US1460677A - Air-refrigerating machine - Google Patents

Description

1.460.677 l. LUNDGAARD AIR REFRIGERATING MACHINE Filed May 22. 1922 3 SheetsfSheet l July 3, 1923.

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IN1/MOR Sheets-Sheet 2 i. LUNDGAARD AIR REFRIGERATING MACHINE Filed May 22. 1922 AM ...HHH 1 `Fully 3, 1923'.

Jul'y "3, 1.923.

Filed May 22,

1922 3 Sheets-Sheet 5 IHIHIW duly 3,. i923,

intornfl'f LUNDGABD, OF HARTFORD, CONNECTICUT, SSIGNOR TO THE AUTOMATIC BE- iS'R-EGERATJLNG COMPANY, OF HARTFORD, CONNECTICUT, A CORPORATION OF NEW IBI-REFRGERTING MACHTNEL .application led Eay 22, 1922. Serial No. 562,907.

v o @ZZ whom may cow/cam:

e it known that l, lvAR LUNDGAARD, a

citizen of the United States, and a resident "the air is expanded. Between these two chambers the .air is passed through a heat exchanger for transferring heat from the compressed air to a body of cooling fluid, a regenerator for maintaining a difference of i temperature between the air entering it and the air leaving it and a heat exchanger for transferring heat from a fluid to be cooled to the expanded air` Tn my Patent No. LFE-0,862 l have described a machine of this as the volume of the air spaces in the heat er1-changers and regenerator is constant and as this volume is interposed between the compression and expansion chambers, it comprises what might be considered a clearance volume and it is obvious that to obtain any great amount of refrigeration this volurn-e must be small as compared to the piston displacement. Further a large area mnst be presented to the air to transfer the heat to or from it. y

Since the function of the regenerator is to bring the mediating air to a temperature as nearly as possible equal to that in the chamber it is entering, whether it be the reiatively hot compression chamber or. rela- 11vely cold expansion chamber, it is necesary that it have capacityto absorb a given mount of heat during part of each cycle to given u at another part of the cycle. i order t at the outputof refrigeration be high, the regenerator must be constructed to prevent, as far as is possible, the ccnduction of heat from its hot end to its cold end. 7The object of my present invention is to produce a regenerator that will contain a' small volume of air, that' will present a large surface to the air, that will be easy' and 1 v cheap to manufacture, that will have suffi;I

.sections extendacross the path of low of cient heat capacity to maintain its hot end and its cold end at the proper relative temperatures, that will conduct the minimum amount of heat from its hot end to its cold end, and that will offer low resistance to the passage of air.

I accomplish this object by constructing my regenerator in the form of a chamber, the walls of which are composed of heat insulating material, and providing in the chamber a plurality of sections of material having the required heat capacity, and eX* tended surface, and a multiplicity of narrow spaces for the passage of air. -These the mediating fluid and are separated from each -other so as not to be in heat-conductive relation. Each section may, for example, consist of a plurality of turns of thin metallic ribbons closely spaced with respect to each other and mounted so that their edges are presented in the direction of ow ofthe mediating fluid.

n order that my invention may be clearly understood, it will be described in connection with the accompanying drawings, and the novel features will be pointed out inthe annexed claims. In said dravvinA Figure 1 is a vertical, longitudlnal section of my airJ refrigerating machine, of` which regenerators according to this invention form a part.

Figure 2 is a vertical, transverse section on an venlarged scale of one of the regenerators shown in Figure 1.

Figure 3 is a bottom generator of Figure 2.

Figure 4 is a vertical, transverse section of another embodiment of my invention.

Figure 5 is a bottom plan view of the regenerator of Figure 4 showing in part the plan view of the remetallic strips forming the heat storage elements. Referring to Figure 1, the operation of the machine may be as follows for one cycle of operations, which corresponds to one revolution of the crank-shaft. The move` ments of the pistons are controlled by the mechanism in the crank-case.

The air is compressed in the chamberbetween compression piston 1 and shifter pis-4 ton 2 by upward movement yof piston 1. It is then transferred at the higher pressure through annular port 3, the spacesbetween leaves 4: of heat exchanger 5, the regenerator no their upper ends heat i temperature at all Y between turns being 6 and the spaces between leaves 7 .ot heat exchanger 8 to the chamber above shifter piston 2. lt is then expanded in the chamber above piston 2 by downward movement of both piston l and piston 2. Finally it is transferred back again at the lower pressure to the chamber between piston l and piston f2 through heat exchanger 8, regenerator 6 and heat exchanger 5. In this way, heat is discharged from the system by heat eX- changer 5 and heat may be abstracted from any desired fluid by heat exchanger 8. A difference of temperature is established between the two heat exchangers and consequently between the upper and lower ends of regenerator 6.

The machine illustrated in Figure l has two cylinders and it will be understood that both cylinders are similarly constructed.

