US2469828A

US2469828A - Evaporator unit

Info

Publication number: US2469828A
Application number: US676939A
Authority: US
Inventors: Bernard C Johnson
Original assignee: Houdaille Hershey Corp
Current assignee: Houdaille Hershey Corp
Priority date: 1946-06-15
Filing date: 1946-06-15
Publication date: 1949-05-10
Anticipated expiration: 1966-05-10

Description

@y w, i4. c. .JOHNSON ,46, maremma mm Filed June 15, 1946 2 sheets-sheet 1 vyjanr @ffm/imo Jann/30N Patented May l0, 1949 EVAPORATOR UNIT Bernard C. Johnson, Mundelein, lll., assignor to I Houdaille-llershcy Corporation, Detroit, Mich., a corporation of Michigan Application June 15, 1946, Serial No. 676,939

8 Claims.

This invention relates to heat exchangers having ducts so arranged as to efficiently distribute fluid for heat exchange relation with the surrounding zones. Specically the invention relates to an evaporator unit construction wherein diagonal ducts are used in intersecting relation to provide 'a grid-like arrangement which will handle relatively large volumes of refrigerant and avoid the necessity for heretofore used header ducts of relatively large cross sectional area. Thel invention also includes an arrangement of ducts in an L-shaped plate to provide a refrigerated shelf for the evaporator unit as well as a refrigerated back wall for the unit which will absorb residual cooling capacity of refrigerant leaving the unit to dry the refrigerant and prevent frosting of the exhaust tube.

The evaporator units of this invention are preferably formed from embossed secured together contiguous metal sheets bent in the shape of a U to define the bottom and side walls of a sharp freezing chamber. The outer sheet is embossed to provide an inlet manifold duct longitudinally along the bottom wall. Distributing or feeding ducts extend at spaced intervals laterally from the manifold duct and thence upwardly into the lower ends of the side `wallsof the unit. The upper ends of the side walls of the unit each have two superimposed longitudinally extending outlet manifold ducts connected at their front ends. The lower outlet duct of each pair has depending spaced collecting ducts aligned with the upstanding portions of the distributing ducts. Criss-crossed diagonal ducts connect the upper ends of the distributing ducts with the lower ends of the collecting ducts. These diagonal distributing ducts intersect each other to provide a grid-like duct system accommodating large volumes of refrigerant in good heat exchange absorbing relationship with the surrounding zone.

The ducts, because of the large volume capacity afforded by the intersecting grid-defining arrangement need not have large cross-sectional areas to accommodate large volumes of refrigerant and shallow embossments on the outer sheet only are sufcient to define these ducts. As a result, the sharp freezing chamber is free from any protuberances to have increased storage capacity and the outer surfaces of the unit vare 2 free from large protuberances to accommodate mounting -of the unit close to the Walls of a refrigerator cabinet if desired.

The U-shaped unit has an L-shaped wall member composed of embossed secured-together contiguous metal sheets mounted therein to provide a horizontal shelf and a back Wall. Refrigerant is supplied through ducts in the horizontal shelf portion to a transfer tube at the rear end of the unit which supplies the inlet manifold duct in the bottom of the unit. The top outlet manifold ducts in the vtops of the side walls of the unit discharge through tubes at the back of the unit into ducts provided in the back wall portion of the L-shaped member. These ducts are arranged with sumps so that any remaining heat absorbing capacity of the spent refrigerant is utilized to cool the back wall of the unit before the refrigerant is returned to the compressor and condenser of the refrigerating system. In this manner the back Wall acts as a refrigerant drying device to prevent frosting of the refrigerant return tube and to increase the elciency of the unit by causing it to utilize all of the heat absorbing capacity of the'refrigerant.

It is then an object of this invention to provide a sheet metal type heat exchanger free from chambers of large cross sectional areas and having an efficient duct system which places substantially all of the heat exchange liquid flowing through the unit'in good heat exchange relationship with the walls of the unit.

Another object of this invention is to provide an embossed sheet metal refrigerant evaporator unit free from heretofore used large diameter header ducts and having a duct distributing sys.

tem which effectively places all of the refrigerant flowing through the unit in extended surface contact with the duct walls to increase the heat absorbing capacity of the refrigerant.

Another object of this invention is to provide a U-shaped sheet metal evaporator'unit for mechanical refrigerators wherein the side walls of the unit are embossed to have an arrangement of inteisecting diagonally extending shallow ducts defining refrigerant' spreading conduits ofv enhanced capacity.

