US2908149A - Evaporators for refrigeration - Google Patents

Description

J. A. HALL EVAPORATORS FOR REFRIGERATION 3 Sheets-Sheet 1 Filed July so, 1958 Fig.5

INVENTOR. M /Al...

J. A. HALL EVAPORATORS FOR REFRIGERATION Oct. 13, 1959 3 Sheets-Sheet 2 Filed July 30, 1958 Oct. 13, 1959 J. A. HALL 2,908,149

EVAPORATORS FOR REFRIGERATION Filed July 30. 1958 3 Sheets-Sheet 3 INV EN TOR.

' T/AA leak-d7,

EVAPORATORS FOR REFRIGERATION James A. Hall; Detroit, =Mich., assignor to Reynolds Metals Company; Richmond, Va., a f corporation of Dela-- ware Application July 30; 1958; S'erial N'o'; 152,144 2-Claims.- (Cl.62-516) This invention relates to arefrigeratlon 'evaporatorof" the compartment'type commonly employed in? household refrigerators; The present invention isia continuationin-part" of my copending' application SerialNo; 434,560, filedJune 4, 1954, now abandoned.

The object-off this invention is to provide a compartment-type evaporator which is relatively inexpensive to construct and'highly efiicient and trouble free in oper ation.

Iii accomplishing this object of the invention, I start with an expandedpassageway panel of any suitable type, preferably'the roll 'bondedtype exemplified by. thelong U.S. Patent #2,662,273, bend it into a tunnel-like structure which is open at its front end (or .at both ends) and which otherwise has atop-wall, opposite side walls-: integral with the top wall and a--bottonr-wall,- However, before forming the-panel, I lay outthe passageway sys tem on the original panel-blanks inamanner suchthat the completed panel will havea plurality; of seriallyconnected accumulator chambers or pockets 'withalternate 'Fig; 2 is a perspective-view-showing=itheopposite side and top. ofthe embodiment shown in Fig} 1; 1

Fig." 3isa' plan view-of the flat blank; formed with flow passages, a grid ofevapora'tor passages, and accumulator pockets, the transverse dotted lines indicating 'foldlines;- Fi'g; 4 is a bottom view'of the structure shown in Figs; land 2; and

Fig". Sis-Ban enlarged sectional vieWtaken on=-the"line' s- 5 'of Fi 4;

Referringto Figs. '3 and 5, it will be understood that the passageway panel structure is preferably formed' "of two sheets of metal; preferably aluminum, which "are bonded or welded together in='face-to face relation exceptat areas which define the new tubes and accumulator wells. Thus, inFig. 5, a tube shown ml is provided by bulging one of the two'sheets, which havebeefbonded together in face-to-face relation, at allareas except at the required tubular areas, the areas of bond virtually forming an integral metallic body. In -Figs 5," the dotted'line at 2 indicates the normal division line'between the sheets, but this line disappears when roll-bonding or-pressure welding is employed to unite the twosheets, intoan'integral structure. Before the roll bondihg of the: two sheets, there is applied to the face'of one sheet; or to the corresponding-faces of both sheets, a pattern of 3a. suitable resist, this pattern, in the embodiment shown, defining 2,908,149 Patented Oct. 13,, 1959 2; the"tubeand"the'accuinulator pocket areas illustrated inf Fig. 3.

The resist app'lied'to'form saidpattern mayb'e m'olyb den'um disulfide andcolloidal graphite, the graphite being held in a re'sinbinder, 'or any'oth'er resist havingequiv alent function,- maybe applied. The "patternnlay beep plied by silkscreen printing, by'gr'avure, or otherwise:

In the rollbonding, a"substantialreduction in thickness of" the sheets" is effected; and a" suitable r'o'll bonding method is described in'the'copending application of B. Thomas and James A. Hall, filed A ril 1 27, 1, Serial No'. 4251926, and indie ULSQPatenFNO. 2,662,273 to-Long', issued Dec; 15, 1953. V

