U.S. patent application number 16/814041 was filed with the patent office on 2020-09-17 for centrifugal pump.
This patent application is currently assigned to AISAN KOGYO KABUSHIKI KAISHA. The applicant listed for this patent is AISAN KOGYO KABUSHIKI KAISHA. Invention is credited to Yoshihiko HONDA, Naoki SHIRAI, Hironori SUZUKI.
Application Number | 20200291956 16/814041 |
Document ID | / |
Family ID | 1000004702963 |
Filed Date | 2020-09-17 |
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United States Patent
Application |
20200291956 |
Kind Code |
A1 |
HONDA; Yoshihiko ; et
al. |
September 17, 2020 |
Centrifugal Pump
Abstract
A centrifugal pump includes an impeller and a housing defining a
pump chamber that houses the impeller therein. The housing includes
an inlet passage in fluid communication with the pump chamber and
an outside of the housing. The inlet passage includes a connection
passage part having a cylindrical shape extending from the pump
chamber and a main passage part having a cylindrical shape
connected to the connection passage part, so as to form a bent
shape. A central axis of the main passage part is parallel to a
reference plane that includes a central axis of the connection
passage part. A flow direction of a fluid parallel the central axis
of the main passage part is partly the same as the rotational
direction of the impeller in a plan view along an axis of the
impeller.
Inventors: |
HONDA; Yoshihiko; (Obu-shi,
JP) ; SUZUKI; Hironori; (Obu-shi, JP) ;
SHIRAI; Naoki; (Toyohashi-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AISAN KOGYO KABUSHIKI KAISHA |
Obu-shi |
|
JP |
|
|
Assignee: |
AISAN KOGYO KABUSHIKI
KAISHA
Obu-shi
JP
|
Family ID: |
1000004702963 |
Appl. No.: |
16/814041 |
Filed: |
March 10, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 29/42 20130101;
F04D 17/10 20130101 |
International
Class: |
F04D 29/42 20060101
F04D029/42; F04D 17/10 20060101 F04D017/10 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 12, 2019 |
JP |
2019-044517 |
Claims
1. A centrifugal pump, comprising: an impeller configured to rotate
about a rotational axis in a rotational direction; and a housing
defining a pump chamber within which the impeller is disposed,
wherein the housing includes an inlet passage and an outlet
passage, wherein each of the inlet passage and the outlet passage
is in fluid communication with the pump chamber and an outside of
the housing, wherein: the pump chamber has an inflow part at an
upstream end thereof, the inflow part of the pump chamber has an
inflow end at an upstream end thereof and has a hollow tapered
shape with a width that continuously decreases moving toward the
inflow end, the inlet passage includes a connection passage part
having a cylindrical shape coupled to the inflow end of the inflow
part and a main passage part having a cylindrical shape connected
to the connection passage part so as to form a bent shape, and a
central axis of the main passage part is oriented parallel to a
reference plane that includes a central axis of the connection
passage part such that a flow direction of a fluid along the
central axis of the main passage part is partly the same as the
rotational direction of the impeller in a plan view along the
rotational axis of the impeller.
2. The centrifugal pump of claim 1, wherein: the housing includes a
first pipe part defining the main passage part therein and a second
pipe part defining the connection passage part therein, the first
pipe part and the second pipe part are coupled to each other to
form a first connection part therebetween, and a corner is formed
at a part of the first connection part closer to the reference
plane in the plan view.
3. The centrifugal pump of claim 1, wherein a part of the main
passage part is in direct fluid communication with the inflow
part.
4. The centrifugal pump of claim 1, wherein: the outlet passage has
a cylindrical shape extending in a tangential direction from the
pump chamber such that a flow direction of the fluid along a
central axis of the outlet passage is substantially the same as the
rotational direction of the impeller at a second connection part
between the outlet passage and the pump chamber in the plan view,
and the central axis of the outlet passage is oriented parallel to
the central axis of the main passage part in the plan view.
