for cranes and material handling technology. Material handling in maritime ports is subject to tough conditions. Performance is key, time is of the essence. High port fees demand high efficiency un- and reloading of container ships. Thus, functionality and reliability of material handling device in ports is key to efficiency. Kabelschlepp has developed a unique energy management solution for port cranes and other applications. Combined with an intelligent emergency system, even the worst case scenario of a down time can be reduced to a minimum.
Modern port cranes allow 500 meter travel, or more. This is a challenge for energy and data management systems. A conventional drag chain gliding arrangement is subject to wear due to the high friction involved, very long travels are almost impossible to realize. Kabelschlepp has now chosen a different approach: rolling instead of sliding.
The innovative RCC cable carrier system does not need the upper half of the chain gliding on the lower half. The chain travels on ball bearing castors running on a support trough, which is easy to fit. The upper part of the chain runs in the upper trough, the lower part is laid in a lower trough. The castors run into U – shaped notches, holding them in position despite minor link tolerances in the chain. This supported guidance prevents the cable carrier from sagging even in extreme travels and high continuity operation. Push and pull forces are reduced by 90 % which reduces the power requirements for the drive.
Due to the reduced push forces and the low friction there is no danger of the chain rising. In addition the design of the guide rail itself prevents the chain from rising by turning in the top edge. Another advantage over the gliding arrangement is that RCC minimizes wear and reduces maintenance requirements – In gliding applications material in contact creates regular need for maintenance such as changing glide shoes.
A real bargain
Reduced chain wear, improved cable protection and the extended service life (no rear bend needed as in gliding arrangements) are a direct result of clever design and guide trough to fit straight at connecting height. These advantages reflect in the system cost.
Furthermore, there is no overhang (depot) – the gliding application needs to loop back and this additional length exceeds the required travel. By offering standard connection height RCC has minimized the loop – saving room, as well as budget by shorter chain and cable.
The system also features a quiet, low vibration operation and allows high travel speeds up to 10 m/s as well as additional loads up to 50 kg/m. It is suitable for use with proven standard energy chains.
Clever emergency system to prevent collision course
To complete the Rail Cable Carrier Kabelschlepp has now developed the Emergency Cable Carrier: a decoupling system with emergency lock, preventing energy and data cuts in case of the system blocking. The intelligent ECC decoupling system reduces cost intensive down- and maintenance times, as can be demonstrated in the following scenario:
Hamburg Container Terminal. A large container vessel is docked. Landing fees of some 100 K€ require fast un-and reloading. But the lading is stopped by a defect container crane. An obstacle blocked the travel of the energy management system, resulting in a crash. Carrier damaged, cables snapped, crane static. This is a costly incident for any port management, reliable technology being a significant key to efficiency.
Material handling in port areas requires intelligent and flexible solutions – just like the ECC. It was developed not only for long travel in port handling, but also for harsh environmental conditions like in coal power plants and steel mills. These are application conditions where it is likely that objects block the travel of the energy management system, which as a consequence cannot move freely. Push or pull forces get excessive, the energy management system clogs or tears, the damage paralysing the entire handling device.
The Kabelschlepp decoupling system consists of a main carrier chain and an emergency carrier chain. The system recognizes a blockade triggered by an obstruction of travel in either push or pull direction, and stops the device immediately. This stop is triggered when the permissible force to the trailing arm of the main chain is exceeded. However the momentum of the moving masses in these applications is high – the dynamic system and its pay load – and the application will likely travel a distance after an emergency stop is released.
This is why the energy management system is equipped with an emergency carrier bridging this momentum. The emergency carrier is located in a cart traveling with the trailing arm in normal operation. In case of an emergency stop the main chain stops and the emergency chain de couples to travel on
There is no damage after the crash, after removing the obstacle the system is reconnected to the main chain for continuing operation. The device can be re commissioned after a brief interruption. This means maximum security and minimized down times and reduced cost – not only for port management companies.