New crawler erection concept from Liebherr
17 October 2014
Crane manufacturer Liebherr has developed a new system for erecting its 600 tonne capacity LR 1600/2 crawler cranes with long wind power boom systems.
Instead of using a large counterweight when erecting the boom systems, Liebherr has used an LTR 1220 telescopic crawler crane as the counterweight instead. According to the manufacturer, this way is more efficient, safer and reduces the amount of ballast that has to be transported.
The new concept was shown at a customer event in August at the Liebherr-Werk Ehingen factory in Germany. For the demonstration an LR 1600/2 was configured with an SL10DFB main boom system with a main boom measuring 153 metres long and a 12 m fixed jib.
Normally to erect the boom in this configuration, 350 tonnes of derrick ballast would be required. The ballast would then be reduced to 70 tonnes for hoisting the standard wind turbine components, and then returned to 350 tonnes when lowering the boom. In total, 350 tonnes of counterweight would need to be transported to site.
Using the LTR 1220 as the main counterweight, however, would mean that only 70 tonnes of counterweight would be required for use as suspended ballast, as during the erection and lowering of the boom system, an LTR 1220 telescopic crawler crane could be used. For the demonstration, the LTR 1220 was used as a counterweight and attached to the telescopic boom using an adapter.
“The crane and ballast plate are attached to the derrick jib using a cross beam with strap loops. After the erection process the telescopic crawler crane is detached again. The remaining 70 tonnes of derrick ballast can now be used to hoist the load, for example, a machine housing,” the manufacturer said.
The hook block on the LTR 1220 remains reeved during the erection process, so that it can be quickly used again for handling components of the wind turbines or other work, a spokesperson added. Using the new method also means that if a strong wind comes up suddenly the LTR 1220 can be used as a mobile derrick ballast to lower the boom quickly and safely whatever its location, a spokesperson said.
The new erection concept from Liebherr can be used for all long boom systems up to a length of 156 m with a 12 metre fixed jib. This applies both to the new SL10 and SL13 systems and also to the existing SL4 system.