U.S. patent application number 13/655361 was filed with the patent office on 2014-01-30 for centrifugal pump.
Invention is credited to Roxann M. Bittner, Robert S. McAlpine, David R. Staley.
Application Number | 20140030086 13/655361 |
Document ID | / |
Family ID | 49995064 |
Filed Date | 2014-01-30 |
United States Patent
Application |
20140030086 |
Kind Code |
A1 |
Staley; David R. ; et
al. |
January 30, 2014 |
CENTRIFUGAL PUMP
Abstract
Embodiments of the disclosure include a centrifugal pump
assembly including a pump housing defining a cavity and an impeller
disposed within the cavity, the impeller being affixed to a shaft.
The pump housing includes an inner surface having a geometric
pattern configured in increase a turbulence of a fluid flow over
the inner surface. The impeller includes one or more blades and a
shroud. The inner surface of the pump housing and the shroud of the
impeller define a leakage path.
Inventors: |
Staley; David R.; (Flushing,
MI) ; McAlpine; Robert S.; (Lake Orion, MI) ;
Bittner; Roxann M.; (Rochester Hills, MI) |
Family ID: |
49995064 |
Appl. No.: |
13/655361 |
Filed: |
October 18, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61676024 |
Jul 26, 2012 |
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Current U.S.
Class: |
415/208.1 |
Current CPC
Class: |
F04D 29/167 20130101;
F04D 29/4246 20130101; F04D 29/406 20130101 |
Class at
Publication: |
415/208.1 |
International
Class: |
F04D 29/40 20060101
F04D029/40 |
Claims
1. An centrifugal pump assembly comprising: a pump housing defining
a cavity, wherein the pump housing comprises an interior surface
having a geometric pattern configured in increase a turbulence of a
fluid flow over the inner surface; an impeller disposed in the
cavity, wherein the impeller comprises one or more blades and a
shroud; and a shaft affixed to the impeller; wherein the interior
surface of the pump housing and the shroud of the impeller define a
leakage path.
2. The centrifugal pump assembly of claim 1, wherein the geometric
pattern includes a series of concentric ribs.
3. The centrifugal pump assembly of claim 1, wherein the geometric
pattern includes a series of concentric labyrinth rings.
4. The centrifugal pump assembly of claim 1, wherein the geometric
pattern includes a plurality of protrusions that project towards
the shroud.
5. The centrifugal pump assembly of claim 4, wherein the plurality
of protrusions have a hemi-spherical shape, a pyramid shape, or a
conical shape.
6. The centrifugal pump assembly of claim 1, wherein the geometric
pattern is configured to maximize a turbulence of a fluid flow in
the leakage path, wherein an increase in the turbulence of the
fluid flow in the leakage path results in a reduction of a volume
of the fluid flow.
7. An centrifugal pump assembly comprising: a pump housing defining
a cavity, wherein the pump housing comprises an interior surface;
an impeller disposed in the cavity, wherein the impeller comprises
one or more blades and a shroud; a shaft affixed to the impeller;
wherein the interior surface of the pump housing and an exterior
surface of the shroud of the impeller define a leakage path; and
wherein at least one of the interior surface of the pump housing
and the exterior surface of the shroud include a geometric pattern
configured to maximize a turbulence of a fluid flow in the leakage
path, wherein an increase in the turbulence of the fluid flow in
the leakage path results in a reduction of a volume of the fluid
flow.
8. The centrifugal pump assembly of claim 7, wherein the geometric
pattern includes a series of concentric ribs.
9. The centrifugal pump assembly of claim 7, wherein the geometric
pattern includes a series of concentric labyrinth rings.
10. The centrifugal pump assembly of claim 7, wherein the geometric
pattern includes a plurality of protrusions that project towards
the shroud.
11. The centrifugal pump assembly of claim 7, wherein the pump
housing is formed by casting aluminum and the geometric pattern is
formed during the casting process.
