US2530648A

US2530648A - Combination accumulator, heat exchanger, and metering device for refrigerating systems

Info

Publication number: US2530648A
Application number: US699490A
Authority: US
Inventors: Jr Martin T Cahenzli; Muffly Glenn
Original assignee: HARRY ALTER Co
Current assignee: HARRY ALTER Co
Priority date: 1946-09-26
Filing date: 1946-09-26
Publication date: 1950-11-21
Anticipated expiration: 1967-11-21

Description

Nov. 21, 1950 M. T. CAHENZLI, JR. ETAL 2,530,648

COMBINATIQN'ACCUMULATOR, HEA'I EXCHANGER, AND METERING DEVICE FOR REFRIGERATING SYSTEMS Filed Sept. 26, 1946 Patented Nov. 21, 1950 COMBINATION ACCUMULATOR, HEAT EX- CHANGER, AND METERING DEVICE FOR REFRIGERATING SYSTEMS Martin T. Cahenzli, Jr., Chicago, 111., and Glenn Muffl'y, Springfield, Ohio, assignors to The Harry Alter Company, Chicago, 111., a corporation of Illinois Application September 26, 1946, Serial No. 699,490

9 Claims.

1 s This invention relates to improvements in a combination unit for refrigerating systems, and more particularly to a unit readily installed with a minimum of labor in the suction side of a refrigerating system, the unit containing means to function as a metering device for fluid passing through the high pressure side of the system, and

as a. heat exchanger, or in another form as a combination accumulator, heat exchanger, and metering device, although the invention may have other uses and purposes as will be apparent to 1 one skilled in the art.

It is now'accepted in the trade that a highly satisfactory way of controlling the flow of refrigerant from theconde'nser to the evaporator in a refrigerating system is by means of a metering tube, sometimes referred to as a capillary tube. Such a tube restricts the flow of refrigerant by virtue of its small internal diameter, by virtue of the shaping of the tube, or by virtue of a combination of both. It is also desirable to effect a heat exchange in the system so that the liquid refrigerant passing to the evaporator may be initially chilled to a considerable extent before it reaches the evaporator thus lessening the load on the compressor and cutting down the operation of the mechanically moving parts of the system in the event it is an automatic stop and start system; This is most frequently accom- .,plished by associating a portion of the pressure lineintimately with'the suction line so that the refrigerant traveling through the suction line becomes warmer'by the extraction of heat from the refrigerant in the pressure line.

In the past, various arrangements have been provided to efiect such a heat exchange, and these previously known arrangements were objectionable in many instances because of the considerable expense for their installation, and in many instances because they did not eilect heat exchangeto a desirable extent. Difliculty was frequently experienced in determining whether or not the heatexchange installation was war-- porated in the system. That is, where an accumulator, a heat exchanger, and means for controlling the flow of refrigerant were desired, all of these were incorporatedin the system as separate devices.

p I with theforegoing in mind, it is an important 2 object of the instant invention to provide a heat exchange arrangement between a metering tube and the suction line of a. refrigerating system that effect an extremely high amount of heat exchange. I

Another object of the invention is the provision of a heat exchange arrangement wherein a metering tube is associated for heat exchange purposes with a part of the suction line of a refrigerating system in an extremely economical manner.

Another object of this invention is the provision of a simple economical combination unit embodying both a metering arrangement and a heat exchanging arrangement, which unit may be easily and economically installed in a refrigerating system with a minimum of labor.

It is also an object of this invention to provide a combination unit for installation in a refrigerating system, which unit embodies an accumulator, a metering tube, and a heat exchanging arrangement of exceptionally high emciency, the entire unit being installable at once in the suction line of a refrigerating system.

It is also a feature of this invention to provide a unit for installation in a refrigerating system, which embodies a casing for connection in the suction line of the system, and a metering tube having a goodly portion thereof disposed within the casing, with the tube so arranged as to provide a minimum amount of restriction to the flow of refrigerant while the major portion of the heat exchange takes place, and to provide a higher restriction to the flow of refrigerant while the remainder and considerably lesser portion of the heat exchange operation takes place.

