US2354865A - Refrigerating apparatus - Google Patents

Description

A. A. KUCHER ETAL 2,354,865

REFRIGERATING APPARATUS Aug. 1, 1944.

'7, 1941- 2 Sheets-Sheet 1 .za

Filed Jan. 1 42 INVENTOR. Avon-MA. 41mm: Aux flJlf tognaek BY Ana 670mm. Ml-ttf'r.

Aug. 1, 1944.

A, A. KUCHER ETAL REFRIGERATING APPARATUS I Filed Jan. 17, 1941 2 Sheets-Sheet 2 INVENTORS. L lull. fir'amuu 440 624mm. W. k arr. 7

ldlklhf A new Patented Aug. 1,1944

OFFICE REFRIGERATIN G APPARATUS Andrew A. Kncher, Oakwood, and Alex A. Mc-

Cormack and Glenn W. Wolcott, Dayton,

Motors Corporation, Day- Ohio; a corporation of Delaware assignors to General ton,

Ohio,

Application January 17, 1941, Serial No. 374,908 2 Claims. 01. 257-140) This invention relates to heat exchangers and particularly heat exchangers formed of sheet metal plates.

- An object of our invention isto provide an improved heat exchanger constructed substantially in its entirety of thin gauge sheet metal plates arranged in secured together pairs to form a compact structure having a maximum of heat transfer surfaces by rendering all portions of the plates except small abutting portions thereof direct'heat flow paths between a fluid within the structure and a medium exteriorly thereof.

Another object of our invention is to provide a heat exchanger of the type wherein a plurality of thin metal plates are fabricated in such a manner that when secured together in pairs to provide a closed fluidpassageway between the groups of plates the 'walls of the passageways are of an improved form or contour which will withstand high pressure.

Another object of ourinvention is to form a heat exchanger from a plurality of thin metal plates secured together in pairs which plates are prefabricated with dimple-like depressions including fiat portions and intermediate connecting portions and wherein all theflat portions. of the plates are in abutting relationand thespaced apart intermediate portions of the plates provide continuously curved or arcuate wall surfaces of fluid passageways between the plates of the pairs thereof for increasing the strength of the walls of the'passageways.

A further object of our invention is provide a condenser for a refrigerating system by abutting portions of thin metal plates of pairs thereof having refrigerant passageways therebetween and securing wall parts of apertures in one plate of one pair thereof to wall parts of apertures in a plate of anotherpair to form spaced headers extending along the length of the condenser, and wherein the secured together walls of the apertures mayform the sole means forlocking the pairs of plates together and for holding the abutting portions of the plates of the various pairs against one another.

,A still further object of our invention is to provide a heat exchanger or condenser of the .7

typeset forth in the preceding objects wherein the sheet metal plates of each pair thereof are provided with dimple-like depressions over substantially theirentire area andwherei-n'the depressions include spaced apart flat portions and with opposed convex wall surfaces for increasing I the strength thereof to withstand high-internal pressure.

Further objects and advantages reside in the 1 cooperation of parts of the structure which facilitate the manufacture and assembly of ourimproved exchanger and inthe novel combination and arrangement to provide a strong efficient unit of low manufacturing costs as will more fully appear in the course of the following description. V

In the drawings:

Fig. 1 is a diagrammatic showing of a refrigerating system having a condenser constructed in accordance with the present invention therein; Fig. 2 is an enlarged fragmentary front view partly in section and partly in elevation of the pairs of plates forming thecondenser shown in Fi 1; h

Fig.3 is an end view of the condenser shown in Fig. 2;

Fig. 4 is an enlarged fragmentary view taken on the line 4-4 of Fig. 2 showing a portion of the face of a plate of one of the pairs thereof in the condenser;

Fig. 5 is a sectional view taken on the line 55 of Fig. 4 showing the contour of walls of Y a passageway formed between the plates of apair of plates of the condenser and showing the locking of the pairs of plates to one'another;

Fig. -6 is a sectional view taken on the line 6-6 of Fig. 4 showing button-like depressions in the plates and passages which connect portions of the passageway between the plates together; and v Fig. 7 is a fragmentary sectional view taken on the line 1-1 of Fig. 4 showing the buttonlike depressions and other contacting portions of the plates of the condenser.

