U.S. patent application number 14/783587 was filed with the patent office on 2016-03-03 for pump impeller.
The applicant listed for this patent is WEIR MINERALS AUSTRALIA LTD. Invention is credited to Garry Bruce Glaves, Luis Moscoso Lavagna.
Application Number | 20160061213 14/783587 |
Document ID | / |
Family ID | 52741623 |
Filed Date | 2016-03-03 |
United States Patent
Application |
20160061213 |
Kind Code |
A1 |
Lavagna; Luis Moscoso ; et
al. |
March 3, 2016 |
Pump Impeller
Abstract
An impeller for a pump, the impeller comprising a main body
which in use is rotatable about a central axis, the main body
including a front side and a rear side, the front side having a
generally spherical cap-like or dome-shaped surface with an apex
region in the vicinity of the central axis and a peripheral outer
region in the vicinity of the rear side, a plurality of channels
extending through the main body each having an inlet opening and an
outlet opening, the inlet openings being in the vicinity of the
apex region and the outlet openings being in the vicinity of the
peripheral outer region.
Inventors: |
Lavagna; Luis Moscoso;
(North Ryde, AU) ; Glaves; Garry Bruce;
(Marsfield, AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WEIR MINERALS AUSTRALIA LTD |
Artarmon, New South Wales |
|
AU |
|
|
Family ID: |
52741623 |
Appl. No.: |
14/783587 |
Filed: |
April 10, 2014 |
PCT Filed: |
April 10, 2014 |
PCT NO: |
PCT/AU2014/000397 |
371 Date: |
October 9, 2015 |
Current U.S.
Class: |
415/83 ;
416/91 |
Current CPC
Class: |
F04D 29/2216 20130101;
F04D 29/2294 20130101; F04D 29/426 20130101; F04D 7/04 20130101;
F04D 1/00 20130101; F04D 29/2255 20130101; F04D 29/225
20130101 |
International
Class: |
F04D 29/22 20060101
F04D029/22; F04D 7/04 20060101 F04D007/04; F04D 29/42 20060101
F04D029/42; F04D 1/00 20060101 F04D001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 10, 2013 |
AU |
2013901228 |
Claims
1. An impeller for a pump, the impeller comprising a main body
which in use is rotatable about a central axis, the main body
including a front side and a rear side, the front side having a
generally spherical cap-like or dome-shaped surface with an apex
region in the vicinity of the central axis and a peripheral outer
region in the vicinity of the rear side, a plurality of channels
extending through the main body each having a channel surface, an
inlet opening and an outlet opening, the inlet openings being in
the vicinity of the apex region and the outlet openings being in
the vicinity of the peripheral outer region at least a part of the
channel surface provides for a pumping surface.
2. The impeller according to claim 1, wherein the channels are
curved.
3. (canceled)
4. The impeller according to claim 1, wherein the inlet openings
are spaced around the central axis.
5. The impeller according to claim 1, wherein the outlet openings
are spaced around the peripheral outer region.
6. The impeller according to claim 1, wherein the distance of each
channel with respect to the central axis increases when moving from
the inlet opening to the outlet opening.
7. The impeller according to claim 1, wherein the inlet openings
are generally oval shaped and have a long or major axis, the long
or major axis being inclined to the central axis.
8. The impeller according to claim 1, wherein the outlet openings
are generally oval shaped and have a long or major axis the long or
major axis generally following the periphery of the peripheral
outer region.
9. The impeller according to claim 7, wherein the inlet openings
have a curved leading edge portion.
10. The impeller according to claim 1, wherein the main body
includes a central mount to which a pump drive shaft can be
operatively fitted.
11. The impeller according to claim 1, wherein the rear side
comprises a recessed face.
12. The impeller according to claim 11, including auxiliary
pump-out vanes on the recessed face.
13. The impeller according to claim 12, wherein the main body
includes a cover which overlies the recessed face.
14. A pump intake device for use with an impeller according to
claim 1, the pump intake device comprising an outer section
comprising a conduit having an inner surface and an inner section
having an inner profiled surface which is substantially similar in
profile to part of the impeller surface.
