July 8, 2021
DLM is a specialist in the design, manufacture, repair and calibration of load monitoring and other equipment for throughout the entire wind energy supply chain.
Load cells and monitoring equipment made by Dynamic Load Monitoring (UK) Ltd. (DLM), of Southampton, UK, is ubiquitous throughout the renewable energy supply chain. It is important to know the weight and centre of gravity of loads during the manufacture of towers, monopiles and transition pieces; and throughout transportation, erection, inspection and maintenance processes—on and offshore.
Wind continues to present unique challenges to everyone in the supply chain, principally because the location of instrumentation on a turbine array, for example, tends to be in the ‘splash zone’. Due to the remote locations and especially bad weather in places like the North Sea over the winter months, maintenance and repairs can be challenging. Therefore, the systems need to be suitably designed and robust enough to withstand the harsh conditions for long periods. DLM has gained experience in supplying products into this harsh environment with tried and tested methods for success.
It might not be known by everyone in wind energy that DLM’s marine-grade range of products includes shackles and grapnels for pre-lay grapnel run (PLGR) work, recovery and repair of cables. More familiar are its calibration and repair services in addition to its renowned saddleback monitors used in cable lay operations to measure line tension, running line monitors, load pins and load cells that capture data from wind turbines and other locations. Many of these solutions are custom designed and built to suit customers’ requirements. The company’s offering also includes wider technical engineering design support.
DLM works with various customers, depending on the project and the point of the supply chain (see insert). It has the capability to supply new and rented equipment from its conveniently-located Southampton base. The whole team is equipped to respond to enquiries and deliver state-of-the-art technologies to the point of use. However, Jamie Woodcock, business development manager; Adrian Farwell, marine sales manager; and Martin Halford, managing director, are perhaps the most familiar names to wind energy professionals. The latter sits on the board of the Lifting Equipment Engineers Association (LEEA).
DLM also offers a comprehensive welding and fabrication service through its sister company, Vulcan Offshore, at dovetails with its wind energy offering. It often proves to be a differentiator that the workshop is located near the Southampton port; when a vessel, barge, or workboat prepares for a project, clients typically have to modify and fit out the deck with winches, launch and recovery systems, cable engines, steps, ladders, and access platforms. As the vessels perform different functions depending on the job, equipment needs to be fabricated or welded to the deck of the ship. Vulcan welders are skilled in manual metal arc, metal inert gas, and tungsten inert gas welding. Many welders are also CSWIP 3.2 certified.
DLM is looking to further raise its profile in the wind energy sector. To that end, it has developed a data-logging device that provides load, angle, and acceleration data at high sample rates particularly for use in offshore renewables. The North Sea is an area of constant interest, but DLM has also highlighted the Americas as a likely hotbed of long-term activity, with Texas, Iowa, Oklahoma, Kansas, and California standout geographies.
Two recent case studies demonstrate the breadth of DLM’s wind energy services.
First, it manufactured two bespoke monitoring systems, installed by dive teams on subsea bend stiffeners at an offshore wind farm. The dynamic bend stiffener was a retrofit assembly attached to turbine cables that are subject to tidal loads that had been causing power cables to prematurely fail or reduce in efficiency.
The challenge was to monitor forces on the cables and the movement they experience over time, log the data over the course of a year, and make it periodically accessible. The system comprised three dual axis shear pin load cells, two accelerometers, and a programmable logic controller (PLC). The shear pin load cells were dual axis shear pins that measure forces across two planes in the positive and negative directions. The working load limit (WLL) of each plane was 50kN, in both the positive and negative direction.
Second, DLM provided a wireless weighing solution for a wind turbine manufacturing facility at nearby Fawley. The end user needed an accurate way of measuring the weight of their 80m-long turbine blades (the length of nine London buses back-to-back) at both the root and the tip upon completion of the painting process. The blades were actually made on the Isle of Wight before being transported to Fawley for painting and weighing.
DLM provided a 25t capacity telemetry tensile link and 20t capacity S-cell load cell, both selected from the company’s standard range because they are highly accurate and can be added into existing rigging equipment, easily and quickly. The data was read by the operator on two separate wireless handheld displays. The load monitoring equipment was rigged beneath the hooks of the site’s overhead lifting equipment.
While DLM provided a TL-2.0 (telemetry tensile link) in this instance, it has recently introduced a third generation of this load cell—a lightweight wireless tension measuring unit that combines a high level of performance with a robust design for harsh environments. It is made from aerospace grade aluminium and offers a range up to 800m (over 2,600 ft.) and a huge battery life of 700 hours. The TL-3.0 can be paired with unlimited amount of displays to one load cell or 12 load cells to one handheld display.