EP2946116A1

EP2946116A1 - Side-channel pump with asymmetrical cross-sections of the side channels

Info

Publication number: EP2946116A1
Application number: EP14700029.3A
Authority: EP
Inventors: Ina Constantinides; Paul Skljarow; Michael Kuehn
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2013-01-18
Filing date: 2014-01-02
Publication date: 2015-11-25
Also published as: WO2014111272A1; CN104937276A; US20150354573A1; DE102013200713A1

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.

Description

description

Side channel pump with asymmetrical cross sections of the side channels

Field of the invention

The present invention relates to a side channel pump for conveying fluids. Furthermore, the invention relates to a fuel pump with such a side channel pump.

State of the art

Fluids such as liquids and gases can be pumped and / or pressurized with different types of pumps. In particular in

Automotive vehicles are often used to pump fuel from a tank to an internal combustion engine. The pump should for this purpose have the ability to deliver fuel reliably and in sufficient quantity under different environmental conditions. For example, the fuel should be able to be pumped both during a cold start and during high heating, which can easily lead to gas bubble formation within the fuel. Furthermore, the pump should be durable and have a long life of for example more than 10 years

Can reliably maintain conveying properties.

For conveying fuel in motor vehicles, therefore, so-called side channel pumps are often used, since they are both robust in use and inexpensive and easy to manufacture and assemble. However, it has been observed that in conventional side channel pumps, in some cases, a long service life is not attained, or that at least considerable signs of wear occur over the life of the pump. In DE 43 43 078 B4, US 4,591,311 and DE 43 00 845 AI conventional side channel pumps are described.

Disclosure of the invention

Embodiments of the present invention advantageously allow to increase the longevity of a side channel pump or a fuel pump equipped with such a side channel pump and / or to minimize wear phenomena.

It is proposed a side channel pump, which has a housing which encloses a pumping chamber. Within the pumping chamber, an impeller is rotatably received. Furthermore, within the pumping chamber a

inlet side channel and an outlet side channel formed. The housing has a opening into the inlet side channel

Inlet channel and a discharge from the outlet side channel outlet. The impeller has near its outer periphery in a blade region a plurality of radially outwardly extending ones

Shovels up. The inlet side channel and the outlet side channel run on opposite sides of the impeller and both abut the impeller. The two side channels both extend along one

Flow path of the inlet channel partially annular to the outlet channel. The proposed side channel pump is characterized in that the inlet side channel averaged along the flow path has a smaller cross section than the outlet side channel.

The proposed side channel pump may be considered to be based on the findings and ideas discussed below.

In side channel pumps, a fluid to be delivered is sucked through the inlet channel into the pumping chamber. In the pumping chamber, the impeller rotates, driven for example by an electric motor. The blades of the impeller act on the fluid such that parts of the fluid are entrained.

Adjacent to the blades of the impeller are at both opposite sides of the impeller side channels. The inlet channel opens into the inlet side channel.

Since both side channels are adjacent to the impeller and open towards the vanes of the impeller, fluid drawn in through the inlet duct may, on the one hand, reach the vanes of the rotating impeller and be entrained by the vanes moving parallel to the side ducts, on the other hand a portion of the sucked Fluids also past the blades and between two adjacent blades through to the

opposite outlet side channel go. The blades of the

Impellers interact with the fluid in such a way that the fluid is partially entrained in the direction of rotation of the impeller and is partially pressed away from the impeller to one of the side channels. As a result, the fluid, after it has flowed through the inlet channel into the pumping chamber, spirals along a flow path that runs from the inlet channel along the

Side channels leads to the outlet channel. During this spiraling motion, energy is transferred to the fluid from the impeller substantially, so that the fluid can be delivered to the exhaust passage while being pressurized and then leaving the pump chamber through the exhaust passage.

It has now been observed that by the suction of the fluid through the inlet channel, the passage of the fluid between the blades of the

Impeller and / or by the ejection of the fluid through the outlet channel, a force is exerted on the impeller, which tries to move the impeller toward the inlet side. Due to such a force, the impeller may rub during operation of the pump on an inlet side wall of the housing or, for example, a suction cover, which can lead to wear and to a significant drop in the delivery rate of the pump.

It has been recognized that the observed unilateral force applied to the impeller during operation of the pump can be avoided or at least reduced by having the two side channels formed with different cross-sectional areas. In this case, the cross section of the inlet-side side channel should have a smaller cross-section over the entire flow path than the outlet-side side channel. This concludes however, it is not to be understood that the inlet side channel has a larger cross section than the opposite outlet side in small parts of the flow path, such as directly adjacent to the inlet channel

Side channel. However, the inlet side channel should preferably over substantially more than half of the flow path, i. For example, over at least 50%, preferably over at least 60%, and more preferably over at least 75%, of the flowpath between the inlet channel and the outlet channel has a smaller cross-section than the outlet side channel.

In other words, the inlet-side channel according to a

Embodiment of the invention 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.

It has been recognized that by such an asymmetric design of the two side channels, a force can be exerted on the impeller, which can counteract the force otherwise observed above and at least partially compensate for it. This can be achieved that the impeller is no longer excessively pressed during operation to the inlet side, so that associated wear and tear can be avoided or significantly reduced.

