摘要 |
Apparatus for pyrolytically forming a metal compound coating on an upper face of a hot glass substrate 1 comprises conveyor means 2 for conveying the substrate 1 in a downstream direction 3. A coating chamber 6 opening downwardly onto the path 1 and means 7 for spraying coating precursor downwardly towards the substrate. The spraying means 7 is located to spray the coating precursor solution from a height above the substrate path 1 of at least 75 cm. Heating means are provided for supplying heat to the spraying zone 9. Means such as aspirator boxes 39 is provided for generating aspirating forces on atmospheric material within the passageway 13 to encourage such material to flow along the substrate path to the downstream end (27) of the passageway and to enter exhaust ducting leading such material away from the substrate path. In operation, the spraying zone 9 of the coating chamber 6 is heated to cause evaporation of part of the coating precursor material before it reaches the substrate 1 to charge the atmosphere in that zone with vaporized coating precursor material. The solution is sprayed with sufficient energy to ensure positive impact of residual sprayed coating precursor material against the substrate to initiate coating of the substrate face, and atmosphere laden with coating precursor material in the vapor phase is caused to flow in the downstream direction from the spraying zone 9 along and in contact with the coated substrate face for a contact time of at least 10 seconds, whereafter residual material of the precursor laden current is directed away from the substrate. |