OFFSHORE WIND FARMS & RENEWABLES
Maintenance-Free-Bolting Concept for Bolts up to M80 (3 1/8")
Maintenance-Free-Bolting concept by ITH
Bolting Technology: IHF bolts, IHF Roundnuts, and digital monitoring and application
management for ITH Bolt Tensioning Cylinders.
ITH Bolting Technology combines digital bolting tool procedures, advanced fastener design, and installation know- how to reduce maintenance costs significantly – proven for onshore and offshore wind- turbine installation projects.
ITH Bolting Technology is a leading global system supplier in bolting technology providing bolting tools, engineering, fasteners and service. Under their brand, IHF Fastener Systems, ITH have developed innovative fastener systems up to M80 (3 1/8"), which are specifically designed to match the technical demands of onshore and offshore wind turbine joints.
The “Maintenance-Free-Bolting” concept includes the technical coordination of ITH bolting tool systems with digital management software, specifically designed IHF fasteners, and advanced installation process know-how. The technical combination leads to repeatable, fast, and precise bolting procedures, which helps to reduce costly maintenance intervals on onshore and, especially, offshore wind turbines significantly.
Bolting Tool Method and Digital Management Software ITH bolt tensioning cylinders work according to the hydraulic, torsion- free, and friction-free bolt tensioning method. The method guarantees reproducible pre-tensioning forces within a close tolerance of ±2.0 percent.
For this method, ITH has developed a digital application management system, which offers customizable functions such as data-logging and step-by-step user guidance.
Depending on the demand of the customer, the bolting procedure and functions can be modified. All captured data such as applied pressure, applied preloads, angles of rotation of the nut run-down, bolt-ID, and more application data can be sent to a customer cloud.
Multi-Certified IHF Fastener Design and Benefits Bolted joints on steel constructions can be classified according to the HV- standard (HV stands for high-strength) according to DIN EN 14399 and DASt 021. Wind-turbine tower segments are mainly subjected to this standard, which determines that bolts are torqued and fastener sets consist of a bolt, a nut, and two washers. Torqueing is subjected to friction effects, which can affect the implementation of the applied preload forces FM
negatively.
IHF configuration with IHF Roundnuts: No washers required. IHF Roundnuts can be used with IHF head bolts in general up to M64, 2 1/2" or IHF studs bolts up to M80, 3 1/8".
Innovative IHF Fasteners – head bolts (in general up to M64, 2 1/2"), studs and round nuts (up to M80, 3 1/8") – are based on optimized design to meet the technical demands of wind turbine joints in terms of material, coatings, pre-load distribution, notch categories and dimensions.
Conventional HV-standard configuration (HV stands for “high strength”) compared to IHF fastener configuration and applied preloads for bolt size M36 (1 3/8").
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www.sosmagazine.biz February 2021
Optimized flange design options when using IHF Fasteners.
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