Abstract: A grinder includes a grinding table rotatable about a first rotational axis and at least two grinding rollers. Each of the at least two grinding rollers is arranged for rotation about a second rotational axis such that ground material can be comminuted between the grinding table and the grinding rollers during operation. A sensor arrangement can detect a change in inclination of the grinding table beyond a given threshold value.

Abstract: A method for determining and providing signal displays is provided. The method can include receiving data characterizing signal values. The data can be received from a sensor monitoring an asset, such as a rotating machinery asset. The method can also include receiving data characterizing a threshold trigger level associated with the asset. The method can further include determining a signal display for the asset. The method can also include providing the signal display in a graphical user interface. Monitoring systems for monitoring industrial assets and providing signal displays corresponding to an operation of the industrial assets are also provided.

Abstract: A drive device for a working machine for heavy industry, particularly for the raw-materials and mining industry, includes a permanent-magnet-excited motor and a frequency converter, wherein the motor has a rotor and a stator, and wherein the motor is a segment motor, in the case of which the rotor and/or the stator is composed of a plurality of segments, where considerable improvement in the availability of the motor is achieved because the motor has a segmented design, whereby the reliability during operation of the drive device is also increased.

Abstract: A 3D-slanted roll crusher includes a housing, a number of driving devices mounted to the housing, a base mounted to an end of the housing away from the driving devices, a number of groups of grinders, a number of grinding teeth mounted on each of the grinders, and a number of material obstructing bodies mounted on an inner wall of the housing. The grinders correspond to the driving members one-to-one. Each grinder is connected to the base and the corresponding driving device. The grinders are spaced equally apart within the housing around a central axis of the housing and slantedly mounted on the base facing the driving devices.

Abstract: The present disclosure relates to a pulverizer includes a pulverizer housing with an grinding assembly having a grinding table situated therein. The grinding table provides a grinding surface area for a material, such as a fossil fuel, such as coal, to be pulverized. The grinding table is mounted on a gearbox shaft operatively connected to a gearbox drive mechanism so as to be capable of driven rotation within the pulverizer housing. A journal assembly having a journal head and the journal assembly and a spring assembly are mounted on the pulverizer housing so that the journal head engage the spring assembly.

Abstract: A mill for crushing a bed of materials by compression includes: a horizontal-axis cylinder the interior wall having a runway track for a crushing roller placed inside the cylinder, a unit rotating the cylinder at a speed that spins the material outward, the crushing roller, a unit for pressing the crushing roller against the runway track of the cylinder, an inlet for supplying material for crushing at one end of the cylinder and an outlet for crushed material at the other end, a unit for controlling the movement of the material so it travels over only a fraction of the length of the cylinder in each revolution and passes between the cylinder and the roller several times before reaching the outlet. The runway track is followed by a downstream lip opposing material flow, downstream of the crushing roller in the direction in which the material travels.

Abstract: A method for grinding a grinding material in a mill including a grinding body and at least one roller which rolls on the grinding body under a grinding pressure, wherein the grinding material is fed in a stream of grinding material, forms a grinding bed between the grinding body and the roller and is crushed in the grinding bed by the roller, wherein a grinding bed height of the grinding bed between the grinding body and the roller is continuously measured, and wherein the mill is controlled based on control variables to achieve a predetermined nominal condition, wherein the control variables include at least the grinding pressure and the stream of the grinding material and the nominal condition includes at least one nominal value for the grinding bed height, wherein a mechanical condition of the roller and therefrom a stability of the grinding bed are continuously determined.

Abstract: A method and a device for controlling the drive of a vertical mill having a grinding plate rotatable about the vertical axis are disclosed. The grinding plate can be driven by an electric motor and a drivetrain with a gearbox. An actual rotational speed and a drivetrain torque with respect to the drivetrain are detected and are fed to a control device together with a specified target rotational speed. The control device generates an output signal for a target torque based on the actual rotational speed and the target rotational speed and based on the drivetrain torque such that the resulting target torque is reduced or increased in the same direction as a torque resulting from the milling process.

Abstract: The roller mill for grinding of material to be ground prescribed by the invention has a grinding table and at least one grinding roller which works with the grinding table, whereby a water lance for applying water to the material to be ground is placed in the rotation direction of the grinding table in front of the grinding roller. The water lance is designed to rotate and means for rotating the water lance are provided in order to specifically influence the exposure time of the water to the material to be ground before the material to be ground is gathered by the grinding roller.