Referringparticularly to Fig. 3 when-the blank is bent to form the refrigerator compartment,, the areaTofthe plate or panel between the dotted lines Sand constitute the top' wall of the compartment,.the area between the dotted lines 5 and 6 constitutes the bottom wall ofthe compartment, the areas at- 7 and 8 which are lapped and secured together form one side wall'ofthe compartment (the left side wall as seenin Figs. 1 and 2), and the area. at 9'5: forms the opposite side wall of the-compartments I Reference to Figs. 1, 2 and 4 in relation toFigr 3 will show that in the illustratedembodiment the-refrigerant: liquid introduced at inlet9 flows upwardly into thespar-a allel tubes "10 Whichextend upwardly of the sidewall, then across the topwallof the:boxor compartment C, thencedownwardly at-1'1 :onthe-opposite side wall of the box and thence-at 12 transversely .of thebox bottom, the refrigerant enteringca short tubular lead at Iii-and thence passing int-o the grid ofrefrigerant 1 passagee-l which covers the major area of the said bottorm Refrigerant flows-through the-gridof passages 14 along. thebottomtowardthe side'ofi the box -show-nin Fig. 4,- and =thence upward-Ly; through a short tubular I conduit 15- whichleads to the parallel conduits16;thelattenconduits dischargingthe refrigerant into the first accumulator pocket 17. The'accumulator'pocket- 17 feeds through the tubular conduits ls-to the accumulator pocket 19,- the latterfeeding through :theconduits =20 to the accumulator pocket 21, the-latter feedingathrough' the conduits 22 m the accumulator: pocket -23,- -and the latter dischargin'guto outlet 25 by. means of the tubular :conduits -24:

F rent the foregoing and particularly-from an inspecti'om ofFigs. 1'3, it willbe 'seen= 'that 'th'e accumulator-.means: comprises a succession of" four accumulator chambers of pockets- (17,- 19; 21 and- 23) enclosed with'inthe -sid'e walls defined :in one "sideby areas-7 and -8"=an'd ontthe'. opposite side by area 9d). 'Ihese accumulator pocketsare disposedirrafashionsuch-that; proceeding in' the' directionof :refrigetan-hflow, every; other pocket (17, 121) of :thesuccession;.beginninggwitlwthe first; -is =locatecl on one side wall whil'e eachremaining pocket-(U; 23)of: the succession;- beginning' with: the"seconcl, is located-on the other side wall. Each of said pockets h'as--a-ref1igeram inlet and a horizontally 'spaced outletinitstop. These accumulator pockets are connected in series within' the refrigerant passageway. systenr by:- interposed elongated conduits (16, .18, 20 and 229 =which3-from the first to the. last of said succession, extend across the top wall (the area between. dotted :lines s3nand 4) i and follow a pattern suchthat the outlet of the first :pocket- 17 on one side" wall is" connected by. top wall conduits-18 to 'theinletz of thesecond pocket19 on the other sidewall while the outlet of the second pocket isconnected by-conduit's'ifl to the inlet of the third pocket 21 on said one side wall the" outlet 'ofthe' third pocket being connected 'by/th'e mp, wall 'conduitsZZ-to the'inlet of the'fou'rth' and last pocket 23? Themaxiinumhoriz'ontal widthof each accumulator pocket; in the direction of th'e' thickness of the panel; is substantially" the same I as the maximum width (in 3 panel-thickness direction) of the elongate conduits crossing the top wall. The maximum length of each accumulator pocket,'in a horizontal direction at right angles to its horizontal width, is at least as great as the widest.

horizontal spacing between the centers of its inlet and outlet openings. Thus, for example, the maximum length of the accumulator pocket 17, in a horizontal direction proceeding at right angles to its horizontal width, is

' the vertical depth of each pocket being as above defined,

the volumetric capacity of each pocket necessarily is several times larger than the volume of the inlet conduits discharging into it over a corresponding length of such conduits. As a consequence, each pocket is capable of trapping and holding a substantial quantity of liquid refrigerant during normal evaporator operation.

