U.S. patent application number 17/688818 was filed with the patent office on 2022-08-25 for rotary parts for a slurry pump.
The applicant listed for this patent is Weir Minerals Australia Ltd, Weir Minerals Europe Limited. Invention is credited to Pavol Loderer, Craig Ian Walker.
Application Number | 20220268293 17/688818 |
Document ID | / |
Family ID | 1000006320653 |
Filed Date | 2022-08-25 |
United States Patent
Application |
20220268293 |
Kind Code |
A1 |
Loderer; Pavol ; et
al. |
August 25, 2022 |
Rotary Parts For A Slurry Pump
Abstract
A rotary part being an impeller or expeller for a pump which can
be rotated in a forward direction about a rotation axis X-X. The
rotary part comprises a shroud having an outer peripheral edge
portion and opposed first, and second faces, a plurality of
expelling vanes projecting from one or more of the second faces of
the shroud, each expelling vane having an inner side and an outer
side which is at or near the outer peripheral edge portion of the
shroud, the expelling vanes extending in a direction between the
rotation axis X-X towards the outer peripheral edge portion of the
shroud, each expelling vane further including a leading side facing
in the forward direction and having an inner edge and an outer
edge, a trailing side facing in a rearward direction and an up per
side spaced from the outer face of the shroud. The leading side
includes a forwardly inclined section which is inclined forwardly
from a radial line Y-Y extending from the rotation axis X-X and
which passes through the inner edge of the leading side.
Inventors: |
Loderer; Pavol; (Todmorden,
GB) ; Walker; Craig Ian; (Warriewood, AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Weir Minerals Australia Ltd
Weir Minerals Europe Limited |
Artarmon NSW
Todmorden |
|
AU
GB |
|
|
Family ID: |
1000006320653 |
Appl. No.: |
17/688818 |
Filed: |
March 7, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15755476 |
Feb 26, 2018 |
11268533 |
|
|
PCT/AU2016/050798 |
Aug 26, 2016 |
|
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17688818 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 29/2266 20130101;
F04D 7/045 20130101; F04D 29/2288 20130101 |
International
Class: |
F04D 29/22 20060101
F04D029/22; F04D 7/04 20060101 F04D007/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 26, 2015 |
AU |
2015903450 |
Claims
1-20. (canceled)
21. An impeller for a pump which can be rotated in a forward
direction about a rotation axis X-X; the impeller comprising: two
shrouds, one being a front shroud, the other being a back shroud,
pumping vanes extending between the shrouds, the front and back
shrouds each having an outer peripheral edge portion and opposed
inner and outer faces, a plurality of expelling vanes extending
along the outer face of at least one of the front shroud and back
shroud each expelling vane having an inner side and an outer side
which is at or near the outer peripheral edge portion of the at
least one of the front and back shroud, the expelling vanes
extending in a direction between the rotation axis X-X towards the
outer peripheral edge portion of the at least one of the front and
back shroud, each expelling vane further having: a leading side
facing in the forward direction and having an inner edge that is
the innermost edge of the expelling vane and an outer edge that is
an outermost edge of the expelling vane, a trailing side facing in
a rearward direction, and an upper side spaced from the outer face
of the at least one of the front and back shroud, characterised in
that the leading side includes a forwardly inclined section which
is inclined forwardly from a radial line Y-Y extending from the
rotation axis X-X and which passes through the inner edge of the
leading side, the forwardly inclined section extending from the
inner edge towards the shroud outer peripheral edge portion of the
at least one of the front and back shroud, and the forwardly
inclined section having a profile which is linear.
22. The impeller according to claim 21, characterised in that the
forwardly inclined section extends from the inner edge and
terminates at the outer edge of the leading side.
23. The impeller according to claim 21, characterised in that the
forwardly inclined section is inclined at an angle of up to
30.degree. from the radial line Y-Y.
24. The impeller according to claim 21, characterised in that the
forwardly inclined section is inclined at an angle of from
4.degree. to 15.degree. from the radial line Y-Y.
25. The impeller according to claim 21, characterised in that the
forwardly inclined section is inclined at an angle of from
4.degree. to 8.degree. from the radial line Y-Y.
26. The impeller according to claim 21, characterised in that the
forwardly inclined section is inclined at an angle of 4.degree.
from the radial line Y-Y.
27. The impeller according to claim 21, characterised in that the
upper side has a main surface, the distance between the shroud
outer face and the main surface being 0.1 to 0.3 D, where D is the
diameter of the shroud.
28. The impeller according to claim 21, characterised in that the
pumping vanes are backwardly sloped.
Description
TECHNICAL FIELD
[0001] This disclosure relates generally to rotary parts for
centrifugal slurry pumps. The rotary parts may for example be in
the form of impellers, or in the form of expellers which are used
in hydrodynamic seals. Slurries are usually a mixture of liquid and
particulate solids, and are commonly found in minerals processing,
sand and gravel and/or dredging industry.
