US1854318A - Compressor - Google Patents

Description

April 319, 1932. Q M. c. TERRY y fi COMPRESSOR Filed June 1'7. 1929 4 Sheets-Sheet l ATTORNEY M. C. TERRY April 19, 1932.

COMPRES SOR Filed June 1'7. 1929 4 Sheets-Sheet M C Terr q INVENTOR BY a, Ih.M

ATTORN EY April 19, 1932. M c. TERRY p y COMPRESSOR Filed June 17. 1929 4 Shets-Sheet 4 VLC. Tern WITNESS INVENTOR ATTORNEY pression mechanism showing the location of- Patented Apr. 19, 19321 UNITED sTAT'ssYrjATENT {or-Tics MATSON c. TERRY, or PHILADELPHIA, rmrn'sirnvanm, AssreNoB. To wns'rmGHousE ELECTRIC & MANUFACTURING comranY; A CORPORATION or PENNSYLVANIA.

comrimssoiz Application fi led mam-1926: Serial no. 116,620.

' My invention relates to compression mechanisms, particularly to compression mecha-- nlsms for use in compression refrigerators difference. It has for astill further object to provide for a complete sealing-of the relatively moving parts against the leakage of gaseous fluids being compressed and further to provide an arrangement of expansible.

chambers and ports which shall permit the full volumetric capacity of said chambers to be utilized in translating the fiuld,

These and other objects, which will be made apparent throughout the further description of my invention, may be attained by the employment of the apparatus hereinafter'described and illustrated in the accom panying drawings in which:

Fig. 1 is a view, in sectional elevation,

showlng an arrangement of one form of my compression mechanism in a domestic refrigerating machine 4 Fig. 2 is a view, in sectional elevation, of the compression mechanism shown in Fig. 1;

Figs. 3, 4, 5 and 6 aresectional views, taken along thelines III-III, IV--IV, VEV and VI-VI of Fig. 2 respectively, an

Fig. 7 is a view, in elevation, of the com-- the dowel pins.

It is now customary in constructing domestic refrigerating machines of the compression type to employ compressors of the reciprocating type. Such compressors are driven by electric motors of various capacities ranging from A; to H. P. or more and operating at speeds of from 1700 to 17 5O R. P. M. 'In most of these installations, the

compressor is connected to the motor through some speed changing device such as a belt or a reduct on gear whereby the compressor is permittedto operate at a speed much lower than the motor. .Such an arrangement, however, .is undesirable because the speed reducing means creates objectionable operating noises, thev amount of space occupied by the compressor is excessive, the

cost of manufacture of the compressor is comparatively-high, the noises created by the tapping of the valves forming a part of a reciprocating compressor are unavoidable, the necessity, where a belt is employed, of periodically compensating for stretching, as Well. as numerous other reasons. Of still more importance, however, is the fact that when acompressor is connected to its driving motor through belts or gears, it cannot be readily housed within a single hermetically sealed chamber. Such an arrangement is advisable because otherwise astufling box w th its'well known disadvantages is required for preventing leakage of the refrigerant fluid where the motor shaft enters the compressor.

- In order that a compressor of the recipro eating type might be installed complete with its driving motor in a hermetically sealed casing, resort has been made to an arrange.- ment whereby a compressor of the oscillating cylinder type is employed which is capable of operating at high speeds. It is possible to connect; such form of compressor directlyto its driving motor without the use of any speed reducing'mean's, however, the rapidly oscillating compressor is a source of objectionable vibration.

It has been heretofore generally appreciated that all of the foregoing difficulties could be readily overcome by employing a compressor of the rotary type which could be directly connected to its driving motor. However, rotary compressors, as heretofore constructed, have not been capable of pumping against the required pressure differences without entailing excessive leakage losses and consequently operating at relatively lower efiiciencies than reciprocating pumps of the same capacity. I have, therefore, devised a two-stage rotary type pump, which is so constructed that leakage between the rotating parts, friction losses, and thrusts created by unbalanced pressures have been 2 aeeaere reduced to a minimum. Such a form of compressor is extremely compact, can be directly connected to the motor, is relatively inexpensive to manufacture and due to the absence of all inlet and exhaust valves, etc., is comparatively noiseless in operation. I will now refer to the drawings for a complete and thorough description of a compression mechanism arranged in accordance with my invention.

