US 2500688 A
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March 14, 1950 E. P. KELLJE 2,500,688
REFRIGERATING APPARATUS Filed Aug- 24. 1948 2 sheets-sheet 1 u mann-.Lugwww Wauu-arr. unna ATTOQNEK.
E. P. KELLIE REFRIGERATING APPARATUS I 2 Sheets-Sheet 2 INVENTOR. Edward 7? /62//1'e BY 2 ATTORNEYS.
March 14, 1950 Filed Aug. 24, 1948 Patented` Mar. 14,. 1950' UNITED STATES PATENT OFFICE REFRIGERATING APPARATUS Edward l. lieliianetroit, Mich.
Application August 24, 1948, Serial No. 45,868
This invention relates to refrigerating apparatus and more particularly to a refrigeratlng apparatus which will maintain the refrigerator cabinet at very low temperatures. for example, 120 below zero F. or even lower.
It is an object of this invention to produce a low temperature refrigerating apparatus which is eiiicient in operation, of simple structure, and economical to build.
The invention contemplates a low temperature refrigerating apparatus in which the liquid refrigerant is cooled to a low temperature before it is evaporated to produce the desired low temperature in the refrigerator cabinet. Although the refrigerating or cooling of the liquid refrigerant preparatory to evaporating the same to produce low temperature refrigerating can be effected by an external refrigeration cycle; it is preferred to effect this refrigeration by an internal refrigerating cycle.
In the drawings:
Fig. 1 is a vertical view in cross section of a refrigerating apparatus embodying my invention.
Fig. 2 is a vertical cross section of a modified form of my invention.
Referring more particularly to the drawing, my refrigerating apparatus comprises a motor compressor unit I, the high side or outlet of which is connected by pipe line 2 with the low side or inlet of motor compressor unit 3. The high side or outlet of motor compressor unit 3 is connected by pipe line 4 with condenser 5 in which the compressed refrigerant is cooled and liquefied. The liquid refrigerant is conducted by pipe line 6 to a high side float valve chamber 1.
The float valve is designated l and controls the flow of liquid -refrigerant from chamber 1 through line 9 to a second high side oat chamber Ill which is positioned outside the insulated refrigerator cabinet II but within a separate insulated compartment 25.
The bottom wall Il of float chamber Ill is provided with an outlet I2 which is connected by pipe line I4 to the low temperature evaporator I5 within the cabinet I I. The low temperature evaporator I is connected at its outlet (at the top preferably) to inlet I1 in the lower part of the accumulator I6. Accumulator I5 is, of course, located within cabinet II. Pipe line Il connects outlet I9 in the upper wall of accumulator I5 with the low pressure side or intake of motor compressor unit I. Float chamber Il is provided with an outlet 20 above the liquid level which is connected by pipe 2| to line 2 between motor compressor units I and I.
A manually adjusted valve 22 or other suitable restrictor controls the flow of gaseous refrigerant through line 20. Valve 22, or other suitable restrictor, actuated by float 24 in chamber I0. controls the flow of liquid refrigerant from chamber I0 into line I4 and evaporator I5. Float valve 8 closesoif line il whenever the liquid refrigerant in chamber 1 falls below a predetermined level and float valve 23 closes port I2 whenever the level of the liquid refrigerant in chamber III falls below a predetermined level. The level of the liquid refrigerant in chamber I0 is always maintained below outlet port 20. e The operationef my refrigeration apparatus is as follows: Gaseous refrigerant from line I8 is compressed in motor compressor unit I to a predetermined pressure and delivered through pipe line 2 to motor compressor unit 3 which compresses the gaseous refrigerant to a higher predetermined pressure and delivers the gaseous refrigerant at this higher pressure through line 4 to condenser 5. The highly compressed refrigerant is cooled and condensed to a liquid in condenser 5 and the liquid refrigerant passes through line 6 to oat valve chamber 1. Float valve 8 controls the feed of liquid refrigerant through line 9 to float chamber III. Since my invention contemplates refrigerating or cooling the liquid refrigerant to a low temperature, say, for example, in the neighborhood of zero degrees F. before it is evaporated, I accomplish this refrigeration of the liquid refrigerant by an internal refrigeration cycle. I prefer, however, to accomplish this refrigeration by an internal cycle using the same refrigerant that I use for refrigerating the cabinet II. Further, I prefer to refrigerate the liquid refrigerant within chamber It by direct action of the refrigerant refrigerating itself and thus avoid efficiency loss which would occur if heat transfer were required to pass between walls of separate vessels. Note also that chamber Ill also is the metering device to the next stage thereby further increasing the efficiency of the unit.
