U.S. patent application number 11/644065 was filed with the patent office on 2008-06-26 for centrifugal fluid pump.
This patent application is currently assigned to EMP Advanced Development, LLC. Invention is credited to Nicholas T. Pipkorn.
Application Number | 20080149051 11/644065 |
Document ID | / |
Family ID | 39541093 |
Filed Date | 2008-06-26 |
United States Patent
Application |
20080149051 |
Kind Code |
A1 |
Pipkorn; Nicholas T. |
June 26, 2008 |
Centrifugal fluid pump
Abstract
A centrifugal fluid pump for circulating fluid through an
engine's cooling system includes a body configured to be at least
partially received within a bore in the engine, a shaft having an
impeller rotatably connected to the body, the impeller being
positioned to move fluid through the engine, and a shroud supported
on the body and positioned between the duct and the impeller when
the body is at least partially received within the bore. The shroud
has an opening to permit the movement of fluid to the impeller and
may be configured to engage an inner surface of the bore. The
shroud remains stationary with respect to the bore as the shaft and
the impeller rotate and the shroud and the bore cooperate to
inhibit fluid from passing between the inner surface of the bore
and the shroud to a position that is upstream of the shroud.
Inventors: |
Pipkorn; Nicholas T.;
(Gladstone, MI) |
Correspondence
Address: |
BROOKS KUSHMAN P.C.
1000 TOWN CENTER, TWENTY-SECOND FLOOR
SOUTHFIELD
MI
48075
US
|
Assignee: |
EMP Advanced Development,
LLC
Escanaba
MI
|
Family ID: |
39541093 |
Appl. No.: |
11/644065 |
Filed: |
December 22, 2006 |
Current U.S.
Class: |
123/41.44 |
Current CPC
Class: |
F04D 29/628 20130101;
F04D 29/605 20130101; F04D 29/426 20130101; F01P 5/10 20130101 |
Class at
Publication: |
123/41.44 |
International
Class: |
F01P 5/10 20060101
F01P005/10 |
Claims
1. A centrifugal fluid pump for circulating fluid through an
engine, the engine having a bore to receive the pump and a duct to
direct fluid radially into the pump, the engine further having a
block with a discharge port formed therein to receive fluid
discharged from the pump, the centrifugal fluid pump comprising: a
body configured to be at least partially received within the bore;
a shaft rotatably connected to the body; an impeller fixed to the
shaft and rotatable therewith, the impeller being positioned to
move fluid from the duct to the discharge port when the body is at
least partially received within the bore; and a shroud supported on
the body and positioned between the duct and the impeller when the
body is at least partially received within the bore, the shroud
having an opening to permit movement of fluid from the duct to the
impeller, the shroud being configured to engage an inner surface of
the bore and the shroud remaining stationary with respect to the
bore as the shaft and the impeller rotate, whereby when the body is
at least partially received within the bore, the shroud and the
bore cooperate to inhibit the fluid that is received in the
discharge port from flowing between the inner surface of the bore
and the shroud to a position upstream of the shroud.
2. The centrifugal fluid pump of claim 1 further comprising a seal
arrangement disposed along an outer surface of the shroud to form a
seal between the outer surface of the shroud and the inner surface
of the bore when the body is at least partially received within the
bore to further inhibit the fluid that is received in the discharge
port from flowing between the inner surface of the bore and the
outer surface of the shroud to a position upstream of the
shroud.
3. The centrifugal fluid pump of claim 2 wherein the seal
arrangement includes an o-ring seal.
4. The centrifugal fluid pump of claim 2 wherein the outer surface
of the shroud defines a groove to receive the seal arrangement.
5. The centrifugal fluid pump of claim 1 further comprising a wall
defining a fluid receiving chamber, the wall being connected to an
upstream portion of the shroud and having an inlet opening
positioned to align with the duct when the body is at least
partially received within the bore, the inlet opening permitting
the fluid to flow radially into the fluid receiving chamber from
the duct.
6. The centrifugal fluid pump of claim 5 further comprising a seal
arrangement disposed along an outer surface of the wall, the seal
arrangement forming a seal between the inner surface of the bore
and the outer surface of the wall when the body is at least
partially received within the bore to inhibit the fluid that is
received within the discharge port from flowing between the inner
surface of the bore and the outer surface of the wall to the inlet
opening.
