Abstract: A control system is disclosed for a dredging device which includes a submersible pump having one or more chambers. Each chamber defines an air port through which air can be delivered to and exhausted from the chamber, a material discharge port for discharging liquid and solid material from the chamber, and a chamber suction port for admitting liquid and solid material to the chamber. Air control valves are provided for alternately exhausting air from each chamber to admit material to the chamber through the suction port and for delivering air to each chamber so as to discharge material from the chamber through the discharge port. The control system operates these air control valves in accordance with a selectable timed cycle to achieve optimum efficiency in the dredging operation.

Abstract: An efficient dredging device is disclosed, which includes a submersible pump having one or more chambers. Each chamber defines an air port through which air can be delivered to and exhausted from the chamber, and a material discharge port for discharging liquid and solid material from the chamber. A check valve is associated with the discharge port to prohibit the return of discharged material to the chamber. A chamber suction port admits liquid and solid material to the chamber, and a check valve prohibits the escape of material from the chamber through the suction port. Air control means are provided for cyclicly exhausting air from the chamber to admit material to the chamber through the suction port, and for delivering air to the chamber so as to discharge material from the chamber through the discharge port. A rotatable cutter member cuts material to be dredged, and pipes connect the cutter to the chamber discharge port.