System for fastening a seal to a rotor blade of a rotary feeder
A fastening system having a supporting strip, to which is fastened, outside the housing of the rotary feeder, a seal designed to seal the blade of the rotor in relation to the housing. The mounted unit of supporting strip and seal is inserted into a groove devised in the blade. This installation unit is then secured to the blade by means of securing screws. The seal can be made from a hard seal, especially steel, or a soft seal, especially rubberized textile, attached on the outside by a locating strip.
1. A system to fasten a seal to a rotor blade of a rotary feeder of loose material, the system comprising:
a sealing edge formed on the seal secured to the rotor blade, the sealing edge arranged above a top edge of the rotor blade;
a groove formed below the top edge and formed in a wall of the rotor blade that is substantially parallel with an axis of a rotor;
a supporting strip that is attached to the seal by fastening screws; and
the supporting strip being removingly secured in the groove, the supporting strip having a first contact surface having a shape that substantially matches with a shape of the groove and a having a second contact surface directly in contact with a contact surface of the seal,
wherein the seal and the supporting strip form a rigid unit with the rotor blade and are fixed to the rotor blade with at least one securing screw,
wherein on each side of the groove, there is formed at least one anchor hole in the rotor blade, which is adapted to the at least one securing screw, and
wherein a length of each of the fastening screws is less than a total thickness of the seal and the supporting strip and a length of the at least one securing screw is greater than the total thickness of the seal and the supporting strip, such that the fastening screws are shorter than the at least one securing screw.
2. The system according to claim 1 , wherein the seal is a hard seal of abrasion-resistant material.
3. The system according to claim 1 , wherein the groove has a concave cross section or a dovetail shape or a two-tiered dovetail shape.
4. The system according to claim 1 , wherein the supporting strip comprises at least one through hole which is concentric with the at least one anchor hole in the rotor blade when the supporting strip is fully inserted into the groove, and wherein the seal comprises at least one through hole which is concentric with the at least one anchor hole in the rotor blade and the at least one through hole in the supporting strip.
5. The system according to claim 1 , wherein the groove comprises, in a radial direction from the axis of the rotor to the top edge of the rotor blade, an oblique bottom surface, pointing radially inward towards the axis of the rotor at a slant from the wall of the rotor blade, wherein a normal bottom surface adjoins the oblique bottom surface at least up to an area beneath the at least one anchor hole, wherein above the at least one anchor hole there is formed an oblique top surface with opposite inclination to that of the oblique bottom surface, and wherein the oblique top surface is adjoined at an acute angle by a normal top surface, which is substantially parallel to the normal bottom surface.
6. The system according to claim 5 , wherein the normal bottom surface is in the same plane as the normal top surface.
7. The system according to claim 1 , wherein the supporting strip comprises threaded holes for the fastening screws and the seal comprises through holes with a conical recess having a similar conicity as conical bevelled heads of the fastening screws.
8. The system according to claim 7 , wherein the seal is formed by a hard seal and provided with a nose whose bearing surface rests against a tangential surface formed on the supporting strip with respect to the axis of the rotor.
9. The system according to claim 8 , wherein a distance of an axis of the conical recess from the bearing surface is less than a distance of the axis of at least one through hole of the supporting strip from a tangential surface by a first eccentricity amounting to 5 to 15% of a diameter of the at least one securing screw.
10. The system according to claim 9 , wherein the distance of the axis of the conical recess from the bearing surface is less than a distance of the axis of the threaded hole of the supporting strip from the tangential surface by a second eccentricity amounting to 5 to 15% of the diameter of the fastening screws.
11. The system according to claim 1 , wherein the seal is a soft seal of nonabrasive material, against which a locating strip is pressed in the direction of the rotor blade.