U.S. patent application number 14/667352 was filed with the patent office on 2016-09-29 for centrifugal pump intake pipe with a helical flow path.
The applicant listed for this patent is SYNCRUDE CANADA LTD. in trust for the owners of the Syncrude Project as such owners exist now and. Invention is credited to STEPHEN HARASYM, KEVIN REID.
Application Number | 20160281733 14/667352 |
Document ID | / |
Family ID | 56975043 |
Filed Date | 2016-09-29 |
United States Patent
Application |
20160281733 |
Kind Code |
A1 |
REID; KEVIN ; et
al. |
September 29, 2016 |
CENTRIFUGAL PUMP INTAKE PIPE WITH A HELICAL FLOW PATH
Abstract
An intake pipe for directing a slurry towards an impeller of a
centrifugal pump defines a helical flow path oriented to swirl the
slurry in a rotational direction of the impeller.
Inventors: |
REID; KEVIN; (Edmonton,
CA) ; HARASYM; STEPHEN; (Edmonton, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SYNCRUDE CANADA LTD. in trust for the owners of the Syncrude
Project as such owners exist now and |
Fort McMurray |
|
CA |
|
|
Family ID: |
56975043 |
Appl. No.: |
14/667352 |
Filed: |
March 24, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F05D 2250/51 20130101;
F05D 2250/25 20130101; F04D 29/4293 20130101; F04D 7/04
20130101 |
International
Class: |
F04D 29/42 20060101
F04D029/42; F04D 29/22 20060101 F04D029/22; F04D 13/12 20060101
F04D013/12; F04D 1/00 20060101 F04D001/00; F04D 7/04 20060101
F04D007/04 |
Claims
1. An intake pipe for directing a slurry towards an impeller of a
centrifugal pump, wherein the intake pipe defines a helical flow
path oriented to swirl the slurry in a rotational direction of the
impeller.
2. The intake pipe as claimed in claim 1, wherein the intake pipe
comprises a helical portion having a diameter and a length, a pitch
over diameter of about 2, and an eccentricity radius over diameter
of about 0.2.
3. The intake pipe as claimed in claim 1, wherein the intake pipe
comprises a helical portion having a length of about 15,000 mm, a
pitch of about 1,500 mm, and an eccentricity radius of about 150
mm.
4. The intake pipe as claimed in claim 1, wherein the intake pipe
comprises a helical portion having a length of 15,000 mm, a pitch
of 1,500 mm, and an eccentricity radius of 150 mm.
5. A pump assembly for a slurry, the assembly comprising: (a) a
volute defining an axial pump inlet, a radial pump outlet, and a
pump chamber for an impeller rotatable about an axial impeller
axis; and (b) an intake pipe in fluid communication with the pump
inlet and defining a helical flow path oriented to swirl the slurry
in a rotational direction of the impeller.
6. The pump assembly as claimed in claim 5, wherein the intake pipe
comprises a helical portion having a diameter and a length, a pitch
over diameter of about 2, and an eccentricity radius over diameter
of about 0.2.
7. The pump assembly as claimed in claim 5, wherein the intake pipe
comprises a helical portion having a length of 15,000 mm, a pitch
of 1,500 mm, and an eccentricity radius of 150 mm.
8. A pump system comprising: (a) a first pump; (b) a second pump,
wherein the second pump is a centrifugal pump comprising an
impeller; and (c) an intake pipe for directing a slurry from the
first pump to the impeller of the second pump, wherein the intake
pipe defines a helical flow path oriented to swirl the slurry in a
rotational direction of the impeller.
9. The pump assembly as claimed in claim 8, wherein the intake pipe
comprises a helical portion having a diameter and a length, a pitch
over diameter of about 2, and an eccentricity radius over diameter
of about 0.2.
