Apparatus for lighting, heating steam generating, cooking, refrigerating, drying, ventilating, water supply and sanitary purposes; air deodorising apparatus; air filtering installations; air purifying apparatus and machines; air reheaters; desalination installations; distillation columns; dust removing installations for industrial purposes; electric dust removing apparatus; evaporators; factory chimney flues; fire bars; furnaces; gas boilers; heat accumulators; incinerators; installations for processing nuclear fuel and nuclear moderating material; ionisation apparatus for the treatment of air; kilns; nuclear reactors; pressure water tanks; refining towers for distillation; steam generating installations; tanks for storage; water intake apparatus; water supply installations; heat exchangers; heat recovery steam generators; reactors