ORDINARY REVERBERATORY FURNACES
located at the center of the hearth and the colder gases are drained
to it by sloping channels passing in this way underneath the plates
being heated. As the lower surface of the plates is exposed to the
hot gases, their heating is rapid and uniform.
Reiner, an engineer, conceived the plan of annealing or heating
plates by placing them in the furnace on their edges, and con-
structed the furnace shown in Fig. 106. This furnace did not
give satisfactory results because the hot gases circulated upon
the updraft principle, and for this reason the annealing of the
plates was not uniform. The idea was therefore abandoned.
The idea of Reiner may be conveniently utilized by reversing
the direction of flow of the gases to the downdraft method and
building the furnace with a solid roof, (*> placing the working doors
in the side wall.
XV. ORDINARY REVERBERATORY FURNACES FOR REHEATING
(With bar grates')
In coal-fired furnaces with the ordinary bar grate a temperature
of 1350° may be obtained in the firebox with a regulated air supply.
An air supply of 1.50 to 1.75 times the amount theoretically
required, according to the quality of the fuel used, will result in
such a drop of the temperature of the hot gases that it becomes
C1) Note by French translator.—In the plate annealing furnace, as designed
by Reiner, the plates were charged into the furnace through its roof and not
by doors in the side walls.