Over deze norm
||Vaste Minerale Brandstoffen
A test piece, in the form of a pencil, prepared from powdered coal is heated at a constant rate in a steel retort positioned in a furnace, the temperature monitoring system having been previously calibrated using two reference metals of known melting points. The change in level of a piton resting upon the test piece is observed continuously, and record is produced which is characteristic of the swelling properties of the coal.
||Hard coal - Determination of the swelling properties using a dilatometer