7. The centrifugal fluid pump of claim 6 wherein the seal
arrangement includes an o-ring seal.
8. The centrifugal fluid pump of claim 6 wherein the outer surface
of the wall defines a groove to receive the seal arrangement.
9. The centrifugal fluid pump of claim 1 further comprising: a seal
arrangement disposed along an outer surface of the shroud to form a
seal between the outer surface of the shroud and the inner surface
of the bore when the body is at least partially received within the
bore; and a wall defining a fluid receiving chamber, the wall being
connected to an upstream portion of the shroud, the wall defining
an inlet opening positioned to align with the duct when the body is
at least partially received within the bore, the inlet opening
permitting fluid to flow radially into the fluid receiving chamber
from the duct, the seal arrangement inhibiting the fluid that is
received within the discharge port from flowing between the inner
surface of the bore and the shroud to the inlet opening.
10. The centrifugal fluid pump of claim 1 wherein a portion of the
impeller is disposed in sufficiently close association with an
outer surface of the shroud to inhibit fluid from flowing between
the impeller and the outer surface of the shroud as the impeller
rotates.
11. A centrifugal fluid pump for circulating fluid through an
engine, the engine having a bore to receive the pump and a fluid
path to facilitate circulation of fluid through the engine, the
engine further having a duct connected to the fluid path to direct
fluid radially into the pump, the engine further having a block
with a discharge port formed therein to receive fluid discharged
from the pump, the discharge port being connected to the fluid
path, the centrifugal fluid pump comprising: a housing configured
to be at least partially received within the bore, the housing
having a wall defining a fluid receiving chamber, the wall further
defining an inlet to permit the radial flow of fluid into the fluid
receiving chamber, the inlet aligning with the duct when the
housing is at least partially received within the bore, the housing
further having a shroud contiguous with the wall and disposed
substantially transversely thereto, an inner surface of the shroud
defining a portion of the fluid receiving chamber, the shroud
having an outlet to permit the flow of fluid out of the chamber;
and an impeller assembly supported on the housing and rotatably
connected thereto, the impeller assembly including a bearing
connected to the housing, a shaft rotatably supported on the
bearing and an impeller connected to the shaft, the impeller being
disposed substantially adjacent to an outer surface of the shroud
proximate to the outlet, the impeller being configured to rotate
with respect to the shroud and to draw fluid out of the outlet as
the impeller rotates, the impeller further being disposed proximate
to the discharge port when the housing is at least partially
received within the bore, the impeller being configured to move
fluid into the discharge port as the impeller rotates, the shroud
remaining stationary with respect to the bore as the impeller
rotates, and a periphery of the shroud being configured to engage
an inner surface of the bore such that the periphery of the shroud
and the inner surface of the bore cooperate to inhibit fluid from
flowing upstream from the discharge port into the fluid receiving
chamber.
12. The centrifugal fluid pump of claim 11 further comprising a
seal arrangement disposed along the periphery of the shroud to form
a seal between the periphery of the shroud and the inner surface of
the bore when the housing is at least partially received within the
bore to further inhibit the fluid that is received in the discharge
port from flowing between the inner surface of the bore and the
periphery of the shroud to a position upstream of the shroud.
13. The centrifugal fluid pump of claim 12 wherein the periphery of
the shroud defines a groove to receive the seal arrangement.
14. The centrifugal fluid pump of claim 12 wherein the seal
arrangement includes an o-ring seal.
15. The centrifugal fluid pump of claim 14 wherein the periphery of
the shroud defines a groove to receive the o-ring.
16. The centrifugal fluid pump of claim 11 further comprising a
seal arrangement disposed along an outer surface of the wall to
form a seal between the outer surface of the wall and the inner
surface of the bore when the housing is at least partially received
within the bore to further inhibit the fluid that is received in
the discharge port from flowing between the inner surface of the
bore and the outer surface of the wall to the inlet.
17. The centrifugal fluid pump of claim 16 wherein the outer
surface of the wall defines a groove to receive the seal
arrangement.
18. The centrifugal fluid pump of claim 16 wherein the seal
arrangement includes an o-ring seal.
