Descriptions for F28 and notes/indexes are displayed on this screen.


Note(s)
    In this class, the following expressions are used with the meanings indicated:
      "heat exchange" means the heating or cooling of a fluid or fluent solid by direct or indirect contact with a heated or cooled fluid or fluent solid;"heat transfer" means the heating or cooling of a fluid or fluent solid by direct contact with a heated or cooled surface or body.
    Apparatus using heat exchange or heat transfer (as defined in Note (1) above) for specific purposes is classified either in subclass F28B or in the appropriate subclasses of, for example, classes F22, F24, F25, F26, or F27; if no such other subclass is appropriate, such apparatus is classified in subclass F28C or F28D.