were installed above furnaces in the same way as forge hearth extraction sys- tems. Very high air transport capacities are required due to the large separating distance from the furnace platform. In order to increase the air speed at the end of the hood, flow nozzles were installed in the funnel. Since these hoods have to be swung to the side for charging and casting, a complicated swivelling system is also necessary. In order to reduce the high separating distance during melting, raising and lowering systems can also be fitted. One could say that this system can be optimised, but for the same result, the costs are significantly higher than with other extraction systems.