161 
Design and Construction of the Plants. 
The following is an average composition when working 
with anthracite at full load ; at no load the proportion of 
combustible gases is less : — 
Combustible 
'Hydrogen . H 2 
By volume 
15-6 
By weight 
1-2 
- 
n ri a n 
Carbonic oxide C 0 
. 20-8 
23*5 
gases 
^Methane. . C H 4 . 
1-2 
0-7 
Incombustible 
(YQ on o 
' Carbonic acid . C0 2 . 
. 6'5 
11-5 
Nitrogen . N 2 
55o 
67-0 
gdbCQ 
k Oxygen. . 0 2 
0-5 
0*6 
The above description of the chemical action is on broad 
lines only ; in reality it is very complicated. 
The arrangement of the firebrick lining of producers is 
an important matter, as it has a considerable effect on the 
formation of the clinker, on the liability of the clinker to 
adhere, and on the ease with which the clinker can be removed. 
Further, if the interior is difficult to get at, the lining with 
firebrick is likely to be badly done by the bricklayer, and 
there will be defective joints which will let in air and produce 
intense heat in the vicinity of these joints, and thus spoil the 
brickwork and produce clinker. In the hoppers, by means of 
which the fuel is fed into the furnace, there are variations in 
the design of the valves which are required for connecting the 
hopper with the furnace and with the outside, respectively, 
when fresh fuel has to be put in. This detail is important, 
as it is essential that no air should be able to find its way into 
the producer via the hopper, and this detail has therefore 
received considerable attention from designers. To maintain 
good gas, the depth of the fuel in the furnace should not 
vary sensibly, and for this object it is usual to have a storage 
bell, which also acts as a distilling chamber, from which the 
volatile constituents (in the case of anthracite) are gradually 
given off. 
2. A vaporiser , which may either be internal or external 
with reference to the shell of the furnace. The water is 
vaporised at atmospheric pressure by means of some of the 
sensible heat contained in the hot gases leaving the furnace, 
and in some cases by the heat of the fire. The vaporiser takes 
up a considerable percentage of the heat that would otherwise 
be wasted. In some producers definite provision is made for 
heating the air, and in such cases a further amount of the heat 
due to the combustion is saved. The heat thus recovered by 
the water vapour and the air constitutes the regenerative action 
of the suction producer. 
3. The scrubber , in which the gas is cleaned. Just before 
entering the scrubber the gas pipe is generally given a sudden 
change of direction with the object of getting rid of the heavier 
particles of dust. The scrubber also acts as a cooler and 
VOL. 67. M 
