The temperature is at a constant 700 degrees Celsius. Behind the heavy iron gate, 50 tonnes of aluminium is kept liquid. 24 hours a day, 365 days a year. The melting works only close down every three years, while the die cast plant, where the units are produced, only closes down twice every year.
Every day, some 30 to 35 tons of aluminium is melted in the furnace – corresponding to 4,500 tons every year. The metal is delivered in long bars, but the liquid metal also includes parts from production and old pumps. Our own pumps.
“We primarily receive the metal from Germany and the UK, and we only use recycled metal. Much of the metal has been used for aluminium rims and has driven on European motorways, or it has been used for beer and soft drink cans or as rims for bicycle wheels”, says Steen Heelund, Senior Technician.
The die cast plant was built in 1974 in North 1 and moved to its present address in North 3 in 1985. The 25th anniversary was celebrated with a completely new chimney, which makes use of a so-called electrostatic filter and efficiently purifies the smoke from one of Denmark’s last die cast plants. The filter is the only filter in the world that is used in a die cast plant.
“Back in the 1970s, we thought that we had to be able to do everything ourselves in terms of production. Today, we have developed our production process, and now casting of stator housing in aluminium is one of our core competences meaning that, following precision casting, the units can be used directly in production. We began doing that approx. 15 years ago. Previously, we had to make holes and finish most units”, Steen Heelund explains.
Fire without smoke
Every year, some 13.5 million units are cast by the 100 employees in the department. The almost 50 different units include stator housing, electronics parts, flanges and tops for terminal boxes – but stator housings remain the main product. All parts are used in all Grundfos departments all over the world.
“We are undergoing constant development – both with regard to products and in relation to reducing the environmental strain and energy consumption. We have managed to lower our gas consumption to about 60 m3 per ton, which is very positive – and among the lowest levels in the world”, Steen Heelund says.