pa1778data.pdf
pa1778data.pdf
pa1778data.pdf
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#<br />
U.S. STEEL DUQUESNE WORKS<br />
HAER No. PA-115<br />
(Page 97)<br />
each regulated by a value, introduced the air into each stove.<br />
The 21'-0" diameter x 96*-0" high domed Cowper-Kennedy hot<br />
blast stoves were constructed of a steel plate shell which<br />
enclosed a central combustion chamber surrounded by brick<br />
checkerwork consisting of 9" square holes with rounded corners<br />
between the courses of firebrick. In order to pre-heat the cold<br />
blast, the brick inside of the stoves was heated by means of<br />
burning the waste gas flowing from the top of the blast furnace.<br />
The gas, which left the furnace top at average temperatures of<br />
500 degrees F., was first cleaned of large entrained particulate<br />
by taking it from the top of the furnace through a 10*-0"<br />
diameter refractory brick lined pipe called a downcomer into the<br />
28*-0" diameter dust catcher. Upon entering the larger diameter<br />
dust catcher the velocity at which the gas was traveling slowed,<br />
thereby allowing the larger particulate to drop to the bottom of<br />
it as the gas rose out of its top through a 10*-0" diameter gas<br />
main leading to the burner connection on the hot blast stoves.<br />
The gas was then burned up through the combustion chamber with<br />
the aid of combustion air drawn into the burner by an<br />
electrically motor powered fan located at each stove. In the<br />
process, it was deflected by the dome downwards through the holes<br />
in the checkerwork surrounding the combustion chamber. When the<br />
checkerwork had become sufficiently hot, the cold blast air was<br />
admitted into the stove. It also rose up through the combustion<br />
chamber to the dome which deflected it downwards through the<br />
holes in the checkerwork before it passed out of the stove's<br />
valve regulated hot blast connection into the hot blast main.<br />
The hot blast main led directly to a bustle pipe surrounding the<br />
blast furnace where separate branches, composed of an elbow<br />
connected to a blow pipe, delivered the air into the furnace<br />
tuyeres. The temperature of the hot blast was governed by means<br />
of a mixing system consisting of a valve regulated 18" pipeline<br />
running from the cold blast to the hot blast main. By<br />
introducing varied amounts of cold air into the hot blast main a<br />
constant temperature of approximately 1000 degrees F. was<br />
maintained. This procedure was necessary because a stove<br />
normally heated the cold blast to temperatures higher than 1000<br />
degrees at the beginning of its air cycle before gradually giving<br />
up its heat. When the stove could no longer heat the blast to<br />
1000 degrees it was put back on gas. Under normal conditions,<br />
the operation of the stoves was alternated with three stoves on<br />
gas while the other was on air. 1<br />
Difficulties encountered with the performance of the hot<br />
blast stoves, and the installation of gas fired blowing engines<br />
associated with the addition of blast furnaces numbers five and<br />
six in 1907 prompted Duquesne Works officials to experiment with<br />
new methods of cleaning blast furnace gas. The problem centered