Roller mill

A method for maintaining the thickness of a grinding cushion of a roller mill at a substantially constant preset thickness, the roller mill having means for producing a mean grinding pressure and means for monitoring a mean thickness of the grinding cushion, comprising monitoring the mean thickness of the grinding cushion and regulating the grinding pressure within a predetermined range in accordance with variations in the mean thickness of the grinding cushion about said preset thickness, continuously increasing the mean grinding pressure within said predetermined range as long as the mean thickness of the grinding cushion exceeds said preset thickness and until the thickness of the grinding cushion has returned to said preset thickness, and continuously decreasing the mean grinding pressure within said range as long as the mean thickness of the grinding cushion is less than said preset thickness and until the thickness of the grinding cushion has returned to said preset thickness.

A method for maintaining the thickness of a grinding cushion of a roller mill having a rotating grinding table having a grinding path thereon, a plurality of grinding bodies positioned to be pressed toward said grinding path to provide a grinding pressure for grinding material forming a grinding cushion therebetween, structural means for supporting grinding bodies for grinding rotation along said grinding path, means for monitoring a mean thickness of the grinding cushion and hydraulically controlled means for hydraulically providing increases and decreases in the grinding pressure comprising generating a signal which increases the grinding pressure within fixed limits when the mean thickness of the grinding cushion exceeds a predetermined value and decreases the grinding pressure within said limits when the mean thickness of the grinding cushion is less than said predetermined value, said grinding pressure being increased and decreased respectively by said hydraulic means, continuously increasing or decreasing the mean grinding pressure within a predetermined range as long as the mean thickness of the grinding cushion exceeds or is less than said predetermined value, respectively, and until the thickness of the grinding cushion has returned to said predetermined value.

A roller mill having a rotating grinding table having a grinding path thereon, a plurality of grinding bodies positioned to be pressed toward said grinding path to provide a grinding pressure for grinding material forming a grinding cushion therebetween, structural means for supporting grinding bodies for grinding rotation along said grinding path, means for monitoring a mean thickness of the grinding cushion, controlled hydraulic means for providing forces which increase and decrease the grinding pressure, means for generating a signal which continuously increases the grinding pressure within fixed limits as long as the mean thickness of the grinding cushion exceeds a predetermined value and until the thickness of the grinding cushion has returned to said predetermined value and continuously decreases the grinding pressure within said limits as long as the mean thickness of the grinding cushion is less than said predetermined value and until the thickness of the grinding cushion has returned to said predetermined value, said grinding pressure being increased and decreased respectively by said hydraulic means.

A mill for maintaining the thickness of its grinding cushion at a substantially constant predetermined value, comprising means for producing grinding pressures by hydraulic forces, means for measuring the thickness of the grinding cushion and means for continuously increasing or decreasing the hydraulic forces as long as the thickness of the grinding cushion is either larger or smaller, respectively, than said predetermined value and until the thickness of the grinding cushion has returned to said predetermined value.