Sealing Solutions for Wind Turbines

Wind turbines are an incredibly popular source of renewable energy. This is not only because wind is an abundant source of energy, but it also provides electricity without burning fuel, which pollutes the air. Wind turbines require seals to help with efficiency and production. To find out about sealing solutions for wind turbines, continue reading our expert guide below.

Wind power explained

The utilisation of wind power has emerged as the most developed alternative energy source, particularly in the developing economies, and it is steadily growing at an unprecedented pace. Wind energy, which is harnessed through the use of a wind turbine, involves the conversion of kinetic energy from the wind into electrical energy. The blades of the wind turbine are subject to the wind’s force, causing them to rotate. Each blade can rotate independently to absorb varying levels of energy from the wind. The blade is connected to a motor, which is safeguarded by a large O-ring to prevent contamination from water or dirt.

This rotational motion is transmitted to a shaft that is directed to a gearbox. The gearbox converts this low-speed rotational motion into high-speed motion, which is subsequently used to generate electricity through a generator. The electrical energy produced is then conveyed to a transformer, which raises the voltage to a level compatible with the national grid’s voltage. This process necessitates the connection of electrical cables, which are insulated with high-quality materials, such as silicone, to prevent the loss of electricity through dissipation and to protect the cables from pollution.

Each onshore wind turbine has the potential to generate electricity sufficient to power an average of 1500EU homes, whereas an offshore wind turbine can supply energy to approximately 3312EU homes. In the UK, wind power contributes to 26.1% of the total electricity generated.

Wind turbine seals

Wind power plays a vital role in the transition to renewable and sustainable energy sources. According to the International Energy Agency (IEA), in 2019, solar and wind energy accounted for 86% of renewable energy, proving its importance in the constant pursuit of cleaner energy sources.

As the power output of wind stations rapidly rises, the demands on wind turbine components are also on the increase. The length of a wind turbine blade is crucial to its efficiency. Research showed that the larger the blade, the higher the power production capacity. In fact, in the last decade, wind turbine blades have grown from 60 metres to over 100m. Some power facilities actually have wind turbine blades with a diameter of 180m, generating an incredible amount of force.

However, the increase in the length of a turbine blade has led to a growth in weight, reducing the optimal efficiency of the rotor. Other challenges a wind turbine will face include the impact of major temperature changes and other weather fluctuations, salt air, ultraviolet light, other media effects (oil and grease) and ozone. All of these factors can impact a wind turbine’s operation and efficiency, and these extremes require the use of advanced technologies.

The main requirements for sealing solutions for wind turbines are low friction and optimal wear behaviour that will maximise operating efficiency and expand its lifespan for many more years. A seal life of 20 years is often the target for sealing requirements. Wind turbine seals often have to withstand use in high-pressure applications, so must have a resistance to high pressure.

Depending on the area of deployment, there is also a requirement for high and low-temperature resistance.

Sealing solutions for wind turbines include shafts, bearings and gearboxes.

Benefits & importance of wind power seals

The construction of wind turbine seals relies on an array of polymer materials, including polytetrafluoroethylene (PTFE), thermoplastic polyurethane (TPU), and ultra-high molecular weight polyethene (UHMW). The utilisation of polymer materials in wind turbine seals offers numerous advantages, including reduced build costs, decreased weight, and minimising maintenance expenses.

These materials exhibit exceptional resilience to wear and extrusion, along with ultra-low friction levels, making them ideal for use under abrasive conditions – a capability not always afforded by elastomeric seals. As a result, these materials guarantee an extended seal life, creating a more controlled and bearing-friendly environment.

Effective engineering of wind turbine seals results in extended periods between component failures, decreased manufacturing costs, and reduced power consumption stemming from excessive friction.

What type of seals are used for wind power seals?

At the hub of a wind turbine, where the blade’s pitch, the junction must be absolutely weather tight, but must also allow rotation. A range of materials are well suited to the job, but a moulded O-ring works well due to its good performance in part to a rust-proof tension spring which pulls the seal against a rim. Profile rings for large seal diameters have vulcanised joints, giving them an advantage over glued rings.

Other components that require sealing solutions on wind turbines include the main shaft and slewing bearings.

For slewing bearings, nitrile rubber (NBR) is used as a sealing material for grease and ozone resistance, low-compression set, and low-temperature capability. The material was developed especially for long-term reliability and superior resistance to extreme environmental conditions. This reduces maintenance time and costs, increasing the lifespan of the seal and wind turbine.

Wind turbine seal polymers at TRP

At TRP Polymer, we are able to manufacture large seals over 3m in diameter for use as pitch seals and turbine-bearing seals. We can also manufacture rotary seals and anti-vibration mounts.

Also, we can produce seals for accumulators, such as piston seals and static seals. We can manufacture seals used with pitch cylinders, such as:

• Piston Seals
• Rod seals
• Wiper seals
• Static seals

And, we’re experts in seals used in electrical connections:

• Low permeability seals, designed to withstand -45C to 260C and provide the optimum mean time between scheduled maintenance.
• Conductive rubber sleeves.
• Insulating rubber sleeves, diaphragms, O-Rings and custom seals. 

If you’d like more information on the type of material that we manufacture at TRP Polymer, including those for use as wind power seals, do not hesitate to contact us today at 01432 268899, or email us at sales@trp.co.uk. 

Speak to one of our specialists today to discover our complete range of custom moulded rubber seals, and types of FFKM.