US2214698A - Refrigeration apparatus and method - Google Patents

Description

p 1 1940- A. HQKELLY 2,214,698

REFRIGERATION APPARATUS AND METHOD Filed April 22, 1939 wmuzsszs: I L INVENTOR 4., 911.0, 8 ANTHONY H. KELLY ATTORN Patented Sept. 10, 1940 UNITED STATES PATENT OFFICE REFRIGERATION APPARATUS AND THOD Pennsylvania Application April 22, 1939, Serial No. 269,337

7 Claims.

My invention relates to refrigeration apparatus and to an improved method of charging refrigeration apparatus with refrigerant and lubricant.

Before a closed refrigerating system is charged it is necessary for several reasons to remove all non-condensable gases such as, for example, air from the refrigerating system. The presence of non-condensable gases may cause excessive head pressures in the high side of the system so that the eiliciency of the system will be impaired and if large amounts of non-condensable gases are present therein the machine mayeven cease to function. Furthermore, non-condensable gases and air in the system may cause oxidation or deterioration of certain parts thereof. Again, the non-condensable gases and air sometimes react with the lubricant or refrigerant to form water or oxides with the result that the water and oxides combine with other chemicals in the system and cause deterioration, oxidation and rusting of parts of the system. In hermetically-sealed systems wherein the motor and compressor are contained within a sealed casing, the presence of non-condensable gases or air may form chemical combinations with the refrigerant and lubricant which deleteriously affect the insulation of the windings of the motor, etc. It is, therefore, necessary to completely evacuate the non-condensable gases from the system before it is placed in the field charged with refrigerant and lubricant.

In the copending application of Anderson and McCloy, Serial No. 156,162, filed July 28, 1937, for Refrigeration apparatus and method, and assigned to the assignee of the present application, an evacuating and charging system is disclosed wherein the refrigeration system is partially auto-evacuated by the operation of the compressor with the high-pressure side of the system open to atmosphere, and wherein a container filled with the exact refrigerant charge is then attached to the system after it has been closed to atmosphere. The liquid refrigerant in the container enters the system and the compressor is operated to remove the remaining non-condensable gases from the system and collect them in said container, which is then removed from the system.

In practicing the Anderson and McCloy invention it was found that improved results were obtained if a restriction of the proper size was disposed between the container and the refrigerating system during operation of the compressor to evacuate the remaining non-condensable gases from the system into the container.

It is, therefore, an object of the invention to provide an accurate initial charge for refrigerating systems and tofacilitate the removal of noncondensable gases therefrom.

It is also an object of the invention to remove non-condensable gases from the system by the operation of the compressor and to thus dispense with independent evacuating apparatus.

It is still another object of the invention to provide an evacuating and charging system for refrigerating units which is particularly adaptable for use in systems in which a hermeticallysealed motor-compressor unit is utilized and which is also particularly adaptable to large production methods where the refrigerating systems are assembled, charged, and tested on conveyors.

It is still another object of the invention to provide apparatus and a method by which a refrigerating system may be charged very accurately by weight rather than by volume and to improve the process of evacuation and charging set forth in the aforesaid Anderson and McCloy application.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 illustrates a compression refrigerating system to which my invention may be applied and also shows, an enlarged view of the charging apparatus utilized in practicing my invention;

Fig. 2 is a sectional view of a portion of the charging apparatus taken on line II--I l'. of Fig. 1;

Fig. 3 is a top plan view of a metal bonnet having a restriction therein which is preferably utilized in practicing my invention; and,

Fig. 4 is a vertical sectional view of the bonnet shown in Fig. 3.