This is accomplished by connecting chamber Il) with the low side of compressor 3. Float valve I serves as a restrictor to effect a pressure drop between line 6 (the high side of float valve l) and line 9 and chamber III (the low side of valve 8). A restrictor such as float valve 8 is preferred, but a so-called conventional capillary tube restrictor, that is,-a tube of such small diameter and length as to give the required pressure drop, can be substituted for float valve I. The reduced pressure in chamber III will cause some of the liquid refrigerant in chamber Il to evaporate and the gas will be drawn oif through line 2l and valve 22 back to the low side of motor compressor 3. The valve 22 or other suitable restrictor can be adjusted to control or regulate the amount of refrigerant gas which is withdrawn from chamber I0. The evaporation of the liquid refrigerant in chamber II) withdraws heat from the liquid refrigerant in chamber I0.
This evaporation of the refrigerant in chamber I can-be lcontrolled to considerably reduce the temperature of the liquid refrigerant in chamber IIII and evaporator I5 and preferably the liquid in chamber I0 is cooled down to a lower temperature, for example, zero degrees F. Float valve 23 opens and remains open as long as the level of the refrigerant in chamber I0 is at some pre determined or desired level but always lower than that of outlet 20. It, of course, would be desirable to have liquid refrigerant drawn through line 2|. The precooled liquidrefrigerant now flows through line Il into evaporator I5 and thence to accumulator I6. Since evaporator I5 and accumulator I6 are on the low side of valve 23 and are connected with the low or suction side of motor compressor I, this drop in pressure will cause the liquid refrigerant in evaporator I5 to evaporate thus withdrawing heat from the liquid refrigerant in evaporator I5 and accumulator I6. The liquid refrigerant in evaporator I5 and accumulator I6 picks'up the heat within cabinet I I and this heat exchange lowers the temperature within cabinet II to sub-zero temperatures, in the neighborhood of -70 F. in the case of two stage compression or even lower depending upon the refrigerant used and refrigerating capacity of the system. It is, of course, understood that the temperature within cabinet II is controlled in a conventional manner by a suitable thermostatic switch so positioned as to control the operation cf the motor compressor units I and 3, in response to temperature within cabinet II, that is, rwhen the thermostatic switch calls for refrigeration, motor compressor units I and 3 will be set in operation and when the cabinet II is refrigerated to the low temperature desired the switch will respond to shut of the motor compressor units. This can also be accomplished by use of pressure operated controls. It will be noted that outlet I9, which connects with suction line I8, is located preferably in the top wall of accumulator I6 so that outlet I9 will always be located above the liquid level in accumulator I6. My refrigerating apparatus will be charged with refrigerant in a conventional manner so that the liquid refrigerant level in evaporator I5lwill never at any stage in the operation of my refrigerating apparatus reach outlet I9.
From the above it is evident that the refrigerant in lines 4, 5 and 6 is underthe highest compression and the refrigerant in evaporator' I5, accumulator I5 and line I8 is under the lowest 1 pressure, which may even be sub-atmospheric,
and that the refrigerant in line 9, chamber I0 and line 2| above valve 22 is at an intermediate pressure 'but higher than the pressure of the refrigerant in line 2.
and the third compressor 3 compressing the re.
frigerant to a higher and final pressure than that produced by the second compressor and with the three compressors there will. of course, be used an additional high side fioatidentical/to high side float I0 and mounted between float I0 and evaporator I5 and this third high side float chamber will be connected intothe refrigerant line running between the second and third compressors. In such three stage compression refrigerating unit the liquid refrigerant from the condenser 5 will be reduced to about zero degrees F. in the first precoolin'g iloat chamlber and to about 30 below zero F. in the second precooling oat chamber so that the liquid refrigerant enters the primary evaporator I5 at about -30 F. and evaporation of such liquid in primary evaporator I5 will reduce its temperature tof-120 F. or lower in the third stage of evaporation. For still lower cabinet temperatures additional stages of compression with additional prechilling float valves and chambers will be used.
