A system for mechanical separation of materials comprising at least two platforms, each comprising screws undergoing a rotational movement, wherein the screws have a proximal end and a distal end, the distal end being free, wherein the screws of a first one of the at least two platforms all have a first inclination from the proximal end thereof to the distal end thereof; wherein the screws of a second one of the at least two platforms all have a second inclination from the proximal end thereof to the distal end thereof; the first inclination being different from the second inclination. The at least two platforms form a drop in-between along the main direction of travel. There is a double-start thread screw by the drop on the downstream platform that prevents long objects to pass through the screws and optionally a curtain of elongated members by the drop.

A device including a vibrating screen and a motor for causing the vibrating screen to vibrate, wherein the vibrating screen is attached to a rigid frame, wherein the motor is rigidly attached to the frame and causes it to vibrate, wherein the angle between the plane of the vibrating screen and the mounting surface of the motor is in the range of 30 to 60 degrees and/or the legs of the device are attached to the frame.

A static classifier including a vessel having an inlet and an outlet and having a vessel interior area. A classifier chamber is positioned in the vessel interior area. The classifier chamber has a plurality of openings extending through a side wall of the classifier chamber and into a classifier interior area of the classifier chamber. The plurality of openings are configured for passing particles entrained in a gas from the vessel interior area into the classifier interior area. One or more flow restrictors are arranged with the classifier chamber. The flow restrictors are configured to establish an optimal flow velocity and direction of the particles entrained in the gas, through the static classifier.

A static classifier including a vessel having an inlet and an outlet and having a vessel interior area. A classifier chamber is positioned in the vessel interior area. The classifier chamber has a plurality of openings extending through a side wall of the classifier chamber and into a classifier interior area of the classifier chamber. The plurality of openings are configured for passing particles entrained in a gas from the vessel interior area into the classifier interior area. One or more flow restrictors are arranged with the classifier chamber. The flow restrictors are configured to establish an optimal flow velocity and direction of the particles entrained in the gas, through the static classifier.

Disclosed are a hopper, method and system comprising the hopper for separating slack from a mixture of product and slack, the hopper comprising a first gate that is moveable between respective open and closed positions; and a slack removal body the first gate and the slack removal body being arranged such that, when the first gate is in its closed position, they define a first product receiving volume therebetween wherein the slack removal body comprises a first internal chamber for receiving slack and a first filter wall that separates the first internal chamber from the first product receiving volume, the first filter wall being configured to prevent the passage of product therethrough, but to allow the passage of slack therethrough wherein the first gate is configured such that: when the first gate is in its open position a first path is provided for product to exit the first product receiving volume and when the first gate is in its closed position the first path is closed and product may be retained in the first product receiving volume and wherein the slack removal body is configured to remain substantially stationary as the first gate is moved between its respective open and closed positions.