In-line centrifugal pump

Apparatus for use on a hydraulic dredge for providing positive pressure at the inlet of a main dredge pump on a barge comprising:

• a ladder extending downwardly from the bow of said barge;
• a suction pipe extending from said main pump and downwardly along said ladder, said suction pipe having a mouthpiece proximate a lower end of said ladder;
• a housing disposed in line with said suction pipe at a position proximate said mouthpiece and having means defining an inlet and outlet, said inlet and outlet defining first and second directions being displaced by an angle relative to one another of less than approximately 90.degree.;
• and
• an impeller having a predetermined outer diameter mounted within said housing for preferred sense rotation about an axis perpendicular to said first and second directions, said preferred sense of rotation being such that fluid flowing from said inlet to said outlet along the direction of rotation of said impeller covers an arc subtending said angle of less than approximately 90.degree..

In a dredge including a barge, a ladder extending downwardly from the bow of said barge, a cutter at a leading end of said ladder, a main pump on said barge, a suction pipe extending from said main pump and downwardly along said ladder, said suction pipe having a suction mouthpiece proximate said cutter head, an improved ladder pump situated on said ladder mounted in-line within said suction pipe and at a position proximate said suction mouthpiece, said ladder pump comprising:

• a housing;
• an impeller of predetermined outer diameter mounted within said housing for preferred sense rotation about a normally horizontal axis transverse to said ladder;
• means on said housing defining an inlet for fluid flow along a first direction perpendicular to said axis;
• and
• means on said housing defining an outlet for fluid flow along a second direction perpendicular to said axis, said second direction defining a deflection angle relative to said first direction of less than approximately 90.degree., said preferred sense of rotation of said impeller being such that fluid flowing from said inlet to said outlet along the direction of rotation of said impeller covers an arc subtending said deflection angle;
• wherein said housing has inner dimensions defining a substantial radial clearance around said impeller over a portion of said impeller's travel extending from said inlet to said outlet along the direction of rotation of said impeller.