US1656917A - Refrigeration - Google Patents

Description

Jan. 24, 1928,-

BY @fm ATTORNEY Paieniai Jan. 24, 192s.

UNITED STATES ANDREW A. KUCBIER, OF CHESTER, PENNSYLVANIA.

nnrmennafrion.

Application led April 7, 1922. Serial-Ito. 550,445.

This invention relates to the art of refrigeration 'and particularly to this art as practiced by means of the so-c'alled compression process. An object of my invention is to provide for a process of the character designated a novel working fluid which shall have as constituents a refrigerant and a lubricant admixing therewith to form a homogeneous fluid of such a character that l0 the lubricant is not mechanically segregated from the refrigerant in passing through a compression refrigeration cycle. l

My invention has for a further object to provide, in a process of the character designed, a novel method and means for lubrieating the compression 'mechanism which shall be effective during long periods of servicewitliout attention and without the necessity of employing separating mechanism for freeing the refrigerant fluidfrom thelubricant.

` A still further object of my invention is to provide a method and means for positively priming the compression mechanism during the initial pumping operations thereof and thereafter to supply continuously adequate quantities of lubricant t0 seal the compression chambers and to lubricate the relatively -moving and contacting surfaces of the compression mechanism.

These and other objects, which will be made apparent throughout the further description of the invention, may be attained by the employment ofthe apparatus hereinafter described and illustrated in the accompanying drawing in which Fig. 1 is a view in longitudinal section illustrating a compression refrigerator in which my invention may be practiced; and Fig. 2 is a view in transverse section through the pump of apparatus shown in Fig. 1.

Compression refrigerators nominally comprise a chamber in which a workingfluid'is evaporated at a relatively low pressure and temperature, a chamber in which the vapors are condensed at a higher pressure and temperature, a compression mechanism for translating the vapors from the evaporation chamber to the condensing chamber, and a valved conduit for returning the condensed fluid at a reduced pressure into the evaporation chamber. The cycle is continuous during any period of operation, heat being absorbed from the `medium surrounding the "3 evaporation chamber to secure the .desired refrigei'ating effect, which heat is removed from the apparatus by bringing an outside f medium into heat-exchanging relation to the contents of the condensing chamber. Apparatus of this character generally operates intermittently; forexample, aperiod of operation of from one to one and a quarter hours being followed by a period of inactivity of from one and a half to two hours, the length of the periods depending upon the dutyy imposed upon the refrigerator and upon the .setting of the automatic devices which control the starting and stoppingiof the compression mechanism.

In general, the compression mechanism is tightly encased to prevent escape .of the working fluid and, for this reason, some,

means for the lubrication thereof must be provided which will operate without attention continuously `and reliably for long periods of time, as for example, for one or more years. It is to this problem of effectively lubricating enclosed compression mechanism of compression refrigerators of the type above indicated that the present invention relates.

It has heretofore been proposed to employ in compression refrigerators a lubricant which is immiscible with the refrigerant. Many liquids possessing to a greater or less extent this property have been used, generally with incomplete success, since no combination of refrigerant and lubricant has been found in which the liquids do not mingle to some 'extent whenibrought together under the conditions of agitation obtaining in a compression refrigerator. Mechanical separators of various types have been employed in connection with machines of this character to facilitate the segregation of the lubricant and the refrigerant. ent has improved the operation but has not resulted in accomplishing sufficiently coinplete segregation of the fluids to enable compression refrigerators utilizing a compound working fluid of this character to operate for long periods without a replacement of the lubricant.

The purpose of the present invention is to provide a thoroughly satisfactory and reliable lubrication of the compression mechanism of a compression refrigerator. fn ac complishing this result, lf have departed radi cally from the prior attempts to employ an immiscible lubricant. l have discovered that by the employment of a working fluid comprising a refrigerant and a lubricant This expedillO which readily mix one with the other to form a homogeneous liquid or physical solution of a character that its constituents are mechanically inseparable, I am enabled to overcome completely the lubrication difli culties heretofore experienced in the operation of compression refrlgerators. y