According to an embodiment, the inlet-side side channel has at least 50% of the positions along the flow path a smaller by between 5% and 30%, preferably between 10% and 25% smaller cross section than the outlet side channel at the same position along the

Flow path. It has been observed that even such minor asymmetries in the channel cross-sections to a significant reduction of undesirable forces on the impeller and thus reduced

Wear can cause.

According to an embodiment, the inlet-side side channel has a smaller depth at at least 50% of the positions along the flow path 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 achieved mainly by an easy-to-implement

Modification of the depths of the two side channels can be implemented. The depths of the two side channels may differ, for example, between 5% and 30%, preferably between 10% and 25%.

It should be noted that possible features and advantages of the invention are described herein with reference to different embodiments of the side channel pump. One skilled in the art will recognize that features may be suitably combined or replaced so as to provide further embodiments and possibly synergy effects.

Brief description of the drawings

Hereinafter, embodiments of the invention will be described with reference to the accompanying drawings, but neither the drawings nor the description shall be construed as limiting the invention.

Fig. 1 shows a perspective, partially cut away view

Side channel pump.

Fig. 2 shows an exploded view of a pump part of a

Side channel pump.

Fig. 3 shows a plan view of a housing part of a side channel pump with a side channel formed therein.

Fig. 4 shows a highly schematic of a cross-sectional view through a

Pumping chamber and adjacent housing parts of a conventional

Side channel pump.

Fig. 5 shows a highly schematic of a cross-sectional view through a

Pumping chamber and adjacent housing parts of a side channel pump according to an embodiment of the present invention. The figures are only schematic and not to scale. Identical or similar features are denoted by the same reference numerals in the figures. Embodiments of the invention

1 shows the essential structure of a side channel pump 1. In the side channel pump 1 is an impeller 3, which is sometimes also referred to as an impeller, enclosed within a housing 5 of a housing

Pump chamber 7 was added. The impeller 3 has near its outer periphery

9 a plurality of blades 11 which extend at least partially in the radial direction. The impeller 3 can thereby rotate within the pumping chamber 7 and is set during operation of the pump 1, for example, by a coupled to the impeller 3 via a shaft 29 electric motor 13 in rotation. The housing 5 is designed such that parts of the

Housing 5, which are also referred to as suction cover 15 and intermediate housing 17, walls 19, 21 form, which border on predominant areas of the end faces of the disk-shaped impeller 3 and spaced from these at best by a narrow gap 23.

During operation of the side channel pump 1, the impeller 3 is rotated by the electric motor 13 via a shaft 29 connected to these two components. As the blades 11 of the impeller 3 interact with the fluid in the pumping chamber 7, e.g. Fuel from a tank via a line (not shown) coming sucked through an extending through the housing 5 inlet 25 into the pumping chamber 7. By the rotation of the impeller 3 and the blades 11 disposed thereon, the fluid is pressurized, conveyed through the pumping chamber, and finally through an outlet 27, e.g. towards an internal combustion engine (not shown).

In the side channel pump 1 shown by way of example in FIG. 1, the impeller 3 is enclosed by the housing 5 and in particular by the suction cover 15 and the intermediate housing 17. As can be seen in the exploded view of Figure 2, is within the of the suction cover 15 and the

Intermediate housing 17 enclosed space the impeller 3 was added.

Furthermore, remains within this space a free volume through which a Fluid can flow through and which is referred to as pumping chamber 7. The pumping chamber 7 is thereby formed by an inlet-side side channel 31 formed in the suction cover 15, one in the intermediate housing 17

formed outlet side channel 33 and a free volume between the blades 11 of the impeller 3 is formed. With the exception of the area of the pumping chamber 7, walls 19, 21 of the suction lid 15 and the intermediate casing 17 almost directly adjoin corresponding end faces of the impeller 3, possibly being separated therefrom by a narrow gap of e.g. ΙΟΟμηη are spaced.

Fluid to be delivered comes from the inlet 25 and reaches the pumping chamber 7 via an inlet channel 35 which opens into the inlet-side side channel 31. From there, the fluid is distributed via the pumping chamber 7, that is, also into regions between the blades 11 of the rotor 3 and into the

It moves, driven by the rotating impeller 3, along a flow path 39 (see Figure 3), which extends from the inlet channel 35 to an outlet channel 37. The fluid flows partially through the inlet-side side channel 31, partially through the outlet-side flow channel 33 and is partially entrained by the blades 11 of the impeller. In this case, the fluid circulates in a spiral-like movement between the individual subregions of the pumping chamber 7. The fluid which is pressurized leaves the pumping chamber 7 through the outlet channel 37, flows through in the example shown in FIG

Electric motor 13 and then leaves the housing 5 through the outlet 27th

As can be seen in the plan view of FIG. 3, the inlet-side side channel 31 formed in the suction cover 15 extends from the inlet channel 35 in an annular manner along the flow path 39 in a partial circle of about 300 ° up to a region 41 on which it is located in the opposite intermediate housing 17 the local outlet-side side channel 33 leads into the outlet channel 37. He passes a vent hole 43.

