US 1996622 A
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April v2, 1935. F. M.-LAMB ERT 1,995,622?
SHEET METAL RADIATOR Filed Feb. 4, 1951 3 Sheets-Sheet 1 v 1-vw 7'a/? Zita/2017M Zamerfi whwess BY W I n rramv'zv April 1935- F. M. LAMBERT 1,996,622
SHEET METAL RADIATOR Filed Feb. 4, 1931 3 Sheets-She et 2 Earle/15M Zamenf w nwsss Br @MM HYTTOHNQ'Y April 2,1935. A BE T 1,996,622
SHEET METAL RADIATOR Filed Feb. 4, 1951 3 Sheets-Sheet 3 Patented Apr. 2,' 1935 PATENT orrica.
SHEET METAL RADIATOR Francis M. Lambert, Narberth, Pa., assignor to Heintz Manufacturing of Pennsylvania apparatus and particularly to sheet metal radiators, and an object of the invention is to provide an improved radiator of this character which has 5 its primary heating surface, or what is sometimes known as the radiator body or tube, made of a steel alloy of high surface stability, so as to resist rust and other corrosion and thus have a more permanent character and longer useful life, and which at the same time has a high degree of thermal efflciency as compared with sheet metal radiators heretofore employed.
Such steel alloys of high surface stability are commonly called stainless steel and for convenience will be so designated herein, although it is to be understood that the term as here used does not refer to the quality of stainlessness, strictly speaking, since discoloration is not of importance in connection with the present invention, but refers to the characteristic of having corrosive-resistant surfaces.
While the use of stainless steel for making the primary heating surfaces of sheet .metal rad1- ators is of great advantage because of its corrosive-resistant property, there is, on the other hand, a difficulty in the way of its use owing to the fact that it has a lower thermal conductivity than the ordinary steel usually employed for the purpose, and hence its use is apparently less desirable from the standpoint of thermal efllciency.
I have discovered that this problem can be overcome by making the primary surface of the radiator of stainless steel" which is relatively thin, and suitably securing to the primary surface a plurality of diathermic fins of a different metal having a higher thermal conductivity than the stainless steel".
By making the walls of stainlessstee relatively thin, the rate of heat transfer transversely therethrough is increased so as to maintain an efficient and satisfactory heat output not withstanding the relatively low thermal conductivity of the stainless steel. To this end the thickness of the stainless steel used, is reduced, preferably as much as practicable consistent with the range of pressures, or differences in pressures against its inner and outer surfaces, which the primary surface of the radiator must be able to withstand according to the character of heating system with which it is to be employed. Such relatively thin walls can not be safely used where the primary surface is of ordinary sheet steel or like corrosive metal, since they become weakened under the corrosive action of the heating medium,
and hence when such corrosive metals are em- Company, a corporation 19in. Serial No. 513.251
ployed the walls must be thicker than would otherwise be necessary, in order to aiford a margin of safety, but even then the continued corrosive action weakens them as time goes on and thus limits the useful life of the radiator. However, with 'myinvention the use of relatively thin walls is rendered possible owing to the corrosiveresistant 'quality of the stainless stee and in spite of the reduced thickness of the walls the radiator has both a safe and permanent characl0 ter. The use of relatively thin walls also permits a saving of metal.
By suitably securing the diathermic fins to the primary surface, the relatively thin walls of the latter are reinforced and at the same time the 15 heat transferred through such walls is given off rapidly to the air. The latter function would not be satisfactorily 'performedif the flns'were made of stainless steel since the relatively low conductivity of that metal would prevent the 2 heat from traveling rapidly in the planes of the respective fins and hence the fins would not operate efficiently to transfer the heat to the air. But by making the fins of a diflerent metal having a higher thermal conductivity than stainless steel I .overcome this difficulty and secure the efficient emission to the air of the heat transferred through the stainless steel" walls of the primary heating surface.
The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, and the advantages possessed by it, reference should be had to the following descriptive matter and the accompanying drawings, in which I have de-v scribed and have illustrated certain embodiments of my invention. p
In the drawings- Fig. 1 is a side elevation, partly broken away and partly-in section, of one form of sheet metal radiator embodying my invention.
Fig. 2 is a top plan view thereof, partly broken away and partly in section. 4
Fig. 3 is an end elevation thereof, partly. broken away and partly in section.
Fig. 4 is a transverse, section on the line 6-4 of Figure 2, parts being broken away and the cap being removed.
Fig. 5 is a transverse section, partly broken away, showing the two companion sections of the radiator body spaced apart, the. sections being equipped with fins and ready to be assembled.
Fig. 6 is a fragmentary side elevation, partly 55 broken away, of another form'of sheet metal radiator embodying my invention. 1
. away, on the line 8-8 of Figure 6. Fig. 9 is an .end view,showing this form of the invention in its open position, ready for final assembly. v l
Fig. 10 is a detailed sectional view, showing "the use of rivet projection welding for securing of giving off rapidly'to the air the .heat transferred through such thin fst'ainlesssteel walls.
' companion sections homogeneous joints produced the Inthe embodiment of my invention shown in Figs. 1 to 5,'inclu sive, the primary'heating-surface or body of my-improved sheet metal radiator the. range of pressures, or difference in pressures against its inner and outer surfaces, which the primary heating surface must be able to withstandaccording to the heating system with which 'the radiator is to be employed; Under ordinary conditions I-flnd that l8 or 20 gauge sheet stainless steel is suitable for the purpose of the present invention.