10. The pump system as claimed in claim 8, wherein the intake pipe
comprises a helical portion having a length of 15,000 mm, a pitch
of 1,500 mm, and an eccentricity radius of 150 mm.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to pumping of slurries, and
more particularly to intake pipes for centrifugal pumps used to
pump slurries.
BACKGROUND OF THE INVENTION
[0002] Oil sands ores mined in Alberta, Canada are crushed and
mixed with heated water, steam and caustic (NaOH) to produce
slurries to be processed to recover bitumen. Centrifugal pumps are
used to hydrotransport these oil sand slurries through pipe lines.
Centrifugal pumps are also used to transport oil sands tailings
through pipe lines.
[0003] Unlike single phase liquids, these slurries may contain
hard, solid lumps that measure up to several inches in diameter.
These lumps impact the impeller vanes of the centrifugal pumps with
high relative velocity and thereby wear or damage the impeller
vanes. The repair or replacement of the impeller vanes and the
associated loss of productivity is a significant expense.
[0004] Accordingly, there is a need in the art for devices that may
be used to mitigate wear or damage to impeller vanes of centrifugal
pumps caused by dense slurries and larger solid particles in
slurries.
SUMMARY OF THE INVENTION
[0005] In one aspect, the present invention comprises an intake
pipe for directing a slurry towards an impeller of a centrifugal
pump, wherein the intake pipe defines a helical flow path oriented
to swirl the slurry in a rotational direction of the impeller.
[0006] In another aspect, the present invention comprises a pump
assembly for a slurry, the assembly comprising a volute, and an
intake pipe. The volute defines an axial pump inlet, a radial pump
outlet, and a pump chamber for an impeller rotatable about an axial
impeller axis. The intake pipe is in fluid communication with the
pump inlet and defines a helical flow path oriented to swirl the
slurry in a rotational direction of the impeller. The pump inlet
may be positioned to reduce the amount of the volute that solid
particles in the slurry flow through before being discharged at the
radial pump outlet.
[0007] In another aspect, the present invention comprises a pump
system comprising a first pump, a second pump, and an intake pipe
that directs a slurry from the first pump to the impeller of the
second pump, wherein the intake pipe defines a helical flow path
oriented to swirl the slurry in a rotational direction of the
impeller.
[0008] In one embodiment, the intake pipe comprises a helical
portion having a diameter and length, a pitch over diameter of
about 2, and an eccentricity radius over diameter of about 0.2. In
one embodiment, the helical portion has a diameter of about 700 mm
(28''), a length of about 15,000 mm, a pitch of about 1,500 mm and
an eccentricity radius of about 150 mm.
[0009] With the use of a computational fluid dynamics model, it was
demonstrated that the intake pipe of the present invention,
relative to a straight intake pipe, may result in reduced wear of
the impeller and the volute of a centrifugal pump attributable to
impacts between these pump components and the larger solid
particles (lumps) in the slurry.
[0010] Without restriction to a theory, it is believed that this
effect is due to the intake pipe imparting a circumferential
velocity to the solid particles in the slurry, which may reduce the
impact velocity of the solid particles with these pump components,
and the amount of impacts between the solid particles and these
pump components, and also to the intake pipe reducing the axial
velocity of the solid particles prior to flowing into the
centrifugal pump.
[0011] Other features will become apparent from the following
detailed description. It should be understood, however, that the
detailed description and the specific embodiments, while indicating
preferred embodiments of the invention, are given by way of
illustration only, since various changes and modifications within
the spirit and scope of the invention will become apparent to those
skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Referring to the drawings wherein like reference numerals
indicate similar parts throughout the several views, several
aspects of the present invention are illustrated by way of example,
and not by way of limitation, in detail in the following figures.
It is understood that the drawings provided herein are for
illustration purposes only and are not necessarily drawn to
scale.
[0013] FIG. 1 is a perspective view of one embodiment of the intake
pipe of the present invention.
[0014] FIG. 2 is a schematic depiction of the geometry of one
embodiment of the intake pipe of the present invention.