Referring to Fig. 1, I show a refrigerating machine of a type disclosed in my co-pending application, Serial No. 70,118, filed November 19, 1925, entitled Refrigerator, and assigned to the Westinghouse Electric and Manufacturing Company. This form of refrigerator comprises a condensing chamber 10, provided with a plurality of cooling fins 10 and in which is disposed a compression mechanism 11 for compressing the refrigerant vapor. By locating the compression mechanism in the condensing chamber 10,

no stuffing box is required, the vapor entering the condensing chamber through the inlet 12 and the condensate leaving the chamber through the outlet 13. An evaporator 30 and the expansion valve 30, shown diagrams matically, are connected to the condensing chamber as shown. In order to efl'ect condensation of the refri erant vapor in the chamber 10, a motor driven fan 14 is superimposed upon the chamber in order to effect a circulation of air over its outer walls and over the cooling fins. It is obvious from inspection of the drawings, that a compression mechanism consisting of a belt or a gear driven compressor connected to a motor is entirely unsuited for use in a refrigerating machine of the character illustrated. This idea of enclosing the motor and pump in the condensing chamber is disclosed in a co-pending application of Andrew A. Kucher, Serial No. 509,672, filed October 22, 1921, and entitled Refrigerating machine.

The compression mechanism consists of a motor 15 directly connected through shafting 16 to a compressor 17. The motor 15 is located within a fluid tight housing 19 provided with an upper bearing surface 20 for supporting the compressor. The motor housing 19 is also provided with an upwardly extending cylindrical portion 21 which forms a receptacle 22 for supplying a lubricating fluid to the Working parts of the compressor and the motor.

The shafting 16 consists of a compressor shaft25 and a motor shaft 26, the motor shaft 26having a hollow bore 27 which communicates through a passage 28 with the inlet 12. The motor housing 19 is provided with an upper bearing 23 and a lower bearing 24 for retaining the motor shaft. The motor shaft is provided with a tapered'end portion 29 having a key portion 31 which engages a slot provided in the compressor shaft 25 so as to form a coupling. Angularly disposed openings 32 are provided in the tapered end portion of the motor shaft, these holes being arranged to communicate with a passage 33 formed in the upper portion of the motor housing and connecting with the inlet of the compressor. A spiral groove 34 is provided in the motor shaft for effecting lubrication of the upper bearing 23 and an oil catcher 35 is provided, the contents of which are drained'to the interior of the motor shaft by means of a small opening 36.

Referring now to Fig. 2, it will be seen that my compressor is of the rotary, vane,

multi-stage type comprising a first, or lower pressure stage 41 and a second, or higher pressure, stage 42. An intermediate stationary member 43' is interposed between the first and second stages. As shown in Fig. 6, the first stage 41 consists of a cylinder 44 provided with a concentrically bored surface 45. Located in the cylinder 44 is an inlet 46 which communicates at its lower end with the passage 33 of'the motor housing and at its upper end with suction ports 47 provided in the bore of the cylinder. Discharge ports 48- are also located in the cylinder 44, the latter being spaced adjacent to the suction ports 47 Because of the very effective liquid seal maintained in my compressor, the distance intervening between the suction and discharge ports can be made ver small without incurring undue leakage. 0th suction and dischar e ports are preferably made arcuate in shape. The discharge ports 48 communicate with a passage 51 which extends upwardly into the intermediate member wherein it crosses to the opposite side of said member and again rises upwardly to the secend stage of the compressor as shown in Fig. 5. 1

As shown in Fig. 4, the second stage 42 of the compressor, like the first stage, comprises a cylinder 52 provided with a concentrate bore 53. This stage has its inlet port 54 arranged to communicate with the passage 51 while its discharge port55 communicateswith a discharge passage 56 arranged to discharge the refrigerant fluid vertically from the upper portion of the compressor. Like the first stage, the suction and discharge ports are made arcuate in shape and are disposed only sufficient distance apart as is required to maintain the proper seal.

