The international crane business had to critically review its longstanding development strategies in light of the 2009 worldwide recession. This particularly impacted worldwide transport of cargo by containers. Based on an important extension of globally operated sea terminals, national networked domestic ports and goods distribution hubs, the focus is currently on the modernization of technology already in operation. There is also an increasingly strong orientation towards consolidating total terminal costs, and for reducing environmental pollution as a result of container terminal operations.
On account of these new challenges, the crane operators and crane manufacturers have intensified the installation of optimized and custom-made technical solutions. This also means a special challenge for the supplying industry. On one hand, optimization processes must be found for the modernization of the existing technologies. However, on the other hand, a critical review of the technical solutions that have been the standard so far is required. The objective is minimizing the capital expenses and operational costs in order that they are adjusted to the new international environmental standards. Due to the particular impact of energy and data transmission systems on the functional reliability and cost efficiency of container cranes, their modernization and optimization will be important for safeguarding the future of container terminals operating advanced technology.
Solutions for flexible energy and data transmission
The Conductix-Wampfler group accompanies this process of technical and organizational modernization in the terminals through early and determined development of new techniques and technologies in the field of energy and data transmission systems for container cranes. Depending on the position of the interface to the crane and on the crane itself, there could be new concepts for modernization of existing crane techniques and manufacture of new container cranes.
Especially in the field of crane feeding for STS container cranes and for RMG, advanced and novel Conductix-Wampfler solutions of the electronic controls for motorized cable reels provide a technically sophisticated application of the reel technique. With the application of mobile (oscillating) cable guides (see Figure 1), the tensile forces will be determined by their position and always be held contemporarily by the custommade drive control (Sinamics/AC800M) in the area of the permissible cable tensile force. So it will be possible, even with the feeding point in the center, to pass it smoothly at high speed without any reduction.
At the interface of the STS container crane, between crane control and main trolley supply, advanced components for the heavy duty cable festoon systems can be applied. The increased use of modern STS container cranes, with rope-driven technology for travel, and hoist movement of the main trolley, has produced a rigorous reduction of transfer demands on energy and control signals between crane and main trolley.
There are currently high speed festoon systems available for speeds up to 250 meters per minute, with standardized drive versions. Depending on the operation conditions and length of travel, the distance of the main trolley is up to 180 meters. The inclusion of a second mechanical drive section, by means of the catenary towing trolley, or alternative, and the installation of partially arranged additional electromotive drives, will significantly harmonize the dynamic course of motion in the cable loops.
These additional drives (see Figure 2), together with advanced frequency inverter drive control by Conductix-Wampfler, will produce a very gentle and low-wear operation and movement of the high cost cable packages. With these special motorized cable trolley systems, average operating lifetimes of more than 12 years can be achieved, even during extreme crane operation.
In order to be able compensate the differing qualities in the accuracy of the assembly on the cable trolley track, special chassis with asymmetric arrangement of the rollers can be installed, if required. This technique has proved particularly valuable on highly loaded, high speed cranes, with a technically insufficient layout of track. Generously dimensioned rollers, in combination with the inherent travel characteristics, will make the required drive forces for the festoon system much more favorable than on a comparable installation on energy guiding chains.
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