19. The centrifugal fluid pump of claim 18 wherein the outer
surface of the wall defines a groove to receive the o-ring
seal.
20. The centrifugal fluid pump of claim 11 wherein a portion of the
impeller is disposed in sufficiently close association with the
outer surface of the shroud to inhibit fluid from flowing between
the impeller and the outer surface of the shroud as the impeller
rotates.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a centrifugal fluid pump
for circulating fluid through an engine.
[0003] 2. Background Art
[0004] Internal combustion engines use coolant systems to prevent
overheating. A pump may be used to circulate fluid through an
internal combustion engine's cooling system to control the
operational temperature of the engine. A centrifugal fluid pump is
one type of pump that can be used to circulate fluid through an
engine's cooling system. A centrifugal fluid pump is one that
discharges fluid radially from the impeller. Engines configured to
receive a centrifugal fluid pump frequently include a discharge
port, for example, a volute, formed in the engine block to receive
the radially discharged fluid and to direct such fluid along a
coolant path through the engine. The path leads back to the pump
and the cycle begins again. Some engines have a bore defined in the
engine block disposed along the coolant path to receive the fluid
pump. This allows the fluid pump to be inserted into the coolant
path.
[0005] Some manufacturers make engines that are configured with a
coolant path that directs fluid radially into a fluid pump. In such
an arrangement, fluid flows radially into the centrifugal fluid
pump from the engine's coolant path to a location that is upstream
of an impeller. Fluid is then moved downstream into the discharge
port by the impeller. One problem encountered with this type of
pump is the tendency of some of the fluid to flow from an area in
the discharge port that is down stream of the impeller directly to
an area in the pump that is upstream of the impeller, thereby
bypassing the coolant path. This recirculation reduces the
efficiency of the pump because fluid never goes through the
engine.
[0006] Some manufacturers of centrifugal fluid pumps have attempted
to counter this problem by attaching a shroud to the impeller shaft
that rotates with the impeller in an attempt to create a barrier
between the upstream and the downstream areas of the centrifugal
fluid pump. Such rotating shrouds, however, still permit the flow
of some coolant to an upstream location after being discharged into
the discharge port because of a gap between a periphery of the
shroud and the inner surface of the bore that is needed to permit
the shroud to rotate. This and other problems are addressed by the
present invention.
SUMMARY OF THE INVENTION
[0007] In at least one embodiment, the present invention may
include a centrifugal fluid pump for circulating fluids through an
engine having a bore to receive the pump and a duct to direct fluid
radially into the pump. The engine further has a block having a
discharge port formed therein to receive fluid discharged from the
pump. In such an arrangement, the centrifugal fluid pump comprises
a body that is configured to be at least partially received within
the bore, a shaft that is rotatably connected to the body, an
impeller that is fixed to the shaft and rotatable therewith, the
impeller being positioned to move fluid from the duct to the
discharge port when the body is at least partially received within
the bore, and a shroud supported on the body and positioned between
the duct and the impeller when the body is at least partially
received within the bore. The shroud may have an opening to permit
the movement of the fluid from the duct to the impeller, and the
shroud may be configured to engage an inner surface of the bore.
The shroud remains stationary with respect to the bore as the shaft
and the impeller rotate. In this arrangement, when the body is at
least partially received within the bore, the shroud and the bore
cooperate to inhibit fluid that is received in the discharge port
from flowing between the inner surface of the bore and the shroud
to a position upstream of the shroud.
[0008] There are many ways to implement the first embodiment. In at
least one implementation, the centrifugal fluid pump further
includes a seal arrangement disposed along an outer surface of the
shroud to form a seal between the outer surface of the shroud and
the inner surface of the bore when the body is at least partially
received within the bore. This further inhibits the fluid that is
received in the discharge port from flowing between the inner
surface of the bore and the outer surface of the shroud to a
position upstream of the shroud. In at least one variation of this
implementation, the seal arrangement includes an O-ring seal. In at
least another variation of this implementation, an outer surface of
the shroud defines a groove to receive the seal arrangement.