The term mechanically inseparable as i used in the specification' and yclaims of this application is to be understood to include such admixtures of a refrigerant and a lubricant as do not separatel out into segregated bodies or globules under the influence of gravity or of centrifugal action obtaining in a compression refrigerator. In common With admixturesand solutions of this character, a vaporization of one or both of the constituentsof vmy compound working fluid may be effected by temperature or pressure changes thereof. The working fluid vmay thus bel considered to consist of a very intimate admixture or a physical solution of its constituent parts. y

In obtaining a working fluid of this character, a wide range of refrigerante and lubricants may be employed. I have found by experiment that ethyl chloride as a refrigerant and a mineral oil as a lubricant, which will -readily mix in suitable proportions with ethyl chloride, very satisfactorily meet the required conditions for efficient refrigeration and lubrication. Good results have been obtained ,with a mixture of one part ethyl chloride to one or less parts of mineral oil. The amount of lubricantrequired depends upon the type ofthe pump employed and upon the character .of the 1ubricant utilized. One example of a lubricant which may be satisfactorily employed is a filtered mineral oil having a viscosity of about 750 seconds at 4100 degrees Fahrenheit, Saybolt universal viscometer, and apour test of about zero degrees Fahrenheit, An oil lof such a character may be mixed with ethyl ychloride in an approximate ratio of four parts of ethyl" chloride to one part ofoil.

This admixture has been found under severe centrifugal tests to exhibit no tendencies to separate into it'sconstituents and'h/ence may be'said to constitute a true physical solution. A further example of refrigerant and lubricant constituents, which may form the worlc ing fluid of the present invention, comprises .provide a novel method and apparatus for ensuring a. Sucient lubricant supply te itheJ is drawn into the-pumping mechanism upon the initial movements thereof, effecting a thorough priming. Small quantities of the working liquid are continuously introduced into the stream of vapors flowing to the compression mechanism and pass through the Working chambers with the vapors, seal- -ing the chambers against leakage and lubricating all the Wearingl surfaces.

I show in the accompanying drawings a compression refrigerator in which my novel method ofvoperation may be carried out. It isto be understood that this invention may be practiced in other types of compression machines and that the apparatus illustrated and herein described is employed by way of example and as an aid in presenting a clear exposition of my invention.

In the drawings, 10 designates a- 'condensing chamber, below which is suspended an evaporation chamber 11x A vapor conduit 12 leads from the evaporation chamber into the condensing chamber, and a return pipe `13 serves to convey the condensed fluid to andfrom` the condensing chamber 10 into the evaporation chamber 11; Interposed in the vapor conduit 12 and return pipe 13 is a compression mechanism 14, which maybe of well known type, and driven by a motor 15 of suitable construction. A pressure reducing valve 16, controlled by a float 17is also interposed `in the return pipe 18. The above are the usual elements of a compression refrigerator which may in the practice of my invention be associated in a wide variety of arrangements.

As illustrated in the drawing, the condensing chamber 10 comprises a bell or dome 20 secured to a base plate 21, as by bolts 22. The base plate has formed integrally therewith a depending iange 23 upon which the machine is supported. The motor 15.L is housed within a casing 24,'which as shown is an inverted cup-'shaped casting secured tothe base plaie '21. Mounted upon the casing 2L is a pump housing'25. servesboth theJ motor and the pump, the

lower end of the'shaft being secured in' a suitable bearing inithe base plate 21 .and an intermediate portion of the shaft in a journal bearing provided in top wall 27 of the casing 24. The wall 27 also forms the bottom wall of the 'pump housing and consequently no bearing for the upper end of the shaft 26 is required.

The pump illustrated\is of the type disclosed in my copending application, serially numbered 50.97672fi'1d Octobri 19.2.1, and

