| Maintenance & rehabilitation
How did Gilkes overcome these challenges with innovative or unique solutions? Gilkes engineers carried out reverse engineering, including 3D scanning techniques, CAD modelling and machining using a five axis machine. To initiate the process of creating a 3D model, Gilkes performed a visual inspection of the two available runners to identify the one in better condition. Given the debris, corrosion, and damage to multiple blades, a decision was made to scan 180° of the best runner, with a focused scan on two blades with minimal visible damage. This strategic approach ensured accuracy in replicating the existing blade geometry. The large size of the runner combined with the
relatively small space between the blades presented challenges for the scanning process. To overcome these, Gilkes employed various techniques, including the use of matt white paint to enhance laser projection, adjusting shutter speeds, and employing finer scanner movements. These measures were crucial in overcoming the challenges posed by the physical constraints of the scanning process. The output of the scanning process was a mesh generated from the collected data points. Gilkes then utilized a combination of scan post-processing software and CAD software to create a 3D model from the surfaces developed from the mesh. The cleaning process involved removing small spikes, narrow gaps, and noise created during the scan, resulting in a base for blade profile sketches. Given the thin blade thickness in some areas (as low as 1mm), Gilkes implemented a meticulous process to create a smooth and accurate blade surface. This involved producing a flow path of the meridional plane, capturing crown and hub profiles, and importing a scanned mesh of a single blade into the 3D model. The blade profile sketches derived from this process were used in a surface lofting approach, allowing precise control over contours and curvature. The final step included patterning the single blade 18 times and combining it with the crown and hub profiles to complete the 3D model.
How did these technologies contribute to the restoration process and the overall performance of the turbine? The above techniques were used to create replacement parts, allowing the machine to be reassembled to a working state. The use of modern engineering techniques
throughout this project enabled Gilkes to bring the machine back to life, whilst extending the lifespan of the equipment and reducing future maintenance requirements. The commissioning process, completed in June 2022, marked a milestone as the refurbished turbine now delivers approximately 12% more power. This enhanced output is directed towards powering the visitor center and hotel, with surplus electricity exported to the grid. The decision to scan the runner played a crucial role in achieving these outcomes. By accurately replicating the proven runner geometry, Gilkes eliminated the need to develop a new runner design from scratch. This not only expedited the restoration process but also ensured that modern materials and parts were seamlessly integrated, contributing to the turbine’s
long-term smooth operation. Importantly, the utilization of these modern technologies allowed Gilkes to address pre-existing issues that had contributed to the turbine’s catastrophic failure, effectively designing out those challenges. Despite encountering various challenges
throughout the project, including discovering initial damage, creating a new CAD model, and overcoming access and installation difficulties, Gilkes successfully delivered the project within a customer-acceptable timeframe. The refurbishment stands as a testament to the enduring link between New Lanark and the River Clyde, ensuring that the mills at New Lanark continue to harness the power of the river for generations to come. The modern engineering techniques not only resurrected a historic turbine but also positioned it as a sustainable and efficient source of power for the foreseeable future.
How did Gilkes ensure that the restoration maintained the historical authenticity of the 1931 turbine while incorporating modern materials and technologies? By reusing the same turbine case and as much of the other remaining external components as possible, to maintain the overall heritage appearance. Rather than replace all parts as per the original design, the decision was made to modernise aspects with up-to-date materials and components. This approach offered improvements in performance and durability while maintaining the look and operation of the 90-year-old turbine.
Were there any specific considerations or challenges in blending historical preservation with operational efficiency? Yes, following initial discussions that the project was to maintain as much of the original equipment as possible, allowance was made for certain components to be upgraded where this would enhance the operation of the machine. Hard-wearing, corrosion-resistant materials were not
prevalent when the machine was initially designed in 1931. Seizing the opportunity to enhance longevity and reduce maintenance, Gilkes opted to replace some worn components with modern alternatives. Original components, such as guide vane supports and operating ring bearings, were prone to corrosion and wear. For instance, carbon steel guide vane supports rusted heavily, leading to the seizing of guide vane bushes. The operating ring bearings, separated by steel rollers, faced challenges related to limited access for relubrication, resulting in frequent seizing. Additionally, the original shaft bearings, constructed with white metal shells, posed concerns due to potential damage and extended replacement lead times. The solution was to make much more use of stainless steel. This included guide vanes, shafts and operating ring parts. This would prevent the parts from corroding and seizing, however it did not remove the internal greasing issue. For this problem, the rollers were removed altogether and replaced with a stainless steel filler segment. This was then separated by a modern metal-backed polymer liner. The liner has excellent low friction and maintenance free properties which eradicated the need for grease within
Above from top to bottom: Scanned runner Turbine runner scanned mesh Runner blade profile sketches Full 3D CAD of runner
www.waterpowermagazine.com | February 2024 | 13
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37
