Furnaces; Coils as parts of distilling, heating or cooling installations; Electric furnaces; Electric rotisseries; Electrical induction heating apparatus for heating metal workpieces; Furnaces for melting metals; Furnaces for recovering scrap metals; Heating elements; Heating installations; Holding furnaces and melting furnaces for industrial use; Industrial furnaces; Melting furnaces; Quenching apparatus for heat treatment; Smelting machines