A comnion shaft 2.64

v10al tal some1? closely `iits vthe cylindrical bore of thel housing 25 and is provided with oppositelydisposed longitudinally offset ports '36 and 37 that communicate respectively, with the grooves 33 and 34. A rotor or drum 38 is mounted upon the shaft 26, the rotor Aand shaft being eccentric with respect to the bore -of the cyli'ndrical'housing 25..` Radial slots 39 `in the rotor '33 are adapted to receive slidable vanes 40 and 41,' which divide the space formed by the eccentricity of the rotor 38 and the cylindrical shell 35 into chambers 43 and 44, The v`ane 40 is flexibly `keyed tothe cylindrical: shellI 35, as by a pin 45. Rods 46 extend through openings 47 in the rotor and openings 47 in the shaft into proximate relation to the inner edge of vanes 40 and 41. Springs 48 surround the ,rods and exert outward pressure against the The upper and lower surfaces of the rotor vanes and of the cylindrical shell lie in two lparallel planes, the lower surfaces seating against the top wall of the casing24 andthe upper surfaces seating against a disc or plate 50 which is' free to rotate. The' plate 50 is normally held in position by the pressure of the fluid in the chamber 20 but may have a pin 52 engaging the. disc 50 at its central point and pressed to its seat by a spring 53s AThe shaft within the motor housing and above the motor has secured thereto a cup 56, which serves to catch the lubricant which 'works downwardly along the shaft from the pumphdusing` lThe rapid rotation of t-he cup throws .the liquid collecting therein .to the side of the casing, whence it'ows to the bottom thereof and serves to lubricate the bearing.- A vent port 57 opening into the vapor tube 1'2 permits ,the excess liquid to be carried therethrough, into the pump.-

Condensing coils 60 are arranged in the upper part of the dome 2O and are provided with inlet and outlet connections 61 and 62, which pass without the chamber 10 through the base plate 20. An electric cable'63 for furnishing current to the' motor is also passed through-a uid tight plug 64 in the base plate 21. v

The evaporation chamber 11, as shown, comprises a cylindrical tank, having a specially' formed top or cap member 70. The vapor conduit.. 12 and the return' pipe 13, enter the chamber 11 through the cap 70. The p ipe 13 is shown within the conduit 12, an arrangement ,which reduces the number of seals necessary in. connecting the condensi "ing and evaporating chambers; It is to be understood, however, that these conduits may be independent one 'of the other and, that the invention is in no waydependent upon the larrangement of these connections. The conduit 12 opens into a small chamber 72, in the-cap member 70, from which an extension of the vapor conduit 73 depends,

preferably .in the form of any reverse flow passage such as a U-tube. rEhe U-tube should extend downwardly well below the surface o-fl the'liquid andits free open end should terminate near the top of the evaporator chamber, for the. reception of vapors. A small aperture 74 in the curved portions of the U-tube, below. 'the'vnormal level ofthe liquid contents of the evaporation chamber permits someof the liquid to enterthe vapor conduit for the purpose of carrying the lubricant to the ypump a's more fully hereinafter appears. y

The operation of the apparatus thus described is as follows.' The condensing chamber and the evaporation chamber are both filled to a level, such as indicated inl the drawings, with a working fluid consisting 4of a'suitably mixed refrigerant and lubricant; Prior to starting the motor, a quantit of the working liquid fills the U-tube 73 to t e level of the liquid in the chamber 11. The first rotations ofthe pump draw this liquid into the pump so that a thorough priming o f the moving parts is obtained during the initial `operations thereof. The priming liquid not only lubricates the frictionallyv engaging surfaces but seals the working chambers of the/pump againstV vapor leakage. rthe rotation of the pump continues, vapors from the chamber 11 are drawn up los through the conduit 12 into the pump and discharged therefrom into the chamber 20. A fine stream or .spray of the liquid i-n the chamber 11 enters the 'U-tube through the 'aperture 74 and -is commingled with the vapors flowing through the conduit 13 to the pump. y The liquid thus delivered to the pump is sufficient in quantity to effect a thorough lubrication and sealing thereofand i is supplied continuouslyso long as the pump is in operation. When a predetermined cooling action has resulted from the operation of the machine, automatic mechanism y (not shown) cuts olf the current to the motorand .thus stops thepumping action. Durin the period of 'rest which follows, some o the liquid -in the chamber 11 fills the lower portions ofthe U-tube 74, placing the ,mechanism in readiness for starting again.

The `lubrication of the bearings of the shaft 26 is accomplished 'from the liquid delivered to the pump. Some' of this liquid seeps down through the journal bearing in the wall 27 into the cup 56, thence it is thrown by centrifugal force to the side of the motor housing andf collects in the bottom the lower bearing of shafty 26, the excess being carried away through the vent 57 into` the vapor conduit.

iVhile I have shown my invention in but l one form, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various Vother changes and modifi-v cations, Without departing from the spirit thereof and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the'appended claims.

