US2065542A - Refrigerating apparatus - Google Patents

Description

295 1936- H. F. SMITH 2,065,542 REFRIEEERATING APPARATUS Original Filed Nov. 24, 1950 2 Sheets-Sheet 1 j :I j m IIJIIIIIIIIIIIIIIIIII:IIIIIIIIIIIIIIIIIIIIILIIII.-..I..L'

INVENTOR BY g ATTORNEYS 1936. H. F. SMITH REFRIGERATING APPARATUS 2 Sheefs-Sheet 2 Original Filed Nov. 24, 1950 INVEIlTgOR MMV% ATTORNEYS Patented Dec, 29, 1936 UNITED STATES PATEN OFFICE BEFRIGERATING APPARATUS I Harry F. Smith, Dayton, Ohio, assignor, by mesne assignments, to General Motors Corporation, a corporation of Delaware Application November 24, 1930, Serial No. 497,704

Renewed August 23, 1934 f is to provide an improved evaporator structure and more particularly toprovide an improved evaporator structure wherein the liquid refrigerant is caused to pass over an increased refrigerating surface by forces generated within the evaporator.

A further object of this invention is to provide an improved evaporator construction employing a liquid refrigerant reservoir wherein means are provided for lifting the liquid refrigerant to a refrigerating surface above the lev of liquid in the reservoir.

A still further object is to provide an evaporator for use in absorption machines, said evaporator being so constructed and arranged that its refrigerating surfaces are at all times contacted by cold liquid refrigerant and wherein means are provided for preventing the transfer of hot refrigerant into contact with the refrigcrating surfaces.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a sectional view on the line l--l of Fig. 2 of a cooling unit embodying the invention together with a diagrammatic illustration of the remaining elements-in an absorption refrigerating system;

Fig. 2 is a section on the line 22 of Fig. 1;

Fig. 3 is a fragmentary sectional view of the double wall of the cooling unit;

Fig. 4 is a sectional view of a modified form of applicant's invention; and

Fig. 5 is a section along the line 5-5 of Fig. 4 with a portion broken away.

In Fig. 1, for illustrative purposes, is shown refrigerating surfaces during the generating 'designated by the reference character 3|.

ed by the burner l5, controlled by a valve I6 and provided with a pilot light I4, and then cooled by a cooling coil I1, controlled by a valve l8. During the heating of the generator-absorber the ammonia vapor is driven through the conduit II to the condenser l2 where it is liquelied and fiows through the conduit l9 intothe supply reservoir 20 of the evaporator l3, while during the cooling of the generator-absorber, some of the liquefied refrigerant is drawn in vapor form from the evaporator and absorbed by the generator-absorber l0.

fluctuating level of refrigerant decreases the efllciency of the apparatus since hot gaseous and liquid refrigerant is brought in contact with the period. 1 To overcome these disadvantagesl so construct my improved evaporator that the refrigerating surfaces thereof are at all times, both during the absorption and generating cycles, in contact with relatively cold liquid refrigerant. This is accomplished in my improved construction by stopping the absorption period and starting the heating or generating cycle while a considerable quantity of liquid refrigerant still remains in the evaporator. This is also accomplished by utilizing forces generated within the evaporator itself for forcing the liquid refrigerant onto the refrigerating surfaces, these forces being generated only during the absorption period. In the preferred embodiment of the evaporato l3 there is shown a supply reservoir 20 which is positioned between the sides of a U-shaped plate type heat absorbing member 2|, as is more clearly shown in Fig. 2. This heat absorbing member is formed of two sheets or plates of metal,the outer sheet being designated by the reference charter (see Fig. 3) .and the inner sheet being These sheets are made of stainless steel and have a plurality of impervious cup-shaped depressions 32 therein. The outer sheet 30 has depressions with corresponding projections of greater depth 55 than those of the sheet 3| so that the projections of the outer plate, which extend inwardly, will nest into the depressions in the inner sheet 3| and leave a narrow refrigerant; space between the two walls. The most convenient form of these depressions is a cup-shape with a fiat bottom. If desired, however, other shapes may be used. These two members provide the means for cooling the refrigerating compartment which it is desired to cool.

This type of wall structure has a number of advantages over the older types of wall structure. One of these advantages is the fact that with this structure a much narrower refrigerant space can be obtained and thus a lesser amount of refrigerant is required to fill the refrigerant walls and consequently a lemer amount of refrigerant is required to charge the system.

