Abstract: An accumulator is connected to a source of hydraulic fluid, comprising a movable barrier which separates the hydraulic fluid from a compartment containing two distinct energy absorbing medium—a first energy absorbing medium and a second energy absorbing medium. The movable barrier, when acted upon by an increase in pressure of the hydraulic fluid, will move in a first direction to initially contact and begin compressing the first energy absorbing medium. When the movable barrier moves further in said first direction it will contact the second energy absorbing medium and will begin compressing the second energy absorbing medium while still compressing the first energy absorbing medium.

Abstract: An accumulator assembly comprising at least two accumulators that are hydraulically interconnected to the same source of hydraulic fluid. Each accumulator 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. When the assembly contains two accumulators, one accumulator contains a compressibility limiter which interrupts the compressibility of the energy absorbing medium within the accumulator and the other accumulators does not contain a compressibility limiter so that the energy absorbing media therein may be fully compressed by the hydraulic fluid. The accumulator assembly is favorably utilized in a vertical roller mill.