US2214697A - Refrigerating apparatus - Google Patents

Description

p 10, 1940- G. s. M cLoY 2,214,697

- I REFRIGERATING APPARATUS Filed May 4, 1959 WITNESSES: v I 42 hfinv GRAHAM 5. MC40Y INVENTCR ATTORNE 55 in the high pressure side.

Patented Sept. 10, 1940 UNITED STATES 2,214,697 REFRIGERATING APPARATUS Graham S. McCloy,

East Lon'gmeadow, Mass as signor to Westinghouse Electric & Manufacturing Company,

East Pittsburgh, Pa., a. corporation of Pennsylvania Application May 4, 1939, Serial No. 271,642

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 8 it is necessary for several reasonsto 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 pressure side of the system 0 so that the efficiency of the system will be impaired and if large amounts of non-condensable gases are present therein the machine may even cease to function. Furthermore, non-condensable gases and air in. the system may cause oxi-' dation 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 autoevacuated by the operation of the compressor with the high pressure side of the system open to atmosphere, and wherein a container filled with substantially the exa t refrigerant charge is then attached to the syst m after it has been closed to atmosphere. Th liquid refrigerant in the container enters the ystem and the compressor is operated to remove the remaining noncondensable gases from the system and collect' them in said container, which is then removed from the system. In practicing the Anderson and McCloy in- I vention it was found that improved results were obtained if the rate of condensation was controlled or retarded in the container under certain ambient temperature-conditions and with refrigerating systems of varying cubical content It is, therefore, an objectof the invention to provide an accurateinitial charge for refrigerating systems and to facilitate the removal of noncondensable gases therefrom.

It is also anobject of the invention to remove 5 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 ate-hermeticallysealed motor-compressor unit is utilized and which is also particularly adaptable to large pro- 15 duction 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 accurate,- 2

ly by weight rather than by volume and to improve the process of evacuation and charging set forth in the aforesaid Anderson and McCloy application. y

It is a further object of my invention to provide apparatus and a method by which a refrigerating system has the non-condensable gases removed therefrom and is charged by attaching a container filled with substantially the exact initial charge of refrigerant for the. system to the interior of the system, thereafter transferring the charge from the container into the system and the non-condensable gases from the system into the container and regulating the rate of condensation of gaseous refrigerant in the container to effect complete removal of the noncondensable gases from the system and the transfer of substantially all of the initial charge from the container into the system.

These'and other objects are effected by my 40 1 invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a partof this. application, in which the. single figure of the drawing illustrates a compression refrigerating system to which my invention may be applied and also shows. an enlarged view of the charging and non-condensable gas-removing apparatus utilized in practicing my invention.

Referring now to'the drawing for a more detailed description of my invention, numeral ll designates, generally, a hermetically-sealed motor-compressor unit of a refrigerating system which embodies a compressor 12 driven. by a motor l3 both of which are contained in a sealed casing l4 containing a lubricant l5 which is charged into thesystem through a filler tube l6. The compressor illustrated is of the reciprocating piston type and a lubricant scoop l1 dips into the lubricant l5 and splashes it over the working parts of the motor and the compressor when the compressor operates. The motor l3 includes a rotor l8 and field windings 19, the latter preferably being formed of copper covered with suit-,

able insulation such as cotton, enamel vor 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 14 at 23. Refrigerant vapor enters the compressor l2 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 eifected'by a stream of air circulated over the condenser by a motor-driven fan 21. Condensed refrigerant is then fed through a capillary tube 26 to the evaporator 2|, the capillary tube preferably bing 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 ordinarily provided.

In accordance with my invention, the refrigerating system has substantially all the non-condensable gases removed therefrom and is initially charged or is completely recharged in the field with refrigerant in the following manner, the lubricant having been charged .into the system through the filler tube i6 as already described. A conduit 3! branches from the discharge conduit 26 and a' container assembly is generally indicated at 32 and is attached to the conduit 3|.

The container assembly comprises a lower hand valve 33 connected by a conduit 34 to an upper hand valve 35 which is in turn connected to a container 36 through a conduit 3'3. A removable heat insulating cover 38 is disposed around the container 36 for a purposev hereinafter described.v

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. Q

The lubricant i5 is first charged into the sealed casing l4 through filler tube l6, which is then pinched OE and sealed; The compressoris then operated and serves two useful functions: first,

non-condensable gases.

the compressor evacuates the low-pressure side of the system including the hermetically-sealed casing M, the suction conduit 22 and the evaporator 2| and discharges the non-condensable gases therein to atmosphere through the conduit 3i,

which isnow open. At least a portion of the capillary tube 28 is also evacuated. Secondly, the lubricant scoop i1 agitates the lubricant l5 and the non-condensable gases contained within the lubricant is freed therefrom, enters the suction port 26, and are discharged to the atmosphere through the conduit 3 iwith the remaining The compressor I2- is operated in this manner for about five minutes .which ordinarily completes auto-evacuation of the low-pressure side of the system Preferably, while the compressor is still operating, the assembly a2 is attached to the branch conduit 3|. The

hand valve35 is closed at this time and the con-' tainer 36 contains substantially the exact amount of refrigerant charge by weight for the refrigerating system. After the container assembly 32 is attached to the branch conduit 3!, the hand filler valves 33 and 35 are opened, whereupon the re- 5 frigerant from the container 36 enters the refrigerating system through conduits 34, 31 and pipe 3| Refrigerant will drain into the system by gravity, or the pressure in the system may be less than the pressure in the container 36 so that the 10 refrigerant will also be forced into the system.