[0015] FIG. 3 is a perspective view of one embodiment of the intake
pipe of the present in invention, connected to one embodiment of a
centrifugal pump.
[0016] FIG. 4 is a vector diagram illustrating the predicted effect
of one embodiment of the intake pipe of the present invention on
the impact velocity of a solid particle in the slurry with an
impeller vane of a centrifugal pump.
[0017] FIG. 5 shows the flow path of a plurality of solid particles
in a slurry flowing through one embodiment of an intake pipe of the
present invention, and in the volute of a centrifugal pump, as
predicted by a computational fluid dynamics model.
[0018] FIG. 6 is a graph comparing the swirl velocity of a single
phase fluid flowing through one embodiment of an intake pipe of the
present invention, as predicted by a computational fluid dynamics
model to experimental results.
[0019] FIG. 7 is a graph comparing the pressure gradient of a
single phase fluid flowing through one embodiment of an intake pipe
of the present invention, as predicted by a computational fluid
dynamics model, to experimental results.
[0020] FIG. 8 is a graph comparing the average circumferential
velocity of solid particles of a slurry flowing through embodiments
of the intake pipe of the present invention having different
combinations of pitches and eccentric radii, as predicted by a
computational fluid dynamics model.
[0021] FIG. 9 is a graph comparing the average circumferential
velocity of a single phase fluid of a slurry flowing through
embodiments of the intake pipe of the present invention having
different combinations of pitches and eccentric radii, as predicted
by a computational fluid dynamics model.
[0022] FIG. 10 is a graph comparing the average head loss (above
that of an equivalent straight pipe) of a single phase fluid of a
slurry flowing through embodiments of the intake pipe of the
present invention having different combinations of pitches and
eccentric radii, as predicted by a computational fluid dynamics
model.
[0023] FIG. 11 is a graph showing the average axial velocity of
solid particles in a slurry flowing through one embodiment of an
intake pipe of the present invention, as predicted by a
computational fluid dynamics model.
[0024] FIG. 12 shows one embodiment of the position of one
embodiment of the intake pipe of the present invention relative to
the impeller of a centrifugal pump, intended to increase the amount
of the volute that the solid particles of the slurry pass through
before being discharged from the volute.
[0025] FIG. 13 shows an alternative embodiment of the position of
one embodiment of the intake pipe of the present invention relative
to the impeller of a centrifugal pump, intended to reduce the
amount of the volute that the solid particles of the slurry pass
through before being discharged from the volute.
[0026] FIGS. 14A and 14B show the erosion of the volute of a
centrifugal pump caused by solid particles of a slurry flowing
through a straight pipe and one embodiment of an intake pipe of the
present invention, respectively, as predicted by a computational
fluid dynamics model.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0027] The detailed description set forth below in connection with
the appended drawings is intended as a description of various
embodiments of the present invention and is not intended to
represent the only embodiments contemplated by the inventor. The
detailed description includes specific details for the purpose of
providing a comprehensive understanding of the present invention.
However, it will be apparent to those skilled in the art that the
present invention may be practiced without these specific
details.
[0028] The present invention relates generally to an intake pipe
for a centrifugal pump. When describing the present invention, all
terms not defined herein have their common art-recognized meanings.
To the extent that the following description is of a specific
embodiment or a particular use of the invention, it is intended to
be illustrative only, and not limiting of the claimed invention.
The following description is intended to cover all alternatives,
modifications and equivalents that are included in the spirit and
scope of the invention, as defined in the appended claims. As used
herein, the term "slurry" refers to a fluid mixed with solid
particles.
