Process for the manufacture of line and/or space for receiving or conducting hot gases
United States Patent Deutschmann et a].  
 14 1 Apr. 15, 1975 PROCESS FOR THE MANUFACTURE OF 2,387,971 10/1945 Aspin et al. 29/l56.4 WL x L E AND/ SPACE FOR RECEIVING 0 l(zlrelgory 123/191 M es e CONDUCTING HOT GASES 3,043,094 7/1962 Nichols.... [75] Inventors: Herbert Deutschmann, 4 11/1 2 Arne &#39;Friedrichshafen; Wolfgang Kurczek 3,069,209 l2/l962 Bauer 29/l56.4 WL X Nellingen; Karl-Heinz De Lazzer, Friedrichshafen, all of Germany Primary Examiner-C. W. Lanham Assistant Examiner-Victor A. Di Palma [73] Asslgnee: :g g Attorney, Agent, or Firm-Craig &amp; Antonelli PP NOJ 367,356 A process of manufacturing a construction for accom- Related Application Data modating a high temperature medium, particularly for [62] Division of Ser No 59 060 July 29 1970 Pat NO the accommodation and/or conduction of hot gases in 3 750 403 connection with exhaust gas lines and/or combustion spaces of internal combustion engines. The process [52] Us. CL 29/1560; WL; 29/446; 60/272; includes forming a heat resistant sheet metal liner with 23/191 A predetermined fold lines and placing the liner inside of 51 Int. Cl B23p 15/00 an unfinished relatively rigid Structure as to be in [58] Field 0fSearchm29/4465275,4479 1564 WL; engagement with inside walls of the structure. Subse- 123/187 R, 188 A, 188 AA, 191 R 191 A, quent thereto, the structure is casted and cooled such 191 L 191 M; 60/29 R 323 272 that the inside walls contract and force the bending of the liner along the fold lines such that insulating air [56] References Cited spaces are formed between the liner and the inside UNITED STATES PATENTS walls ad acent the fold lines. 1,926,499 9/1933 Ricardo 123/191 R 18 Claims, 2 Drawing Figures PROCESS FOR THE MANUFACTURE OF LINE AND/OR SPACE FOR RECEIVING OR CONDUCTING I&#39;IOT GASES This is a divisional application of copending application Ser. No. 59.060. filed July 29. I970. now U.S. Pat. No. 3.750.403.  
  The present invention relates to lines and/or spaces which are preferably provided with a cooling water jacket and serve for. the reception and/or guidance of hot gases. preferably. as exhaust gas lines and/or combustion spaces of internal combustion engines. particulary of Diesel engines with exhaust gas turbochargers.  
  With such types of lines and/or spaces. there occurs the problem that on the one hand. the outer surface temperature of the line or combustion space should be kept low and. on the other. the gas temperature should remain as high as possible. Particularly important is this problem in connection with the lines of Diesel engines having exhaust gas turbochargers because one aims in that case to make available to the turbocharger an energy level which is as large as possible.  
  With the known prior art constructions, the gasconducting lines and combustion spaces are provided with a cooling water jacket for keeping down the external temperature of the lines and of the combustion spaces. This cooling water jacket. however. at the same time strongly reduces the exhaust gas temperature and therewith the available energy for the exhaust gas turbocharger.  
  The present invention aims at providing gasconducting lines and/or combustion spaces which possess a relatively cool outer skin or surface as a result of a suitable insulation and simultaneously may serve for the conduction or the accommodation of a gas with a high heat energy.  
  The underlying problems are solved in accordance with the present invention in that the lines and/or spaces are provided with a heat insulation on the wall side in contact with the gas.  
  In a preferred embodiment according to the present invention. the wall of the line or of the combustion space. preferably madeof an aluminum casting. is lined on the inner side thereof with a separate wall whereby an air gap exists between the two walls. The wall of the line or of the combustion space may be lined advantageously with a sheet metal wall which is held at a predetermined distance from the wall by means of ridges formed in the casting of the wall or by beads or stiffening corrugations in the sheet metal. An air gap thus results very advantageously between the cast pipe or the wall of the gas space and the sheet metal member whereby the air serves as heat-insulating cushion. A heat transfer takes place only at the narrow contact places of the sheet metal member with the cast pipe or the cast wall at the ridges. The gas-conducting line or the combustion space may be cooled in a customary manner at the outer surfaces thereof by air or cooling water without reducing thereby substantially the exhaust gas temperature on the inside of the line or of the combustion space.  