5. A centrifugal pump, comprising: an impeller configured to be
rotated about a rotational axis in a rotational direction; and a
housing defining a pump chamber housing the impeller therein,
wherein the housing includes an inlet passage and an outlet
passage, wherein each of the inlet passage and the outlet passage
is in fluid communication with the pump chamber and an outside of
the housing, wherein: the pump chamber has an inflow part at an
upstream end thereof, the inflow part has an inflow end at an
upstream end thereof and has a hollow tapered shape with a width
that continuously decreases moving toward the inflow end, the inlet
passage includes a connection passage part having a cylindrical
shape coupled to the inflow end of the inflow part and a main
passage part having a cylindrical shape connected to the connection
passage part so as to form a bent shape, a central axis of the main
passage part is oriented parallel to a reference plane that
includes a central axis of the connection passage part, the housing
include a first pipe part defining the main passage part therein
such that the first pipe part includes a front wall and a rear wall
disposed rearward of the front wall relative to the rotational
direction in a plan view along the rotational axis of the impeller,
and a first distance between the reference plane and the front wall
is greater than a second distance between the reference plane and
the rear wall in the plan view.
6. The centrifugal pump of claim 5, wherein: the housing includes a
second pipe part defining the connection passage part therein, the
first pipe part and the second pipe part are coupled to each other
to form a first connection part therebetween, and a corner is
formed at a part of the first connection part closer to the
reference plane in the plan view.
7. The centrifugal pump of claim 5, wherein a part of the main
passage part is in direct fluid communication with the inflow
part.
8. The centrifugal pump of claim 5, wherein: the outlet passage has
a cylindrical shape extending in a tangential direction from the
pump chamber, such that a flow direction of a fluid along a central
axis of the outlet passage is substantially the same as the
rotational direction of the impeller at a second connection part
between the outlet passage and the pump chamber in the plan view,
and the central axis of the outlet passage is oriented parallel to
the central axis of the main passage part in the plan view.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to Japanese patent
application serial number 2019-044517, filed Mar. 12, 2019, which
is hereby incorporated herein by reference in its entirety for all
purposes.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
BACKGROUND
[0003] This disclosure relates generally to centrifugal pumps.
[0004] One type of centrifugal pump includes an impeller rotated by
a motor and a housing defining a pump chamber therein. The impeller
is housed in the pump chamber and includes a main plate having a
substantially circular shape and a plurality of blades on the main
plate. The housing has an inlet port and an outlet port that each
provide fluid communication between the inside and the outside of
the pump chamber. The inlet port extends upward from the pump
chamber and is coaxially aligned with the impeller.
[0005] Japanese Laid-Open Patent Publication No. 2015-190321
discloses another type of centrifugal pump in which the inlet port
of the housing is bent in an L-shape. In particular, an inlet
passage within the inlet port is divided into a connection passage
part and a main passage part. The connection passage part extends
upward from the pump chamber. The main passage part is connected to
an upstream end of the connection passage part at a right
angle.
BRIEF SUMMARY
[0006] In one aspect of this disclosure, a centrifugal pump
includes an impeller configured to be rotated about an axis of
rotation in a rotational direction and a housing defining a pump
chamber that houses the impeller therein. The housing includes an
inlet passage and an outlet passage, each of which provides fluid
communication between the pump chamber and the outside of the
housing. The pump chamber has an inflow part at an upstream end
thereof. The inflow part has an inflow end at an upstream end
thereof and may have a hollow tapered shape with a width that
continuously decreasing toward the inflow end. The inlet passage
includes a connection passage part that may have a cylindrical
shape coupled to the inflow end of the inflow part and a main
passage part that may have a cylindrical shape connected to the
connection passage part, so as to form a bent shape. A central axis
of the main passage part is oriented parallel to a reference plane
that includes a central axis of the connection passage part. The
main passage part is configured such that a flow direction of a
fluid parallel to the central axis of the main passage part is the
same as at least one part of the rotational direction of the
impeller in a plan view along the axis of rotation of the
impeller.