[0029] FIG. 1 shows one embodiment of an intake pipe 10 of the
present invention used to supply a slurry to a centrifugal pump. In
general, the intake pipe 10 comprises a pipe inlet 12, a pipe
outlet 14, and a helical portion 16. The pipe inlet 12 is for fluid
communication with a slurry source. The pipe outlet 14 is for fluid
communication with the pump inlet of a centrifugal pump. The
helical portion 16 of the intake pipe 10 defines a helical flow
path to swirl the slurry in the rotational direction of the
impeller of a centrifugal pump. The intake pipe 10 may be made of
any rigid material suitable for conveying the slurry to a
centrifugal pump, and may be formed using any suitable techniques
known in the art such as casting, molding, extrusion or a
combination of the forgoing.
[0030] FIG. 2 schematically illustrates the geometry of part of the
helical portion of one embodiment of the intake pipe 10. As used
herein, "longitudinal" refers to the general direction of slurry
flow within the helical portion 16 of the intake pipe 10, and
"transverse" refers to a direction perpendicular to the
longitudinal direction. In this embodiment, the helical portion 16
has a circular transverse cross-section C of constant diameter
along the length of the intake pipe 10. The geometric center of the
transverse cross-section C is offset from the longitudinal axis L,
and revolves around the longitudinal axis L in a substantially
circular path P, as the cross-section progresses along the length
of the helical portion 16, thus tracing a helical curve H. This
geometry of the helical portion 16 may be quantitatively described
by its length, pitch and eccentricity radius. The "length" refers
to the longitudinal dimension of the helical portion 16, which will
be made up of a number of pitches. The "pitch" refers to the
longitudinal distance in which the geometric center of the
transverse cross-section makes one revolution around the
longitudinal axis. The "eccentricity radius" refers to the
transverse distance between the geometric center of the transverse
cross-section C and the longitudinal axis L.
[0031] FIG. 3 shows one embodiment of the pump assembly 100 of the
present invention. In general, the pump assembly 100 comprises a
volute 20 of a centrifugal pump and an intake pipe 10.
[0032] The volute 20 provides a chamber in which the pressure and
velocity of the slurry is increased by an impeller 30 rotating
about an impeller axis. As used herein, the "axial" refers to the
direction defined by the impeller axis, and "radial" refers to a
direction perpendicular to the axial direction. The volute 20
defines a pump chamber 21 for the rotatable impeller 30 extending
between an axial pump inlet 22, and a radial pump outlet 24. In the
embodiment shown in FIG. 3, the pump outlet 24 discharges into a
short length of discharge pipe 26 with a diffuser 28.
[0033] The intake pipe 10 is as described above in reference to
FIG. 1. The pipe outlet 14 connected to the pump inlet 22 to convey
the slurry from the intake pipe 10 into the pump chamber 21. The
helical flow path of the intake pipe 10 is oriented to swirl the
slurry in the same direction as the rotational direction of the
impeller 30 as the slurry flows towards the pump inlet 22. In FIG.
3, for example, when viewed from the direction from the pipe inlet
12 towards the pipe outlet 14, the impeller 30 rotates in an
anticlockwise direction, and so the helical portion 16 also swirls
the slurry in an anticlockwise direction.
[0034] FIG. 4 shows a velocity vector diagram illustrating the
theoretical principle of the intake pipe 10 of the present
invention. The vector V.sub.it represents the tangential velocity
at the leading edge of the rotating impeller 30, at given moment in
time. The vector V.sub.pa represents the axial component of the
velocity of a solid particle in the slurry flowing towards the
impeller 30. The vector V.sub.pt represents the tangential
component of the velocity of the solid particle in the slurry,
imparted by the swirling effect of the helical portion 16 intake
pipe 10 on the slurry. The vector .DELTA.V represents the impact
velocity between the impeller and the solid particle of the slurry.
The length of the vectors in FIG. 4 represent their respective
magnitudes. As such, the impact velocity .DELTA.V of the solid
particle with the impeller 30 will approach a minimum value as the
tangential velocity of the solid particle approaches the tangential
velocity of the impeller 30.
Numerical Modelling of Pump System
[0035] A three-dimensional numerical computational fluid dynamics
model implemented with the ANSYS CFX.TM. computational fluid
dynamics software package was used to support the above theory and
predict parametric effects of different intake pipe 10 geometries.
