Patent Application
20140023516
This application claims priority of German Patent Application No. 10 2012 106 412.1 filed Jul. 17, 2012, which is hereby fully incorporated herein by reference.
The invention relates to a diagonal impeller for a diagonal fan, and to a diagonal fan for gaseous media.
A diagonal impeller for a diagonal fan is known from DE 10 2010 032 168 A1. Such fans can convey a flow medium consisting of air or other gases from inside to outside. Fans of this type can be used for example at the start, within, or at the end of pipelines, wherein the use is not limited to the use of pipeline systems. A guide device for increasing the pressure of the flow medium is provided downstream of the diagonal impeller in the diagonal fan. The diagonal impeller consists of a carrier plate with vanes arranged thereon, which extend radially outwardly in the direction of a cover plate. The cover plate is fastened to an inlet nozzle, which is in turn arranged on an outer housing portion on an intake unit. The diagonal impeller is driven by a motor, wherein the motor shaft of said motor carries the carrier plate. The vanes of the diagonal impeller and/or the guide vane of the guide device are three-dimensionally twisted. Improved efficacy compared to two-dimensionally twisted vanes on a carrier plate, as are known for example from U.S. Pat. No. 3,059,833, can thus be achieved. Due to increasingly stricter guidelines on energy conservation, it is necessary to further develop diagonal impellers of this type for diagonal fans, as well as diagonal fans.
The object of the invention is to create a diagonal impeller and a diagonal fan comprising such a diagonal impeller, with which an increased energy saving is made possible.
This object is achieved both by the independent claim relating to the diagonal impeller and by the independent claim relating to the diagonal fan. Further advantageous embodiments and developments are disclosed in the other claims.
With the diagonal impeller according to the invention a leading corner region, formed by a leading edge and an outer edge, of the vane is inclined in an increased manner in the direction of rotation relative to the adjoining vane face. Furthermore, an outer trailing corner region formed between the trailing edge and the outer edge may alternatively be inclined in an increased manner against the direction of inflow. A curved leading corner region and trailing corner region may also be provided on a vane. Due to this increased curvature of the outer leading corner region in the direction of rotation and/or of the outer trailing corner region against the direction of rotation, an increased build-up of pressure can be obtained with constant driving power of the motor and flow losses can be minimised, such that an optimised airflow is formed. An increase in efficiency can thus be achieved.
In accordance with a preferred embodiment of the vane geometry, the outer leading corner region is inclined over a region of less than a quarter of the length of the leading edge and the length of the outer edge. Only the outermost corner region is thus inclined or curved more greatly in the direction of rotation, wherein the inclination over the outer edge and the leading edge is identical.
In accordance with a further preferred embodiment of the invention, the outer trailing corner region is inclined over a region of less than a quarter of the outer trailing edge. The same advantages as with the leading corner region are therefore obtained.
The curvature of the leading and/or trailing region is preferably provided in such a way that the leading edge or trailing edge, as viewed in the direction of rotation, is aligned in the respective corner region so as to be practically horizontal or horizontal—that is to say in a plane perpendicular to the axis of rotation.
In accordance with a further preferred embodiment of the vane geometry, the free outer edge extends from the leading edge to the trailing edge in a flat, sinusoidal manner. The flow can thus be guided effectively.
In accordance with a further preferred embodiment of the diagonal impeller, a corner region adjoining the trailing edge and a lateral surface of the carrier plate is curved at said trailing edge in a direction opposite that of the outer trailing corner region. This arrangement enables an increased lifting effect of the flow, whereby an increase in efficiency is in turn achieved.
The object of the invention is also achieved by a diagonal fan, which comprises a diagonal impeller, which comprises a guide device, attached thereto in a downstream direction, to increase the pressure of the flow medium and is surrounded, at least over portions, by a cover plate in the radial direction as well as in the axial direction, an outer leading corner region formed by the leading edge and outer edge being inclined in an increased manner in the direction of rotation and/or an outer trailing corner region formed between the trailing edge and the outer side being inclined in an increased manner against the direction of rotation. Such a diagonal fan enables a further energy saving. Due to such a diagonal impeller in a diagonal fan, the different flow rates and directions of inflow both at the inlet and at the outlet of the vanes can be optimally adapted so as to optimise the fluidic guidance of the air and to increase efficiency.
The invention and further advantageous embodiments and developments thereof will be described and explained in greater detail hereinafter on the basis of the examples illustrated in the drawings. The features to be derived from the description and the drawings can be applied in accordance with the invention either individually or together in any combination. In the drawings:
A schematic sectional illustration of a diagonal fan 11 is illustrated in
The diagonal fan 11 has a diagonal impeller 26, which is assigned on the inflow side to an intake unit 29. On the outflow side of the diagonal impeller 26, a guide device 28 followed by a diffuser 30 are formed inside the diagonal fan 11. The diffuser 30 is formed by a blow-out unit 31. The gaseous flow medium pushed through the diagonal fan 11 by means of the diagonal impeller 26 circulates around a central interior of the diagonal fan 11, which is defined inwardly by a carrier plate 33 of the diagonal impeller 26 and an intermediate casing 34 adjoining the carrier plate 33 aerodynamically. The carrier plate 33 curves on the outflow side in an axial direction, so that it contacts the intermediate casing 34, oriented in the axial direction, aerodynamically. The flow medium therefore flows radially outwardly past the carrier plate 33 and the intermediate casing 34.