  According to a further very advantageous feature of the present invention. an insulating sheet metal lining is cast-in into the line or into the combustion space. which lining lifts off from the wall during the cooling off of the line after the casting as a result of the shrinkage of the material and possibly assumes thereby a shape in the form of folds so that an intermediate space between sheet metal lining and the line wall or between sheet metal lining and combustion space wall is formed thereby. The manufacturing costs can be considerably reduced by casting-in the sheet metal lining. The position and size of the air gap can be predetermined beforehand. for example. by suitable design of the exhaust-gas collecting line or manifold or of the combustion space. However. it is also feasible within the scope of the present invention to utilize other linings as heat insulation.  
  Advantageously. a ceramic layer may also be applied as heat insulation on the side of the wall in contact with the gas. The application of the ceramic layer may take place by spraying-on. Also. an intermediate layer may be provided intermediate the wall and the ceramic layer.  
  A further advantage results during the assembly if the gas-conducting lines or combustion spaces of the present invention are constructed multi-partite whereby the separation can take place either in the axial or in the radial direction. It is appropriate. however. to construct the lines separated or subdivided into two half-shells. The half-shells may thus be lined in a simple manner with a heat insulation prior to assembly.  
  Accordingly. it is an object of the present invention to provide a hollow structure forming a line or space for receiving and/or conducting hot gases. which avoids by simple means the shortcomings and drawbacks encountered in the prior art.  
  Another object of the present invention resides in a structure forming a line or space for hot gases which permits the attainment of a relatively low external temperature of the structure while maintaining a high energy level of the gas present on the inside thereof.  
  A further object of the present invention resides in a line or space structure for Diesel engines with exhaust gas turbochargers in which a maximum possible energy level of the exhaust gases is available for the turbocharger without excessive temperatures at the outer surfaces of the structure.  
  Still a further object of the present invention resides in a line or space structure of the type described above which is relatively simple in construction. utilizes relatively few parts and can be manufactured and assembled without excessive expenditures.  
  These and further objects. features. and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows. for purposes of illustration only. two embodiments in accordance with the present invention. and wherein:  
  FIG. 1 is a transverse cross-sectional view through an exhaust-gas collecting line with an inserted sheet metal lining; and  
  FIG. 2 is a transverse cross-sectional view through a further embodiment of an exhaust gas-collecting line with a cast-in sheet metal lining.  
  Referring now to the drawing wherein like reference numerals are used throughout the two views to designate like parts. and more particularly to FIG. 1, this figure illustrates an advantageous type of construction of an exhaust-gas manifold or common line. for example. of a Diesel internal combustion engine provided with a turbocharger. The exhaust-gas collecting line generally designated by reference numeral 6 is lined in this embodiment at the inner wall 7 thereof with a sheet metal wall 8 which is held at a predetermined distance from the wall 7 by the ridges 9 provided in the casting of the wall 7 so that an air gap 10 results between the sheet metal wall 8 and the inner wall 7 of the exhaust-gas manifold or line 6. The cast ridges 9 are arranged at a predetermined spacing from one another along the inner wall 7. The air present in the air gap 10 assures a good heat insulation so that the hot gas conducted in the exhaust-gas collecting line 6 is cooled only slightly whereas the cooling water jacket 12 disposed between the inner wall 7 and the outer wall 11 of the exhaust-gas collecting line 6 assures a good cooling of the outer wall 11. Of course. it is also possible that the inner wall 7 of the manifold or common line 6 be constructed smooth and that beads or corrugations be provided in the sheet metal wall 8 which then keep the sheet metal wall 8 at a predetermined distance from the inner wall 7. For the sake of simplicity. such modification is not illustrated in the drawing.  