The compressor is now operated for a period of between 35 to 75 minutes, for example; during which time'the remaining non-condensable gases in the system are collected in the container. 15

Either the pipe 3| may be pinched off or the conduit 34 may be pinched off after the valve 33 isclosed if it is desired to have the hand valve 33 remain with the system for purging or the like. The hand valve 35, conduit 31 and container 36 20 are then attached on other units after the-container 36 has again been charged with the correct amount of refrigerant by weight.

In practicing the aforesaid Anderson and Mc- Cloy invention, it was found that. improved re- .26 sults were obtained at high ambient temperatures or high ambient relative humidities if the container 36 was provided with the heat insulating covering 38. It was also found that the heat inwhen the cubical content of the high pressure side of the refrigerating system is relatively small. The purposeof the heat insulating covering 38 is to retard or control the rate of condensation of refrigerant gas in the container 36. '85 At higher ambienttemperatures or higher ambient relative humidities, the partial pressure of the refrigerant gas in the container 36 is higher so that'the rate of condensation is greaterin the container 36. It is believed ,that due to theincreased condensation rate of the. refrigerant and the gas velocity .through the pipe 3!, the hand valves and the conduit 31, liquid refrigerant sometimes collected in the container 36 and was not returned to the' system until the compressor 45 I2 was stopped. Under these conditions, it was necessary to permit the excess liquid in the container 36 to drain into the system and to shut the valve 35 at exactly the right time to prevent non-condensable gases from returning to the sys-' tem. Such operation took considerable time and was very critical. By adding heat insulation to the container 36, the rate of condensation of the refrigerant gas is reduced in the container and increased in the condenser 25. All of the refrig-" erant liquid in the container 36 is,therefore', returned to the system while the compressor l2 is still operating, thus insuring complete evacuation of the non-condensable gases from the system and complete removal of the condensed refrigerant gas from the container 36 into the re frigerating system. i

In systems of small high side volume, the increase in gas velocity-in the high side apparently retarded the return of refrigerant liquid from the container 36 and reducing the rate of condensation in the container as resulted in all the liquid returning while the compressor I 2 is operating.

My invention relates broadly, to a method and apparatus for evacuating and-charging refrigerating systems by the method set forth in the aforesaid Anderson and McCloy application, wherein the rate of condensation in the container 36 is retarded or controlled. Another method and apparatus of effecting the same 1 result is shown and described in the copending application of Anthony H. Kelly, Serial No.-

- of condensation of refrigerant gas in the container is retarded or controlled so that all of the non-'condensable gases are collected in the c'on-f tainer and all; of the refrigerant charge in the .container is transferred to the system. It is also obvious that I have provided an improved method and apparatus for evacuating and charging refrigerating systems which iseffective over a wide range of ambient temperature conditions.

While I have shown my invention in but one form, it'will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes andv modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is: v

1. The method of evacuating non-condensable gases and charging'a refrigerating system including a compressor and high and low pressure sides, which .method comprises operating the compressor with the high side of the refrigerating system open to atmosphere to substantially evacuate the low side of the system, attaching a container to. the high side of the system, which container is filled with substantially the exact initial ant vapor thus refrigerantcharge for the system, closing the high side of the system, transferring the refrigerant charge from the container to the system, operating the compressor to convey a mixture of refrigerant vapor and non-condensable gases into the container; condensing the refrigerant vapor thus conveyed to the container and returning it in liquid form to the system while retaining the noncondensable" gases in the container and. controlling the rate-of condensation of refrigerant in said container. I

2. The method of evacuating non-condensable gases and charging a refrigerating system including a compressor and high and low pressure sides, which method comprises attaching a container to the high side of the system, which container is filled with substantially the exact initial refrigerant charge for I the system, transferring the refrigerant charge from the container to the systern, operatingthe compressor to convey a mixture of refrigerant vapor and non-condensable gases into the container, condensing the refrigerconveyed to the container and returningitinliquidformtothesystemwhile retaining the non-condensable gases in the container and controlling the rate of condensation of refrigerant. in said container.

3. Inrefrigerating and charging apparatus, the

combination of a refrigerating system containing 5 non-condensable gases and including a compressor, a container filled with substantially the exact initial charge of refrigerant for the system, said container being subjected to the cooling effect of the ambient atmosphere, means for conx necting the container into the system so that when the compressor is operated after the charge from the container has entered the system, a mixture of refrigerant vapor and non-condensable gases enter the container, the refrigerant vapor is condensed and the non-condensable' gases remain in the container and means for retarding the rate of condensation of refrigerant vapor in said container as the ambient temperature rises.

4. In refrigerating and charging apparatus, the

combination of a refrigerating system containing non-condensable gases and including a compressor, a container filled with'substantially the exact initial charge of refrigerant for the system,

said container being subjected to the cooling effect of the ambient atmosphere, means for connecting the container into the system so that when the compressor is operated after the charge. from the container has entered the system, a mixture of refrigerant vapor and'non-condens able gases enter the container, the refrigerant vapor is condensed and the non-'condensable gases remain in the container and means for retarding the rate of condensation of refrigerant vapor in said container as the ambient temperature rises,

said controlling means comprising heat insulation for reducing the transfer of heat from the container to said ambient atmosphere.

5. The method of evacuating non-condensable gases and charging a refrigerating system including a compressor and high and. low pressure sides,

which method comprises operating the compre'ssor with the high side of the refrigerating system open to atmosphere to substantially evacuate the low side of the system, attaching a container to the high pressure side of the system, which container is filled with substantially the exact initial refrigerant charge for the system, closing the high side of the system, transferring the refrigerant charge from the container'to the 50' system,

operating the compressor to convey a mixture of refrigerant vapor-and non-condensable gases-into the container, condensing the refrigerant vapor thus conveyed to the container and returning it in liquid form refrigerant in said container so that more refrigerant is condensed in other portions of the high GRAHAM S. MOCI DY.

to the system while so retaining the non-condensable gases in the container and retarding the rate of condensation of

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