The diagonal impeller 26 has peripherally distributed vanes 36, which are fastened on one side to the carrier plate 33. On the opposite side, free vane ends 37 of the vanes 36 point toward a peripheral face 39 of a cover plate 40, which is fastened to the housing portion 12. A gap 43 is formed therebetween between the vane ends 37 of the vanes 36 and the peripheral surface 35 of the cover plate 40. The vanes 34 are profiled cross-sectionally for example and are three-dimensionally twisted. The cover plate 40 may form part of an inlet nozzle 41. Alternatively, the inlet nozzle 41 can be fastened to the housing portion 12 and may engage around or carry the cover plate 40, so that an aerodynamic transition between the intake unit 29 and guide device 28 is provided. If the inlet nozzle 41 and cover plate 40 are each formed separately, an intermediate annular gap is produced, which can be sealed by a seal element. Alternatively, such an annular gap may also be formed as a flow labyrinth.
The flow leaving the diagonal impeller 26 then flows through the region of the guide device 28. In this portion of the diagonal fan 11, peripherally distributed stationary guide vanes 45 are arranged between the intermediate casing 34 and the housing portion 12. The flow leaving in a helical, diagonal direction of the diagonal impeller 26 is deflected in an axial direction of flow by the guide vanes 45. Similarly to the vanes 36 of the diagonal impeller 26, the guide vanes 45 in the present example are also profiled and three-dimensionally twisted. Alternatively, the profiling of the vanes 36 and/or the guide vanes 45 could also be omitted.
A motor 50, which drives the diagonal impeller 26 by means of a driveshaft 51, is located in the interior space 47 formed by the carrier plate 33 of the diagonal impeller 26 or by the intermediate casing 34 of the guide device 28. The motor 50 is flange-mounted on a motor holder, which extends from the intermediate casing 34 into the interior space 47.
After the guide device 28, the diffuser 30 is formed downstream thereof. The diffuser 30 is constructed by an annular flow duct, that increases in a downstream direction, between a motor cover 54 and a housing wall 56 of the blow-out unit 31. The motor cover 54 is fastened to the intermediate casing 34 of the guide device 28 by means of a plurality of screws (not illustrated here) and closes the interior space 47 on the outflow side.
The carrier plate 33 of the diagonal impeller 26 is fastened to the motor 50, in particular to the driveshaft 51, via a fastening element 61. In this embodiment a gap 43 is set between the free vane ends 37 of the diagonal impeller 26 and the peripheral surface 39 of the cover plate 40.
The diagonal impeller 26 is illustrated in perspective view in
The vanes 36 have a leading edge 81 (upstream), which is inclined radially outwardly and upstream relative to the axis of rotation 62. In addition, this leading edge 81 is inclined extending in a straight line and slightly in the direction of rotation. On the opposite side, the vane 36 has a trailing edge 82, which is likewise inclined upstream and extending in a straight line. The vane end 37 is formed between the leading edge 81 and the trailing edge 82 by an outer edge 84, which simultaneously forms a gap 43 between a cover plate 14, associated with the diagonal impeller 26, and the peripheral surface 39 thereof.
In the region of transition between the leading edge 81 and the outer edge 84, an outer leading corner region 86 is formed, which has an increased curvature in the direction of rotation so that it is approximately horizontal, as viewed in the direction of rotation. An outer trailing corner region 88 is formed oppositely between the outer edge 84 and the trailing edge 82 and is curved against the direction of rotation. The trailing corner region 88 is thus curved in a direction opposite that of the leading corner region 86. An outer edge 84, which extends in a flat, sinusoidal manner, is thus produced. The vane areas between the leading edge 81 and the trailing edge 82 as well as between the outer edge 84 and a lateral surface 67 of the carrier plate 33 are three-dimensionally twisted, that is to say they are not developable, wherein the flow rate and the separation behaviour are to be taken into account in a region in the vicinity of the lateral surface and in a radially outer region in the vicinity of the vane ends 37.
The leading corner region 86 and the trailing corner region 88 have a type of spoiler function so as to obtain improved guidance of air into the outer end regions.
In addition, in contrast to a frustum-shaped main body 60, the carrier plate preferably has a bell shape. In this case, at least one S-shaped undulation 70 is preferably provided between a head region 63 and a foot region 68, which are connected by the lateral surface 67, the bell shape being formed with the formation of an S-shaped undulation. Increased contouring of the adjoining vane face of the vane 36 can thus be enabled, in particular in a central region of the lateral surface.
The flow can be optimised as a result of the fact that the outer leading corner regions 86 and trailing corner regions 88 of the vanes 36 are each curved in an increased manner.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2012 106 412.1 | Jul 2012 | DE | national |
