US2340780A - Refrigeration apparatus - Google Patents

Description

v. v. TORBENSEN 2,340,780

REFRIGERATION APPARATUS Filed May 26, 1941 3 Sheets-Sheet 1 H L Wm Q INVENTOR V/GGOKTORBENSEN BY W1C.

ATTORNEYS Feb. 1, 1944.

Feb, 1, 1944. v, v. TQRBENSEN 2,340,780

REFRIGERATION APPARATUS Filed May 26, 1941 s Shets-Sheet 2 m4 j 5/ a 39 V F I Y I 1 -"50 i I II J [B 1 -11 m] RIG 7 INVENTOR V/GGO M TORBENSEN BY flmv iwn ATTORNEYS Feb. 1, 1944. v. v. TORBENSEN REFRIGERATION APPARATUS Filed May 26 1941 3 Sheets-Sheet 3 F/Ql/ INVENTOR V1060 VERBEMSEN.

. ATTORNEY Patented Feb. 1, 1944 Application May 26, 1941, Serial No. 395,163

7 Claims.

The present invention pertains to improvements in refrigeration apparatus and methods of construction.

An object of the invention is to provide improved means for maintaining 'two temperature zones in a single refrigerator.

Another object is to provide improved apparatus of the above type embodying a mild temperature non-freezing compartment for ordinary food storage and a low temperature or deep-freezing compartment for storage of frosted foods, ice cubes and the like.

A further object is to provide a structure of the above type in which the temperature and humidity of each compartment are unaffected by those of the other.

Another object is to provide easy access to each compartment without affecting the other.

Another purpose is to provide an improved deep-freezing structure.

A further object is to provide a simplified deep freezing unit including a two-passage refrigerating tube coiled about and intimately joined to the walls of an inner receptacle.

Another object is to provide a unit adapted by counterflow of refrigerant through the two tubing passages to maintain an even temperature throughout the inner freezing surface.

Another object is to provide suitable methods for forming the twin-passage tube and for constructing the low temperature freezer embodying the same.

Another object is to provide an improved nonfreezing cooling coil for the mild temperature compartment.

A further object is to provide improved means in conjunction with the non-freezing coil for augmenting the humidity in the mild temperature zone.

A still further object is to provide a unitary structure including the above two different temperature devices and adapted to be readily installed as a unit in the body of the refrigerator.

Other objects and advantages of the invention will appear during the course of the following description, in connection with the accompanying drawings, in which- Figure 1 is a vertical sectional view of a refrigerator embodying the invention, the section being taken in the plane l-l, Figure' 2;

Figure 2 is a similar view taken in the 2-2, Figure 1;

Figure 3 is an enlarged detail cross section of the twin-passage tubing, illustrating a method of forming the latter;

plane sulated front door 22.

Figure 4 is an enlarged top view of the deepfreezing unit with surrounding material removed to illustrate the structure;

Figure 5 is a front view of the same partiallyin section on the lines 5-5, Figure 4;

Figure 6 is a detail sectional view of the closed end of the twin passage tube in the plane 6-6, Figure 7, showing a method of connecting the two passages;

Figure 7 is another sectional view of the same in the plane 1--'|, Figure 6;

Figure 8 is a detail section in'the plane 88, Figure 9, illustrating a means of affecting outside connections to the twin passages;

Figure 9 is another sectional view of the same in the plane 99, Figure 8;

Figure 10 is an enlarged front view of the nonfrosting cooling apparatus half in section;

Figure 11 is a plan view of the humidifying pan or grid;

Figure 12 is a plan view of the drain pan or id;

Figure 13 is a rear elevation showing an alternative form of the deep-freezing unit;

Figure 14 is a detail longitudinal section in the plane "-14, Figure 15, showing one type of end fitting for a common exterior connectionto both of the twin tube passages;

Figure 15 is a cross sectional view of the same in the plane |5'-l5, Figure 14;

Figure 16 is a fragmental detail elevation illustrating another method of providing for a common end connection to both of the twin passa es:

Figure 17 is an end sectional view in the plane l'l-ll, Figure 16, and

Figure 18 is a fragmental sectional view showing a detachablestandpipe applied to the drain grid.