15. The pump intake device according to claim 14, wherein the inner
profiled surface is partially dome shaped.
16. The pump intake device according to claim 14, wherein the inner
surface of the outer section diverges or curves outwardly.
17. The pump intake device according to claim 16, wherein the inner
surface of the outer section and the inner profiled surface of the
inner section provide a continuous curving surface between regions
adjacent opposed end of the device.
18. A pump comprising a pump casing which includes a main casing
part and front side casing part comprising a pump intake device
comprising an outer section comprising a conduit having an inner
surface and an inner section having an inner profiled surface which
is substantially similar in profile to part of the impeller surface
and an impeller mounted within the pump casing, the impeller
comprising a main body which in use is rotatable about a central
axis, the main body including a front side and a rear side, the
front side having a generally spherical cap-like or dome-shaped
surface with an apex region in the vicinity of the central axis and
a peripheral outer region in the vicinity of the rear side, a
plurality of channels extending through the main body each having a
channel surface, an inlet opening and an outlet opening, the inlet
openings being in the vicinity of the apex region and the outlet
openings being in the vicinity of the peripheral outer region at
least a part of the channel surface provides for a pumping
surface.
19. The impeller according to claim 1, wherein the channels have a
cross-section which progressively increases in cross-sectional area
from the inlet openings to the respective outlet openings.
Description
TECHNICAL FIELD
[0001] This disclosure relates generally to impellers for pumps and
more particularly but not exclusively to centrifugal slurry pumps
for handling slurries which are usually a mixture of liquid and
particulate solids, and are commonly encountered in the minerals
processing, sand and gravel and/or dredging industry.
BACKGROUND ART
[0002] Centrifugal slurry pumps generally include a pump housing
having a pumping chamber therein which may be of a volute
configuration with an impeller mounted for rotation within the
pumping chamber. A drive shaft is operatively connected to the pump
impeller for causing rotation thereof, the drive shaft entering the
pump housing from one side. The pump further includes a pump inlet
which is typically coaxial with respect to the drive shaft and
located on the opposite side of the pump housing to the drive
shaft. There is also a discharge outlet typically located at a
periphery of the pump housing.
[0003] The impeller typically includes a hub to which the drive
shaft is operatively connected and at least one shroud. Pumping
vanes are provided on one side of the shroud with discharge
passageways between adjacent pumping vanes. In one form of impeller
two shrouds are provided with the pumping vanes being disposed
therebetween. The pump impeller is adapted to be run at different
speeds to generate the required pressure head.
[0004] Conventional slurry pumps tend to generate turbulence
because of the configuration of the impeller. Conventional
impellers when viewed in cross section have a generally square or
rectangular shape because of shrouds and the position of the
pumping blades relative to those shrouds. The configuration tends
to give rise to the development of a vortex having a "horseshoe"
shape which tends to develop in the passage between adjacent
pumping vanes and is responsible for wear on the blade and
shrouds.
[0005] EP 146027 and US 2003/0215343 disclose pumps which include
an electric motor having a rotor to which an impeller is attached.
In essence the impeller in each of these documents is conventional.
The spherical, or part-spherical, rotor serves to house the magnet
forming part of the electric motor. U.S. Pat. No. 3,476,488
discloses a spherical pump housing, but again the impeller is
essentially conventional in structure.
[0006] DE 344907 discloses a pump which is used in situations where
reverse flows are required, such as in recirculating heating pumps
and pumps in filter systems. The pump has a pump casing 10 with a
chamber therein for receiving a spherical impeller 11 rotatable by
drive shaft 12. The spherical impeller 11 comprises two
hemispherical sections each being associated with a respective flow
channel 14, and each channel 14 being capable of functioning as a
fluid intake channel or a discharge channel depending on the
direction of rotation of the impeller. A series of tubes are
disposed within the impeller extending from one side of the
spherical impeller to the other side. The pumping chamber has
recessed sections 31 which facilitate flow of fluid from one flow
channel to the other intake/discharge channel and therefore the
flow direction is at right angles to the impeller rotation axis and
the tubes have 90.degree. bends therein.
