Abstract: The invention relates to a method and an apparatus for cleaning the sand beds of slow sand filters, infiltration basins and pools of other types having sand beds in water treatment works and similar plants, while the filter is in service, by removing a few centimeters of the bed surface, cleaning the sand of the sludge or filter film formed on the bed surface, returning the cleaned sand to the bed, and discharging the separated sludge, suspended in water to drain or to a suitable disposal site. This is achieved using a tracked cleaning machine equipped with a submersible pump (7) and nozzle (8) to remove the top layer of sludge-bearing sand from the bed, cleaning the sludge from the sand thus removed in a hydrocyclone (13), returning the cleaned sand to the bed via a spreader plate (15) and discharging the water-suspended sludge to a drain or to a suitable disposal site through a hose (17).

Abstract: The invention relates to a method and an apparatus for cleaning the sand beds of slow sand filters, infiltration basins and pools of other types having sand beds in water treatment works and similar plants, while the filter is in service, by removing a few centimeters of the bed surface, cleaning the sand of the sludge or filter film formed on the bed surface, returning the cleaned sand to the bed, and discharging the separated sludge, suspended in water to drain or to a suitable disposal site. This is achieved using a tracked cleaning machine equipped with a submersible pump (7) and nozzle (8) to remove the top layer of sludge-bearing sand from the bed, cleaning the sludge from the sand thus removed in a hydrocyclone (13), returning the cleaned sand to the bed via a spreader plate (15) and discharging the water-suspended sludge to a drain or to a suitable disposal site through a hose (17).

Abstract: The invention relates to a method and an apparatus for cleaning the sand beds of slow sand filters, infiltration basins and pools of other types having sand beds in water treatment works and similar plants, while the filter is in service, by removing a few centimeters of the bed surface, cleaning the sand of the sludge or filter film formed on the bed surface, returning the cleaned sand to the bed, and discharging the separated sludge, suspended in water to drain or to a suitable disposal site. This is achieved using a tracked cleaning machine equipped with a submersible pump (7) and nozzle (8) to remove the top layer of sludge-bearing sand from the bed, cleaning the sludge from the sand thus removed in a hydrocyclone (13), returning the cleaned sand to the bed via a spreader plate (15) and discharging the water-suspended sludge to a drain or to a suitable disposal site through a hose (17).

Abstract: The invention is directed to an apparatus for cleaning the bottom and sides of a water-filled pool with an automatic pool cleaner equipped with motor-driven track belts (9a, 9b) and with a poolside programming module to control the cleaning method. The pool cleaner is equipped with two counter-rotating brush rollers (14a, 14b). Each brush roller is provided with a longitudinal shield (17a, 17b) which partly encloses the brush roller and is sealed against the pool cleaner chassis (1) to increase the water velocity generated by the pool cleaner pump impeller (4) thereby increasing the suction developed between the pool cleaner suction box (8) and the pool bottom or side walls, as applicable, to achieve more efficient cleaning and to ensure the travel of the pool cleaner, particularly along the side walls of the pool.