Wind Turbine Seal Challenge
Because of the wide variation in where wind turbines are located, seals are expected to operate under temperatures between -40°F in the Artic to 140°F as a maximum standard operating temperature. Wind turbines are exposed to UV and ozone, vibration, and high stresses. Wind turbine parts are expected to last for twenty years a considerable challenge for such rigorous conditions, but a challenge that is being met. One area where these issues are being addressed is in the design and retrofitting of seals.
Check out additional articles on advanced polymer component solutions in the wind energy industry:
- Polymer Seals for Wind Energy Applications 101
- Polymer Seals: Key to Wind Turbine Bearing Life Extension
- What is Polytetrafluoroethylene (PTFE), a flash of genius or a lucky accident for mankind?
Wind Turbine Seals
In a wind turbine, you will find seals in the main bearing, main gear, pitch cylinder, lock cylinder, main and yaw brakes, and the hydraulic accumulator. Seals are one of the most critical components in a wind turbine for extending the life of a wind turbine, maximizing efficiency, maximizing reliability, and minimizing maintenance costs.
When seals fail, it is typically because they have simply worn out as they have reached the limit of their expected life. The problem lies in things that can reduce seal life once it has been installed. Heat aging, as a seal is exposed to high temperatures for extended times, can reduce the effective mechanical properties of the seal. Extended exposure to ozone and UV rays can weaken the seal and result in catastrophic cracks. Exposure to corrosive and abrasive media can also weaken a seal and reduce its useful life.
Benefits of Polymer Seals
The proper choice of a polymer seals can mitigate or eliminate many of the life-reducing issues. The main choices for polymer seals are PTFE (aka, Teflon) and TPU (thermoplastic polyurethane), and UHMW PE (ultra-high molecular weight polyethylene). There is a laundry list of reasons why these materials are popular for seals:
- Extremely low friction
- Good tear strength
- UV resistant
- Require less rigorous surface requirements for the mating surface
- Ability to perform in abrasive conditions
- Resistance to extrusion
- Reduction in bearing failure due to the ingress of contaminants
- Reduction in maintenance requirements
- Extension in the service life of turbines
These seals can be manufactured by extrusion or machined to custom dimensions, both processes offering excellent precision. In addition, there are various flavors of each of these polymers, including composite seals that offer even greater and more specialized mechanical properties.
Polymer seals have been found to outperform their elastomeric counterparts in various sealing applications for wind turbines. Whether you are designing a wind turbine from the ground up, or making design modifications in the field, dont ignore the potential of polymers for extending the life of your wind turbines.
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