[0007] In accordance with this aspect, the main passage part is
configured such that a flow direction of fluid along the central
axis of the main passage part is same as the rotational direction
of the impeller in at least one place. Thus, when fluid flowing
linearly in the main passage part enters the connection passage
part, the fluid rotates in a same direction as the rotational
direction of the impeller while flowing through the connection
passage part. Accordingly, the fluid can smoothly flow from the
connection passage part into the inflow part of the pump chamber.
Accordingly, non-uniform distribution of the fluid on the impeller
can be reduced, thereby improving the performance of the
centrifugal pump.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] For a detailed description of the preferred embodiments of
the present teaching, reference will now be made to the
accompanying drawings.
[0009] FIG. 1 is a partial cross-sectional plan view of a first
embodiment of a centrifugal pump.
[0010] FIG. 2 is a cross-sectional view of the centrifugal pump of
FIG. 1, taken along section II-II of FIG. 1.
[0011] FIG. 3 is a cross-sectional view of the centrifugal pump of
FIG. 1, taken along section III-III of FIG. 1.
[0012] FIG. 4 is a cross-sectional view of a second embodiment of a
centrifugal pump.
[0013] FIG. 5 is a cross-sectional view of a third embodiment of a
centrifugal pump.
[0014] FIG. 6 is a cross-sectional view of a fourth embodiment of a
centrifugal pump.
[0015] FIG. 7 is a partial cross-sectional plan view of a fifth
embodiment of a centrifugal pump.
DETAILED DESCRIPTION
[0016] The following discussion is directed to various exemplary
embodiments. However, one skilled in the art will understand that
the examples disclosed herein have broad application, and that the
discussion of any embodiment is meant only to be exemplary of that
embodiment, and not intended to suggest that the scope of the
disclosure, including the claims, is limited to that
embodiment.
[0017] As previously described, Japanese Laid-Open Patent
Publication No. 2015-190321 discloses a centrifugal pump in which
the main passage part of the inlet is connected to the upstream end
of the connection passage part of the inlet at a right angle.
Consequently, a central axis of the main passage part is oriented
perpendicular to a central axis of the connection passage part.
Thus, fluid flowing through the main passage part tends to flow
into the far side of the connection passage part. As a result, the
volume of flow of the fluid proximal the far side of the connection
passage part is typically greater than the volume of flow of the
fluid proximal the near side of the connection passage part. This
causes the fluid to enter the pump chamber in an imbalanced manner,
such that the fluid is not dispersed uniformly over the impeller.
Such lack of uniformity in the fluid distribution decreases the
performance of the centrifugal pump. Therefore, there has been a
need for an improved centrifugal pump.
[0018] A first embodiment will be described with reference to FIGS.
1 to 3. The first embodiment of a centrifugal pump 10 is a purge
pump mounted on a vehicle, such as an automobile. The purge pump is
configured to compensate for a shortage of purge gas flowing from a
canister to an air intake passage of an internal combustion engine.
In each drawing, directions of the centrifugal pump 10 are
illustrated for convenience of explanation, however, these
directions do not limit a mounting direction of the centrifugal
pump 10 on the vehicle.
[0019] As shown in FIG. 2, the centrifugal pump 10 includes a
housing 11 having a substantially hollow cylindrical shape. The
housing 11 may be made from a resin material, a metal material, or
other suitable material. The centrifugal pump 10 also includes a
pump section 12 at an upper portion of the housing 11 and a motor
section 14 positioned below the pump section 12. The motor section
14 has a brushless motor and includes a rotational shaft 15
extending in the vertical direction. The motor section 14 may also
be referred to herein as "motor."
[0020] The housing 11 defines a pump chamber 17 in an upper portion
thereof. The pump chamber 17 has a hollow short cylindrical shape
and is coaxially aligned with the rotational shaft 15 of the motor
section 14. The housing 11 is divided into an upper housing member
11a and a lower housing member 11b coupled to the upper housing
member 11a. The pump chamber 17 is defined by the upper housing
member 11a and the lower housing member 11b. The rotational shaft
15 of the motor section 14 penetrates the lower housing member 11b
so as to protrude into the pump chamber 17.