[0009] In at least another implementation of the first embodiment,
the centrifugal fluid pump further comprises a wall defining a
fluid receiving chamber. The wall may be connected to an upstream
portion of the shroud and may have an inlet opening that is
positioned to align with the duct when the body is at least
partially received within the bore. In this implementation, the
inlet opening permits the fluid to flow radially into the fluid
receiving chamber from the duct. In at least one variation of this
implementation, the centrifugal fluid pump further comprises a seal
arrangement disposed along an outer surface of the wall. The seal
arrangement may form a seal between the inner surface of the bore
and the outer surface of the wall when the body is at least
partially received within the bore. In this arrangement, the seal
inhibits the fluid that is received within the discharge port from
flowing between the inner surface of the bore and the outer surface
of the wall to the inlet opening. In a further variation of this
implementation, the seal arrangement may include an O-ring seal. In
a further variation of this implementation, the outer surface of
the wall may define a groove to receive the seal arrangement.
[0010] In at least another implementation of the first embodiment,
the centrifugal fluid pump may further comprise a seal arrangement
that is disposed along an outer surface of the shroud to form a
seal between the outer surface of the shroud and the inner surface
of the bore when the housing is at least partially received within
the bore. The centrifugal fluid pump may further comprise a wall
defining a fluid receiving chamber. The wall may be connected to an
upstream portion of the shroud and the wall may define an inlet
opening that is positioned to align with the duct when the body is
at least partially received within the bore. The inlet opening
permits fluid to flow radially into the fluid receiving chamber
from the duct. In this implementation, the seal arrangement
inhibits the fluid that is received within the discharge port from
flowing between the inner surface of the bore and the shroud to the
inlet opening.
[0011] In at least another implementation of the first embodiment,
a portion of the impeller is disposed in sufficiently close
association with an outer surface of the shroud so as to inhibit
fluid from flowing between the impeller and the outer surface of
the shroud as the impeller rotates.
[0012] In at least a second embodiment, a centrifugal fluid pump
for circulating fluid through an engine is provided. The engine has
a bore to receive the pump and a fluid path to facilitate
circulation of fluid through the engine. The engine further has a
duct that is connected to the fluid path to direct fluid radially
into the pump. The engine further has a block with a discharge port
formed therein to receive the fluid that is discharged from the
pump, the discharge port being connected to the fluid path. In this
arrangement, the centrifugal fluid pump includes a housing that is
configured to be at least partially received within the bore. The
housing has a wall that defines a fluid receiving chamber. The wall
further defines an inlet to permit the radial flow of fluid into
the fluid receiving chamber, the inlet aligning with the duct when
the housing is at least partially received within the bore. The
housing further has a shroud that is contiguous with the wall and
disposed substantially transversely thereto. An inner surface of
the shroud may define a portion of the fluid receiving chamber. The
shroud includes an outlet to permit the flow of fluid out of the
chamber. The centrifugal fluid pump further comprises an impeller
assembly that is supported on the housing and rotatably connected
thereto. The impeller assembly includes a bearing that is connected
to the housing, a shaft that is rotatably supported on the bearing,
and an impeller that is connected to the shaft, the impeller being
disposed substantially adjacent to an outer surface of the shroud
proximate to the outlet. The impeller may be configured to rotate
with respect to the shroud and to draw fluid out of the outlet as
the impeller rotates. Further, the impeller may be disposed
proximate to the discharge port when the housing is at least
partially received within the bore, the impeller being configured
to move fluid into the discharge port as the impeller rotates. In
at least this embodiment, the shroud remains stationary with
respect to the bore as the impeller rotates and a periphery of the
shroud may be configured to engage an inner surface of the bore
such that the periphery of the shroud and the inner surface of the
bore cooperate to inhibit fluid from flowing upstream from the
discharge port into the fluid receiving chamber.
[0013] There are many ways to implement the second embodiment. In
least one implementation, the centrifugal fluid pump of the second
embodiment further comprises a seal arrangement that is disposed
along the periphery of the shroud to form a seal between the
periphery of the shroud and the inner surface of the bore when the
housing is at least partially received within the bore to further
inhibit the fluid that is received in the discharge port from
flowing between the inner surface of the bore and the periphery of
the shroud to a position that is upstream of the shroud. In at
least one variation of this implementation, the periphery of the
shroud defines a groove to receive the seal arrangement. In at
least another variation of this implementation, the seal
arrangement includes an O-ring seal. In still another variation of
this implementation, the periphery of the shroud defines a groove
to receive the O-ring.