Referring now to the drawing for a more detailed description, numeral ll designates generally a hermetically-sealed motor-compressor unit of a refrigerating system which embodies a compressor 12 driven by a motor [3 both of which 45 are contained in a sealed casing I4 containing a lubricant l5 which is charged into the system through a filler tube IS. The compressor illustrated is of the reciprocating piston type and a lubricant scoop l1 dips into the lubricant l5 and 50 splashes it over the working parts of the motor and the compressor when the compressor operates. The motor I3 includes a rotor 18 and field windings IS, the latter preferably being formed of copper covered with suitable insulation such 55 as cotton, enamel or the like. In operation of the refrigerating system, refrigerant vapor is withdrawn by the compressor l2 from an evaporator 2| through a conduit 22 which opens into the sealed casing M at 23. Refrigerant vapor enters the compressor |2 through a suction port 24 therein. Gas compressed by the compressor I2 is conveyed to a condenser 25 through a conduit 26, wherein the compressed refrigerant is cooled and condensed, cooling being effected by a stream of air circulated over the condenser by a motor-driven fan 21. Condensed refrigerant is then fed through a capillary tube 28 to the evaporator 2|, the capillary tube preferably being disposed in heat exchange relation with the suction conduit 22. After evaporation in the evaporator 2|, the refrigerant cycle is repeated. A

suitable control (not shown) for effecting cycling operation of the refrigerating system to maintain a predetermined evaporator temperature is ordi-" narily provided.

In accordance with my invention, the refrigerating system has substantially all of the noncondensable gases removed therefrom and is initially charged or is completely recharged in the field with refrigerant in the following manner. A conduit'3l branches from the discharge conduit 26 and a container assembly generally indicated at 32 is attached to the conduit 3|. The container assembly comprises a flared joint 33, shown in Figs. 1 and 2 and a small copper bonnet 34 shown in Figs. 2 to 4 inclusive is clamped between the male and female members of the flared joint. The bonnet 34 is provided with an orifice 35 in the middle thereof which is preferably .020" in diameter. It has been found that this orifice diameter is important and that orifice diameters from .015" diameter to .030" diameter are suitable for a system having a volume of l.32 cubic inches in the portion of the discharge conduit 26 between the discharge valve of the compressor (not shown) and the flared joint 33.

' The flared fitting 33 is connected to a handoperated valve 36 through a conduit 31. A conduit 36 including a sight glass 39 connects the hand valve 36 with a container 4| for containing the refrigerant charge. A pressure gauge 42 may be connected to the top of the container 4| and will register the pressures prevailing in the container 4| and the high side of the system generally. Y

After the refrigerating system has been completely dried, preferably by passing dry air therethrough, it is ready for evacuation and charging. At this time the branch conduit 3| is open to the atmosphere and has preferably been used to complete the air drying circuit. The lubricant I5 is first charged into the sealed casing |4 through the filler tube l6, which is then pinched off and sealed. The compressor I2 is then operated and serves two useful functions: first, the compressor evacuates the lowpressure side of the refrigerating system including the interior the hermetically-sealed casing l4, the sucti n conduit 22 and the evaporator 2| and discharges them to atmosphere through conduit 3| which is now open. At least a portion of the capillary tube 28 is also evacuated. Secondly, the lubricant scoop agitates the lubricant I and any occluded non-condensable gases contained within the lubricant are freed therefrom, enter the suction port 24 and are discharged to the atmosphere through the conduit 3| with the remaining non-condensable 'into the container 4|.

gases from the lowside of the system. The compressor I2 is operated in this manner for about five minutes which ordinarily completes auto-evacuation of the low side of the system. Preferably, While the compressor is still operating the container assembly 32, including the bonnet 34, is attached to the branch conduit 3|. The filler valve 36 is closed at this time and the container 4| contains substantially the exact amount of refrigerant by weight for charging the refrigerating system. After the container assembly 32 is attached to the branch conduit 3| the compressor; is stopped and the hand filler valve 36 is opened, whereupon the refrigerant from the container 4| enters the'refrigerating system through pipe 3|. The refrigerant will drain into the system by gravity, or the pressure in the system may be less than the pressure in the container 4| so that refrigerant will also be forced into the system.

The refrigerating system with the container assembly 32 still attached is preferably disposed at this time in a room in which the temperature and humidity are maintained constant, although this is not necessary to practice my invention. The compressor is now aperated for a period of between 35 to 75 minutes during which time the remaining non4condensable gases in the refrigerating system are collected in the. container. The pipe 3| is then pinched off and sealed. The container 4|, valve 36 and the honnet 34 are then used on other units after the container 4| has again been charged with the correct amount of refrigerant by weight.