[0021] The pump chamber 17 has an inflow part 18 positioned at a
center of an upper portion of the pump chamber 17 and a volute part
19 disposed at an outer circumferential part of the pump chamber
17. The inflow part 18 has an inflow end 18a at an upper end
thereof, such that fluid flows into the inflow part 18 via the
inflow end 18a. The inflow part 18 has a tapered shape with a width
that gradually decreases in cross-sectional area moving toward the
inflow end 18a, i.e. toward the upstream side.
[0022] The upper housing member 11a includes an inlet port 22 at an
upper portion thereof. The inlet port 22 is a tubular defining an
inlet passage 23 therein, such that the pump chamber 17 is in fluid
communication with the outside of the housing 11 via the inlet
passage 23. Details of the inlet passage 23 will be described
hereinbelow.
[0023] As shown in FIG. 1, the housing 11 includes an outlet port
27 having a hollow cylindrical shape extending leftward from a
front portion of the housing 11. In a plan view of the centrifugal
pump 10, the outlet port 27 extends tangentially from an outer
circumference of the housing 11, i.e. leftward. The outlet port 27
defines an outlet passage 28 therein, such that the volute part 19
of the pump chamber 17 is in a fluid communication with the outside
of the housing 11 via the outlet passage 28.
[0024] As shown in FIG. 2, an impeller 30 is rotatably housed in
the pump chamber 17. The impeller 30 includes a main plate 32 and a
plurality of blades 34 extending from the main plate 32. The main
plate 32 has a substantially circular plate shape in a plan view.
In addition, the main plate 32 has a convex part 32a having a
truncated conical shape at a central portion of an upper surface
thereof. The convex part 32a is coaxially positioned along the main
plate 32. The convex part 32a has a shaft hole 33 at a central
portion thereof. Shaft hole 33 is coaxially aligned with main plate
32 and rotational shaft 15. The blades 34 protrude upward from the
upper surface of the main plate 32 and extend in a substantially
radial direction along the upper surface of the main plate 32. Each
of the blades 34 has an elongated rectangular shape extending in
the radial direction of the impeller 30. A radially inner end of
each blade 34 is positioned in a lower portion of the inflow part
18 of the pump chamber 17. The impeller 30 may be made from a resin
material, metal material, or other suitable material.
[0025] The rotational shaft 15 of the motor section 14 is inserted
into the shaft hole 33 of the impeller 30 and fixably secured
thereto. Thus, when the motor section 14 is running, the impeller
30 rotates with the rotational shaft 15. As shown in FIG. 1, in the
plan view of the centrifugal pump 10, the impeller 30 rotates about
its central axis in a rotational direction R in a clockwise
direction.
[0026] When the motor section 14 is driven using electricity
supplied from an external power source, the impeller 30 is rotated
together with the rotational shaft 15, so that fluid, i.e. purge
gas in this embodiment, is suctioned into the pump chamber 17 via
the inlet passage 23. The purge gas is pressurized and then
discharged into the outflow passage 28 via rotation of the impeller
30. The purge gas may be pumped by the centrifugal pump 10 in this
manner.
[0027] As shown in FIG. 2, the inlet passage 23 is divided into a
main passage part 24 and a connection passage part 25, each of
which has a cylindrical cross-sectional shape. The connection
passage part 25 extends upward from the inflow end 18a of the
inflow part 18. The main passage part 24 is connected to the
connection passage part 25, so as to extend radially outward from
the connection passage part 25 and form a bent shape therewith.
More specifically, in this embodiment, the main passage part 24 is
connected to the connection passage part 25 to form substantially a
right angle along one plane, for instance a plane including the
left-right and front-rear directions with the main passage part 24
extending rightward. The connection passage part 25 has the same
inner diameter as the inflow end 18a. The inner diameter of the
main passage part 24 is equal to or greater than the inner diameter
of the connection passage part 25. For example, the inner diameter
of the main passage part 24 may be about one and a half times
greater than the inner diameter of the connection passage part
25.