12. The centrifugal pump assembly of claim 7, wherein the pump
housing is formed by casting aluminum and the geometric pattern is
formed by machining the pump housing.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims priority to U.S. Provisional
Patent Application Ser. No. 61/676,024 filed on Jul. 26, 2012 which
is hereby incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] Exemplary embodiments of the present invention relate to a
pump assembly and, more particularly, to a centrifugal pump
assembly with increased efficiency.
BACKGROUND
[0003] Shaft driven centrifugal pumps are often used for cooling of
automotive engines. Centrifugal pumps operate by having water, or
other fluid, directed axially into the pump and exit radially into
one or more volutes. The shaft is typically mechanically driven,
directly or indirectly by the engine crankshaft, and therefore
rotates at some speed proportional to engine speed. Generally,
centrifugal pumps include an impeller that rotates in a pocket. The
impeller includes a shroud that is attached to the edge of the
impeller vanes to help route the flow of fluid from a low pressure
region at the pump's center to the high pressure region at the
pump's outer perimeter.
[0004] Typically centrifugal pumps include a pump cavity that is
located in close proximity to the shroud and a resulting leak path
between the pump cavity and the shroud. The hydraulic efficiency of
the pump is substantially affected by the clearance between the
shroud and the pump cavity due to the leakage flow at this
interface. Accordingly, the clearance between the shroud and the
pump cavity is usually minimized. However, manufacturing tolerances
place limits on the extent by which the clearance can be
minimized.
[0005] In general, the design of the pump affects the efficiency of
the pump. An increase in pump efficiency means less power is
consumed in driving the pump, and can result in improved fuel
economy. In addition, less than ideal fluid flow in the pump can
result in flow separation in the flow field, which reduces pump
capacity and may cause unwanted pump noise due to cavitation.
SUMMARY OF THE INVENTION
[0006] In an exemplary embodiment, a centrifugal pump assembly
includes a pump housing defining a cavity. The pump housing
includes an interior surface having a geometric pattern configured
to increase turbulence of the fluid flow over the interior surface.
The centrifugal pump assembly also includes an impeller disposed in
the cavity, the impeller including one or more blades and a shroud.
The centrifugal pump assembly further includes a shaft affixed to
the impeller. The interior surface of the pump housing and the
shroud of the impeller define a leakage path.
[0007] In another exemplary embodiment, a centrifugal pump assembly
includes a pump housing defining a cavity, wherein the pump housing
includes an interior surface. The centrifugal pump assembly also
includes an impeller having one or more blades and a shroud
disposed in the cavity. The centrifugal pump assembly also includes
a shaft affixed to the impeller. The interior surface of the pump
housing and an exterior surface of the shroud of the impeller
define a leakage path. At least one of the interior surface of the
pump housing and the exterior surface of the shroud include a
geometric pattern configured to maximize a turbulence of a fluid
flow in the leakage path.
[0008] The above features and advantages, and other features and
advantages of the present invention are readily apparent from the
following detailed description of the invention when taken in
connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Other objects, features, advantages and details appear, by
way of example only, in the following detailed description of the
embodiments, the detailed description referring to the drawings in
which:
[0010] FIG. 1 is a cross sectional side view of a centrifugal pump
assembly;
[0011] FIG. 2 is a plan view of a pump housing of the centrifugal
pump assembly of FIG. 1; and
[0012] FIG. 3 a cross sectional side view of a centrifugal pump
assembly in accordance with an exemplary embodiment;
[0013] FIG. 4 is a perspective view of an pump housing in
accordance with an exemplary embodiment;
[0014] FIG. 5 is a plan view of a pump housing in accordance with
another exemplary embodiment; and
[0015] FIG. 6 is a plan view of a pump housing in accordance with a
further exemplary embodiment.
DESCRIPTION OF THE EMBODIMENTS
[0016] The following description is merely exemplary in nature and
is not intended to limit the present disclosure, application or
uses. It should be understood that throughout the drawings,
corresponding reference numerals indicate like or corresponding
parts and features.