The volute 20 and impeller 30 models were based on an commercially
available high-pressure pump, with a 57.5 inch diameter impeller,
28 inch discharge pipe section and a 24 inch.times.28 inch
diffuser, without any leakage flow paths. The liquid phase of the
slurry was modeled as a single continuous phase having a density of
1500 kg/m.sup.3 and a viscosity of 0.715 cP, which is
representative of an oil sands slurry comprising bitumen, sand,
clay and air. Turbulence effects in the liquid phase were modeled
using the k-.omega. SST turbulence model with scalable wall
functions. The solid particles of the slurry were modeled using
discrete spherical particles having a diameter of 5 inches,
accounting for drag and buoyancy forces, but ignoring blockage
effects. The effects of the particles on the flow field, and
inter-particle interactions were ignored.
Effect on Particle Flow Path
[0036] The model was used to predict the particle flow path in an
intake pipe 10 having a diameter of 28 inches, a helical portion 16
with a length of 9,000 mm, pitch of 1,500 mm and eccentricity
radius of 150 mm, with a slurry flow rate of 7,200 m3/hr. Of
course, it is understood that other geometries could be used
depending upon a number of factors such as pump type, pump size,
etc.
[0037] FIG. 5 graphically shows, for one embodiment of the pump
system 100, the flow path of a plurality of solid particles of the
slurry as the slurry flows through the helical portion of the
intake pipe (not shown), impacts the anticlockwise rotating
impeller 30 and circulates through part of the volute (not
shown).
[0038] As can be seen from FIG. 5, the flow paths of the solid
particles have a significant directional component that is
tangential to the circular path circumscribed by the vanes of the
rotating impeller. The model predicts that the solid particles are
mostly concentrated in a ribbon-like stream which follows the helix
of the undulating pipe. In reality, the particles may not follow
such a concentrated ribbon pattern due to their volume, but it
would reasonably be expected that a large number of the solid
particles would follow a predictable path governed by the geometry
of the helical portion of the intake pipe 10. This is because the
particles are expected to follow the outer surface of the inner
wall of the intake pipe 10 due to the centrifugal force acting on
the particles, and the fact that the density of the particles is
greater than the density of the slurry. If the length of straight
pipe between the undulating pipe and the pump inlet is kept
sufficiently short, it should be possible to control where a large
portion of the particles, in particular, the larger lumps within
the slurry, e.g., greater than 10 mm, will enter the pump inlet 22
and to control the tangential velocity of the larger lumps.
Effect of Eccentricity Radius and Pitch on Fluid and Solid Particle
Swirl Velocity, Fluid Pressure
[0039] The model was validated for an intake pipe 10 having a
helical portion with a pitch of 152 mm and an eccentricity radius
of 17 mm using experimental data for a single phase fluid in a pipe
of laboratory scale. FIG. 6 is a graph comparing the predicted and
experimental swirl velocity of single phase liquid at different
radial locations across the transverse cross-section of the pipe
for slurry flowing at 3 m/s. FIG. 7 is graph comparing the
predicted fluid pressure at different axial locations of the intake
pipe for fluids flowing at different velocities. These graphs show
that the model can adequately predict the swirl velocity and
average pressure of a single phase fluid flow through an intake
pipe at the laboratory scale, once the flow has fully developed in
the helical portion.
[0040] With the model so validated, it was used to predict the
single phase fluid pressure drop and swirl velocity generated by
commercial scale intake pipes 10 having a helical portion with six
turns, and different pitches and eccentric radii. FIG. 8, FIG. 9,
and FIG. 10 are graphs showing the predicted effect of these
parameters on the average circumferential velocity of the solid
particles, the average swirl velocity of the single phase fluid,
and the pressure of the fluid, respectively. These graphs show that
the model predicts that decreasing the pitch and increasing the
eccentricity radius tends to increase the circumferential velocity
of the solid particles and fluid phase, and the pressure drop of
the fluid phase. Of note, circumferential velocities of the
particles are greater than the average circumferential fluid
velocity because the majority of the particles travel near the
outside wall of the inner surface of the intake pipe 10.