As shown in Fig. 2, superimposed upon the high-pressure stage 42, is an end plate 58 through which passes a plurality of bolts 59 for securing the end plate 58, the first and second cylinders 44and 52 and the intermediate member 43 to the motor housing 19 as well as to each other. In addition, the end plate 58 is axially aligned with respect to the second cylinder 52, the second cylinder 52 is aligned with respect to both the intermediate member 43 and the first stage cylinder44 and the latter is aligned with respect to the motor housing 19 by respective dowel pins 61, 62.

of cylindrical form and is disposed eccentrically within the bore of the cylinder in adirection toward the space intervening between the suction and discharge-ports. Each rotor is provided with a plurality of radial passages 67 in which are disposed respectivevanes 68 engaging the bore of the cylinders through angularly movable tip pieces 69.

The slots are so proportionedas to permit the vanes to easily slide radially inward and outward the full amount as determined by the eccentric disposition of the rotor within the cylinder. One face of each tip piece is shaped so as to conform to the bore of the cylinder while the opposite face is made somewhat semi-cylindrical in form so that it is free to angularly adjust itself in a seat provided in the vane.

The compressor shaft 16is divided into a first stage section 71.and a second stage section 7 2, each section being integrally formed with its respective rotor. The two shaft sections are connected by a suitable coupling 7 3 which may be of the finger type and which permits the rotors of each stage to floatindependently. The shaft sections are carried in an upper bearing 57 provided in the end plate, an intermediate bearing 60 located in the stationary member 43 and a lower bearing 64 provided in the motor housing 19.

Diametral holes 75 are provided in each rotor for spacer pins 76 which are slidable therein. These spacer pins 76 are made of such length as to hold the vanes 68 radially outward from each other a suflicient distance to prevent dislodgment of the sealing pieces 69. However, they are not of sufficient length'to press the vane against the bore of the cylinder during any portion of a revolution.

ing in the respective discharge ports of-both stages, which pressures are maintained in the space intervening between the vane 68 and the radial passage 67 by suitable ducts 7 7 and 78 provided in the surface 20 of the motor housing and in the upper face of the intermediate member 43 respectively. The ducts 77 and 78 connect the discharge passages 51 and 56 with the circular passages 7 9 and 81, respectively, which in turn connect the inner ends of the radial passa es 67 of each rotor to each other and there y, insure that the pressure prevailing behind the vanes is equiv- On the other hand, the vanes are re-' tained against the bore of the cylinders by a fluid pressure equal to the pressures prevailalent tothat prevailing in the respective discharge ports. This circular passage also serves to transfer the fluid from the backof any inwardly moving vane to the back of the outwardly moving vane.

The spacerfp'ins in both the first and second stages are so arranged as to retain the vanes inlongitudinal[alignment at all times. As

will be seen from inspection of Fig. 2, the

pins cooperating with each pair of vanes are spaced equally from the center or the ends of the vanes in order to. prevent the vanes becoming angularly displaced. This is accomplished also in the second stage where, because of its reduced length, only one spacer pin is utilized for one pair of blades and two spacer pins for the other pair, the first spacer pin being disposed centrally in the rotor and the remaining two spacer pins being spaced equally from the first pin. As one vane of each pairmoves radially outward from the shaft coincident with the inward movement "of the othervane, I provide in the rotor of the first stage suitable passages 82 which assist the circular passage 79 to transfer the gas behind the vanes back and forth to opposite sides of the rotor.

The suction ports in both stages are preferably arranged so that they remain in communication successively with the chambers formed by adjacent vanes until such time as the volumetric capacity of these chambers has reached a maximum. In this way, the chambers are completely filled with gas before the compressing process is started.

