Compact diagonal fan

Abstract

The invention relates to a diagonal fan having a housing, an impeller driven by an electric motor whose hub together with an air conduction sleeve surrounding the impeller defines an essentially annular flow channel having an air intake opening and an air exit opening. The hub takes the form of a truncated cone that widens towards the air exit opening, the air conduction sleeve being essentially profiled, the electric motor being held in the housing by means of bridges that essentially extend in a radially outwards direction. The invention is characterized by the fact that the bridges to secure the motor are arranged in the region of the air intake opening of the flow channel.

Description

BACKGROUND OF THE INVENTION [0001] The invention relates to a compact diagonal fan according to the preamble of patent claim 1. PRIOR ART [0002] At first glance there seems to be very little difference between diagonal fans and the familiar axial fans, which is why they are also frequently referred to as “semi-axial” blowers. Like an axial fan, a diagonal fan according to FIG. 3 essentially comprises a housing 100, an electric motor 101 supported within the housing 100 whose hub 102, together with a plurality of blades 103 formed on the hub 102, go to make up the impeller 104 of the fan. The impeller 104 is rotatably supported about a rotational axis 105 and is driven by the electric motor 101. The electric motor 101 is held within the housing100 by means of bridges 106 which essentially extend in a radially outwards direction. [0003] For both diagonal and axial compact fans, the motor 101, the commutation electronics (if used), the impeller 104 and the housing 100 are all integrate...

AI Technical Summary

Benefits of technology

[0006] The object of the invention is to provide a diagonal fan which has considerably lower operating noise compared to a conventional diagonal fan with the same airflow rate and rise in pressure.

[0009] The invention is characterized by the fact that the bridges used to secure the motor to the housing are arranged in the region of the air intake opening of the flow channel. This makes it possible to fit a larger fan wheel with the overall dimensions of the fan remaining unchanged. A larger fan wheel has a greater air flow so that the fan according to the invention can be operated at a relatively lower rotational speed to achieve the same air flow as a conventional fan. Operating the fan at a lower speed, however, means that the operating noise is also lowered, which was the actual objective of the invention.

[0010] Arranging the bridges in the region of the air intake opening makes it possible to fix the blades of the impeller close to the air exit opening of the flow channel and thus in the region where the diameter of the hub is at its largest so that the overall diameter of the fan wheel is increased.

[0011] The cross-section of the flow channel runs at a sharp angle radially outwards with respect to the rotational axis of the impeller, so that the air flowing through the fan is expelled diagonal to the rotational axis. One way of improving the rise in pressure compared to an axial fan is by decreasing the cross-section of the flow channel in the direction of the air exit opening.

[0012] To reduce the noise of the fan even further, provision is made for the profiled surface of the air conduction sleeve to be rounded off at the air intake opening in a radially outwards direction.

Problems solved by technology

To date, small ventilators are hardly ever found with a diagonal design, which can perhaps be primarily attributed to the complicated geometry of the impeller.

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