Referring to Figures 1 and 2, the numeral 20 generally denotes a refrigerator cabinet having an outer shell 2| and equipped with an in- An inner shell. 23 xtends to a point above the door 22 to define a lower storage chamber 24, suitable heat insulating material 25 being provided between-the bottom, sides and back of inner shell 23- and the outer shell or casing 2|.

A pan 26, closely fitting in the upper portion of the outer casing 2|, engages the top of the inner shell 23. A low-temperature cooler or deep-freezer 21, illustrated as of rectangular shape and described in detail hereinafter, is disposed in the pan 26. A layer 28 of insulating material of substantial thickness is provided between the cooler 21 and the bottom of the pan 26,

and heavy insulation 28 also surrounds .the vertical walls of the freezer. A top plate 30, preferably secured to the open upper rim-of the freezer 21, engages the top of the refrigerator shell 2|.

An insulated lid 3| is attached by means of hinges 32 to the rear wall of the outer shell 2|, this lid forming the top of the refrigerator structure and normally serving as a main insulating closure for the compartment 33 of the deepfreezing unit 21.. One or more suitable sealing gaskets 34 may be provided between the lid 3| and the top plate 30, and the lower side and front edges of the lid may terminate in a bead 35 overlapping the upper edges of the outer casing 2|.

A non-frosting non-dehydrating cooler 31, hereinafter also described in detail, is suspended by means of strap brackets 31* from the bottom 36 of the pan 28,

It will be seen that the pan 26, its contained deep-freezer 21 and its depending lower cooler 31 comprise a unitary structure adapted to be bodily lowered into the main refrigerator casing 2|, the bottom of pan 26 becoming the top liner of the mild temperature chamber 24 and prop erly positioning the cooler 31 therein, while the insulating layer 28 in the pan provides a bar against heat leakage from chamber 24 to the deep-freezer compartment 33.

The deep-freezer 21 in preferred form is constructed as follows, referring first to Figures 4 and the inner lining walls 38 and bottom 39 of the compartment 33 are made of sheet metal.

A coil of tubing 40 is closely wound around the walls 38 and intimately joined thereto throughout, preferably by the well-known process termed stitch-welding, in which two flat surfaces are electro-welded together in a continuous band by means of a heavy current directed through them from suitable electrodes engaging the adjacent outer surfaces.

The tubing 48 is preferably of the shape illustrated, shown in enlarged cross section in Figure 3, which figure also illustrates a method of forming the tubing. In this method, a round or other conveniently shaped tube of suitable metal such as soft drawn steel. copper, or the like, isfed between two specially shaped rolls II and 42. The roll 42 flattens one side 43 of the tube to a substantial width while the double concave roller 4| depresses the middle of the opposite wall to form a central substantially fiat portion 44 which is pressed against the opposite fiat wall 43; at the same time the contours of the rolls form tubular side portions 45 and 45 defining twin passages 46 and 41. The central fiat portion 44 is then hermetically fused or welded to the wall 43 by the stitch-welding method mentioned above. The tubing may also be hot-rolled to the described shape, the welding then taking place during the rolling, after the manner of producing the welded seams in lap-welded steel pipe. The twin-passage tubing 40, formed as de Y scribed and having been annealed if necessary,

- on the size of unit.

rent and for sound and even welding; it will be obvious to those skilled in the art that this result would not be feasibly the case with ordinary tubing lacking the above provision.

Applicant is aware that cooling units are made by welding or otherwise joining together two sheet members, in one or both of, which channels have previously been pressed to form passageways between the members when joined. However, the application of this method with reasonable economy is limited to high production of a comparatively small number of shapes and models, due to the necessity of providing expensive dies for each model; the necessity for special dies also places a practical upper limit With applicants method, on the other hand, intimately welded cooling units may be cheaply produced in any desired quantities, large or small, and with no limitation as to size, special large dies not being required.

Furthermore, it is possible with the present invention to form the cooling coils with the adjacentwalls of successive turns abutting as in Figure 5, allowing a maximum length of passage thus forming a U-junction or opening 49 between the passages.

