FEATURE SPONSOR
BOLTING & FASTENINGS
After many years of learning, every pedestal crane that is on an offshore platform in the British section of the North Sea is now using measurement fasteners in the main slew bearing, and quite often on the boom assembly as well.
BENEFITS
Robert de Rijcke from Kenz cranes is just one of the beneficiaries, “we can accurately determine pre-tension at installation and with these measurement fasteners we don’t have to loosen and re- tighten in our annual checks.”
It has been estimated that the maintenance savings alone on each crane range between £10,000 and £15,000 every year – and that’s just from using the fasteners on one important joint. On a wind turbine there are at least nine joints that could benefit from the same approach.
In addition, the assurance and increased performance provided by the fasteners has meant that Kenz has been able to increase the load bearing performance provided by these slew bearings in some circumstances.
DRAMATIC SAVINGS
Back in the wind energy industry, if the same measurement fasteners were employed on your typical 2.3 MW turbine, the time taken to carry out a maintenance check of all 1,000 bolts would reduce dramatically.
Three companies were questioned about the time it took them to carry out their annual bolt maintenance checks on a 2.3MW turbine…
• Company (A) stated it takes 2 men 100 hours = 200 man hours
• Company (B) stated it takes 2 men 80 hours = 160 man hours
• Company (C) stated it takes 2 men 60 hours = 120 man hours
The same turbine fitted with measurement fasteners can be checked in just two hours. The figures speak for themselves, and in offshore locations the benefits are even more dramatic.
In addition to the increased reliability and savings in maintenance, the improved performance delivered by the measurement fastener means that it is possible to significantly reduce the number of bolts in each joint without compromising integrity.
Important joints can still retain integrity with up to a 50% reduction in bolts. This reduces production costs – fewr holes, less drilling, fewer bolts and of course this also speeds up maintenance checks even more.
ENJOYING THE BENEFITS – CASE STUDIES
A relatively small number of turbine manufacturers are already enjoying the benefits of using measurement fasteners, but there are pilot projects currently being carried out on very large turbines as well. Two companies that have been using them for several years are Suzlon and Vergnet.
SUZLON ENERGY
Suzlon Energy fits the fasteners on all its 1.25 megawatt and 2.1 megawatt wind turbines. They are standard fit on the wind turbine blade connections. Vergnet are now using them on the main structural joint of their unique GEV HP wind turbines, where the two halves of the turbine nacelle are joined.
VERGNET
Vergnet’s design allows the main turbine to be quickly disassembled into two halves so that the upwind nacelle section, complete with rotors, can be lowered to the ground and easily secured. This can be either as a protective measure in extreme weather conditions, or for much quicker service and maintenance.
The measured approach to assuring bolted joint reliability and safety is a proven science in a number of other industries. Hopefully it won’t be too long before the application of these fasteners in wind energy becomes as widespread as it is in offshore pedestal cranes.
Rod Corbett James Walker RotaBolt
Click to view more info = Click to view video 1
= Click to view video
www.windenergynetwork.co.uk
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