Wind turbine gearboxes operate in some of the harshest environments, from salty offshore platforms to dust-laden plains, and must run continuously for years with limited access to maintenance. At the heart of these systems lie high-speed rotating components, including the gearbox output shaft, the generator interface, and, in some direct-drive designs, high-speed rotor hubs.
This blog post examines polymer labyrinth seals as a solution for sealing the gearbox in powerful wind turbines.
Wind Turbine Gearboxes
The gearbox is one of the most critical components in a wind turbine. It converts the relatively slow rotation of the blades into the high-speed rotational motion required by the generator. If the gearbox fails, the entire turbine is offline, leading invariably to lost power production and costly repairs. The fact that turbines are often installed in remote or offshore locations means that repair logistics can be difficult, expensive, and dangerous.
The Challenge of Gearbox Contamination in Wind Turbines
Wind turbine gearboxes are highly susceptible to contamination and loss of lubricant through seal leaks. Sources of contamination are many, including dust, moisture, salt spray, and environmental particulate matter, all of which depend on the location of the turbine. Such contamination leads to several problematic issues, including accelerated bearing and gear wear, significant efficiency losses, and lubrication degradation.
Traditional sealing solutions, such as lip seals and metal labyrinth seals, often fail short in long-term wind turbine use.
Polymer Labyrinth Seals for Wind Turbine Gearboxes
Labyrinth seals address sealing challenges with a non-contact design that forms a tortuous path to block ingress and retain lubrication without generating friction, heat, or wear. Most contaminants and lubrication will lose their kinetic energy before they are able to traverse the entire labyrinth. This design makes it extremely difficult for dust, moisture, or lubricant to move in or out. The fact that it is non-contact means that it does not add any friction and eliminates the heat generated and energy loss associated with it.
When PTFE, PEEK, and Torlon labyrinth seals are used in place of metal, the final result is a lightweight, corrosion-resistant seal that can stand up to harsh conditions while keeping friction and wear to a minimum. In addition, these polymers support more design freedom when it comes to geometries as well as excellent tribological performance even under the harsh environments associated with wind turbine gearboxes.
These non-contact seals prevent contamination and lubrication by making it almost impossible to pass through the labyrinth without losing energy, extend the service of the wind turbines, and support less frequent (and often dangerous) maintenance.
Performance Benefits in Wind Turbine Gearboxes
Polymer labyrinth seals are ideal solutions for wind turbine gearboxes. They are non-contact solutions, which eliminate the friction and wear experienced by traditional lip seals. This also means that the gearboxes will not suffer a loss of efficiency related to seal wear, as well as the accelerated wear associated with the ingress of problematic contamination and the problematic loss of lubrication. Because they are polymers and have excellent chemical compatibility, corrosion issues are eliminated. Polymer labyrinth seals are also resistant to ozone aging, depending on the type of material selected.
The effectiveness and long life of these polymeric seals extend the service life of wind turbine gearboxes. This also reduces the costly downtime and logistics associated with repair and regular maintenance.
Conclusion
Polymer labyrinth seals are a critical reliability upgrade for wind turbine gearboxes, with benefits that include extended service life, reduced downtime, and lower maintenance costs. The combination of a non-contact seal with engineering polymers leads to an excellent solution for the numerous sources of contamination that could otherwise destroy a wind turbine gearbox.
If you are working on a new wind turbine or seeking to upgrade existing wind turbines, it is hard to go wrong with high-quality polymer labyrinth seals. And that happens to be one of our specialities at Advanced EMC.
