D-shaped tube for header

Abstract

Disclosed is a water cooled exhaust assembly for use in association with an internal combustion engine in a marine environment. Inner and outer nested tubes are affixed to a mounting flange to form, in conjunction with an access port in the mounting flange, a cooling water flow channel to provide cooling of exhaust gases from the engine. The inner tube is formed with a flattened portion to produce a reduction in exhaust gas turbulence in the flow channel with a consequent increase in heat transfer capability.

1 . A water cooled exhaust assembly, comprising: 
 an outer tube portion;    an inner tube portion having a generally free end thereof;    and a mounting flange for supporting said assembly relative to an associated internal combustion engine;    at least one cooling water entrance port formed in said mounting flange; and    at least one cooling water exit port formed in said outer tube portion;    wherein said inner and outer tube portions are configured for said inner tube portion to pass exhaust gases from an associated internal combustion engine while a space is formed between said inner and outer tube portions for defining a cooling water channeling system in conjunction with said entrance and exit ports; and    wherein said inner and outer tube portions have predetermined shaped correspondence between the walls thereof, for reducing turbulence of the flow characteristics of cooling water passing therethrough, for improved heat transfer characteristics.    
   
   
       2 . A water cooled exhaust assembly as in  claim 1 , wherein said inner tube portion defines a relatively flattened area thereof, to provide said predetermined shaped correspondence.  
   
   
       3 . A water cooled exhaust assembly as in  claim 2 , wherein said relatively flattened area of said inner tube portion is generally near an end thereof relatively adjacent to said mounting flange.  
   
   
       4 . A water cooled exhaust assembly as in  claim 3 , wherein said inner tube portion defines an angled cut portion therethrough adjacent said relatively flattened area thereof, to collectively form a relatively “D” shaped opening therein.  
   
   
       5 . A water cooled exhaust assembly as in  claim 1 , further including at least a second water cooling exit port formed in said outer tube portion.  
   
   
       6 . A water cooled exhaust assembly as in  claim 1 , wherein said outer and inner tube portions and said mounting flange are all welded together.  
   
   
       7 . A water cooled exhaust assembly as in  claim 1 , wherein said mounting flange has a plurality of bolt holes formed therein, for securing said mounting flange to an associated internal combustion engine.  
   
   
       8 . A water cooled exhaust assembly as in  claim 1 , wherein said at least one cooling water entrance port formed in said mounting flange has a generally “C” shaped configuration.  
   
   
       9 . A water cooled exhaust system for internal combustion engines, comprising: 
 an assembly of nested exhaust and cooling jacket pipes; and    an exhaust manifold attachment flange, for simplified coupling of both exhaust emissions and cooling water to said assembly;    wherein said nested pipes have a predetermined shape between the walls thereof, for improved heat transfer characteristics by reducing turbulence of the flow characteristics of cooling water passing therethrough, for more efficient heat transfer.    
   
   
       10 . A water cooled exhaust system as in  claim 9 , wherein: 
 said nested pipes include respective inner and outer tube portions;    said inner tube portion defines a relatively flattened area thereof generally near an end thereof relatively adjacent to said attachment flange; and    wherein said inner tube portion defines an angled cut portion therethrough adjacent said relatively flattened area thereof, to collectively form a relatively “D” shaped opening therein.    
   
   
       11 . A water cooled exhaust system as in  claim 9 , wherein said attachment flange further includes at least one cooling water entrance port formed in said mounting flange, and having a generally “C” shaped configuration.  
   
   
       12 . A water cooled exhaust system as in  claim 9 , wherein: 
 said attachment flange includes at least one cooling water entrance port formed therein;    said nested pipes include respective inner and outer tube portions;    said inner tube portion has an angled cut therethrough adjacent an end thereof relatively adjacent said attachment flange, and having a relatively flattened sidewall portion thereof, collectively forming a relatively “D” shaped opening; and    said relatively flattened portion of said inner tube portion is operative together with said outer tube portion so as to form a portion of a water flow channel from said cooling water entrance port of said attachment flange, and extending from where an end portion of said inner tube portion is joined with said attachment flange, and through a defined space formed between said nested inner and outer tube portions, such that said relatively flattened portion cooperating with the inner surface of said outer tube portion contributes to a significant reduction in turbulence in the cooling water flowing through the defined space between said inner and outer tube portions, with a corresponding improved opportunity for heat transfer from hot exhaust gases in said inner tube portion to the cooling water.    
   
   
       13 . A water cooled exhaust system as in  claim 12 , wherein: 
 said outer tube portion is generally round in diameter and has a cut through portion thereof and terminating in an end portion thereof generally corresponding in cut angle to a similarly shaped portion of said inner tube portion, with an exit end portion of said outer tube portion defining two access portions formed, respectively, as a cut out portion of said exit portion of said outer tube portion, and as a through hole formed in the exit portion of said outer tube portion on a side thereof generally opposite that of said cut out portion thereof; and    wherein said cut out portion of said outer tube portion cooperates with said inner tube portion to form an exit outlet for cooling water flowing through the space formed between said respective inner and outer tube portions while said an additional opening is defined in said outer tube portion to provide a supplemental exit port for cooling water flow.    
   
   
       14 . A methodology for improved heat transfer from exhaust gases of an internal combustion engine to cooling water in a water cooled exhaust system of the type having an assembly of nested pipes, such assembly having an inlet end, an outlet end, and respective relatively inner and outer pipes thereof, and configured to pass exhaust gases of the internal combustion engine through the relatively inner pipe thereof, and to permit cooling water to flow between an outer surface of such inner pipe and an inner surface of the relatively outer pipe thereof, the improvement methodology comprising providing predetermined shaped correspondence between the walls of the nested pipes to reduce the turbulence of the cooling water flow between the nested inner and outer pipes, which in turn improves heat transfer to the cooling water.  
   
   
       15 . A methodology as in  claim 14 , wherein such providing the predetermined shaped correspondence comprises defining a relatively flattened area in the inner pipe.  
   
   
       16 . A methodology as in  claim 15 , wherein such defining a relatively flattened area in the inner pipe includes defining the relatively flattened area generally near an end of the inner pipe relatively adjacent to such assembly inlet end.  
   
   
       17 . A methodology as in  claim 14 , wherein such providing the predetermined shaped correspondence comprises defining a relatively flattened area in the inner pipe, with an angled cut portion through such inner pipe and adjacent the relatively flattened area thereof, so as to collectively form a relatively “D” shaped opening in such inner pipe.