Diagonal fan wheel with increased strength

Abstract

A diagonal fan wheel (1) has a cover disk (2) and a bottom disk (3). A plurality of three-dimensionally curved blades (S) are arranged between the cover disk (2) and bottom disk (3). The blades (S) are connected to the cover disk (2) and bottom disk (3) in a materially bonded manner.

Claims

1. A diagonal fan wheel comprising: a cover disk and a bottom disk both radially extending outwardly from an axis of the diagonal fan, at least one of the cover disk and bottom disk including a wall construction portion, the wall construction portion extending axially along the axis of the diagonal fan, the wall construction portion including a multitude of elongated hollow chambers that extend axially in the wall construction portion; multiple three-dimensionally curved blades are disposed or extend between the cover disk and the bottom disk; the curved blades are connected to the bottom disk and the cover disk in a materially bonded manner.

2. The diagonal fan wheel according to claim 1, wherein the diagonal fan wheel is designed both integrally and in one part.

3. The diagonal fan wheel according to claim 1, wherein the cover disk of the fan wheel is formed in a specific shape comprising a cylindrical contour adjoined by a conical section and a transition from the cylindrical section into the conical section is not discrete, but transitions continuously via a curved contour having a predetermined radius R.

4. The diagonal fan wheel according to claim 1, wherein the bottom disk is substantially conical and forms a conical region.

5. The diagonal fan wheel according to claim 1, wherein the impeller is configured such that a differential angle of a tangent placed on a respective upper surface of the cover and bottom disks between the cover and the bottom disks is at least >1° (greater than 1°) in the conical regions.

6. The diagonal fan wheel according to claim 1, wherein an edge on a blade front edge on a pressure side of a respective curved blade is configured as a sharp edge, in a transition from the pressure side to a suction side of the curved blade is rounded or formed with a rounded edge region.

7. The diagonal fan wheel according to claim 1, wherein an inner surface of the cover disk is configured drawn towards the bottom disk at a blade attachment such that a drawn nose projects from an edge, the edge otherwise extending on a circular line formed on the edge.

8. The diagonal fan wheel according to claim 1, wherein an outer contour of the cover disk is rotationally symmetrical.

9. The diagonal fan wheel according to claim 1, wherein the curved blades have a specific continuously changing wall thickness distribution in their three-dimensionally curved extension.

10. A diagonal fan wheel comprising: a cover disk and a bottom disk, at least one of the cover disk and bottom disk including a wall construction portion extending axially with respect to an axis of the diagonal fan, the wall construction portion has a multitude of axially extending elongated hollow chambers in the wall construction; multiple three-dimensionally curved blades are disposed or extend between the cover disk and the bottom disk; the curved blades are connected to the bottom disk and the cover disk in a materially bonded manner.

Description

DRAWINGS

(1) FIG. 1 is a perspective view of an exemplary embodiment of a diagonal fan wheel;

(2) FIG. 2 is a perspective view of the diagonal fan wheel from FIG. 1;

(3) FIG. 3 is a graph representing the connection between the maximum material thickness of the blade viewed in the flow direction along the blade from the bottom disk to the cover disk; and

(4) FIG. 4 is a perspective bottom view of the diagonal fan wheel, representing positions between which the maximum material strength changes.

DETAILED DESCRIPTION

(5) The disclosure is described below with reference to an exemplary embodiment and to FIGS. 1 to 4. The same reference symbols indicate the same functional and/or structural features.

(6) FIG. 1 is a perspective view of an exemplary embodiment of a diagonal fan wheel 1. The cover disk 2 of the fan wheel 1 is formed in a specific shape, namely, as a cylindrical contour 20 in the upper region. This cylindrical region 20 subsequently transitions into an adjoining conical section 22. The transition 21 from the cylindrical section 20 to the conical section 22 is not discrete. The transition section 21, transitions continuously via a curved contour having a specific radius R. The hat-like shape formed in this manner is designed such that the conical section extends from a joining region (radius R) from the transition from the cylindrical section 20 into the conical section 22 down to a bottom edge 24. This defines an imagined plane. The plane extends below an imagined plane through an upper edge region of the bottom disk. Thus, there is an overlap region with an intermediate space therebetween where the blades S extend from the outer surface of the bottom disk 3 to the inner surface of the cover disk 2.

(7) As is further visible in FIG. 1, the cylindrical section 20 can be formed by a wall construction where a multitude of hollow chambers are provided.

(8) It can further be seen in FIG. 1 that the bottom disk 3 of the impeller 1 is substantially conical. Thus, it forms a conical region 30. A cylindrical region, like the cover disk 2 can also be formed from a wall construction where a multitude of hollow chambers are provided, adjoins the conical region of the bottom disk 3.

(9) The impeller 1 is designed such that a differential angle (of the tangents placed on the conical section) between the cover and bottom disks 2, 3 is at least >1°, preferably >2° in the conical regions 22, 30. This means that the angle of attack of the conical region of the cover disk 22 differs by at least 1° with respect to the angle of attack of the conical region 30 of the bottom disk 3. Advantageously, the angle of attack, angle between the tangent placed on the conical region and the central cylindrical axis through the cylindrical region of the cover disk, is greater than the angle of attack of the conical region of the bottom disk. For example, the angle of attack of the cover disk can be between 46° to 60°. The angle of attack of the bottom disk is between 30° and 45°.

(10) The edge K on the blade front edge on the pressure side of the blade S is configured as a sharp edge. The transition R from the pressure side to the suction side of the blade S is rounded (formed with a radius R) (see the details in FIG. 1).

(11) The inner surface of the cover disk 2 at the blade attachment point 23 is drawn in the direction of the bottom disk 3. Thus, a drawn nose projects from the edge 24 that other wise is a circular line. This increases the strength and reduce turbulences. The outer contour remains rotationally symmetrical, as can be seen in the view of FIG. 2. The noses may alternatively be disposed at discrete positions along the edge 24. The noses are shaped such that their cover surfaces, upper surfaces, are formed as extensions of the conical cover disk. Thus, they have the same angle of attack as the cover disk. This means that the tangent on the surface of the cover disk also extend as a tangent in the region of the nose.

(12) The contour of the edge 24 in the region of the nose(s) corresponds to a Gaussian distribution curve. The flanks extend asymptotically and continuously into the edge 24 (that is, without a kink) or sudden change.

(13) The blades S have a specific continuously changing wall thickness distribution over their three-dimensional extension. The distribution is shown in FIG. 3. The wall thickness distribution between the positions P=0 (attachment to the bottom disk 3) and P=1 (attachment to the cover disk 2) increases the strength of the radial fan wheel 1. The maximum wall thickness is about 3.4 mm in the attachment region on the bottom disk 3. It continuously decreases in a non-linear manner towards the cover disk 2. The maximum thickness is approx. 2 mm at the cover disk 2.

(14) It is preferred that the wall thickness distribution is detected on the outer, i.e. exterior edge and can decrease differently in the region closer to the center (due to the different spacings between the bottom disk and the cover disk). But in principle, the wall thickness of the respective blade S decreases from the bottom disk towards the cover disk. It is also conceivable that one or more blades each have a different wall thickness distribution, wherein a rotationally symmetrical design must be retained.

(15) The implementation of the disclosure is not limited to the preferred embodiments described above. Instead, a plurality of variants is conceivable where the solution described is used for completely different designs.

(16) The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.