US3062022A - Heat pump - Google Patents

Description

WIR".

Nov. 6', 1962 J. R. AVERILI. ETAL HEAT PUMP 3 Sheets-Sheet l Filed Dec.. 15, 1959 .NQS

ATTORNEYS.

Nov. 6, 1962 J. R. AvERlLl. ETAL 3,062,022

HEAT PUMP l Filed uw. 15.'A 1959 A s sheets-sheet 2 41"! INVENTORS.

.Ja/.w .e Ausg/L BY Sues EMMA/VN, Je.

ZLJZL ATTOBN EVS Patented Nov. 6, 1962 Filed Dec. 15, 1959, Ser. No. 859,742 9 Claims. (Cl. 62-402) This invention relates to a heat pump, composed of two collapsible wall type expansion engines of the type disclosed and described in U.S. Letters Patents No. 2,581,830 in the name of John R. Averill, and No. 2,691,365 in the name of Sears Lehmann, Ir. In these patents, it was pointed out that mechanically, `an expansion engine, a compressor, a prime mover or pump and a meter are exactly the same. The present invention utilizes two engines of this type, one as a compressor and one as an expander, to form a heat pump or air conditioner with air as the only refrigerant.

Commercial machines have been built employing air as a refrigerant, but for the most part, these machines have been used for making ice, and show a very low coefficient of performance. For air conditioning purposes, much lower differentials are necessary, and the theoretical coefficient of performance would be much higher.

It is therefore an object of the present invention to combine two units of the improved expansion engine as disclosed in the previous patents, using one as a compressor and one as an expander in such a way that an air conditioner results which uses air as the sole refrigerant. No intermediate refrigerant would be required; thus one heat transfer operation, as well as the complications attending use of a condensable refrigerant are eliminated.

It is a further object of this invention to provide a machine in which the heat transfer is from air to air; heat is transferred from the air being compressed and then expanded, to a ow of cooling air.

Yet another object of this invention is a machine in which much of the power required to drive the compressor section of the entire unit is recovered from the expansion section.

One more object of this invention is a machine in which the compressor handles the circulation of all air subjected to cooling, so that no separate blower system is needed.

An additional object of the invention is a machine in which the heat transfer function takes place at higher temperatures, so that the cooling coils remain dry. This is a further advantage because condensation impairs heat transfer, and may produce objectionable odors.

These and other objects of the invention, which will be set forth in more detail hereinafter, or which will be apparent from a study of the specifications by one skilled in the art, are accomplished by that certain construction and arrangement of parts of which the following describes certain exemplary embodiments.

Reference is made to the drawings forming a part hereof and in which:

FIGURE 1 is a vertical cross sectional view taken on line 1 1 of FIGURE 2 or 3;

FIGURE 2 is an end elevational view of my invention;

FIGURE 3 is a cross-sectional view of the same taken on line 3 3 of FIGURE l;

FIGURE 4 is a greatly enlarged fragmentary view of a portion of the ring of FIGURE 3 showing the manner of attachment of the flexible strip to the ring;

FIGURE 5 is a greatly enlarged fragmentary view of a portion of the hub of FIGURE 3 showing the connection of the opposite ends of the metal strip forming the hub, and their connection to the exible strip forming he expansion and compression chambers;

FIGURE 6 is a fragmentary cross-sectional view similar to the central portion of FIGURE l, on a greatly enlarged scale showing the flange between the compression and expansion chambers, `and the means of securing this flange to the two rings;

FIGURE 7 is a cross-sectional view taken on the line 7 7 of FIGURE 1; and

FIGURE 8 is a set of four diagrammatic representations of the hub, ring, and strip at intervals of rotation.

Briefly, in the practice of the invention two machines are provided as described in the previous patents, in which the flexible strip comprising the collapsible wall is wound in opposite directions. In other Words, the two sections are mirror images of each other. They both are mounted on the same shaft, and are locked together, turning in the same direction and at the same speed.