Lubricating fluid is supplied to the compressor by means of an inverted tube 83 which has its lower end communicating with the receptacle 22'and which is connected at its upper end to the bore of the end plate 58. The section 7 2 of the compressor shaft is provided with a hollow portion 84 for conveying some of the lubricating fluid to the coupling 73. Longitudinal grooves 85, 86 and 87 are groove 89, as shown in Fig. 6, is provided in the surface 20 of'the motor housing 19 and connects the circular groove79 to the hearing 64 for conveying lubricant thereto. Secured to the. end plate 58 is a bafile 88 which is so arranged that any fluid discharged from the passage 56 is impinged thereon and any entrained liquid is deflected downwardly into the lubricating receptacle 22.

The operation of the above embodiment of my invention is as follows:

Assuming the motor 15 to be rotating in a direction indicated by the arrows in Figs.'4 or 6, the compression mechanism-draws refrigeranf vapor from the evaporator 30 of the refrigerating apparatus through the inlot 12 of the condensing chamber (Fig. 1). Refrigerant vapor passes through the passage 28 to the bore 27 of the motor shaft and thence through the openings 32 to the passage 33 after which it enters the suction port 47 of the first stage of the compressor. As my form of-rotary compressor is capable of pumping against extraordinary pressure differences, it may be utilized in refrigerating machines employing any of the well-known refrigerants. The machine illustrated is disclosed in a co-pending application of Andrew A. Kuchers, Serial No. 550,445, filed April 7, 1922 and entitled Refrigeration. In this machine, the working fluid generally employed consists of a mixture of ethyl chloride and mineral oil which together form a homogeneous mixture or physical solution in all proportions. The Kucher application discloses the idea of constantly entraining a small amount of this fluid in a liquid state into the refrigerant vapor passing to the compressor. Accordingly, the refrigerant vapor entering the inlet 12 has entrained therein a small quantity of liquid. As this entrained liquid has lubricating qualities as well as refrigerating qualities, it lubricates the lower motor bearing 2a in its passage toward the inlet of the compressor.

The refrigerant vapor entersthe first-stage suction ports 47 and is discharged to the discharge ports 48 of the first-stage. The compressed vapor then passes through the passage 51 to the inlet port 54 of the secondstage of the compressor from whence it is discharged to the outlet port 55. The vapor is discharged vertically from the compressor through the discharge passage 56 and is deflected against the bafde 88. l have found that when a refrigerating machine of the type disclosed in this application operates in a room of deg. F. with a box temperature of 45 deg. 1 average, a suction pressure of 20 in. mercury, an interstage pressure of approximately atmosphere and a discharge pressure of 15 lbs. gauge are maintained.

It will be noted that inicompressing the, refrigerant vapor, the vanes 68 move radially in and out in their respective rotors. They are retained against the bore of the cylinders 4A and 52 by the discharge pressure prevailing in the ports 48 and 55 respectively. These pressures are conveyed to the backs of the blades by the ducts 77 and 7 8 which communicate respectively with the circular passages 79 aind 81. These passages are so arranged that the vanes in each stage are retained against the bore of their respective cylinders with a pressure which is always a function of the discharge pressure of their associated stage. In this way, the use of all springs is avoided and the vanes are held against the bore of the cylinder with only sufiicient pressure to.- maintain the proper seal. In addition, the volumetric efliciency is not affected as is ordinarily the case with the existing methods which utilize fluid pressure for this purpose. The circular passages 7 9 and 81 are also utilized to permit the conveyance of fluid displaced by the inward movement of one vane to betransferred to the rear of some other vane which is moving outward and thus prevent the vanes from being retained against the bore of the cylinders by an excessive pressure. Because of the large volumetric displacement efl'ected by the relatively long vanes of the first-stage, the diametral passages 82 are utilized to assist the circular passage 79 in transferring the fluid.

