EP2228541B1 - Rotor for a rotary pump - Google Patents

Description

The invention relates to an impeller for a centrifugal pump according to the features specified in the preamble of claim 1, from the document DE 41 392 293 is known.

Such wheels consist at least of a support body, typically a support plate and arranged thereon blades. The support disk is regularly designed for rotationally fixed arrangement on a shaft. The impeller blades are exposed depending on the design (open impeller) or covered by a cover plate, which is opposite to the support plate and connected to the blades. Such wheels are known in a variety of designs and are used in single or multi-stage centrifugal pumps, they typically have two or more impeller blades, which may be the same or different and / or arranged.

In plastic wheels formed by injection molding, for each change on the impeller usually a separate tool is required. However, blades of different arrangement and size may be provided on an impeller without increasing manufacturing costs. On the other hand, if the impeller, as is the case with a large number of centrifugal pumps, is formed from sheets, typically made of stainless steel sheets, then different tools are required for different blade shapes, which increases the production costs. The production itself takes place in that aligned on the support plate, the individual blades, arranged and then welded to this, after which, if necessary, the cover plate is placed and also welded to the blades.

To cover a variety of applications, centrifugal pumps are available in different sizes. However, the size variance is varied not only by changing the geometrical dimensions and driving power, but also by variance of the blades. If z. As an impeller, which promotes a certain pressure at a certain pressure, should be designed in terms of a reduced flow, so for example, the blade height can be reduced accordingly. However, there are natural limits, as within the impeller a minimum passage height must be maintained to ensure trouble-free operation. For cast wheels, it is state of the art to fill spaces between pairs of blades to reduce the flow rate. For impellers made of sheet metal this is not possible or only with increased effort by two blades are arranged to form a dead space. For each of these blades, however, a separate punching tool is required.

Against this background, the invention is based on the object, manufacturing technology favorable impeller variance, d. H. To create wheels with different funding characteristics that are possible cost, especially made of sheet metal.

This object is achieved according to the invention by an impeller having the features specified in claim 1. Advantageous embodiments of the invention are specified in the subclaims, the following description and the drawing.

The impeller according to the invention for a centrifugal pump has a support disk with blades arranged thereon, in which blades are arranged in pairs next to one another and at least one Shovel pair forming blades have the same shape and size.

The basic idea of the present invention is to provide at least one, preferably a plurality of blade pairs on the impeller, which are each arranged next to each other and have the same shape and size. In this case, these blades preferably have the same shape and size in the final product. However, according to the invention, it is also conceivable to use these blades of the same shape and size only in an intermediate step and, if necessary, to change the shape and / or size in a further processing step. In any case, the fundamental idea is to reduce the variance of the blade shape, so that the number of tools for producing the blades can be reduced and, moreover, the feeding of the blades in the production process and their handling is simplified. Advantageously, the shape and size of such pairs of blades are identical, d. H. they have the same dimensions and the same radii of curvature.

According to the invention, a pair of blades forms a flow-effective blade. So it can be formed with two blades of the same shape hydraulically different effective blades on the impeller solely by arranging the blades. The shape of the blade of such a blade pair according to the invention is typically designed as used in a normal impeller. The achievable by the paired arrangement of identical wheels according to the invention variance is then used for special purposes.

Thus, for example, to increase the length of a blade according to the invention, such an elongate blade can be formed by two blades of a pair of blades which are telescoped to each other. Such an extended blade can, for example, for a support disc larger diameter are used when an impeller is to be designed to achieve a higher head.

As explained at the outset by way of example, it also happens in practice that an impeller is to be designed to produce a lower delivery rate. Then, according to the invention, a blade pair consisting of two blades of the same shape and size can be arranged and aligned such that a dead space forms therebetween fluidically, namely if the radially inner end of one blade bears against the other blade and the radially outer ends are spaced apart, It is understood that a required plurality of such impeller pairs can be arranged on a support disk and that the dead space thus formed is particularly effective when the impeller has a covering cover disk.

In principle, such a dead space can also be formed in another way by a pair of vanes of blades of the same shape and size, for example, when the radially outer ends abut each other and the inner ends are spaced apart, which, however, should generally be less favorable.

In principle, the present invention can be applied to open or covered wheels, particularly advantageous for wheels having a covering shroud.

According to a development of the invention, the blades of a blade pair can be positioned such that a blade of the blade pair protrudes radially beyond the support and / or cover disk. This results hydraulically different effective blades. possibly in a further manufacturing step, the protruding ends can be removed or left so.

It is particularly advantageous in terms of production technology if all the blades have the same shape and size, because then only one tool is needed to produce the blades.

In particular, for wheels with shroud an impeller blade is advantageously dimensioned so that it has a constant height over its entire length. This is particularly advantageous for the pairwise arrangement, since dead spaces can be created particularly well or longer blades can be formed.

The invention is particularly advantageous applicable to wheels that are made of sheet metal, in which so support and / or cover plate and the blades are formed of sheet metal and joined together by welding. Basically, however, the invention is not limited thereto. It is also advantageously applicable to wheels made of other materials, such as plastics or composite materials, in particular when support disk, shroud and blades are made independently and then joined.

Fig. 1

in stark vereinfachter, schematischer, perspektivischer Darstellung ein Kreiselpumpenlaufrad,

Fig. 2

eine Draufsicht auf ein Laufrad ohne Deckscheibe,

Fig. 3

ein erstes Ausführungsbeispiel gemäß der Erfindung in Darstellung nach Fig. 2,

Fig.4

ein zweites Ausführungsbeispiel gemäß der Erfindung in Darstellung nach Fig. 2,

Fig. 5

ein drittes Ausführungsbeispiel in Darstellung gemäß Fig. 2 und

Fig. 6

eine Weiterbildung des Ausführungsbeispiels gemäß Fig. 5 in Darstellung noch Fig. 2.