Still another ob.ect of this invention resides in the provision of a unit for installation in a refrigerating system, which unit includes a casing for connection in the suction line of the system, and a metering tube having a goodly portion thereof disposed inside the casing, that portion of the metering tube being of uniform size throughout, and so shaped that the portion through which refrigerant first passes in traveling to the evaporator affords a minimum restriction to the flow of refrigerant, while that part of the tube portion in the cas ng through which refrigerant later passes affords a very high re striction.

While some of the more salient features, characteristics and advantages of the instant invention as mentioned have been above pointed out, others will become apparent from the following trated.

disclosures, taken in conjunction with the accompanying drawing, in which:

Figure 1 is a somewhat diagrammatic view of a refrigerating system, showing a unit embodying principles of the instant invention as connected in operative position in the system, the unit itself being shown in section;

Figure 2 is an enlarged part sectional part elevational view of the unit itself removed from the refrigerating system;

Figure 3 is a vertical sectional view, with parts in elevation, of a unit embody g principles of this invention but of somewhat different construction than that seen in Figures 1 and 2; and

Figure 4 is a transverse vertical sectional view through the right hand portion of the metering tube of Figure 3.

As shown in the drawings:

In Figure 1, the first illustrated embodiment of the instant invention is shown installed in a refrigerating system, diagrammatically illus- This refrigerating system includes a compressor I connected by a suitable fluid line 2 to a condenser 3. The condenser is in turn connected through a metering tube 4 to an evaporator 5. A portion of the metering tube 4 is incorporated in the unit generally indicated by numeral 6 which embodies improvements of the instant invention. This unit is connected in the suction line of the system so as to form a part of that line, and may be connected directly to the outlet of the evaporator or to an outlet conduit 1 from the evaporator as illustrated, and the opposite end of the unit is connected to the usual suction line 8 leading back to the compressor I. If it is desired to employ a reservoir in association with the condenser, such may be done, and the instant invention will not affect the operation of the system including the reservoir in any degree.

It is, of course, preferable to have the unit itself disposed as closely to the evaporator as possible, because the gasified refrigerant leaving the evaporator is colder in that region. It will be especially noted that the entire unit may be incorporated in the refrigerating system with only one more connection than is required for the system without the unit. That would, of course, be a connection to one end of the unit. And yet, with the provision of the unit illustrated in Figures 1 and 2, the system is provided with an accumulator, a heat exchanger, and a metering device for controlling the flow of refrigerant to the evaporator, as will more fully later appear.

The unit 6 itself embodies a hollow casing 9 larger than the component parts of the suction line 8 so as to define an interior chamber to that may function as an accumulator. At one end thereof the unit is provided with a fitting H for connection directly to the evaporator outlet or to an outlet conduit 1 as shown in Figure 1, and at the other end the unit is provided with a fitting I! for connection with the suction line 8. Inside the casing 9 is an upwardly inclined pipe l3, one end of which is associated with the fitting I! in such manner that the pipe forms substantially an integral part of the suction line. The opposite end of the pipe is disposed at a high point, desirably above the fitting H, and this end of the pipe is freely open. Consequently, if upon the sudden starting of the compressor I, a slug of liquid refrigerant is withdrawn from the evaporator, that slug will pass through the fitting H and fall to the bottom of the chamber ll.

slug will thereupon easily and only the gasified refrigerant will pass through the pipe I! and the suction line 8 to the compressor, thus avoiding injury to the compressor b way of a slug of liquid reaching it.

A goodly portion of the metering tube 4 is disposed inside the casing I, and it will be understood that where the tube 4 enters and leaves the casing suitable sealing means are employed. This tube 4, of course, carries liquid refrigerant from the condenser I to the evaporator I. The tube is designed so that at the same time it carries this liquid refrigerant, it meters or governs the quantity of liquid refrigerant delivered into the evaporator.-

Such a tube that is substantially straight or wound into a relativeLv large coil requires a considerable length to effect the desired or required restriction to refrigerant flow. It is therefore desirable to shape the tube to increase the restriction and thus shorten the length necessary for any particular installation. It is easy to place the required length of tubing, shaped to increase restriction, inside the casing 9, and that portion of the tubing inside the casing is obviously in heat exchange relationship with the fluid passing through the suction line I from the evaporator. v

A problem is presented in acquiring the optimum amount of heat exchange. If the tube is highly restricted to refrigerant flow, the pressure obviously must drop, and as the pressure drops the evaporation point or temperature at which the refrigerant gasifies also drops. Therefore, while it is known that the temperature is dropping in the refrigerant under pressure, if that pressure is permitted to rapidly drop also a common point at which the refrigerant gasifles will be reached prematurely, and thereafter there is no need for any further heat exchange, and the refrigerant is gasifying in the metering tube rather than in the evaporator to the detrimental operation of the entire system.

