pa1778data.pdf

U.S. STEEL DUQUESNE WORKS
HAER No. PA-115
(Page 148)
The Neeland charging system utilized a system of bins which
were installed in a stockhouse constructed below the ground. The
bins, located along the east and west wall of the stockhouse and
composed of two counterbalanced chutes extending on each side of
the ore yard wall, released their raw materials into one of three
75 cu. ft. capacity hoist buckets which were equipped with a
movable bell shaped bottom, and were located on a rail car
outfitted with a weighing scale. After the proper amount had
been charged into the hoist bucket, the car was pushed by a small
locomotive to the base of the inclined hoist track located
approximately 50'-0" west of the centerline of the furnace. A
bifurcated hook hanging from the front axle of the hoist carriage
picked off the bucket handle extending from its stem and the
bucket was hoisted to the top of the furnace by means of a 14" x
16", 300 hp Crane vertical reversing steam engine located in one
of the original hoist houses. When the bucket neared the top of
the furnace, gauges located on a panel board in the hoist house
alerted the hoisting engineer to slow down the speed of delivery
by adjusting governing valves attached to the steam engine while
the carriage was lowered into a sliding frame, allowing the lower
flange of the bucket to rest upon the gas seal hopper of the
furnace. As the sliding frame continued to lower, the bell
shaped bottom of the bucket moved away from its casing and pushed
a gas sealing bell down with it, allowing the raw materials to
drop down evenly over the main bell of the furnace. The main
bell was then lowered by means of a compressed air cylinder,
controlled and operated inside of the hoist house by the hoisting
engineer, releasing the raw materials into the furnace.
The Neeland raw materials delivery system made it possible
to use the potentially more productive fine iron ores of the
Mesabi Range. Fine ores, if not distributed evenly inside of the
furnace alongside coarser ores, often stuck to the inside wall
often clogging the furnace, resulting in the creation of a void
between stock levels. As a result, explosions or "slips"
occurred inside the furnace as the bridged stock eventually fell
downwards filling the void. Production and human safety suffered
because the "slip" caused raw materials to spew out of the
furnace top. Until the application of the Neeland design, the
only way to insure even distribution of these ores was by the use
of the slower hand filling methods. Neeland counteracted the
problem of "slips" by designing the system so that the centerline
of the movable bucket bell coincided with the centerline of the
large bell and furnace itself when the materials were discharged
from the bucket, thus insuring a more even distribution. 3
Many of the physical features of the raw materials handling
system for blast furnaces numbers l through 6 were reconstructed
between 1918 and 1924 as part of an effort to keep pace with