Effect of Length on Solid Particle Axial Velocity
[0041] The model was also used to predict the effect of the helical
portion 16 of the intake pipe 10 on the axial velocity of the solid
particles for an intake pipe 10 with a helical portion having a
length of 15,000 mm, a pitch of 1,500 mm, and an eccentricity
radius of 150 mm. FIG. 11 shows that the average axial velocity of
the solid particles varies with distance through this geometry and
eventually reaches a fairly stable value of 2 m/s within the
undulating pipe. Upon exiting the undulating intake pipe, it can be
seen that the solid particles are then accelerated back to the
expected average velocity of 5 m/s within the straight pipe
section. Without restriction to a theory, it is believed that this
reduction in axial velocity of the solid particles is due to the
solid particles travelling along the periphery of the pipe where
the axial velocity is lower than near the center of the pipe, and
the solid particles being decelerated by impacts with the inner
wall of the intake pipe 10.
[0042] It has been noted in the field that when centrifugal slurry
pumps are operated in series, in close proximity to each other, the
downstream pump will wear more quickly than the upstream pump. One
proposed reason for this is that the particles are accelerated by
the upstream pump and carry added velocity to the downstream pump.
The predicted effect of the helical portion 16 of the intake pipe
10 in reducing the axial velocity of the solid particles may be
used to mitigate the tendency of the downstream pump in a series of
pumps to wear more quickly than the upstream pump. Thus, the intake
pipe 10 of the present invention may be used as an inter-stage pipe
between two centrifugal pumps.
Effect of Helical Portion and Pump Inlet Position on Impeller and
Volute Wear
[0043] The model was also used to qualitatively predict the effect
of the helical portion 16 of the intake pipe 10 on the wear of the
impeller 30 and volute of the centrifugal pump 20. The specific
wear model used in this study was that of Tabakoff-Grant. The
erosion rate is calculated as per the below equations:
E = [ [ 1 + k 2 k 12 sin ( .theta..pi. 2 .theta. 0 ) ] 2 ( V P V 1
) 2 cos 2 .theta. ( 1 - R T 2 ) + ( V P V 2 sin ( .theta. ) ) 4 ] N
.smallcircle. m p ##EQU00001## where : ##EQU00001.2## R T = 1 - V P
V 3 sin ( .theta. ) ##EQU00001.3##
[0044] and:
[0045] k.sub.2=1 if .theta..ltoreq.2.theta..sub.0
[0046] k.sub.2=0 if .theta.>2.theta..sub.0
[0047] E=erosion rate (kg/s)
[0048] k.sub.12, k.sub.2=dimensionless constants
[0049] V.sub.1, V.sub.2, V.sub.3=reference velocities (m/s)
[0050] V.sub.P=relative velocity (m/s)
[0051] .theta.=impact angle (radians)
[0052] .theta..sub.0=impact angle of maximum erosion (radians)
[0053] N=number rate of particle impact on position (s.sup.-1)
[0054] m.sub.P=mass of particle (kg).
The specific coefficient values used in the model are outlined in
Table 1.