Abstract: The invention relates to a roller mill, in particular a coal mill, with a feed system, having an integrated screw feeder. The screw feeder is arranged virtually horizontally in the region of a grit cone and comprises a screw shaft guided through the roller mill and the longitudinal axis thereof, which screw shaft is arranged on both sides respectively outside of the roller mill and at one end with a drive means and at the other end in a bearing outside of the roller mill. The feed material is fed with the screw conveyer outside of the roller mill and forcibly conveyed therein to a tray side rejection opening above a cone opening of the grit cone and drops together with the coarse grain rejected in the classifier centrally onto the grinding pan. An even distribution of the feed material and improved smooth running of the roller mill and energy saving are achieved and also soiling of the screw shaft is avoided.

Abstract: In a vertical mill, a mill table is supported in a housing by a support shaft center, which is along a vertical direction, in such a manner as to be driven and rotated, and above the mill table, a mill roller is rotatably supported by a first support shaft, and the mill roller is capable of rotating the mill table in such a manner that an external peripheral surface of the mill roller comes into contact with an upper surface of the mill table, and a support arm configured to support the first support shaft is swingably supported on the housing by a second support shaft, in such a manner that the mill roller can come close to or move away from the mill table, and a reaction force load giving device is provided that has a dumper filled with a magnetorheological fluid and magnetizes the magnetorheological fluid.

Abstract: The invention relates to a roller mill having a grinding table, at least one grinding roller and at least two drives with a rotor winding for driving the roller mill and at least one adjustment device for adjusting the motor torque of at least one drive, the adjustment device being connected to the rotor winding of at least one drive in order to influence the rotor current.

Abstract: A heavy-duty drive arrangement for a mill having a grinding bowl ratable about a vertical axis comprises a housing, an electric motor, and a gearing arrangement disposed in the housing and supported on the housing. The grinding bowl can be driven by means of the electric motor via the gearing arrangement. The electric motor is disposed below the gearing arrangement. The electric motor is integrated in the housing. Advantageously, the electric motor is supported on the housing particularly on a bottom element of the housing. The rotor can be connected directly, or via a coupling integrated in the rotor, to a gear of the gearing arrangement. The mill may be, for example, a roller bowl mill.

Abstract: The roller mill according to the invention substantially comprises at least one grinding roller and a grinding table, the grinding table having a grinding table inner space which is open in a downward direction, at least one grinding roller drive system for driving the grinding roller and a grinding table drive system for driving the grinding table. The grinding table drive system further has a gearless direct drive which is arranged in the grinding table inner space.

Abstract: In a drive arrangement for a heavy duty mill an electric motor with a high number of magnetic poles and a stator that is segmented into at least four stator segments is used. By providing one, more or all of the stator segments with a three phase winding system, a highly modular mill drive with a high power density and therefore reduced space requirements is provided.

Abstract: In a vertical mill, a pulverization table is supported with a vertical rotation axis core in a housing so as to be capable of being driven and rotated, and a pulverization roller rotatable in conjunction with rotation of the pulverization table is disposed above the pulverization table so as to be opposed to the pulverization table, and a roller swing mechanism is provided so as to make the pulverization roller parallel to a surface of the pulverization table and swingable in a direction different from a direction of rotation of the pulverization table. Accordingly, a solid matter such as biomass can be efficiently pulverized, thereby achieving improvement in pulverization efficiency.

Abstract: Load cells are placed in the pre-compression systems of spring suspended rollers in coal/ore crusher/classifiers to produce electrical signals representing actual forces generated in the suspension system during crusher operation. This permits forces to be closely monitored during operation and/or automatically adjusted. Alternatively or in addition, alarm signals can be generated when pressures go out of tolerance.

Abstract: In grinding of a raw material by a vertical roller mill, highly-efficient grinding is performed irrespective of the type of the raw material, and the life of the mill roller is extended. In order to achieve these, in a grinding roller used in a vertical roller mill, an outer circumferential surface of the roller as a grinding surface is divided into a main grinding surface that mainly performs pulverizing and a grinding surface other than the main grinding surface. The main grinding surface is made smooth, and the grinding surface other than the main grinding surface is a raw material transfer surface in which slit grooves inclined at 90 degrees or an angle exceeding 45 degrees relative to a roller circumferential direction or screw grooves inclined at 45 degrees or smaller relative to the roller circumferential direction are formed.

