U.S. patent application number 14/761987 was filed with the patent office on 2015-12-10 for side-channel pump with asymmetrical cross-sections of the side channels.
The applicant listed for this patent is Robert Bosch GmbH. Invention is credited to Ina Constantinides, Michael Kuehn, Paul Skljarow.
Application Number | 20150354573 14/761987 |
Document ID | / |
Family ID | 49918710 |
Filed Date | 2015-12-10 |
United States Patent
Application |
20150354573 |
Kind Code |
A1 |
Kuehn; Michael ; et
al. |
December 10, 2015 |
SIDE-CHANNEL PUMP WITH ASYMMETRICAL CROSS-SECTIONS OF THE SIDE
CHANNELS
Abstract
The invention relates to a side-channel pump that allows a
reduced wear. The side-channel pump has a housing which encloses a
pump chamber (7). An impeller (3) is received so as to be rotatable
inside the pump chamber (7). An inlet side channel (31) and an
outlet side channel (33) are also formed inside the pump chamber
(7). The impeller (7) has, in a blade region near the circumference
thereof, a plurality of radially outward-extending blades (11). The
inlet side channel (31) and the outlet side channel (33) run on
opposite sides of the impeller (3) and both adjoin the impeller
(3). The two side channels (31, 33) both extend in a partially
annular shape along a flow path from an inlet channel to an outlet
channel. The proposed side-channel pump is characterized in that
the inlet side channel (31), averaged along the flow path, has a
smaller cross-section than the outlet side channel (33). In this
manner the impeller (3) can be maintained in a force equilibrium
during operation. The friction between the impeller (3) and
adjoining walls (19, 21) can be kept small and thereby wear
phenomena can be kept small.
Inventors: |
Kuehn; Michael;
(Bietigheim-Bissingen, DE) ; Skljarow; Paul;
(Schwieberdingen, DE) ; Constantinides; Ina;
(Gerlingen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Robert Bosch GmbH |
Stuttgart |
|
DE |
|
|
Family ID: |
49918710 |
Appl. No.: |
14/761987 |
Filed: |
January 2, 2014 |
PCT Filed: |
January 2, 2014 |
PCT NO: |
PCT/EP2014/050017 |
371 Date: |
July 20, 2015 |
Current U.S.
Class: |
417/68 ;
417/70 |
Current CPC
Class: |
F04D 5/001 20130101;
F05B 2250/503 20130101; F04D 5/008 20130101 |
International
Class: |
F04D 5/00 20060101
F04D005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 18, 2013 |
DE |
10 2013 200 713.2 |
Claims
1. A side channel pump (1), having: a housing (5) which encloses a
pump chamber (7), an impeller (3) which is accommodated within the
pump chamber (7) such that the impeller can rotate, and, within the
pump chamber (7), an inlet-side side channel (31) and an
outlet-side side channel (33); the housing (5) having an inlet
channel (35) which opens into the inlet-side side channel (31) and
an outlet channel (37) which leads away from the outlet-side side
channel (33); the impeller (3) having, in a blade region close to
an outer circumference (9) of the impeller, a multiplicity of
radially outwardly extending blades (11), the inlet-side side
channel (31) and the outlet-side side channel (33) running on
opposite sides of the impeller (3) and adjoining the impeller (3),
and the two side channels (31, 33) in each case extending along a
flow path (39) from the inlet channel (35) in a partially annular
manner to the outlet channel (37), characterized in that the
inlet-side side channel (31) has, averaged along the flow path
(39), a smaller cross section than the outlet-side side channel
(33).
2. The side channel pump as claimed in claim 1, the inlet-side side
channel (31) having a smaller cross section at at least 50% of
positions along the flow path (39) than the outlet-side side
channel (33) at the same position along the flow path (39).
3. The side channel pump as claimed in claim 1, the inlet-side side
channel (31) having, at at least 50% of positions along the flow
path (39), a cross section which is smaller by between 5% and 30%
than the outlet-side side channel (33) at the same position along
the flow path (39).