I use the words primary and secondary evaporators in the sense thatthe primary evaporator is the evaporator (I5, I6) that does the most work or refrigeratingand goes to the lowest temperature while the secondary evaporator is float chamber IIJ which prechills the liquid entering the primary evaporator. It should be noted that the secondary evaporator I0 is separately insulated to prevent the refrigerating liquid therein from picking up heat from external sources and also to prevent it giving oi heat to the lower temperature refrigerating liquid in the primary evaporator.
1. Refrigeration apparatus comprising in combination a primary compressing means and a plurality of secondary compressing means connected in series for compressing a gaseous refrigerant to a desired pressure in multiple stages, a condenser communicating with the high side of the said secondary compressing means which compresses the said refrigerant to its final stage of pressure` a compartment to be refrigerated, a primary evaporator in said compartment, a plurality of secondary evaporators located without said compartment and connected in series, said primary and secondary evaporators corresponding in number to said plurality of primary and secondary compressing means, means including a restrictor connecting one of said secondary evaporators with the condenser, means including a restrictor connecting another of said secondary evaporators with the primary evaporator, con- I have described above and shown a two stage This two stage compression refrigerating apparatus will efficiently produce cabinet temperature of say 100 below zero F. or lower, then it is preferred to use three stage compression, that is,
three compleSSors willbe used, the second corn- `multiple compression refrigerating apparatus.
duits for placing each of said secondary evapora-` tors in communication with the low side of its respective secondary compressing means whereby some of the liquid refrigerant owing into said secondary evaporatorsvaporizes and withdraws heat from the liquid refrigerant in said second evaporators, said primary evaporator being connected to the low or intake side of said primary compressing means whereby the liquid refrigerant in said primary evaporator vaporizes and withdraws heat from the liquid refrigerant in. the primary evaporator and from within the compartment to be refrigerated.
2. The refrigerationvapparatus as claimed in claim 1 including arestrictor for controlling the flow of gaseous refrigerant through each of the conduits connecting the secondary evaporators with the low sides of their respective secondary compressing means.
3. Refrigeration apparatus comprising in combination first and second compressors, a conduit connecting the outlet port of the rst compressor with the inlet port of the' second compressor whereby gaseous refrigerant under pressure is delivered from the first compressor to the second compressor, a condenser communicating with the high side or outlet of the second compressor whereby said gaseous refrigerant is delivered ata higher pressure to said condenser wherein the gaseous refrigerant is condensed, a compartment to be refrigerated, a primary evaporator in said compartment, a secondary evaporator positioned outside of said compartment, a conduit including a restrictor connecting the secondary evaporator with the condenser iereby the pressure between the restrictor and ie condenser is higher than the. pressure in said secondary evaporator. a conduit connecting said secondary evaporator with the low side of said second compressor whereby some of the liquid refrigerant flowing into said secondary evaporator evaporates and withdraws heat from the liquid refrigerant in said secondary evaporator. a conduit including a restrictor connecting s'aid secondary evaporator with said primary evaporator whereby the pressure in said primary evaporator is lower than in the secondary evaporator, said primary evaporator being con- 6 nected to the low or intake side of the said iirst compressor at a point which will always be above the liquid refrigerant level in said primary evaporator whereby the liquid refrigerant in said primary evaporator evaporates and withdraws heat from the liquid refrigerant in said primary evaporator and from within the compartment to be refrigerated, the second restrictor being in the form of a float valve positioned in a separate heat insulated compartment, and a third restrictor -which controls the flow of gaseous refrigerant throughA the conduit connecting the secondary evaporator with the low side of sai second compressor.
4. The refrigeration apparatus as claimed in claimv3 wherein said third restrictor is adjustable so that the temperature and pressure in the secondary evaporator can be regulated.
EDWARD P. KELLIE.
REFERENCES CITED The following references are of record in the le of this patent:
UNITED STATES PATENTS Number Name Date 1,718,312 Shipley June 25, 1929 2,024,323 Wyld Dec. 17, 1935 2,277,647 Jones Mar. 24, 1942