Regenerator' 6 compri-ses an inner cylindrical wall 9 of heat-insulating material, such as bakelite and an outer cylindrical wall 10 also of heat-insulating material. An annular space is formed between the two walls. falls 9 and l() rest at their lower ends on the heat exchanger 5 and support at exchanger 8. Wall 9 serves also as a portion of the cylinder wall inside of which piston 2 reciprocates. lt is thus seen that the regenerator acts to insulate the hot end of the machine from the cold end while at the same time acting as a regenerator for the mediating fluid.

ln Figures 2 and 3, one embodiment of my invention is shown as consisting of a plurality of thin metal ribbons ll, wound spirally on wall 9, each turn being immediately over another but separated therefrom by narrow spacers 12, of insulating material, such as paper. Spacers l2 are arranged about the circumference at intervals, sutilciently close to keep the strips in position, and extend the full length of the regenerator. Each of the metallic ribbons 1l comprises a coil of several wraps around cylinder and each coil is separated, in the direction of flow of the mediating air, from the adjacent coils so to be heat-insulated therefrom, As any one coil is at approximately the same points, it is important to subdivide the length of the regenerator into as many coils and insulating spaces as will produce a relatively smooth temperature gradient between the two ends. ln regenerators I have constructed, which have given excellent results, there have been nineteen coils each having thirty turns ot brass ribbcn one-eighth of an inch wide by twothousandths of an inch thick` the spacers paper one-sixteenth of an inch wide by six-t ousandths fil :in inch thick. and the length-wise separation of the coils being eight-thousandths of an inch.

The outside diameter ot the coils of strips 1l is Such that outer. cylinder l0 will :ur-tedere' just slip over them. As the mediating air passes back and forth through the narrow spaces between turns it readily gives up or absorbs heat from the strips, while at the same time there is a small volume of air contained in the regenerator and a minimum of length-wise conduction or heat.

ln Figures l and 5, l illustrate another embodiment of my invention. The thin metal strips 1l are wound spirally about the cylinder 9 and each turn is spaced Yfrom the previous turn by corrugated metallic strips 18, the corrugations of which extend in the direction of iow of the mediating air. Therefore. each coil consists ot a number of alternate layers of flat metal and corrugated metal strips wound together on cylinder 9. Each coil is separated Jfrom the neat by an air space so that they will be in heat-insulating relation to each other. The number of coils and their spacing is determined by the heat capacity required and the consideration orI length-wise heat conduction between the two ends of the regenerator.

Broadly my invention comprises a regenerator havin a number of sections, each consisting cig a plurality of spaced metal leaves presenting an extended surface to the mediating air and disposed within a body of heat-insulating material in the path of the mediating air; each section being heatinsulated from the adjacent sections. lt is apparent that numerous forms of construction may be employed without departing from the scope of the invention as disclosed in connection with the embodiments illustrated.

l. closed cycle refrigerating system operating with gaseous mediating fluid, comprising in combination a plurality ot heat absorbing and delivering units, arran ed successively in the path of the mediating gas and in non-conductive relation to each other, means for insulating said units from outside environment, and means for causing the mediating gas to move past said units in succession.y

2. In a rerigerating machine,` a regenerator comprising a body of heat-insulating material, a plurality of sections having capacity for absorbing and giving up heat, arranged one after another within said body of heat-insulating material and forming aportion ot the path ot7 the mediating gas, each of said sections being heatinsulated from the adjacent section.

3. ln a refrigerating machine, a regenerator comprising inner and outer circular walls of heat-insulating material having an annular space between them to form a portion ot' the path of the mediating gas, a plurality of sections having capacity for absorbing and giving up heat, arranged within the annular space one after another but lili@ iis" heat-insulated from each other, said sections each presenting a large surface to the medi- *ating gas and having a plurality of narrow cular walls of heat-insulating material. having an annular space between them to form a portion of the path of the mediating air, and a plurality of spirally wound meta'llic ribbons in said annular space having their layers spaced -from each other to form air spaces between layers, said metallic ribbons being heat-insulated from each other.v

5. In an air refrigerating machine, a regenerator comprising a chamber having walls of heat-insulating material and forming a portion of the path of the mediating air, and a plurality of sections each consisting of metallic ribbons in closely spaced relation to each other and arranged in the path of the mediating air to subdivide the air flow into a plurality of substantially equal small parts, said sections being separated so as to maintain them in heat-insulated relation to each other.

6. An air refrigerating machine comprising\a compression piston and a shifter piston, inner and outer concentric circular walls of heat-insulating material, the inner Wall forming a portion of the Wall of the cylinder in which said pistons reciprocate,

and the annular space between said two walls forming a portion of the path of the mediating air, and a plurality of heat absorbing and delivering units disposed in heat-insulated relation to each other within the said annular space.

7. An air refrigerating machine comprising a compression piston and a shifter piston, inner vand outer concentric circular walls of heat-insulating material, the Ainner wall forming a portion of the wall of the cylinder in which said pistons reciprocate, and the annular space between said two walls forming a portion of the path of the mediating air, and a pluralityA of coils of metallicribbons spirally Wound on said inner wall in spaced relation to each-other, the layers of eachl of said coils being` spaced from each other by ay plurality of circumferentially spaced strips of heat-insulating the material extending along elements of cylinder.

WAR LUNDGAARD.

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