As stated heretofore, the refrigerant vapor passing through the compressor has entrained therein some liquid working fluid,

which working fluid has both refrigerating and lubricating qualities. In passing through the compressor, this entrained liquid assists in maintaining the proper oil film between the tips of the vanes and the bore of the cylinders, between the lateral faces of the revolving rotors and their adjacent stationary members and between the suction and discharge ports of each stage. Some of this entrained liquid, however, reaches the discharge port of the second-stage and passes outwardly from the compressor with the compressed refrigerant vapor. Upon being impinged against the bafie 88, this entrained liquid falls downwardly into the receptacle 22. The refrigerant vapor passes outwardly into the condensing chamber 10 wherein is condensed because of the stream of cooling air circulated by the fan 14. The condensate thus created leaves the condensing chamber through the outlet 13 and passes to the evaporator 30.

The liquid accumulating in the receptacle 22 surrounds the compressor and absorbs the heat is sufficient to vaporize off the refrigerant component of the liquid, leaving a body of liquid in the receptacle 22 which is substantially a lubricant. In this way, not only is the heat of the compressor absorbed but incidentally a lubricating fluid is produced by what may be termed a process of distillation. This novel method of producing a lubricating fluid is disclosed in a copending application of Andrew A. Kuchers, SerialNo. 643,364, filed June 4, 1923, and entitled Refrigerator.

The lubricating fluid accumulating in the receptacle 22 is conveyed by the inverted tube 83 and by the discharge pressure prevailing in the condensing chamber to the upper por tion of the end plate 58 from whence a quantity drains downwardly through the hollow portion of the compressor shaft to lubricate the coupling 7 3. The remaining portion drains downwardly through the oil groove 85 and lubricates the upper bearing 57. This lubricant is then deposited upon the upper transverse face of the second-stage rotor 66 and some of it is thrown outward by cenenerated' in its operation. This heat working clearances to parts. As a consequence,

utilized to work against extraordinary pres-' trifugal force and serves to sealthe lateral another portion per-- face of the rotor-While colates downwardly through the various second-stage rotor. Someof'this lubricant .pass'esradially outward-while another 'por-' tion passes. downwardly through the groove 86' and serves to lubricate the intermediate bearing 60 after which it is joined by some of the lubricant passing over the coupling 73 and is depositedupon the upper face of the first-stage -rotor 65 wherein lubrication and scaling is effected in a manner'similar to that which takes place in the. second-stage, the lubricant ultimately reaching the oil groove 31 .and a portion entersthe upper motor bearing 23 from whence it'is discharged into the oil catcher 35 and is thus prevented from being deposited upon-the windings of the motor 15. The remaining portion of the lubricant enters directly into. the suctionport 33 and is carried into the compression mechanism. Excess lubricating fluid accumulating in the oil catcher 35 is drained into .the bore 27 of the motor shaft-through the opening 36 and is carried upwardly into the inlet of the compressor together with the liquid which is already entrained in therefrigerant vapor. Any excess lubricating fluid accumulating in the receptacle 22 overflows into the condensing chamber and commingles with the condensed refrigerant and is conveyed to the evaporator.

It will be apparent from the foregoingdescription that by developing a multi-stage form of vane compressor, I have produced a very eflicient and very capable form of rotary pumping mechanism. By conveying lubricating'fluid to the working parts in the fmanner described, a very effective seal is maintained between all relatively moving the pump can be sure differences, the wear of the moving part is reduced to a minimum, while quiet opera-.

tion is assured. While I have shown'my I ceptible of various changes and pump as embodied in a refrigerating machine in whichthe refrigerant vapor entering the compressor has entrained therein a liquid having lubricating qualities, nevertheless, it is to be understood that my compressor may also be readily employed in machines wherein no such entrainment takes place and wherein sealing and lubrication of the working parts is effected merely by the lulricating fluid passing through the inverted tu e.

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 susmodificathe spirit tions, ,without departing from that only thereof, and I desire, therefore,

the'lower face of the such limitations shall be placed thereupon asare imposed-by the prior art or as are specifically set forth in the appended claims. What I- claim is:

- 1. In a compression mechanism for elastic fluids,the combination of first and secondstage cylinders, a rotor having transversely slidable vanes fitting each cylinder, an intermediate member for joining the two cylinders and for conveying compressed fluid from the first stage cylinder to the second stage cylinder, means for flexibly coupling the rotors together, and .a shaft for driving the rotors, the shaft including means for supplying fluid to the first stage cylinder.

