35 / 84
kiln. The spring plates were cut across the middle,
leaving one half attached to the gear and the other
attached to the kiln shell. The super bolts could
then be removed, with care given to the jackbolt
loosening procedure. This left the gear half resting
freely on top of the kiln. Finally, the upper gear half
was lifted from the kiln shell and lowered to ground
level by crane and placed on prepared cribbing.
With the first gear half on the ground, spring
plate removal could begin. The spring plate pins
were held in place by washers welded to each of
their ends. The washers, pins, and, finally the spring
plates were carefully cut, as needed, and removed
without damaging the gear. The spring plate and pin
removal was difficult and the gear frame could easily
have been damaged with a less experienced crew.
Once each of the pins and spring plates were
removed, the diameter of the pinholes in the gear
could be measured and recorded. At the same time,
the diameters of the new pins and holes in the new
spring plates were measured and recorded. This was
done in order to facilitate the matching of each pin
to its most appropriately sized hole. The new pins,
washers, and spring plates were then installed in
their correct locations and the washers were welded
in place. The spring plates were then bound in place
to prevent problematic movement during lifting.
In addition to the new spring plates, alignment
‘chairs’ were mounted on the gear half using their
pre-installed adjustment bolts. These would be used
as temporary attachment points between the gear
and the kiln shell, as well as adjustment fixtures
during the alignment.
During the gear half’s time on the ground, the
remainder of each spring plate, still attached to the
kiln shell, was removed by air arcing and grinding.
With the new spring plates and chairs in place, the
gear half was lifted and placed on top of the kiln, this
time in its new reversed orientation. All eight super
bolts were reinstalled using the appropriate torque
specifications and procedure. Then, the ‘chairs’ were
welded to the kiln shell. In order to assist the chairs
in driving the kiln during rotation, drive bars were
installed on each of the new spring plates. This
consisted of a bar welded laterally to the spring plate
with a fixture on each end attached to the bar with
adjustable bolts. Adding these attachment points
between the gear and shell reduced the load on
the chairs and also held the otherwise free hanging
spring plates in position.
Once the gear half was in place with chairs,
and the drive bars and super bolts installed, the
kiln could be rotated to position the second gear
half on top of the kiln shell. The same process was
then executed with the other half, to remove
and reinstall it with the new spring plates, in the
reversed orientation. This time, newly supplied super
bolts were installed to join the gear halves.