Abstract: In a vertical mill, a pulverization table (13) is supported with a vertical rotation axis core in a housing (11) so as to be capable of being driven and rotated, and a pulverization roller (18) rotatable in conjunction with rotation of the pulverization table (13) is disposed above the pulverization table (13) so as to be opposed to the pulverization table (13), and a cutter roller (19) rotatable in conjunction with rotation of the pulverization table (13) is disposed above the pulverization table (13) so as to be opposed to the pulverization table (13). Accordingly, a solid matter such as biomass can be efficiently pulverized, thereby achieving improvement in pulverization efficiency.

Abstract: The invention relates to the grinding method with simultaneous homogenization of powder-like materials with liquid components in construction engineering, chemical and other industries. The roller breaker-homogenizer comprises a cone-shaped backing roll and not less than three driven rolls and driven rolls, the large bases of which face reverse directions. The rolls are arranged in the case with a replaceable cup vertically at the same level so that the driven rolls are located epicyclically relative to the backing roll and mounted in cantilever fashion in the case cover rotation bearing assemblies, and the backing roll is connected axially with a drive shaft via a spring coupling. An appliance used to regulate the spring coupling pressing force is mounted between the drive and spring coupling. The case cover has an opening for loading basic process materials above the upper end surface of the backing roll, and an anchor-type mixer is fixed on the lower end surface of the backing roll.

Abstract: A deflector (30) for a pulverizing bowl mill (10) includes a plurality of first upper plates (72) and a plurality of second upper plates (74) arranged with the first upper plates (72) to form the deflector (30) positionable on an inner surface of a substantially closed separator body (12) of the pulverizing bowl mill (10). Each of the second upper plates (74) comprises a skirted lower edge (75) that extends beyond a lower edge of each of the first upper plates (72). Each of the second upper plates (74) is also positionable in the pulverizing bowl mill (10) upstream of a journal (24) supporting a grinding roller (22) to deflect a flow of air (32) around the journal (24).

Abstract: A roller mill (1) for grinding particulate material such as cement raw materials, cement clinker, coal and similar materials, said roller mill (1) comprising a substantially horizontal grinding table (3) and a set of rollers revolving about a vertical shaft (5); said set of rollers comprising a number of rollers (4) rotatable about respective roller axes and being connected via a roller bearing (16) and a roller shaft (6) to the vertical shaft (5), and said set of rollers (4) being configured for interactive operation with the grinding table (3) for application of pressure to the particulate material; characterized in that each roller bearing (16) across its entire axial extent is axially located radially towards the vertical shaft (5) inwardly of the location of the resulting force from the grinding zone imposed upon the respective roller, in use.

Abstract: The invention relates to a method for comminuting material to be ground having a roller mill which has a mill platen, at least one mill roller and at least two drives for driving the roller mill, with there being provided a power compensation control system for the drives which controls the power of the drives at a predetermined ratio relative to each other by the speed of at least one drive being controlled.

Abstract: Described is a rolling bearing (1) for a rocker arm, said rolling bearing comprising an at least partly circular outer part (2), an at least partly circular inner part (3) and a number of rolling elements (5) which are fitted between the outer part (2) and the inner part (3). The rolling bearing is peculiar in that at least one of the rolling elements (5) comprises two opposite, curved side faces (6, 7), which viewed in at least one cross-sectional constitutes arc lengths of the same imaginary circle (10), and which constitutes contact faces for the outer and the inner circular part (2, 3) respectively, and at least one side surface (8, 9), which lies within the mentioned imaginary circle (10). It is hereby obtained that the number of rolling elements in the bearing can be increased, thereby reducing the load on each single rolling element subject to the same total load rate, thereby increasing the total load bearing capacity of the bearing.

