US2418962A

US2418962A - Oil separator in refrigeration systems

Info

Publication number: US2418962A
Application number: US597742A
Authority: US
Inventors: Joseph R Zwickl
Original assignee: Worthington Pump and Machinery Corp
Current assignee: Worthington Pump and Machinery Corp
Priority date: 1945-06-06
Filing date: 1945-06-06
Publication date: 1947-04-15
Anticipated expiration: 1964-04-15

Description

April 15, 1947; J. R. ZWICKL 2,413,962

OIL SEPARA TOR IN A REFRIGERATION SYSTEM I Filed June 6, 1945 ATTORNEY Patented Apr. 15, 1947 Joseph a. Zwickl, East Orange, N. 1., assignor to V Worthington Pump and Machinery Corporation, Harrison, N. 1., a corporation of Delaware Application June 6, 1945, No. 597,742

' a 7 Claims.

This invention relates to refrigerating syst .of the closed circuit type utilizing a compressor, condenser, and evaporator or cooler, and in which system a refrigerant such as those of the well known Freon types is compressed, condensed, and evaporated to provide the refrigeration or cooling of the medium to be cooled.

- In such systems,.lubricating oil lost by the compressor is picked up by the refrigerant liquid, and accumulation of such oil in the refrigerating fluid impairs the efliciency of the heat transfer in the evaporator or cooler, resulting in a lowering of the eiliciency of the system. a

It is an object of the present invention to provide means for removing or separating such oil out of the refrigerant fluid and returning the oil to the compressor or compressors for re-use as a lubricant. V a

In such systems employing a number of compressors, each compressor loses a difierent amount of oil, and, consequently, the demands for returned oil of the different compressors vary; therefore, it is another object ofthe present invention to provide means whereby the quantity of the re-claimed or released oil delivered to the respective compressors is controlled by the quantity of oil in the compressor which is available for lubricating purposes.

With these and other objects in view, as may appear from the accompanying drawing, the invention consists of various features of eonstruction and combination of parts, which will be first described in connection with the accompanying drawing showing a refrigerating system of the preferred form in diagram with parts in section and partly in diagrammatic elevation, and the features forming the invention will be specifi-' cally pointed out in the claims.

Referring more particularly to the drawing, the improved refrigerating system includes an evaporator l of any approved type in which the refrigerant is evaporated to provide refrigeration for cooling the medium to be cooled which, as is usual in refrigerating systems,'jis circulated I through the evaporator. 'The vaporous refrigerant passes from theevaporator to the compressor or compressors. In the drawing, two

. such compressors 2 and 3 are shown, but it is to be understood that any number of compressors may be employed withoutvdeparting, from the,

spirit of the present invention and that these compressors may be of the reciprocating type as shown, or of a well known centrifugal type. The vaporized refrigerant which flows from the evaporator I through the line 4 into the suctions 5' of the compressors is compressed and returns from the discharges 6 of the compressors through a suitable line 1 to the condenser 8.

During the operation of the apparatus, oil is lost by the compressors and finds its'way through the system into the liquid "refrigerant in the evaporator I. Such oil must be; removed so as to prevent any excessive oil accumulation within the sysetem which would impair the efliciency of the heat transfer in the evaporator or cooler, and it is desirable to return such oil to the compressor or compressors.

The oil and non-evaporated refrigerant in the evaporator or cooler I fallsto the lowest part of .the evaporator and into a well or compartment indicated at 9, although the well or compartment 9 may be eliminated if desired, and the contaminated liquid refrigerant may be allowed to collect in the lowermost portion of the evaporator or cooler i1 Y From the deepest point of the evaporator or cooler i, which in the drawing is shown as the well 9, a small stream of the liquid, that is, the refrigerant and oil, is drained through a suitable pipe or conduit ill in which is 10 ted a solenoid operated valve II and a needle alve l2. The liquid withdrawn from the even ator I through the pipe I0 is delivered into tlif annular upper chamber iii of the oil separatogf structure M. A pipe coil I 5 is located in the upper annular chamber l3, and it has connection through a suitable pipe IS with the discharge pipe 1 from the compressors 7! and 3 to the condenser 8 for receiving hot discharge gas from the point in the system where the temperature of the gas is highest. The sensible and latent heat of the high pressure'gas delivered to the coil I5 is given off as the gas condenses in the coil l5 during the heating of the liquid delivered to the annular chamber I 3 through the pipe Ill. The condensate from the lowermost part of the coil [5 is returned through a suitable pipe connection I! either to the main cooler or evaporator i, or to any other suitable point in the system whereinthe pressure is less than the pressure in the condenser 8.

