Abstract: A sluice arrangement for sluicing out clinker and uncombusted residue from combustion furnaces such as rotary kilns and the like. A steel plate duct having a cross-section at least equal to that of an ash pit is attached to the lower end of the ash pit in a downwards steeply slanting position and is provided with an upper and lower mechanically operated swinging flap. By manually or automatically controlling the closed/opened positions of the flaps relative to each other an effective sluice is provided. A pilot system for the sluice wherein the motive power for operation of each of the flaps is controlled by separate changeover devices is also provided wherein the changing over effects the required closing/opening sequence of the flaps to provide an effective sluice.