Sheet Metal Radiator Assembly

Abstract

A multi-plate radiator assembly features a longitudinally spaced series of hollow, generally flat heat transfer plates, each provided with integral formations which afford circulating headers at opposite ends of each plate, the plate and header units being composed of a pair of sheet metal stampings. The two component stampings of each unit differ from one another in that one thereof is formed at its header-affording ends with a male flange of cylindrical shape and predetermined outer diameter; while the other stamping of the pair is formed in axially aligned comparable zones to provide a female cylindrical flange of an internal diameter equaling the O.D. of the male flange of the next adjacent plate and header-forming unit of the series. Successive units are telescopingly associated with one another at the male and female flanges thereof, and a union of male and female flanges is completed and made liquid tight by a copper solder connection.

Parent Case Text

The present application is a continuation of my copending application, Ser. No. 679,398, filed Oct. 31, 1967.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The improved all-stamped sheet metal radiator assembly was specially devised for use in circulating externally of the shell or wall of an electrical transformer the usual oil coolant of the latter, receiving the oil in a hot condition and returning it to the transformer after heat dissipation to the atmosphere.

2. Description of the Prior Art

A radiator assembly of a generally similar nature, used in a similar surrounding, is the subject matter of U.S. Pat. No. 3,153,447 of Oct. 20, 1964 to Yoder and Kaltz. This patent discloses a series of spaced heat transfer plates, each composed of a pair of stamped sheet metal parts, but they are associated by hand welding at opposite ends thereof with separate pre-machined headers at milled communicating openings in the latter. The U.S. Pat. to Maret, No. 1,999,246 of Apr. 30, 1935 shows a header construction of a nature somewhat similar to that of the present improvement.

SUMMARY OF THE INVENTION

Generally considered, the invention resides in an assemblage of pairs of sheet metal plate components, each component stamped to provide liquid circulating control formation and being weld-sealed to one another marginally, as described in the Yoder et al. patent identified above. Each of the component stampings is formed, at outward, vertically spaced ends thereof adjacent and communicating with enlarged mouth and throat debossments with certain header formations. These provide, on one plate, an integral cylindrical female flange or sleeve and, on the other plate, an integral male flange or sleeve, which formations are sized to have a mating interfit. This interfit is between successive plate units and by a copper soldered union, at which they are rigidly connected and sealed liquid-tight.

The soldering is done by applying a thin copper ring or bracelet to the joint of the telescoped flanges, adjacent an exposed end thereof, then placing the assembly in an atmosphere-controlled furnace, which at appropriate heat causes the copper to fuse and flow into the interface area of engagement of the flanges, thus to complete a liquid-tight and strong lapped seam or joint.

The cost of obtaining expensive elongated header pipes or tubes is avoided, likewise the necessity to mill the same to provide openings with which the transfer plates communicate. Nor is it necessary to hand-weld opposite ends of those plate units to the headers about the openings thereof. This, it should be noted, requires a quite heavy section of header tube to take the weld properly. By contrast, the small tubular connector lengths which join the all-stamped structure of the improvement to the transformer may be of relatively thin and inexpensive stock.

There is a significant advantage over the construction of the Yoder et al. patent in terms of low cost and decreased weight, with equal or better performance. It has the great advantage over the header arrangement of the Maret patent, in that the physical manipulations of rolling and the like to unite successive transfer plate sections are avoided. The entire union of the plate sections of the present improvement is effected at a single furnace brazing operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary end elevation, sectioned on a line corresponding to line 1--1 of FIG. 3, illustrating one of the stamped sheet metal, two-part plate components of the improvement;

FIG. 2 is a fragmentary view in vertical longitudinal section on line 2--2 of FIG. 1; and

FIG. 3 is a side elevational view showing a part of the improved multiple-plate unit of the invention as applied to a transformer wall.

