Stormproof

The most important function is performed by a ring seal at the top of the pile: It encloses the interior part of the linking piece that supports the screw connection. In modern installations, this flange seal with the abbreviation MP-TP (monopile transition piece) can reach a diameter of eight to ten meters. Freudenberg Sealing Technologies has also offered this seal in a double version in recent years. The main advantage of the double-row design is the resulting redundancy, as Freudenberg expert Manuel Hille explains: “If minor damage occurs at one of the two seals during the transport or installation, the function is still ensured. In addition, this makes it possible to optimally combine different designs and materials with each other.” However, the specific design is almost exclusively customer-specific in order to make optimum use of the available assembly space. Freudenberg also offers an already established standard product upon request.

In a conventional design, a gap remains between the lower end of the connecting piece and the pile. One or two ring seals interspersed with air chambers designed as elastic breakwaters ensure that no seawater can enter. On the other hand, if the gap is filled with cement, a ring seal can keep the cement in the desired position during the curing and later protect it against damage from saltwater. Maintenance platforms, which are often positioned above the water surface inside the monopile, can additionally be protected against ingress of gases with a specially designed seal. These kinds of gases may form due to biological seawater processes in the pile.

Designed for long life