Abstract: A roller mill (1) for grinding particulate material such as cement raw materials, cement clinker and similar materials has a substantially horizontal grinding table (3) and a set of rollers revolving about a vertical shaft (5). The set of rollers includes a number of rollers (4) rotating about respective roller shafts (6) which are connected to the vertical shaft (5) via a hinged connection (7) which has a bearing shell (14) and a bearing journal (15) resting therein. The hinged connection (7) allows a free arcuate movement of the roller (4) in an upward and downward direction in a plane including the centerline (12) of the roller shaft. The set of rollers (4) is configured for interactive operation with the grinding table (3), and the bearing shell (14) of the hinged connection (7) has a diameter which exceeds that of the bearing journal (15) resting therein by a factor of at least 1 percent.

Abstract: A pulveriser mill has a grinding set (2) supported by a support table (4), the support table having on its underside supporting parts 8?, 10?, 12?. By such means the working life of the support table may be extended.

Abstract: The invention relates to a roller mill having at least one mill roller and a rotatable mill platen, which are arranged in a mill inner space, and a moment arm which is retained so as to be pivotably movable and rotationally secure in a bearing, with the mill roller being supported in a rotatable manner at one end of the moment arm and there further being provided means for applying a force to the moment arm comprising a pressure cylinder which is in operative contact with the moment arm in order to adjust the mill pressure which is applied by the mill roller. The contact location, at which the force of the pressure cylinder is transmitted to the moment arm, is located outside the mill inner space.

Abstract: A roller mill for grinding particulate material such as cement raw materials, cement clinker and similar materials comprises a mill housing surrounding a substantially horizontal grinding table, a number of rollers each rotating about a roller shaft and configured for interactive operation with the grinding table and at least one mechanism or device for introducing gases into the mill housing. The at least one mechanism or device for introducing gases into the mill housing comprises an annular duct having openings in a wall facing the grinding table and being located around the outer circumference of the grinding table. As a consequence hereof, a significant reduction of the pressure loss in a roller mill and thus a significant reduction of energy consumption will be ensured.

Abstract: A grinding system includes a mill housing. A milling unit in the housing has a moveable milling member operable to grind coal. A drive system includes a drive shaft and at least one gear in a gear case drivingly connecting the milling member to the drive shaft. An exhauster is operable to draw air into the housing through an inlet and draw a mixture of air and powdered coal out of the housing through an outlet. A pressurization system is operable to maintain the gear case pressure at a higher pressure than an air pressure in the housing. In one method of grinding coal a gear case pressure is maintained at a pressure higher than a pressure at the housing inlet while the milling member grinds coal into a powder and the exhauster draws a mixture of powdered coal and air out of the housing.

Abstract: A drive systems for a roller mill is provided. To ensure the continuous availability of the mill, more than two drives are provided, wherein the at least two drives are capable of achieving the full grinding capacity of the roller mill.

Abstract: A plunger can for a roller assembly within a pulverizing mill has a body which contains a compression spring. A stub shaft transfers the force generated by the compression spring to the roller assembly. A bushing in cooperation with a locking guide in the fore end of the plunger can, along with the stub shaft in an aft end of the plunger can, contains the compression spring there between. The locking guide has an annular flange that fits within an annular channel within the plunger can body. A plurality of extensions spaced around an outside perimeter of the annular flange cooperates with a plurality of extensions around an inside perimeter of the plunger can body such that both sets of extensions clear each other when the locking guide is inserted into the plunger can body. When rotated, the sets of extensions are aligned with each, forming a mechanical lock.

Abstract: The invention relates to a vertical mill comprising a grinding track (1) and at least one grinding roller (2). The grinding track (1) is provided with a central zone (Ia) made of a harder material and two laterally adjacent edge zones (Ib, Ic) made of a softer material. The width (a) of the central zone (Ia) is smaller than or equal to the width of the grinding roller (2).

Abstract: A pulverizer upper gearbox bearing assembly for a mill includes a bowl hub having a stepped hub defining a first bore to receive a shaft therethrough and a bowl extending radially outwardly therefrom defining a cavity between the stepped hub and bowl, the stepped hub having a first outside diameter extending to a second outside diameter, which in turn extends to a third outside diameter along a longitudinal axis of the first bore, the first outside diameter larger than the second outside diameter, which is larger than the third outside diameter; a thrust bearing disposed around the first outside diameter, the thrust bearing having an upper washer and a lower washer, the upper washer having an interference fit with the first outside diameter of the bowl hub; a roller bearing disposed around the third outside diameter, the roller bearing having a separable inner ring from an outer ring and a surrounding cage and roller assembly; a mill base hub extending into the cavity between the bowl and stepped hub, the mil

Abstract: A roller mill structure which achieves uniform distribution of fine particles passed through a rotary classifier to fine particle exits disposed at four points when conveying as pulverized coal milled in the roller mill on the air current is provided. A roller mill structure is configured to discharge pulverized coal obtained by milling a raw coal, which is loaded in a mill body (11), from fine particle exits (14) formed on the top of the mill body so as to be quartered in the circumferential direction to the outside by air current conveyance.

