The PowerBoom technology for crawler cranes from Liebherr has reached the wind power sector. This load-capacity innovation from the Liebherr plant at Ehingen made a great impression at the end of June with its first operation in actual practice in the wind power sector. In the Dutch town of Eemshaven a 1,350-ton Liebherr crawler crane, type LR 11350-P1800, equipped with the new parallel boom, lifted a machine housing of the 6 Megawatt class, belonging to Repower and weighing 340 tons, onto an installation tower 110 meters high. The gross weight with this impressive lift was no less than 378 tons!
The gondola, which at Eemshaven was hoisted aloft in its complete assembled state, may well be one of the heaviest which has ever been lifted onshore by one crane in one single lift. At least, Norbert van Schaik, Repower’s local site manager, knows of no other case in which machine housings of similar weight have been lifted by one crawler crane with just one hoisting operation. In most cases, when wind power systems are being installed, at least the drive train is lifted individually, or even a large number of the components are only fitted once the housing has been lifted and positioned.
For the wind power fitters, this new possibility of complete installation of the gondola makes their work a great deal easier. The main advantage is the time saving, thanks to there being no longer any need for the often difficult assembly of the individual components at a great height. Other powerful arguments are the shortening of the actual lifting times, and fewer waiting periods when the wind gets too strong, conditions which are both expensive and set nerves on edge. “We could of course also have carried out the assembly of this machine housing with an LG 1750, but then we would have needed several lifts, and several more days to do it”, reckons Simon Langefeld, Repower team leader on the site.
And the weather on the Dutch coast proves the experienced engineer right. After days of waiting, with the wind blowing in strong gusts, the men on the site only had a short window of opportunity with acceptable wind speeds for lifting the last tower segment and placing the gondola. And just as the machine housing, 18 meters long and seven meters high, was being secured up aloft, the wind gauge on the boom tip of the crane was already showing that the wind was getting up again. It will be another few windy days before the rotor hub and the blades can be put in place.
The “PowerBoom” parallel boom, presented last year, was originally developed by Liebherr for the LR 13000, but the innovation was then also transferred to the smaller type LR 11350. Just how immense the effect of this technology is with regard to increasing possible load capacities can be very clearly seen from the example of the equipment status of the crawler crane at Eemshaven. With the boom at a steep setting and a mast length of 144 meters, the lifting values with the parallel boom are more than 70 percent greater in comparison with the conventional single lattice boom.
The two crane drivers from the crane company Weldex, based in Ireland, are also very pleased with the new PowerBoom. Both the one-hour lift and the movement of the heavy-duty crane by about ten meters, with the load at a height under hook of 120 meters, went absolutely smoothly, with no problems at all. Brian Doherty and Mark Hall had taken it in turns in the spacious cab to work the brand new giant crane, with its excellent power and performance.
The machine purchased by Weldex was transported from Ehingen directly to the construction site on the Dutch North Sea coast, to be operated there on instructions from the clients Mammoet. A total of two “6M” systems from Repower were installed by the LR 11350-P1800 in Eemshaven, both serving as test facilities. Plans are for 48 “windmills” of this type to be installed from 2013 onwards in the “North Sea East” offshore windpark, off the island of Heligoland.