The orifice 35 serves to retard the passage of the gaseous mixture of non-condensable gases and refrigerant from the refrigerating system However, a suflici'ent amount ofthe gaseous mixture passes into the container 4| during the operation of the compressor |2 to insure a satisfactory percentage of the non-condensable gas present in the system being collected in the bomb. While the restriction is very small, there is apparently suficient disturbance in the highside of the system on each stroke of the compressor to cause an instantaneous difference in pressure between the two sides of the orifice 35, thus draining a small amount of liquid refrigeratant from the container 4| into the refrigerating system on the suction stroke of the compressor and forcing asmall amount of the gaseous mixture of non-condensable gases and refrigerant from the refrigerating system into the container 4| on the discharge stroke.

It has been noted that, in operation of the system during the period after the liquid refrigerant in the container 4| has initially drained into the system, the level of liquid rapidly builds up to a point varying from halfway on the sight glass 39 to some point above the glass. Some bubbles will be noted going up through the liquid, indicating that gas is entering the container 4|. At this time the temperature of the entire container 4| is approximately the same as that of the condenser. Furthermore, liquid refrigerant is collecting on the sides of the container and trickling downwardly to form the collection of liquid noted in the sight glass. After the compressor has operated for some time, the level of liquid refrigerant begins to drop in the sight glass 39 and finally disappears. All that can be seen in the sight glass 39 after this drop-out is a very faint trickle of liquid refrigerant down the sides of the glass. The top of the container l and the container 4| is is now cooler than the bottom and continues to remain cooler until the end of the processing period.

A possible explanation for the operation of the above system during the time that the compressor I2 is operating and non-condensable gases are being collected in the container 4| is as follows: Ordinarily, especially if the volume between the discharge valve of the compressor small, the velocity of the discharge gas entering the container 4| will be relatively high. If the velocity is sufficiently high it may sweep along liquid refrigerant which is being condensed in the container 4| and re- |5 tain a column of liquid refrigerant in the container 4| and the conduit restriction in the container duits 3| and 38 and possibly the container 4|. By placing a restriction between the discharge conduit 26 and the container 4|, the instantaneous velocity of the gas entering the conportions between the container 4| and the bonnet 34 is decreased.

This permits refrigerant to pass downwardly through the orifice 35 on the downstroke of the compressor l2. Furthermore, by disposing a passage between the discharge conduit 26 and the container 4| the condensation of refrigerant in the container 4| is controlled during operation of the compressor I1 and collection of non-condensable gases in the 4| is assured. In other words, when the ambient temperature or humidity surrounding the container 4| rises, there would be a tendency to condense more refrigerant in the container 4| because the partial pressure of the 35 refrigerant will rise much faster than the partial pressure of the non-condensable gases therein, the total pressure, of course, being substantially the same as condensing pressure except for the presence of the restriction 35. If too much refrigerant is condensed in the container 4| it tends to build up therein and not return to the system. The orifice 35 prevents large amounts of refrigerant gas from entering the container 4| and as set forth hereinbefore also facilitates return of liquid refrigerant to the refrigeration system. It appears, therefore, that by utilizing a restriction such as an orifice 35 between the refrigerating system and the container 4| that after the first ten minutes or so of processing, liquid refrigerant will be returned from the container 4| as fast as it is condensed therein.

The broad concept of regulating the rate of condensation in the container 4| is not my invention, but is the invention of Graham S. McCloy and is described and claimed in copending application Serial No. 271,642, filed May 4, 1939, and assigned to the Westinghouse Electric 8: Manufacturing Company, assignee of the present invention. I do not, therefore, claim herein anything described or claimed in said McCloy application.

From the foregoing, it will be apparent that 5 I have provided an improved method and appa- 70 that it is not so ratus for charging refrigerating systems and for removing non-condensable gases therefrom.

While I have shown my invention in but one form, it will be obvious to those skilled in the art limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire,

therefore, that only such limitations shall be.

placed thereupon as are specifically set forth 75 in the appended claims.

What I claim is:

1. In refrigerating apparatus in which a refrigerant is compressed, condensed and vaporized, the combination of a compressor, a condenser, an evaporator, a device for controlling flow of refrigerant between the condenser and the evaporator, a passageway for conveying compressed refrigerant from the compressor to the condenser, said passageway and condenser comprising a highpressure portion of the system,'a container containing a complete initial charge of refrigerant for the system adapted to be connected to the high-pressure portion of the system and so disposed that refrigerant will be transferred into the system, and a fixed restricting device disposed between the high-pressure portion of the system and the container, said container being adapted to collect and retain the non-condensable gases present in the system.