Another object of the invention is to provide a. heat exchanger with a series of intersecting ducts presenting a grid-like appearance and effective to distribute heat exchange uuid in emcient heat exchange relation with the walls of the unit.

A still further object of the invention is to provide a sheet metal heat exchanger adapted for use as an evaporator unit in a mechanical refrigerator having an L-shaped member mounted therein providing a shelf and a back wall and arranged to receive heat exchange fluid there through.

A still further object of the invention is to provide an evaporator unit for mechanical refrigerators wherein contiguous metal sheets form the back wall of the unit and are embossed to define refrigerant "drying ducts receiving spent refrigerant from the unit. v A

Other and further objects of the invention will be apparent to those skilled in the art from the following detailed description of the annexed sheets of drawings which, by way of a preferred example illustrate one embodiment of the invention.

On the drawings:

Figure 1 is a side elevational view of an evaporator unit according to this invention.

Figure 2 is a front end elevational view of the unit of Fig. 1.

Figure 3 is a top .plan view of the unit of Figs. 1 and 2.

Figure 4 is an enlarged fragmentary horizontal cross sectional view taken along theline IV-IV 'of Fig. 2.

As shown on the drawings:

In Figs. 1 to 4 the reference numeral I0 designates generally a sheet metal evaporator unit according to this invention. The unit I is composed of embossed brazed or welded togethercontiguous metal sheets or plates including an inner sheet I I and an outer sheet I2. The sheets II and I2, after being secured together, are bent so as to provide a bottom wall portion Illa, spaced opposed vertical side wall portions, IIl'b, Illb, and

inturned horizontal top fianges IIlc. Illc at the upper ends of the side wall portions Ib, Ib. These flanges |0c, Ic have apertures I3` therein as best shown in Fig. 3 to receive studs or mounting bolts for suspending the unit i0 in the top portion of a refrigerator cabinet (not shown).

A shelf and back wall unit I4, composed of contiguous Welded together embossed metal sheets or lplates I5 and ||i is mounted in the chamber C defined by the unit I0. The member I4 is bent into the shape of an L and has a horizontal leg I4a providing a shelf in the unit I0 together with a vertical leg |4b providingia back wall for the unit I0. f

Angle brackets I1 are provided to mount the member I4 in the unit I0. As best shown in Fig. 2 these brackets have vertical legs Ila attached to the side walls I 0c of the unit III near the tops of the side walls, together with horizontal legs Hb extending into the chamber C in spaced parallel relation under the anges Ille. Rivets, such as I8, are provided to connect the legs Ila. to the side walls IIIb as best shown in Fig. 1. The horizontal leg |4a of the member I4 rests on the horizontal legs |1b of the brackets I1 and rivets, such as I9, are provided to connect the member I4 to the bracket. As shown in Fig. l brackets I1 are provided at the front and rear ends of the side wall IIlb.

As best shown in Figs. 1 and 2, the outer sheet or plate I2 of the unit II) is embossed to provide an inlet manifold duct 20 along the bottom Illa midway between the side walls IIlb. This duct 20 extends longitudinally from the rear portion to the front portion of the unit and has a closed end 20a, in spaced relation from the front edge of the unit, together with an enlarged end 2U!) in spaced relation from the rear edge of the unit.

Feeder ducts 2| are also embossed in the outer plate or sheet I2 and extend laterally outward from the inlet manifold duct 20. These ducts 2| are in spaced parallel relation and traverse the entire bottom I0a of the unit and extend around into the side walls of the unit to levels just above the rounded corners between the side walls and bottom. 'I'hese feed ducts 2| serve to distribute refrigerant from the inlet manifold 20 to the side wall portions |0b of the unit IIJ at equally spaced intervals along ther lengthv of the side walls.

Embossments are provided in the outer sheet I2 near the tops of the legs or side walls IIlb to define in each leg or side wall a pair of superimposed longitudinal outlet manifold ducts, including a bottom duct 22 and a top duct 22a.

`The

ducts

22 and 22a are connected at the front end of the side wall by a duct 22h.

The outer sheet I2 is further embossed to provide spaced upstanding collecting ducts 23 depending from the outlet manifold ducts 22 in the upper portions of the side walls |0b of the unit. These collecting ducts 23 as best shown in Fig. 1 are aligned with upper ends of the feeder ducts 2|.