The liquid refrigerant whichlis contaminated with oillenters the annular chamber I 3 at the l3 into the main suction line l from the evaporator to the compressors. As more and more of the refrigerant is vaporized and returned as a gas or vapor to the main suction line 4, the oil concentration in the residue of liquid rises steadily and its temperature increases. As the oil rises in the annular chamber |3, it reaches the overflow opening l9 through which it flows over the weir 20 into the oil storage compartment 2|. A temperature bulb 22 extends into the oil separator l4 and it is positioned so that the oil flowing through the opening l9 and over the weir 20 must contact the temperature bulb.

The temperature bulb 22 is of the usual type of thermostat bulb which when subjectedto a predetermined temperature degree will operate the thermostat 23 of any approved construction to close the electrical circuit of the solenoid 24 of the solenoid valve l|, opening the valve and allowing the liquid to flow from the evaporator l into the annular chamber l3. The rate of flow of the liquid into the annular chamber I3 is regulated by means of the needle valve l2. At such time that the temperature oi liquid in contact with the bulb 22, is below a predetermined derequired by it, the solenoid valves 29 are pro-- vided. The solenoids 33 of these valves 28 are connected in the electrical circuit with the floatactuated switches 3|.

When the oil level in any one of the compressors falls to a predetermined level, that is, to a point where the compressor needs an additional supply of oil, its switch 3| will be closed which will cause energization of the motor 32 and the starting of the pump 28. At the same time, the solenoid 33 of the valve 29, which is in the supply line 28 to the compressor needing oil, will be energized which will open the valve and. allow oil to flow into that compressor until such time as the level of oil in the compressor reaches a height to open the switch 3| and break the electrical circuit through the motor 32 and the solenoid 33. If the other compressor in the systemdoes not need oil at the same time as the closing of the electrical circuit of the motor 32 by another of the compressors, its solenoid-actuated valve will remain closed which will prevent the delivery of oil to gree, due to the presence of too much liquid refrigerant in the mixture the thermostat 23 operates to close the solenoid-actuated valve II.

If the flow of the liquid refrigerant, contami-,

nated with oil, to the chamber I3 is too fast, insuflicient refrigerant will be vaporized in the chamber I3 and the temperature of the mixed oil and refrigerant will fall, insufllciently heating the bulb 22 to cause operation of the thermostat 23 and thus stopping the flow to the annular chamber |3 by the closing of the solenoid valve However, when the heat supplied from the coil |5 causes the liquid refrigerant to vaporize and consequently a temperature rise, the bulb 22 will again operate the thermostat 23 and energize the solenoid 24 for opening the valve II. If it is so desired, suitable means may be provided for heating the oil receiver or storage member 2| so as to evaporate out any refrigerant which might flow over the weir 20 into this tank, and prevent reabsorption of any refrigerant vapor by the oil.

The tank 2| is provided with suitable inlet 25 to permit amake up supply of oil thereto when necessary. The oil in the storage tank or receiver 2| is utilized as a lubricant in the compressors 2 and 3 and it is drawn from the storage tank by any suitable type of small Dump, preferably a small gear pump indicated at 23 which discharges the oil into the compressor supply line 21; Branch lines 28 lead from the supply line 21 to the compressors 2 and 3, and these supply lines have solenoid actuated valves 29 located therein as well as-check valves 30. The check valves 30 prevent a back flow of oil from the com pressors into the line when the pump 26 is not operating. Float-actuated electric switch structures 3|, of any approved type which may be purchased upon the open market and as shown diagrammatically in the drawing, are connected to the compressors, and, as is usual in this type of float-operated switch, variations in the level of oil in the compressor operate the switches 3| to make orv break an electric circuit through the motor 32 employed to drive the pump 26.