[0017] Referring now to FIG. 1, a centrifugal pump assembly 100 is
shown. The centrifugal pump assembly 100 includes a pump housing
110, which includes a cavity 112 and one or more volutes 114. In
addition, the centrifugal pump assembly 100 includes a rotatable
shaft 104 and a seal 106 that prevents fluid from passing out of
the cavity 112 past the shaft 104. The centrifugal pump assembly
100 further includes an impeller 120 disposed inside of the cavity
112 such that the shaft 104 extends through an aperture 122 of the
impeller 120. The impeller 120 is fit onto the shaft 104 for
rotation with the shaft 104. The impeller 120 includes blades 124
and a shroud 126. The shroud 126 is affixed to the impeller 120 and
is configured to rotate with the impeller 120. The shroud 126 of
the impeller is disposed adjacent to an interior surface 116 of the
cavity 112. The separation of the shroud 126 and the interior
surface 116 of the cavity 112 define a leakage path 140. The
hydraulic efficiency of the pump is substantially affected by the
fluid flow in the leakage path 140. Accordingly, the clearance
between the shroud 126 and the interior surface 116 of the cavity
112 has typically been minimized to minimize the fluid flow through
the leakage path 140. Typically, as best illustrated by FIG. 2, the
interior surface 116 has a generally smooth surface.
[0018] In exemplary embodiments, the interior surface 116 of the
cavity 112 includes a geometric pattern that is configured to
increase the turbulence of a fluid flow in the leakage path 140. By
increasing the turbulence of the fluid flow through the leakage
path 140, the volume of flow through the leakage path can be
reduced and the volumetric efficiency of the pump 100 can be
increased. In exemplary embodiments, the geometric pattern added to
the interior surface 116 of the cavity does not result in a
decrease in a required minimum physical separation between the
shroud and the interior surface of the cavity. In exemplary
embodiments, a wide variety of different geometries can be used to
increase the turbulence of a fluid flow in the leakage path.
[0019] Referring now to FIG. 3, a cross-section of a centrifugal
pump assembly 200 in accordance with an exemplary embodiment is
shown. The centrifugal pump assembly 200 is a shaft driven,
centrifugal automotive water pump, but the invention as claimed is
not limited to such. The centrifugal pump assembly 200 includes a
pump housing 210, which includes a cavity 212 and one or more
volutes (not shown). In addition, the centrifugal pump assembly 200
includes a rotatable shaft 204 and a seal 206 that prevents fluid
from passing out of the cavity 212 past the shaft 204. The
centrifugal pump assembly 200 further includes an impeller 220
disposed inside of the cavity 212 such that the shaft 204 extends
through an aperture 222 of the impeller 220. The impeller 220 is
fit onto the shaft 204 for rotation with the shaft 204. The
impeller 220 includes blades and a shroud 226. The shroud 226 is
affixed to the impeller 220 and is configured to rotate with the
impeller 220. The shroud 226 of the impeller 220 is disposed
adjacent to an interior surface 216 of the cavity 212. The
separation of the shroud 226 and the interior surface 216 of the
cavity 212 define a leakage path 240.
[0020] In exemplary embodiments, the interior surface 216 of the
cavity 212 includes a geometric pattern 230. In exemplary
embodiments, the geometric pattern 230 may include a wide variety
of different geometries that are configured to increase the
turbulence of a fluid flow in the leakage path 240. By increasing
the turbulence of a fluid flow in the leakage path 240 the volume
of flow through the leakage path can be reduced and the hydraulic
efficiency of the pump can be increased. In an alternative
exemplary embodiment, the geometric pattern configured to increase
the turbulence of a fluid flow in the leakage path 240 may be
disposed on an exterior surface of the shroud 226 adjacent to the
interior surface 216 of the cavity 212. In yet another exemplary
embodiment, geometric patterns configured to increase the
turbulence of a fluid flow in the leakage path 240 may be disposed
on both the exterior surface of the shroud 226 and the interior
surface 216 of the cavity 212. In exemplary embodiments, the
geometric pattern of the interior surface 216 of the cavity 212 and
the shroud 226 form a labyrinth seal. In general, labyrinth seals
provide non-contact sealing by limiting the passage of fluid
through chambers by the formation of controlled fluid vortices that
result from flow over sharp edge conditions or through a torturous
path.
