action of the washing fluid 

 contained in the tube I, by which the gas is washed previous to passing through the 

 dry-lime purifier. 



The mode of operation is as follows : the gas to be purified is admitted through 

 the pipe q, to the chamber r, from whence it passes along the tube /, as shown by the 

 arrows, to the chamber s ; it then rises into the chamber t and enters the tube c, along 

 which it passes in the direction shown by the arrows, whence it may be conveyed, 

 through the pipe v, to the gasometer. 



It will be apparent, as the gas passes along the tube Z, containing the agitators w, 

 which are caused to revolve speedily by the motion given by the straps and speed 

 pullej's x, that the washing fluid, which is passing regularly through the syphon y, 

 and running into the chamber , and along the tube I, into the chamber r, keeping the 

 level as shown by t ; 6, is caused to be revolved into a centrifugal motion round the 

 tube /, by the two paddles z, placed upon the circular perforated plates, secured ;.pon 

 the shaft m, which are set to an angle, thereby causing a counter-motion from left to 

 right of the tube /, and causing the washing fluid to be wrought into a complete spray 

 amongst the gas, whereby the heavier parts of the impurities are carried away more 

 effectually than by any other washers in use. 



The gas then enters the chamber t through the tube c, passes along the coils or 

 threads of the worm or screw d, and as the cross pieces d' are set to an angle, as 

 shown in fig. 1043, the lime is raised from the lower to the upper part of the tube c, 

 and then drops down to the gas that is making its way towards the openings c 2 ; con- 

 sequently, the lime and the gas become most intimately mixed, whereby the lime is 

 made to absorb a much greater proportion of the impurities contained in the gas than 

 is effected by the dry-lime purifiers usually employed, in which the lime is supported 

 on stationary trays. The lime dropping into the tube c, from the hopper a, is worked 

 gradually towards the chamber i, into which it drops. The speed of the screw or 

 worm d, the number of threads upon it, the length and diameter thereof must be 

 made to suit the quantity of gas to be purified per hour. The lime which drops into 

 the chamber t, may be removed therefrom through the man-hole w. Mr. Lees states 

 that a considerable saving is effected in the lime, owing to each particle or atom being 

 kept in motion, and falling repeatedly through the gas in its passage from one end of 

 the tube to the other, and that there is also a great saving in labour. 



Another form of wet purifier, which might also be advantageously used as a 

 scrubber, or as a naphthaliser, has been invented by M. Colladon of Geneva, and 



1044 



is now in use in the gas-manufactory of that city. This apparatus, as shown in 

 vertical section in fig. 1044, consists of a sivtioii <>1 a very obtuse cone A' the anjrlc <>f 

 inclination of which is 164. Its upper and smaller end is joined to a metal cyliiulcr A, 

 placed on the same axis as A', and about its own diameter in height. At top it is closed 