BACKGROUND ART
[0002] Centrifugal slurry pumps of one type generally include an
outer pump casing which encases a liner which has a pumping chamber
therein which may be of a volute, semi volute or concentric
configuration. An impeller is 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 casing 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 casing to the drive shaft.
There is also a discharge outlet typically located at a periphery
of the pump casing. The liner includes a main liner (sometimes
referred to as the volute) and front and back side liners which are
encased within the outer pump casing.
[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. The impeller may be of
the closed type where two shrouds are provided with the pumping
vanes being disposed therebetween. The shrouds are often referred
to as the front shroud adjacent the pump inlet and the back shroud.
In some applications the impeller may be of the "open" face type
which comprises one shroud only.
[0004] One of the major wear areas in the slurry pump is the front
and back side-liners. Slurry enters the impeller in the centre or
eye, and is then flung out to the periphery of the impeller and
into the pump casing. Because there is a pressure difference
between the casing and the eye, there is a tendency for the slurry
to try and migrate into a gap which is between the side-liners and
the impeller, resulting in high wear on the side-liners.
[0005] In order to reduce the driving pressure on the slurry in the
gap, as well as create a centrifugal field to expel particles, it
is common for slurry pumps to have auxiliary or expelling vanes on
the front shroud of the impeller. Auxiliary or expelling vanes may
also be provided on the back shroud. The expelling vanes rotate the
slurry in the gap creating a centrifugal field and thus reducing
the driving pressure for the returning flow, reducing the flow
velocity and thus the wear on the side-liner. The purpose of these
auxiliary vanes is to reduce flow re-circulation through the gap.
These auxiliary vanes also reduce the influx of relatively large
solid particles in this gap. The outer section of these auxiliary
vanes gives rise to a fluid flow system with strong vortices, which
is responsible for erosion occurring on the vanes themselves and on
the lining surface directly in front of the vanes. Current
auxiliary vanes are usually of a quadrangular cross section. The
corners of this quadrangular shape give origin to sudden changes in
flow direction which can result in the formation of vortices.
[0006] A major issue for slurry pumps is the wear of the
side-liner. In many applications the side-liner is the weakest
point in the pump, wearing out before any other part. Much of the
wear on the side-liner is a result of the flow generated by the
rotating auxiliary vanes. In particular, there is wear from the tip
or outer edge of the auxiliary vanes due to the creation of fluid
vortices and entrained particles.
[0007] Another example of a pump rotary part is an expeller (also
sometimes referred to as repellers). Expellers are used in
hydrodynamic centrifugal seal assemblies. Expellers typically
comprise an inner section which is mounted for rotation with the
drive shaft and an outer section or shroud which is disc-like in
structure. The expeller is disposed within a seal chamber which is
in communication with the pump chamber via a passageway.
[0008] The expeller includes a plurality of expelling vanes which
extend from the inner section and terminate at the outer peripheral
edge of the outer section. The vanes are spaced apart from one
another in the circumferential direction.
[0009] The centrifugal seal assembly is usually used in conjunction
with a main seal apparatus which may be in the form of packings or
lip seals or other types of seals.
[0010] Shaft seal assemblies of this general type for centrifugal
pumps are known. The rotating expeller generates a dynamic pressure
at its periphery. During rotation liquid within the seal chamber is
forced to rotate with the device. This pressure helps to counter
balance the pressure generated from the pump impeller. The reduced
pressure at the drive shaft permits the main seal apparatus to
function as low pressure seal and thereby improve the seal life.
The purpose of the main shaft seal is to prevent fluid leakage when
the pump has stopped.
[0011] Properly applied centrifugal seal assemblies can generate
sufficient pressure to totally counter balance the pump pressure.
In this situation the pumped fluid will remain clear of the pump
shaft and the main shaft seal apparatus can run "dry" under these
ideal conditions. To provide cooling and lubrication it may be
necessary to use some type of lubrication which may be in the form
of grease or water from an external source.
[0012] In operation, the rotating expeller generates a rotating
fluid field in the seal chamber. When it is in the form of a
slurry, the rotating fluid can give rise to wear on various
components of the seal.
SUMMARY OF THE DISCLOSURE
[0013] In a first aspect, embodiments are disclosed of a rotary
part for a pump which can be rotated in a forward direction about a
rotation axis X-X; the rotary part comprising a shroud having an
outer peripheral edge portion and opposed first and second faces, a
plurality of expelling vanes projecting from one or more of the
second faces of the shroud, each expelling vane having an inner
side and an outer side which is at or near the outer peripheral
edge portion of the shroud, the expelling vanes extending in a
direction between the rotation axis X-X towards the outer
peripheral edge portion of the shroud, each expelling vane further
having a leading side facing in the forward direction and having an
inner edge and an outer edge, a trailing side facing in a rearward
direction and an upper side spaced from the outer face of the
shroud, wherein the leading side includes a forwardly inclined
section which is inclined forwardly from a radial line Y-Y
extending from the rotation axis X-X and which passes through the
inner edge of the leading side.
