Abstract: A system for determining the effectiveness of the filtering and maneuverability of a robot for cleaning swimming pools, the robot includes a robot propelling motor, at least one water pump having an impeller and an impeller motor, a pool water inlet leading to a filter, a filtered water outlet, and a propelling mechanism for propelling the robot along the floor and/or walls of the swimming pool, the system comprising a computer for determining and setting an initial power to be supplied to the impeller motor, a first circuit for sensing the actual power supplied to the impeller motor during its operation, a second circuit for calculating the ratio between the set power and an instantaneous power supplied to said impeller motor, and a producer connected to the second circuit for producing an indication signal when the ratio exceeds a predetermined value.

Abstract: The invention provides, in combination with a swimming pool cleaning device comprising an outer shell with a detachable lid, the outer shell being open at its lower end, and an inner shell spaced apart therefrom, open at its upper end and accommodating an impeller and a clean-water exit tube, the improvement comprising a filter element having a basket-like shape including a tubular central stem configured to be seated on the exit tube, the central stem being surrounded by an annular trough constituting the active filtering portion of the element, with the outer rim of the trough being detachably affixed to the inner shell, wherein, during operation of the device, solids-entraining water drawn by the impeller enters the annular trough from above and, passing the active filtering portion, emerges therefrom as clean water to be expelled through the exit tube and returned to the pool.

Abstract: An underwater navigation and control system for a swimming pool cleaning robot, having a driver, an impeller, a filter and a processor for controlling the driver and a signal-producing circuit. The system further includes a signal-detecting circuit mounted on the pool, an interface located on the ground in proximity to the pool and comprising a detector for receiving and processing data from the detecting circuit and for transmitting signals to the robot's processor. Determination of the actual robot location is performed by triangulation in which the stationary triangulation base is defined by at least two spaced-apart signal detectors and the mobile triangle apex is constituted by the signal-producing circuit carried by the robot.