轮机英语【轮机长】

考试试题

[问答题]A two-ram hydraulic gear consists of a hydraulic ram situated on the port side of the tiller and another ram on the starboard side, linked at their outer ends to the tiller arm by a crosshead and swivel block, the other ends of the rams working inside their own hydraulic cylinders and pipes connect these cylinders to a hydraulic pump. The tiller is firmly keyed to the rudder stock. The pump is of special construction and may be axial or radial design. The pump runs continuously in the same direction driven by an electric motor, and the position of a movable plate or a floating ring inside the pump controls the suction and discharge of the oil. When the plate or ring is in mid position, no oil is drawn; when the plate or ring is moved in one direction from mid position, oil is drawn from one cylinder and discharged into the other; when the plate or ring is moved in the opposite direction, the suction and discharge of the oil is reversed in direction. The plate or ring is actuated by a control rod which is attached at its outer end o the hunting gear. A four-ram hydraulic steering gear may be fitted in large ships for greater steering power, instead of the tow-ram type. It is simply a double tow-ram unit, so that the force of tow diagonally opposite rams can act on the tiller to produce double the turning effect. The pump control is moved by the telemotor through a floating lever. The other end of this lever is connected through a safety spring link to the rudder stock or tiller. The telemotor is the receiver of the hydraulic remote control system from wheel on the bridge. The linkage through the floating lever of telemotor, pump and rudder stock forms the hunting gear.