[0014] In certain embodiments, the forwardly inclined section has a
profile which is generally linear.
[0015] In certain embodiments, the forwardly inclined section has
an inner end and an outer end and extends from the inner edge
towards the shroud outer peripheral edge portion.
[0016] In certain embodiments, the forwardly inclined section
extends from the inner edge and terminates at the outer edge of the
leading side.
[0017] In certain embodiments, the forwardly inclined section
extends from the inner edge and terminates at the outer end which
is at an intermediate region which is in spaced relation from the
outer peripheral edge portion of the shroud. The leading side
further including a trailing section which extends rearwardly from
the outer end at the intermediate region of the forwardly inclined
section. The trailing section terminating at the outer peripheral
edge portion. In certain embodiments the trailing section includes
a curved section which curves rearwardly from the outer end. In
certain embodiments the leading side of the trailing section is
curved. In certain embodiments the outer edge of the trailing
section terminates at the outer peripheral edge portion of the
shroud but in other embodiments the outer edge may be spaced from
the outer peripheral edge portion.
[0018] In certain embodiments the leading side of the trailing
section is linear and extends from the outer end to the outer
peripheral edge portion.
[0019] In certain embodiments there is further provided a plurality
of spaced apart projections on the trailing section and extending
rearwardly of the trailing side.
[0020] In certain embodiments the outer end is closer to the outer
peripheral edge portion than to the central axis.
[0021] In certain embodiments, the forward inclined section is
inclined at an angle of up to 30.degree. from the radial line
Y-Y.
[0022] In certain embodiments, the inclined angle is from 4.degree.
to 15.degree..
[0023] In certain embodiments, the rotary part comprises an
impeller. In this particular embodiment the inclined angle is from
4.degree. to 8.degree. and in certain embodiments about
4.degree..
[0024] In certain embodiments, the impeller which comprises two
shrouds, one being a front shroud, the other being a back shroud,
the pumping vanes extending between the shrouds, each shroud having
an inner face and an outer face, the expelling vanes being on the
outer face of the front and/or back shroud.
[0025] In certain embodiments, the rotary part is an expeller for
use in a hydrodynamic seal. In certain embodiments the inclined
angle is from 4.degree. to 8.degree. and in certain embodiments
about 4.degree..
[0026] In certain embodiments, the upper side has a main surface,
the distance between the shroud face and the main surface being 0.1
to 0.3 D, where D is the diameter of the shroud.
[0027] In certain embodiments, the forwardly inclined section
extends from the inner edge to the intermediate region a distance
from 0.65 to 0.95 D, where D is the diameter of the shroud.
[0028] In certain embodiments, the pumping vanes are backwardly
sloped.
[0029] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Notwithstanding any other forms which may fall within the
scope of the method and apparatus as set forth in the Summary,
specific embodiments of the method and apparatus will now be
described, by way of example, and with reference to the
accompanying drawings in which:
[0031] FIG. 1 is a schematic partial cross-sectional side elevation
of one form of a pump apparatus;
[0032] FIG. 2 is a more detailed schematic partial cross-sectional
side elevation of a pump apparatus similar to that shown in FIG.
1;
[0033] FIG. 3 is a rear elevational view of a pump impeller,
according to one embodiment of the present disclosure with an arrow
showing the direction of rotation;
[0034] FIG. 4 is a front elevational view of a pump impeller
according to another embodiment of the present disclosure with an
arrow showing the direction of rotation;
[0035] FIG. 5 is a sectional view taken along the line A-A in FIG.
4;
[0036] FIG. 6 is a schematic partial cross-section of a pump with a
typical centrifugal or hydrodynamic seal assembly;
[0037] FIG. 7 is a sectional side elevation of an expeller for the
hydrodynamic seal assembly of FIG. 5; and
[0038] FIG. 8 is a front elevation of an expeller according to a
further embodiment, and
[0039] FIG. 9 is an isometric view of a pump impeller according to
another embodiment of the present disclosure;
[0040] FIG. 10 is a rear elevational view of the pump impeller
shown in FIG. 9;
[0041] FIG. 11 is an isometric view of a pump impeller according to
another embodiment of the present disclosure from one side;
[0042] FIG. 12 is an isometric view of the pump impeller shown in
FIG. 11 from the other side;
[0043] FIG. 13 is a rear elevational view of the impeller shown in
FIGS. 11 and 12, and
[0044] FIG. 14 is a similar view to that of FIG. 13 showing certain
angles and dimensions.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0045] Referring in particular to FIG. 1 of the drawings, there is
generally illustrated pump apparatus 100 comprising a pump 10 and
pump housing support in the form of a pedestal or base 112 to which
the pump 10 is mounted. Pedestals are also referred to in the pump
industry as frames. The pump 10 generally comprises an outer casing
22 that is formed from two side casing parts or sections 23, 24
(sometimes also known as the frame plate and the cover plate) which
are joined together about the periphery of the two side casing
sections 23, 24. The pump 10 is formed with side openings one of
which is an inlet hole 28 there further being a discharge outlet
hole 29 and, when in use in a process plant, the pump is connected
by piping to the inlet hole 28 and to the outlet hole 29, for
example to facilitate pumping of a mineral slurry.