4. The side channel pump as claimed in claim 1, the inlet-side side
channel (31) having a smaller depth at at least 50% of the
positions along the flow path (39) than the outlet-side side
channel (33) at the same position along the flow path (39).
5. The side channel pump as claimed in claim 4, the inlet-side side
channel (31) having, at at least 50% of the positions along the
flow path (39), a depth which is smaller by between 5% and 30% than
the outlet-side side channel (33) at the same position along the
flow path (39).
6. A fuel pump for a motor vehicle, having a side channel pump (1)
as claimed in claim 1.
7. The side channel pump as claimed in claim 2, the inlet-side side
channel (31) having, at at least 50% of the positions along the
flow path (39), a cross section which is smaller by between 5% and
30% than the outlet-side side channel (33) at the same position
along the flow path (39).
8. The side channel pump as claimed in claim 7, the inlet-side side
channel (31) having a smaller depth at at least 50% of the
positions along the flow path (39) than the outlet-side side
channel (33) at the same position along the flow path (39).
9. The side channel pump as claimed in claim 8, the inlet-side side
channel (31) having, at at least 50% of the positions along the
flow path (39), a depth which is smaller by between 5% and 30% than
the outlet-side side channel (33) at the same position along the
flow path (39).
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a side channel pump for
delivering fluids. Furthermore, the invention relates to a fuel
pump having a side channel pump of this type.
[0002] Fluids such as liquids and gases can be delivered and/or
pressurized by way of different types of pumps. In motor vehicles,
in particular, pumps are frequently used to deliver fuel from a
tank to an internal combustion engine. For this purpose, the pump
should have the capability of delivering fuel reliably and in a
sufficient quantity under various ambient conditions. For example,
the fuel should be capable of being delivered both in the case of a
cold start and in the case of pronounced heating, in the case of
which the formation of gas bubbles within the fuel can occur
readily. Furthermore, the pump should have a long service life and
should be capable of retaining its delivery properties reliably
over a long service life of, for example, more than 10 years.
[0003] What are known as side channel pumps are therefore
frequently used for delivering fuel in motor vehicles, since they
are both robust during usage and can be manufactured and assembled
inexpensively and simply. However, it has been observed that, in
the case of conventional side channel pumps, a long service life is
partially not achieved or that at least considerable wear phenomena
occur over the service life of the pump.
[0004] DE 43 43 078 B4, U.S. Pat. No. 4,591,311 and DE 43 00 845 A1
describe conventional side channel pumps.
SUMMARY OF THE INVENTION
[0005] Embodiments of the present invention make it advantageously
possible to increase the service life of a side channel pump or a
fuel pump which is equipped with a side channel pump of this type
and/or to keep wear phenomena low.
[0006] A side channel pump is proposed which has a housing which
encloses a pump chamber. An impeller is accommodated within the
pump chamber such that it can rotate. Furthermore, an inlet-side
side channel and an outlet-side side channel are configured within
the pump chamber. The housing has an inlet channel which opens into
the inlet-side side channel and an outlet channel which leads away
from the outlet-side side channel. The impeller has, in a blade
region close to its outer circumference, a multiplicity of radially
outwardly extending blades. The inlet-side side channel and the
outlet-side side channel run on opposite sides of the impeller and
both adjoin the impeller. The two side channels both extend along a
flow path from the inlet channel in a partially annular manner to
the outlet channel. The side channel pump which is proposed is
distinguished by the fact that the inlet-side side channel has,
averaged along the flow path, a smaller cross section than the
outlet-side side channel.
[0007] The side channel pump which is proposed can be considered to
be based on the findings and concepts which are explained in the
following text.
[0008] In side channel pumps, a fluid to be delivered is sucked in
through the inlet channel into the pump chamber. The impeller
rotates in the pump chamber, for example driven by an electric
motor. The blades of the impeller act on the fluid in such a way
that parts of the fluid are carried along. Side channels are
situated in a manner which is adjacent to the blades of the
impeller on both opposite sides of the impeller. The inlet channel
opens into the inlet-side side channel.
