By Michael Jermann, Assistant Editor
Many designers think it is impossible for machine products made of a co-polyester elastomer to be heavyweights. The safe stopping of maintenance boats servicing wind turbines in the North Sea proves the opposite.
Wind turbine installations are controversial on land, but at sea they are credited with great potential as a system for producing energy. They are imposing towers as seen close up, but not exactly beautiful. It stands to reason that their daily visitors will not be tourists, but service technicians. Wals Diving & Marine Service arrives as service technicians. They have the responsibility of repairing cables and carrying out maintenance work on the wind turbines. For a long time, docking was a real adventure for Wals-Service teams.
Tubus Bumpers, made from co-polyester elastomer, are designed to withstand 1 million load cycles.
In contrast to docking on land, docking at sea requires a work platform to ensure safe transfer of men and equipment because of constant movement, swell of waves and limited space. The appearance suggests that a hydraulic maneuver basket is needed. In reality, and for safety’s sake, the construction is a rigid object, which is fixed to the boat.
Tubus bumpers can also absorb lower energies of 10 in.-lb with progressively higher energies up to 10,000 ft-lb.
This means that the captain must slow down the entire weight of the maintenance boat, plus 20% more, when docking. The additional weight is due to an estimated impact speed of approximately 1.6 ft/s and the power of the waves. This is why the Wals Company struggled for a long time with continuous damage to their light, polyester transport boats. Furthermore, there was always a potential for injury to employees. A new and easy way to integrate a docking solution was needed from ACE Controls while avoiding reconstruction of boats if at all possible because of economic reasons.
This provided the impetus to look at suitable ACE Tubus Bumpers instead of industrial shock absorbers. The Tubus Bumper application allowed a 70% cost saving, without compromising safety.
The bumper’s resistance to seawater and its material—which can withstand surrounding temperatures of –40°F to 194°F—made it ideal for use in ships. Having considered all the benchmark data, such as the aforementioned mass and impact speed, the company decided to install four Tubus Bumpers, Type TS84-43.
The bumpers can withstand 4,000 lb-in. per stroke under continual usage. When the Tubus is only used for emergencies this value increases to 5,600 lb-in. per stroke.
ACE Controls Inc.
www.acecontrols.com
Filed Under: Design World articles, Green engineering, Materials • advanced
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