An actuator is configured to couple with a controlled member and includes first and second pistons disposed in respective internal chambers. The first piston may be moveable between first and second positions. The second piston may be moveable between third and fourth positions. The second piston may be configured not to engage the first piston when the second piston is disposed at the third position. The second piston may be configured to move the first piston to the second position as the second piston moves from the third position to the fourth position. A resilient member may be disposed to resiliently urge the second piston toward the fourth position.

An actuator is configured to couple with a controlled member and includes first and second pistons disposed in respective internal chambers. The first piston may be moveable between first and second positions. The second piston may be moveable between third and fourth positions. The second piston may be configured not to engage the first piston when the second piston is disposed at the third position. The second piston may be configured to move the first piston to the second position as the second piston moves from the third position to the fourth position. A resilient member may be disposed to resiliently urge the second piston toward the fourth position.

A comminutor reduces the size of particles of frangible blast media from each particle's respective initial size to a size smaller than a desired maximum size. The frangible blast media may be entrained in a flow of transport gas. The comminutor includes an inlet and an outlet, both in fluid communication with an internal flow passageway. The internal flow passageway includes a first intermediate passageway which comprise the gap defined by two rotating rollers and a second intermediate passageway which includes an inlet disposed proximal the gap, extending in an upstream direction therefrom.

A comminutor reduces the size of particles of frangible blast media from each particle's respective initial size to a size smaller than a desired maximum size. The frangible blast media may be entrained in a flow of transport gas. The comminutor includes an inlet and an outlet, both in fluid communication with an internal flow passageway. The internal flow passageway includes a first intermediate passageway which comprise the gap defined by two rotating rollers and a second intermediate passageway which includes an inlet disposed proximal the gap, extending in an upstream direction therefrom.

Disclosed is a deflection distributor refitting kit for a roller crusher. According to the disclosure the deflection distributor refitting kit comprises a deflection distributing shaft, thrust rods each having first and second ends and mounts for attachment of the deflection distributing shaft at a frame of the roller crusher, wherein a first end of each of said thrust rods is attached to the deflection distributing shaft via a lever, and wherein a second end of each of the thrust rods is arranged to be attached to a movable bearing housing of the roller crusher. Also disclosed is a method for mounting the deflection distributor refitting kit, as well as a roller crusher comprising a deflection distributor.

Disclosed is a deflection distributor refitting kit for a roller crusher. According to the disclosure the deflection distributor refitting kit comprises a deflection distributing shaft, thrust rods each having first and second ends and mounts for attachment of the deflection distributing shaft at a frame of the roller crusher, wherein a first end of each of said thrust rods is attached to the deflection distributing shaft via a lever, and wherein a second end of each of the thrust rods is arranged to be attached to a movable bearing housing of the roller crusher. Also disclosed is a method for mounting the deflection distributor refitting kit, as well as a roller crusher comprising a deflection distributor.

A roller mill for comminuting bulk material may include a first grinding roller and a second grinding roller that are arranged opposite one another and can be driven in opposite directions. A grinding gap exists between the grinding rollers. A floating bearing unit may be configured to receive the first grinding roller, and a fixed bearing unit may be configured to receive the second grinding roller. The floating bearing unit includes two bearings, each of which receives one end of the first grinding roller. Hydraulic actuators are mounted on the floating bearing unit for applying a force to the floating bearing unit. The bearings of the floating bearing unit are connected to one another via a synchronization device that includes a coupling element, which in a coupling position prevents a relative movement of the bearings and in a free position permits a relative movement of the bearings.

A roller mill for comminuting bulk material may include a first grinding roller and a second grinding roller that are arranged opposite one another and can be driven in opposite directions. A grinding gap exists between the grinding rollers. A floating bearing unit may be configured to receive the first grinding roller, and a fixed bearing unit may be configured to receive the second grinding roller. The floating bearing unit includes two bearings, each of which receives one end of the first grinding roller. Hydraulic actuators are mounted on the floating bearing unit for applying a force to the floating bearing unit. The bearings of the floating bearing unit are connected to one another via a synchronization device that includes a coupling element, which in a coupling position prevents a relative movement of the bearings and in a free position permits a relative movement of the bearings.

A roller mill for comminution of bulk material may include a first grinding roller and a second grinding roller that are arranged opposite one another and are configured to be driven in opposite directions. The grinding rollers may be positioned with a grinding gap therebetween. A fixed bearing unit may be configured to hold the second grinding roller, and a floating bearing unit may be configured to hold the first grinding roller. Attached to the floating bearing unit are hydraulic actuators for applying a force to the floating bearing unit. The hydraulic actuators are hydraulically connected to a synchronization device. The synchronization device has a plurality of hydraulic cylinders, each having a piston. The pistons may be connected to one another via a mechanical coupling such that movements of the pistons are coupled.

A roller mill for comminution of bulk material may include a first grinding roller and a second grinding roller that are arranged opposite one another and are configured to be driven in opposite directions. The grinding rollers may be positioned with a grinding gap therebetween. A fixed bearing unit may be configured to hold the second grinding roller, and a floating bearing unit may be configured to hold the first grinding roller. Attached to the floating bearing unit are hydraulic actuators for applying a force to the floating bearing unit. The hydraulic actuators are hydraulically connected to a synchronization device. The synchronization device has a plurality of hydraulic cylinders, each having a piston. The pistons may be connected to one another via a mechanical coupling such that movements of the pistons are coupled.