Abstract: A grab bucket, in particular motor-driven underwater grab bucket, has first and second half-scoops. The scoops can be moved relative to on another from an open position into a closed position by a hydraulic cylinder. The opening angle of the half-scoops is monitored by a sensor which is connected to a control and monitoring device. The sensor is integrated in the hydraulic cylinder and generates an actuating-travel signal which corresponds to the actuating travel of the hydraulic cylinder.

Abstract: A device for washing out and classifying organic, clay-like and other impurities from gravel, comprising a charging chute for feeding material into a washing trough. The washing trough comprises a conveyor belt designed to move in a direction perpendicular to the direction of the flow of material and a plurality of shower devices designed to act against the direction of travel of the belt. The conveyor belt is supported by a series of support rollers and tension rollers.

Abstract: A device for classifying superfine material from continuously fed granular solids which has a charging chute feeding the material into a washing trough. The washing trough is formed by a conveyor belt, which is mounted on a machine frame. A part of the conveyor belt forms the washing trough downstream of the charging chute. Another part of the conveyor belt is arranged below the charging chute, and is elevated against the direction of flow of the charged material. The charging chute has a false bottom above the washing trough and in the material feed area. The false bottom is adjoined by a gap on the head end of the washing trough. The gap extends over the entire width of the trough. The remaining area of the charging chute is perforated. In another embodiment, a vat is arranged at the end of the washing trough and extends over the entire width and depth of the washing trough. The vat has a flow of liquid passing over it and is filled with spherical elements of different shapes, sizes and surfaces.