[0009] Since both side channels adjoin the impeller and are open
toward the blades of the impeller, fluid which is sucked in through
the inlet channel can firstly pass to the blades of the rotating
impeller and can be carried along by the blades which move parallel
to the side channels, and secondly a proportion of the fluid which
is sucked in can also pass the blades and can pass between two
adjacent blades toward the opposite outlet-side side channel. Here,
the blades of the impeller interact with the fluid in such a way
that the fluid is partially carried along in the rotational
direction of the impeller and is partially pressed away from the
impeller toward one of the side channels. As a result, after it has
flowed through the inlet channel into the pump chamber, the fluid
moves in a spiral manner along a flow path which leads from the
inlet channel along the side channels toward the outlet channel.
During this spiral movement, a considerable amount of energy is
transmitted from the impeller to the fluid, with the result that
the fluid can be delivered to the outlet channel and at the same
time it can be pressurized and can then leave the pump chamber
through the outlet channel.
[0010] It has now been observed that a force is exerted on the
impeller by way of the intake of the fluid through the inlet
channel, the throughflow of the fluid between the blades of the
impeller and/or by way of the ejection of the fluid through the
outlet channel, which force causes the impeller to be displaced in
the direction toward the inlet side. On account of a force of this
type, the impeller can rub on an inlet-side wall of the housing or,
for example, of an intake cover during operation of the pump, which
can lead to wear and to a considerable drop in the delivery
capacity of the pump.
[0011] It has been recognized that the single-sided force loading
of the impeller which has been observed can be avoided or at least
reduced during operation of the pump by virtue of the fact that the
two side channels are configured with different cross-sectional
areas. Here, the cross section of the inlet-side side channel
should have, averaged over the entire flow path, a smaller cross
section than the outlet-side side channel. However, this does not
rule out that the inlet-side side channel can have a larger cross
section in small parts of the flow path, such as directly
adjacently with respect to the inlet channel, than the opposite
outlet-side side channel. However, the inlet-side side channel
should have, over preferably considerably more than half the flow
path, that is to say, for example, over at least 50%, preferably
over at least 60% and, more preferably, over at least 75% of the
flow path between the inlet channel and the outlet channel, a
smaller cross section than the outlet-side side channel.
[0012] In other words, according to one embodiment of the
invention, the inlet-side side channel has, at at least 60%,
preferably at least 75% or 90% of the positions along the flow
path, a smaller cross section than the outlet-side side channel at
the same position along the flow path.
[0013] It has been recognized that, by way of an asymmetrical
configuration of this type of the two side channels, a force can be
brought about on the impeller, which force can counteract the
otherwise observed force described further above and can compensate
for said force at least partially. This can achieve a situation
where the impeller is no longer pressed excessively toward the
inlet side during operation, with the result that wear phenomena
which are associated with this can be avoided or considerably
reduced.
[0014] According to one embodiment, the inlet-side side channel
has, at at least 50% of the positions along the flow path, a cross
section which is smaller by between 5% and 30%, preferably between
10% and 25%, than the outlet-side side channel at the same position
along the flow path. It has been observed that even minor
asymmetries of this type with regard to the channel cross sections
can lead to a considerable reduction of undesired forces on the
impeller and therefore to reduced wear.
[0015] According to one embodiment, the inlet-side side channel
has, at at least 50% of the positions along the flow path, a
smaller depth than the outlet-side side channel at the same
position along the flow path. In other words, the asymmetry of the
cross sections of the side channels can be implemented mainly by
way of a modification of the depths of the two side channels which
is simple to implement. Here, the depths of the two side channels
can differ from one another, for example, by between 5% and 30%,
preferably between 10% and 25%.
[0016] It is noted that possible features and advantages of the
invention are described herein in relation to different embodiments
of the side channel pump. A person skilled in the art will
recognize that features can be combined or replaced in a suitable
way, in order for it to be possible in this way to arrive at
further embodiments and possibly synergistic effects.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In the following text, embodiments of the invention will be
described with reference to the appended drawings; neither the
drawings nor the description are to be considered to restrict the
invention, however. In the drawings:
[0018] FIG. 1 shows a perspective, partially cut-away view of a
side channel pump.
[0019] FIG. 2 shows an exploded view of a pump part of a side
channel pump.
