Appeal No. 97-1078
Application 08/448,056
dominant characteristic of this zone is a large
amount of condensing volatile constituents from the
exhaust gases. Effects of oxidation-reduction and
solid carryover on the refractories in this area are
insignificant, although plugging may occur from the
entrapment of solid dust fragments from higher up in
the setting [column 2, lines 41 through 66].
Davies’ objective is to provide a regenerator structure
which will have “a longer and more uniform service life”
(column 1, lines 59 and 60). To this end, the reference
teaches that
[t]he lower sections of the checker setting are
comprised of chrome or chrome-magnesite brick.
Middle settings are selected from stabilized
forsterite, magnesite, or chrome-magnesite brick.
The upper checker settings, which are the most
critical, are comprised of burned or unburned high-
purity magnesite brick, on an oxide basis, by
weight, analyzing at least 90% MgO up to about 2%
total Al O plus Fe O plus Cr O there being lime and23 2 3 2 3
silica present, the lime/silica weight ratio being
greater than 2:1. In a preferred embodiment the top
checker settings are comprised of magnesite brick
containing by weight on an oxide analysis of at
least 95%, of MgO up to about 1%, by weight total
Al O plus Fe O plus Cr O , there being lime and23 2 3 2 3
silica present, the lime/silica weight ratio being
about 2:1 [column 2, lines 25 through 40].
The examiner concedes (see page 4 in the main answer)
that Davies does not meet the limitation in independent claim
12 requiring the second honeycomb body to comprise a ceramic
material having a main crystal phase of cordierite.
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Last modified: November 3, 2007