The lower ends of both passages 46 and 41 are pinched and welded shut as shown in Figure 8. Inlet and outlet fittings 50 and 5| are secured in sealing relation to the back of the tubing 40 by welding, brazing or the like. The outlet fitting 5| has an internal .opening' through a hole 53 from the passage 41 as shown in Figure 9, while the inlet fitting 50 is provided with a similar opening 52 into the passage 46. A pipe 54, se-

cured in or formed on the fitting 50, is adapted to be attached to an expansion valve 55, Figures 1 and 2. Similarly, a pipe 56 from the fitting 5| is provided for a suction connection.

In operation, when refrigerant is admitted through pipe 54 from the expansionvalve, it travels the entire length of the tubing 48 in the passage 46, through the U-connection 49, (Figure 6), thence back through the second passage 41 to the suction pipe 56. The structure thus causes evaporation in direct counterfiow relation between all adjacent passages throughout. the entire coil. The eifect of this complete counterfiow evaporation is to equalize or counterbalance any tendency toward an evaporating temperature gradient due to friction in the passages and to gravity, producing a substantially constant uniform temperature throughout the unit and thereby avoiding comparatively warm or cold zones such as occur in prior structures, for example in the usual type of ice-cream cabinets.

A further advantage of the described structure is that it locates the inlet and suction near together at one end of the coil, promoting simplicity, compactness, and requiring a minimum of exterior connecting tubing.

After the deep freezer has been constructed as described, it may be given a coating of corrosion-reslsting metal by hot-dipping or other suitable process; or if desired when metal of sufficiently high melting point has been used in construction, the interior of the freezer may be given a vitreous lining.

A removable partition 51 is provided in the deep-freezer 21, employed for-example in case one portion of the interior is to be used for storing ice cubes and the other for frozen foods. Sub-lids 58 and 59 having hinges 60 removably clipped to the partition 61, are adapted to protect each of the two sub-compartments of compartment 33 from heat entry while the other is open. The partition 51 and sub-lids 58 and 59 may be made of metal or of a suitable plastic sheet having low-heat conductivity.

Referring to Figures 1, 2 and 10, the mild temperature cooler 31 comprises a'coil of finned tubing 6| secured at the sides to the straps or brackets 31 by means of U-bolts 62. Small saddles 63, preferably of heat insulating material, are provided between the straps and the tubing to prevent crushing the fins 64, as shown in Figure 10.

The coil 6| is provided at its rear upper left comer with an expansion valve 65 of any suitable type, herein illustrated as of the thermostatic type having the usual 'feeler bulb 66 attached to the suction tube 61 of coil 6|, Figure 10. The suction line from coil 6| and the liquid tube 68 to the expansion valve 65 are led outward through a slot 69 in the rear wall of the refrigerator cabinet 29, a suitable union being provided in the suction line to facilitate installation as hereinafter set'forth.

The inlet pipe 54 and suction pipe 56 of the hind. the rear upper right comer of the cooler 31 as shown in Figures 1 and 2. The liquid line 1| of the valve 55 and the suction line 12 connecting to the pipe 56 are led out through the slot 69, the suction connection also being made through a union 13. The valve 55 may also be of the thermostatic type with the usual feeler bulb 55 clamped in thermal contact with the suction line 12. A detachable insulating shield may be provided about the low temperature expansion valve and suction connections as shown in Figure 2, to prevent any air dehydration due to frosting of these members.

other so that when in place they press firmly against the'strap ends 16, thereby preventing looseness and possible rattling.

The sides 19 have suitable openings or windows 83 (Figures 3 and 10), to allow and promote circulation of air through the cooler 31.

A humidifying receptacle 84 for water, preferably of grid form as shown in Figures 1, 2, l0 and 11, is slidably mounted on angles 85 secured to the inner sides of straps 31 above the coil 6|, and is removable through a slot 86 in the front plate 88. The humidifier grid comprises shallow longitudinal channels 81 connected at the ends by cross channels 88. Open slots 89 between the channels 81 are provided to allow free air circulation over the channels and downward through the grid. The channels have substantially vertical sides in order to provide practically constant evaporating surface area with varying depths of water therein.

