| 摘要 |
To compact granular moulding materials, in particular foundry moulding materials, the invention proposes a method in which the moulding composition is compacted by means of a compressed-air impact on the upper side of a loose moulding composition. The intensity of the compressed-air impact necessary for compaction is achieved by setting the volume of the mould space and the volume of the pressure space in mutual dependence, by enriching the pressure space with compressed air to a maximum of 10 bar and completely equalising the pressure building up due to this compressed air and taking effect above the moulding composition with the pressure decreasing simultaneously in the pressure space, this being done in a time of 0.1 s at the maximum, by maintaining the resulting pressure for at least 0.12 s and by reducing this pressure to normal pressure in a time greater than 0.2 s. This method makes it possible to convert compressed-air pressures of from 1 bar to 10 bar into compressed-air impacts and to apply the quantity of air moved during this process in massive form to the surface of the moulding material.
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