is 10 to 40 per cent in excess of the nominal capacity. When
crane and ladle capacity is available this excess can be turned
into output; otherwise it may be troublesome. The other uncer-
tain factor is in the checker brickwork itself, the way it is set
and its material, the space allowed for the passage of gas and air
and thickness of the brick.
A number of more or less empirical rules have been proposed
for arriving at the volume of checker or regenerator capacity.
A. Consett makes the total regenerator volume 2 cu m per tonne
(70 cu ft), and makes the air chamber 10 per cent larger than the
gas chamber, for furnaces designed to make four melts per twenty-
four hours. In Notes et Formules it is stated that " for slow
furnaces the empirical relation between the volume of the regen-
erator and the charge of the furnace in tonnes is 0.8 cu m (28 cu ft)
to 1.3 cu m (46 cu ft) per tonne; and for fast working furnaces
from 53 to 64 cu ft per tonne." H. H. Campbell says from 50
to 100 cu ft per tonne of melting capacity. Gruner says 50 to
70 kg of checker brick per kilogram of coal burned per reversal.
Told suggests 6 cu m or 2850 kg of checker brick per cubic meter
of air pe?r second per 100° C. rise in temperature. Another sug-
gestion is the provision of 50 sq m (537.5 sq ft, of checker surface
per tonne (metric) of coal per twenty-four hours.
In Euchene's investigations on the carbonizing of coal he
developed a formula for the heat-storage capacity of checker
brickwork which may be stated as follows:
Qo' = 0.20H-0.000062*2,
in which Qo* = kilogram calories per kilogram of checker brick
between zero and t degrees C.; and in which t = temperature to
which the brickwork is raised, degrees C.
Breslauer cites the regenerator data of a number of furnaces,
giving the number of cubic meters of regenerator per ton of steel
His figures are given for a number of different plants as follows:
CUBIC METERS OF REGENERATOR PER TON OF STEEL PER HOUR
Krupp, large.. .. 18.32
Krupp, 3 ton.... 36.00
Terre Noire..... 30.00
Steelton, Pa___ 37.45