TABLE-US-00001 TABLE 1 Coefficient Value Units k.sub.12 5.85
.times. 10.sup.-1 Unitless V.sub.1 159.11 m/s V.sub.2 194.75 m/s
V.sub.3 190.5 m/s .theta..sub.0 25 degrees
[0055] Three different configurations of pump systems were modeled:
a "straight pipe", with a pump inlet axially aligned with the
impeller axis; "configuration 1" which was an intake pipe with a
helical portion, with a pump; and "configuration 2", which was also
an intake pipe with a helical portion. In configuration 1 as shown
in FIG. 12, the pipe outlet and pump inlet were positioned to
introduce the slurry into the pump such that the solid particles
would travel through most of the volute before being discharged
through the pump outlet. In contrast, in configuration 2 as shown
in FIG. 13, the pipe outlet and pump inlet were positioned to
introduce the slurry into the pump such that the solid particles
would bypass most of the volute before being discharged through the
pump outlet. Each configuration was modelled for both a centrifugal
pump with a volute that discharged the slurry at the bottom of the
volute, and a volute that discharged the slurry at the top of the
volute.
[0056] The predicted erosion of the volute and the impeller are
summarized in Table 2, below. FIGS. 14A and 14B illustrate the
predicted erosion patterns of the volute 20 of a centrifugal pump
caused by solid particles of a slurry flowing through a straight
pipe and configuration 2 of the intake pipe 10, respectively, both
with a bottom discharge volute.
TABLE-US-00002 TABLE 2 Straight Pipe-Top Discharge Total Impeller
Erosion 9.71E-04 kg Total Volute Erosion 1.67E-03 kg Straight
Pipe-Bottom Discharge Total Impeller Erosion 1.20E-03 kg Total
Volute Erosion 1.66E-03 kg Undulating Pipe-Top Discharge-Config 1
Total impeller Erosion 7.85E-04 kg Total Volute Erosion 2.32E-03 kg
Undulating Pipe-Bottom Discharge-Config 1 Total Impeller Erosion
6.29E-04 kg Total Volute Erosion 2.49E-03 kg Undulating Pipe-Top
Discharge-Config 2 Total Impeller Erosion 8.38E-04 kg Total Volute
Erosion 1.22E-03 kg Undulating Pipe-Bottom Discharge-Config 2 Total
Impeller Erosion 5.49E-04 kg Total Volute Erosion 1.14E-03 kg Wear
Reduction-Config 1 Total Impeller Erosion 19.2% Total Volute
Erosion -39.4% Wear Reduction-Config 1 Total Impeller Erosion 47.6%
Total Volute Erosion -50.2% Wear Reduction-Config 2 Total Impeller
Erosion 13.7% Total Volute Erosion 27.0% Wear Reduction-Config 2
Total Impeller Erosion 54.2% Total Volute Erosion 31.6%
[0057] These results indicate that the intake pipe of the present
invention may reduce the erosion of both the volute and impeller of
a centrifugal pump, relative to a straight intake pipe. Further,
positioning the pipe outlet and pump inlet to introduce the slurry
into the pump such that the solid particles would bypass most of
the volute may also be advantageous in this regard.
[0058] Without restriction to a theory, it is believed that the
reduction of erosion by using the intake pipe 10 of the present
invention is attributable to a decrease in the impact velocity of
solid particles in the slurry with the leading edge of the impeller
30, as well as the fact that many of the solid particles avoid
impact with the leading edge of the impeller 30 due to the
circumferential velocity of the solid particles imparted by the
intake pipe 10.
[0059] The previous description of the disclosed embodiments is
provided to enable any person skilled in the art to make or use the
present invention. Various modifications to those embodiments will
be readily apparent to those skilled in the art, and the generic
principles defined herein may be applied to other embodiments
without departing from the spirit or scope of the invention. Thus,
the present invention is not intended to be limited to the
embodiments shown herein, but is to be accorded the full scope
consistent with the claims, wherein reference to an element in the
singular, such as by use of the article "a" or "an" is not intended
to mean "one and only one" unless specifically so stated, but
rather "one or more". All structural and functional equivalents to
the elements of the various embodiments described throughout the
disclosure that are known or later come to be known to those of
ordinary skill in the art are intended to be encompassed by the
elements of the claims. Moreover, nothing disclosed herein is
intended to be dedicated to the public regardless of whether such
disclosure is explicitly recited in the claim.
* * * * *