2. In a compression mechanism for elastic fluids, the combination of first and secondstage cylinders, an intermediate member, an end member, a rotor having transversely slidable vanes disposed in each cylinder, means embodied within the cylinders and the intermediate member for conveying compressed fluid from the first-stage cylinder to the second stage cylinder, the member beingarranged in adjacent end-to-end relation, means for flexibly connecting the rotors together, a shaft for driving the rotors, said the first-stage cylinder.

3. In a compression mechanism for elastic fluids, the combination of first and secondstage cylinders, a rotor disposed in each cylinder, an intermediate member connecting the cylinders, an end member for one cylinder, a motor for driving the rotors, a housing for the motor, a fluid passageway extending through the housing to the first-stage cylinder and means for securing the first and second-stage cylinders, the intermediate memher and the end member to said motor housing.

' 4. In a compression mechanism for elastic fluids, the combination of a motor, a housing for the motor, a first-stage cylinder superimposed upon the motor housing, a fluid passageway extending through the motor housing to the first-stage cylinder, an intermediate member superimposed upon the firststage cylinder, a second-stage cylinder super imposed upon the intermediate member, an end member superimposed upon the secondstage cylinder, and rotors provided in both the first and second-stage cylinders.

5. In a compression mechanism for elastic fluids, the combination of a motor, a housing for the motor, first and second-stage cylinders, an intermediate member connecting the cylinders, rotors driven by the motor and disposed in the respective cylinders, one of said rotorshaving laterally extending journal portions located respectively in the intermediate member and in the motor housing, and bearings for the journal portions em- 6. In a compression mechanism for elastic fluids, the combination of a motor, a hous ing for the motor, first and second-stage cylinders, an intermediate member interposed between the cylinders, an end member for one of the cylinders, rotors driven by the motor and disposed in the respective cylinders, each of said rotors having laterally extending journal portions, one or" the rotors having its journal portions located respectively in the end member and in the intermediate member and the other rotor having its journal portions located respectively in the intermediate member and in the motor housing, bearings for the rotor journal portions provided in the end member, the intermediate member and the motor housing, and a flexible coupling located in the intermediate member for connecting the first and secondstage rotors to each other.

7. In a compression mechanism for elastic fluids, the combination of a cylinder, a rotor disposed in the cylinder and having diametrically opposed slots located in its outer portion, a vane slidable radially in each slot and fitting the cylinder, means connecting the inner ends of all of the slots to each other, and gas passages extending diametrically across the rotor and connecting opposite slots, whereby said connecting means and said openings relieve the elastic fluid displaced by the inwardly moving vanes to the slots of the outwardly moving vanes.

8. In a compression mechanism for elastic fluids, the combination of a cylinder having inlet and discharge ports, a rotor disposed in the cylinder and having diametrically 0pposed recesses provided in its outer portion, vanes slidable radially in the recesses and fitting the cylinder, inflexible slidable spacing members interposed between opposite vanes for preventing abnormal relative movement or said vanes, communicating means for connecting the inner ends of each recess to each other and to the discharge port, and separate communicating means provided between oppositely disposed recesses.

9. in a compression mechanism for elastic fluids, the combination of first and secondstage cylinders, a rotor disposed within and fitting each cylinder, a drive shaft for each rotor, a flexible coupling connecting the drive shafts, and means for conveying lubricating fluid through one of the drive shafts t0 the coupl ng.

l0.' In a compression mechanism for elastic fluids, the combination of first and secondstage cylinders superimposed upon each other, a rotor disposed within and fitting each cylinder, an end member superimposed upon the upper cylinder, means for supplying a lubricating fluid to the end member, and means disposed below the lower cylinder for collecting lubricating fluid drainage.

