EP2677175A1 - Multi-stage radial fan - Google Patents

Abstract

The compressor has partial-helical rotor blades radially outward extending between an impeller cover and a circular impeller bottom of an air inlet aperture. The air inlet aperture is centrally arranged in the impeller bottom. An impeller chamber is arranged downstream in an impeller chamber in a fluidic manner. A torque-proof reconducting blading is connected with the impeller chamber. The reconducting blading is partly closed and comprises a reconducting shovel (7), which is formed identical to the rotor blades of an impeller of the impeller chamber.

Description

The present invention relates to a multi-stage radial fan, in particular a multi-stage miniature radial fan.

Radial blowers are known from the prior art. Such or its components are used for example in the EP 1 013 938 B1 disclosed. From the basic structure similar concepts are known in the art as centrifugal pumps, such as from the DE 100 33 402 A1 , However, such centrifugal pumps are not radial fans, as they are not designed to convey gases, but liquids. This requires different designs, designs and designs. It is also known from the prior art to design centrifugal pumps in several stages. It is also known to provide return blades for charging the second and following stages. These are in centrifugal pumps in the prior art, such as in the DE 100 33 402 A1 mostly open. These recirculation loads are designed to utilize the swirl of the fluid to charge the subsequent stages more effectively.

Object of the present invention is to provide a radial fan as shown in EP 1 013 938 B1 known to develop so forth that higher pressure differences can be achieved with high efficiency. For this purpose, the inventor has initially made efforts to increase the speed of the fan accordingly. This did not lead to the desired result. The object is achieved according to claim 1 by a Rückführbeschaufelung, which is at least partially closed and has return vanes, which are identical to the impeller blades of the impeller of the respective impeller chamber formed. The dependent claims 2 to 10 indicate advantageous developments.

According to the invention, the radial fan has at least two impeller chambers which are circular in cross-section and flow-connected one after the other as well as geometrically concentrically arranged. Each impeller chamber of the at least two impeller chambers has an impeller. This has a circular lid and a circular bottom, which are arranged concentrically to one another and to the impeller chamber. In the bottom of an air inlet opening is arranged centrally. In addition, the impeller on a plurality of part spiral impeller blades, as for example from EP 1 013 938 B1 is known. Thus, it is an at least partially closed impeller. The impeller blades extend between the lid and bottom of the air inlet opening radially outward. In this case, according to the invention, at least one impeller chamber, which is connected downstream of at least one further impeller chamber in terms of flow, has a return blading connected in a rotationally fixed manner to the impeller chamber. In this case, the return blading is at least partially closed according to the invention and has return blades, which are formed identically to the impeller blades of the impeller of the impeller chamber.

By such a return blading in at least one impeller chamber, which is downstream of at least one further impeller chamber, the efficiency can be significantly increased, in particular when using the radial fan to achieve high pressure differences.

Such return blading differs from known centrifugal pumps by the formation of the return blading according to the impeller blades. As a result, optimal utilization of the twist and a particularly efficient charging or deflection into the subsequent stage can be achieved.

For this purpose, the Rückführbeschaufelung according to claim 2 advantageously on a centric air outlet, which is fluidly connected to the air inlet of the impeller of the fluidically downstream impeller chamber. In the context of this air outlet or shortly before or after a deflection of the amount of gas to be transported is effected by 90 ° advantageously.

Advantageously, the radial fan is a miniature radial fan.

Advantageously, the diameter of the wheels impeller chambers, and / or Rückführbeschaufelung (s) 3 to 10 cm, in particular 4 to 8 cm, in particular 5 to 7 cm.

Advantageously, the radial fan according to claim 3, in particular characterized in that the return vanes are formed in their number, shape, longitudinal sectional shape and / or relative arrangement to each other and / or in cross section of the impeller identical to the impeller blades of the impeller of the impeller chamber.

It is therefore not important that as a return blading with respect to the blades completely equivalent replica of the impeller of the impeller chamber is used, although this is advantageous. It is also possible, for example, to design the return blading alone with respect to its longitudinal sectional form or its relative arrangement with respect to one another or with respect to the arrangement in cross-section of the impeller chamber with the impeller blades.

Particularly preferred is a conformity with the impeller blades in terms of the number, the longitudinal sectional shape and the relative arrangement to one another and the arrangement in the cross section of the impeller chamber.

In particular, the coincidence in the height of the return vanes with that of the impeller blades is of minor importance and, in particular, depending on the purpose, deliberately deviating from the height of the impeller blades are selected to effect a corresponding pressure adjustment.

Advantageously, the return blading according to claim 4 viewed from the radially inner to the radially outer initially a closed and then open to the impeller of the same impeller chamber area. By such, at least to the impeller of the same chamber open area, a particularly efficient introduction to the return blading can be ensured.

