Apparatus and installations for heating, steam generating, refrigerating, drying, ventilating, humidifying, steam and curing, namely heat sinks for use in heating, cooling and ventilating apparatus, dryers for the removal of water vapor from compressed air and gases, ventilating exhaust fans, electric vaporizers, humidifiers, steam generators, and parts and fittings therefor; thermal, gas, phytosanitary and sterile treatment installations for natural and synthetic fibres, yarns and threads, c...