Improved pump-type sludge dredging apparatus

Claim 1

A dredging apparatus for removing sludge on a water bottom comprising: (A) a pump dredger having a ladder assembly, said ladder assembly being pivotally supported at its one end at a fulcrum mounted to said pump dredger with its other end movable in water; (B) a sludge suction pump provided in at least one of said ladder assembly and said pump dredger; (C) a suction pipe connected at its one end to said suction pump and extending to the movable end of said ladder assembly; and (D) a suction unit pivotally mounted through a pin at a portion of said movable end of the ladder assembly and having the other end of said suction pipe connected thereto, said suction unit comprising: (a) a main body essentially composed of a cover or flat plate member and two side walls altogether arranged in a sectional configuration substantially corresponding to an inversed U-letter shape in a direction perpendicular to the longitudinal direction in which the ladder assembly extends from the pump dredger; (b) a hood-like member expanded or flared toward below and secured at a central portion of said cover member of the main body in communication with the suction pipe, defining an opening for collecting diluted sludge therein and guiding the same into the pipe; (c) a rotatable member comprising a rotatable shaft and vanes mounted thereon, the axis of said rotatable member being directed substantially perpendicular to the face of said side walls of the main body, said rotatable shaft being disposed below said hood-like member; (d) a sludge collector means disposed between the hood-like member and the rotatable member and having a structure corresponding to a cylindrical container longitudinally with a portion thereof removed away, formed by a curved surface plate and two end plates respectively disposed at a longitudinal end, said sludge collector means being rotatable coaxial with said rotatable member; (e) a sludge inlet formed below the hood-like member for taking sludge into a lower portion of the hood-like member by means of the rotary movement of said curved surface plate of the sludge collector means; and (f) a movable vane member forming an upper wall of said sludge inlet and having a hollow arcuate configuration in longitudinal section; whereby as the suction unit is moved either forwardly or backwardly the dredging of sludge is carried out.