pa1778data.pdf

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U.S. STEEL DUQUESNE WORKS
HAER No. PA-115
(Page 97)
each regulated by a value, introduced the air into each stove.
The 21'-0" diameter x 96*-0" high domed Cowper-Kennedy hot
blast stoves were constructed of a steel plate shell which
enclosed a central combustion chamber surrounded by brick
checkerwork consisting of 9" square holes with rounded corners
between the courses of firebrick. In order to pre-heat the cold
blast, the brick inside of the stoves was heated by means of
burning the waste gas flowing from the top of the blast furnace.
The gas, which left the furnace top at average temperatures of
500 degrees F., was first cleaned of large entrained particulate
by taking it from the top of the furnace through a 10*-0"
diameter refractory brick lined pipe called a downcomer into the
28*-0" diameter dust catcher. Upon entering the larger diameter
dust catcher the velocity at which the gas was traveling slowed,
thereby allowing the larger particulate to drop to the bottom of
it as the gas rose out of its top through a 10*-0" diameter gas
main leading to the burner connection on the hot blast stoves.
The gas was then burned up through the combustion chamber with
the aid of combustion air drawn into the burner by an
electrically motor powered fan located at each stove. In the
process, it was deflected by the dome downwards through the holes
in the checkerwork surrounding the combustion chamber. When the
checkerwork had become sufficiently hot, the cold blast air was
admitted into the stove. It also rose up through the combustion
chamber to the dome which deflected it downwards through the
holes in the checkerwork before it passed out of the stove's
valve regulated hot blast connection into the hot blast main.
The hot blast main led directly to a bustle pipe surrounding the
blast furnace where separate branches, composed of an elbow
connected to a blow pipe, delivered the air into the furnace
tuyeres. The temperature of the hot blast was governed by means
of a mixing system consisting of a valve regulated 18" pipeline
running from the cold blast to the hot blast main. By
introducing varied amounts of cold air into the hot blast main a
constant temperature of approximately 1000 degrees F. was
maintained. This procedure was necessary because a stove
normally heated the cold blast to temperatures higher than 1000
degrees at the beginning of its air cycle before gradually giving
up its heat. When the stove could no longer heat the blast to
1000 degrees it was put back on gas. Under normal conditions,
the operation of the stoves was alternated with three stoves on
gas while the other was on air. 1
Difficulties encountered with the performance of the hot
blast stoves, and the installation of gas fired blowing engines
associated with the addition of blast furnaces numbers five and
six in 1907 prompted Duquesne Works officials to experiment with
new methods of cleaning blast furnace gas. The problem centered