Force fit of the steel towers to the foundations at the Piiparinmäki mega wind farm secured by liquid liner MM1018

Tower-to-tower superiority: the steel towers are secured to the foundations of the Piiparinmäki mega wind farm with MM1018 liquid liner plate

In Finland, the country’s largest wind farm is currently being built in the municipalities of Pyhäntä and Kajaani. The project comprises a total of 41 powerful turbines with a total output of 211 MW. In order to ensure a permanent and highly precise frictional connection between the 155 m high steel towers and the foundations, the gap compensation on the imposing ring flange connections in the foundations was carried out using the liquid lining sheet MM1018 P from DIAMANT Polymer GmbH. MM1018 P is a highly filled, pasty metal polymer for the full-surface and force-fit compensation or filling of inaccuracies and unevenness between metal elements, which is increasingly being used worldwide in the construction of impressive wind turbines.

Efficiently securing the basis for renewable energy generation

Wind turbines play an important role in the realization of the energy transition. The foundation of a wind turbine represents the transition from the tower to the ground. It secures a wind turbine from sinking in or falling over. It also absorbs the lateral forces acting on the tower. Just like any other large building or structure, a stable foundation is essential. It serves as an anchorage and gives the turbine a firm and stable base.

The ever larger steel towers to which the turbines are attached are exposed to enormous forces. This poses technical challenges for the larger flange connections with which the towers of the wind turbines are connected to their foundations by bolts. To prevent these bolts from loosening – a problem that is often associated with considerable repair costs and downtime – the connecting flanges must be flat and tight to the millimeter so that no excessive stresses can build up. Only with exact flatness can flanges and their components meet the high demands of a long service life for wind turbines.

Lack of fitting accuracy of the flanges can impair bolts

Where safety, stability and efficiency are of the utmost importance, the liquid liner sheet MM 1018 comes into its own. Welding the flanges into the foundation often results in warping and splitting. Inaccurate flange fits and fatigue can affect the bolts and thus the stability of the turbine tower, necessitating repairs and leading to longer, costly downtimes for the operator. Maintenance over the lifetime of a wind turbine can account for up to a quarter of all costs.

“We are proud to support the development of the wind energy industry. By securing the tolerances, we are helping to ensure the integrity of these large structures and thus the production of green electricity for many years to come,” says Carsten Kunde, Managing Director of DIAMANT Polymer GmbH, with satisfaction.

High-precision tolerance compensation at lightning speed

Until now, the surfaces of the flanges in the foundations of the steel towers of wind turbines were often corrected manually at great expense in order to achieve an approximately flat surface. With MM1018P, unevenness, gaps and out-of-tolerance joints in steel components can be evened out quickly, easily and efficiently. The liquid lining sheet creates a force-fit and form-fit connection between steel components in a short time.

Gap compensation carried out by experienced DIAMANT specialists

In order to achieve the best possible frictional connection between the foundations and turbine tower at the Piiparinmäki mega wind farm in Finland, the Finnish wind farm operator took advantage of the service offered by DIAMANT Polymer GmbH to have a team of experienced specialists carry out the gap compensation on the imposing ring flange connections of the tower foundations.

To do this, the foundations were first carefully cleaned. In addition, a durable, resistant DIAMANT screw protector was used to prevent the threads from sticking to MM1018 later on. The liquid MM1018 P lining sheet was then precisely applied in paste form. The highly filled metal polymer enables high-precision, full-surface and force-fit compensation of gaps, inaccuracies and unevenness between metal elements. Finally, the excess material was properly removed.

MM1018 P is characterized by very high compressive strength, fast curing and permanent corrosion and weather resistance. The great advantage of MM1018 compared to conventional steel lining sheets is that MM1018 always fits in every situation and does not need to be mechanically processed or adjusted. This saves time and costs during installation and enables smooth building acceptance.