Material feeding device for VSI-crusher

A method of crushing material, said method comprising the steps of:

• feeding a first flow of material to be crushed to a rotor rotating around a vertical axis,
• accelerating said first flow of material in said rotor towards an impact wall section of a housing surrounding the rotor,
• feeding a second flow of material through at least one outlet of an inner hopper to a space formed between said inner hopper and an outer hopper surrounding said inner hopper,
• allowing said second flow of material to slide on a slide plate located in said space adjacent to said at least one outlet, wherein the slide place is inclined in a direction substantially tangential in relation to the rotor, such that material leaving said at least one outlet will slide on the slide plate and obtain a movement in a direction having a substantially tangential component in relation to the rotor, and wherein an angle between a horizontal plane and the slide plate is adjusted via an adjustment device;
• and
• feeding the second flow of material to be crushed into the path of the accelerated first flow of material,
• wherein a direction arm is fixed between the inner and outer hoppers, the slide plate being mounted on the direction arm, and, when viewed in a direction perpendicular to the horizontal plane, a portion of the slide plate extends past an edge of the direction arm in the direction having the substantially tangential component in relation to the rotor.

A vertical shaft impact crusher for crushing material, said crusher comprising

• a rotor for accelerating a first flow of material to be crushed,
• a first feed means for feeding the first flow of material to the rotor,
• a housing comprising a circumferential impact wall section against which the accelerated first flow of material may be crushed, and
• a second feed means for feeding a second flow of material to be crushed into the path of the accelerated first flow of material, the second feed means comprising an inner hopper and an outer hopper, the inner hopper including at least one outlet for allowing said second flow of material to enter a space formed between said inner and outer hoppers, a slide plate adjacent to said at least one outlet is located in the space between said inner and outer hoppers, the slide plate is inclined in a direction being substantially tangential in relation to the rotor, such that material leaving said at least one outlet will slide on the slide plate and obtain a movement in a direction having a substantially tangential component in relation to the rotor,
• wherein an adjustment device is connected to the slide plate to adjust an angle between the slide plate and a horizontal plane;
• wherein a direction arm is fixed between the inner and outer hoppers, the slide plate being mounted on the direction arm, and, when viewed in a direction perpendicular to the horizontal plane, a portion of the slide plate overlaps an edge of the direction arm in the direction having the substantially tangential component in relation to the rotor;
• wherein the at least one outlet of the inner hopper has a movable hatch configured to be placeable in different positions on the inner hopper to obtain a desired open area of the at least one outlet;
• wherein a blocking device is located underneath the slide plate such that the angle between the slide plate and the horizontal plane is adjusted together with a position placement of the blocking device;
• and
• wherein the slide plate includes a wear resistant coating on the surface on which the second flow of material is operative to slide, and the coating is a ceramic coating.