Portal Crane System

Portal crane control systems generally employ AC variable frequency speed regulation, PLC control, and can be equipped with intelligent "status monitoring and control systems." Currently, many docks are also undertaking unmanned control retrofits for portal cranes and have achieved some success.

Portal crane mechanisms mostly employ horizontal luffing systems.

(1) The center of gravity of the load and the boom system experiences almost no vertical displacement during luffing. One method is to add a movable counterweight to balance the change in the combined center of gravity during boom pitching. This method is convenient to arrange, reliable, and widely used. Another method relies on the structural characteristics of the boom system to ensure that the trajectory of the combined center of gravity during luffing is close to a horizontal line, without a movable counterweight.

(2) The lifted load moves along a near-horizontal trajectory during luffing. Compensation and combined boom methods can be used. The compensation method involves a special rope storage system that automatically retracts and extends the corresponding lifting rope during luffing to compensate for the vertical displacement of the lifting device caused by boom lifting. The combined boom method relies on the mechanical characteristics of the combined boom to ensure that the boom tip moves nearly horizontally during luffing. Both methods are widely used.