Lime-Sulphur C oncentrate. 39 
STORAGE TANKS. 
Storage tanks for the cold water and for the prepared concentrate 
may be of concrete, wood, or metal. 
The water-supply tank may be above, level with, or below the 
ground surface. The elevated tank has the advantage of gravity 
drainage, but on the other hand it requires that substantial sup- 
ports be provided. Cylindrical wooden tanks are often used for the 
water supply. These are usually elevated and supported on wooden 
posts. Elevated concrete tanks require properly designed walls or re- 
inforced columns, the number and size depending upon the capacity 
and dimensions of the tank. The tank, too, should be reinforced and 
the walls should have a minimum thickness of 6 inches. 
Storage tanks for concentrate are frequently built of concrete. 
They are usually placed below ground so that they may be supplied 
from the filter tank by gravity. Concrete underground storage 
tanks: are used because they are comparatively easy to construct. 
The bottom and walls should be poured at one time so that there will 
be no joint through which leakage might occur. Such tanks, espe- 
cially if of large size, should be reinforced to prevent cracks due to 
settlement or earth pressures. The top may be of concrete or of wood. 
The floor of the house of the plant shown in Figure 20 forms the top 
of the storage tank, access to the inside being through a manhole. 
Concrete work of this kind requires careful design and placement of 
the reinforcement, and provision must be made for additional sup- 
port for superimposed: loads such as the cooking and filter tank in 
Figure 20. 
FURNACE AND FLUE. 
Brick is perhaps the best material of which to construct the fur- 
nace, which should be equipped with a cast-iron grate and cast-iron 
fire and ash-pit doors. The use of fire and ash-pit doors is, of 
course, not absolutely necessary, but they afford far better regula- 
tion of the fire and make for more efficient operation. If the air 
supply necessary to combustion is controlled, economy in fuel con- 
sumption is possible. The top of the grate should be about 15 inches 
below the lowest part of the bottom of the cooking tank, and the 
ash pit should have a depth of about 9 inches. It is well to ex- 
tend the furnace about 12 inches beyond the front end of the cooking 
vat. This aids cooking by bringing the fire nearer the front end 
so that the entire length of the vat is subjected to the greatest heat 
of the fire. The furnace construction should be practically air tight 
to assure a good draft. Lime mortar may be used in laying the brick 
and in bedding the cooking tank, but cement mortar is preferable. 
If the hot gases of the smoke flue are to be utilized in heating 
the water, as in Figures 9 and 28, the flue should be run under the 
water tank, and at this point should be as wide as the tank and not 
less than 6 inches deep. It should be built of not less than 20-gauge 
galvanized iron and should be covered with insulating material to 
prevent or lessen the radiation of heat. The top of the flue should 
be omitted under the water tank so as to reduce the amount of metal 
between the gases and the water as much as possible. All wood 
surfaces that are less than 12 inches from the smoke pipe or flue 
should be protected with insulating material. 
