Introduce the application knowledge of gantry cranes.

　　The gantry crane, also known as a portal crane, is a derivative product of the bridge crane, primarily used in large outdoor cargo yards and bulk material sites. Its appearance is that of a large metal frame, with the main beam of the gantry crane running horizontally. Below the main beam, two steel structural supports provide support, allowing the main beam to bear heavy loads effectively.

　　When there are special needs, tracks can also be installed at the bottom of the supports to allow large cargo to be displaced. The ends of the main beam can also be equipped with extended cantilever arms. Compared to hydraulic gantry cranes, gantry cranes have a higher utilization rate of space, a larger working range, a wider applicability, and stronger versatility. They are widely used in ports and large cargo yards.

　　Gantry cranes (portal cranes) can be categorized into many types based on their different uses, working environments, and industrial demands. The most common gantry cranes can handle various large items, bulk goods, and generally have a lifting capacity of under 100 tons, with a span between the two supports ranging from 4 to 38 meters. Common types of gantry cranes include hook cranes, grab cranes, electromagnetic cranes, and hoist gantry cranes, as well as semi-gantry cranes.

　　In large hydropower stations, large gantry cranes are often used, but their function differs from that of general gantry cranes. They are mainly used for lifting and opening gates, and can also perform installation tasks. Compared to general gantry cranes, the lifting capacity of hydropower station gantry cranes can reach 80 to 500 tons, but the span between the two supports is relatively small, only 8 to 16 meters, with lifting speeds of 1 to 5 meters per minute. Although these gantry cranes are not frequently used, their work is quite heavy when they are.