There is shown in Fig. 1 of the drawings, a diagrammatic illustration of a closed refrigerating system wherein a sealedmotor-conipressor curved or arcuate portions intermediate the flat unit I 0 withdraws evaporated refrigerant from an evaporator ll through a conduit l2,'compresses the evaporated refrigerant and forwards the compressed fluid to a heat. exchanger or condenser, constructed in accordance with our invention and generally represented by the reference character It, by way of a conduit l5. Air flowing over or caused to be circulated through condenser I 4 cools the compressed refrigerating fluid and liquefles the same. The condensed liquefied refrigerant collects in the lower portion of condenser H and is directed by a pipe I 6, to;

the evaporator H. A suitable restrictor or restricting device 11 may be employed for controlling the amount of liquid refrigerant entering the evaporator. Starting and stopping of the motor and consequently the compressor of the motor-compressor unit III, is controlled in response to the refrigerating effect produced by the evaporator. Thus, a thermostat bulb I9 is provided in heat exchange relationship with the evaporator and this bulb is connected with an expansible and contractible bellows 2| of a snapacting switch 22, by a pipe 23. Switch 22 controls the opening and closing of contacts inter posed in an electric circuit leading to the unit In. Operation of the motor-compressor unit It under ordinary demands of refrigeration of the refrigerating system subjects the condenser to normal internal pressures and abnormal demands of refrigeration by the refrigerating system or operation of the system during abnor- -mal1y high temperatures causes the interior of the condenser to be subjected to relatively high pressures. The condenser I4 is constructed substantially in its entirety of sheet metal plates to obtain relatively flat wide refrigerant condensing passageways and these plates are as thin as possible to reduce manufacturing costs of the condenser. Thus, the 'platesmust be fabricated 38 are located at the center of four of the dimples to provide strong walls for the refrigerant passageways in order to withstand high internal pressures which frequently occur in a closed refrigerating system.

The condenser 14 is of a box-like form and is pairs of secured together thin metal members or plates. {The plates of each of the plurality of pairs thereof are fabricated or recessed to provide dimples '21 (see Figs. 2 and 4) over substancomposed of a plurality of long relatively narrow tiallytheir entire surface. area. The plates are all recessed in the same direction and one plate 28 is reversely placed against another plate 29 to form two-plate airs and these pairs of plates are disposed one against another to provide a condenser structure or heat exchanger of the desired length. One plate 28 of each pair thereof is slightly larger than the other plate 28 of the pair and has its peripheral edge portions 3| bent over the peripheral edges 32 of plate 29. Each plate 28 and 28, of the pairs of plates, is provided with an aperture therein adjacent each end thereof. The walls 33 of the apertures in plates 28 are flanged inwardly of the pairs and the walls 34 of the apertures in plates 28 are flanged out- 21 to thus provide the narrow communicative passages 38 between the wider portions of the closed passageway formed by spaced apart flat portions 38 of the dimples. The spaced apart flat portions 36 of one plate 28 of a pair of plates 28 and 28 engages or abuts the corresponding spaced apart flat portions 38 of the adjacent plate 23 of another pair of plates. The portions ll of the dimples 21 provide continuously curved or arcuate wall surfaces for the passageway between the plates 28 and 28 and, between the secured to- I gather points 31 and 38 of the plates and the space between the dimpled depressions 21. of the pairs of plates, form a plurality of air passages 48 extending transversely through the heat exchanger. It will be noted that a relatively flat wide confined fluid passageway is provided between the plates 28 and 29 of each pair thereof and that the securing of walls 33 and 34 of the apertures in the plates provide spaced apart headers extending along the, length of the exchanger and communicating with each of the closed fluid passageways. The continuously curved or opposedconvex wall surfaces ll for the fluid passageway between the plates of'each pair of plates affords a wall structure for the passageway which is of increased strength ,and capable of ,with'- standing high pressures. This increased strength is obtained by formin all portions of the walls of the passageways, except the abutting or secured together portions thereof, with a continuously curved surface or a' surface that is curved in a direction opposite the direction of application of internal pressure thereto. The abutting flat points or portions 36 of the pairs of plates diswardly. The walls 34 of th apertures in plates 23 telescope or fit into'the walls 33 of the apertures in plates 28 (see Fig. 5) and have their edge por tions bent or spun over and secured to theedge portion of the walls 33 to lock the pairs ofplates together. The depressions or dimples 21 in plates 28 and include spaced apart flat portions 38 and intermediate continuously curved orarcuate portions 4|. ,The depressions or dimples 21 are oppositely disposed when the plates 28 and 28 are secured together to provide the pairs of plates- Plates 28 and :s have contacting wall portions 31 (see Figs. 5' and 6). Spaced apart portions of plates 28 and 29 form a relatively flat wide fluid passageway between the plates of each pair thereof and the curved or arcuate portions 4| provide spaced apart opposedconvex wall surfaces for the passageway. The contacting portions 31 of each pair of the plates 28 and-28 are deformed one into tthe other to provide a plurality ofsmall roundinterflttin'g button-like depressions 38 (see Figs. 8