[0028] FIG. 1 illustrates a reference plane 25s containing a
central axis 25c of the connection passage part 25 and extending
radially in the right-left direction, and oriented parallel to a
central axis 24c of the main passage part 24. In the plan view of
the centrifugal pump 10 of FIG. 1, the central axis 24c of the main
passage part 24 is positioned in front of (and oriented parallel
to) the reference plane 25s. That is, the central axis 24c of the
main passage part 24 deviates forward from the reference plane 25s
by an offset distance L such that a flow direction F parallel to
the central axis 24c is substantially the same as the rotational
direction R of the impeller 30 in at least one place in the plan
view of the centrifugal pump 10. The central axis 25c of the
connection passage part 25 is coaxially aligned with the rotational
axis of the impeller 30.
[0029] In the plane view of the centrifugal pump 10, the main
passage part 24 is directly connected to the connection passage
part 25, on one side of the connection part closer to the reference
plane 25s (the rear side in FIG. 1), such that an inner surface 24a
of the main passage part 24 and an inner surface 25a of the
connection passage part 25 form a sharp corner 26 having a convex
shape. The inlet port 22 includes an inclined surface 29,
connecting the main passage part 24 to the connection passage part
25, on the other side farther from the reference plane 25s (the
front side in FIG. 1), such that the inner surface 24a is gently
continued to the inner surface 25a via the inclined surface 29.
[0030] As shown in FIG. 2, the inflow end 18a of the pump chamber
17 is positioned proximal the midpoint between the central axis 24c
and a bottom surface 24b of the main passage part 24 in the
vertical direction. Due to this arrangement, a part of the main
passage part 24 is in direct fluid communication with the inflow
part 18. More specifically, a lower end part of the main passage
part 24 is in direct fluid communication with the upper end of the
inflow part 18.
[0031] As shown in FIG. 1, the outlet port 27 has a hollow
cylindrical cross-sectional shape defining the outlet passage 28
therein. The outlet passage 28 extends in a tangential direction
from the pump chamber 17, such that a flow direction in the outlet
passage 28 is substantially the same as the rotational direction R
at a connection portion between the outlet passage 28 and the pump
chamber 17. The inlet port 22 extends rightward, and the outlet
port 27 extends leftward. So, the central axis 24c of the main
passage part 24 is oriented parallel to a central axis 28c of the
outlet passage 28. In this embodiment, the plan view of the
centrifugal pump 10 corresponds to a view along an axial direction
of the pump chamber 17. The term "parallel" may include
"substantially parallel."
[0032] In accordance with the first embodiment, the central axis
24c of the main passage part 24 is not included in the reference
plane 25s, the plane which includes the central axis 25c of the
connection passage part 25, such that the flow direction F along
the central axis 24c is substantially the same as the rotational
direction R of the impeller 30 in at least one place, in the plan
view of the centrifugal pump 10. Thus, when the fluid flowing in
the main passage part 24 enters the connection passage part 25, the
fluid rotates in a same direction S as the rotational direction R
of the impeller 30 while flowing through the connection passage
part 25. That is, while the fluid flows through the connection part
25, it has a rotational flow component. As a result, flow of the
fluid can smoothly transition from the connection passage part 25
into the inflow part 18 of the pump chamber 17. Accordingly,
non-uniform distribution of the fluid on the impeller 30 can be
reduced, thereby improving the performance of the centrifugal pump
10.
[0033] As previously described, the main passage part 24 and the
connection passage part 25 intersect at the sharp corner 26 on the
one side closer to the reference plane 25s. The sharp corner 26
facilitates generation of the rotational flow in the connection
passage part 25, thereby improving the performance of the
centrifugal pump 10, in comparison with a case where the main
passage part 24 gently transitions to the connection passage part
25, without the sharp corner 26.