DESCRIPTION OF A PREFERRED EMBODIMENT

The radiator assembly of the invention, as generally designated by the reference numeral 10, is shown in FIG. 3 as being weld-connected at 11 to the wall or shell of a transformer 12. The radiator 10 serves in the usual manner to dissipate to the atmosphere the heat of an oil coolant of the transformer, usually by natural draft.

Assembly 10 is constituted by a succession of laterally spaced upright plate units 16, each constituted in its entirety by a pair of relatively thin sheet steel stampings 17, 18, for example, of 18 gauge. A bottom header portion, generally designated 20, of the improved assembly 10 corresponds exactly to an upper header portion (20' (FIG. 3), both portions being weld-connected to the transformer wall at 11 in the manner indicated in FIG. 2. Save for their formations at which they are telescopingly connected and brazed to form the header portions, the plate embossments 17, 18 are identical.

That is, as seam-welded, brazed, or otherwise united to one another at 21 along face-to-face meeting flanges about the periphery thereof, each of the stampings 17 and 18 comprises certain liquid circulating control provisions. These include a mouth embossment at 23 which is of substantial width in the direction transverse of plate 16, a throat embossment 24 directly inwardly of embossment 23, i.e., in the direction transversely away from header 20, and a corrugated or rippled zone 25 between the two throat embossments 24 of the respective plates 17, 18. The plates are preferably seam weld-connected in face-to-face engagement with one another along upright longitudinal weld zones 26 paralleling the ripple formations 25 thus constituting, with the peripheral seam welding at 21, a very strongly braced and rigid construction.

The rippling of plates 17 and 18 is represented by valleys 27 which terminate in depth just short of the seaming of the plates along their flanges (FIG. 3); and the throated and rippled characteristics of the heat transfer plate 16 impart thereto, and to the assembly 10 as a whole, the advantageous heat transfer action which is described in detail in the above identified patent to Yoder et al. That is, briefly, the enlarged manifold mouth, throat and corrugated rippling afford large intake and outflow volume accommodating liquid within the plates without restricting flow in the headers. There is a maximum ratio of exposed internal plate surface to oil volume traversing the plate structure, with a resultant minimum weight of the assembly 10 for a given oil handling capacity.

Reference being had to FIG. 2, each of the embossed stampings 18 on one side of a plate unit 16 is formed to provide an integral female and sleevelike, cylindrical flange 29 merging with its throat embossment 23 through a 90.degree. curve in cross section at 30. On the other hand, each of the other stampings 17 is formed, directly outwardly of its mouth portion 23, with a relatively abrupt radial and annular shoulder 30, from which an integral cylindrical, sleevelike flange 31 extends axially at 90.degree.. The shoulder 30 serves as a stop facilitating and expediting the assembly of the plate units 16 to one another; and sleeve flange 31 is mildly inturned radially about its periphery at 32, also for the purpose of facilitating the assembly operation.

One end of the header portion 20 of assembly 10 is closed by a stamped sheet steel cap 34, preferably of the same 18 gauge thickness as the other stampings. The opposite end of the assembly telescopingly receives a tubular connector length 35 of carbon steel, which is turned to a reduced outer diameter at 36 for a telescoping interfit in the adjacent end plate unit 16 of the assembly.

In accordance with the invention, the outer diameter of the connecting sleeve flange 31 of each plate sub-assembly 16 is but a trifle less than the inner diameter of its female sleeve or flange 29, as well as that of the end cap 34. The outer diameter of the reduced end 36 of connecting tube 35 bears the same relation to the flange 29 of the unit 16 which is directly adjacent.

In producing the assembly 10, its two component plates 17, 18 are united as an individual sub-assembly 16 by seam-welding to one another about the peripheral flanges 21 thereof. Next, the units 16 are assembled in end-to-end succession, as illustrated in FIG. 3, by telescoping the male flange 31 of one thereof snugly into the female flange 29 of the next adjacent one; and the end caps 34 and connector tube 35 are correspondingly associated with the plate 16 at opposite ends of the series of the latter.

