Rotor blade and screen comprising a rotor blade

Patent metadata

Field	Value
Publication number	US-10724175-B2
Application number	US-201616073350-A
Country	US
Kind code	B2
Filing date	Nov 15, 2016
Priority date	Feb 3, 2016
Publication date	Jul 28, 2020
Grant date	Jul 28, 2020

Abstract

The invention relates to a blade for screens for the treatment of a fibrous suspension, said blade being mountable on a rotor of the screen. According to the invention, the blade has a curved leading edge or curved envelope of the leading edge, the curvature extending in the direction of the trailing edge, and a curved trailing edge or curved envelope of the trailing edge, said curvature extending in the same direction as the other one. The invention also relates to a screen comprising a rotor on which the disclosed blades are mounted.

First claim

The invention claimed is:

1. A blade ( 10 ) for screens used to treat a fibrous pulp suspension which blade ( 10 ) is configured for attachment to a screen rotor ( 1 ) and where the blade ( 10 ) extends between a leading edge ( 11 ) and a trailing edge ( 12 ) with two opposite end edges ( 17 , 18 ) therebetween and defines an upper side and lower side, the leading edge ( 11 ) or an envelope curve ( 21 ) thereof being arched in a direction ( 23 ) toward the trailing edge ( 12 ), the trailing edge ( 12 ) or the envelope curve ( 22 ) of the trailing edge ( 12 ) being arched in a common direction ( 23 ) relative to the leading edge ( 11 ), wherein the blade ( 10 ) has a cross-section with a wing-shaped profile having a convex upper surface.

2. The blade ( 10 ) according to claim 1 , wherein the leading edge ( 11 ) is curved symmetrically from the middle of the blade ( 24 ) towards its opposite end edges ( 17 , 18 ).

3. The blade ( 10 ) according to claim 2 , wherein the leading edge ( 11 ) or the envelope curve ( 21 ) of the leading edge ( 11 ) is curved in an arc shape.

4. The blade ( 10 ) according to claim 1 , wherein the leading edge ( 11 ) is stepped and an envelope curve ( 21 ) thereof is curved in the direction ( 23 ) of the trailing edge ( 12 ).

5. The blade ( 10 ) according to claim 4 , wherein the trailing edge ( 12 ) is stepped and an envelope curve ( 22 ) thereof is curved.

6. The blade ( 10 ) according to claim 1 , comprising a plurality of bars ( 19 , 20 ) on the upper side of the blade.

7. The blade ( 10 ) according to claim 1 , wherein the angle of the arch of the leading edge ( 11 ) or the envelope curve ( 21 ) thereof is equivalent to the angle of the arch of the trailing edge ( 12 ) or the envelope curve ( 22 ) thereof, and the wing-shaped profile is substantially the same over the entire length of the blade when viewed in cross-section.

8. The blade ( 10 ) according to claim 1 , wherein the angle of the arch of the leading edge ( 11 ) or the envelope curve ( 21 ) thereof is not equivalent to the angle of the arch of the trailing edge ( 12 ) or the envelope curve ( 22 ) thereof.

9. The blade ( 10 ) according to claim 1 , wherein the two opposite end edges ( 17 , 18 ) are spaced from one another at the leading edge ( 11 ) at a leading edge spacing (a) and the two opposite end edges ( 17 , 18 ) are spaced apart from one another at the trailing edge ( 12 ) at a trailing edge spacing (b), and the leading edge spacing (a) is greater than the trailing edge spacing (b).

10. The blade ( 10 ) according to claim 1 , comprising at least two fastening holes ( 13 ) for securing the blade ( 10 ) to a rotor ( 1 ), wherein at least one of the fastening holes ( 13 ) takes the form of a slot, thereby allowing adjustability in a fastening position on the rotor ( 1 ).

11. A screen for treating a fibrous pulp suspension comprising:
a rotor ( 1 ) defining an axis ( 2 ) and having a plurality of blades ( 10 ) secured thereto, and
a screen basket ( 8 ) circumscribing the rotor ( 1 ), wherein
the blade ( 10 ) extends between a leading edge ( 11 ) and a trailing edge ( 12 ) with two opposite end edges ( 17 , 18 ) therebetween and defines an upper side and lower side, the leading edge ( 11 ) or an envelope curve ( 21 ) thereof being arched in a direction toward the trailing edge ( 12 ), the trailing edge ( 12 ) or the envelope curve ( 22 ) thereof being arched in a common direction ( 23 ) relative to the leading edge ( 11 ), wherein the blade ( 10 ) has a cross-section with a wing-shaped profile having a convex upper surface.

12. The screen according to claim 11 , wherein the blades ( 10 ) are secured to the rotor ( 1 ) such that a straight line ( 16 ) between points ( 14 , 15 ) in the opposite end edges ( 17 , 18 ) at the leading edge ( 11 ) is substantially parallel to the rotor axis ( 2 ).

13. The screen according to claim 11 , wherein the blades ( 10 ) are secured to the rotor ( 1 ) on a slant such that a straight line ( 16 ) between the two endpoints ( 14 , 15 ) of the leading edge ( 11 ) between points ( 14 , 15 ) in the opposite end edges ( 17 , 18 ) at the leading edge ( 11 ) is not parallel to the rotor axis ( 2 ).

14. The screen according to claim 11 , wherein multiple blades ( 10 ) are mounted spaced apart from one another over the rotor height (Z) and a spacing (Y) between the respective blades and the screen basket ( 8 ) varies over the rotor height (Z).

15. The screen according to claim 13 , wherein multiple blades ( 10 ) are mounted over the rotor height (Z) and have different slants from one another.

16. A blade ( 10 ) for screens used to treat a fibrous pulp suspension which blade ( 10 ) can be secured to a screen rotor ( 1 ), comprising:
a section extending from a leading edge ( 11 ) to a trailing edge ( 12 ) with two opposite end edges ( 17 , 18 ) extending therebetween, the section between the leading edge ( 11 ) and trailing edge ( 12 ) defining an upper side and lower side, wherein
the leading edge ( 11 ) or an envelope curve ( 21 ) thereof has a concave shape and the trailing edge ( 12 ) or an envelope curve ( 22 ) thereof has a concave shape, and
the blade ( 10 ) has a wing-shaped cross section with a convex upper surface.

17. The blade ( 10 ) according to claim 16 , wherein the curve of the concave leading edge ( 11 ) or the envelope curve ( 21 ) thereof is symmetrical across a center line ( 24 ).

18. The blade ( 10 ) according to claim 16 , wherein the curve of the concave trailing edge ( 12 ) or the envelope curve ( 22 ) thereof is symmetrical across a center line ( 24 ).

19. The blade ( 10 ) according to claim 16 , comprising two fastening holes ( 13 ) in the section between the leading edge ( 11 ) and trailing edge ( 12 ), wherein one hole lies on a center line ( 24 ) extending from the leading edge ( 11 ) to the trailing edge ( 12 ) and the other hole does not lie on the center line ( 24 ).

20. The blade ( 10 ) according to claim 16 , comprising two fastening holes ( 13 ) in the section between the leading edge ( 11 ) and trailing edge ( 12 ), wherein one hole takes the form of a slot extending in the direction of two opposite end edges ( 17 , 18 ) that connect the leading edge ( 11 ) and the trailing edge ( 12 ).

Assignees

• Andritz Ag Maschf

Inventors

• Gscheider Alexander
• Hertl Erwin

Classifications

• D21D5/026 Primary

  with rotating cleaning foils · CPC title