2. In refrigerating apparatus in which a refrigerant is compressed, condensed and vaporized, the combination of a compressor, a condenser, an evaporator, a device for controlling flow of refrigerant between the condenser and the evaporator, a passageway for conveying compressed refrigerant from the compressor to the condenser, said passageway and condenser comprising a high-pressure portion of the system, a container containing a complete initial charge of refrigerant for the system adapted to be connected to the high-pressure portion of the system and so disposed that refrigerant will be transferred into the system, and a restricted orifice disposed between the high-pressure portion of the system and the container, said container being adapted to collect and retain the non-condensable gases present in the system.

3. In refrigerating apparatus in which a refrigerant is compressed, condensed and vaporized, the combination of a compressor, a condenser, an evaporator, a device for controlling flow of refrigerant between the condenser and the evaporator, a passageway for conveying compressed refrigerant from the compressor to the condenser, said passageway and condenser comprising a high-pressure portion of the system, a container containing a complete charge of refrigerant for the system adapted to be connected to the high-pressure portion of the system and so disposed that refrigerant will be transferred into the system, and a fixed restricting orifice providing a relatively short passage disposed between the high-pressure portion of the system and the container, said container being adapted to collect and retain the non-condensable gases present in the system.

4. The method of charging a closed refrigerating system with refrigerant and removing non-condensable gases therefrom, which system includes a compressor, which method comprises connecting a container of refrigerant into the system containing a substantially exact initial quantity of refrigerant to charge the system, effecting a restriction to the flow of fiuids be tween the system and the container, operating the compressor to force said non-condensable gases into the container and transferring said refrigerant from said container into the system.

5. The method of charging a refrigerating system with refrigerant, said system including a compressor and initially containing gases which are non-condensable at ordinary temperatures and which system is divided into high and low pressure sides, which method comprises operating the compressor with the high-pressure side open to the atmosphere to substantially exhaust the non-condensable gases from the lowpressure side, connecting a container in communication with the high-pressure side. of the system, supplying the container with an initial charge of refrigerant suflicient for thesystem, transferring the refrigerant from the container into the system, effecting a restriction to the flow of fluids betweenthe system and the container,-

operating thecompressor to force the remaining non-condensable gases into the container, condensing gaseous refrigerant which enters the container from the system as the compressor operates, retaining non-condensable gases in thecontainer and continuing the operation of the compressor until the system is completely charged with refrigerant and substantially all said remaining non-condensable gases are in the container.

6. The method of charging a refrigerating system with refrigerant, said system including a compressor and initially containing gases which are non-condensable at ordinary temperatures and which system is divided into high and low pressure sides, which method comprises operating the compressor with the high-pressure side open to the atmosphere to substantially exhaust the non-condensable gases from the low-pressure side, connecting a container incommunication with the high-pressure side of the system, supplying the container with a charge of refrigerant sufiicient for the system, transferring the refrigerant from the container into the system, effecting a restriction to the flow of fluids between the system and the container, operating the compressor to force the remaining non-condensable gases into the container, condensing gaseous refrigerant which enters the container from the system as the compressor operates, retaining non-condensable gases in the container and continuing the operation of the compressor until the system is completely charged with refrigerant and substantially all said remaining non-condensable gases are in the container.

7. In refrigerating apparatus in which arefrigerant is compressed, condensed and vaporized, the combination of a compressor, a condenser, an evaporator, a device fe controlling flow of refrigerant between the co ,denser and the evaporator, a passageway for conveyin co pressed refrigerant from the compressor to the condenser, said passageway and condenser comprising a high-pressure portion of the system, a, container containing a complete initial charge of refrigerant for the system adapted to be connected to the high-pressure portion of the system and so disposed. that refrigerant will be transferred into the system,-and a fixed restricting device disposed between the high-pressure portion of the system and the container, said container being adapted to collect and retain the non-condensable gases present in tli system, said restricting device adapted to limit t eamount of refrigerant vapor entering the container, and, 30

therefore, limiting the amount of refrigerant condensed therein.

ANTHONY H. KELLY.

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