Heat exchangers not being parts of machines, namely, brazed plate, gasketed plate, shell and plate, welded plate, spiral, and shell and tube heat exchangers; coils as parts of distilling, heating or cooling installations, namely, coils for heating systems, heat recovery applications, and process applications; air cooling apparatus, namely, aftercoolers for cooling compressed air and gases; Heat sinks for use in heating, cooling and ventilating apparatus; heating systems composed primarily of ...