Traitement en cours

Veuillez attendre...

Paramétrages

Paramétrages

Aller à Demande

1. WO1991007593 - PALE A COURBURES MULTIPLES A TRANSITION ABRUPTE ENTRE LES COURBURES

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

Claims

1. A fan comprising an inner hub designed to rotate in a predetermined rotation direction, the hub being attached to blades extending outwardly from the hub to blade tips, the blades being characterized by:
(a) an outer forwardly swept blade region having a leading edge sweep angle θ that is swept in the
predetermined rotational direction at an angle of at least 20°.
(b) a rearwardly swept inner blade in which the leading edge sweep angle θ is swept away from the
predetermined rotational direction;
(c) a transition blade region extending from the outer blade region to the inner blade region, the length of the transition blade region (measured from an outer blade region where θ is at least 20° to an inner blade region that is rearwardly swept so that the leading edge sweep angle θ is -10° or less) is no greater than 0.10R; and
(d) a blade chord which increases with increasing radius in the outer blade region.

2. The fan of claim 1 in which θ changes at least 40° over a radial distance of less than 4% of R.

3. The fan of claim 1 in which θ is at least 30° over a distance of at least 0.05 R in the outer blade region.

4. The fan of claim 1 or claim 3 in which β is -20° or less at a point in the inner blade region which is positioned a distance less than 0.10 R from a point in the outer blade region at which θ is greater than 25°.

5. The fan of claim 1 in which the blade chord increases at least 20% over the range r/R 0.70 to r/R = 0.98.

6. The fan of claim 1 in which θ becomes positive at a point in the transition region where r/R is greater than 0.7.

7. The fan of claim 1 in which β is greater than 40° between r/R = 0.94 and r/R = 0.98, and θ less than -30° between r/R = 0.60 and 0.70.

8. The fan of any one of claim 1-7 further comprising a rotating tip band.

9. The fan of any one of claims 1-6 further comprising means to mount said fan adjacent a heat exchanger.