[0021] Referring now to FIG. 4, a pump housing 310 in accordance
with an exemplary embodiment is shown. As illustrated, the interior
surface 316 includes a geometric pattern 330 configured to increase
the turbulence of a fluid flow across the interior surface 316. In
exemplary embodiments the geometric pattern 330 may include a
series of sharp edges in the form of concentric ribs 332 that
project upwards toward the shroud of the impeller. In exemplary
embodiments, the sharp edges of the ribs 332 cause the leakage flow
to locally separate from each corner which limits the effective
flow cross-sectional area and thus reduces the extent of leakage
flow.
[0022] Referring now to FIG. 5, a pump housing 410 in accordance
with another exemplary embodiment is shown. As illustrated, the
interior surface 416 includes a geometric pattern 430 configured to
increase the turbulence of a fluid flow across the interior surface
416. In exemplary embodiments the geometric pattern 430 may include
a series of concentric labyrinth rings 432 that are attached to
form a screw that project upwards toward the shroud of the
impeller. In exemplary embodiments, the top edges of the rings 432
cause the leakage flow to locally separate from each corner which
increases limits the effective flow cross-sectional area and thus
reduces the extent of leakage flow.
[0023] Referring now to FIG. 6, a pump housing 510 in accordance
with a further exemplary embodiment is shown. As illustrated, the
interior surface 516 includes a geometric pattern 530 configured to
increase the turbulence of a fluid flow across the interior surface
516. In exemplary embodiments the geometric pattern 530 may include
a plurality of protrusions 532 that project upwards toward the
shroud of the impeller. In exemplary embodiments, the protrusion
532 may have a stepped shape as illustrated or may have a smooth
surface. In exemplary embodiments, the protrusions 532 cause the
leakage flow to be locally redirected at each protrusion 532 which
increases the length of flow path and resulting pressure drop and
thus reduces the extent of leakage flow. In exemplary embodiment,
the plurality of protrusions 532 may be arranged in a wide variety
of configurations and each of the plurality of protrusions 532 may
have a wide variety of shapes. For example, the protrusions 532 may
have a hemi-spherical shape, a pyramid shape, a conical shape, or
any other suitable shape. In exemplary embodiments the arrangement
and shape of the plurality of protrusions 532 on the interior
surface 516 may be optimized to maximize the turbulence induced by
the protrusions 532 on a fluid flow over the interior surface
516.
[0024] It will be appreciated by those of ordinary skill in the art
that the geometries disposed on the interior surface of the cavity
illustrated in FIGS. 4-6 are provided for exemplary purposed only
and that scope of this disclosure is not intended to be limited to
the geometries illustrated.
[0025] In exemplary embodiments, by increasing the turbulence of a
fluid flow in the leakage path of the centrifugal pump assembly the
efficiency of the centrifugal pump can be increased. For example,
by reducing the fluid flow in the leakage path the amount of fluid
flow through the volutes can be increased without requiring
additional power to operate the pump. While the reduction of
leakage flow may improve the pump's volumetric efficiency, it also
has the potential of adversely affecting its mechanical efficiency.
However, it has been found that the improvement in volumetric
efficiency is greater that the loss in mechanical efficiency and
thus the overall hydraulic efficiency may be improved by 1-2%.
[0026] In exemplary embodiments, the pump housing may be cast
aluminum and the geometric pattern may be formed either during the
casting process or may be machined into the interior surface of the
pump housing after the pump housing is cast. In other exemplary
embodiments, the pump housing may be made of a composite material
and the geometric pattern is formed on the interior surface of the
pump housing during the fabrication process.
[0027] While the invention has been described with reference to
exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiments disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the present
application.
* * * * *