[0034] A part of the main passage part 24 is in direct fluid
communication with the inflow part 18. Thus, a part of the fluid
flowing through the main passage part 24 can flow directly into the
inflow part 18 of the pump chamber 17, without passing through the
connection passage part 25. This reduces the moving distance of a
portion of the fluid flow. Accordingly, in comparison with a case
where the whole of the main passage part 24 is indirectly connected
to the inflow part 18 via the connection passage part 25, the
performance of the centrifugal pump 10 can be increased.
[0035] In the plan view of the centrifugal pump 10, the central
axis 24c of the main passage part 24 is oriented parallel to the
central axis 28c of the outlet passage 28. Thus, in comparison with
a case where the central axes 24c, 28c are not oriented parallel
with each other in the plan view of the centrifugal pump 10, a pipe
can be easily connected to each of the main passage part 24 and the
outlet passage 28, thereby improving the mountability of the
centrifugal pump 10 on a vehicle, etc. In the plan view of the
centrifugal pump 10, the inlet passage 23 may be oriented in the
same direction as the outlet passage 28, e.g. leftward in FIG.
1.
[0036] A second embodiment will be described with reference to FIG.
4. The second embodiment is substantially the same as the first
embodiment described above, with some differences regarding the
inlet passage 23. Thus, while the differences will be described,
similar configurations will not be described in the interest of
conciseness. As shown in FIG. 4, the bottom surface 24b of the main
passage part 24 is even with the inflow end 18a of the pump chamber
17, in the vertical direction. Due to this configuration, the main
passage part 24 is indirectly connected, via the connection passage
part 25, to the inflow part 18. Thus, the axial length of the
connection passage part 25 is longer than that of the first
embodiment.
[0037] A third embodiment will be described with reference to FIG.
5. The third embodiment is substantially the same as the first
embodiment described above, with some differences regarding the
inlet passage 23. Thus, while the differences will be described,
similar configurations will not be described in the interest of
conciseness. As shown in FIG. 5, the bottom surface 24b of the main
passage part 24 is positioned above the inflow end 18a of the pump
chamber 17 in the vertical direction. Accordingly, the main passage
part 24 is indirectly connected, via the connection passage part
25, to the inflow part 18 such that the axial length of the
connection passage part 25 is longer than those of both the first
embodiment and the second embodiment.
[0038] A fourth embodiment will be described with reference to FIG.
6. The fourth embodiment is substantially the same as the first
embodiment described above, with some differences regarding the
inlet passage 23. Thus, while the differences will be described,
similar configurations will not be described in the interest of
conciseness. As shown in FIG. 6, the main passage part 24 extends
obliquely upward, such that an angle formed by the central axis 24c
of the main passage part 24 and the central axis 25c of the
connection passage part 25 is about 110 degree. The degree of
inclination can be set freely based on various requirements, such
as a mounting space.
[0039] A fifth embodiment will be described with reference to FIG.
7. The fifth embodiment is substantially the same as the first
embodiment described above, with some differences regarding the
outlet passage 28. Thus, while the differences will be described,
similar configurations will not be described in the interest of
conciseness. As shown in FIG. 7, the main passage part 24 extends
in the right-left direction, and the outlet passage 28 extends in
the front-rear direction, such that the central axis 24c of the
main passage part 24 is oriented perpendicular to the central axis
28c of the outlet passage 28 in the plan view of the centrifugal
pump 10. The outlet passage 28 may be oriented such that the
central axis 28c crosses the central axis 24c at any angle. The
term "perpendicular" includes "substantially perpendicular" in this
disclosure.
[0040] As stated above, the technique disclosed in this application
is not limited to the above-described embodiments. For example, the
centrifugal pump 10 may be used for pumping various fluids, such as
air, other than the above described purge gas. The brushless motor
of the motor section 14 may be replaced with a brushed motor. The
centrifugal pump 10 may be composed of the pump section 12 only,
such that the rotational shaft 15 is rotated by a driving source
that is provided outside the centrifugal pump 10. The impeller 30
may be made from a metal or other material.
* * * * *