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MUFFLE FURNACE FOR TEMPERING AND ANNEALING
STEEL AT THE PETROGRAD ARSENAL d>
THIS furnace supplies an interesting example of the application
of hydraulic laws to the computation of furnaces. An old furnace
of English construction with a cast-iron muffle and four dampers,
working with an updraft, was in operation at the Petrograd
Arsenal. It did not heat well and the heat was poorly distributed.
This furnace was replaced by a very costly one, which was con-
structed according to a German patent and also worked with an
updraft. The muffle was of brick. This furnace, notwithstanding
its complex design, could never be made to heat uniformly.
Upon the request of the superintendent of the forge, Professor
Groume-Grjimailo studied the conditions and recommended the
reconstruction of the old English furnace, in such a manner that
it would work on the downdraft principle. This was done according
to Figs. 133 to 136. The binding of the furnace was not altered.
After reconstruction the furnace worked perfectly. It was
practically impossible to detect any difference in temperature
between "the different portions of the large muffle (3600 X1000 X
100 mm) by the use of two Le Chatelier pyrometers. The tem-
perature of the muffle could be changed as desired, and it could
be made to vary between large limits (900° to 400°) by changing
the setting of the damper in the waste-gas flue.
A short calculation was made later concerning this furnace.
The computed consumption of fuel was 55 kg 80 per hour, about
640 kg per day. The actual consumption per day was 690" kg.
This estimate was based entirely upon the analysis of the gases
at different points within the furnace.
A cast-iron muffle was chosen for this furnace. A similar
(1) Revue de la Societt russe de Mttallurgie, /, pp. 4%3~426 (1913}. Revue
de Metallurgie, mai 1914 (p. 115, MS.).