The instant invention very capably solves this problem. As seen more clearly in Figure 2, that portion 44 of the tube 4 inside the casing 9 through which the refrigerant first flows is coiled loosely around the pipe [3. It has been found that if this coiling is done so as to maintain an inside coil diameter of one half inch or more there is negligible restriction caused by the tube over that of a straight tube. Consequently, the loosely coiled portion I4 affords minimum restriction and thus the high pressure is maintained. However, while the refrigerant is passing through the part i4 of the tube 4 the temperature of the refrigerant is lowered materially by virtue of the heat exchange action. The remainder of the tube 4 inside the casing 9 is wound in the form of a tight coil of very small inside diameter, and then this coil is in turn coiled around the pipe I: as indicated at I! thus expanding the turns of the original coil. Coiling a metering tube this fine results in greatly increasing the restrictive powers of the tube. Pressure, ,of course, will drop rapidly in the portion ii of the tube, but by the time the pressure is dropping in that portion of the tube, the temperature of the refrigerant has been so materially reduced that gasifying of the refrigerant cannot occur. Thus the refrigerant will not vaporize until it reaches the evaporator, or only to a negligible extent immediately before it reaches the evaporator. At the same time, a great amount of The 7 heat exchange has been efiected and the ellia ciency of the entire system is thereby materially increased. Aconsiderably greater amount of heat exchange can be effected with the invention as above described than has heretofore been accomplished by previously known means.

In most instances in actual practice, there will be a suflicient length, of tube 4' projecting from the unit 6 to establish connection with the evaporator and the condenser. Thus it can be seen that the entire unit is extremely economical, and veryeasily installed in a refrigerating system, providing an accumulator, a heat exchanger, and a metering device all in the one unit.

In Figures 3 and 4-1 have illustrated another unit Ii, which, embodies only a heat exchanger and a metering device. This unit is highly satisfactory in the event an accumulator is not desired Unit I 6 embodies a casing ll which may beconnected to the aforesaid outlet conduit 1 from the evaporator at one end and at the other end to the suction line 8, as above described. Inside the casing H a goodly portion of a metering tube in is disposed. The part of that portion through which the refrigerant first travels is in the form of a, loosely wound coil Ila of sufficiently great diameter as to provide a minimum amount of restriction. The remainder of that portion of the tube is in the form of a coiled coil i5a, the original coil of which has an extremely small diameter so that restriction is very high, and the original coil is itself coiled as above explained to occupy a smaller space and to expand the turns of the original coil as illustrated at I8 in Figure 4. The showing in Figure 4 insofar as actual structure is concerned applies equally as well to the portion ii of the metering tube seen in Figure 2 as it does to portion l5a of. the metering tube seen in Figure 3. With the structure of Figure 3, the operation issubstantially the same as above described except that there is no accumulator action, and the same high amount of heat exchange is effected.

Of course, in both embodiments of the invention there will be some restriction to the flow of refrigerant in the parts It and Ila of the

tubes

4 and 4a respectively, but as above stated that restriction is of very little amount in comparison with the restriction occurrent in the portions 15 and lid of these tubes. Of course, in the overall installation the restriction in the portions l4 and Ma as well as the parts of the respective tubes outside the casings is taken into consideration in determining the total amount of restriction desired before the refrigerant reaches the evaporator. This amount of restriction, however, is very easily established by virtue of the fact that the portions l4 and Ma of the respective tubes afford substantially no more restriction than does a straight length of tube. Since by far the greater amount of restriction occurs in the portions l5 and [5a variations to fit different systems may readily be made here.

From the foregoing, it is apparent that I have provided a novel and highly efficient unit for incorporation in a refrigerating system. The unit may be easily installed, and effects an extremely high degree of heat exchange as well as providing adequate metering means for controlling the flow of refrigerant to an evaporator. If so desired, the unit may be made to function as an accumulator as well. The entire unit is simple in construction, highly durable and economical to manufacture.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated bythe scope of the appended claims.