11. In a compression mechanism for, elastic fluids, the combination of first and secondstage cylinders disposed in adjacent end-toend relation, a rotor disposed within and fitting each cylinder, an end member for one of the cylinders, means for supplying a lubrieating fluid to the end member, means for distributing a portion of said lubricating 'fiuid to one cylinder and its rotor and for conveying the lubricant escaping from said cylinder and rotor to the remaining cylinder and rotor, and means for conveying another portion of the lubricant supply directly to the last-mentioned cylinder and rotor.

12. In a compression mechanism for elastic fluids, the combination of high and low pres sure cylinders arranged in adjacent end-toend relation, a rotor disposed within and fitting each cylinder, an intermediate member for connecting the cylinders, a coupling located within the intermediate member for connecting the rotors, an end member for one of the cylinders, means for supplying a lubricating fluid to said end member, means for conveying a portion of the lubricating fluid from the end member directly to the coupling and thenceto one of the cylinders and rotors, and means for conveying another portion of the lubricant supply from the end member to the remaining cylinder and rotor.

13. In a compression mechanism for elastic it fluids, the combination or" first and second stage cylinders disposed in adjacent end-toend relation, a rotor disposed within and fitting each cylinder, bearings provided on opposite sides of each rotor, means for supplying lubricant to the bearings associated with one rotor and for conveying the lubricant discharged from said rotorto the bearings of the remaining rotor, and means for conveying lubricant directly to the bearings of the last-mentioned rotor.

i l. lln a compression mechanism for elastic fluids, the combination of first and secondstage cylinders superimposed upon each other, a rotor disposed Within and fitting each cylinder, an intermediate member for connecting the cylinders, an end member for the upper cylinder, a lubricant receptaclev surrounding the cylinders, a conduit for conveying lubricant from the receptacle to the' pressure compressor, and meansjior discharging elastic fluid from the high-pressure compressor over said chamber in order that lubricant carried by the compressed elastic fluid may be deposited therein.

16. In a compression mechanism for elastic fluids, the combination of a motor, a housing for the motor, first and second-stage cylinders, an intermediate member interposed between the cylinders, an end member for one of the cylinders, rotors driven by the motor and disposed in the respective cylinders, each of said rotors having laterally extending journal portions, one or the rotors having its journal portions located respectively in the end member and in the intermediate member and the other rotor having its journal portions located respectively in the intermediate member and in the motor housing, and bearings for the rotor journal portions provided in the end member, the intermediate member and the motor housing.

17. In a compression mechanism for elastic fluid, the combination of a cylinder having inlet and discharge ports, a rotor disposed in the cylinder and having diametrically-opposed recesses provided in its outer portion, vanes slidable radially in the recesses and fitting the cylinder, inflexible spacing members interposed between opposite vanes for pre venting abnormal relative movement of said vanes, communicating means for connecting the inner ends of all of the recesses to each other, and separate communicating means provided between oppositely disposed reccsses.

18. in a compression mechanism for elastic fluids, the combination of first and scoop dstage cylinders disposed in end-to-end relation, a rotor disposed within and fitting each cylinder, an end member provided for one of the cylinders, means for supplying fluid to the end member for lubricating both the first and second-stage cylinders and their ass'ociated rotors, and means for collecting lubri-- cant discharged from the cylinder remotely disposed from the end member.

19. in a compression mechanism for elastic fluids, the combination of first and secondstage cylinders disposed in axial relation, a

rotor disposed within and fitting each cylinder, an intermediate member for connecting the cylinders, an end member for one of the cylinders, an encased motor for driving the rotors, a lubricant receptacle surrounding the the second stage compressor for conveying lubricant from the chamber to the workcylinders and supported on the motor casing,

a conduit for conveying lubricant from the receptacle to the end member, and means for conveying lubricant from the end member to both the first and second-stage cylinders.

20. In a compression mechanism for elastic fluids, the combination of first and secondstage compressors of the rotary type, a lubricant supply chamber communicating with the discharge of the second-stage compressor,

means subject to the discharge pressure of

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