In the first section the warm incoming air is compressed under the flexible strip and under compression of course, the temperature of the gas rises considerably. While undergoing compression, some of the heat is lost to the cooler hub. From the compression chamber, the hot, compressed air is forced down through a spiral passageway to the hollow center of the hub, then through this hollow center into the expansion section, and finally out the reverse spiral passageway in the expander hub. While traveling through all these passageways the compressed air transfers its heat of compression through the Walls of the passageways to cooler air drawn axially through hollow portions in the hub.

The cooled compressed air is next allowed to expand adiabatically in the expander section. During this expansion its temperature falls, and mechanical energy is ex-V tracted to help drive the compressor.

In the expander section, the air is not completely expanded back to normal pressure, so that it will force itself out the cool air port, and cause itself to be recirculated.

Referring now more particularly to the drawings, there is shown in FIGURE l a drive shaft 10 rotating in bearings as at 11 and 12 outside the heat pump housing. Access to the rotating components inside the housing is gained by removing the housing cover. End anges 13 and I4 rotate with the shaft in openings in the housing end plates 15 and 16. Clearance between these parts is close enough to minimize leakage in or out, but not close enough to prevent free rotation. At 17 is shown a liange separating the compression and expansion chambers.

The hub sections between flanges 13 and 17 or 17 and 14 are formed from a thin metal strip 18, as seen in FIGURE 3. Opposite ends are fastened together at 19 and between these ends is the inner end of compression strip 20. (FIGURE 5 shows an enlarged view of this connection.) The edges of strip 18 are held in concentric grooves cut into the flange inserts 21, 22, 23 and 24. This Whole assembly is held together by three threaded rods 25, 26 and 27. The weight of the clamp 19 is counterbalanced by a heavy walled tube of equal weight 28, set on the opposite side an equal distance from the center. FIGURE 7 shows the hub section between flanges 14 and 17, and as can be seen, it is a mirror image of the section between flanges 13 and 17. Consequently, the same designations have been employed as to both hub sections. The two hub sections are then bolted to their respective outside flanges, 13 and 14. A flanged sleeve 29 and a threaded sleeve 30 are pinned to the shaft 10. End flanges 13 and 14 are held in position and forced together by these sleeves and nut 31. This compressive force holds the hub sections in place between the end anges and the intermediate ange 17. 'I'he sleeves which are pinned to the shaft are also keyed to the end flanges to permit transmission of torque without twisting the assembly.

Cylindrical rings 32 are located so that they can slide with a minimum clearance between flanges 13 and 17 or 17 and 14. Each of these rings has a flange 34 welded to its outer circumference, on the end nearest the intermediate ilange 17. These rings also have lengthwise slots milled into their inner surfaces, into which the outer ends of the compression or expansion strips 20 are fastened. FIGURE 4 shows an enlarged view of slots and the attachment of the compressor strip. A ring clamp assembly 37, 38 and 39 (seen best in the enlarged FIGURE 6), engages flanges 34 at their outer edges to position the two sections of ring 32 in axial alignment. This arrange ment permits changing the angular position of one ring with respect to the other by loosening the ring clamp. rotating one section of ring 32 and reclarnping the ilanges in the new position by tightening the machine screws 40, which draw 37 and 39 together. In `the above referred to patents, several positive mechanical linkage systems are described which enforce upon said securing means (ring) one revolution for each revolution of said hub. In the compressor expander combination such means are not necessary, and may even be undesirable. Since both the hub and the outer ring are common to the two sections, the apparatus will time itself. The linkage here is of a exible pneumatic nature which varies within certain mechanically imposed limits. These limits may themselves be varied by adjustment of the ring assembly 37-40 which holds the rings 32 together. Thus if the rings 32 are shifted to permit a slight unwrapping of the compressor and expander strips, the limits between which the strips may position themselves will be widened. With the strips incompletely wrapped, angular speed will be maintained constant by the inertia of the rings and yokes at normal operating speed.

These two sections of the outer ring are cradled in idler wheels, 41, which stabilize the rotation of the rings about a constant center, and maintain pressure between the hub and ring at the point of contact. At least one set of these idler wheels should be adjustable, so that the clearance between the hub and the outer ring at the point of contact may be changed.