Another disadvantage is the fact that in weldmg no distortion of the sheets will take place. When using sheet materials having a 'high strength at relatively high temperatures this becomes a very important advantage. This is especially true when stainless steel is used. When welding the nested cup-shaped projections and depressions of applicants wall to hold the sheets 30 and 3| of applicants refrigerant wall in spaced relation, the expansion caused by the heat of welding is absorbed by a slight distortion of the cup-shaped projections and for this reason the wall structure itself is not distorted.

Another advantage of this structure is that the nested construction facilitates the welding operation since it holds the sheets together in proper relation during the welding operation and prevents them from slipping. Upon the completion of the welding operation the nested construction will oppose any forces in the plane of the wall tending to move one sheet with respect to the other.

According to the present invention the space between the two walls is kept filled with liquid refrigerant in a novel manner by a novel structure which includes a vapor lift device. Supported upon the lower part of the walls of the U-shaped heat absorbing member 2| and beneath the supply reservoir 20 is a shelf 35 for supporting an ice tray 36. A second ice tray 49 is supported on the bottom of the member 2| directly beneath the shelf 35. This shelf is of a construction similar to the wall 2| shown in Fig. 3, so as to contain liquid refrigerant for cooling the ice tray 36 which it supports. This tray supporting shelf is supplied with liquid refrigerant from the supply reservoir or tank member 20 by means of a conduit 31 which extends downwardly from the reservoir to a point below the shelf and then makes a reverse turn, which forms a trap portion and finally enters the shelf 35 from the bottom as shown at 38. At the side of the shelf 35, a duct 40 enters directly upwardly into a distributing member 4| located at one side of the evaporator near one of the walls 2|. either side of the distributing member 4| conduits 42 extend horizontally and are connected to the U-shaped member for keeping this heat absorbing member filled with liquid refrigerant. Gaseous refrigerant is withdrawn from the distributing member and conducted to the supply reservoir 20 through an L-shaped conduit 43.

The supply reservoir 20 and distributing member 4| and connecting conduits 42 are surrounded with an insulation of granulated cork 44 which is enclosed at the top and bottom by sheet metal members 45 and 46 and at the front and rear by sheet metal members 48 and 41. This insulation is made necessary because of the fact that during the generating period hot gases fiow into the supply reservoir 20 and the heat from these hot gases must be prevented from reaching the compartment to be cooled.

The level of liquid refrigerant which is supplied to the reservoir 20 through a conduit 29 fluctuates because of the intermittent operation of the absorbing refrigerating system. For in- I stance, at the end of the absorption cycle the level of liquid refrigerant within the supply reservoir is lowered approximately to a point designated by the reference character 5|. The re frigerant in my improved evaporator is kept in contact at all times with the refrigerant surfaces regardless of the fluctuation of the level of liquid refrigerant within the supply reservoir of the evaporator by a vapor lift. The liquid refrigerant in the cooling unit naturally seeks its own level and fills the duct 31, the passageways in the shelf 35, and the lower part of the duct 40. The heat given off by the ice trays 36 and 49 causes the boiling of the portion of the liquid refrigerant within the shelf 35, and since the duct 3! has a trap portion therein and is connected to the bottom of the shelf, the evaporated gaseous refrigerant cannot return through the duct 31 but must ascend up the duct 40 and will carry liquid refrigerant along with it, after the manner of an air lift pump, into the distributing member 4|, from which point the liquid refrigerant will flow through the connecting conduits 42 to the walls of the heat absorbing member 2|, while the gaseous refrigerant will pass out of the dis-.

tributing member through the L-shaped conduit 43 into the supply reservoir 20.

It has been found that there is sufficient heat absorbed from various other sources to produce enoughboiling to keep the heat absorbing member substantially filled even when the ice trays have not been in use for a considerable length of time. From this it will be seen that an evaporator has been provided with refrigerating surfaces which at all times are in contact with the cold liquid refrigerant. Thus during the heating or generating period refrigerant cannot contact with these surfaces.