SUMMARY OF THE DISCLOSURE
[0007] In a first aspect, embodiments are disclosed of an impeller
for a pump the impeller comprising a main body which in use is
rotatable about a central axis, the main body including a front
side and a rear side, the front side having a generally spherical
cap like or dome shaped surface with an apex region in the vicinity
of the central axis and a peripheral outer region in the vicinity
of the rear side, a plurality of channels extending through the
main body each having an inlet opening and an outlet opening, the
inlet openings being in the vicinity of the apex region and the
outlet openings being in the vicinity of the peripheral outer
region.
[0008] In certain embodiments, the channels are curved in a
direction between the inlet opening and outlet opening. In certain
embodiments at least a part of the channel surface provides for a
pumping surface. In certain embodiments the distance of each
channel with respect to the central axis progressively increases in
the radial direction when moving from the inlet opening to the
outlet opening.
[0009] In certain embodiments, the inlet openings are spaced around
the central axis. In certain embodiments the outlet openings are
spaced around the peripheral outer region.
[0010] In certain embodiments, the inlet openings are generally
oval or elliptically shaped and have a long or major axis, the long
or major axis being inclined to the central axis.
[0011] In certain embodiments, the outlet openings are generally
oval or elliptically shaped and have a long or major axis the long
or major axis generally following the periphery of the peripheral
outer region.
[0012] In certain embodiments, the inlet openings have a curved
leading edge portion.
[0013] In certain embodiments, the main body includes a central
mount to which a pump drive shaft can be operatively fitted.
[0014] In certain embodiments, the rear side comprises a recessed
face. In certain embodiments auxiliary pump out vanes are provided
on the recessed face. In certain embodiments a cover overlies the
recess face.
[0015] In a second aspect there is provided a pump intake device
for use with an impeller as described in the first aspect, the pump
intake device comprising an outer section comprising a conduit
having an inner surface and an inner section having an inner
profiled surface which is substantially similar in profile to part
of the impeller surface.
[0016] In certain embodiments, the inner surface of the outer
section diverges or curves outwardly. In certain embodiments the
inner surface of the outer section and the inner profiled surface
of the inner section provide a continuous curving surface between
regions adjacent opposed ends of the device.
[0017] In accordance with a third aspect there is provided a pump
comprising a pump casing which includes a main casing part and
front side casing part comprising a pump intake device as described
in the second aspect, and an impeller as described in the first
aspect mounted within the pump casing.
[0018] Other aspects, features, and advantages will become apparent
from the following detailed description when taken in conjunction
with the accompanying drawings, which are a part of this disclosure
and which illustrate, by way of example, principles of inventions
disclosed.
DESCRIPTION OF THE FIGURES
[0019] The accompanying drawings facilitate an understanding of the
various embodiments.
[0020] FIG. 1 is an isometric view of a pump impeller according to
one embodiment of the present disclosure;
[0021] FIG. 2 is an first side elevation of the pump impeller shown
in FIG. 1;
[0022] FIG. 3 is a second side elevation of the pump impeller shown
in FIGS. 1 and 2;
[0023] FIG. 4 is a front elevation of the pump impeller shown in
FIGS. 1 to 3;
[0024] FIGS. 5 and 6 are sectional views of the pump impeller shown
in FIGS. 1 to 4;
[0025] FIG. 7 is a sectional view of a pump impeller according to a
further embodiment;
[0026] FIG. 8 is a sectional view of a pump impeller according to a
further embodiment; and
[0027] FIG. 9 is a schematic view partially in section of a pump
assembly according to one embodiment.
DETAILED DESCRIPTION
[0028] Referring to FIG. 9 of the drawings there is illustrated a
pump assembly 50 which includes a pump 51 having a pump casing 60
which is mounted to a pump casing support or pedestal 55. The pump
casing 60 comprises a main casing part (or volute) 61, a front side
casing part 62 and a rear side casing part 63 which, when assembled
together provide for a pumping chamber 68 located therein. The
front side casing part 62 is in the form of a pump intake device 70
through which the fluid to be pumped enters the pumping chamber 68.
