SOIL INTAKE OF SUCTION-TUBE DREDGER FOR DIGGING UNDERWATER TRENCHES Russian patent published in 2001 - IPC

FIELD: earth moving facilities; digging of trenches in clay and sand- clay soils. SUBSTANCE: proposed soil intake has two mechanical vertical or inclined rippers, each consisting of upper and lower parts, screen and suction system. To ensure against sticking, upper parts are made as screw rippers, and lower ones, as mill rippers with cantilever blades. Surfaces of rippers in upper and lower parts are made curvilinear, antisticking, with similar angle and sense of helix of cutting profiles to provide displacement of soil along inter-turn channels only in one direction from top to bottom, to suction zone formed within the limits of location of mill ripper cantilever blades. Small amount of solid spill is provided by screen installed behind rippers which can be shifted in vertical and horizontal planes and by slot-type suction tip installed at trench sole for taking in milled and fallen soil. To form trenches of trapezoidal cross-section, soil intake is provided with slopers which should be preferably combined with screen. To provide displacement of milled soil at reduced friction, rippers can be furnished with screws provided with inter-turn channels diverging downwards. EFFECT: provision of effective soil intake without clogging with soil. 3 cl, 7 dwg