US2970812A

US2970812A - Drum type heat exchanger

Info

Publication number: US2970812A
Application number: US591491A
Authority: US
Inventors: Richard W Kritzer
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-06-14
Filing date: 1956-06-14
Publication date: 1961-02-07
Anticipated expiration: 1978-02-07

Description

Feb. 7, 1961 R. w. Kran-2ER 2,970,312

DRUM TYPE HEAT ExcHANGx-:R

Filed June 14, 1956 2 Sheets-Sheet 1 Z2 Feb. 7, 1961 R. w. KRITZER DRUM TYPE HEAT EXCHANGER 2 Sheets-Sheet 2 Filed June 14, 1956 iinited States Patent() DRUM TYPE HEAT EXCHANGER Richard W. Kritzer, Chicago, Ill. Peerless of America, 5830 N. Pulaski Road) Filed June 14, 1956, Ser. No. 591,491

1 Claim. (Cl. 257-241) The invention relates to a heat-exchanger of the drumtype which includes spirally coiled tubing and fins, and the fabrication thereof.

One object of the invention is to provide a heat-exchanger of this type which can be expeditiously and economically fabricated.

Another object of the invention is to provide an improved method of fabricating heat-exchangers of this type.

Other objects will appear from the detail description.

The invention consists in the many novel features hereinafter set forth and more particularly by the claim at the conclusion hereof.

In the drawings:

Fig. 1 is a plan view of an exchanger embodying the invention, the drurn or casing being shown in section;

Fig. 2 is a section taken on line 2 2 of Fig. l;

Fig. 3 is a perspective view of a portion of the finforming structure or strip;

Fig. 4 is a section on line 4-4 of Fig. 1; and

Fig. 5 is a section taken on line 5 5 of Fig. 1.

The invention is exemplified in a heat-exchange unit which comprises: a drum or casing whichincludes a sleeve or hub and an annular jacket or drum 11;- a series of three coils of

tubing

12, 13 and 14, of cylindrical cross section, each including spiral convolutions in side-by-side relation and spaced apart radially. A header 16 is communicatively connected to the inner end of the coils adjacent sleeve 10 and a header 17 is communicatively connected to the outer ends of the coils for the circulation of a fluid, usually a refrigerant, through the coils, one of the headers serving as an inlet and the other as an outlet for the fluid. The radial spacings olf the convolutions of the coils form a spiral passage between the convolutions of the coils for the flow of air longitudinally through the drum or casing. An air impeller (not illustrated) is usually mounted over the coils and driven by an electric motor which may be mounted in the sleeve 1li for forcing air to be cooled through the drum, as well understood in the art.

An elongated or continuous strip of fin-stock, such as thin sheet aluminium, is fabricated into a fin-structure, generally designated 1S, which fits and is confined in the spiral space between the convolutions of the series of coils. This iin-structure is utilized to transfer heat from the fluid in the coils to the air which contacts said structure and the tubing. The fin-structure includes a series of substantially coplanar lin-sections 20 which are adapted to extend across or span the spiral space between the convolutions of the entire series of coils and integral ends 21 which are formed by bends which alternately connect opposite ends of contiguous sections 20 and function as seats for the coils of tubing. Each end 21 includes substantially flat portions 22 and curved portions 23 which conform to the cross-sectional contour of the tubing for closely fitting contact between the outer faces of ends 21 and the convolutions of the coils. Each tin-section 20 has an end 21 provided with seats for the outer pethe sleeve.

ripheral portions of one convolution of each of the

spiral coils

12, 13 and 14, and an opposite end 21 provided with seats for the inner portions of the next convolutions of the coils, the strip forming the fin-structure being of sufficient width for that purpose. The structure 2li before assembly with the coils is readily flexible into generally spiral contour to conform to the spiral convolutions of the c-oils, and, after said assembly, provides fins in the air stream between said convolutions. The tubing of the coils is bendable spirally around the fin-structure to produce pressure-contact between the seats on the ends 21 of the fin-structure and Athe contacting portions of the coils. The faces of sections 20 and inner faces of ends 21 are exposed to the air stream through the drum. In shaping the strip of fin-stock into the continuous structure 15, and bending the metal in the ends 21 to form the seats for the tubing, the metal is ruptured as at 24, at the crests of the curved portions 23. This provides for ilexibility in said curved portions to conform to the crosssectional contour of the contiguous tubing, and also provides openings for the flow o-f air to the clearance between the coils which are in side-by-side relation.

A portion of the inner convolution of each of the

coils

12, 13 and 14 extends around a portion of the sleeve 10 and thence spirally around to the adjoining end of the next convolution where the inner end of the fin-structure is located. A first elogated tapered batlle 30 closes the gap between sleeve 10 and the header 16 where said portion of the inner convolutions extend spirally away from This baille extends to the fin-section 20 on the inner end of the spirally coiled fin-structure adjacent header 16. A portion of the outer convolution of each of said coils extends spirally around casing 11. A second elongated tubular baille 31 closes the gap around said portion and the casing 11 and extends circumferentially to the header 17 and the fin-section 20 on the outer end of the fin-structure. These baffles and construction confine the longitudinal air flow through casing to the spirally extending radial spaces between the convolutions of the coils in which the tin-structure is disposed, for contact ing the air with the fin-structure and efficiency in heat transfer.

