This article is part of the 2017 Renewable Energy Handbook. A complete digital version of the Handbook is here: https://goo.gl/Sg4mHO
Three areas include the:
Nacelle – Use the appropriate torque and tensioning tools for the safe assembly of bearing and blade bolted applications.
Tower – Follow the manufacturer’s guidelines when tightening bolts on tower sections. A range of torque and tension tools are available for the assembly and maintenance of tower structures.
Foundation – For offshore yaw applications, foundation bolting can be the trickiest to maintain. Typically, a range of safe and reliable foundation bolt tensioners will secure any type of bolt to any type of offshore structure. Hydraulic torque tools generally handle onshore foundation bolts.
Electric torque wrenches operate on batteries and up to 220 Vac. The output torque is adjusted by the voltage. A torque wrench is often confused with an impact wrench. However, they are completely different tools.
Bolt tensioners stretch a bolt’s stud or shaft. A hydraulic bolt tensioner makes it easier to stretch the stud and is preferred over the usage of a hydraulic torque wrench for certain applications. The method gives a consistent tension load.
A hydraulic torque wrench is the main tool for applying torque to industrial fasteners. The wrench is simple to use because it is applied right to the nut.
What are some of the battery-powered bolting systems for wind turbines?
Lithium ion batteries have significantly changed the world of industrial bolting. Today, a portable and lightweight Lithium Gun can put out as much as 3,000 ft-lbs and tighten up to 100 bolts with a single battery. These compact systems are ideal for bolting jobs in wind turbines, where the tool must be carried up tower to the nacelle. Additionally, some battery-powered bolting systems, such as HYTORC’s Lithium Series, offer onboard documentation capabilities to let users record the torque applied to each nut and export it as needed. This provides new options for quality control in maintenance and manufacturing that were previously unavailable.
However, today’s technology makes going beyond 3,000 ft-lbs with a battery-powered tool impractical because the cumbersome tool weight. For applications that require higher torque, pneumatic and hydraulic bolting systems are still the tools of choice. Pneumatic systems can go up to 8,000 ft-lbs (more is possible, but usually impractical because of weight) and hydraulic systems can go beyond 150,000 ft-lbs when
needed. An additional benefit of hydraulic systems is that they can be interconnected and locked onto the job to provide a completely hands-free, simultorc system. For large bolted joints, using multiple tools is the best way to assure even and accurate bolt load across the flange which prevents unintentional loosening over time.
With so many different bolting systems and accessories available, the simplest way to determine the best tool for the job is to have a representative from a trusted manufacturer visit your site and perform a survey of the applications in question. Once complete, it is possible to recommend a system or combination of systems that provides the highest level of efficiency and quickest return on investment.
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