A sand bypass separator is provided for separating particulate matter from a fluid mixture in a production well and directing the separated particulate matter away from a pump intake. The separator includes an outer tube, an inner tube positioned within the outer tube. The outer tube has a plurality of slots to allow the fluid mixture to enter the separator between the outer tube and the inner tube. As the fluid mixture moves downward, the fluid mixture reaches a downward velocity sufficient to allow the particulate matter in the fluid mixture to continue downward as the fluid is drawn into the inner tube through the pump intake. A bypass that extends from above the pump intake to below the pump intake to collect and direct the separated particulate matter separated below the pump intake may also be included.

A sand bypass separator is provided for separating particulate matter from a fluid mixture in a production well and directing the separated particulate matter away from a pump intake. The separator includes an outer tube, an inner tube positioned within the outer tube, and a bypass. The outer tube has a plurality of slots to allow the fluid mixture to enter the separator between the outer tube and the inner tube. As the fluid mixture moves downward, the fluid mixture reaches a downward velocity sufficient to allow the particulate matter in the fluid mixture to continue downward as the fluid is drawn into the inner tube through the pump intake. The bypass extends from above the pump intake to below the pump intake to collect and direct the separated particulate matter separated below the pump intake.

A drum (100) for sorting objects is provided. The drum has a cylindrical shape, and said drum (100) comprises a cylindrical body (101), with an inner and an outer envelope surface. A plurality of pockets (104) are arranged on the inner envelope surface of the cylindrical body (101), and said pockets (104) are provided with openings (105) opening up into the outer envelope surface. At least one groove (106) is arranged on the outer envelope surface, said groove (105) interconnecting at least two openings (105). A machine (1000) comprising such a drum (100) and a method for manufacturing such drum (100) are also provided.

A device for concentrating an object to be treated has a filter body in which a movable plate is disposed between adjacent annular fixed plates, the moveable plate being formed in the same annular shape. Sludge filtrate passes through filtrate inflow gaps between the fixed plates and the movable plate before being caused to flow into the filter body. The movable plate is moved so that solids in the sludge are kept from clogging the filtrate inflow gaps. A cleaning member is caused to rub against the outer peripheral surfaces of the fixed plates so that solids adhering to the outer peripheral surfaces of the fixed plates are scraped off. The movable plates of said device are caused to perform a circular movement by eccentric cams fixed to the shaft. The cleaning member is fixed to the shaft, and caused to rotate around the shaft by the rotation of the shaft so that solids adhering to the outer peripheral surfaces of the fixed plates are scraped off.