The invention is explained below with reference to exemplary embodiments which are illustrated in the drawing. Show it:

Fig. 1

in a highly simplified, schematic, perspective view of a centrifugal pump impeller,

Fig. 2

a plan view of an impeller without cover plate,

Fig. 3

a first embodiment according to the invention in illustration according to Fig. 2 .

Figure 4

A second embodiment according to the invention in illustration according to Fig. 2 .

Fig. 5

a third embodiment in illustration according to Fig. 2 and

Fig. 6

a development of the embodiment according to Fig. 5 in representation yet Fig. 2 ,

This in Fig. 1 shown impeller has a circular support plate 1, which has a central recess 2, which is profiled and is provided for non-rotatable connection with a drive shaft, not shown, as counts in centrifugal pumps of the prior art. On the support disk 1, a plurality of impeller blades 3 is arranged, which extend at a distance from the recess 2 to the outer periphery of the support disk 1. The blades 3 are covered on the opposite side of the support disk 1 by a cover plate 4, which in the embodiment according to Fig. 1 on the inside in an annular portion 5 opens, which forms the inlet of the impeller, as is known per se and therefore will not be described in detail here.

When the cover plate 4 is removed, the shape and arrangement of the blades 3 can be seen, as shown in FIG Fig. 2 is shown by way of example. This impeller according Fig. 2 has a total of six blades 3, which have the same shape and size and are arranged at the same angular distance on the support disk 1.

To such an impeller, as it is based on the FIGS. 1 and 2 is designed to be designed for lower flow rates are in the impeller according to Fig. 3 in each case two blades 3a and 3b are arranged to form a pair of blades such that a dead space 6 is hydraulically arranged between them forms. The blades 3a and 3b are of the same shape and size, ie they have the same length, the same height and the same radius of curvature for the same material thickness. However, they are arranged differently. The blades 3a are arranged in the same way as those in the impeller according to Fig. 2 , However, in addition to the blades 3 and 3a, blades 3b are arranged such that the radially inner end 7 of a blade 3b abuts the inside of a blade 3a, whereas the radially outer ends 8 of the blades 3a and 3b are spaced apart.

In the execution according to Fig. 4 are on the support plate 1 also six blade pairs, each consisting of the blades 3a and 3b, arranged, but not to form a dead space, but to form longer blades. In each case, the blades 3a and 3b are applied to each other in pairs and pulled apart telescopically, so that in comparison to the individual blades 3a and 3b from each pair of blades a single hydraulically effective blade, but longer length results.

In the third embodiment according to Fig. 5 are also six pairs of blades each consisting of the blades 3a and 3b arranged on a support disk 1. However, the vanes 3a are arranged radially further inward so that their radially outer ends terminate with the outer circumference of the support disk 1, whereas the outer ends of the vanes 3b protrude beyond this outer circumference. In addition, the blades 3a and 3b are arranged at different angles to each other.

In all the embodiments described above, the pairs of blades 3a and 3b arranged on the support disk 1 are identical in shape and size, ie they have the same length, the same height and the same radius of curvature. That way you can get wheels different hydraulic properties can be produced using the same shape components, which is advantageous, since one and the same punching tool can be used for the blades 3 and 3a and 3b. It is understood that this is not mandatory. It can also be arranged under pairwise arrangement of the same shape blades 3a and 3b on a wheel different blade pairs or other other blades, if this is advantageous or appropriate.

The according to Fig. 5 illustrated and above impeller may optionally be processed in a further processing step, such that the protruding ends of the blades 3b are removed, then the resulting pairs of blades, consisting of the blades 3b 'and 3a, are no longer form-and after this processing step size the same.

LIST OF REFERENCE NUMBERS

1 -

carrying disc

2 -

recess

3 -

shovel

3a -

a shovel of a pair of shovels

3b -

other shovel of a pair of shovels

4 -

cover disc

5 -

annular section

6 -

dead space

7 -

inner end of a shovel

8th -

outer end of a shovel

3b '-

cut off scoop

Claims (9)

1. An impeller for a centrifugal pump with a carrier disk (1) and blades (3) arranged thereon, with which blades (3) are arranged next to one another in pairs, wherein a blade pair forms a flow-effective blade (3a, 3b), characterised in that at least the blades (3a, 3b) forming a blade pair have the same shape and size.
2. An impeller according to claim 1, characterised in that the blades (3a, 3b) of a blade pair bear on one another in a telescopic manner.
3. An impeller according to one of the preceding claims, characterised in that the blades (3a, 3b) of a blade pair form a dead space (6).
4. An impeller according to one of the preceding claims, characterised in that the blades (3a, 3b) of a blade pair which form a dead space (6) are distanced at their radially outer ends (8), and the radially inner end (7) of a blade (3b) bears on the other blade (3a).
5. An impeller according to one of the preceding claims, characterised in that a shroud (4) covering the impeller is provided.
6. An impeller according to one of the preceding claims, characterised in that the impellers (3a, 3b) of a blade pair are positioned in a manner such that a blade (3b) of a blade pair projects radially beyond the carrier disk and/or the shroud (1, 4).
7. An impeller according to one of the preceding claims, characterised in that all blades (3a, 3b) have the same shape and size.
8. An impeller according to one of the preceding claims, characterised in that a blade (3) has a constant height over its radial length.
9. An impeller according to one of the preceding claims, characterised in that the carrier disk and/or shroud (1, 4) and the blades (3) are formed of metal, preferably of sheet metal, and are connected to one another by way of welding.

Images