' A lip 90 on the front of the grid receptacle 84 serves as a handle for removing the grid through the slot 86 and also facilitates refilling the receptacle with water.

Bolted to the inturned lower ends of the straps 31 is a drain grid 9|, shown in plan view in Figure 12, and comprising narrow longitudinal channels 92 connected by a narrow cross channel 93 at the front, and by a wide basin 94at the rear. The longitudinal channels 92 and front channel 93 underlie the longitudinal and front tubing portions of the coil 6|, being made with r I only sufflcient width to catch any drip from. the

The straps 31 are secured to the pan bottom I 36 by cap screws 14 passing through the outwardly turned upper ends 15 of the straps and screwed into blind spuds 16 permanently sealed to the pan bottom 36. The strap ends 15 are spaced away from the pan 36 by washers 11. A U-shaped one pieoe shield 18 comprising side plates 19 and a front plate 88, encloses the complete assembly of the cooler 31 and related parts.

The upper edges 8| of the sides 19 are turned inward to overlie the tips of the strap-ends 15 as shown in Figure 10, the ends 15 thus providing a means of retaining the shield 18 in place. Notches 82, Figure 2, in the edges 8| allow the shield 18 to be installed by raising it upward just inside the front wall of the refrigerator until the edges 8| pass the strap ends 15. then pushing the entire shield back into position as shown. Y

Obviously the shield may be removed by the reverse procedure without disturbing any of the other apparatus. The shield 18 is preferably formed with the sides 19 bent slightly toward each ,finned tubing and insuring free air passage through the large longitudinal openings 95. The rear basin 94 underlies the rear tubing portion of the coil 6| and also extends rearwardly, as shown in Figure 2, to catch any possible drip from the expansion valves 55 and and the suction connections.

The bottom of the grid 9| slopes downward throughout toward a drain hole 96 provided with a small downwardly extending spout 91 (Figure 2). The channels are preferably V- shaped in order to minimize the possibility of any splashing. The screw connections to the straps 31 are made through bosses98 extending upward from the bottom of the grid. and

the outer rim 99 of the grid is flared outward adjacent the bosses to catch any drip from the straps.

Both the humidifying receptacle orgrid 84 and the'drain grid 9| may. be made of stamped or die cast metal, or if desired may be made of suitable waterproof plastic material.

To catch the drip from the spout 91, a jar I09 or other suitable receptacle may be placed under the spout on a convenient shelf IN, or the jar maybe placed on the bottom of the compartment 24 with some types of shelf arrangements. Obviously,the compartment 24 may be equipped with any desired number and arrangement of shelves, only the shelf |0| being shown herein for purposes of illustration.

In assembling the refrigerator. the entire refrigerating structure, comprising the pan 26, the insulated deep-freezer 21 contained in the pan. the mild temperature cooler 31, and the expansion valves 55 and 65, may be Dre-assembled as a unit. The lid 3| having been opened, the unitary. sub-assembly may be lowered bodily into the casing from the top, after which the connections to the liquid and suction lines 68, 1|, 61 and 12, are made behind the cooler 31. as shown. ,Removal of the shield 18, as previously described, allows access to the various union connections from either side.

The slot 69 may be made sufliciently large to allow insertion of the liquid and suction line tubes with their respective union fittings already applied to them, these tubes preferably being placed in position before installation of the above described unitary sub-assembly. After installation, the slot 89 is suitably sealed against leakage of air and heat.

It will be understood that the suction and liquid lines 61, I2, 68 and H are exteriorly connected to any suitable type of refrigerating machine equipped with controls for operating the deep-freezer 21 and the cooler 31 at their different. proper temperatures, but as such machines and controls are well known in the art and form in themselves no part of the present invention. they are not shown herein.

The refrigerator 2!! may be provided with the usual bottom compartment I02 for the refrigerating machine, this compartment being made of minimum height to minimize the overall height of the cabinet/and allow easy access to the deep-freezer compartment 33.