[0014] In another implementation of the second embodiment, the seal
arrangement may be disposed along an outer surface of the wall to
form a seal between the outer surface of the wall and the inner
surface of the bore when the housing is at least partially received
within the bore so as to further inhibit the fluid that is received
in the discharge port from flowing between the inner surface of the
bore and the outer surface of the wall to the inlet. In at least
one variation of this implementation, the outer surface of the wall
defines a groove to receive the seal arrangement. In at least
another variation of this implementation, the seal arrangement
includes an O-ring seal. In still another variation of this
implementation, the outer surface of the wall defines a groove to
receive the O-ring seal.
[0015] In at least another implementation of the second embodiment,
a portion of the impeller is disposed in sufficiently close
association with the outer surface of the shroud to inhibit fluid
from flowing between the impeller and the outer surface of the
shroud as the impeller rotates.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is an exploded view of a centrifugal fluid pump and
an engine block;
[0017] FIG. 2 is a cutaway perspective view of the centrifugal
fluid pump received within the engine block;
[0018] FIG. 3 is a fragmentary cross-sectional view of a portion of
the engine block taken along the line 3-3 of FIG. 2;
[0019] FIG. 4 is a fragmentary cross-sectional view of a portion of
the engine block and an embodiment of the centrifugal fluid pump
received within a bore of the engine block taken along the line 3-3
of FIG. 2;
[0020] FIG. 5 is a fragmentary cross-sectional view of FIG. 4
depicting a second embodiment of the centrifugal fluid pump;
and
[0021] FIG. 6 is a fragmentary cross-sectional view of FIG. 4
depicting a third embodiment of the centrifugal fluid pump.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0022] A centrifugal fluid pump 10 is shown in FIG. 1. Centrifugal
fluid pump 10 is configured to be received within an engine 12,
also shown in FIG. 1. Engine 12 includes a coolant path 14
configured to contain and circulate fluid through the engine and a
heat exchanger (not shown) to maintain the engine at a desired
temperature during engine operation. Engine 12 further includes a
bore 16 that is configured to at least partially receive the
centrifugal fluid pump 10. The bore 16 is disposed along coolant
path 14. Coolant path 14 includes a duct 18 for directing coolant
radially into the bore 16.
[0023] Centrifugal fluid pump 10 includes a body or housing 20
having a wall 22. In the embodiment illustrated in FIG. 1, the wall
22 defines a fluid receiving chamber 24 and an inlet 26 defined in
the wall 22 to permit fluid to enter the fluid receiving chamber
24. Centrifugal fluid pump 10 is configured to be at least
partially received within bore 16. When centrifugal fluid pump 10
is at least partially received within bore 16, inlet 26 aligns with
duct 18 to allow fluid to flow radially from the coolant path 14
into the fluid receiving chamber 24.
[0024] In the illustrated embodiment, centrifugal fluid pump 10
includes a shaft 28 that is rotatably connected at one end to the
body 20. At an opposite end, impeller 30 is mounted to shaft 28 and
configured to rotate together with shaft 28 with respect to body
20. The rotation of impeller 30 causes fluid to move from the fluid
receiving chamber 24 to the impeller 30. As the fluid engages
impeller 30, it is discharged radially from impeller 30.
[0025] When impeller 30 is at least partially received within bore
16, impeller 30 is disposed proximate to discharge port 32.
Discharge port 32 is configured to receive the fluid that is
radially discharged from impeller 30 and to redirect it along
coolant path 14. In the embodiment illustrated in FIGS. 1-6,
discharge port 32 is a volute which has generally spiral
configuration and which is adapted to convert the radial motion of
fluid discharged from impeller 30 to linear motion. Discharge ports
having other configurations may also be utilized to receive the
fluid discharged from impeller 30.
[0026] As shown in FIG. 2, when centrifugal fluid pump 10 is at
least partially received within bore 16, inlet 26 aligns with duct
18 to radially receive fluid into the fluid receiving chamber 24.
Impeller 30 is positioned at least partially within the discharge
port 32. Arranged in this manner, the coolant path 14, including
the duct 18 and the discharge port 32 together with the centrifugal
fluid pump 10, form a substantially closed path for the circulation
of coolant through engine 12.
