In addition to a destructor, there is at the Burmautofts depot a
"carbonizer" kiln, in which the sweepings of the vegetable markets are
burned into charcoal. The carbonizer consists of eight vertical cells,
in two sets or stacks of four, separated by a space containing two
double furnaces, back to back, there being a double furnace also at each
end of the eight cells. Each of the stacks of four cells is 15 feet
6 inches high; the ends and middle parts, forming the tops of the
furnaces, being 6 feet high. The block of brick work containing the
eight cells and furnaces is 26 feet 6 inches long and 12 feet 4 inches
wide at the floor level. Each cell is 3 feet 6 inches by 2 feet, and
about 10 feet deep, with a chamber below about 3 feet deep, into which
the charred material falls and is completely burned. The top of the
cells is level with the upper platform, and they are fed through a loose
cover, which is immediately replaced. Inside the cells cast-iron sloping
shelves are hung upon the walls so that their upper edges touch the
walls, but the lower edges are some inches off, so that the hot air of
the furnaces passes upward behind the shelves round the four sides of
the cell in a spiral manner, and out near the top into a vertical flue,
which conducts it down to the horizontal flue at the bottom, which leads
to the chimney. The charcoal is withdrawn from the bottom of the heating
chamber through a sliding plate 2 feet above the floor, and is wheeled
red hot to the charcoal cooler, which is a revolving cylinder, nearly
horizontal, kept cool by water falling upon it, and delivers the
charcoal in two degrees of fineness at the end. It is worked by a small
attached engine, supplied with steam from the boiler before mentioned.
Each cell of the carbonizer can reduce to charcoal 50 cwt. of vegetable
refuse in twenty four hours, but at Leeds not quite so much is put
through. The quantity of market refuse passed through six cells of the
carbonizer varies from 3 to 10 tons a day, and averages about 41/2 tons,