[0046] The pump 10 further comprises a pump inner liner 11 arranged
within the outer casing 22 and which includes a main liner 12 and
two side liners 14, 30. The side liner (or back liner) 14 is
located nearer the rear end of the pump 10 (that is, nearest to the
pedestal or base 112), and the other side liner (or front liner) 30
is located nearer the front end of the pump. The side liner 14 is
sometimes referred to as the frame plate inner insert and the side
liner 30 is sometimes referred to as the throatbrush. The main
liner comprises two side openings therein.
[0047] As shown in FIG. 1 the two side casing parts 23, 24 of the
outer casing 22 are joined together by bolts 27 located about the
periphery of the casing parts 23, 24 when the pump is assembled for
use. In some embodiments the main liner 12 can also be comprised of
two separate parts which are assembled within each of the side
casing parts 23, 24 and brought together to form a single main
liner, although in the example shown in FIG. 1 the main liner 12 is
made in one-piece, shaped similar to a car tyre. The liner 11 may
be made of materials such as rubber, elastomer or of metal.
[0048] When the pump is assembled, the side openings in the main
liner 12 are filled by or receive the two side liners 14, 30 to
form a continuously-lined pumping chamber 42 disposed within the
pump outer casing 22. A seal chamber housing 114 encloses the side
liner (or back liner) 14 and is arranged to seal the space or
chamber 118 between drive shaft 116 and the pedestal or base 112 to
prevent leakage from the back area of the outer casing 22. The seal
chamber housing takes the form of a circular disc section and an
annular section with a central bore, and is known in one
arrangement as a stuffing box 117. The stuffing box 117 is arranged
adjacent to the side liner 14 and extends between the pedestal 112
and a shaft sleeve and packing that surrounds the shaft 116.
[0049] As shown in FIGS. 1 and 2 an impeller 40 is positioned
within the main liner 12 and is mounted or operatively connected to
the drive shaft 116 which is adapted to rotate about a rotation
axis X-X. A motor drive (not shown) is normally attached by pulleys
to an exposed end of the shaft 116, in the region behind the
pedestal or base 112. The rotation of the impeller 40 causes the
fluid (or solid-liquid mixture) being pumped to pass from a pipe
which is connected to the inlet hole through the pumping chamber 42
which is within the main liner 12 and the side liners 14, 30 and
then out of the pump via the discharge outlet hole.
[0050] As shown in particular in FIG. 2, the front liner 30 (or
throatbrush) includes a cylindrically-shaped delivery section 32
through which slurry enters the pumping chamber 42 when the pump is
in use. The delivery section 32 has a passage 33 therein with a
first, outermost end 34 operatively connectable to a feed pipe (not
shown) and a second, innermost end 35 adjacent the chamber 42. The
front liner 30 further includes a side wall section 15 which mates
in use with main liner 12 to form and enclose the chamber 42, the
side wall section 15 having an inner face 37. The second end 35 of
the front liner 30 has a raised lip 38 thereat, which is arranged
in a close facing relationship with the impeller 40 when in an
assembled position. The back liner 14 comprises a disc-like body
having an outer edge which mates with the main liner and an inner
face 16.
[0051] The impeller 40 includes a hub 41 from which a plurality of
circumferentially spaced pumping vanes 43 extend. An eye portion 47
extends forwardly from the hub 41 towards the passage 33 in the
front liner 30. The impeller 40 further includes a front shroud 50
and a back shroud 51, the vanes 43 being disposed and extending
therebetween and an impeller inlet 48. The hub 41 extends through a
hole 17 in back liner 14.
[0052] The front shroud 50 includes an inner face 55, an outer face
54 and a peripheral edge portion 56. The back shroud 51 includes an
inner face 53, an outer face 52 and a peripheral edge portion 57.
The front shroud 50 includes an inlet 48, being the impeller inlet
and the vanes 42 extend between the inner faces of the shrouds 50,
51. The shrouds are generally circular or disc-shaped when viewed
in elevation; that is in the direction of rotation axis X-X.
[0053] As illustrated in FIG. 2, each shroud has a plurality of
auxiliary or expelling vanes on the outer faces 52, 54 thereof,
there being a first group of auxiliary vanes 60 on the outer face
54 of the front shroud 50 and a second group of auxiliary vanes 61
on the outer face 52 of the back shroud 51.