It will be seen that the accumulator pockets are more or less symmetrically arranged at the opposite sides of the evaporator box. In operation, in some cases, liquid refrigerant may not be evaporated entirely in the bottom grid 14, tubes 15, 16, or preceding tubes to 13, and the vapor and liquid refrigerant flows into the accumulator pocket 17 which traps the liquid and allows the vapor to continue its movement into the tubes 18. Any overflow of liquid in the accumulator pocket 17 is carried or pushed by the vapor into the accumulator pocket 19, and similarly, any overflow of liquid in the accumulator pockets 19 or 21, is carried or pushed by the vapor into the accumulator pocket 23. The amount of liquid. refrigerant which reaches the various accumulator pockets varies, depending on operating conditions, such as, for example, the external atmospheric temperature, the interior temperature, or the heat removal requirements, and the liquid refrigerant level or overflow at the various accumulator pockets thus will vary. Thus, for example, under some conditions, the pocket 23 may be devoid of liquid refrigerant; or the pockets 23, 21 may be empty or partly filled with liquid refrigerant; or the pockets 23, 21 and 19 may be empty or partly filled. Evaporation which occursin these pockets aids in producing the desired low temperature in the compartment, and these pockets also assist in separating liquid refrigerant from vapor so that the vapor discharged at outlet 25 is more or less superheated. The accumulator pockets 17, 19, 21 and 23 may have equal capacity, or some of the pockets following the first pocket 17 may have greater capacity. In Fig. 3, the pockets 19 and 21 are larger than the pocket 17 while the last pocket 23 is larger than pockets 19 and 21. When the accumulator pocket 17 overflows, continued refrigeration by evaporation action occurs in the conduits 18. When there is sufficient refrigerant to fill theaccumulator pocket 19,'and this pocket overflows, continued refrigeration by evaporation action occurs in the conduits 20, and likewise, when the pocket 21 overflows, refrigeration by evaporation occurs in the tubes leading to and from the last accumulator pocket 23.

- The grid 14 of evaporator tubes is fed by the tubular conduits 9, 10, 11 and 12 at the front of' the box, which makes that front area remain cold even when warm air is admitted by repeated opening of the refrigerator door. The greater capacity of the accumulator pocket 23, as illustrated, is to insure that little, if any, liquid refrigerant will go beyond the tubes 24.

Whileit is preferred that the evaporator blank be formed by roll bonding or pressure welding the two sheets,

with resist therebetween at the tubular conduit areas, the

grid, and the accumulator pockets, the evaporator blank alternatively may be constructed by die-forming one or pockets and then brazing or press welding the two sheets together.

While I prefer the use of parallel tubular conduits 10 leading to a single inlet 13 for the grid 14 and parallel conduits 16, 24 leading to and from the accumulator pockets, a single enlarged conduit may be used in each case, if desired. Also, the parallel pairs of conduits 18,

- 20 and'22 may be replaced by single conduits of appropriate dimensions.

In Fig. 5, I have shown tubular expansions at onlyone face of the structure, but the area opposite thereto may be likewise expanded. Thus, when two aluminum sheets are bonded together, both sheets may be expanded at the tubular and accumulator pocket areas. I prefer that the walls of the accumulator pockets b reinforced by uniting the two sheets within the margins ofthe pockets in a waffle-like pattern of welded areas, as indicated in the drawing. 7

Having described my invention, I claim:

1. A refrigeration evaporator comprising: a hollow structure open at the front and composed of a passageway panel constructed of at least two superposed metal sheets bonded together in face-to-face relationship and having a bulged refrigerant-passageway system of unweldedareas.

between them including accumulator means; said structure having a top wall, opposite side walls integral with both of the two sheets withbulging conduits, grid and said top wall and a bottom wall; said accumulator means comprising a succession of at least three accumulator pockets enclosed within said side walls and disposed in a fashion such that, proceeding in the direction of refrigerant flow, every other pocket of the succession, be

ginning with the first, is located on one side wall while eachremaining pocket of the succession, such as the second, is located on the other side wall, each of said pockets having a refrigerant inlet and a horizontally spaced outlet at its top; said accumulator pockets being connected in series Within said refrigerant-passageway system by interposed elongate conduits which, from the first to the last of said succession of pockets, extend across said top wall following a pattern such that the outlet of the first pocket on one side wall is connected to the inlet of the second pocket on the other side wall while the outlet of said second pocket is connected to the inlet of the third pocket on said one side wall; the maximum horizontal width of each accumulator pocket, in the direction of the thickness of the panel, being substantially the same as the maximum width of said interposed elongate conduits in the panel-thickness direction; the maximum length of each accumulator pocket, in a horizontal direction proceeding at rightangles to its horizontal width, being at least as great as the widest horizontal spacing between the centers of its inlet and outlet openings, and the maximum vertical depth of each pocket'being equal to at'least three time its width; and the volumetric capacity of each pocket being several times larger than the volume of a corresponding length of the inlet conduits discharging into it so as to render it capable of trapping and holdinga substantial quantity.

of liquid refrigerant during normal evaporator operation.

2. The evaporator of claim 1 wherein: the volumetric capacities of said pockets, proceeding in the direction of refrigerant flow, increases from a first pocket of minimum capacity to a last pocket of maximum capacity.

I References Cited in the file bf this patent UNITED STATES PATENTS Hall Jan. 17, 1956

Images