US2835114A - Refrigeration apparatus - Google Patents

Description

' y 1958 M. e. SHOEMAKER ET AL 2,835,114

REFRIGERATION APPARATUS Filed March 23, 1956 "v, I'I'I'IAI INVENTORS 444A (0111/ GI J/IOi/l/AAE? Z6 BY 4/408/(5/4- 60F): F76. 2 W

United States Patent Ofilice 2,835,] 14 Patented May 20, 1958 REFRIGERATION APPARATUS Malcolm G. Shoemaker, Doylestown, and Maurice A. Golf, Ambler, Pa., assignors to Philco Corporation, Philadelphia, Pa., a corporation of Pennsylvania Application March 23, 1956, Serial No. 573,537 8 Claims. (Cl. 62-11785) Our invention has to do with refrigerating apparatus of the type having a heat exchanger passageway system incorporated in a unitary metal sheet, suitably cut and bent for installation on and in a refrigerator cabinet. The invention relates particularly to a branch passageway structure, interconnecting certain parts of such a system with auxiliary equipment, installed externally of the passageway-forming sheet. The branch passageway structure of this invention is an improvement on the invention relating to the sheet structure in general, which has been shown and described in the co-pending application of Harold W. Schaefer et al. bean'ng Serial Number 569,635, filed on March 5, 1956, and assigned to the assignee of the present invention.

Said co-pending application discloses certain forms of a unitary sheet and passageway structure, which allow a substantial reduction of fabricating cost in the production of refrigerating apparatus, while at the same time providing a substantial increase of safety and economy in the Operation of such apparatus, by eliminating a great many, if not all, of the tubular fittings and joints which heretofore were required as elements of a refrigerant flow circuit. in practice, however, certain limitations have been encountered, in trying to eliminate some of the fittings external to the unitary sheet. The difiiculty was connected in part with the refrigerant flow restrictor, forming one of the basic parts of such a system. With respect to the integral construction of the restrictor, as such, an improvement has been disclosed in the co-pending application of the present co-inventor, Maurice Goff, Serial Number 573,536, filed March 23, 1956, assigned to the assignee of the present invention. However, a further, largely independent problem has been encountered, with respect to certain required or at least highly desirable, interconnecting structures, interposed between the restrictor of a unitary'sheet metal passage system, on the one hand, and certain refrigerant conditioning units on the other hand. The present invention has to do with such interconnecting structures.

Means for conditioning, particularly for drying and filtering the circulating refrigerant are usually-provided; a dryer being of importance in order to make sure that even traces of humidity, which could freeze in the restric'tor, are removed from the circulating refrigerant. While a dryer, as such, is well known to the art, a particular problem of the composite sheet and passage structures resides in the provision of eflicient incorporation of the dryer in the apparatus as a whole, since on the one hand, any freezing of humidity in an integral restrictor would present a particularly severe case of trouble, and on the other hand it is desirable to minimize external connections to dryers and the like, in order to maintain one of the main advantages of the composite sheet construction. 1

For similar reasons it is desirable to provide an especially suitable connection for the Well known refrigerant filter or screen which serves to remove solid particles from the circulating refrigerant.

Thus it is a primary object of this invention to provide an integral sheet metal and refrigerant passageway structure with an internal three-way joint adapted to interconnect external refrigerant conditioning means with internal refrigerant flow restrictor means and with general internal refrigerant passage means forming part of said system.

Other objects are: to make the joint structure as simple and economical as possible and so to select materials for the different parts thereof as to minimize both operating and fabricating problems.

Still further objects, features and advantages of the invention may be noted upon a study of the detailed disclosure of a preferred embodiment, which follows.

'In the drawing:

Figure 1 is a plan view of a structure incorporating the present invention.

'Figure 2 is an enlarged, fragmentary section, taken 7 along the line 2-2 in 'Figure 1, and

Figure 3 is a section taken along line 3-3 in Figure 2.

As mentioned in said Schaefer et al. application and illustrated in Figures 1, 3 and 9 thereof, it is frequently desirable to provide an intermediate product, in the mass production of refrigerating apparatus of the present type, said intermediate product consisting in a flat, elongated sheet metal blank *Wi'lfh passages therein. The present Figure 1 shows a sheet metal blank 10 forming such an intermediate product. It also shows the refrigerant dryer or conditioner 11, externally connected to the blank in a three-way joint area generally designated by the numeral 12. In addition the figure shows, diagrammatically, the usual compressor 13 and the discharge pipe 14 externally connecting the compressor with the integral passageways in the sheet metal blank. These passageways include a compressor discharge passage 15; a condenser 16; a flow 'resti'ictor 17 formed by a so-called capillary passage; a

series "18 of evaporator/elements 19, 20 and 21; and, as a discharge means for the last evaporator 21, an integral compressor suction passage 22, desirably extending adjacent and parallel to the capillary passage 17 and to a longitudinal edge 23 of the sheet. The circuit is completed by an external compressor suction pipe 24.