[0054] FIGS. 3 and 4 illustrate two embodiments of impeller 40. In
FIG. 3 auxiliary or expelling vanes 61 are shown on the back shroud
51 and in FIG. 4 auxiliary or expelling vanes 60 are shown on the
front shroud. In the following description the same reference
numerals are used to identify the same features of the vanes 60 and
61. The auxiliary or expelling vanes 60 on the front shroud and
vanes 61 on the back shroud comprise a leading side 66, and a
trailing side 67 with respect to the direction of rotation as well
as an upper side 69, an inner side 63 and an outer side 65. The
upper side 69 has a main surface 71. The main surface 71 is
generally flat or planar and is generally in a plane parallel with
the shroud outer surface 52, 54. FIG. 3 illustrates the expelling
vanes 61 on the back (or rear) shroud of the impeller 40, and FIG.
3 illustrates the expelling vanes 60 on the front shroud 50. As
shown in FIGS. 4 and 5, the trailing side 67 may have an inclined
surface or wall 73 which is inclined relative to both the upper
surface 71 of the upper side 69, and to the outer face 54 of the
front shroud 50. The leading side 66 includes an inner edge 62, an
outer edge 64, and has a main surface 77 which extends generally at
right angles to the upper surface 71 and to the outer face 52, 54.
The outer edge 64 is at the outer peripheral edge portion 57 of the
back shroud 51, and follows its arcuate contour. In other
embodiments, the outer edge of the expelling vanes may not extend
completely to the outer edge of the shroud. The leading and
trailing sides 66, 67 of the auxiliary vanes 60 are generally
parallel to one another in the embodiments shown in FIG. 3 but in
the embodiment of FIG. 4 they are inclined with respect to one
another.
[0055] The leading side 66 comprises a forwardly inclined section
68 which extends from the inner edge 62 of the expelling vanes 60
and 61. The forwardly inclined section 68 has a generally linear
profile. In the embodiments of FIGS. 2 and 3, the forwardly
inclined section 68 extends from the inner edge 62 to the outer
edge 64 which is located at the shroud peripheral edge portion 57.
In the embodiment of FIG. 2, the expelling vanes 61 are on the
outer face 54 of the back shroud 51. In the embodiment of FIG. 4,
the expelling vanes are on the outer face 54 of the front shroud
50. In other embodiments the outer edge 64 is spaced from the
shroud peripheral edge portion 57.
[0056] Another form of pumping apparatus is partially illustrated
in FIG. 6. Referring to FIG. 6 of the drawings, there is shown pump
apparatus 100 including a pump 10, the pump comprising a pump
casing 22 and a liner 11 with a pumping chamber 42 therein. The
pump 10 further includes a pump impeller 40, the impeller being
mounted for rotation on a drive shaft 116 and disposed within
pumping chamber 42.
[0057] To one side of the pump casing 22 is a centrifugal seal
assembly 82 which includes a rotatable seal device or expeller 83.
This is illustrated in FIG. 7. The seal device or expeller 83
comprises a generally circular (or disc-shaped) main body 84 having
a main surface 81 and opposed surface 93, an inner section 85 which
is mounted to the drive shaft 116 and an outer section or shroud 86
which in the form shown is disc-like in structure with an outer
peripheral edge portion 91. The expeller 83 is mounted to the drive
shaft 116 for rotation therewith. The expeller 83 is disposed
within a seal chamber 87 (FIG. 6) which is in fluid communication
with the pumping chamber 42 via passageway 88.
[0058] The expeller 83 includes a plurality of expelling vanes 89
on surface 81 of the main body 84 and which extend from the inner
section 85 of the main body 84 and terminate at the outer
peripheral edge 91 of the outer section or shroud 86. The expelling
vanes 89 are spaced apart from one another in the circumferential
direction. The expelling vanes are clearly illustrated in FIG.
8.
[0059] The centrifugal seal assembly 82 is used in conjunction with
a main seal apparatus 90 which may be in the form of packings, as
shown, or lip seals or other types of seals.
[0060] One form of the expelling vanes is illustrated in FIG. 8 and
described below.
[0061] With reference in particular to FIG. 8 the expelling vanes
89 of expeller 83 are described. The vanes 89 comprise a leading
side 166, and a trailing side 167 with respect to the direction of
rotation, as well as an upper side 169, an inner side 163 and an
outer side 165. The upper side 169 has a main surface 171. The main
surface 171 is generally flat or planar and is generally in a plane
parallel with surface 81 of the main body 84. The leading side 166
includes an inner edge 162, an outer edge 164, and has a main
surface 177 which extends generally at right anglers to the upper
surface 171 and to the surface 81. The outer edge 164 is at an
outer peripheral edge portion 91 of the main body 84. In other
embodiments, the outer edge of the expelling vanes may not extend
completely to the outer edge portion 91. The leading and trailing
sides 166, 167 of the auxiliary vanes 89 are generally parallel to
one another.