In particular, the impeller chamber is designed so that it has in the longitudinal step parallel to the axis of the concentric arrangement at the ends of a semicircular termination on the side facing away from the wheel, the impeller facing away from the Rückführbeschaufelung starts and facing away from the Rückführbeschaufelung on the impeller facing area End of the impeller is arranged. Also, a shape may be selected with up and down quarter-circle terminations with a straight line portion therebetween. In this case, the impeller is advantageously arranged with respect to the semicircular end or the quarter-circle end in such a way that the end of the impeller blades facing away from the return blading ends with the semicircular or quarter-circle rounding. This results radially outwardly of the impeller and the Rückführbeschaufelung a semi-circular in section, possibly elongated space which extends radially to the Rückführbeschaufelung and the impeller and thus allows optimal transfer of gas from the impeller in the Rückführbeschaufelung.

Advantageously, the return blading is closed according to claim 5 in the area facing away from the impeller of the same impeller chamber to the impeller of the same impeller chamber area. This also supports the most efficient possible continuation of the gas quantities in the subsequent stages.

Advantageously, the impeller in the chamber with Rückführbeschaufelung or has the Rückführbeschaufelung according to claim 6 each 19 blades.

Also preferred is a number of blades of 17 to 21 blades per impeller or return blading.

Advantageously, all impellers and / or Rückführbeschaufelungen the radial fan are identical. With particular advantage, apart from the fluidically last impeller chamber of claim 8 all impeller chambers on a closed Rückführbeschaufelung with identical to the respective impeller blades of the impeller of the respective impeller chamber formed on the return vanes. In this case, with respect to the identity of the blades with respect to claim 3 is executed.

Advantageously, the return vanes, taking into account the features of the respective preceding claims, are designed such that the cross sections between the return vanes used to guide the gas masses initially increase from radially inner to radially outer and then remain constant or smaller, wherein the rising portion advantageously has two-thirds of the radial extent of the return vanes and the change in the cross-sections is effected by longitudinally sectioned by the vanes over the radius of different thickness return vanes.

Such a design of the return blading and also the impeller blades, a particularly efficient promotion of gas quantities can be effected.

With particular advantage, the return vanes are designed so that their return vane outlet angle 55 ° to 80 ° and their return vane inlet angle 15 ° to 35 °. The return bucket exit angle is the angle of the tangent to a return bucket in the radially innermost. The return bucket exit angle is the angle of the tangent at the radially outermost point of the return bucket. In this case, the angle is measured in each case against the tangent of a virtual circle at this point about the axis of concentricity of the impeller chamber.

Fig. 1

eine Ansicht einer Rückführbeschaufelung;

Fig. 2

einen Querschnitt durch eine Rückführbeschaufelung;

Fig. 3

einen Längsschnitt durch ein Radialgebläse; und

Fig. 4

einen Querschnitt durch eine Rückführbeschaufelung.

Further advantageous embodiments and advantages are to be shown purely by way of example and not by way of limitation with reference to the following description of the purely schematic sketches. The figures show in detail:

Fig. 1

a view of a return blading;

Fig. 2

a cross section through a return blading;

Fig. 3

a longitudinal section through a radial fan; and

Fig. 4

a cross section through a return blading.

Fig. 1 Figure 11 shows a plan view of a return blading 9. Recognizable are return blades 7 disposed between a return blading tray 10 and a return blading lid 11. It will be appreciated that the return blading 9 is closed in the area of the return blading tray 10 and in the area where the return blading tray 10 is not disposed is open on one side. Evident are also the part-spiral ends of the return blades 7, which are beyond the Rückkehrbeschaufelungsboden 10 addition.

Fig. 2 shows a cross section through a return blading. Recirculating buckets 7 can be seen in longitudinal section 20. They are formed in part spiral shape on a Rückführbeschaufelungsdeckel 11. This has an air outlet 21. This is arranged centrally.

Fig. 3 shows a longitudinal section through a radial fan. Evident are a first impeller chamber 6 and a second impeller chamber 12. In the first impeller chamber 6, a first impeller 1 is arranged. In the second impeller chamber 12 is a second impeller 13. The impellers have between the impeller bottom 4 and impeller cover 5 impeller blades 3. The impeller floors 4 have air inlet openings 2. The impeller chambers 6, 12 are formed by a surrounding plastic housing. In the first impeller chamber 6, a return blading 9 is arranged in addition to the first impeller 1. This is partially open and partially closed. In addition to a return blading lid 11 and a return blading tray 10, it has return blades 7 disposed between the return blading lid 11 and return blading tray 10 but also extending beyond the extent of the return blading tray 10. The first impeller chamber 6 has at the outer ends in this longitudinal section an air space, which is formed from two quarter-circular sections with a rectangular, straight section arranged therebetween. One Such with two quarter-circular sections up and down limited air space ensures a particularly good transfer of the amounts of gas to be delivered. In particular, this is the case when the quarter-circle boundaries coincide on one side with the end of the impeller blades 3 remote from the return blading on the other end with the ends of the return blades 7 facing away from the impeller. Furthermore, it can be seen that the return blading 9 includes a deflection 8 and an air outlet 21. This air outlet 21 is fluidically coupled directly to the air inlet 2 of the second impeller 13. The impeller blades 3 of the first impeller 1 have in their longitudinal sectional shape, arrangement and number identity with the return blades 7 of the return blading 9 of the first impeller chamber 6.

