Diagonal fan

Abstract

Diagonal fan having a fan housing, within which an external-rotor motor and an impeller are accommodated, wherein the external-rotor motor has a stator and a rotor which at least partly surrounds the stator, and an axial flow duct runs between the fan housing and the external-rotor motor as far as a discharge opening, surrounding the external-rotor motor, of the diagonal fan, through which duct, during operation, air which is drawn in by means of the impeller can be conveyed to the discharge opening, and wherein the impeller is integrated in the rotor.

Claims

1. A diagonal fan having a fan housing, within which an external-rotor motor and an impeller are accommodated, wherein the external-rotor motor has a stator and a rotor which at least partly surrounds the stator, and an axial flow duct runs between the fan housing and the external-rotor motor as far as a discharge opening, surrounding the external-rotor motor, of the diagonal fan, through which axial flow duct, during operation, air which is drawn in by means of the impeller and is conveyed to the discharge opening, and wherein the impeller is integrated in the rotor, and the impeller and the rotor are designed as a single piece, while an air guide apparatus with several air guide vanes distributed in the circumferential direction is arranged in a discharge portion bordering on the discharge opening, and the air guide vanes extend in the axial direction at least in an overlap portion (Ly) beyond the rotor and are spaced apart from the rotor with a radial air gap, wherein the fan housing is multiple-piece and comprises an inlet nozzle and a discharge piece, while the inlet nozzle has an intake opening and the discharge piece comprises the discharge opening, and wherein the inlet nozzle comprises an inlet portion reducing the flow diameter, which extends in the axial direction into the impeller, and wherein the impeller and/or the air guide vanes are designed such that an axial spacing between the air guide vanes and the impeller increases in the radial direction from a first spacing (A1) to a second spacing (A2), and wherein a radius (R1) of the impeller at a point of attack of the first spacing (A1) is larger than the first spacing (A1), and wherein the impeller comprises impeller vanes and a cover disk, while the impeller vanes extend from the rotor to the cover disk.

2. The diagonal fan as claimed in claim 1, wherein a ratio of the axial length of the overlap portion (Ly) of the air guide vanes to a non-overlapping portion (Lx) in which the air guide vanes do not overlap the rotor in the axial direction lies in a range of 0.5 to 4.0.

3. The diagonal fan as claimed in claim 1 wherein the air guide vanes are fastened for a portion to the fan housing in the axial direction.

4. The diagonal fan as claimed in claim 1, wherein the radial air gap corresponds at most to 5% of a maximum radial installation space of the diagonal fan.

5. The diagonal fan as claimed in claim 1, wherein the inlet nozzle is connected to the discharge piece bordering directly on the discharge piece in the axial direction.

6. The diagonal fan as claimed in claim 5, wherein the cover disk completely overlaps the impeller vanes in the radial direction.

7. The diagonal fan as claimed in claim 1, wherein the discharge opening forms a discharge surface which does not have rotational symmetry.

8. The diagonal fan as claimed in claim 1, wherein the intake opening has an intake diameter corresponding to 40 to 75% of a maximum radial installation space of the diagonal fan.

9. The diagonal fan as claimed in claim 1, wherein the impeller has an impeller diameter which corresponds to 80 to 95% of a maximum radial installation space of the diagonal fan.

10. The diagonal fan as claimed in claim 1, wherein the impeller is situated bordering directly on the axial flow duct and an air flow generated by the impeller is delivered directly into the axial flow duct.

11. The diagonal fan as claimed in claim 1, wherein a ratio of the axial length of the overlap portion (Ly) of the air guide vanes to a non-overlapping portion in which the air guide vanes do not overlap the rotor in the axial direction lies in a range of 1.5 to 2.5.

12. The diagonal fan as claimed in claim 1, wherein the radial air gap corresponds at most to 1.5% of a maximum radial installation space of the diagonal fan.

13. The diagonal fan as claimed in claim 1, wherein the intake opening has an intake diameter corresponding to 50 to 60% of a maximum radial installation space of the diagonal fan.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1, a perspective view of a diagonal fan;

(2) FIG. 2, a front view of the intake side of the diagonal fan of FIG. 1,

(3) FIG. 3, a rear view of the intake side of the diagonal fan of FIG. 1,

(4) FIG. 4, a cross sectional view of the top half of the diagonal fan of FIG. 1.

DETAILED DESCRIPTION

(5) FIGS. 1 to 3 show a sample embodiment of a diagonal fan 1 various views. FIG. 4 is a corresponding longitudinal section view for a more accurate representation of the individual components and their mutual arrangement.

(6) The diagonal fan 1 comprises a two-piece fan housing formed from the inlet nozzle 31, having the inlet opening 3, and the discharge piece 32, having the discharge opening 5, at whose axial ends are formed a respective flange 21, 20. The inlet nozzle 31 is inserted into the discharge piece 32. Centered about the axis of rotation RA is provided the external-rotor motor with the stator 11 and the rotor 9, which covers the stator 11 for a portion in the axial direction.

(7) The impeller of the diagonal fan 1 is formed from the rotor 9, the impeller vanes 8 arranged on it, and a cover disk 24 fully overlapping the impeller vanes in the radial direction, having an end portion running axially straight in the direction of the inlet opening 3. The rotor 9 forms a bottom disk for the impeller. The impeller is thus integrated in the rotor 9. The inlet nozzle 31 comprises an inlet portion 7 reducing the flow diameter, which extends in the axial direction into the impeller, so that the axially parallel end portion of the cover disk 24 and the inlet portion 7 overlap.

(8) Axially bordering on the impeller, the axial flow duct 19 extends between the discharge piece 32 of the fan housing and the rotor 9 of the external-rotor motor as far as the discharge opening 5 surrounding the stator 11.

(9) In a discharge portion bordering on the discharge opening 5 there is situated an air guide apparatus with several air guide vanes 10 distributed in the circumferential direction, which are also clearly seen in FIG. 3. Bordering on the discharge opening 5, the air guide vanes 10 are connected to the stator 11 and to the discharge piece 32. The air guide vanes 10 extend both in the axial direction and also in the circumferential direction. They extend in the axial direction beyond the rotor 9 in the overlap portion Ly and are spaced apart from the latter by a radial air gap S, where the air gap S in the embodiment depicted corresponds to 1% of the maximum radial installation space B of the diagonal fan 1. The size of the air gap S is constant over its axial extension. The ratio of the axial length of the overlap portion Ly of the air guide vanes 10 to the axially bordering non-overlapping portion Lx lies at a value of 2.1 in the embodiment depicted.

(10) Referring in particular to FIG. 4, the spacing between the mutually facing axial edges of the air guide vanes 10 and the impeller vanes 8 increases in a direction, looking radially outward, from a first spacing A1 to a second spacing A2, where the axial edges of the air guide vanes 10 extend straight radially outward, while the impeller vanes 8 are slanted. The position of the first and second spacing can be chosen freely, while the radius R1 of the impeller at the point of attack of the first spacing A1 is larger than the first spacing A1. Moreover, the radius R2 of the impeller at the point of attack of the second spacing A2 is greater than the second spacing A2. The impeller has an impeller diameter corresponding to 90% of the maximum radial installation space B of the diagonal fan 1.