In ,the modification shown in Figs. 4 and 5 the invention is shown advantageously applied to an evaporator for an ice cream cabinet. Heretofore it has been difllcult to secure'proper cooling at the top portion of the brine tank in an ice cream cabinet of this type as well as to secure proper circulation of the brine within the tank. Consequently the top of theice cream within the container becomes softer than desired. My principle of invention including the vapor lift has been applied to this situation and solves this problem by placing the major heat absorbing portion above the supply reservoir of the cooling unit. This also improves circulation of the brine within the brine tank since the cold brine'will move to the bottom of the-tank to be warmed there and will then rise to the top of the brine where it will again be cooled by the evaporator.

In my improved construction a large aperture I00 is provided within the wall "II of the brine tank. The cooling unit I2 is fastened to the closure plate I03 of the aperture I00 and is removable with this closure plate. A supply reservoir I04 which has its front end fitting within an aperture within the closure plate I03, projects rearwardly therefrom into the brine and is surrounded by suitable insulatlon such as granulated cork I05 which is enclosed within a metal shield I06. Supported on top of the shield I06 is a heat absorbing container I'I consisting of a pair of refrigerant ducts I08 and I09 having a cross section somewhat similar to a key-hole. These ducts are connected at the front end by cross ducts H0 and are provided with fins I I I to increase the area of heat transfer between these ducts and the brine in the top portion of the tank. The tank should be filled with a sufficient amount of brine in the tank so as to cover'the tops of the fins.

lower portion of the brine tank. The duct H2 is closed by plug H3 at its lower end. From the lower portion of the duct II2 a pair of smaller ducts III and II5 extend upwardly to connect into the refrigerant duct I09 of the heat absorbing member. These ducts III and M5 are provided with a plurality of fins IIII and III for causing a relatively large amount of heat to be absorbed from the brine tank at this point.

As in the first described embodiment liquid refrigerant partially fills the supply reservoir Iill, the duct H2, and the duct H5. Heat absorbed from the brine by the fins lit and I II causes the liquid refrigerant in the conduit I I5 at this point to boil and pass upwardly carrying liquid refrigerant up into the refrigerant duct I09 of the heat absorbing container IIII. Liquid and gaseous refrigerant passes from the duct I09 to the duct I08 through the cross duct lit. The heat absorbed by the heat absorbing member IM vaporizes the liquid refrigerant within the ducts I68 and its and this vaporized refrigerant is'withdrawn from the heat absorbing member through the duct lib into the supply reservoir I00.

While the form of embodiment of the present 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. In an evaporator for refrigerating apparatus, the combination with a liquid supply reservoir adapted to contain liquid refrigerant, of a liquid refrigerant container having at least a portion disposed at a higher level than the reservoir and acontinuously open vapor lift disposed below the plane of the liquid refrigerant supply reservoir for conveying liquid refrigerant from the reservoir to said container, said container being separated from said reservoir but having means tus, the combination with a liquid supply reservoir adapted to contain liquid refrigerant, of a liquid refrigerant container having at least a portion disposed at a higher level than the reservoir, said container being separated from said reservoir but having means communicating with the reservoir above the level of liquid in the container and the reservoir, said container having surfaces exposed to an ambient fluid to be cooled, and a vapor lift responsive to temperature for conveying liquid refrigerant from the reservoir'to said container,

a support for an ice tray, said support being in intimate thermalcontact with saidvapor lift.

3. In an evaporatorfor refrigerating apparatus, the combination with a supply reservoir containing a quantity ,of liquid refrigerant and having a gas space, of a liquid refrigerant container having at least a portion disposed at a higher level than the reservoir. said container being separated from said reservoir but having means communicating with the reservoir above. the level of liquid in the container and the reservoir, said container having surfaces exposed to an ambient fluid to be cooled, a continuously open vapor lift disposed below the plane of the liquid refrigerant supply reservoir for conveying liquid, refrigerant from the reservoir to the container, and means for conveying gaseous refrigerant from the container to said reservoir.

