Over the decades to come, we will see a continuous increase in the proportion of wind power in the global energy mix. The goal is for wind farms to supply electricity at a price lower than that of fossil energy. As a result, the manufacturers of rotor blades and of dispensing and mixing systems for adhesives will have a number of challenges to overcome in the future.
The key considerations when manufacturing rotor blades for wind turbines are to shorten the production time while reducing production costs. At the same time, wind farm operators require a warranty on the blades lasting for more than 20 years. In order to fulfil all of these requirements, the different disciplines involved need to pool their expertise and work together efficiently. The dispensing, mixing and application of adhesives in particular play an important role.
In the case of rotor blades that are more than 100 meters in length, up to 1200 kilo grams of adhesive are needed to bond the two halves of the blades together. Both the length of the blades and the amount of adhesive required are likely to increase in the future. The open time of the adhesive is generally around 45 minutes at 25 °C. Regardless of the blade size, the bonding process must be completed within this time. The adhesive is measured using high resolution volume counter units with a closed loop regulation system for each of the adhesive components. Sensors can also be integrated to monitor the application temperature within the required tolerances.
To meet the requirements imposed by longer rotor blades and increasing amounts of adhesives, Dopag has developed very large dispensing and mixing machines with 400 litre buffer tanks for each component. They have mobile refilling stations to reduce the amount of space needed for the dispensing system, which is an important consideration in the production facilities of many businesses.
