APPLIED TECHNOLOGY BEARINGS
BEARING DESIGNS SUPPORT DEVELOPMENT OF A FLOATING LIQUEFIED NATURAL GAS FACILITY
52 vertical elastomeric bearings and 156 horizontal bearings have been manufactured by Trelleborg for use on the 13 modules onboard the world’s first floating liquefied natural gas (FLNG) project – Shell’s Prelude FLNG. In addition, 40 turret bogey bearings have been provided to enable natural movements of the turret. Commenting on the application, Byoung-Gark Park, topside structural engineer for Samsung Heavy Industries, said: “Many of Prelude’s topside modules weigh as much as a single typical offshore platform. In fact, along with its contents, Prelude is expected to weigh a total of 600,000 tons. So, optimum quality and performance of the bearings used to secure each module is vital.” Meeting the demands,
Trelleborg’s elastomeric bearings are steel plate laminated and installed between the hull of the facility and its modules. These accommodate axial, shear and rotational movement to keep the modules safe from
impact, damage and deformation. Similarly, they prevent the concentration of excessive strains and stresses around the mounting points of the modules and the hull caused by adverse sea and weather conditions. “We design and manufacture all of our elastomeric bearings specifically for their application, to ensure
that they always perform exactly as required. This approach was especially important for the Prelude topside, to guarantee that the record-breaking weight could easily be supported over its life. We are very proud to have been selected to supply such a landmark project,” commented JP Chia, engineering manager for Trelleborg’s engineered products operation.
Trelleborg
www.trelleborg.com
DRUMMING UP INTEREST IN WASHING MACHINE DESIGN
To help accommodate greater laundry capacities, as demanded by consumers, washing machine manufacturers are moving towards larger drum diameters – with many modern machines capable of washing up to 9kg of dry textiles. This, however, results in higher forces being applied to the drum shaft support bearings. In Europe front loading machines are popular, and these present an even greater challenge. As the weight of the loaded drum is applied to one side, this subjects the bearings to high loading – which is then exacerbated by an imbalanced rotating mass, placing great stress on the bearing. To meet the demands,
NSK engineers began work on improving bearing materials. The primary goal was to enhance the chemical composition of an existing NSK special steel so as to prevent the instigation and propagation of cracks and dents. Particular attention was also paid to rolling contact fatigue, which refers to subsurface defects in the micro-structure that can lead to surface flaking. Here, a particularly pure steel alloy was identified to help alleviate this issue. The development work resulted in BNEQARTET
bearings, which are said to offer double the service life of standard bearings and are suitable for use even in adverse operating conditions. For instance,
6 NOVEMBER 2016 | DESIGN SOLUTIONS
Having received an order for 250 buses from Go Transit in Toronto, engineers at Alexander Dennis (ADL) needed to work out how to keep passengers comfortable in a city where temperatures can vary from -25˚C in winter to 35˚C in summer. ADL designed the uprated heating
and air conditioning system specified, but the compressors and alternators needed a shaft and intermediate bearings to transfer power from the engine. With the engine supplier quoting 18 months to supply an appropriate unit, ADL turned to SKF. Taking into account the loads,
a significant improvement was achieved in tests that sought to generate flaking on the surface of the bearing raceways when operating in polluted environments. Here, NSK’s BNEQARTET bearings were found to be more resistant to contamination. In addition, during tests the
bearings were found to be capable of operating at high temperatures – at 150˚C, approximately 1.5 times longer service life could be achieved, the company explains. Resilience or insensitivity to hydrogen is another attribute of the material used for NSK’s BNEQARTET
bearings. This is important because hydrogen molecules can penetrate deep into the material and cause embrittlement, even at room temperature. The bearings are available as deep-groove ball versions. Although suited to drum support applications in washing machines, these can be used where a design engineer wishes to avoid rolling contact fatigue and/or surface damage through contamination.
NSK
www.nskeurope.com
speeds, operating conditions and life expectancy, the team applied its proprietary engineering tools, including the Bearing Beacon 3D modelling system, to create a suitable system design and select appropriate components. The full design was then modelled using Creo CAD software. For quiet, efficient operation and a
long service life, SKF based the design on its SKF Explorer deep groove ball bearings. These feature a design of advanced, high purity steel, with a homogenised structure and superior finish on all contact faces. This is combined with an optimised design of bearing cage and balls. As a result, the bearings reduce friction by around 50%, leading to lower levels of heat and noise and a longer life. In addition, each bearing is protected from the ingress of contamination by SKF’s V-ring seals. Happy with the design, ADL asked SKF to assemble and supply complete bearing units for its Canadian contract, including pulleys and other secondary components. Making use of its UK workshop, SKF was able to assemble all the units for the original order, beating a tight delivery deadline by two weeks.
SKF
www.skf.com
HELPING TO ENSURE PASSENGER COMFORT ON TORONTO’S BUSES
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 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52
