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Publication numberUS3908372 A
Publication typeGrant
Publication dateSep 30, 1975
Filing dateAug 15, 1974
Priority dateAug 15, 1974
Publication numberUS 3908372 A, US 3908372A, US-A-3908372, US3908372 A, US3908372A
InventorsRobert N Balluff, Charles P Fowler
Original AssigneeTenneco Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Heat shield for exhaust conduits
US 3908372 A
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Description  (OCR text may contain errors)

United States Patent [1 1 Fowler et al.

[ 1 Sept. 30, 1975 1 1 HEAT SHIELD FOR EXHAUST CONDUITS [75] Inventors: Charles P. Fowler, Jackson; Robert N. Balluff, Rives Junction, both of Mich.

[73] Assignee: Tenneco lnc., Racine, Wis.

[22] Filed: Aug. 15, 1974 [21] Appl. No.: 497,672

[52] US. Cl. 60/320; 23/288 F; 138/114 [51] Int. C1. ..F01N 3/14; F16L 11/00 [58] Field of Search 60/298, 320, 272, 286, 60/299; 23/288 F; 138/131, 134, 38, 114;

[56] References Cited UNITED STATES PATENTS Cullom 138/114 Heath 60/320 Kern 60/320 Primary E.\'aminerDouglas Hart Attorney, Agent, or FirmHarness, Dickey & Pierce [57] ABSTRACT A flexible heat shield for the outside of a conduit of an internal combustion engine exhaust system comprises numerous metal coils, preferably parts of a helical strip, which longitudinally overlap on one edge and have standoff flanges engaging the conduit on the other edge, the coils being perforated in accordance with a program that locates the holes on the bottom side of the conduit.

1 Claim, 3 Drawing Figures U.S. Patent Sept. 30,1 975 3,908,372

HEAT SHIELD FOR EXHAUST CONDUITS BRIEF SUMMARY OF THE INVENTION It is the purpose of this invention to provide a heat shield for an exhaust system conduit that is imperforate on top, perforate on the bottom, and flexible.

The invention accomplishes this by means of a series of separate, relatively movable metal coils, preferably interconnected in a helical strip, that overlap each other and have flanges to space them from the conduit. The coils are preferably made from strip metal that is intermittently perforated in a numerically controlled punch press operation so that when the coil is slipped on a pipe, the holes will be on the bottom.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side elevation of a motor vehicle internal combustion engine exhaust system having a conduit heat shield embodying the invention;

FIG. 2 is a cross section along the line 2-2 of FIG. 1; and

FIG. 3 is a cross section broken away, along the line 3-3 of FIG. 2.

DESCRIPTION OF THE INVENTION An internal combustion engine 1, of the type used on automobiles and trucks such as indicated by phantom line V, has an exhaust manifold 3 that discharges exhaust gas into an exhaust pipe 5 that is part of an exhaust system 7. The pipe 5 carries gas to a gas treating unit 9 such as an acoustic silencer (muffler) or an emission control device, e.g., a catalytic converter. A tailpipe 11 carries treated gas away from the unit 9 to discharge it through an open end 13 into the atmosphere.

The invention is of special use when the device 9 is a catalytic converter. In accordance with the invention a metal shield 15, preferably low carbon sheet steel strip, is disposed around at least those portions of the tailpipe that are likely to be dangerous because of their high temperature. The shield comprises numerous individual annular coils 17 that are preferably the separate but interconnected turns of a helically coiled strip of steel. Tailpipes normally contain one or more bends in them, as illustrated at 19 and by the gap 21, and the shield of this invention may be installed after the pipe is bent by slipping it over an end of the pipe and moving it longitudinally to the desired location.

The coils 17 each have a short transverse flange 2 along one edge that engages the outer surface of the conduit and serves to space the main longitudinally extending portion of each coil from the conduit. The other edge 27 of each coil rests on top of and overlaps the flanged edge of the adjacent coil, the length of the overlap being long enough to prevent actual separation of the coils on the outside of any bend in the conduit. Due to metal thickness, the portions 25 have a slight taper and this provides some elastic pressure between the overlapped portions of adjacent coils.

The space between each coil and the conduit comprises an air gap 29. In the form shown the gaps of each individual coil actually merge into each other to form one continuous, helical gap extending the full length of the shield and preferably open to atmosphere at each end. The bottom sides or halves of the gaps preferably open to atmosphere by way of several apertures 31 formed in the coil portion 25. The top sides or halves of the coils are preferably imperforate, however. This arrangement provides maximum shielding of the top of the hot conduit while permitting the flow of cooling air through the gaps and out of the apertures 31 in the bottom of the coils. Thus, the floor of an automobile, for example, is shielded from the top of the conduit and grass, weeds, etc., are shielded from actual contact with the bottom of the conduit.