` What I claim is: i

1. In the process of refrigeration in which a liquid is evaporated in one chamber, the vapors pumped into another chamber and condensed therein at a higher pressure, and then returned to they first Ychamber at areduced pressure, the method of lubricating the pumping mechanism which comprises employing a working fluid consisting of a refrigerant and a lubricant which forms therewith a mechanically inseparable homogenelous mixture, introducing portions of the Working fluid into the stream of vapors durl ing their passage to the'pumping mechanism l and passing the commmgled working fluid and vapors through the pumping mechanism.

2. In the process of refrigeration in which a liquid is'evaporated in one chamber, lthe vapors pumped into another chamberrand condensed therein at a higher pressure, and then returned to the first chamber at a reduced pressure, the method of lubricating the pumping mechanism which omprises employing a Working fluid consisting of a halogen derivative of thev methane group .and a mineral oil which forms therewith a mechanically inseparable homogeneous mixture, introducing portions of the Worklng fluid into the stream of vapors during their passage to the pumping mechanism andv passing the commingled working fiuid and vapors through the pumping mechanism.

3. In the process of refrigeration in which a liquid is evaporated in one chamber, the vapors pumped into another chamber and condensed therein at a. higher pressure, and

then returned -to the first chamber at a reduced pressure, the method of lubricating theV pumping mechanism .which comprises employing a Working fluid lconsistlng of ethyl chloride and a mineral oil which forms therewith a mechanically inseparable homo? geneous mixture, introduclng portions of" the working fluid into the stream of vapors vduring their passage to the pumping mechanism, and passing the commingled working fluid and vapors through the pumping mechanism. Y

4. In the process of refrigeration in which va liquid is evaporated vin one chamber, the

vapors pumped into another chamber and condensed therein at a higher pressure, and then'returned to thefirst chamber at a reduced pressure, the method of lubricating the pumping mechanism whichV comprises employing a Working' fluid consisting of a Irefrigerant and a lubricant which forms therewith a 'mechanically inseparable homogeneous mixture, collecting a quantity ofthe working fluid in the path of the vapors to the pump when the pump is idle, draw-- ing into the pumping mechanism such collected fluid upon 'starting for priming the pumping mechanism, and thereafter' introducing portions of the working fluid into the stream of vapors during their passage to the pumping mechanism, and passing the commingled working fluid and vapors through the pumping mechanism.

5. In the process of refrigeration in which a liquid is evaporated in one chamber, the vapors pumped into another chamber and condensed therein yat a higher pressure, andA then returned to the first chamber at av reduced pressure, the method yof lubricating the pumping mechanism which comprises employing a working fluid consisting of ethyLhloride and a mineral oil which forms therewith a mechanically inseparable homogeneous mixture, collecting a quantity of the Working fluid in the path of the vapors to the pump when the pump is idle, drawing into the pumping mechanism such collected ,fluid upon starting for priming the pumping mechanism, and thereafter introducing portions of the working fluid into the stream of vapors during their passage to the pumping mechanism, and passing the commingled working fiuid and vapors through the pumping mechanism.

6. In a refrigeration apparatus in which a liquid is evaporated in one chamber, the vapors pumped into another chamber and condensed therein at a higher pressure, then returned to the first chamber at a reduced pressure, the combination with the condensing chamber, of the evaporating chamber, a body of liquid comprising a refrigerant and a lubricant formingftherewith -a mechanically inseparable homogeneous mixture, conduit means for the passage of vapors from the one chamber to the'other. chamber, a pump associated with said' conduit means for effecting the translation of vapors through said conduit, and means for introducing portions of the liquid into said mingled vapors and av liquid is evaporated in one chamber, the vapors pumped into another chamber and condensed therein at -a higher pressure, then returned to the first chamber at a reduced pressure, the combination with the condensing chamber, of the evaporating chamber,

a body of liquidv comprising a refrigerant and a. lubricant forming -therewith a me` chanically inseparable homogeneous liquid, a'

conduit for the passage of vapors from the one chamber to the other chamber, apump associated withsaid conduit for4 eifectmg the translation of vapors through said conduit, said conduit extending into and 4open.- ing adjacent the top of the said one chamber,

and means for introducing portions of liquid inthe sald one chamber into said conduit, at a point intermediate between the vapor inlet and the pum whereby vthe comiquid are drawn through the conduit into the pump and a lubrication of the pump is obtained.