In Figure 4, the configuration of a suction cover 15, a

Intermediate housing 17 and the incorporated therein impeller 3 shown in the case of a conventional side channel pump. FIG. 5 shows a corresponding configuration for a side channel pump according to a

Embodiment of the present invention.

In the conventional pump of Figure 4, the inlet side

Side channel 31 and the outlet side side channel 33 with the same widths B and the same depths KTi, KT ₂ dimensioned and thus have the same cross-section with otherwise identical shape.

Although the two side channels 31, 33 are thus formed symmetrically with respect to a plane through the center of the impeller 3, it has been observed that a

Force Fi, which is exerted on the impeller 3 due to the pressure built up in the inlet side channel 31, is smaller than a force F ₂ due to the presence in the outlet side channel 33

constructive pressure is exerted on the impeller 3 in the opposite direction. Since the two oppositely directed forces Fi, F ₂ thus compensate only partially, a resultant force F ₂ -Fi acts on the impeller 3, which presses the impeller 3 toward the inlet-side intake cover 15. The impeller 3 can come into mechanical contact with the suction cover 15, that is without an intermediate gap 23. It can thus come to a solid friction between the impeller 3 and the suction cover 15, which is much stronger than a liquid friction, as occurs, as long as the impeller 3 is spaced by a gap 23 of the suction cover 15 and through the gap, the fluid to be delivered, ie, for example, low-viscosity fuel, can flow.

In the side channel pump 1 according to an embodiment of the present invention, as shown in FIG. 5, the inlet-side side channel 31 and the outlet-side side channel 33 are formed with equal widths B, but have different depths KTi, KT ₂ . Therefore, their cross sections are different and they are with respect to a plane transverse to the side channels

31, 33 and runs centrally through the impeller 3, asymmetric.

For example, the channel depths KTi, KT ₂ may differ from each other by 10% to 25%. For example, the two channel depths KTi, KT _{2 may be} in the range of 1 to 2mm, but the channel depth KTi of the inlet-side channel 31 to be smaller by 0.1 to 0.2 mm than the channel depth KT _{2 of} the outlet-side side channel 33rd

Instead of only the channel depths KJ _lt KT _{2 of} the two side channels 31, 33

In principle, alternatively or additionally, the width and / or shape of the side channels 31, 33 can be selected differently so that the cross-section of the inlet-side side channel 31 is somewhat smaller than that of the outlet-side side channel 33.

It has been observed that by such relative reduction of the

Cross-section of the inlet-side side channel 31 can be achieved that the force Fi, which is exerted due to the building up in the inlet-side side channel 31 pressure on the impeller 3, is approximately equal to a force F ₂ , which due to in the exhaust side Side channel 33 constructive pressure on the impeller 3 is exerted in the opposite direction.

Due to the balance of forces thus balanced on the impeller 3 this is no longer loaded in the axial direction or even shifted. It can thus column 23 between the two end faces and respectively adjacent walls 19, 21 of the suction cover 15 and the intermediate housing 17 can be ensured. The thus given spacing of the impeller 3 from the adjacent walls 19, 21 and the resulting low fluid friction between the end faces of the impeller 3 and these walls 19, 21 can contribute to reduced wear and thus to increased longevity of the side channel pump 1.

Claims

claims

Side channel pump (1), comprising:

a housing (5) enclosing a pumping chamber (7),

an impeller (3) rotatably received within the pumping chamber (7), and within the pumping chamber (7), an inlet-side side channel (31) and an outlet-side side channel (33);

wherein the housing (5) has an inlet channel (35) opening into the inlet-side side channel (31) and one from the outlet side

Side channel (33) discharging outlet channel (37);

wherein the impeller (3) near its outer periphery (9) in one

Blade region has a plurality of radially outwardly extending blades (1 1),

wherein the inlet-side side channel (31) and the outlet-side side channel (33) on opposite sides of the impeller (3) and adjacent to the impeller (3) and wherein the two side channels (31, 33) each along a flow path (39) of the inlet channel (35) extend partially annular to the outlet channel (37),

characterized in that

the inlet side channel (31) averaged along the flow path (39) has a smaller cross section than the outlet side channel (33).

The side channel pump according to claim 1, wherein the inlet side side channel (31) has a smaller cross section at least 50% of the positions along the flow path (39) than the outlet side channel (33) at the same position along the flow path (39).

3. Side channel pump according to claim 1 or 2, wherein the inlet side

Side channel (31) at least 50% of the positions along the

Flow path (39) a smaller by between 5% and 30% Has cross section as the outlet side channel (33) at the same position along the flow path (39).

4. Side channel pump according to one of claims 1 to 3, wherein the

The inlet side channel (31) has a smaller depth at at least 50% of the positions along the flow path (39) than the outlet side channel (33) at the same position along the flow path (39).

The side channel pump of claim 4, wherein the inlet side channel (31) has a depth between 5% and 30% smaller than the outlet side channel (33) at the same position along at least 50% of the positions along the flow path (39) Flow path (39).

6. Fuel pump for a motor vehicle, comprising a side channel pump (1) according to one of claims 1 to 5.