[0020] FIG. 3 shows a plan view of a housing part of a side channel
pump with a side channel which is configured therein.
[0021] FIG. 4 shows a greatly diagrammatic cross-sectional view
through a pump chamber and adjoining housing parts of a
conventional side channel pump.
[0022] FIG. 5 shows a greatly diagrammatic cross-sectional view
through a pump chamber and adjoining housing parts of a side
channel pump according to one embodiment of the present
invention.
[0023] The figures are merely diagrammatic and are not true to
scale. Identical or similar features are denoted in the figures by
identical designations.
DETAILED DESCRIPTION
[0024] FIG. 1 shows the essential construction of a side channel
pump 1. In the side channel pump 1, an impeller 3 which is in part
also called an impeller wheel is accommodated within a pump chamber
7 which is enclosed by a housing 5. Close to its outer
circumference 9, the impeller 3 has a multiplicity of blades 11
which run at least partially in the radial direction. Here, the
impeller 3 can move rotationally within the pump chamber 7 and is
set in rotation during operation of the pump 1, for example by an
electric motor 13 which is coupled to the impeller 3 via a shaft
29. The housing 5 is configured in such a way that parts of the
housing 5, which are also called the intake cover 15 and the
intermediate housing 17, form walls 19, 21 which adjoin the end
faces of the disk-shaped impeller 3 over predominant regions and
are spaced apart from said end faces at any rate by a narrow gap
23.
[0025] During operation of the side channel pump 1, the impeller 3
is set in rotation by the electric motor 13 via a shaft 29 which is
connected to said two components. By the blades 11 of the impeller
3 interacting with the fluid in the pump chamber 7, fuel, for
example, coming from a tank via a line (not shown) is sucked into
the pump chamber 7 through an inlet 25 which reaches through the
housing 5. As a result of the rotation of the impeller 3 and the
blades 11 which are arranged thereon, the fluid is pressurized, is
conveyed through the pump chamber and is finally ejected through an
outlet 27, for example, toward an internal combustion engine (not
shown).
[0026] In the side channel pump 1 which is shown by way of example
in FIG. 1, the impeller 3 is enclosed by the housing 5 and, in
particular, by the intake cover 15 and the intermediate housing 17.
As can be seen in the exploded view from FIG. 2, the impeller 3 is
accommodated here within the space which is enclosed by the intake
cover 15 and the intermediate housing 17. Furthermore, a free
volume remains within said space, through which free volume a fluid
can flow and which free volume is called a pump chamber 7. Here,
the pump chamber 7 is formed by an inlet-side side channel 31 which
is configured in the intake cover 15, an outlet-side side channel
33 which is configured in the intermediate housing 17, and a free
volume between the blades 11 of the impeller 3. With the exception
of the region of the pump chamber 7, walls 19, 21 of the intake
cover 15 and the intermediate housing 17 adjoin corresponding end
faces of the impeller 3 almost directly, said walls 19, 21 being
spaced apart from said end faces at any rate by a narrow gap of,
for example, 100 .mu.m.
[0027] Fluid to be delivered comes from the inlet 25 and reaches
the pump chamber 7 via an inlet channel 35 which opens into the
inlet-side side channel 31. From there, the fluid is distributed
over the pump chamber 7, that is to say also into regions between
the blades 11 of the impeller 3 and into the opposite outlet-side
side channel 33. Here, driven by the rotating impeller 3, it moves
along a flow path 39 (see FIG. 3) which reaches from the inlet
channel 35 as far as toward an outlet channel 37. Here, the fluid
flows partially through the inlet-side side channel 31, partially
through the outlet-side side channel 33 and is partially carried
along by the blades 11 of the impeller. Here, the fluid circulates
in a spiral movement between the individual part regions of the
pump chamber 7. The fluid which is pressurized here leaves the pump
chamber 7 through the outlet channel 37, flows through the electric
motor 13 in the example which is shown in FIG. 1, and then leaves
the housing 5 through the outlet 27.