8. In a refrigerating apparatus in which a liquid is evaporated in one chamber, the

' vapors pumped into another chambenand condensed `therein at a higher ressure and then returned tothe iirst .cham er at a reduced pressure, the scombmation with the condensing Y chamber, of the evaporating chamber, a body of liquid comprising a refrigerant and a lubricant forming therewith a homogeneous liquid, conduit means 'for passage of vapor from the one chamber to the other chamber, and a pump associated with said conduit means for effecting a transla' tion of vapors through said conduit means, said conduit means being provided with an inlet Vfor the admission of vapor and a second inlet for the admissionof liquid,I

whereby the commingled vapor and liquid are drawn through the pump 4and lubrication of the pump is eected.

9. 'In a refrigeration apparatus 'in which a liquid is evaporated in one chamber, the vapqrs pumped-into another chamber and condensed therein at a higher pressure, then' returned to the first chamber ata reduced pressure, and in which the liquid employed `consists' of a refrigerant and a lubricant forming therewitlkia mechanically inseparycle homogeneous liquid, a conduit means for the passage of vapors from the one chamber to theV other chamber, va'pump associatedwith said conduit means forfeiecting the translation of vapors through said means, said conduit vmeans `extending into and below any normal operating level of the liquid in said onechamber in return flow formation, the free upper end of the conduit being disposed well above any normal operating level of the Iliquid in the "said one chamber for the .reception ofvapors, and means for introducing portions of liquid in the said one chamber into said conduit means,I whereby the commingled vapors and liquid are drawn through the conduit means intolthe pump and a lubrication of the pump is obtained.

10. In a refrigeration apparatus inyvhich a liquid is evaporated in one chamber, the

vapors pumped into another chamber", and. condensed therein at a higherpressure then returned to the rst chamber at a reduced pressure, and in 'which the liquid employed consists of a refrigerant and a lubricant forming therewith a mechanically inseparable homogeneous liquid, a conduit means for the passage of vapors from the one chamber to the other chamber, and a pump associated with said conduit means for effecting the translation of vapors through said means, said vconduit means 4extending into and below any normal operating level of the. liquid in said one chamber in substantially return How formation, the free upper end of the conduit opening well above v '.the normal operating level of the liquid in the said. one chamber for the reception of vapors, said conduit means further having 'a restricted openingtherein below the said'l normal operating level of the liquid, where by the commingled vapors and liquid are drawn through the conduit into the pump and a lubrication of the pump is obtained.

1l. In a refrigerating machine in which a refrigerant fluid is vaporized, compressed and condensed in a repeating cycle, in combination, a condensing chamber, an eXpansion chamber, a conduit for thefpassageof" refrigerant liquid from the condensing chamber to the expansion chamber, means associated with said conduit for controlling the distribution of liquid between the said chambers, conduit means for the passage of vapors from the expansion to the condensing chamber, a compressor in said conduit means, said conduit means extending into and below any normal working level of the liquid in the expansion chamber in substantially return flow formation, the free upper `end of the conduit opening well above any normal working level of the liquid in the expansion chamber for the reception of -vapors, and means for introducing portions portions of this working Yfluid in a liquid i passing state into the refrigerant valliicj);x and g fluid 'and' the commingled liquid\wor refrgerantvapor through the Working parts of the machine. p

13. In a refrigerating apparatus, the combination of a condenser, an evaporator, means constituting a path for withdrawing Huid from the evaporator and conveying it tothe condenser, and means responsive upon a stoppage of the 110W for accumlat ing a body of liquid in said lWithdravval path, said body of liqui sealing` the path 10 for preventing the backp w of Hui-d from the condenser to the evaporator.

In testimony whereof, I,4 have hereunto subscribed my name this 4th day of April,

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