A ring or bracelet of copper solder is then applied about the respective telescoped flange component at the exposed joint thereof at which the caps 34 and flanges 29 abut axially against the positioning shoulder 30 of a plate stamping 17. The entire assembly thus far is then placed in a nitrogen atmosphere furnace, in which it is raised to a temperature to melt the copper solder. The latter thereby flows capillarily into the interface between the telescoped sleeve or flange formations, where upon cooling, it effects an entirely leak-proof rugged joint between the stamped components. The brazed joints are indicated in FIG. 3 by the reference numeral 38.

It is seen that the operations of forming and assembling the components of the radiator of the invention are greatly simplified, expedited and reduced in cost, as compared with a previous generally comparable radiator assembly. The material cost of expensive elongated tubular headers is eliminated; it is unnecessary to mill or otherwise machine them to receive the heat transfer plates; and the necessity for individual hand welded connections of the latter to a header is eliminated. Yet the telescoped assembly affords a header construction having a substantially continuous and uninterrupted surface characteristic along its passage portion opposite the rippled and mouth or throat embossments of the stampings.

A rapid telescoping of the caps 34 and components 16 of the improved radiator is made possible by the beveling of flanges 31 of the concealed male sleeve at 32 to facilitate their disposal in the coacting female formations 29; and the provisions of the abrupt shoulder formations 32 also contribute to this end. A simultaneous brazing of all joints eliminates the need for individually rolling or upsetting the telescoped parts to effect a union which may, after all, be of dubious strength or proof against leakage.

Claims

What is claimed is:

1. In an electrical device cooling system using thermosyphonic flow, a heat transfer assembly which is substantially in its entirety of stamped construction, comprising a succession of spaced stamped and generally flat plate units of like hollow cross-sectional shape, each being comprised of a pair of generally similar stampings secured together about perimetral margins thereof and defining liquid flow means between opposite ends of the respective plate units and said succession thereof, said flow means including corrugated riffle formations on at least one of said stampings of the pair disposed between but spaced from at least one of said ends to control the flow of liquid between said ends, and header units at said ends for communication with said system, said units having successive integral connections to said plate units which are integral parts of the stampings of said pairs and constitute a significant part of said header unit, said connections consisting solely of a generally cylindrical, externally exposed female sleeve formation integral with one of the stampings of each plate unit and extending and opening outwardly at an angle to the plane of the latter, a concealed male sleeve formation integral with the other stamping of the same plate unit and extending oppositely outwardly of said female sleeve formation of the latter, said male and female formations being snugly telescoped, respectively, into and onto corresponding female and male formations of units on either side of said same unit, the stamping on which one of said formations is carried having a shoulder adjoining that formation, said shoulder being abutted by the other formation and determining the axial extent to which said formations are telescoped relative to one another, and means providing a fused union of the telescoped and abutted sleeve formations to constitute said header unit, said stampings having outward embossments adjoining the respective male and female formations defining a throat space between the stampings which communicates with the space between said riffle formations, which throat space is of substantially greater width transversely of the stampings than said riffle formation space, and a mouth space communicating said throat space with said header unit, which mouth space is of substantially greater width transversely of the stampings than said throat space.

