Roller crusher and method for operation thereof

A method for operating a roller crusher for grinding granular material, wherein the roller crusher has two generally parallel rollers arranged to rotate in opposite directions, and separated by a gap, each roller having two ends, the roller crusher comprising:

• a flange attached to one of the ends of one of the rollers, the flange extending in a radial direction of the roller, and the flange having an extension (E) past an envelope surface of the roller,
• wherein the roller crusher further comprises a scraper device comprising:
• a rotatable multi head scraper unit having at least two scrapers arranged tangentially about the rotatable multi head scraper unit at a respective radial distance from a rotational axis of the rotatable multi head scraper unit;
• a rotation actuator arranged to selectively rotate the rotatable multi head scraper unit to allow operative use of one of the at least two scrapers at a time;
• and
• at least one brake arrangement configured to prevent and/or restrict rotation of the rotatable multi head scraper unit during operation of the one of the at least two scrapers,
• wherein each of the at least two scrapers comprises a scraping element having a scraping surface which scraping surface comprises a polycrystalline diamond (PCD) and wherein the rotatable multi head scraper unit is structured and arranged such that each scraping surface at least partly faces in a tangential direction defined at the scraper surface and directed along a reference rotational direction of the rotatable multi head scraper unit,
• wherein the rotatable multi head scraper unit is arranged such that one of the at least two scrapers, by the rotation actuator, is selectively positionable at an end of a roller having a flange, and, by the at least one brake arrangement, is prevented and/or restricted to move relative to the roller;
• wherein the method comprises at least the step of:
• at least partially removing material accumulated on the flange and/or on the envelope surface at an end portion of the roller adjacent the flange by means of the one of the at least two scrapers.