4. In refrigerating apparatus, a cooling unit adapted to contain liquid and gaseous refrigerant, including a reservoir portion, a heat absorbing member adapted to contain liquid refrigerant, said heat absorbing member being separated from the reservoir portion but having a connection with the reservoir portion above the liquid level for returning evaporated refrigerant from the reservoir, and continuously open vapor to contain liquid refrigerant supplied from the reservoir, a second heat absorbing member separate from the supply reservoir and the first named heat absorbing member having at least a portion above the first-named heat absorbing member and said supply reservoir, a duct connecting the first-named heat absorbing member and the upper portion of the second heat absorbingmember, and a continuously open vapor lift means disposed below the plane of the liquid refrigerant supply reservoir and dependent upon forces generated in the coolingunit for carrying liquidrefrigerant through said duct from the first-namedheat absorbing member to the upper portion of the second heat absorbing member.

an cooling unit including a supply reservoir reservoir, said plate type refrigerating surface beng separate from said reservoir and being exposed to the ambient air, anda continuously open vapor lift means disposed below the plane of the liquid refrigerant supply reservoir and dependent upon forces generated within the cooling unit for keeping the plate type refrigerating surfacein contact with liquid refrigerant at all times. 1

7. A cooling unit including a brine tank adapted to contain brine up to a certain level, a reservoir for liquid refrigerant positioned within said brinetank, means for maintaining the reservoir partially filled with liquid refrigerant, a heat absorbing member separate from the reservoir and positioned above the normal level of the liquid h refrigerant within the reservoir but below the top of the brine, and vapor lift means for carryingliquid refrigerant from the reservoir to the heat absorbing member. I

8. In refrigerating apparatus a-cooling unit of the flooded type having separate box cooling surfaces and ice freezing surfaces, said box cooling surfaces having at least a portion above the ice freezing surfaces, means for maintaining liquid refrigerant in contact with said ice freezing surfaces, and vapor lift means dependent upon the ice freezing surfaces for forcing liquid refrigerant into contact with said box cooling surfaces.

9. In a cooling unit of the flooded type having separate ice freezing and air cooling surfaces, said air cooling surfaces having at least a portion above the ice freezing surfaces, means for maintaining liquid refrigerant in contact with the ice freezing surfaces, vapor lift means for supplying the air cooling surfaces with liquid refrigerant from the ice freezing surfaces, and a trap for preventing the flow of refrigerant from the air cooling surfaces to the ice freezing surfaces.

10. A cooling unit including a supply reservoir adapted to contain liquid refrigerant, a pair of opposed plate type refrigerating surfaces, at manifold for feeding liquid refrigerant to both refrigerating surfaces, means for supplying liquid refrigerant from the supply reservoir to the manifold, and means for returning refrigerant gas and the overflow of liquid refrigerant from the manifold to the supply reservoir.

11. An evaporator of the flooded type including a supply reservoir and separate ice freezing and air cooling members, said air cooling member having at least a portion located above the supply reservoin'said air cooling member being adapted to contain liquid refrigerant to a level above the supply reservoir, means for first conducting liquid refrigerant from the supply reservoir to the ice freezing member, and vapor lift means for conducting liquid refrigerant from the ice freezing member to the air cooling member, and for maintaining the level of the liquid refrigerant in the air cooling member above the level of liquid refrigerant in the supply reservoir.

12. A cooling unit including a pair of opposed plate-type refrigerating surfaces, amanifold for feeding liquid refrigerant to both refrigerating surfacesa supply reservoir below said manifold and vapor lift means for supplying liquid refrigerant from the supply reservoir to the manifold.

13. A cooling unit including a U-shaped platetype refrigerating surface, a supply reservoir containing liquid refrigerant positioned between the sides and below the upper portion of the refrigerating surface, and vapor lift means for supplying liquid refrigerant to the refrigerating surface above the liquid level in the supply reservoir from the supply reservoir.

14. A cooling unit adapted to be submerged in a heat transfer liquid maintained at a certain level, a reservoir for liquid refrigerant submerged within said liquid, means for maintaining said reservoir partially filled with liquid refrigerant, a heat absorbing member separate from and located above said reservoir, said heat absorbing member being submerged within the heat transfer liquid just below the surface thereof, said heat absorbing member being adapted to contain liquid refrigerant to a certain level, means connecting said heat absorbing member and said reservoir above the liquid level, for returning gaseous refrigerant to the reservoir, and vapor lift means for carrying liquid refrigerant from the reservoir to the heat absorbing member for maintaining the heat absorbing member supplied with liquid refrigerant.

