Goulds Pumps 3500XD - IOM - Manual (Page 14)

INTRODUCTION
The Goulds Model 3500XD heavy duty stock pump is a
centrifugal pump designed to handle paper stock up to
approximately 16% O.D. consistency. The pump design incorporates special features to induce flow into the pump
suction and to remove air that is present in stock at higher
consistencies.
DESIGN CONCEPT
There are two major obstacles in pumping paper stock at
consistencies above 8% with a centrifugal pump: the
formation of a fiber network that will not readily flow, and
high air content which can cause air binding of a standard
centrifugal pump.
The Model 3500XD pump is normally attached to a suction
vessel or “standpipe,” and a constant level is maintained
above the suction centerline. An X-Ducer mounted on the
end of the pump shaft creates turbulence in the suction
standpipe (Fig. 4, Zone 1), breaking up the fiber network
and separating air from the pulp. The pulp is then induced
to flow into the pump suction by the static head in the
standpipe and the pumping action of the X-Ducer. The
amount of turbulence required (minimum pump speed) as
well as the minimum standpipe level is a function of the
stock type, quality, consistency and temperature of each
specific application.
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3500XD IOM 8/07
Fig. 4