 FIG. 2 illustrates a further embodiment for the construction of the exhaust-gas collecting line or manifold generally designated by reference numeral 6. In this embodiment. a sheet metal liner 14 is cast-in into the exhaust-gas collecting line 6&#39; at the inner wall 13 thereof whereby the liner 14 during the cooling-off of the line. lifts off from the inner wall 13 as a result of the metal shrinkage and forms folds 15 so that an intermediate space 16 is formed between the sheet metal lining l4 and the inner wall 13. The air present in the intermediate space 16 again assures for a very good heat insulation of the hot gas with respect to the external temperature. The position and size of the intermediate spaces 16 can be predetermined beforehand. The inner wall 13 of the exhaust-gas collecting line 6 is provided with raised portions 17 which during the cooling-off phase after the casting. press the sheet metal lining l4 inwardly as a result of the shrinkage of the metal and thus favor a fold formation.  
  The multi-partite construction of the exhaust gas collecting line and/or of the combustion space which may be subdivided preferably into two half-shells is again not illustrated in the drawing for the sake of simplicity.  
  While we have shown and described only several embodiments in accordance with the present invention. it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to those skilled in the art. and we therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.  
 We claim:  
  1. A process of manufacturing a construction for handling high temperature mediums comprising:  
 forming a construction for accommodating .a high temperature medium by the steps of casting a rigid structure for said construction.  
 arranging a heat resistant sheet liner prior to said casting of said rigid structure so that said rigid structure and sheet liner are formed during said casting step into said construction with said sheet liner disposed inside said rigid structure. said sheet liner having a plurality of predetermined fold lines. and  
 cooling the thus formed construction of rigid structure and sheet liner to form a plurality of separate insulating air spaces between inside walls of said rigid structure and outer peripheral walls of said sheet liner. said plurality of insulating air spaces being formed by bending said sheet liner along said fold lines. thereby forming said plurality of insulating air spaces between alternate ones of said plurality of fold lines and said inside walls of said rigid structure.  
  2. The process of claim 1. wherein said rigid structure is a longitudinally extending duct structure. and wherein said fold lines are formed to extend longitudinally along the liner and duct structure.  
  3. The process of claim 2., wherein the inside walls of said duct structure are formed with inwardly projecting portions for aiding in the bending of said liner.  
  4. The process of claim 2. wherein the liner is formed of heat-resistant steel and the duct structure is formed of aluminum.  
  5. The process of claim 2, wherein said liner contacts said duct exclusively at said alternate fold lines forming the edges of adjacent air spaces.  
  6. The process according to claim 2, wherein said duct structure includes an inside duct and an outer casing having portions forming a cooling water space therebetween.  
  7. The process according to claim 1., wherein said construction is an exhaust gas manifold construction for an internal combustion engine. and wherein said rigid structure is an exhaust duct structure.  
  8. The process according to claim 7, wherein said liner is a sheet metal liner.  
  9. The process according to claim 8, wherein said fold lines are formed to extend longitudinally along the liner and duct structure.  
  10. The process according to claim 8. wherein the inside walls of said duet structure are formed with inwardly projecting portions for aiding in the bending of said liner.  
  11. The process according to claim 8, wherein the liner is formed of heat-resistant steel and the duct structure is formed of aluminum.  
  12. The process according to claim 8, wherein said liner contacts said duct exclusively at said alternate fold lines forming the edges of adjacent air spaces.  
  13. The process according to claim 9. wherein said liner contacts said duct exclusively at said alternate fold lines forming the edges of adjacent air spaces.  
  14. The process according to claim 8, wherein said duct structure includes an inside duct and an outer casing having portions forming a cooling water space therebetween.  
  15. The process according to claim 13, wherein said duct structure includes an inside duct and an outer easing having portions forming a cooling water space therebetween.  
  16. The process according to claim 15, wherein the inside walls of said duct structure are formed with inwardly projecting portions for aiding in the bending of said liner.  
  17. The process of claim 1, wherein said bending of said sheet liner along said fold lines is provided by contraction of said inside walls of said rigid structure during the step of cooling.  
 18. The process of claim 1, wherein said sheet liner contains said high temperature medium.  
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