pa1778data.pdf

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U.S. STEEL DUQUESNE WORKS
HAER No. PA-115
(Page 151)
supported by notably less reinforcement than the hoist bucket.
Additionally, a new skip pit was constructed in the stockhouse to
accommodate the skip cars, new equipment was installed at the
furnace top in order to facilitate charging, and an extension to
the hoist house was built for the addition of two hydraulic
cylinders which operated the newly installed bells at the top of
the furnace.
The McKee process was adapted to the existing stockhouse
system of bins and scale cars which filled alternating skip cars
with raw materials while they were in the number 4 skip pit.
After filling, the skip cars were hoisted by a new dual drive 200
hp motor/drive/winch drum assembly, manufactured by the Superior
- Lidgerwood - Mundy Company and located in the hoist house, to
the top of the furnace where the raw materials were deposited
into a receiving hopper which delivered them, by gravity, to the
hopper containing the revolving distributor. The bell shaped
distributor sat directly on top of the small bell. Upon its
rotation, compressed air was introduced into the small bell's
hydraulic cylinder thereby beginning the reaction which
simultaneously raised the cylinder and lowered the lever arm
connected to the small bell at the top of the furnace. As the
small bell was lowered the desegregated material dropped onto the
large bell. The small bell was raised back up to its gas seal
position by withdrawing the compressed air from its cylinder,
after which the process was repeated with respect to the large
bell's raising and lowering apparatus in order to drop the
materials into the furnace proper. As one skip car was dropping
its contents into the charging equipment at the furnace top the
other was being filled with materials in the skip pit.
The adaptation of the raw materials delivery system to the
McKee arrangement at blast furnace number 3 involved only the
replacement of the 250 cu. ft. hoist bucket with one 267 cu. ft.
skip car. Additional increases of the capacity of blast furnace
number 3 were impractical because of the character of its
production. During this time the furnace only produced ferro-
manganese, a product which melted at such high temperatures that
a constant vigilance was required in order to prevent it from
burning through the furnace lining and shell. 9
The construction of Dorothy 6 between i960 - 1962 was
undertaken to replace dismantled blast furnaces numbers 5 and 6.
Designed and built by John Mohr and Sons of Chicago, Illinois,
the furnace produced more than twice the iron generated by the
dismantled furnaces together. It did so because of its large
hearth diameter (28'-0"), its large working volume (58,340 cu.
ft.) and because of the installation of the most modern raw
materials delivery system for its time. Novel features of the