The rear side casing part 62 provides for a seal chamber housing
90. A pump impeller 10 is disposed within the pumping chamber 68
and is operatively connected to a drive shaft 53 for rotation about
a central axis X-X.
[0029] As shown in the Figures, the impeller 10 comprises a main
body 12 with a front side 14 and a rear side 16. The front side 14
has a generally dome-shaped, or spherical cap-like, outer surface
18 (that is, the region of a sphere disposed to one side of a given
plane) having an apex region 20 in the vicinity of the central axis
X-X and a peripheral outer region 22 adjacent the rear side 16. The
outer surface may for example be generally hemispherical in shape
but is not limited to that shape. In use, the apex region 20 is the
forward-most part of the main body 12 and faces the pump inlet when
in an assembled position. As shown schematically in one form shown
in dotted outline in FIG. 8, the impeller 10 is positioned within a
pump housing or casing 50 having an inlet 51 and an outlet 52, the
apex region 20 of the main body facing the inlet 51.
[0030] The impeller 10 further includes a plurality of channels
which extend through the main body 12 of the impeller 10. In the
embodiment shown, there are four separate channels, 25, 26, 27, 28
although in other embodiments two, three, five or six channels are
also possible. Each channel has an inlet opening and an outlet
opening; channel 25 has an inlet opening 31 and an outlet opening
35; channel 26 has an inlet opening 32 and an outlet opening 36;
channel 27 has an inlet opening 33 and an outlet opening 37; and
channel 28 has an inlet opening 34 and an outlet opening 38. As is
best seen in FIGS. 1 and 4, the inlet openings 31, 32, 33 and 34
are in the vicinity of the apex region 20 and are spaced around the
central axis X-X. The inlet openings are generally oval in shape
each having a major axis Y-Y. As shown the major axes Y-Y are
inclined to the central axis X-X and are arranged offset to one
another as well as one behind the other, around the central axis
X-X. Each inlet opening has a curved (or blended) leading edge 39
to facilitate fluid entry. The distance of each channel away from
the central axis X-X progressively increases in a general radial
direction when moving from the inlet openings 31, 32, 33, 34 to the
respective outlet openings 35, 36, 37, 38, for example as can be
seen in dotted outline in FIG. 2 in relation to one exemplary
channel 27. With reference to FIG. 1, the continuation of channel
27 can be seen beyond a bend therein.
[0031] The channels 25, 26, 27, 28 are in the form of a tube or
tube-like formation or passageway, having a generally oval-shaped
cross section which progressively increases in cross-sectional area
when moving in a direction from the inlet openings 31, 32, 33, 34
to the respective outlet openings 35, 36, 37, 38. The configuration
and path of one exemplary channel 25 through the impeller body 12
is illustrated by phantom lines in FIGS. 1 and 4. The configuration
and path of a further exemplary channel 27 is illustrated by
phantom lines in FIG. 2. The configuration and path of a further
exemplary channel 26 is illustrated by phantom lines in FIG. 3.
Only one channel has been illustrated in each of the FIGS. 1, 2, 3
and 4 for reasons of clarity.
[0032] As shown in FIGS. 1 and 4, the channel 25 follows a curved
path from the inlet opening 31 to the outlet opening 35. Each of
the other channels 26, 27, 28 is of similar configuration. The
progressive increase in cross sectional area of the channels 25,
26, 27, 28 is analogous to the shaping of the channels formed
between pumping vanes and shrouds of conventional impellers. The
distinction between the shape of the channels formed in a
conventional impeller and the channels 25, 26, 27, 28 of the
impeller which is the subject of this disclosure, resides in their
oval cross section, which is believed to reduce the formation of
vortices as a fluid moves through the channels 25, 26, 27, 28, as
compared to the situation in conventional impellers, as will now be
described.
[0033] In conventional impellers, strong flow vortices can be
generated in the region of the leading edge of the pumping vanes
and also at the junction of the pumping vane sides and the impeller
shroud side faces. In the conventional apparatus, there is an
abrupt change in direction, or sharp corner, between the face of
the pumping vanes and the face of the shrouds. Such sharp corners
can cause the generation of vortices as pumped fluid flows across
these edges, which in turn results in increased wear in those
regions of the impeller. The curved cross-sectional shape of the
channels 25, 26, 27, 28 in the impeller which is the subject of
this disclosure does not result in the same extent of formation of
such fluid vortices.