The top plate 30. (Figures 1 and 2), is preferably secured in sealing relation to the upper edge of the pan 26, thus insuring complete protection for the insulation 28 and 29 at all times against entry of moisture. -Similarly, the insulating material 25 in the lower portion of the cabinet is sealed by a thin plate I03 secured to the outer shell 2| and inner shell 23 at the upper end of the latter.

In operation, the deep-freezer 2'! is normally operated to maintain the compartment 33 at a low temperature suitable for proper storage of frosted foods, ,pre-frozen ice cubes and the like; while the lower coil 6| maintains the compartment 24 at a mild temperature proper for ordinary food storage. Access to the deepfreezer compartment 33 is of course obtained by raising the lid 3|, an advantageous arrangement in itself since there is less tendency for escape of cold air upward during opening than in the case of sharp freezers opening horizontally.

The front door 22 provides access to the compartment 24 in the usual manner. The heavy insulation 28 in the pan 28 prevents the temperature of the two compartments from affecting each other as noted.

A drain I84 (Figures 4 and leads from the bottom of compartment 33 through. the pan bottom 36. The tube I05 Of drain i4 is preferably made of suitable plastic pipe such as Bakelite, having low heat conductivity, and is normally closed at the bottom by an insulating stopper or tacle placed on a shelf in compartment 24 below the drain tube. The draining of compartment 33 may be carried out during full normal refrigerating operation of the lower compartment 26, since the drip of cold water from the tube 1 05 can have no appreciable influence on the temperature or humidity'in the lower compartment. Similarly,

refrigeration of the lower compartment 24 may be discontinued for washing out or any other purpose without affecting the operation of the deepfreezer 21. c

The tubing GI and fins 64 0f the cooler 36 have an area sufilciently, great to allow proper cooling without coil temperatures low enough to cause frosting and consequent serious dehydration. Such water of condensation as occurs on the coil is partially restored to the air stream from the wetted surfaces and the drip downward through the coil, the excess being caught by the drain grid 9|. Meanwhile evaporation from the previously supplied water surface in the upper humidifying grid 84 augments the moisture supply of the air in the compartment. The form of the grid 84 and its location as shown, where its large water surface is swept by the warmest air in the compartment moving inward and downward toward the coil 6|, causes the grid to operate with maximum effectiveness to maintain a properly high balance of humidity, at the same time maintaining simplicity and making unnecessary the use of cumbersome and often ineffective devices such as forced humidifiers including fans and the like.

The grid forms Of both the receptacle 84 and the drain member 9| permit these devices to perform their functions with minimum interference with air circulation, in contrast to the serious interference caused by the large solid drip pans used in ordinary practice.

From the foregoing description, it will be evident that while the refrigerating apparatus for both temperatures comprises a unitary sub-assembly readily installed in orremovable bodily from the main cabinet shell 2|, the structure provides for completely independent operation of the two zones, neither being affected by the normal operation, opening and closing, or even discontinuance of operation of the other. these qualities make possible more convenient and economical operation than can be achieved by prior structures wherein both temperature zones are located in a single compartment or served by a single main door, often with little or no effective insulation between the zones; and with consequent requirement for frequent defrostings; furthermore, as previously noted, the unitary refrigerating structure described provides for economical manufacture and easy assembly.

It will be observed that the deep freezer com-' partment 33 is of large capacity and easily accessible throughout. This large compartment is especially adapted for keeping frozen foods and economical storage of pre-frozen ice cubes, but it is obvious that it may also be employed for freezing ice cubes by simply placing the necessary trays of water therein.

While the counterflow arrangement of the twin-tubing 40 as described is preferred, for some purposes it maybe desired to employ the general method set forth to construct coolers in which circulation of refrigerant takes place in parallel through the twin passages 46 and 41, such a cooler being shown in Figure 13. For this purpose, endfittings III! of the type shown in detail in Figures 14 and 15 maybe welded, brazed or otherwise secured to the ends of the tubing. Referring,

to Figure 14, the fitting I 01 has a single exterior connecting opening I08 and a common exterior passage I09 opening into both passages 48 and 41.