2. In an electrical device cooling system using thermosyphonic flow, a heat transfer assembly which is substantially in its entirety of stamped construction, comprising a succession of spaced stamped and generally flat plate units of like hollow cross-sectional shape, each being comprised of a pair of generally similar stampings secured together about perimetral margins thereof and defining liquid flow means between opposite ends of the respective plate units and said succession thereof and header units at said ends for communication with said system, said flow means including corrugated ripple formations in at least one of said stampings of the pair disposed between but spaced from said ends, said ripple formations being of reduced hollow cross-sectional width transverse of the plate unit as compared with the remainder of the latter, said units having successive integral connections to said plate units which are integral parts of the stampings of said pairs and constitute a significant part of said header unit, said connections each comprising a generally cylindrical, externally exposed female sleeve formation integral with one of the stampings of each plate unit and extending and opening outwardly at an angle to the plane of the latter, a concealed male sleeve formation integral with the other stamping of the same plate unit and extending oppositely outwardly of said female sleeve formation of the latter, said male and female header unit formations being snugly telescoped, respectively, into and onto corresponding female and male formations of units on either side of said same unit, the stamping on which one of said formations is carried having a shoulder adjoining that formation, said shoulder being abutted by the other formation and determining the axial extent to which said formations are telescoped relative to one another, and means providing a fused union of the telescoped and abutted sleeve formations to constitute said header unit, said stampings having outward embossed formations adjoining the respective male and female formations and defining a throat and mouth space between the stampings which communicates with the header unit and with the interior ripple formations of the plate unit, said embossed formations diminishing in cross sectional width from said male and female formations toward a zone of communication with said ripple formations.

3. The system of claim 2, in which said fused union comprises a brazed connection of said male and female formations to one another at the telescoped interface thereof is carried having a shoulder adjoining the latter, said shoulder being abutted by and determining the axial extent to which the female formation of the adjacent plate unit is received on said male formation.

4. The system of claim 2, in which the stamping on which said male formation is carried has a shoulder adjoining the latter, said shoulder being abutted by and determining the axial extent to which the female formation of the adjacent plate unit is received on said male formation.

5. The system of claim 2, in which said last named means comprises a brazed connection of said male and female formations to one another at the telescoped interface thereof, the stamping on which said male formation is carried having a shoulder adjoining the latter, said shoulder being abutted by and determining the axial extent to which the female formation of the adjacent plate unit is received on said male formation.

6. The system of claim 2, in which said embossed formations include a throat formation communicating inwardly with said ripple formations and of greater cross-sectional width than the latter, and a mouth formation of greater cross-sectional width than the throat formation communicating inwardly with the latter.

7. In an electrical device cooling system using thermosyphonic flow, a heat transfer assembly which is substantially in its entirety of stamped construction, comprising a succession of spaced stamped and generally flat plate units of like hollow cross-sectional shape, each being comprised of a pair of generally similar stampings secured together about perimetral margins thereof and defining liquid flow means between opposite ends of the respective plate units and said succession thereof and header units at said ends for communication with said system, said flow means including corrugated ripple formations in at least one of said stampings of the pair disposed between but spaced from said ends, said ripple formations being of reduced hollow cross-sectional width transverse of the plate unit as compared with the remainder of the latter, said units having successive integral connections to said plate units which are integral parts of the stampings of said pairs and constitute a significant part of said header unit, said connections each comprising a generally cylindrical, externally exposed female sleeve formation integral with one of the stampings of each plate unit and extending and opening outwardly at an angle to the plane of the latter, a concealed male sleeve formation integral with the other stamping of the same plate unit and extending oppositely outwardly of said female sleeve formation of the latter, said male and female header unit formations being snugly telescoped, respectively, into and onto corresponding female and male formations of units on either side of said same unit, the stamping on which one of said formations is carried having a shoulder adjoining that formation, said shoulder being abutted by the other formation and determining the axial extent to which said formations are telescoped relative to one another, and means providing a fused union of the telescoped and abutted sleeve formations to constitute said header unit, said stampings having outward embossed formations adjoining the respective male and female formations and defining a throat and mouth space between the stampings which communicates with the header unit and with the interior ripple formations of the plate unit, said embossed formations diminishing in cross-sectional width from said male and female formations toward a zone of communication with said ripple formations, the male and female formations as thus telescoped and united defining tubular longitudinal header passages through the respective header units which have a substantially continuous and uninterrupted internal surface characteristic along extreme opposite outer portions of the header units.

8. The system of claim 7, in which said embossed formations include a throat formation communicating inwardly with said ripple formations and of greater cross-sectional width than the latter, and a mouth formation of greater cross-sectional width and breadth than the throat formation communicating inwardly with the latter.