[0034] The outlet openings 35, 36, 37 and 38 are also generally
oval shaped having a major axis Z-Z. The major axes Z-Z are
arranged so as to follow around the peripheral outer region one
behind the other and offset to one another.
[0035] The rear side 16 of the main body 12 has a recess or void 40
therein which as shown in FIGS. 7 and 8, and over which a back
cover 45 can be received. As shown, the back cover 45 is generally
frusto-conical in shape having a curved side. Auxiliary expeller
vanes 47 may be provide on the back cover as shown in FIG. 8.
[0036] A drive shaft mount 42 is provided in the main body at the
central axis X-X for fitting the drive shaft 53 thereto (FIG.
8).
[0037] As shown in FIG. 9, the front side casing part 62 is in the
form of a pump intake device 70 which comprises an outer (forward)
section 72 generally shaped in the form of a conduit 73, and an
inner section 74 which is operatively connected to the main casing
part 61. In the form illustrated, the pump intake device 70 is of a
one piece construction. The inner section 74 has an inner profiled
surface 77 which follows closely in shape a part of the surface 18
of the impeller 10, so that in the assembled position there is a
small gap therebetween. As shown in FIG. 9, the outer section 72
has an inner surface 78 which diverges or curves outwardly from the
central axis X-X and smoothly joins the profiled surface 77 which
in turn curves inwardly. The overall inner surface of the intake
device provides for a smooth, continuously-curving surface which
terminates at an end section 75. As shown in the Figure, the pump
intake device 70 is generally bell-shape with convex inner surface
portion in the outer section, and a concave inner surface portion
in the inner section.
[0038] It is believed that the impeller 10 can offer reduced fluid
turbulence and vortices generated when in use, when compared to a
conventional pumping impeller, which in turn will lead to a
relative reduction in wear of the impeller while at the same time
producing similar levels of head pressure and efficiency to that of
a conventional impeller. The reduction in the amount of vortices in
the pumping channels has already been described. In addition, the
skin friction over the spherical or dome shaped front side surface
will be minimised, thus reducing wear which normally occurs as a
result of small particles which become entrained in the boundary
layer of the slurry on the surface of the front side of a moving
impeller. It is believed that the "horseshoe" shaped vortex
developed in use over the pumping vanes of conventional impellers
will be much weaker.
[0039] During use, when the fluid approaches the spherical or domed
shaped surface, the interaction is the smoothest possible due to
sphere/fluid motion characteristics. This reduces impact and
friction at the time the fluid enters into the impeller's channels
25, 26, 27, 28. Each channel opening 31, 32, 33, 34 has an entry
edge with an optimized rounded shape with a curved (or blended)
leading edge to facilitate fluid entry, which allows the fluid to
enter the channel 25, 26, 27, 28 with minimum fluid separation. In
conventional centrifugal impellers, this fluid separation is what
gives origin to the undesired "horseshoe" vortex.
[0040] While points of high turbulence on the entry surface exist,
they are not in the proximity of any other wet surface. For this
reason they do not cause the erosion that typically occurs between
impeller's inlet eye and throatbush. Any points of turbulence are
most likely to be associated with the edges of the impeller
channels, and since these face forward and into the inlet fluid
flowstream only, erosive wear of adjacent physical components is
minimised.
[0041] The impeller does not have a back shroud, for this reason
the void space in the body is covered by a lid or back cover, which
can be plain or contain the back vanes as illustrated in FIG. 8
which are needed to hydraulically seal the gap between the impeller
and the pump liner.
[0042] As mentioned earlier, the outlets of the impeller channels
25, 26, 27, 28 also have an oval shape, and their edges have an
optimized rounded shape to induce a smooth transition
impeller/volute. The purpose is also to reduce the turbulence
generated by the interaction between this impeller outlet surface
and the fluid which is just leaving the impeller's channel.