Another method of providing for a common connection to both passages is illustrated in Fig- ,Qures' 16 and 17, wherein the rolled and welded .zone 44 is terminated, as previously noted, at any desired distance from the end of the tubing stock, thus leaving the unrolled portion H0 round to Obviously permit attachment of the usual flared tubing unions or the like. The fittings I01, 50 and BI are illustrative, as obviously a variety of types and forms of fittings such as Ts, U-bends, etc., may similarly be provided for any desired exterior connections to the twin-passage tubing.

Referring again to themeans described for maintaining proper humidity in the lower nonfreezing compartment 24, it will be obvious that in the case of large refrigerators two or more humidifying grids 84 may be used if-desired. It may also be desired in some cases to provide a humidifying surfacebelow as well as above the non-frosting coil 6|. A convenient means of maintaining this surface is illustrated in Figure 18. A small stand-pipe H2, illustrated as made of rubber, is detachably inserted in the drain hole 98 of the lower grid 9|, the upper end of the pipe being a short distance below the top level of the rim 9|.

Water dripping from the coil 6| accumulates in the grid 9| until its level H3 reaches the top of the standpipe H2, after which any excess overflows through the pipe and out through the spout 91. The grid may be initially filled with water to the top of the standpipe, the level thereafter being maintained by drip from the coilas set forth.

While the throughout in preferred form, it is not limited to the precise structures and procedures set forth, as various modifications may be made without departing from the scope of pended claims.

What is claimed is: 1. In a refrigerator structure, in combination, a casing, an inner shell disposed in said casing the anand defining a lower chamber therein, an insulating wall between said casing and the side and rear walls and bottom of said shell, a pan disposed in said casing above said shell, the bottom of said pan comprising the top closure of said lower chamber, an evaporator structure attached to the bottom of said pan and depending there from in said lower chamber,-said evaporator being adapted to provide amild temperature in said lower chamber, a second evaporator structure in said pan and including an upwardly opening sharp freezing chamber, a body of insulating material of substantial thickness forming an effective heat bar between the inner surfaces of said pan and the sides and bottom of said freezing invention has been described chamber, an insulated lid on said casing, saidlid normally comprising a top closure for said sharp freezing chamber, and a front door on said cas me, said door normally comprising the front closure for said-lower chamber.

second evaporator structures comprise a unitary structure removable upward bodily from said casing.

3. A structure as claimed in claim 1 including means forming a drain from said freezing chamber into said lower chamber, and means operable in said lower chamber to close and open said drain.

4. A structure as claimed in claim 1 including regulating means connected to said first evaporatorstructure and adapted to regulate operation thereof above the freezing point of water, and regulating means connected to said second evaporator structure and adapted to regulate operation thereof below thefreezing point of water, both said regulating means being comprised in said lower chamber. I

5. In a refrigerator structure, in combination, a cabinet including a lower chamber, means including an evaporator and forming a sharp freezing chamber in the upper portion of said cabinet, a second evaporator in said lower chamber and adapted to maintain a mild temperature therein, means in said lower chamber to independently regulate said respective evaporators to produce 'a sharp freezing temperature in said upper chamber and said mild temperature in said lower chamber, and means forming a common insulating wall between said chambers to substantially prevent inter-dependence of said temperatures,

said two evaporators and said wall comprising a unitary structure removablebodily from said cabinet.

6. In a refrigerator structure, in combination,

a cabinet, a sharp freezer in the upper portion of said cabinet, a lid on the top of said cabinet and normally forming a closure for said sharp freezer, a mild temperature cooler in said cabinet below said sharp freezer, means to individually control the temperatures of said sharp freezer and said mild temperature cooler, walls of insu lation in the top, the four sides and the bottom of said cabinet, saidinsulation being thicker' about the top and the side walls of said sharp freezer than the thickness of the walls about said mild temperature cooler, and common insulating means between said sharp freezer and said mild temperature cooler to prevent interdependence of said temperatures.

7. The structureaccording to claim 6,. including -VIGGO V. TORBENSEN.

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