15. A cooling unit including a supply reservoir adapted to be partially filled with liquid refrigerant, an enclosed refrigerant container separate from said reservoir and located above said reservoir, said container being the main heat absorbing member of the cooling unit, a continuously open vapor lift means disposed below the plane of the liquid refrigerant supply reservoir and connecting said supply reservoir and said container for supplying liquid refrigerant to said container, and a vapor and overflow conduit connecting the upper portion of said container and said reservoir for returning excess liquid refrigerant and vapor from the container to the reservoir.

16. A cooling unit including a brine tank adapted to contain brine up to a certain level, a reservoir for liquid refrigerant positioned within said brine tank, means for maintaining the reservoir partially filled with liquid refrigerant, a heat absorbing member positioned above the normal level of the liquid refrigerant within the reservoir but below the top of the brine, a looped duct depending from the reservoir and connecting the reservoir and the heat absorbing member, and means connected to the looped duct for raising liquid refrigerant to the heat absorbing member by the evaporation of liquid refrigerant.

17. A cooling unit including a reservoir portion partially filled with liquid refrigerant, a heat absorbing member below the reservoir portion, a second heat absorbing member having a portion extending above the normal liquid level of the refrigerant within the reservoir, said second heat absorbing member being separate from the reservoir, means for supplying liquid refrigerant to the first named heat absorbing member from the reservoir portion, and a continuously open vapor lift means disposed below the plane of said reservoir for carrying liquid refrigerant from the first named heat absorbing member to the upper part of the second heat absorbing member.

18. A cooling unit including a reservoir, means for keeping the reservoir partially filled with liquid refrigerant, a heat absorbing member having at least a portion extending above the normal liquid level in the reservoir, said heat absorbing member being adapted to contain liquid refrigerant, a distributing member positioned above the normal level of liquid in the reservoir, means for connecting the distributing member with the reservoir and the heat absorbing member for maintaining the distributing member filled with liquid refrigerant and means for raising liquid refrigerant from the reservoir member to the distributing member.

19. A cooling unit including a supply reservoir adapted to contain liquid refrigerant, an individually formed ice tray shelf beneath said supply reservoir for supporting an ice tray, said ice tray shelf having refrigerant passages therein, a pair of vertical opposed plate type refrigerating surfaces, one on either side of the ice tray shelf, a tubular member connecting said surfaces, conduit means connecting said reservoir and said ice tray shelf for supplying liquid refrigerant to said refrigerant passages in said ice tray shelf, conduit means connecting said ice tray shelf andsaid tubular member, and a trap in one of said conduit means for controlling the flow of liquid refrigerant.

20. In an evaporator for refrigerating apparatus, the combination with a supply reservoir adapted to contain liquid refrigerant, of a liquid refrigerant container separated from said reservoir and having'at least a portion thereof disposed at a higher level than the reservoir, said enema-a liquid refrigerant container being exposed to an ambient fluid to be cooled, a refrigerated ice tray support disposed below said reservoir and having a connection therewith and a connection with the liquid refrigerant container above the reservoir, and said refrigerated tray support being arranged to convey liquid refrigerant from said reservoir and to cause circulation of the liquid refrigerant to said container at a point above the supply reservoir.

21. In an evaporator for refrigerating apparatus, the combination with a supply reservoir adapted to contain liquid refrigerant, of a liquid refrigerant container separated from said reservoir and having at least a portion thereof disposed at a higher level than the reservoir, and means disposed below said reservoir for conveying liquid refrigerant therefrom and for causing circulation of the liquid refrigerant to said container at a point above the supply reservoir, said means being in the form' of a horizontally disposed refrigerated shelf for supporting a receptacle adapted to contain a substance to be congealed or frozen.

22. An evaporator for a refrigerating system including superimposed sheet metal portions having certain parts thereof secured together and certain other parts thereof spaced apart to form passages therebetween and providing a refrigerated wall arranged to cool air adapted to flow thereover, a refrigerated shelf separate from said air cooling wall and disposed intermediate the top and bottom of the wall for supporting a receptacle adapted to contain a substance to be congealed or frozen, means located above said shelf for supplying liquid refrigerant thereto, a conduit for conveying refrigerant from said freezing shelf to the air cooling wall of the evaporator, and said shelf and said conduit being arranged to cause liquid refrigerant to be elevated above the shelf and to be discharged into the air cooling wall of the evaporator at apoint above said liquid refrigerant supply means.

HARRY F. SMITH.

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