The outer sheet I2 is still further embossed in the side Wall portions IIlb thereof to define criss-crossed diagonal or sloping heat exchanger ducts 24 connecting the upper ends of the feeder ducts 2| with the lower ends of the collecting ducts 23. These sloping ducts 24 are so arranged that two ducts 24 diverge from each duct 2| and 23 except at the end ducts 2| and 23. The ducts 24 intersect each other at points 24a to define a grid-like design in the side walls I0b with diamond-shaped flat sheet portions D bounded by duct-defining beads or embossments. The sloping ducts 24 extending from the end ducts 2| and 23 slopediagonally inward and converge with an oppositely sloping duct at their other end. Outwardly sloping ducts 24 which would normally diverge beyond mating relation with the distributing or collecting ducts 2| or 23, mate with each other at points 24h at the front and rear portions of the side walls 0b.

Refrigerant from the feeder ducts 2| is distributed throughout substantially the entire faces of the side walls |0b of the unit by the grid-like arrangement of sloping ducts 24 and at the same time the ducts 24 only have semi-cylindrical cross sectional areas as best shown in Fig. 4. The labyrinth passages provided by the ducts afford ample capacity for relatively large volumes of refrigerant without collecting the refrigerant in any chamber of large cross sectional area. As a result the refrigerant is maintained in excellent heat exchange relation with the sheets and I2.

Since the ducts 20 to 24 are all defined by embossments in the outer sheet I2. the chamber C enclosed by the unit I0 is free from inwardly protruding embossed portions and will have increased storage space.

The shelf portion I4a of the member I4 has the bottom sheet I6 thereof embossed, as shown in Fig. 3, to provide a serpentine duct 25 which extends from an upstanding inlet collar 26 formed on the upper sheet I4a at the rear end of the shelf forwardly vand rearwardly in a series of coil-like turns to an upstanding outlet flange 21 transversely aligned with the collar 26. An inlet tube or fitting 28 is brazed in the flange 28 to supply refrigerant to the duct 25. An outlet tube or fitting 29 is brazed or otherwise secured in the flange 21 and is connected by means of a tube 30 with the enlarged portion 20h of the inlet manifold duct 20. Refrigerant thus is introduced through the shelf portion Ida to the rear end of the'mani- These upstanding legs are at the rear end of the` shelf. 1

The back wall-defining portion or vertical leg AMb ofthe member I4 has the inner sheet I6 thereof embossed to define spaced parallel vertical ducts 3l as best shown in Fig. 2. The top ends of the two innermost ducts 3| are connected by a horizontal duct 32 embossed in the outer or back sheet l of the leg Mb. The duct 32 has an outwardly extending cylindrical flange portion 33 embossed thereon and receiving an outlet tube or fitting 34. This ange 33 is midway between the ends of the duct 32.

The lower ends of adjacent ducts 3l are connected by a pair of superimposed parallel ducts 35 embossed in the outer or rear sheet l5 of the member I4 near the bottom of the back wall Mb. The lower ducts 35 of each pair provide collecting sumps for unspent refrigerant while the flow of spent refrigerant is unimpeded through the upper ducts 35. The unspent refrigerant in the lower ducts 35 soon becomes exhausted since it is in excellent heat transfer relation with the refrigerated space surrounding the unit and, when exhausted, it is drawn upwardly into'the duct 32 through the innermost ducts 3|.

'I'he top ends of the outer ducts 3l have rearwardly extending cylindrical flanges 36 receiving tubes or fittings 3l connected at their upper ends to cylindrical flanges 38 extending inwardly fromthe rear ends of the outlet manifold ducts 22a.

Refrigerant is thus collected from the outlet ducts 22a by the tubes 31 and flows in a serpentine path through the ducts 3l and 35 to the center of the back wall Mb. These ducts 3l and 35 provide a dryingvtube and sumps for the refri-gerant to afford additional heat-absorbing surfaces through which the spent refrigerant from the outlet manifold 22 must'pass before it reaches theexhaust'tube 34.

From the above description it should be understood that the heat exchanger or evaporator unit of this invention is free from enlarged header chambers and has a drying circuit made as a part of the back wall of the unit in a member supported by the unit and also providing a shelf in the unit. The criss-crossed diagonal or sloping distributing ducts are formed by shallow embossments on the outer surfaces only of the unit but due to their intersecting grid-defining arrangement, have large capacity without at .any time collecting the refrigerant in a chamber of large cross-sectional area. 'I'his arrangement maintains the refrigerant in relatively small diameter flowing columns to have increased heat exchange relationship with the walls of the unit. The elimination of headers which heretofore projected into the storage space C of U-shaped refrigerator units creates increased storage space for ice trays and the like in the units of this invention. The superimposed

outlet manifold ducts

22 and 22a are connected at their front ends and the top duct is exhausted out of its rear end so that refrigerant being removed from the unit must traverse the entire length of the unit. This arrangement prevents any short circuiting possibilities which might produce warm or defrost areas on the unit especially at the upper front corners of the unit.