Each section is substantially pan-shaped and is provided along its upper and lower edges with outstanding flanges 3 adapted to abut against the corresponding flanges of the other section when the sections are later assembled. The panshaped form of the-sections is employed where-it is desired to have the primary surface in the form of a flattened tube vertically elongated in crosssection, and has the. advantage of providingbroad, flat, vertical faces on each side of the primary surface. I
The sections are. formed at both ends with semi-cylindrical portions or members I extending vertically entirely thereacross and provided along theinfree; or outer side edges with outstanding flanges 5. The corresponding portions 4 are adapted to match with their flanges 5 in abutting relation whenthe sections I and 4 are assembled,- whereby to' provide a tubular inlet and a'tubular outlet at the opposite ends of the primary surface or radiator body.
After the two sections have been thus formed and before they are united, each section has a seriesof vertically, disposed fins 8 secured to and projecting perpendicularly from the outer face I of its side wall. These fins are made of any suitable sheet .gmetal having a higher conductivity than stainless steel, as for instance, ordinary .steel or, aluminum. The fins on each section are spaced apart at suitable longitudinal. intervals, andextend' across the broad, flat outer face of the section in extended thermal contact there with. In this embodiment of the invention, the fins are shown as U-shaped in cross-section with The fins are rigidly and permanently secured even contact therewith, so as to serve the dual function of reinforcing the broad, flat side walls of thin stainless steel toincrease their rigidity and ability to withstand pressure differences, and
In order to'secure the fins eflectively-tothe by electric welding are employed. When there is no marked difference in the coeflicients of expension of the stainless steel forming the primary surface or radiator body and of the differseam welding or projection welding .is employed according as found most suitable On the, other hand; when there is a marked difference in such coemcients of-expansion, rivet projection welding is employed, in which instance a rivet I is inserted through an opening 8' in the fin and welded to the outer face of the stailess' steel body section, as shown in Fig. 10. The opening 8 is of slightly larger diameter than the rivet 1 in order. to permlt suflicient play to, take up the diiierence in expansion between the body. sections and the fins. The rivet is preferably. of the same material as entmetal forming the fins, spot welding, roller the radiator bodyto avoid producing in the area of the weldadifierent alloy which might not be corrosive-resistant, and then too a different metal wereused=for the rivet the weldmight be porous or non-homogeneous and permit the heat;- ing medium to work out into the rivet and corrode it to such anextent that it might come loose or the heating medium eat through.
All of these methods of welding require access to and operation from both the inner and outer faces of the radiator body, particularly where the latter is ,made of relatively thin sheet metal,
since it is necessary that a support be provided on the inner face to prevent deformation of the thin wall under pressure'exerted by the outer elecmatching relation and the abutting flanges 3 and 5 thereof electrically welded together as by roller seam welding or any othersuitable welding process, to provide homogeneous fluid-tight joints. Interiorly screw-threaded bushings 9 are inserted in the open ends of the tubular inlet and outlet in the opposite ends of the-radiator and welded in place, to complete the radiator. The bushings are made of the same material 'as the radiator body so as to avoid the possibility of setting up electrolytic action under the influence of the heating medium, as would be likely to occur if posed to theheating medium.
- when thus assembled, the radiator is complete and ready for installation, except that where 'flns "the radiator embodied'diiferentmetals, both ex-' of regular steel are employed, it is preferably dipped or sprayed or otherwise given anexterior coating-of paint'orother suitable material. In
installing the radiator the pipeconnections IL for the supply and return for the heating medium, such as hot water or.steam, are fitted, respectively, to one. of the bushings 9 of the inlet and one of the bushings 9 of the outlet. In such in stance a closure plug H is applied to one of the remaining bushings 9 and a cap provided with an air valve ll may be secured to the other. The
radiator may, of course, be installed not only as a single unit but in other suitable ways. For instance, two or moreunits may be installed in superimposed relation, with connections between the lower bushings of the upper unit and the upper bushings of the lower unit. at
In the embodiment of the invention shown in Figs. 6 to 9, inclusive, the companion sections I'- and 2 are formed from a single sheet of relatively thin stainless steel bent upon itself or folded so that the sections are joined along one edge, preferably the upper edge as indicated at N, and are initially spread apart from such edge, as shown in Fig. 9. In this position access is afiorded to the inner faces of the sections, thus permitting operation from both the inner and outer faces thereof to secure the series of fins 6 to the outer faces by means of electric welding as above described. In this embodiment the semicylindrical portions or members 4 extend longitudinally of the sectionsfor. a suitable distance from the ends thereof, and are adapted to match, upon the assembling of the sections, to-provide a tubular inletand a tubular outlet which open outwardly in a horizontal direction at the opposite ends of -the radiator. The interiorly screw-threaded bushings 9 which are secured within the open ends of the inlet and the outlet to receive the pipes Ill, may be, and preferably are, welded to one of each pair-of corresponding semi-cylindrical portions 4 while the companion sections are in their open position. Upon the subsequent assembling or closing together of the companion sections, the outstanding flanges 3 along their lower edges and outstanding flanges 3 cent the Joined edge I thereof, and co-act in the assembled position to provide a nipple within which an interiorly screw-threaded bushing I is such radiators but may be employed in making sheet metal radiators of other materials. It is also to be understood that the form of the companion sections of the radiator body and also of the inlet and outlet thereof may be varied as desired in different instances; that fins of angular form in cross-section or any other suitable shape may be employed and that various other changes may be made without departing from the spirit and scope of the invention as defined in the ap-.
Havingthus described my invention, I claimand desire to protect by Letters Patent of the United States:
A sheet metal radiator comprising a radiator body or primary heating surface, and fins secured thereto and both reinforcing the walls of the radiator body and giving off heat transferred therethrough rapidly to the air, the bodyand the fins being formed of difierent sheet metals and the metal of the fins having a higher thermal conductivity than that of the body, and the fins being secured to the body by rivets of the same metal as and welded to the body.
FRANCIS M. LAMBERT.