Abstract: A grinding mill requiring one or more new grinding balls is adapted so that they can be passed into the mill through spider-guide apertures. The spider-guide apertures provide anchors for spider-guide mountings, by means of which a spider used to grip an upper ring is restrained against rotation. There may be provided two mounting frames between the spider-guide mounting, and the mill. Frame is secured to the mill and has a large opening, able to pass a grinding ball. Frame is secured to frame and has a smaller opening, and provides a mounting location for the spider-guide mounting. The arrangement means that mill disassembly and lifting then lowering grinding balls is no longer needed.

Abstract: In order to minimize the loss of production of a crushing plant, particularly a cement crushing plant and optimize on the gear side the availability of the roller mill, according to the invention a replacement gear is provided alongside the operating mill gear. The mill gear and replacement gear are located on at least one base plate and preferably together with a drive motor for the mill gear and a second motor for the replacement gear, as well as with a lubricating system located between the mill gear and the replacement gear, are preassembled on the base plate. The base plate is horizontally adjustably guided on the mill foundation. If the mill gear fails the base plate with the units mounted thereon can be adjusted in such a way that the replacement gear is positioned below the crushing pan in the place of the mill gear.

Abstract: The invention relates to a method for comminuting material to be ground having a roller mill which has a mill platen, at least one mill roller and at least two drives for driving the roller mill, with there being provided a power compensation control system for the drives which controls the power of the drives at a predetermined ratio relative to each other by the speed of at least one drive being controlled.

Abstract: A bowl mill for a coal pulverizer with an air mill for primary entry of air, comprising a substantially closed separator body (2) having a central axis; and a bowl-like grinding table (3) mounted on a shaft (4) rotatable about said central axis, cooperating with a plurality of grinding rolls (6). The airmill is provided with multiple entry openings (17?, 17?; 18?, 18?; 21, 25) on the outer wall of the air mill for multiple entry of hot primary air from the inlets, resulting in better uniformity in air flow around the air mil section and for minimizing formation of eddies and vortices. As a variation of the multiple entry double entry openings can be arranged for entry of hot primary air.

Abstract: A roller jaw crusher system including an elongated roller that rotates normally about a center axis, and a movable breaking plate configured to define a gradually smaller gap between the breaking plate and the roller, wherein the movable breaking plate is configured to rise upward and descend in both a downward direction and a direction toward the elongated roller to break a frangible material captured between the elongated roller and the movable breaking plate.

Abstract: A roller mill for comminuting solid material having a mixture of hard and soft components which is capable of acting on the solid material at two or more distinct pressures to thereby comminute both hard and soft components of the solid material.

Abstract: A tension adjustment gauge system and method for a ball and ring coal pulverizer is provided that includes a housing, a stationary top grinding ring within the housing, a rotating lower grinding ring within the housing, a plurality of grinding balls between the top grinding ring and the lower grinding ring, an adjustable loading system for applying a compressive force exerted on the top grinding ring and grinding balls against the lower grinding ring. The adjustable loading system includes a single hydraulic assembly mounted on the upper portion of the housing, a gauge mounted to the hydraulic assembly for determining linear movement of a piston of the hydraulic assembly, a plurality of threaded rods mounted to the upper portion of the housing capable of being manually adjusted. The movement of the piston corresponds to an equal distance of movement of a spring gap between an upper and lower portion of the compression spring, such that the gauge indicates the change in the spring gap by moving the piston.

Abstract: The invention relates to a composite milling roller, produced by casting, comprising peripheral inserts of a high wear-resistance and high hardness material, sealed in a ductile material on said casting. The roller comprises first zones subject to high wear and second zones subject to low wear, characterised in that said first zone of said roller comprises inserts on the peripheral face thereof with adjoining parts and, in said second zone, a non-adjoining part. The gap between the non-adjoining parts is filled with said ductile material of the cast matrix permitting an adequate mechanical anchoring of the inserts.