The use of shallow embossments only on the outer faces of the unit accommodates mounting the unit close to the walls of a refrigerator cabinet, thereby conserving cabinet space. The units of this invention are especially satisfactory for mounting in an upper corner of the storage space of a refrigerator cabinet.

It will, of course, be understood that various details of construction may be varied through aV wide range without departing from the principles of this invention and it is, therefore,not the pur pose to limit the patent granted hereon otherwise than necessitated by theiscope of the appended claims.

I claim as my invention:

1. A heat exchanger comprising contiguous secured together U-shaped metal sheets forming the bottom and side walls of a chamber, at least one of said sheets being embossed to dene a. longitudinal inlet manifold duct along the bottom, feeding ducts extending laterally from the manifold duct and thence upwardly into the lower ends of the side walls, oppositely sloping ducts extending upwardlyv from the upper ends of the feeding ducts and the oppositely sloping ducts extending from one of said feeding ducts each intersecting with a plurality of the other sloping ducts to form a grid-like pattern on the side walls, upstanding collecting ducts at the upper ends of the oppositely sloping ducts, and longitudinal outlet ducts. at the upper ends ofthe collecting ducts, contiguous secured to gether L-shaped metal sheets mounted in said chamber to provide a shelf and a back wall and having a shelf duct and a back wall duct, means for vintroducing fluid into the shelf duct, a tube connecting said shelf duct and the inlet manii fold duct, tubes connecting the longitudinal outlet ducts with the back wall duct, and an outlet tube for exhausting said back wall duct.

2. A heat exchanger comprising inner and outer contiguous metal sheets secured together along contacting faces thereof and bent into U-shape to provide the bottom and side walls of an enclosed space, said outer sheet being embossed to define a longitudinally extending inlet duct along the bottom, a plurality of spaced feeding ducts extending `laterally outward from the inlet duct along the bottom and thence upwardly into the lower portions of the side walls, longitudinally extending outlet ducts in the `upper ends of the side walls having a plurality of depending collecting ducts and criss cross oppositely inclined diagonal ducts in a grid-like arrangement in the side walls communicating at their lower ends'with the upper ends of the feeding ducts and at their upper ends with the depending collecting ducts of said outlet ducts whereby heat exchange fluid introduced into. the inlet manifoldxwill be distributed in a plurality of -individual ducts to the lower ends of the side walls of the heat exchanger and will thence flow in a multitude of criss crossed paths to the upper ends of the side walls for removal through said outlet ducts.

3. An evaporator unit for mechanical refrigerators or the like which comprises contiguous secured together embossed metal sheets bent to define a sharp freezing chamber and embossed to denne a single inlet manifold duct, a plurality of feeding ducts extending in spaced relation from opposite sides of the inlet manifold duct and a plurality of oppositely inclined distributing ducts communicating with the feeding ducts and arranged in a grid-like pattern to distribute refrigerant along a labyrinth arrangement of paths each of relatively small cross sectional area to enhance heat transfer from the refrigerant to the walls of the unit, and an outlet manifold duct communicating with the upper ends of the distributing ducts.

4. An evaporator unit comprising contiguous secured-together embossed metal sheets bent into U-shape to provide bottom and side walls for defining a sharp freezing chamber, at least one of said sheets being embossed to define an inlet manifold duct extending longitudinally along the central portion of said bottom from the front to the rear of the unit, a plurality of laterally extending feeding ducts in spaced vrelation along the bottom of the unit and continuing around the bottom corners of the unit into the side walls of the unit, criss-crossed oppositely sloping sets of refrigerant-spreading ducts in said side walls diverging from the upper` ends of the feeding ducts-spaced parallel upstanding collecting ducts at the converging upper ends of the diagonal ducts to receive refrigerant therefrom, lower longitudinally extending outlet manifold ducts receiving the upper ends of the collecting ducts and upper longitudinally extending manifold ducts spaced above said lower manifold ducts and connected therewith at the front ends of the side walls, an L-shaped member composed of embossed contiguous secured-together metal sheets in said sharp freezing chamber carried by the side walls of said unit to provide a shelf and a back wall for the unit, said shelf portion of the member having a duct for refrigerating the shelf, a refrigerant inlet connected to one end of said shelf refrigerating duct together with a refrigerant outlet at the end of the duct remote from the inlet end thereof, a tube connecting said outlet with said inlet manifold of the unit, said back Wall portion of the member having refrigerant ducts therein with an outlet. at the central portion thereof and with inlets at the outer end portions thereof, said back wall refrigerant ducts having bottom sump ducts between the inlets and outlet, and tubes connecting the rear ends of the upper outlet manifold ducts of the unit with the upper outer end portions of the refrigerant ducts in said back wall portion.