[0062] The leading side 166 comprises a forwardly inclined section
168 which extends from the inner edge 162 of the expelling vanes
89. The forwardly inclined section 168 has a generally linear
profile. In the embodiment of FIG. 8, the forwardly inclined
section 168 extends from the inner edge 162 to the outer edge 164
which is located at outer edge portion 91.
[0063] As shown in FIGS. 4, 5 and 8 the angle A of the forwardly
inclined section 168 of the leading side with respect to a radial
line Y-Y extending in the direction of line Z-Z from the rotation
axis and passing through the inner edge of the leading side can
vary. The angle of inclination is a balance between improved wear
against sealing efficiency. In the embodiment illustrated in FIG. 3
the angle A is 15.degree.. In the embodiments illustrated in FIG. 4
the angle A is 15.degree.. In the embodiment illustrated in FIG. 8
the angle A is 4.degree.. Furthermore, the inclined section of the
leading side and the trailing side may be inclined at an angle B
with respect to one another. As shown in FIG. 4 the angle B is
5.degree.. In the embodiment shown in FIGS. 4 and 5 the trailing
side has an inclined surface which is inclined at an angle C which
in the embodiment shown is 30.degree.. This is best seen in FIG.
5.
[0064] FIGS. 9 and 10 illustrate a further embodiment of impeller
in which auxiliary vanes 61 are shown on the back shroud 51 and
comprise a leading side 66, and a trailing side 67 with respect to
the direction of rotation, as well as an upper side 69, an inner
side 63 and an outer side 65. The upper side 69 has a main surface
71. The main surface 71 is generally flat or planar and is
generally in a plane parallel with the shroud outer surface 52. The
leading side 66 includes an inner edge 62, an outer edge 64, and
has a main surface 71 which extends generally at right angles to
the upper surface 71 and to the outer face 52. The outer edge 64 is
at the outer peripheral edge portion 57 of the back shroud 51, and
follows its arcuate contour. In other embodiments, the outer edge
of the expelling vanes may not extend completely to the outer edge
of the shroud. The leading and trailing sides 66, 67 of the
auxiliary vanes 61 are generally parallel to one another.
[0065] The leading side 66 comprises a forwardly inclined section
68 which extends from the inner edge 62 of the expelling vanes 61
and a trailing section 75. The forwardly inclined section 68 has a
generally linear profile. The forwardly inclined section 68 has an
inner end 77 which is at the inner edge 62 and an outer end 78.
[0066] In the embodiment of FIGS. 9 and 10, the forwardly inclined
section 68 extends from the inner edge 62 and terminates at the
outer end 78 which is remote from the inner edge 62 and which is
spaced from the outer peripheral edge portion 57 of the shroud 51.
In this embodiment, the trailing section 75 extends from the outer
end 69 at an intermediate region 74 to the outer peripheral edge
portion 57. The intermediate region 74 provides for a junction
between the inclined section 68 and trailing section 75. As
illustrated in FIGS. 2 to 4, the forwardly inclined section 68 is
linear and extends in the direction of line Z-Z which is forwardly
inclined with respect to radial line Y-Y which passes through the
inner edge 62.
[0067] The trailing section includes a curved section 76 in which
the leading side 66 in this section curves rearwardly from the
outer end 69 at the intermediate region 74 towards the outer
peripheral edge portion 57.
[0068] The vanes 61 in FIGS. 9 and 10 are shown on the rear or back
shroud 51 but it will be understood that the vanes could be on the
front shroud. The vanes may be on one shroud only or on both
shrouds.
[0069] In the embodiment shown there are 8 vanes 61 on the back
shroud 51. The forward angle of inclination of the forwardly
inclined section 68 is about 15.degree.. The vane width between the
leading and trailing sides is about 0.03D where D is the outer
diameter of the impeller shroud. The vanes have a height which is
the distance from the shroud face to the upper side of about 0.01D.
The radius of curvature of the curved section 76 is about 0.8D. The
intermediate region 74 is about 0.9D.
[0070] FIGS. 11 and 12 illustrate a further embodiment of impeller.
In this embodiment a plurality of auxiliary vanes 61 are arranged
on the back shroud 51 on the outer face 52 thereof. In this
embodiment each vane comprises a leading side 66 and a trailing
side 67 with respect to the direction of rotation of the impeller.
Each vane further comprises an upper side 69, an inner side 63 and
an outer side 65, the upper side 69 having a main surface 71. The
main surface 71 is generally flat or planar and is generally in a
plane parallel with the shroud outer surface 52. The leading side
66 includes an inner edge 62, an outer edge 64, and has a main
surface 71 which extends generally at right angles to the upper
surface 71 and to the outer face 52. The outer edge 64 is at the
outer peripheral edge portion 57 of the back shroud 51. In other
embodiments, the outer edge of the expelling vanes may not extend
completely to the outer edge of the shroud. The leading and
trailing sides 66, 67 of the auxiliary vanes 61 are generally
parallel to one another.