It is believed to be unnecessary to describe the exact forms and procedures employed in completing the construction of the refrigerating apparatus, wherein the intermediate blank 10 may be considered as a piece of raw material. S-uflice it to say that, as fully considered in the Schaefer et a1. application, a system of cuts and bends must be formed, desirably using a lancing procedure for the cutting, followed by-a folding procedure which enlarges the cuts. These cuts of course must not extend across the passage or joint areas 12, 17, 25, 26, 27, etc; and desirably, even the bending is done remotely of the joint area 12, in order to avoid injury to that area.

Reference is now made to Figure 2 and 3, which show a preferred construction of the three-Way joint area 12 for the connection of a dryer 11 and particularly for a so-called cavity dryer with concentric inlet and outlet structures. One element of this joint construction 12- is provided by the terminal portion 25 of the condenser passage 16, which portion is shown as a horizontal, integral duct, constructed according to said Schaefer at all invention and forming the leg of a T-shaped threeway connection. The two arms 26, 27 of said T-shaped three-Way connection are vertically oriented, as clearly shown in Figure 3. They resemble the other integral passages in that they have a peculiar, cross sectional outline, best shown in Figure 2 at 26. Such outline is characteristically irregular, because of inherent features of the processes of forming the passages as integral parts of the sheet structure. For instance, in the case of a roll-forged and inflated sheet structure, as illustrated, I

the outline 26 tends to be basically polygonal but to have curved lateral lobes, projecting outwardly and coming to a point in the plane where the original pair of sheets were in contact with one another. The curvatures of such lobes cannot be expected to comply accurately 'with predetermined shapes.

Nevertheless it is necessary to make a smooth, threeway transition between the so configured passageways; and it is, moreover, necessary to form at least one of these. passageways, whether it be an arm or a leg of a T or. some other branch of the internal joint structure, iniform of a pair-of concentric passages, adequately sealed from one another.

The preferred manner of achieving such a seal-will become clear from consideration of Figure 3.

Here the two arms 26, 27 of the three-way connection 12 are formed as a straight passage, extending from a lower edge 28 of the sheet to an internal area adjacent to and surrounding the upper. end of a capillary restrictor passageway 17.. 1 The lower end of the arm 26, opening through the edge 28, has the neck 29 of a bulb-shaped cavity dryer 11 Connected and sealed thereto, for instance by a ring 30 of welding or brazing material joining the neck 29 to the edge 28 and internally retained by a steel sleeve 31. The restrictor 17 is formed by a tube, the outer diameter of which is small in comparison with the internal dimensions of the passage arms 26, 27 and sleeve 31; the tube being substantially coaxial with said passage arms and sleeve.

Before we consider further details of the concentric passage 17, 27, wemay note that a lower end portion 32 of the small tube 17 extends into the dryer 11, where it may be slidably held and centered by a small sleeve or center tube 33, desirably having a bottom intake portion 34 obliquely approaching the bottom 35 of the dryer bulb, while the sides of this center tube may be held to the inside wall 36 of the bulb by a pair of superposed spiders or so-called target members 37, 38. Suitable apertures 39 are. formed in both targets; and finemeshed screens 40, 41 are installed on said targets which are shown as flat perforated rings filling the area between the center tube 33 and theinside wall 36. The screens serve to remove foreign matter from the refrigerant and also to retain a body 42 of'silica gel or other desiccant or the like in the dryer bulb. The use of such material and the exact construction of the dryer bulb 11 are known to the art and form no object of the present invention, which: is concerned rather with the provision of effective and economical means for connecting such a bulb to the integral sheet and passageway structure 10 by a single external joint 30.

In addition to this external joint 30, we provide an internal seal 43, separating the passageways 25, 26 (normally a high pressure area). froman annular space 44, forming an outer part of the passage arm 27 (normally a low pressure area), while the wall of the restrictor 17 surrounds the capillary passage (normally an area of transition from high to low pressure). For this sealing effect it was found sufiicient and also preferable, if not necessary, to form the seal 43 as a body of lowtemperature soldering or brazing material, substantially retained during its hot and liquid condition, by a plug 45 snugly fitted upon the tube 17 and loosely fitted into the passage arm 27; it being understood that in the process of forming the seal, the sheet 10 is held upside down so that the liquid seal material 43 is at least largely supported by the plug 45. An excess of the material flows into the irregular lobes and other parts of the passage 27 surrounding the plug 45; it congeals incident to such flow.

