Patent ID: 7028934

Claim:
A vertical roller mill in which the grinding force is supplied by a hydraulic cylinder having a piston side and a rod side, wherein said roller mill contains an accumulator assembly hydraulically connected to either the piston or rod side of the hydraulic cylinder, said accumulator assembly comprising at least two accumulators being hydraulically interconnected to the same source of hydraulic fluid, each of the two accumulators containing an energy absorbing medium which is compressible when a movable barrier which separates the hydraulic fluid from the energy absorbing medium is acted upon by an increase in pressure of the hydraulic fluid, wherein at least one of said at least two accumulators contains a compressibility limiter which interrupts the compressibility of the energy absorbing medium within the accumulator and at least one of said at least two accumulators does not contain a compressibility limiter so that its energy absorbing media may be fully compressed by the hydraulic fluid.