Heat exchanger for internal combustion engine exhaust, with noise suppressor

A noise-suppressing heat exchanger, comprising:

• wall means, including two opposite header end walls and a perimetrical sidewall, defining an enclosed gas flow space;
• an outer shell completely, spacedly enclosing said wall means of said gas flow space so as to define a liquid jacket substantially completely surrounding said gas flow space;
• said wall means including means mechanically supporting said wall means relative to said outer shell;
• a plurality of liquid flow pipes extending generally parallel to one another, each having opposite ends opening through respective of said opposite end walls of said wall means, into said liquid jacket;
• means defining a liquid inlet through said outer shell into said liquid jacket and a liquid outlet from said liquid jacket through said outer shell, the liquid inlet and liquid outlet being so arranged that a relatively cool liquid which is to be heated may be introduced into the liquid jacket via said liquid inlet, traverse said gas flow space within said tubes while being warmed by indirect heat exchange with a relatively hot gas flowing in said gas flow space, re-enter said liquid jacket and flow out said liquid outlet as a relatively warmed liquid;
• means defining a gas inlet through said outer shell, said liquid jacket and said wall means into said gas flow space and a gas outlet from said gas flow space through said liquid jacket and said outer shell, the gas inlet and gas outlet being so arranged that a relatively hot gas which is to be cooled may be introduced into said gas flow space via said gas inlet, traverse said gas flow space externally of said tubes while being cooled by indirect heat exchange with said relatively cool liquid and flow out said gas outlet as a relatively cooled gas;
• a plurality of partition walls disposed in said gas flow space at a respective plurality of locations intermediate said two opposite end walls, with said liquid flow pipes penetrating said partition walls;
• these partition walls, with said wall means, dividing said gas flow space into a plurality of serially adjoining compartments;
• at least two of said partition walls being so spatially disposed relative to said wall means and to one another as to provide that said compartments of said gas flow space are of at least three different sizes;
• and
• means defining at least one small hole through each partition wall, these small holes being so sized and located as to ensure that said gas in traversing said gas flow space must travel externally crosswise as well as externally lengthwise of said liquid flow pipes, and undergo multi-stage expansion,
• whereby noise emanating from said gas is muffled by a combination of enclosure by said liquid in said liquid jacket, and attenuation by flowing successively through said at least three different-sized compartments.