A seal identical or similar to that shown'at 43 may be formed at the upper end of the passage arm 27. In that event the refrigerant dryer should be installed adjacent said upper end also.

The" internal seal is most effective when using aluminum, or alloys thereof, for each of the mutually contacting structures to be sealed, that is, for the sheet 10, the tube 17 and the solder body 43. It is also possible to form the capillary tube 17, in more conventional manner, as a copper tube; this, however, has the disadvantage that the provision of a strong and permanent bond then becomes more difiicult. The plug 45 is preferably formed of aluminum also; it can then be prejoined to the outer wall of the tube 17 by safe and simple procedures.

In aperation, refrigerant is pumped by the compressor 13 in directions shown by arrows in Figures 1 and 3; that is, first into the condenser 16; then horizontally through the condenser outlet 25; downwardly through the outer area of the passage 26 into the dryer 11, downwardly through the upper screen 40, dryer material 42 andlower screen 41; inwardly and upwardly through theintake '34, 1center tube 33, restrictor tube end 32 and restrictor tube 17; then into the evaporator 19 and finally downwardly back through the suction passage 22 and pipe 24 into the compressor. Any trace of humidity which may be present in the refrigerant material or passages, or may enter the same in operation, is removed by the dryer material 42. Also, any dust, mill scale, solder or flux particles or other solid impurities, which may enterthe' refrigerant, are removed by the screens 40, 41. No fluid flow occurs into or from the sealed passage space 44, which merely serves to separate the capillary tube 17 from the irregularly shaped passage walls 26 shown in Figure 2. In order to provide rapid heat exchange between passages 17 and 22, an elongated portion of the space 44 should be flattened, after insertion of the tube 17, so as to establish mechanical contact between the tube and the sheet metal walls.

While only a single embodiment of the invention has been described, it should be understood that the details thereof are not to be construed as limitative of the invention, except insofar as set forth in the following claims.

We claim: 2

1; In a refrigerant circuit structure comprising a unitary sheetwith a refrigerant passageway circuit therein and also comprising a refrigerant conditioner external to the sheet, the improvement which comprises a passageway section integrally formed in said sheet for connecting said circuit with said'conditioner, said section providing a pair of ducts separated from one another but forming parts of said'circuit, one of the ducts leading from one of the passageways within the sheet to an inlet of the external conditioner and the other leading from an outlet of the-external conditioner to another of the passageways withinthe sheet; and means within the sheet for sealing said passageways one from the other except insofar as they are interconnected by said ducts, said unitary sheet with said ducts therein, as well as said sealing means within'the sheet, substantially consisting of aluminum.

2. In a structure as described in claim 1, the feature that said ducts' are concentric, the duct leading from said outlet being innermost.

3. In a heat exchanger structure for refrigerating apparatus, incorporated in a unitary sheet with passageways formed therein and providing integral condenser, restrictor and evaporator means in refrigerant fiow circuit, combined with external refrigerant conditioner means, the' improvement which comprises a multiplebranch passageway section integrally formed in said sheet, said section having a first branch leading to an outside area of the sheet, a second branch leading to the condenser means, and a third branch leading to the evaporator means, said first branch being adapted to provide a pair of ducts separate from one another, one leading from'the second branch to an inlet of the con ditioner means and the other leading from an outlet of the conditioner means to the third branch; and means in said sheet for sealing the third branch from the first and second branches except for the last mentioned duct.

4. In a structure as described in claim 3, the feature that said first, second and third branches form a Tshaped passageway section.

5. In a structure as described in claim 4, the feature that said ducts provided by the first branch are concentric.

6. A structure as described in claim 5, additionally comprising a plug snugly fitted onto the innermost duct and loosely fitting into the third branch, the means for sealing the third branch comprising a body of seal material retained by said plug in the third branch adjacent the branch passageway section.

7. In refrigerating apparatus, a refrigerant conditioner such as a dryer having an outer wall with a unitary surface thereon and having ingress and egress openings closely associated with one another and extending through said surface; a unitary sheet structure external to said conditioner with evaporator and condenser passages therein, and, in circuit with said passages, a pair of conduits in said sheet structure, respectively and separately connecting said passages with said openings; and means on the outside of the unitary sheet structure for connecting said surface thereto, with said openings separately connected as described.

8. In apparatus as described in claim 7, the feature that the conditioner is a cavity dryer and that said conduits are concentric with one another.

Hintze L Feb. 11, 1941 Bottom Dec. 30, 1952

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