The invention relates to a system and method for separating pieces having a second density (9c) from granular material. The system includes a separation tank (2) comprising a first side wall (12) provided with a tank outlet (6), a bottom (7), a pipe (4) defining a channel (3a) for allowing a slurry to enter the tank (2). A pipe outlet (4b) is spaced apart from the tank outlet and arranged vertically below the outlet (6). The separation tank (2) comprises a trap (5) for collecting said pieces. A separation chamber (8a) is arranged in liquid communication with the pipe outlet to allow slurry to enter the separation chamber. The pipe outlet is in a lower third of the separation tank facing the bottom of the tank so that slurry flows vertically through the pipe outlet towards the bottom causing a turbulent flow of the slurry in the tank.

A method and apparatus for washing sheets of plastic material originating from industrial and agricultural waste, for subsequent reuse thereof as a raw material. The sheets of plastic material, precut into soiled pieces of large dimensions, and a water flow are supplied to a washing tank containing a water bath; a screw stirrer generates intense stirring of the water bath and recirculation, inside the tank, of the soiled plastic pieces that causes the contaminating material to be detached and separated by sedimentation from the plastic pieces. The cleaned pieces of plastic material of large dimensions, devoid of contaminant, which float in the water bath are removed by dragging, in a floating condition, along a discharging channel by the combined action of a dragging device and of a water flow that exits the washing tank; the dragging device, consisting of an endless belt, extends from one side of the washing tank along the discharging channel, supported in a freely tiltable manner.

A method and apparatus for washing sheets of plastic material originating from industrial and agricultural waste, for subsequent reuse thereof as a raw material. The sheets of plastic material, precut into soiled pieces of large dimensions, and a water flow are supplied to a washing tank containing a water bath; a screw stirrer generates intense stirring of the water bath and recirculation, inside the tank, of the soiled plastic pieces that causes the contaminating material to be detached and separated by sedimentation from the plastic pieces. The cleaned pieces of plastic material of large dimensions, devoid of contaminant, which float in the water bath are removed by dragging, in a floating condition, along a discharging channel by the combined action of a dragging device and of a water flow that exits the washing tank; the dragging device, consisting of an endless belt, extends from one side of the washing tank along the discharging channel, supported in a freely tiltable manner.

An apparatus for processing wet aggregate material includes a trough mounted at an inclined angle and a pair of parallel shafts being rotatably mounted within the trough. Each shaft has a plurality of agled blades mounted thereon so that the blades carry aggregate material within the trough towards an upper end of the trough when the shafts are rotated. At least one weir is provided in a side wall of the trough adjacent a lower end thereof, through which excess water and any floating trash within the trough may pass. Fluid outlets provided in the trough communicate with a fluid supply such that fluid exiting from the fluid outlets creates an upward flow in the trough pushing particles of light material, organics and floatables to the top surface of the water to pass out of the trough via the at least one weir.

An apparatus for processing wet aggregate material includes a trough mounted at an inclined angle and a pair of parallel shafts being rotatably mounted within the trough. Each shaft has a plurality of agled blades mounted thereon so that the blades carry aggregate material within the trough towards an upper end of the trough when the shafts are rotated. At least one weir is provided in a side wall of the trough adjacent a lower end thereof, through which excess water and any floating trash within the trough may pass. Fluid outlets provided in the trough communicate with a fluid supply such that fluid exiting from the fluid outlets creates an upward flow in the trough pushing particles of light material, organics and floatables to the top surface of the water to pass out of the trough via the at least one weir.

A particle separator is disclosed for a first fluid that includes solid particles of different sizes dispersed therein includes a flow path of the first fluid. A chamber is disposed below the first fluid flow path. The chamber includes an open upper portion adjacent to and below the first fluid flow path. A second fluid at a second density greater than the first density is disposed in the chamber. The second fluid is in contact with the first fluid flow path at the chamber open upper portion.

A particle separator is disclosed for a first fluid that includes solid particles of different sizes dispersed therein includes a flow path of the first fluid. A chamber is disposed below the first fluid flow path. The chamber includes an open upper portion adjacent to and below the first fluid flow path. A second fluid at a second density greater than the first density is disposed in the chamber. The second fluid is in contact with the first fluid flow path at the chamber open upper portion.

A method for washing and separating pieces of plastics material from contaminating material that also includes metal elements, comprises the steps of: supplying, to a washing container, a washing fluid, having a first specific weight value , and the pieces of plastics material joined to the contaminating material; driving, in the washing container, a stirring arrangement provided with blades for generating in the washing fluid a turbulent stirring action to remove from the plastics material, through mechanical action, the part of contaminating material adhering thereto. The tilt of the blades and the rotation speed of the stirring arrangement are chosen carefully to generate a thrusting action upwards so as to maintain in a floating condition the plastics material with a specific weight that is greater than the specific weight of the fluid; the force of the thrusting action is limited to a value that is such as not to hinder the downward precipitation of the contaminating metal elements that have a further specific weight value that is greater than the aforesaid second value. The plastics material is retained inside the container for sufficient time to obtain a desired degree of purity and decontamination for the plastics material, after which it is evacuated by controlled overflow. The heavy contaminating material, in particular the metal elements that accumulate on the bottom, are periodically evacuated by a device of valve or pump type. The apparatus for implementing the aforesaid method is also disclosed.

Method for washing a plastics material and for separating contaminating substances therefrom comprises the steps of: supplying a first flow of a washing fluid together with the plastics material with contaminants to a washing container in which a stirrer generates a turbulent action to detach mechanically the contaminants adhering to the plastics material, enabling a first fraction of heavier contaminants to precipitate onto a first bottom portion of the container, thus performing a first action of separating contaminants; transferring a second flow: of fluid with floating plastics material from the container to a first separating chamber, in which a second separating action takes place with the precipitation of a second fraction of the contaminants onto a second bottom portion of the first chamber; conveying a third flow of fluid with floating plastics material from the first chamber to a second separating chamber and evacuating by overflowing an outgoing flow of fluid together with the processed plastics material; in the transit froth the first chamber to the second chamber the agglomerates of floating plastics are disaggregated, and to the third flow and to the plastics material a downward propelling action inside the second chamber is imparted to promote a third separating action with precipitation of a third fraction of the contaminants onto a third bottom portion of the second chamber; removing from the second chamber a recirculation flow comprising precipitated fluid and contaminants and sending the recirculation flow to a screen unit that retains the contaminants, returning the washing fluid to the first or second chamber. The apparatus for implementing the aforesaid method is also disclosed.

A method and apparatus for washing sheets of plastic material originating from industrial and agricultural waste, for subsequent reuse thereof as a raw material. The sheets of plastic material, precut into soiled pieces of large dimensions, and a water flow are supplied to a washing tank containing a water bath; a screw stirrer generates intense stirring of the water bath and recirculation, inside the tank, of the soiled plastic pieces that causes the contaminating material to be detached and separated by sedimentation from the plastic pieces. The cleaned pieces of plastic material of large dimensions, devoid of contaminant, which float in the water bath are removed by dragging, in a floating condition, along a discharging channel by the combined action of a dragging device and of a water flow that exits the washing tank; the dragging device, consisting of an endless belt, extends from one side of the washing tank along the discharging channel, supported in a freely tiltable manner.