Fluid technology expertise at high altitudes

Whether the Danish North Sea, the Chinese desert or the American grasslands: In wind farms all over the world, a large amount of dosing and metrological expertise from Gevelsberg and Neuenrade has often been involved along the way.

The rotor blades of modern wind turbines, which are up to 90 meters long, are usually manufactured using two half moulds. Glass fibre mats and other materials such as balsa wood elements are laid out in these shells. The whole piece is then soaked with a special resin under vacuum, heated and baked to a flexible but stable rotor blade half section. The two halves are then placed together and affixed. For stabilisation, the manufacturers mount what are known as shear webs in the hollow sheet.

A considerable amount of technology from VSE and Beinlich is in this entire process. Both in the vacuum injection systems used to produce the rotor halves, as well as in connecting the individual elements with adhesive resins. Pumps in the ZPD series are used here, among others. These are designed for high discharge capacity and high working pressure and can easily handle the high flow rates required.

The two blade halves are connected with adhesive resins (red markings). The shear webs are also glued.

„Overall, a whole range of our products can be used in rotor blade production.“

What are known as barrel pumps are similarly used, and these are ideal for the type of media being processed. The adhesive resins are usually highly viscous and abrasive, which means that the fluid is not only very viscous, but also has a certain solids content.

This places special demands on the mechanical components in the pumps and metering stations of the dosing systems.

In this sector, the two sister companies VSE and Beinlich now have over 20 years of experience that is extremely valuable to manufacturers of rotor blade production plants. It is not just in the composite construction of the rotor blade where the technical expertise of the two companies is in demand; it is also important in the screw mounting of the blade onto the rotor dosing and adhesion technology: The blades are secured to the hub with several hundred screws or bolts, and for these fastening bolts, the manufacturers glue metal inserts into the rotor blade in advance. Two-component or multi-component adhesives are used here, and the high precision dosing of these chemicals is a further area of specialisation at VSE and Beinlich.

The VS series from VSE and the ZPD series from Beinlich Pumpen

The fully assembled rotor is generally then painted or covered with another finish. Even with this application, the fluid technology from Neuenrade often ensures precise and even distribution. "Overall, a whole range of our products can be used in rotor blade production", says Axel Vedder. "From the large RS helical screw sensors to classic VS models to the smaller VHM series, and ultimately the whole range".

The market for wind turbines is currently growing at tremendous speed, not least because of the fact that China is vigorously upgrading its environment and establishing wind farms at a great pace. "The plants for rotor blade production are then simply built right next to these farms," says the Head of Technology at VSE. This type of plant can produce rotor blades for an estimated seven to eight years, before it is replaced. Several hundred of these and similar plants have been providing VSE and Beinlich with dosing and measuring equipment around the world in recent decades. There is no end in sight just yet, not least because wind farms continue to be on the rise in times of booming "Green Energy" both on land and offshore. In addition to this, rotor blades are wearing parts that are replaced after a few years. "Definitely one of our growth markets."