Between the hubs 18 and the outer rings 32, a thin, llexible, impervious strip 20 is wrapped. It is exactly the same width as rings 32, so as to slide with a minimum clearance between flanges 13, and 17, or 17 and 14. As explained before, the inner end of the strip is fastened to the hub at 19 (FIGURE 5) and the outer end is fastened at 36 to the outer ring (FIGURE 4). The milled slot arrangement at 36 permits the strip to pivot without strain or leakage. An effective length of strip 20 is such that when the inner connection 19 is approaching the point of contact C, the outer end can be 180 displaced from said point of contact. It will be understood that the strip length can be varied without departing from the spirit of the invention.

A sealing ring 43 is attached to the housing partition 42. By adjusting the position of shaft in its bearings 11 and 12, the side of the ring clamp 37 is brought close enoughto form an eiective seal between the compressor and expander sections of the unit.

The hub sections of the compressor and expander assemblies are heat exchangers. As many holes as possible are drilled in the ange inserts 21, 22, 23 and 24, with matching holes in the flanges themselves. A fan rotor 49 is mounted outside flange 13 and thus is able to draw cooling air through ports at `47, ythrough the hollow portion 48 of the hub and out the exhaust ports 50.

In operation, warm air enters the machine at port 46 in the compressor section. In the outer ring in this section, holes 44 are drilled as shown in FIGURE 3, behind the point where the strip is joined to the outer ring, in terms of the direction of rotation. 'I'he air enters the compressor section through these holes 44, and is compressed in the crescent shaped section ahead of the strip. The four drawings A, B, C and D of FIG- URE 8 show diagrammatically four stages in this cycle. The dotted lines 60 in this group of diagrams show the position of the expander section inlet relative to the compressor section shown. At a point between stages B and C, the port in the hub of the compressor section is uncovered and the compressed air is forced into the spiral passage. As it travels toward the hollow center of the shaft, it is cooled by the retaining walls of the spiral passageway. In the inner chamber, it passes parallel` to the shaft, into the expansion section of the machine, and then spirals back out through the hub in the expander section. Once again, on its travel back out in the spiral passageway, it is being cooled by the air drawn through the sections 48 of the hub. It then leaves the hub assembly through port 19 in the expander section of the unit, and is then expanded adiabatically to almost atmospheric pressure, being greatly cooled in the process. Because of the slight excess pressure remaining, the air forces itself out exhaust port 45 in that portion of the outer ring in the expander section, and out the cool air duct 51 into the area to be cooled. As explained in the previous patents, this adibatic expansion of air transfers heat energy into mechanical energy, which is to help drive the other section of the machine. A pulley 52 is shown which may be driven by a small electric motor to provide power not supplied by the expansion section.

It will be understood that numerous modifications may be made without departing from the spirit of the invention and therefore no limitation is intended other than as pointed out in the claims which follow.

Structurally the herein disclosed device may be used as a heat engine, or as a fluid pump. If, for example, fuel is burned with the compressed air, heating rather than cooling it, the expander will yield primarily mechanical energy, and the result is a heat engine. It is also possible to utilize this combination as a uid pump. In these cases there need be no heat transfer section. Liquid or gas under pressure may be fed through a stuffing box into the hub of an expansion engine which will drive a pump or compressor section whose outer ring is yoked to that of the engine as with the heat pump. Exhaust from the engine may comingle with lluid to be pumped if the intake volume of the pump is greater than the exhaust volume of the engine, or the two streams may be sealed apart as is done with the heat pump. Hub sections of the expander and pump will have to be separated of course, and pressured uid will pass out the pump hub through another stutling box.

With the foregoing considerations in mind, it will be understood that in the specifications and claims wherever the language will permit the phrase heat pump is used in a general sense and is intended to cover the apparatus whether it is used as a heat pump or a heat engine or a fluid pump.