[0027] FIG. 3 is a fragmentary cross-sectional view of a portion of
engine 12. The portion depicted is configured to receive a
centrifugal fluid pump 10 within bore 16. As illustrated, duct 18
opens into bore 16 to allow for the radial introduction of fluid. A
rear portion of bore 16 opens to discharge port 32 to receive fluid
discharged from centrifugal fluid pump 10. Engine 12 includes holes
34 to permit centrifugal fluid pump 10 to be fastened to engine 12.
The bore 16 includes an internal surface 36 that is configured to
receive the centrifugal fluid pump 10 when centrifugal fluid pump
10 is inserted into the bore 16.
[0028] FIG. 4 depicts a first embodiment of centrifugal fluid pump
10 at least partially received within bore 16. As illustrated,
centrifugal fluid pump 10 includes a body or housing 38, a bearing
40 connected to the body 38 and an impeller shaft 42 rotatably
connected to the body 38 by bearing 40. A pulley hub 44 is
connected to impeller shaft 42 and is configured for connection to
a serpentine belt which may wrap around a portion of pulley hub 44
and which may cause pulley hub 44 to rotate as the serpentine belt
moves. In other engines, an apparatus other than a serpentine belt
may be used to rotate pulley hub 44. In other embodiments of the
present invention, structures other than pulley hub 44 may be used
to impart rotation to impeller shaft 42.
[0029] As illustrated, centrifugal fluid pump 10 may further
include a flange 46. Flange 46 engages an outer surface of engine
12 to control the depth of insertion of the centrifugal fluid pump
10 into the bore 16. Flange 46 includes holes 48 which align with
holes 34 when centrifugal fluid pump 10 is at least partially
received within bore 16. Bolt 50 passes through hole 48 and is
received in hole 34 and, through threaded engagement with an
interior surface of hole 34, secures centrifugal fluid pump 10 to
engine 12. In other embodiments, screws, other threaded fasteners
or any other fastener effective to secure centrifugal fluid pump 10
to engine 12 may be used.
[0030] Body 38 further includes a body seal groove 52 to receive a
body seal 54. Body seal 54 serves to fluidly seal the body 38
against an inner surface of bore 16 to prevent fluid from leaving
the coolant path and leaking to an area outside of engine 12. In
other embodiments, body seal 54 may be disposed on body 38 so as to
contact engine 12 along an outer surface of engine 12 as opposed to
an inner surface of bore 16. In at least one embodiment, body seal
54 may be a rubber o-ring. In other embodiments, body seal 54 may
be any type of seal effective to prevent fluid from leaving the
coolant path and leaking to an area outside of engine 12.
[0031] As illustrated in FIG. 4, centrifugal fluid pump 10 includes
a wall 22 connected to the body 38. The wall 22 defines the fluid
receiving chamber 24. Inlet 26 is defined in wall 22 and, as
illustrated in FIG. 4, aligned with duct 18 when centrifugal fluid
pump 10 is at least partially received within bore 16. An outer
surface of wall 22 engages an inner surface of bore 16 when
centrifugal fluid pump 10 is at least partially received within
bore 16. In some embodiments, such engagement may be in the form of
an interference fit. In other embodiments, such engagement may take
the form of a close association between the two surfaces, meaning
that the two surfaces are disposed very close to one another. In at
least some embodiments, once centrifugal fluid pump 10 is at least
partially received within bore 16, and once centrifugal fluid pump
10 is fastened to engine 12, wall 22 remains stationary with
respect to the inner surface of bore 16. In other embodiments,
centrifugal fluid pump 10 may have neither wall 22 nor fluid
receiving chamber 24.
[0032] The centrifugal fluid pump 10 illustrated in FIG. 4 further
includes a shroud 60 connected to wall 22. Through this connection
to wall 22, shroud 60 remains stationary with respect to body 38.
In embodiments lacking a wall 22, shroud 60 may be connected to
body 38 in a non-rotational fashion through other means such as
posts, bands, beams, struts, braces, or any other member effective
to attach shroud 60 to body 38 so that shroud 60 does not rotate.
