GB1422021A - Suction dredger - Google Patents

Abstract

1422021 Taking up slack in flexible elements GOYO-BALLAST CO Ltd 29 Jan 1973 [28 Jan 1972] 4341/73 Heading B8B [Also in Divisions E1 and E2] A cable 8, which is used to suspend a flexible suction conduit 3 from a dredging vessel, passes over a pulley 21 mounted on a piston 20 which moves within a cylinder 17 in response to sealevel movements; a control mechanism being provided to sense movement of the piston outside predetermined limits and to reverse such movement by supplying fluid to or discharging fluid from the hydraulic circuit of the cylinder 17. Inductive sensors 27, 28 detect movement of a rod 31 on the piston and send signals representative of magnitude and direction of piston movement to control circuitry 43 (Fig. 2, not shown) which operates valve 40 or 41 to release fluid from or admit fluid to the cylinder. A cable winch drum 13 is controlled via devices 47, 48 by the circuitry 43 to prevent movement of the winch drum which would conflict with the corrective movement being induced in the piston. However if sea level movements exceed a second higher set of limits the circuitry causes reverse movement of the winch drum to supplement the corrective action of the piston.