In this station, the still liquid impregnating agent, which is in the porosity or leakage path of the workpiece, is converted into the solid state.
This happens almost everywhere by associating the batch with hot water (90 degrees Celsius). Another possibility is heating with hot air, but this is a very expensive matter because the heat transfer from air to the workpiece is quite unfavorable.
This is not the case when using hot water. On the one hand the water is an excellent heat store and on the other hand the heat transfer is very good and fast.