The wheels 1 and 13 are connected via the drive shaft 15 directly to the drive 16 and thereby can be compared to the impeller chambers 6, 12 and the Rückführgeschaufelung 9, which is rotatably connected to the housing, brought into rotation.

Fig. 4 shows a cross section through a Rückführbeschaufelung, as well as in Fig. 2 shown. Here, however, the return vane entry angles 18 and the return vane exit angles 17 are indicated. In addition, cross sections 19 are marked, which initially increase from the radial interior to the radial outward and then fall off again. In the example shown, the radial inner part of the drawn cross-sections 19 is 3.2 mm on average, the following 3.5 mm of the following radially outwardly adjoining 3, 4.5 mm and the radially outermost drawn 3.2 mm.

In addition, it can be seen that the return vanes 7 have different thicknesses in their longitudinal section 20 over the radius and thus cause just the change of the cross section 19.

reference numeral

1

First impeller

2

Air inlet opening

3

impeller blade

4

rotor base

5

impeller cover

6

first impeller chamber

7

Return blade

8th

redirection

9

return blading

10

Rückführbeschaufelungsboden

11

Rückführbeschaufelungsdeckel

12

Second impeller chamber

13

Second impeller

14

casing

15

drive shaft

16

drive

17

Return blade exit angle

18

Return blade entry angle

19

cross sections

20

Return blade longitudinal section

21

air outlet

Claims (10)

Radial fan comprising at least two circular cross-section fluidly behind one another and geometrically concentrically arranged impeller chambers (6,12) comprising
each an impeller (1, 13) comprising a circular impeller cover (5) and a circular impeller base (4) which are arranged concentrically to one another and to the impeller chamber (6, 12),
a in the impeller bottom (4) centrally arranged air inlet opening (2) and
a plurality of part-spiral impeller blades (3),
which extend radially outward between the impeller cover (5) and impeller bottom (4) from the air inlet opening (2),
at least in one impeller chamber (6),
the fluidically at least one further impeller chamber (12) is connected downstream,
a feedback blading (9) connected rotationally fixed to the impeller chamber (6),
characterized in that
the return blading (9) is at least partially closed and has return vanes (7) which are identical to the impeller vanes (3) of the impeller (1) of the impeller chamber (6). Radial fan according to claim 1, characterized in that the Rückführbeschauflung (9) has a centric air outlet (21), which is fluidically connected to the air inlet opening (2) of the impeller (13) of the fluidically downstream impeller chamber (12). Radial fan according to one of the preceding claims, characterized in that the return vanes (7) in their number, shape, longitudinal section shape (20) and / or relative arrangement to each other and / or in the Cross section of the impeller chamber identical to the impeller blades (3) of the impeller (1) of the impeller chamber (6) are formed. Radial fan according to one of the preceding claims, characterized in that the Rückführbeschauflung (9) viewed from the radially inner to the radially outer initially has a closed and then an open to the impeller of the same impeller chamber area. Radial fan according to the preceding claim 4, characterized in that the Rückführbeschauflung (9) is closed in the direction of the impeller of the same impeller chamber towards the area facing away from the impeller of the same impeller chamber area. Radial fan according to one of the preceding claims, characterized in that the impeller and / or the Rückführbeschauflung in the at least one impeller chamber with Rückführbeschauflung ninteen blade / have. Radial fan according to one of the preceding claims, characterized in that all wheels and / or Rückführbeschauflungen the miniature blower are made identical. Radial fan according to one of the preceding claims, characterized in that, apart from the fluidically last impeller chamber all impeller chambers have a closed Rückführbeschaufelung with identical to the impeller blades of the impeller of the respective impeller chamber formed return vanes. Radial fan according to one of the preceding claims, characterized in that the cross sections (19) between the return vanes (7) viewed through the radius of different thickness return vanes (7) from the radially inner to the radially outer first increases and then remains constant or smaller, wherein the rising region advantageously has two-thirds of the radial extent of the return vanes (7). Radial fan according to one of the preceding claims, characterized in that the return vane exit angle 55 ° to 80 ° and / or the return vane inlet angle 15 ° to 35 °.

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