The quantity of oil in the different compressors will not be uniformly varied, that is, one compressor may lose more oil than the other; therefore, to prevent flooding of the compressor and supply to each compressor only the amount ofoil the compressor not needing -oil. Thus oil is delivered to the compressors only as and whe needed thereby.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that they may be widely modified within the invention defined by the claims.

What is claimed is:

1. In a refrigerating system including a compressor and an evaporator and a condenser and wherein a refrigerant is evaporated compressed and condensed to provide refrigeration, an oil separator, means for delivering mixed refrigerant liquid and oil from the evaporator to said separator, and means controlled by the tempera- 4 ture of the mixture of separated oil and residual refrigerant in the separator for controlling the delivery of mixed refrigerant and oil to the separator.

2. In a refrigerating system including a compressor and an evaporator and a condenser and wherein a refrigerant is evaporated compressed and condensed to provide refrigeration, an oil separator, means for delivering mixed refrigerant liquid and oil from the evaporator to said separator, means controlled by the temperature ofseparated oil in the separator for controlling the delivery of mixed refrigerant and oil to the separator, means for delivering oil from the separator to the compressor, and means controlled by variances in the level of the oil in the compressor for controlling the delivery of oil from the separator to the compressor.

3. In a'refrigerating system including a compressor and an evaporator and a condenser and wherein a refrigerant is evaporated compressed and condensed to provide refrigeration, an oil separator, means for delivering mixed refrigerant liquid and oil from the evaporator to said separator, heat exchange means insaid separator for evaporating the refrigerant inthe separatoryto separate the oil therefrom, and means controlled by the temperature of separatedoil in theseparator for 'controlling the deliveryof 'xedarefrigerant and oil to the separator, j

4. In a refrigerating system inclu ga comevaporating the refrigerant in the separator to separate the oil therefrom, means controlled by the temperature of separated oil in the separator for controlling the delivery of mixed refrigerant and oil to the separator, and means for delivering gaseous refrigerant to said heat exchange means from a point in the system where the temperature of the evaporated gas is sufficient that the hot gaseous refrigerant circulating through the heat exchange means will provide heat for evaporation of the refrigerant; in the refrigerant and gas mixture delivered to the separator.

5. In a refrigerating system including a compressor and an evaporator and a condenser and wherein a refrigerant is evaporated compressed and condensed to provide refrigeration, an oil separator, mean for delivering mixed refrigerant liquid and oil from the evaporator to said separator, heat exchange means in said separator for evaporating the refrigerant in the separator to separate the oil therefrom, means for delivering gaseous refrigerant to said heat exchange mean from a point in the system where the temperature of the evaporated gas is sufficient to provide heat for evaporation of the refrigerant in the mixture of refrigerant and oil delivered to the separator, means controlled by the temperature of separated oil in the separator for controlling the delivery of mixed refrigerant and oil to the separator, means for delivering oil from the separator to the compressor, and means con- I trolled by variances in the level of the oil in the compressor for controlling the delivery of oil from the separator to the compressor.

6. In a refrigerating system including a compressor and an evaporator and a condenser and wherein a refrigerant is evaporated compressed and condensed to provide refrigeration, an oil separator, means for delivering mixed refrigerant liquid and oil from the evaporator to said separator, heat exchange means in said separator for separator, an oil storage receptacle for receiving oilfrom said separator, means for delivering oil from the storage receptacle to the compressor,

and means controlled by variances in the level of the quantity of oil in the compressor for controlling the delivery of oil from said receptacle to the compressor.

7. In a refrigerating system including a plurality of compressors; an evaporator and a condenser and wherein a refrigerant i evaporated, compressed and condensed to provide refrigerant; an oil separator; .means for delivering mixed liquid refrigerant and 011 from the evaporator to said oil separator; means for delivering separated out oil from the separator to said compressors; means controlled by the level of oil in each compressor for independently controlling the delivery of oil from the separator to each compressor; and means controlled by the temperature of separated oil in the separator for controlling the delivery of mixed refrigerant and oil to the separator. I

JOSEPH R. ZWICKL.

REFERENCES CITED Number Date 2,246,244 Consley June 17, 1941