In the illustrated embodiment, an inner surface of shroud 60
defines a portion of fluid receiving chamber 24. In other
embodiments, the shroud 60 may be separate from the structure
defining fluid receiving chamber 24. Shroud 60 includes an opening
or outlet 62 to permit fluid to flow out of the fluid receiving
chamber 24. As illustrated, impeller shaft 42 extends through the
fluid receiving chamber 24, protrudes through opening 62 and is
disposed within the discharge port 32.
[0033] A periphery 64 of shroud 60 is illustrated in close
association with the inner surface of bore 16. In some embodiments,
the periphery 64 may be in contact with the inner surface of the
bore at one or more locations around periphery 64. In other
embodiments, the entire periphery 64 may be in contact with an
inner surface of the bore 16. In still other embodiments, portions
of the periphery 64 may provide an interference fit with the inner
surface of the bore 16. In still other embodiments, the entire
periphery 64 may provide an interference fit with the inner surface
of the bore 16.
[0034] Impeller 66 is connected to impeller shaft 42 and is
configured to rotate together with impeller shaft 42. Impeller 66
includes vanes 68 which, in the embodiment illustrated in FIG. 4,
are disposed in close association with an outer surface of shroud
60. In some embodiments, vanes 68 may be disposed so as to provide
a sliding contact with the outer surface of shroud 60.
[0035] When a serpentine belt or other source of rotation is
applied to pulley hub 44, impeller shaft 42 rotates with respect to
body 38 causing impeller 66 to rotate. When impeller 66 rotates, it
pushes fluid radially away from impeller 66 into discharge port 32.
Discharge port 32 directs the moving fluid into the coolant path 14
which then circulates the fluid through engine 12 to duct 18 where
the fluid passes through inlet 26 and enters fluid receiving
chamber 24. From the fluid receiving chamber 24, the fluid is moved
through opening 62 back to impeller 66. The path of the fluid is
indicated in FIG. 4 with arrows showing the direction of fluid
travel.
[0036] The efficiency with which centrifugal fluid pump 10 moves
fluid through engine 12 could be adversely impacted if fluid
received within the discharge port 32 were to leak back to inlet 26
instead of entering the coolant path 14. By providing a shroud 60
that remains stationary, a very close association between the
periphery 64 and an inner surface of the bore 16 can be provided so
as to inhibit the fluid from leaking between the periphery 64 and
an inner surface of the bore 16 back to inlet 26.
[0037] The efficiency of centrifugal pump 10 can be further
improved by disposing vanes 68 in close association with an outer
surface of shroud 60. A close association can inhibit fluid from
flowing between these components. Fluid that flows between vanes 68
and an outer surface of shroud 60 does not enter the coolant path
14, but instead recirculates through impeller 66. The narrower the
gap is between vanes 68 and the outer surface of shroud 60, the
less fluid will recirculate, and the greater will be the efficiency
of the centrifugal fluid pump 10.
[0038] To further improve the efficiency of the centrifugal fluid
pump 10, an additional seal can be used. FIG. 5 illustrates one
embodiment of a centrifugal fluid pump 10 utilizing an additional
seal to further inhibit fluid from leaking between the periphery 64
of shroud 60 and an inner surface of bore 16. In the illustrated
embodiment, an O-ring seal 70 is received within O-ring seal groove
72, both of which are disposed along the periphery 64 of the shroud
60. As illustrated, O-ring 70 provides an interference fit against
an inner surface of the bore 60. Disposed around the entire
periphery 64 of shroud 60, O-ring seal 70 inhibits fluid from
leaking from the discharge port 32 to inlet 26. Seals other than
O-ring seals may also be utilized. In still other embodiments, the
seal arrangement may be disposed elsewhere on the centrifugal fluid
pump 10. For instance, as illustrated in FIG. 6, an O-ring seal 74
is disposed within an O-ring seal groove 76 that is disposed along
an outer surface of wall 22. In the arrangement illustrated in FIG.
6, any fluid that leaks between periphery 64 of shroud 60 and an
inner surface of bore 16 will be inhibited from reaching inlet 26
by O-ring seal 74.
[0039] While embodiments of the invention have been illustrated and
described, it is not intended that these embodiments illustrate and
describe all possible forms of the invention. Rather, the words
used in the specification are words of description rather than
limitation, and it is understood that various changes may be made
without departing from the spirit and scope of the invention.
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