pa1778data.pdf

U.S. STEEL DUQUESNE WORKS
HAER No. PA-115
(Page 150)
into the furnace, a turntable was installed on the floor in the
middle of the hoist bucket pit. The bucket, resting on the
turntable, was rotated after filling so as to insure the even
distribution of large and small pieces of material. 7
After rotation, the bucket was hoisted up an inclined track
resting on a reinforced bridge to the furnace top by means of
electrified equipment placed in a relocated hoist house at each
blast furnace. The hoist house was moved upwards, closer to the
center of gravity of the hoisting system, from the ground to the
top of a steel framed platform at an elevation of 4O'-0". In
addition, a counterweight hoist tower extending upwards from the
stockhouse floor was constructed just south of each hoist house.
By using this design, plant engineers were able to significantly
lessen the workload of the hoisting machinery. The electrified
hoisting machinery converted alternating electrical current drawn
from plant power stations by means of a direct current motor-
generator set before transferring the converted current to a
motor/drive/winch drum assembly which hoisted the bucket up the
incline. Regulating the speed of hoist travel was made easier by
the use of direct current and by the attachment of automatic
governing equipment to each motor/drive/winch drum assembly.
Finally, steam operated equipment for regulating the large bell
was installed in the stockhouse and on top of each furnace. 8
Between 1924 and 1953 adjustments to the individual blast
furnace raw materials delivery systems were relatively minor. In
the 1930s, for example, vibrating coke screens operated by 2 hp
motors (manufactured by The W. S. Tyler Company), replaced the
stationary screens in the coke breeze separation process and a
small motor/drive/winch drum assembly was installed in each hoist
house for the stockline recorder. The period between 1953 and
1962, however, witnessed a second major reconstruction and
upgrading of the system. It consisted of replacing the Neeland
system at blast furnaces numbers 3 and 4 with a system designed
by the Arthur G. McKee Company of Cleveland, Ohio, dismantling
blast furnaces numbers 5 and 6, the construction of a new blast
furnace number 6 (Dorothy 6), and the alteration of the coke
breeze removal process.
The Neeland arrangement was replaced at the time of the
scheduled relining of blast furnaces 3 and 4 in 1953 and 1959
respectively, because the McKee system allowed furnace men to
significantly increase iron production by increasing the capacity
of raw materials charged into the furnace over each twenty-four
hour period. This was especially evident at blast furnace number
4 where the inclined bridge of the Neeland design was replaced by
a bridge designed to support two 267 cu. ft. capacity skip cars.
The new bridge was made possible because skip cars could be