and '1) which provide a mechanical connectiill tribute pressure within any one passageway to other pairs of plates. Thus, the wall surfaces ll and contacting flat points 36 cooperate with one another to provide increased structural strength of the thin plates of the condenser. A relatively heavy plate 42 having a mounting bracket 43 thereon is secured to each end plate of the heat exchanger or condenser 14. One end of each of the headers within the condenser structure I is I closed by a plug H (see Fig; 2) and the other end of each header is provided with a suitable elbow pipe 88 to form a fluid inlet and a fluid outlet for the condenser Id. The plates 28 and 28 of condenser may be individually assembled together with the proper bending of their edges and spinning of walls of the apertures therein and thereafter the structure may be placed in a brazing furnace with a suitable spelter and bonding material located within the passageways and headers of the assembled condenser. The structure will. upon being heated in the furnace, cause, bonding together of contiguous portions of the metal plates 28 and fl. brazing of the plates together is conventional and well known to those skilled in the art and it is to be understood that the end plates 42, plugs 44 and elbow pipe connecting means 88 may be braced to theplates at the'same time the plates are-brazed to one another.

Metal members or plates '28 and 20 are ap-. proximately .012 inch in thickness and the pre- Iabflcatlon thereof with the plurality of dimple- S'uch assembling and metal walls of such thickness.

like depressions I! greatly increases thestructural strength of walls of passageways between the plates over that ordinarily obtainable from of the thin metal as described and their being secured together at their edges and at a plurality of points intermediate their edges and adjacent the dimples 21 prevent the plates from buckling or bulging upon the occurrence of high pressure within the .structure. Abutment of the flat portions 36, of dimples 21 of the plates of one pair of plates, with the corresponding flat portions 36 of dimples 21 of the plates of other pairs of plates, increases the structural strength of the structure in that internal pressure is distributed at a plurality of points and over a wide area to prevent spreading apart of the pairs of plates.

By this construction and arrangement thesecured together wall portions 33 and 34 of the apertures in the plates function or serve to form the sole means of locking the pairs of plates of the structure together. The necessity of providing additional tying means across the length of the structure either internally or exterior] thereof is eliminated.

By fabricating the metal at the contacting points 31 of plates 23 and 29 to form the button- The fabrication over large areas and prevent buckling and bulging of the walls of the fluid passageways to thereby aflord a structure of increased or improved structural strength.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to'be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows: 1. A heat exchanger comprising a bank of pairs of plates, each plate being formed with dimplelike depressions arranged in mutually substantially perpendicular series of rows, the two plates of each pair having their dimple-like depressions in opposed relationship and being spaced apart throughout said rows to provide a fluid passageway between the two plates, the plates of each pair being secured together at theiredges and at points forming rows alternating with the first.

mentioned rows, said depressions having fiat base portions and interiorly convexly curved side portions, the flat base portions of the depreslike depressions 38, we provide a small irregular contiguous surface at the abutting points between the plates of each pair thereof and these surfaces, when bonded together, are strong and 'notllkely to be separated by pressure within the closed fluid passageway between the plates.

.From the foregoing, it will be seen that we have provided an improved heat exchanger and par-- ticularly a-condenser for a refrigerating system which is made' substantially in its entirety of thin sheet metal plates. The condenser is of low manufacturing costs and'highly efllcient since the refrigerant cooling and condensing passagesionsof one pair of plates abutting corresponding flat base portions of the depressions of adjae like depressions arranged in mutually 'substantially'perpendicular series of rows, the two plates of each pair having their dimple-like depressions in opposed. relationshipand being spaced apart ways are flat and wide to spread the refrigerating fluid over a large area and to expose both.

sides of the spread-out-refrlgerant fluid to air flowing through or circulated over tlie condenser. The thin metal sheets with which the condenser is constructed can be readily punched and fabricated and thereafter brazed-together in plurality of interconnected closed fluidpassageways. Our improved condenser is compact and eflicient in that it aflords the maximum of heat transfer surface within a given area and provides for. an eii'ective flow of air overthe-fluid passageways thereof. Contacting portions of the plates of the condenser rapidly transfer heat from one portion to another portion thereof to dissipate the heat to the atmosphere and thereby throughout said rows to provide a fluid passageway between the two plates, the plates of each pair being secured together at their edges and having nested portions diagonally between the a bank comprising pairs of the sheets to form the dimples of adjacent rows, each of said depressions having a flat base portion and an interiorly convexly continuously curved side portion, the

flat base portions of the depressions of one pair of plates abutting corresponding flat base portions of the depressions of adjacent pairs ofplates, the dimple-like depressions in said rows in each plate being contiguous to one another and the curved side portions of the depressions in each pair of plates. thereby providing opposed interiorly convex wall surfaces for said fluid pasreduce the temperature gradient between portions of the condenser. The contacting portions of the plates together with the continuously curved wall portions of the dimples adjacent the con- 'W portions thereofdivide internal pressures sageway continuously along said rows between the wall surfacesthereof provided by the flat base portions of the opposed spaced apart dimplelike depressions in each pair of plates.

ANDREW A. sun: A. McCORMACK. Ginsu w. wonco'rr.

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