[0043] Computational Simulation Data
[0044] The shape of impeller which is the subject of this
disclosure, is quite different to the conventional design of a
centrifugal pump impeller which involves two shrouds with pumping
vanes disposed therebetween.
[0045] The level of erosion intensity of a fluid passing into a
centrifugal pump impeller of conventional design was simulated
using Computational Fluid Dynamics (CFD). It was observed that the
maximum value of erosion intensity measured was 7000 units,
especially at the area where the fluid enters the impeller and is
turned into the pumping vane channels (that is, at the eye of
impeller).
[0046] The level of erosion intensity of a fluid passing into the
impeller which is the subject of this disclosure was also simulated
using Computational Fluid Dynamics (CFD). Here, it was observed
that the maximum value of erosion intensity measured was 3600 units
at the rims of the impeller inlets to the channels where the fluid
enters the impeller.
[0047] This computational data indicated that the erosion level for
the impeller, which is the subject of this disclosure, is 49% lower
than the conventional impeller design for similar flow pumping
conditions (including head pressure and flow rate).
[0048] It was further observed that when the rims of inlets to the
channels of the impeller which is the subject of the disclosure,
are made even more blended with the front face of the impeller, it
is possible to reduce the erosion intensity to around 1700 units,
in the area of the rims, which is even lower than the 3600 units of
erosion intensity in the first design simulated.
[0049] Based on such computational data, it is believed that the
impeller which is the subject of this disclosure offers longer wear
life than the conventional impeller design.
[0050] In the foregoing description of preferred embodiments,
specific terminology has been resorted to for the sake of clarity.
However, the invention is not intended to be limited to the
specific terms so selected, and it is to be understood that each
specific term includes all technical equivalents which operate in a
similar manner to accomplish a similar technical purpose. Terms
such as "front" and "rear", "inner" and "outer", "above", "below",
"upper" and "lower" and the like are used as words of convenience
to provide reference points and are not to be construed as limiting
terms.
[0051] The reference in this specification to any prior publication
(or information derived from it), or to any matter which is known,
is not, and should not be taken as, an acknowledgement or admission
or any form of suggestion that prior publication (or information
derived from it) or known matter forms part of the common general
knowledge in the field of endeavour to which this specification
relates.
[0052] In this specification, the word "comprising" is to be
understood in its "open" sense, that is, in the sense of
"including", and thus not limited to its "closed" sense, that is
the sense of "consisting only of". A corresponding meaning is to be
attributed to the corresponding words "comprise", "comprised" and
"comprises" where they appear.
[0053] In addition, the foregoing describes only some embodiments
of the invention(s), and alterations, modifications, additions
and/or changes can be made thereto without departing from the scope
and spirit of the disclosed embodiments, the embodiments being
illustrative and not restrictive.
[0054] Furthermore, invention(s) have been described in connection
with what are presently considered to be the most practical and
preferred embodiments, it is to be understood that the invention is
not to be limited to the disclosed embodiments, but on the
contrary, is intended to cover various modifications and equivalent
arrangements included within the spirit and scope of the
invention(s). Also, the various embodiments described above may be
implemented in conjunction with other embodiments, e.g., aspects of
one embodiment may be combined with aspects of another embodiment
to realize yet other embodiments. Further, each independent feature
or component of any given assembly may constitute an additional
embodiment.
TABLE-US-00001 Table of Parts Pump impeller 10 Main body 12 Front
side 14 Rear side 16 Dome shaped surface 18 Apex region 20
Peripheral outer region 22 Central axis X-X Channels 25 26 27 28
Inlet openings 31 32 33 34 Outlet openings 35 36 37 38 Leading edge
39 Oval shape Major axis Y-Y Major axis Z-Z Recess/void 40 Drive
shaft mount 42 Back cover 45 Auxiliary vanes 47 Pump assembly 50
Pump 51 Pump casing 60 Drive shaft 53 Pedestal 55 Main casing part
61 Front side casing part 62 Rear side casing part 63 Pumping
chamber 68 Pump intake device 70 Discharge outlet 69 Seal chamber
housing 90 Outer section 72 Conduit 73 Inner section 74 Inner
profiled surface 77 Inner surface 78 End section 75
* * * * *