Mobile pre-heating cell consists of a self-supporting frame structure fitted with an outer metal sheet coating and an inner coating made of heat-insulating plates; the free space between the coatings is filled with thermal insulation. The cell is equipped with an openable front wall with an inner grid. The opposite rear wall has a hole with a holder of a hot-air heater near its upper edge. Near the lower edge of the hole there is a horizontally positioned membrane, on which there are mixing channels for air circulation. The sensor of the hot-air heater is in the heating space of the cell. On the floor of the cell there is a roller track.<IMAGE>
