Release time : 2015-06-15 13:09:00
Trelleborg Sealing Solutions, a worldwide leading developer, manufacturer and supplier of precision seals, develops a sealing configuration jointly
with Denmark-based AVN Energy A/S, a leading wind turbine hydraulic actuator manufacturer.
Previously, the companies successfully worked together on stall machines. This unique configuration is specially engineered to enhance lubrication and optimize friction characteristics, at the same time preventing any external leakage to meet the challenging requirements of continuous
The specified solution is a complex arrangement of seals ranging from O-Rings to specialized PTFE-based geometries. The actuator operates in
constant movement requiring dynamic criteria from the equipment's components. A customized seal system results in minimal turbine maintenance requirements due to prolonged life of the seal.
"The replacement of stall machine turbines by continuous pitch systems has put extreme demands on hydraulic actuators," said Tom Carew, Manager
of the Renewable Energy in the Trelleborg Sealing Solution Americas. "The would shift only once every ten minutes, but in continuous pitch wind turbine systems, the nacelle and angles of the blades constantly change in
small amounts once every rotation, on average 15 times per minute. This means that instead of producing six long strokes per hour, the turbine's
hydraulic actuator must now initiate nine-hundred short strokes in the same period, 24 hours a day, seven days a week, for a targeted 20-year period."
The seals within these hydraulic actuators are integral to its life is critical to the long-term effectiveness of the total system. Seals must operate at 3,625 psi/ 250 bars with constant pressure on the rod from
behind and differential side loads that control positioning. Wear has to be minimized, and dynamic movement that is continuous in short strokes needs to be facilitated. Temperature resistance is required down to -22XF/ -30XC as standard and to -40XF/ -40XC in the Arctic, with maximum
temperature capability of +140XF/+60XC.