Hydraulic system for opening and closing hopper barges

Abstract

A hydraulic system for opening and closing hopper barge comprises at least one and preferably two fluid pressure cylinders which are adapted to be positioned on one of the barge parts and a piston which is slidable in the cylinder which is adapted to be connected through its piston rod to the other barge part. The cylinder is connected by a first conduit at its piston rod end and by a second conduit at the opposite end, and a pump and a return line are connected to the respective first and second conduits. A pilot valve is located in the first and second conduits and includes three separate positions. In one position a pump discharge is connected to one end of the cylinder and the other end is connected to the return, and in another position, the opposite is true. In a third position, the first conduit is connected to a check valve and the pump discharge is connected to a return line in order to short circuit the pump. One end of the cylinder, for example one having the first circuit, is provided with a check valve arrangement which permits the piston to be locked in its position in the cylinder, preventing return flow except upon the occurrence of a predetermined excess of pressure. The check valves permit relief of the pressure throughout the connective system. Before the check valve locking system is opened, the pressures lines to the associated piston are checked by an electrohydraulic pressure switch, and for this purpose a second pilot valve is connected in the first and second conduits for selectively connecting them to the pressure side of the pump or the return line.