In the fabrication of the unit, the fin-structure 15 is of sufficient length to extend between the spiral gaps between the convolutions of the coils between the

headers

16 and 17. Before assembly, the fin-structure with the coils or casing is linear and readily bendable into spiral contour because the sections 20 are readily flexible between -the ends 21. This facilitates the flexing of the strip 15 into spiral contour conformably to the coils of tubing. In assembling the unit, the header 16 is fxedly held in the baille 30 which is secured to the sleeve or hub 1t). The tubing for the

coils

12, 13 and 14 which is sufficiently bendable transversely for this purpose, is bent around the sleeve 10 and baille 30 to progressively form the inner convolution of each of the coils. The fin-structure 15 is folded around the outer periphery of said inner convolutions. This bending of the tubing and folding of the finstructure is progressively continued until the coils and fin-structure are entirely assembled in spirally wrapped relation.

The assembled fin-structure and

coils

12, 13 and 14 are pressed together and contracted and while so contracted are inserted sidewise into the drum 11. This contraction secures the ends 21 of the fin-structure in the coils. The concave seats on the ends 21 of the finstructure are interlocked against relative movement coaxially of the sleeve 10 and drum 11, with the header 16 adjacent baille 30 and header 17 adjacent baille 31. The inner ends of the coils are confined by a flange 4t) on one end of sleeve 10 and a ring 41, and the other ends of the coils are confined and held in the drum between a flange ft2-on the drum and a ring 43. The assembled coils and iin-structure are then secured together with pressure contact or in close-fitting relation for eficient heat-transfer from the fluid in the coils to the nstructure. The air passing through the spirall gaps between the convolutions o the coils will Contact the faces of the tins formed by sections 20, the inner faces of bends 21 and the exposed inner face portions of the coils between sections.

The invention exemplifies a heat-transfer element of the drum-type which is eicient in operation and simple in construction and an economical method of fabricating and assembling the unit.

The invention is not to be understood as limited to the details set forth, since these may be modied Within the scope of the appended claim without departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

A drum type heat exchange unit comprising in combination a drum casing including an open-ended tubular centrally disposed hub and an outer cylindrical casing shell concentric with the hub and spaced radially therefrom, a rst tubular header disposed within said outer cylindrical casing shell and in close proximity to said tubular hub exteriorly of the, latter, a second tubular header disposed within said outer cylindrical casing shell and in close proximity to the latter, the axes of said tubular headers extending parallel to the common axis of the tubular hub` andV cylindrical casing shell, a plurality of vertically spaced, superimposed, uniformly involute tubular coils of cylindrical cross section disposed within said drum casing between the hub and casing shell, the inner ends of said involute tubular coils communicating with the interior of said lirst tubular header and the outer ends of said involute tubular coils, corn-i municating with the interior of said second tubular header, the innermost convolutions of said involute coils being partially wrapped around said hub in contiguous relation to a major arcuate portion of the cylindrical surface thereof, the outermost convolutions of said involute coils closely hugging a major arcuate portionof 4 the, inner cylindrical surfaceV of the casing shell, a tirst elongated tapered baille member lling the space existing between the innermost convolutions of said involute coils and the outer cylindrical surface of the tubular hub and partially encompassing said rst tubular header and the hub, a second elongated tubular baflle member filling the space existing between the outermost convolutions of said involute coils and the inner cylindrical surface of said casing shell, and a continuous strip of lin stock disposed between adjacent convolutions of the various involute l'coils and extending in involute fashion from said sec- .ond bale member to said rst baille member, said fin stock providing a multiplicity of closely spaced radially extending lin sections common to and bridging the distance between the adjacent convolutions of each involute coil, the adjacent inside edges of alternate pairs of adjacent n sections being connected together by integral webs of full fm stock height, the adjacent outside edges of other alternate pairs of adjacent lin sections being connected together by integral webs of full lin stock height, each of said webs spanning said superimposed involute coils and being formed with imperforate curved seats in intimate facefto-face contact with the various coil convolutions, the material of each web between adjacent curved seats being ruptured to dene openings through the web, and presenting curved lingers which closely hub the curved wall of the adjacent coil convolutions, thereby lending flexibility -to said curved seats as well as aording intimate heat exchange between the curved seats and theA coil convolutions.

References Cited in the le of this patent UNITEDv STATES PATENTS 1,822,068l Summers` et al Sept. 8, 1931 1,849,396 Baetz Mar. 15, 1932 2,035,665 Palmer Mar. 3,1, 1936 2,164,854 Booth et al. July 4, 1939 2,213,463 Fink Sept. 3, 1940 2,657,018 Simpelaar Oct. 27, 1953 2,716,802 Greer Scpt. 6, 1955 2,820,617 Tadewald Jan. 21, 1958