[0071] The leading side 66 comprises a forwardly inclined section
68 which extends from the inner edge 62 of the expelling vanes 61
and a rearwardly inclined section 75 which inclines rearwardly with
respect to the forwardly inclined section 68. The forwardly
inclined section 68 has a generally linear profile. The forwardly
inclined section 68 has an inner end 77 at the inner edge 62 and an
outer end 78. In this embodiment the forwardly inclined section 68
extends from the inner edge 62 and terminates at an outer end 78
which is remote from the inner edge 62 and which is spaced from the
outer peripheral edge portion 57 of the shroud 51. In this
embodiment, the trailing section 75 extends from the outer end 78
at an intermediate region 74 to the outer peripheral edge portion
57. The intermediate section 74 provides for a junction between the
inclined section 68 and trailing section 75. As illustrated in
FIGS. 2 to 4, the forwardly inclined section 68 is linear and
extends in the direction of line Z-Z which is forwardly inclined
with respect to radial line Y-Y which passes through the inner edge
62.
[0072] In this embodiment the trailing section 75 has a linear
leading side which extends from the outer end 69 at the junction 74
to the outer peripheral edge portion 57 of the shroud.
[0073] As shown in FIGS. 11 and 12 the auxiliary vanes 60 have
associated therewith a plurality of projections 95, 96 which extend
generally laterally from the trailing side 67 of the auxiliary
vanes 60, the projections being spaced apart along the length
thereof. The projections 95, 96 may extend at 90.degree. to the
trailing side 67 or to a radial line extending from the rotation
axis X-X. Projections of this type are described in patent
specification WO 2016/040999, the contents of which are
incorporated into this specification by cross reference.
[0074] As shown, the projections are generally oblong in shape and
include inner and outer sides, a top side and an end side. The
surfaces of each of the sides are generally flat or planar. The
projections have a height measured from the outer face 52 of the
shroud 50 to the top side 99 of the projection, and the auxiliary
vanes have a height measured from the outer face 52 of the shroud
50 to the main surface 71 of the upper side of the auxiliary vane.
The projections have a length taken from the trailing side 67 of
the auxiliary vane 60 with which the projection is associated to
its end side 86. As shown, the length of the projection associated
with the auxiliary vane is substantially the same. In the
embodiment shown, the projections 95, 96 are spaced from one
another and positioned at the trailing side 67 of the auxiliary
vane 60 both closer to the outer edge 65 than the inner edge 63. In
this embodiment the top side 94 of the projections is spaced
inwardly from the main surface 71 of the upper side 69 of the
auxiliary vane 60.
[0075] As can be seen the leading side in this embodiment is
generally V-shaped although one arm of the V is longer than the
other. Further as it is apparent from FIG. 11 of the shroud 51 has
an inclined surface or frusto-conical shaped surface 59 in an inner
region which surrounds the hub 41. The vanes in this region taper
in height so as to blend with this surface 59. The provision of the
rearwardly extending section reduces the strength of a vortex
generated at the outer edge or tip of the vane. In use conventional
auxiliary vanes, there is an outward radial flow in the region of
the trailing side of the auxiliary vane which intersects with a
tangential flow at the outer edge or vane top of the auxiliary
vane. It is these intersecting flows which generate a strong tip
vortex. It is this tip vortex which causes significant wear on the
respective impeller when it is exposed to a particulate slurry
material during operating of the impeller in a pump.
[0076] The projections provide that the radial outflow on the
shroud is disturbed or deflected and is thus reduced. There is a
reduction on the strength of the vortex generated at the outer edge
or tip of the vane relative to conventional expelling vanes. This
leads to a reduction in the outflow velocity and reduces the wear
rate at the tip of the vane.
[0077] FIG. 14 identifies various angles and dimensions relating to
the embodiment shown in FIGS. 11 to 13. Set out below are details
of these dimensions and angles and ranges for certain
dimensions.
[0078] P is the angle of inclination of the forwardly inclined
section.
[0079] R is the angle of inclination of the rearwardly extending
section.
[0080] N is the distance from the leading side of the trailing
section to the remote end of the projections.
[0081] M is the width of the projections.
[0082] F is the width of the vane.
[0083] G is the distance from the outer end to the central
axis.
[0084] K is the distance from the inner side of the inner
projection to the central axis.
[0085] L is the distance from the inner side of the outer
projection to the central axis.
[0086] D is the diameter of the shroud.
[0087] H is the radius of curvature of the junction between the
outer end of the leading side of the forwardly inclined section and
the trailing section.
[0088] E is the distance from the inner edge of the leading side of
the forwardly inclined section to the central axis.