As indicated above, the apertures 31 are prepunched in the strip from which the coils are formed in precontrolled patterns that cause them to be located on the bottom when the shield is slipped on the pipe. A numerical control program can be used to control the hole formation on a punch press; and it can be rather easily varied to accommodate variations in pipe shape, bends, etc., as compared with costs of retooling to change hole location. If desired the shield may be welded, bolted or otherwise secured to the conduit to positively prevent it from creeping out of position. Certain types of exhaust system hangers (not shown) may provide tight clamps that extend around the shield to prevent creeping.

Modifications may be made without departing from the spirit and scope of the invention.

We claim:

1. In an internal combustion engine exhaust system including a gas treating device and a horizontally extending exhaust gas flow conduit having an outer surface and connected in series to the device, a heat shield mounted on the conduit and comprising a series of Iongitudinally overlapping annular coils that are longitudinally adjustable relative to each other whereby they may be fitted over bends in the conduit while substantially maintaining longitudinal contact with adjacent coils, each of said coils having a transverse flange along one edge that contacts the outer surface of the conduit to space the coil from said outer surface, the other edge of the coil slidably fitting on the outside of the flanged edge of the adjacent coil, the space between the coil and the outer surface of the conduit comprising an air gap, at least the top half of said coils being imperforate, the bottom half of said coils containing apertures to provide for the flow of air through the coil, said coils comprising interconnected turns of a helically coiled

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3740930 *Apr 28, 1971Jun 26, 1973J CullomCorrugated balloon flue
US3863445 *Aug 4, 1972Feb 4, 1975Tenneco IncHeat shields for exhaust system
US3864909 *Jul 26, 1972Feb 11, 1975Boysen Friedrich KgThermal reactor with relatively movable internal pipe sections
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4083694 *Mar 19, 1976Apr 11, 1978Nissan Motor Company, LimitedHeat insulating device for an engine exhaust system
US4501302 *Oct 14, 1983Feb 26, 1985Apx Group, Inc.For carrying heated vehicular exhausts
US4590652 *Nov 14, 1984May 27, 1986Apx Group Inc.For use with an engine exhaust system
US4619292 *Jan 30, 1985Oct 28, 1986Apx Group, Inc.Air gap pipe
US4656713 *Oct 24, 1985Apr 14, 1987Ap Industries, Inc.Method for forming an air gap pipe
US4955193 *Jul 17, 1989Sep 11, 1990Custom Chrome, Inc.Adjustable shield for motorcycle exhaust pipe
US5233832 *May 14, 1992Aug 10, 1993Soundwich, Inc.Damped heat shield
US5347810 *Aug 4, 1993Sep 20, 1994Soundwich, Inc.Damped heat shield
US5590524 *Jun 13, 1994Jan 7, 1997Soundwich, Inc.For an exhaust system of an internal combustion engine
US6298935 *Dec 17, 1999Oct 9, 2001Scambia Industrial Developments AgExhaust system for a motor vehicle and a motor vehicle with the exhaust system
US6397589Aug 31, 2000Jun 4, 2002Custom Marine, Inc.Exhaust pipes and assemblies
US6536548 *Jul 20, 2001Mar 25, 2003Scambia Industrial Developments AgExhaust system for a motor vehicle and motor vehicle with an exhaust system
US7007720 *Apr 4, 2000Mar 7, 2006Lacks Industries, Inc.Exhaust tip
US7451541Feb 4, 2005Nov 18, 2008Pratt & Whitney Canada Corp.Method of heat shielding an inner tube
US7585559Mar 23, 2004Sep 8, 2009Intellectual Property Holdings, LlcFoam barrier heat shield
US7686131 *Dec 16, 2008Mar 30, 2010Gm Global Technology Operations, Inc.Vehicle exhaust tip assembly
US7799840Sep 4, 2007Sep 21, 2010Intellectual Property Holdings, Llcrecycled polyvinyl butyral blends is used to expand to a foamed state; including polyvinyl acetate and/or ethylene-vinyl acetate copolymer, vinyl acetate-vinyl versatate copolymer; body panel of an automobile
EP0276648A1 *Jan 2, 1988Aug 3, 1988TeZet Service AGExhaust manifolds for internal-combustion engines
Classifications
U.S. Classification60/320, 422/173, 180/309, 180/89.2, 138/114
International ClassificationF01N13/14
Cooperative ClassificationF01N2470/24, F01N2470/12, F01N13/14
European ClassificationF01N13/14