Appeal 2007-1722
Application 10/212,919
(annular lip 50) is shown received within a corresponding cutout or recess 24 of
the labyrinth, as required by the claims.
Appellants further argue that claims 23 and 25 require that the projection 2
have an inner edge that extends downwards from a rounded tip, or end, of the
annular lip to a suction liner face (or a follower plate surface) at an angle that
facilitates the deflection of particulate matter (Br. 3). The reason given for this
feature is that the angle of about 45 degrees minimizes the wear effect of particles
being thrown off the impeller. (Specification 7:1-3)
We do not consider the 45 degree angled surface on Appellants’ diverter to
patentably distinguish Appellants’ claims over Studebaker. As found supra
(FF 11), the sloping surface 56 on the follower plate/liner 34 shown in Figures 2
and 4 in Studebaker is an oblique surface inclined by definition to the rotational
axis at about 45°. The purpose of this sloping surface 56 is disclosed to reduce
wear by deflecting the slurry from the pressure relief vanes into the volute section
of the pump so as to protect the mating portions of the casing from abrasive slurry
action (FF 11). Similarly, the Specification describes that the 45° angled surface
on Appellants’ diverter minimizes the wear effect of the particles being thrown off
by the impeller (FF 10). Thus, a person with ordinary skill in the art would
understand that the result of using the 45° angled surface on the diverter (annular
lip 50) would yield a predictable result, e.g., deflecting particulates away from a
boundary surface and into the main flow, while reducing wear, such as taught by
the annular cap 54 of Studebaker. KSR, 127 S. Ct. at 1740, 82 USPQ2d at 1395.
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