We claim as our invention:

l. A combined metering tube and heat exchanger unit for connection in refrigerating system. including a housing arranged forconnection near the evaporator in the suction side of the system, and a metering tube for connection in the pressure side of the system, said tube having'a relatively large portion thereof inside said housing, said portion on the incoming sideaffording relatively low restriction and on the outlet side being coiled into a coil of small inside diameter to provide high restriction to the .flow of refrigerant. Y .1 I y 2. A combined metering tube and heat exchanger unit for connection in a'refrigerating system, including a housing arranged for connection near the evaporator in the suction side of the system, and a metering tube for connection in the pressure side of the system, a portion of said tube being within said housing, a part of said portion on the incoming side being coiled with a sufficiently large diameter to afford little restriction, and the part of said portion on the outlet side being coiled into a coil of small inside .diameter to provide high restriction to the flow of refrigerant.

3. A combined metering tube and heat exchanger unit for connection in a refrigerating system, including a, housing arranged for connection near the evaporator in the suction side of the system, and a metering tube, for connection in the pressure side of the system, a portion of saidtube being within said housing, a part of said portion on the incoming side being coiled with a sufliciently large diameter to afford little restriction, and the part of said portion on the outlet side being coiled and recoiled in a manner to expand the loops of the first coil to provide high restriction and added surface exposure of the tube.

4. A combined metering tube and heat exchanger unit for connection in a refrigerating system, including a housing arranged for connection near the evaporator in the suction side of the system, and a metering tube for connection in the pressure side of the system, said tube having a relatively large portion inside said housing, said portion on the incoming side afiording relatively low restriction and on the outlet side being coiled into a coil of small inside diameter to provide high restriction to the flow of refrigerant, said metering tube being of the same size throughout said portion.

5. A combination unit for inclusion in a refrigerating system, comprising a casing, a fitting on each end of said casing connecting the casing in the suction side of a refrigerating system, an upwardly inclined open ended pipe in said casing and connected to the fitting on the compressor side of said casing, and a metering tube for connection in the high pressure side of a refrigerating system, a portion of said tube being inside said casing, a part of said portion being loosely wound around said pipe in a coil sufficiently large to provide a minimum of restriction to the flow of refrigerant and the remainder of said portion being wound into a coil of sufficiently small diameter to provide high restriction.

6. A combination unit for inclusion in a reasses 7 fri ersting system. comprising a casing. a fittin on each end of said casing for connecting the casing in the suction side of a refrigerating system, an upwardly inclined open ended pipe in said casing and connected to the fitting on the compressor side of said casing, and a metering tube for connection in the high pressure side of a refrigerating system. a portion of said tube being inside said casing, a part of said portion being loosely wound around said pipe in a coil sufficiently large to provide a minimum of restriction to the flow of refrigerant and the remainder of said portion being wound into a coil of sufficiently small diameter to provide high restriction, said small diameter coil being coiled about said pipe in a manner to separate the turns of the small diameter coil.

7. In a combination accumulator, heat exchanging and metering unit for a refrigerating system, a hollow casing for connection in the suction side of the system, a metering tube for connection in the high pressure side of the system, and a portion of said tube being inside said casing, a part of said portion being loosely arranged to provide minimum restriction and of a material length sufficient to cause a substantial drop in temperature of the refrigerant therein, and a part of said portion being finely coiled to provide high restriction to the flow of refrigerant.

8. In a combination accumulator, heat exchanging and metering unit for a refrigerating system, a hollow casing for connection in the suction side of the system, a metering tube for connection in the high pressure side of the system, and a portion of said tube being inside said casing, 'a part of said portion being loosely arranged to provide minimum restriction and of a material length sumcient to cause a substantial drop in temperature of the reirigerant therein. andapartofsaidportionbeingfirmlyeoiled to provide high restriction to the flow of refrigerant, said tube being of the same internal diameter throughout said portion.

9. In a combination unit for incorporation in the suction side of a refrigerating system, a hollow casing through which refrigerant may pass in returning from the evaporator to the com- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 7 Date 2,181,416 Boles Nov. 28, 1939 2,188,893 Philipp Jan. 30, 1940 2,393,854 Carpenter Jan. 29, 1946 2,455,298 Cahenzli Nov. 30, 1948 FOREIGN PATENTS Number Country Date 11,177 Great Britain 1896