[0028] As can be seen in the plan view from FIG. 3, the inlet-side
side channel 31 which is configured in the intake cover 15 reaches
from the inlet channel 35 in an annular manner along the flow path
39 in a part circle of approximately 300.degree. as far as toward a
region 41, at which, in the opposite intermediate housing 17, the
outlet-side side channel 33 there leads into the outlet channel 37.
Here, it passes a degassing bore 43.
[0029] FIG. 4 shows the configuration of an intake cover 15, an
intermediate housing 17 and the impeller 3 which is accommodated
therein for the case of a conventional side channel pump. FIG. 5
shows a corresponding configuration for a side channel pump
according to one embodiment of the present invention.
[0030] In the conventional pump according to FIG. 4, the inlet-side
side channel 31 and the outlet-side side channel 33 are dimensioned
with identical widths B and identical depths KT1, KT2 and therefore
have identical cross sections with an otherwise identical
shape.
[0031] Although the two side channels 31, 33 are therefore of
symmetrical configuration with regard to a plane through the center
of the impeller 3, it has been observed that a force F.sub.1 which
is exerted on the impeller 3 on account of the pressure which is
built up in the inlet-side side channel 31 is smaller than a force
F.sub.2 which is exerted on the impeller 3 in the opposite
direction on account of the pressure which is built up in the
outlet-side side channel 33. Since the two forces F.sub.1, F.sub.2
which are directed in opposite directions therefore compensate for
one another only partially, a resulting force F.sub.2-F.sub.1 acts
on the impeller 3, which force presses the impeller 3 toward the
inlet-side intake cover 15. Here, the impeller 3 can come into
mechanical contact with the intake cover 15, that is to say without
a gap 23 which lies in between. Solid body friction can therefore
occur between the impeller 3 and the intake cover 15, which solid
body friction is substantially more pronounced than liquid
friction, as occurs as long as the impeller 3 is spaced apart from
the intake cover 15 via a gap 23 and the fluid to be delivered,
that is to say low-viscosity fuel, for example, can flow through
the gap.
[0032] In the side channel pump 1 according to one embodiment of
the present invention, as shown in FIG. 5, although the inlet-side
side channel 31 and the outlet-side side channel 33 are configured
with identical widths B, they have different depths KT.sub.1,
KT.sub.2. Their cross sections therefore differ and they are
asymmetrical with regard to a plane which runs transversely with
respect to the side channels 31, 33 and centrally through the
impeller 3.
[0033] The channel depths KT.sub.1, KT.sub.2 can differ from one
another, for example, by from 10% to 25%. For example, the two
channel depths KT.sub.1, KT.sub.2 can lie in the range from 1 to 2
mm, but the channel depth KT.sub.1 of the inlet-side side channel
31 can be smaller by from 0.1 to 0.2 mm than the channel depth
KT.sub.2 of the outlet-side side channel 33.
[0034] Instead of giving different dimensions only to the channel
depths KT.sub.1, KT.sub.2 of the two side channels 31, 33, in
principle as an alternative or in addition the width and/or shape
of the side channels 31, 33 can also be selected to be different in
such a way that the cross section of the inlet-side side channel 31
is somewhat smaller than that of the outlet-side side channel
33.
[0035] It has been observed that a relative reduction of this type
in the cross section of the inlet-side side channel 31 can achieve
a situation where the force F.sub.1 which is exerted on the
impeller 3 on account of the pressure which is built up in the
inlet-side side channel 31 is approximately as great as a force
F.sub.2 which is exerted on the impeller 3 in the opposite
direction on account of the pressure which is built up in the
outlet-side side channel 33.
[0036] On account of the therefore equalized balance of forces on
the impeller 3, the latter is no longer loaded or even displaced in
the axial direction. Gaps 23 can therefore be ensured between both
end faces and respectively adjoining walls 19, 21 of the intake
cover 15 or the intermediate housing 17. The spacing which prevails
in this way of the impeller 3 from the adjoining walls 19, 21 and
the low liquid friction which prevails as a result between the end
faces of the impeller 3 and said side walls 19, 21 can contribute
to reduced wear phenomena and therefore to an increased service
life of the side channel pump 1.
* * * * *