Abstract: A plunger can for a roller assembly within a pulverizing mill has a body which contains a compression spring. A stub shaft transfers the force generated by the compression spring to the roller assembly. A bushing in cooperation with a locking guide in the fore end of the plunger can, along with the stub shaft in an aft end of the plunger can, contains the compression spring there between. The locking guide has an annular flange that fits within an annular channel within the plunger can body. A plurality of extensions spaced around an outside perimeter of the annular flange cooperates with a plurality of extensions around an inside perimeter of the plunger can body such that both sets of extensions clear each other when the locking guide is inserted into the plunger can body. When rotated, the sets of extensions are aligned with each, forming a mechanical lock.

Abstract: A method and apparatus for comminuting particulate material by inter-particle comminution in a bed of particles are disclosed. The apparatus includes a vertical roller mill with a horizontal grinding table rotating about a verticle mill axis. At least one grinding roller presses resiliently against a bed of particulate material on the grinding track and applies a compressive force. The geometry of the mill is such that the roller engages the bed of particulate material with a substantially pure rolling action. This minimises shear forces applied to the particle bed and minimises the reduction of fines.

Abstract: A pulverizer mounted on a foundation and comprising a housing enclosing a pulverizing zone and a base plate attached to the housing. The pulverizing zone includes a horizontally disposed rotatable grinding ring, rolling grinding balls positioned on the grinding ring, and means for rotating the grinding ring including an upright main shaft. An annular yoke is attached to the main shaft, and has an outer peripheral portion which is disposed superjacent to the base plate and supports the grinding ring. A load carrying member or thrust bearing is sandwiched between the base plate and the outer peripheral portion of the yoke to minimize the impact, shock, and eccentric loads that are transmitted from the coal grinding process to the main shaft. The load carrying member or thrust bearing achieves this by transmitting the vertical loads directly through the base plate to the housing and therethrough to the pulverizer foundation.

Abstract: A high efficiency bowl mill (100) is provided by the present invention. Included in the high efficiency bowl mill (100) is a plow (185) that is downstream of a grinding roll (180) on a grinding surface (145). The plow (185) loosens material that has been compacted by the grinding roll (180). Also included is a deflector (165) that redirects an air stream so as to pick up material loosened by the plow (185) and deposit material requiring further grinding. An outlet (201) of an inverted cone (200) is positioned so as to deposit material for pulverization on the grinding surface (145) and to restrict the air stream from entering the inverted cone (200).

Abstract: A bowl mill for a coal pulverizer with an air mill for primary entry of air, comprising a substantially closed separator body (2) having a central axis; and a bowl-like grinding table (3) mounted on a shaft (4) rotatable about said central axis, cooperating with a plurality of grinding rolls (6). The airmill is provided with multiple entry openings (17?, 17?; 18?, 18?; 21, 25) on the outer wall of the air mill for multiple entry of hot primary air from the inlets, resulting in better uniformity in air flow around the air mill section and for minimizing formation of eddies and vortices As a variation of the multiple entry double entry openings can be arranged for entry of hot primary air.

Abstract: A system for use with a roll bowl type mill for the pulverizing of solid fuels such as coal. The system includes hardware in the form of sensors and other components and software to among other things monitor the operating condition of the mill's moving parts and predict their failure. The system can determine the diameter of the mill's rollers, or the reduction and/or depth of cup wear of each of the rollers, the thickness of the solid fuel in the mill, can by analysis determine the wear of each of the one or more roller bearings in the mill and predict their failure and can estimate the mill availability.

Abstract: A pulverizer monitoring system is applicable to at least one pulverizer having a rotatable bowl assembly, and at least one journal assembly having a grinding roll positioned proximal the rotatable bowl assembly, wherein the grinding roll is deflected by the feedstock raw material forced under the roll during rotation of the rotatable bowl assembly. A position sensor is mounted to the journal assembly to detect an amount of deflection of the grinding roll and generates a position signal, wherein a data module is associated with each pulverizer so as to receive the position signal. A calculation engine is linked to each data module for the purpose of analyzing the position signal and other operational signals associated with the pulverizer and generating at least one characteristic pulverizer condition report. A web-based server is linked to the calculation engine to provide network access to the characteristic report(s), either real-time or historical trends.

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.