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Full text of "The Flow Of Gases In Furnaces"

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Blocking up of the checkerwork by dust deposits occurs
progressively, and a number of schemes have been tried for increas-
ing the time between clean-outs. This dust collects upon the
upper portion of the checkerwork and causes more trouble in the
air checker than it does in the gas, for the reason that the gas
usually enters the regenerators under pressure and this pressure
can be increased to overcome increased resistance. The air,
however, enters the checker under atmospheric pressure, and its
flow is induced by the chimney effect caused by the heat it absorbs
acting through a vertical height equal to the distance from the
bottom of the checkerwork to the port. It naturally follows that
increased resistance will have a considerable effect in reducing the
air supply, and it is frequently necessary to put a fan on the air
supply after 400 to 500 heats. Running the gas through the air
checkers has been the subject of a patent, the idea being based
upon the reducing action of the gas, but this deposit contains very
little iron ore when there are adequate cinder pockets. The
composition of this deposit at the Donetz-Jurjewka works was:



Additions and limestone, per cent ..............
	26 0
	37 0

Furnace lining, per rent ....... ..................
	0 8
	1 5

Cinder per cent
	28 2
	16 0

Silicct brick per cent
	45 0
	45 5


Frank Orth has designed a checker in which the size of the
pass increases in four steps, being widest at the top and narrowest
at the bottom. While G. L. Danforth, Jr., arranges the top of the
checkerwork in a series of blocks surrounded by channels about
6 in wide and about 2 ft deep. Another arrangement, by Dan-
forth, provides a number of pits in the top of the checkerwork.
The number, perimeter and depth of the pits giving an entry area
eqxial to the entry area at the top of the checkerwork. In both
cases the purpose is to provide space for the deposit and at the
name time prevent it from blocking up the checkerwork. .The
dust deposit will in time attain a thickness of 1.0 to 2.0 in at
the top of the checker and its effect in increasing the resistance