5. A sheet metal evaporator for mechanical refrigerators comprising a U-shaped unit having duct containing side walls and a duct containing bottom, an L-shaped duct defining member mounted in said U-shaped unit to define a horizontal shelf with a first set of ducts and a vertical back wall with a second set of ducts, means for introducing refrigerant into the first set of ducts, a tube connecting said first set of ducts with the ducts in said bottom, and tubes connecting the ducts in said side walls with the second set of ducts to dry refrigerant exhausted from the unit in said vertical back wall before the refrigerant leaves the evaporator.

6. An evaporator unit comprising a U-shaped member defining a sharp freezing space and having refrigerant-distributing ducts in the walls 8 thereof with outlets -at the upper ends ofthe side legs, an L-shaped member in said U-shaped unit having a horizontal leg providing a shelf in the sharp freezing space enclosed by the unit and a,

vertical leg depending from said horizontal leg forming a back wall for the unit. said vertical leg having ducts therein with upstanding portions connected at their lower ends by spaced superimposed horizontalducts, and transfer tubes connecting the outlets of the ducts in the unit with the ducts in the back wall of the L-shaped member.

7. An evaporator unit comprising contiguous secured-,together embossed metal sheets bent into U-shape to provide a bottom wall and side walls for deflning a sharp freezing chamber, at least one of said sheets being embossed to define an inlet manifold duct extending longitudinally along the central portion of said bottom from the front to the rear of the unit, refrigerant-spreading ducts in at least one side wall, means providing communication between said refrigerant-spreading ducts and said inlet manifold duct, a longitudinally extending outlet manifold duct in at least one side wall, means providing communication between said refrigerant-spreading ducts and said outlet manifold duct, an L-shaped member composed of embossed contiguous secured-together metal sheets in said sharp freezing chamber carried by the side walls of said unit to provide a shelf and a back wall for the unit, said shelf portion of the member having a duct for refrigerating the shelf, a refrigerant inlet at one end of said shelf-refrigerating duct, a refrigerant outlet at the other end of said duct remote from the inlet end thereof, means connecting said refrigerant outlet with said inletv manifold duct of the unit, said back wall portion of the member having refrigerant ducts therein with at least one inlet and outlet, said back wall refrigerant ducts having bottom sump ducts between the inlet and outlet, and means connecting the rear end of the outlet manifold duct of the unit with the inlet of said refrigerant ducts in said back wall portion, whereby refrigerant circulates through said shelf-refrigerating duct, through said inlet manifold duct, through said refrigerant-spreading ducts in said side wall, through said outlet manifold duct, and into the refrigerant ducts in said back wall portions, through the bottom sump ducts, and through the outlet of said refrigerant ducts in said back wall portion.

8. An evaporator unit comprising contiguous secured-together embossed metal sheets bent into U-shape and having an embossed longitudinally extending duct in at least one of the upper ends of the side legs, a back wall on said unit composed of embossed secured-together metal sheets having a first duct therein with an upper inlet end adjacent said one side leg, a second duct having an upper outlet end remote from said one side leg, superimposed parallel ducts at the bottomof said back wall, one end of each parallel duct being connected with said first duct, the other end of each parallel duct being connected with said second duct, an outlet tube communicating with the outlet end of said second duct in the back wall, and a transfer tube connecting the rearend of the upper longitudinally extending duct in said one side leg of the unit with the inlet end of the first duct in said back wall.

BERNARD C. JOHNSON.

(References on following page) REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Number Name Date Newman June 13, 1939 Steenstrup Maan-11, 1941 Raskin June 3,1941 Beane May 23, 1944 Johnson Oct. 9, 1945 FOREIGN PATENTS Country Date Great Britain June 21, 1906