Gantry Crane Knowledge-You Must Know
Mar 25, 2025
Gantry cranes consist of lifting, slewing, luffing, and traveling mechanisms. The first three mechanisms are installed on the rotating part and participate in operations during each cycle. The rotating part is also equipped with a tilting single boom or combined boom that can be pitched and a cab. The traveling mechanism is installed at the bottom of the portal and is used to adjust the working position of the crane. For portal cranes with grabs, additional equipment such as telescopic funnels and belt conveyors is installed to increase productivity when handling bulk materials with grabs. In addition to electrical protection devices, they are also equipped with lifting capacity or lifting moment limiters, crane rail clamps, and other safety devices.
Single Girder Gantry Crane
Double Girder Gantry Crane
Classifications of Gantry Cranes
1. Portal cranes for loading and unloading: Mainly used in ports and open-air storage yards, they are equipped with grabs or hooks for loading and unloading. The lifting capacity generally does not exceed 25 tons and remains constant regardless of the working radius. They have a relatively high working speed, so productivity is often a key indicator.
2. Portal cranes for shipbuilding: Primarily used on slipways, floating docks, and outfitting sites, they are used for tasks such as hull assembly and equipment outfitting, with hooks as the lifting gear. The maximum lifting capacity can reach 300 tons, but it decreases as the working radius increases. They have multiple lifting speeds, allowing for faster lifting when handling lighter loads. Some working mechanisms are equipped with micro-movement devices to meet installation requirements. Larger portal cranes can handle greater lifting heights and larger working radii, but their working speed is lower and productivity is not as high.
3. Portal cranes for construction and installation: Mainly used in hydropower stations for tasks such as dam pouring, equipment and prefabricated component lifting, and are typically equipped with hooks. Their lifting capacity and working speed generally fall between the first two types of cranes. They feature good overall disassembly, assembly, and transportation capabilities, a large hook-lowering depth, and the ability to adapt well to temporary work and operations on trestles.
Selection Method of Gantry Cranes
Selection of Single-girder and Double-girder Gantry Cranes
Generally, for a lifting capacity of less than 50 tons and a span of less than 35 meters, without special usage requirements, a single-girder gantry crane is preferred. If a larger leg width, higher working speed, or frequent lifting of heavy and long items is required, a double-girder gantry crane is recommended.
Span and Overhang Length
The span of a gantry crane is a crucial factor affecting the crane's own weight. During selection, under the condition of meeting the equipment usage requirements and conforming to the span series standards, the span should be minimized as much as possible.
Principles for Determining Wheelbase
It should meet the stability requirements of the gantry along the crane track direction;
The shape and size of the goods should be able to pass through the steel frame of the leg plane smoothly;
Determination of Gantry Crane Spacing Dimensions
During operation, there should be a certain space dimension between the external dimensions of the gantry crane and the goods and vehicle channels in the storage yard to facilitate loading and unloading operations. Generally, when vehicles are loading and unloading within the span, they should maintain a distance of more than 0.7 meters from the legs. When the lifting gear is not in use, it should maintain a distance of more than 0.5 meters from the vehicles. When goods pass through the legs, there should be a distance of more than 0.5 meters.
How can you prevent rust on gantry cranes?
For gantry cranes that have been idle for a long time, rust prevention is a very important task. So how should they be rust-proofed when they are idle for a long time?
1. First, when the equipment is to be shut down for maintenance, the entire surface of the equipment must be inspected. It is best to ensure that all areas are covered with surface paint.
2. If during the inspection process, it is found that the paint film on some parts of the metal structure is damaged, these damaged areas must be cleaned thoroughly and then coated with anti-rust paint or other anti-rust coatings. This protects the metal surface from corrosion due to weather conditions such as rain or snow.
3. During the rust prevention process, do not neglect the moving parts of the crane, which are very crucial. For these parts, -10 or -20 grade diesel can be used for brushing. This not only removes substances that can cause corrosion to the equipment but also forms an oil film on the metal surface, protecting against low temperatures.
4. In addition to cleaning and lubricating with diesel, a layer of lubricating oil should also be applied. It is best to choose calcium-based or lithium-based grease, as they have good effects on maintaining the machinery's performance in all aspects. These greases are also relatively easy to remove when the equipment is used again.
