CENTRIFUGAL PUMP FOR VISCOUS MEDIA

POMPE CENTRIFUGE POUR MATIERES VISQUEUSES

English Abstract

ABSTRACT
CENTRIFUGAL PUMP FOR VISCOUS MEDIA
The present invention is directed to a centrifugal
pump of the type including an essentially conical rotor
having a helical vane increasing in diameter from its
entrance end to its discharge end; the peripheral edge
of the vane confronting the wall of the pump housing
and forming with the pump housing a discharge or pressure
chamber and an intake or suction chamber, the peripheral
edge of the vane diverging from the wall of the pump
housing from the discharge chamber toward the intake
chamber, and having minimal clearance with respect to
the wall of the discharge side of the vane.

Claims

The embodiments of the invention in which an
exclusive property or privilege is claimed are defined
as follows:
1. A centrifugal pump for a viscous conveyance
medium containing solid particles comprising:
a. a housing defining a pump chamber having
an internal wall defining an intake end and a discharge end;
b. a rotor journalled in the pump chamber
and including at least one helical vane having a peripheral
surface in confronting relation to the wall of the pump
chamber dividing the pump chamber and, at the opposite
side of the vane, a discharge pressure chamber;
c. the major portion of the peripheral surface
of the vane diverging from the wall of the housing toward
the intake chamber; and
d. the remaining minor portion of the peripheral
surface of the vane adjacent the side thereof exposed to the
discharge pressure chamber, being in close proximity to the
wall of the housing, and the area of said minor portion being
such as to minimize the quantity of solid particles capable
of being received between said minor portion and the con-
fronting wall, the solid particles on passing said minor
portion being transported away from the vane by the convey-
ance medium entering between said major portion and con-
fronting wall.
2. A centrifugal pump as defined in Claim 1,
wherein:
a. the diverging major surface occupies essen-
tially the entire width of the vane, reducing the minor
portion essentially to a peripheral line.
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3. A centrifugal pump as defined in Claim 1,
whereas:
a. the diverging angle between the major
portion of the peripheral surface of the vane and the
confronting wall is between 15° and 40°.
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Description

719
Centrifugal pumps Eor viscous fluid, particularly those
containing solids, have be~n used which include sn essentially conlcal
rotor having a helical vane increasing diameter from its entrance end to
its discharge end, the vane confronting a wall of the pump housing to
form with the pump housing an intake or suction chamber, and a discharge
or pressure chamber. The peripheral surface of the vane is fitted as close
to the pump housing as possible to minimize backflow between the discharge
chamber and the intake chamber.
Shearing forces develop in the gap between the peripheral
surface of the vane and the pump housing wall, such shearing forces
increase with viscosity and also with decrease in the diminsions of the
gap and increase in the area of the peripheral surface of the vane. If the
viscous material is contaminated with solid particles, such particles
tend to accumulate between the peripheral surface of the vane and the
confronting wall surface to the extent that rotation may be blocked.
The primary object of the present invention is to overcome the
problem inherent with centrifugal pumps of the type noted; more particularly,
the surface of the vane confronting the wall of the pump housing is so
arranged as to diverge from the wall in a direction away from the discharge
chamber and toward the intake chamber so that only a thin margin of the
peripheral vane surface remains in close proximity to the wall. As a
result, solid particles cannot collect between the vane surface and wall,
but instead, are forced from the discharge chamber back into the intake
chamber.
According to the invention a centrifugal pump for a viscous
conveyance medium containing solid particles comprises: a. a housing
defining a pump chamber having an internal wall defining an intake end and
a discharge end; b. a rotor journalled in the pump chamber and including
at least one helical vane having a peripheral surface in confronting
3~ relation to the wall of the pump chamber dividing the pump chamber and,
at the opposite side of the vane, a discharge pressure chamber; c. the
m~jor portion of the peripheral surface of the vane diverging from the wall
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71~
of the housing toward the intake chamber; and d. the remaining mlnor
portion of the peripheral aurface of the vane adJacent the side thereof
exposed to the discharge pressure cnamber, being ln close proximity to the
wall of the housing, and the area ot said minor portion being such as to
minimize the quantity of solid particles capable of being received between
said minor portion and the confronting wall, the solid particles on passing
said minor portion being transported away from the vane by the conveyance
medium entering between said major portion and confronting wall.
Figure 1 is a side view of the centrifugal pump
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7 ~13
with the pump housing in section and the rotor in elevation.
Figure 2 is an enlarged fragmentary sectional view
of the rotor showing particularly the rotor vane and the
conronting portion of the pump housing wall.
The pump includes a pump housing 1 having an
axially directed inlet 2 forming a pump chamber having
diverging walls 3 and a tangental outlet 4.
Fitted within the pump housing is a rotor 5 having
one or more vanes 6. The rotor is mounted on a shaft
suitably supported by a bearing enclosed in a bearing
housing 7.
The construction so far described may be considered
as conventional.
The vane 6 divides the pump housing into a discharye
or pressure chamber 8 downstream of the vane and an intake
or suction chamber 9 upstream of the vane. The thickness 10
of the vane determines a peripheral surface confronting the
wall 6 of the housing which includes a major portion 11
diverging toward the intake chamber 9 and a narrow marginal
portion 12 spaced from the pump housing wall a minimal
distance 13. The diverging portion 11 forms with the pump
housing wall an angle within the range between 15 and 40.
While the marginal portion 12 is shown as parallel to the
wall surface, the width may be reduced to line; that is,
essentially the entire width of the radially outer edge
surface of the vane may be tapered.
Operation of the centrifugal pump is as follows:
The marginal portion 12 being narrow minimizes
the quantity of solid particles capable of being received
between the marginal portion 12 and the confronting wall,
and, hence, minimizes the breaking effect produced by the

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particles ?resented to the marginal portion 12. Because
of the narrow dimension of the marginal portion 12, the
effective time a particle is presented thereto is minimized.
That is, the particles quickly pass the marginal portion 12
and are carried away by the conveyance media enteriny between
the diversing surfaces of the marginal portion 12 and housing
wall.
Having fully described my invention, it is to be
understood that I am not to be limited to the details herein
set forth, but that my invention is of the full scope of
the appended claims.