Appeal No. 97-1078
Application 08/448,056
combustion air flowing into the tank. Each of the
regenerators includes a network or checker setting 13 of
refractory brick. The checker settings have three wear zones:
the top checkers 13T, the middle checkers 13M and the bottom
checkers 13B. According to Davies, “[t]he dominant service
factors in the top checkers are different than the middle and
lower zones. But, generally, the same factors are present to
some degree in all zones” (column 2, lines 15 through 19). In
this regard, Davies observes that
[f]our fundamental destructive effects have been
recognized as having a direct bearing on
checkerbrick life: (1) temperature cycling; (2)
oxidation-reduction; (3) solid carryover; and (4)
volatile carryover. In the top checker settings,
high-temperature cycling is a serious factor,
decreasing towards the middle where it overlaps with
low-temperature cycling effects. The atmosphere in
the top zone is laden with alkali vapors, although
condensation is insignificant. Solid carryover is
greatest. Oxidation-reduction conditions may vary
from mild to severe.
In the middle zone, temperature fluctuations are
relatively mild. Solid carryover is low and,
because of lower temperatures, less reactive. The
atmosphere is rich in alkali vapors, and some
deposition of condensates occurs. Oxidation-
reduction conditions may be present, but the effects
are of less importance because of lower
temperatures.
In the lower zone, temperatures are quite low,
but the temperature cycles may be wide where cold
incoming air enters the checker setting. The
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Last modified: November 3, 2007