Added Value For Wind Energy

2023 Author: Hannah Pearcy | [email protected]. Last modified: 2023-05-24 11:12

The main shaft seals, which keep external influences away from the main bearing and the transmission components, primarily serve to protect modern wind turbines. They also prevent lubricants from escaping. SKF engineers have developed a special generation of radial shaft seals that meet the specific requirements of wind power generation: the HRS series

The development

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While commercially available shaft seals are sufficient for comparatively small, double-bearing main shafts, significantly higher loads, deformations and speeds occur in modern, ever-larger systems with high performance and sometimes simply mounted rotors.

In order to meet the increasing demands, the SKF engineers first had to determine the conditions resulting from the different drive train concepts: e.g. Seal diameters from 350 mm to 3600 mm, standing and rotating housings, different accessibility of the seal carrier, various lubricating greases, possible locations including local environmental conditions, etc. During development, the team used internally developed software to influence the influence of temperature, bearing deformation, pressure and Simulate manufacturing tolerances and complex dynamic processes such as the ability of the sealing lip to follow eccentricity with different temperatures and rotation speeds. The resulting ideas were quickly implemented in prototypes and tested on our own large seal test bench.

From theory to practice

The company's team of experts worked closely with turbine manufacturers and operators to determine the real behavior of materials, lubricants and sealing profiles. For example, they used the first prototype seals in turbines, in which the sealing systems used to date caused problems due to excessive leakage, excessive wear or costly replacement of seals. The knowledge gained with regard to the installation behavior and the performance of the prototypes was used to optimize the test models.

lubricant

SKF lubricates Constance courtesan "Imperia"

It turned out, for example, that even small differences in the drive train and the bearings or their lubrication can lead to very different behavior. Although the sealing element as such has no influence on these parameters, the variety of load cases had to be included in the further development in order to enable the safety and service life of the sealing elements in a wide range of applications.

The final sealing profile was installed in wind turbines in Germany, Denmark, France, South Korea and China, among others. These applications were used for validation because they represent a meaningful cross-section of the application parameters and could be inspected regularly, which in turn allowed documentation of the performance. After a period of between 1.5 and 2.5 years, it was clear that the seal could reduce the leakage - many systems even ran leak-free.

The sealing material

The G-Ecopur sealing material used is a polyurethane developed and produced by SKF itself. It is a thermoplastic elastomer: As a seal, it behaves similarly to a rubber material, but has a higher mechanical stability. In operation, the HRS seal is characterized by the excellent ability of the sealing lip to follow, with which ± 3 mm shaft runout can be permanently compensated. The recommended operating temperatures for G-Ecopur are between –30 ° C and 110 ° C; the seals can be exposed to significantly lower temperatures down to –70 ° C without destruction. The seal has been successfully tested in field applications up to a speed of 2.5 m / s on the sealing surface. (br)