[0089] J is the radius of curvature of the outer edge of the
leading side of the vane.
TABLE-US-00001 P = 15.degree. R = 6.degree. N = 0.04 D M = 0.012 D
F = 0.03 D K = 0.85 D/2 G = 0.75 D/2 L = 0.92 D/2
[0090] P may be in the range from 4.degree. to 30.degree..
[0091] G may be in the range from 0.6 D/2 to 0.9 D/2.
[0092] R may be in the range from 3.degree. to 10.degree..
[0093] The length of the forwardly inclined section to the length
of the rearwardly inclined section may be from 1.33:1 to 3:1.
[0094] In the embodiment of impeller illustrated in FIG. 3 the
auxiliary vanes of the type shown are on the back shroud of an
impeller. In the embodiment of impeller illustrated in FIG. 4 the
auxiliary vanes of the type shown are on the front shroud.
Furthermore, in FIGS. 9 and 12 the auxiliary vanes of the type
shown are on the back shroud. It is to be understood that the
various types of auxiliary vanes shown could be on the back or
front shroud. It is further contemplated that the auxiliary vanes
could be on one of the shrouds with no auxiliary vanes or
conventional auxiliary vanes being on the other shroud. Also one
type of auxiliary vane as described above could be on one of the
shrouds and the same or another type of auxiliary vane could be on
the other shroud. With regard to the expeller described with
reference to FIGS. 7 and 8 any of the types of auxiliary vanes
described above may find use on the expeller.
[0095] Experiments and trials have shown that the auxiliary or
expelling vanes 60, 61 and 89 illustrated in FIGS. 3, 4, 8 and 9
can generate a higher head because of the forwardly inclined
section. This leads to an increase in the pressure in the gap
between the front side liners and front impeller shroud which in
turn reduces the pressure differential between the gap and the rest
of the pumping chamber, resulting in reduced recirculation flow in
the gap and therefore fewer particulates passing through the gap.
This can lead to less wear on the impeller shroud and front side
liner, and increase the functioning life of these components. The
forwardly inclined expelling vanes on the rear shroud of the
impeller have been experimentally observed to reduce the pressure
in the rear seal chamber of the pump. This reduction in seal
chamber pressure is due to the extra head generated by the
forwardly inclined vanes in the gap between the impeller rear
shroud and pump back side liner reducing the pressure differential
between the gap and the main pumping chamber. The reduction in
pressure in the sealing chamber effects a more reliable sealing of
the pump, allowing for reduced gland water flow and lower gland
water pressure. Similar improved performance can be obtained by
implementing forwardly inclined vanes on an expeller, used in an
expeller type pump sealing arrangement. In this case, when paired
with an impeller with traditional radial or rearward sloping
expelling vanes on the back shroud, the expeller with forwardly
inclined vanes can be used to increase the sealing efficiency of
the expeller seal by a margin of up to 20% or greater. In this
case, the forwardly inclined vanes are reducing the pressure
differential between the expeller chamber and the main pumping
chamber. This increases the effective pressure range for which an
expeller seal may be used for any particular pump size.
[0096] 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 "top" and "bottom", "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.
[0097] 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.
[0098] 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.
[0099] 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.
[0100] 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.
[0101] The reference numerals in the following claims do not in any
way limit the scope of the respective claims.
TABLE-US-00002 Table of Parts Pump apparatus 100 Pump 10 Pedestal
112 Outer casing 22 Side casing sections 23, 24 Inlet hole 28
Discharge outlet hole 29 Inner liner 11 Main liner 12 Side liners
(front and back) 14, 30 Bolts 27 Pumping chamber 42 Seal chamber
housing 114 Drive shaft 116 Stuffing box 117 Chamber 118 Impeller
40 Delivery section 32 Passage 33 Outer end 34 Inner end 35
Sidewall section 15 Inner face 37 Inner face 16 Lip 38 Hub 41
Pumping vanes 43 Eye portion 47 Impeller inlet 48 Front shroud 50
Back shroud 51 Outer peripheral edge portion 57 Inner face 55 Outer
face 54 Inner face 53 Outer face 52 Auxiliary vanes 60 Auxiliary
vanes 61 Inner side 63 Outer side 65 Leading side 66 Inner edge 62
Outer edge 64 Trailing side 67 Forwardly inclined section 68 Upper
side 69 Main surface 71 Inclined surface 73 Intermediate region 74
Trailing section 75 Intermediate section 76 Drive shaft 80
Centrifugal seal assembly 82 Expeller 83 Main body 84 Surface 81
Surface 93 Inner section 85 Outer side 86 Outer peripheral edge
portion 91 Seal chamber 87 Passageway 88 Expelling vanes 89 Main
seal apparatus 90 Inner side 163 Outer side 165 Leading side 166
Inner edge 162 Outer edge 164 Trailing side 167 Upper side 169 Main
surface 171 Inclined surface 173
* * * * *