Furthermore, while the device herein described is shown as being air cooled, it may of course be water cooled without departing from the spirit of the invention.

Having now fully described the invention, what is claimed as new and what it is desired to secure by Letters Patent is:

1. A device of the character described comprising (a) a compressor of the collapsible wall type with a tluid inlet and a uid outlet, a shaft, a hollow hub mounted `on said shaft, a larger hollow ring surrounding said hub, means for holding said ring in tangential relation to said hub, an impervious flexible strip secured at one end to said hub and at the other end to said ring, end flanges confining said hub, hollow ring, and strip on said shaft, and means for rotating said hub to compress the fluid and force it toward the hollow center of said hub, (b) means for changing the temperature of said uid after compression but before expansion, and (c) an expander of the same type as said compressor, the inlet of said expander being in communication with the outlet of said compressor, said expander being mounted on the same shaft, turning at the same speed, and in the same direction as said compressor for expanding the fluid to exhaust pressure.

2. A machine according to claim 1, in which said compressor and expander hubs are mirror images of each other and are formed of several concentric annuli with connections between alternate annuli resulting in a substantial spiral passageway toward the center of the cornpressor hub and outward in the expander hub, and providing hollow cooling spaces between said annuli.

3. A machine according to claim 2, in which air is caused to pass through said cooling spaces to abstract heat from said compressed air.

4. A machine according to claim 3, in which the cooling takes place at an elevated temperature.

5. A machine according to claim l, in which the hubs and rings respectively of the `compressor and expander sections are physically linked together whereby the end of each said strip is caused to make one revolution for each revolution of its respective hub.

6. A machine according to claim 5, in which some, at least of the power to drive the compressor is derived from the expander,

7. In a heat pump, a pair of coaxial anged hubs, each of said hubs having a convoluted entrance passage extending from the outside of said hubs between the respective flanges, into the center, the centers of said hubs being in communication with each other, each of said convoluted passages being in heat exchange relationship with other passages arranged for axial ow of a cool-ant therethrough, a hollow ring freely encircling each of said hubs between the respective anges, and means for holding said rings and hubs in tangent relationship, and an impervious flexible strip having two ends associated with each said hub and ring, and secured =at one end -to the respective hub and -at lthe other end to the respective ring, the said exible strips being spirally arranged in the opposite sense with respect to eachother, means for rotating said hubs in a given direction whereby the apparatus associated with one of said hubs functions Ias a compressor and the apparatus associated with the other of said hubs functions as an expander, a port associated with said compressor through which hot air may enter to be compressed in said compressor `and cooled in the hub -thereof, whereupon said cooled compressed air passes into the hub of said expander to be further cooled in the hub thereof and then to be expanded in said expander, and an outlet port associated with said expander.

8. An apparatus according to claim 7, wherein said hubs are locked together and said rings are locked -togethe'r whereby the maintenance -of a proper orientation between the respective hubs and strip ends is insured.

9. A device of `the character described, comprising a compressor of the collapsible wall type having a fluid inlet, Ia shaft, a hollow hub mounted on said shaft, a larger hollow ring surrounding said hub, means for holding said ring in tangential relation to said hub, and an impervious exible strip, secured at one end to said hub and at the other end to said ring, means for rotating said hub to compress said fluid and yforce it toward the hollow center of said hub, an expander of the same type as lsaid compressor, mounted on the same sli-aft, turning it at the same speed and in the same direction, lthe rings of said compressor and expander being locked together, means for passing said fluid through said expander in a direction opposite its passage through said compressor, a uid outlet for said expander, and a pair of end anges confining said compressor and said expander on their com-mon shaft.

References Cited in the lle of this patent UNITED STATES PATENTS 801,182 Creux Oct, 3, 1905 1,199,486 Nauer Sept. 26, 1916 2,524,066 Andersen Oct. 3, 1950 2,581,830 Averill Jan. 8, 19'52 2,691,365 Lehmann Oct. 12, 1954 2,762,557 Jendrassik Sept. 11, 1956 2,796,746 Morrison June 25, 1957

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