US2102345A - Compressor - Google Patents

Description

Dec. 14; 1937. w. w. WISHARTI COMPRESSOR Filed Feb. 9, 1935 3 Sheets-Sheet Iwvardior: illin/Truw wwhnn't @z- @n llm Dec. 14, 1937-. w, w w s 4 2,102,345

' COMPRESSOR Filed Feb. 9, 1955 3 Sheets-Sheet 3- J5 25L 5J5 Imvenfor:

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Patented Dec. 14, 1937 UNITED STATES PATENT OFFICE- COMPRESSOR William W. Wishart, Chicago, Ill.

Application February 9, 1935, Serial No. 5,712

9 Claims. (01. 230-140) My invention relates in general to fluid-flow apparatus including pumps and motors and has more particular reference to a rotary device 4 especially well adapted for use in the compres- 5 sion of fluids.

An important object of the invention is to provide a fluid-flow device, more particularly a pump or compressor, of simplified construction and having improved means for preventing leakage from' and in the device and for'adjusting the Another important object is to provide standardized parts from which maybe constructeda compressor having any desired number of cylin- 25 ders or stages, my invention providing for the cylinder device of the character mentioned hav- 35 ing aseparate inlet for each cylinder and a common discharge from the device.

Another important object is to provide a multicylinder compressor, the cylinders of which are adapted toreceive the work medium at different 40 pressures attheir respective inletsand to deliver the work medium atthe same pressure at their outlets. 1

Another important object is to provide an hydraulic or fluid-forcing device having facilities 45 for lubricating the operating parts, including a built-in lubricant pump; a further'object being to form the pump withln'the casing of the compressor and to arrange for driving the pump and one of the, -co-operating compressor elements 50 from a common shaft within the casing.

Another important object is to provide'a fluidforcing device or compressor includinga built-in lubricant pump within the compressor casing and including an external lubricant system connected 55 to deliver lubricant to the pump and to withdraw lubricant from a remote part of the compressor casing to which the lubricant is or may be circulated by the operation of the pump.

A further object is to drivingly connect the.

lubricant pump on the shaft within the casing 5 whereby to assist in sealing the shaft at its point of emergence.

A still further object is to provide a device of the character described including a cylinder having a radial duct in an end wall thereof 10 and a channel extending axially of the cylinder either through an axle on which the cylinder is carried or through a support on which a piston is mounted within the cylinder, said channel communicating with the duct so that a work medium vmay travel progressively through the channel, duct, and cylinder.

Another object is to provide a device of the charactermentioned having a passageway for a ,working medium, said passageway communicating with the interior of the cylinder and extending thence radially in an end wall of the cylinder and then axially of said cylinder, either in the cylinder axle or in. a piston support extending within the cylinder.

Another important object of the invention is to provide, in fluid-flow apparatus of the character mentioned, wherein fluid is delivered to or from the work chamber through communicating channels, one extending radially in the cylinder Wall and another axially in the piston support, the combination of a seal,car'ried by one of the co-operating elements or its support and lapping on the other and adapted to prevent fluid leakage to or from the channels at their point of communication. v

A further object is to form the seal as a selfseating, self-lappingelement carried by one of the co -operatlng elements on its support and having wiping engagement with the other element 40 at the opening of the communicating channel therein. g

Another important object is to provide an annular seal having eccentric movement with re- .spect to the surface with whichit has sealing engagement.

Numerous other objects, advantages, and inherent functions of the invention will be apparent from the followingdescription, which, taken in connection with the accompanying drawings, dis- Figures2, 3, and 4 are sectional views taken substantially along the lines 2-2, and 3-3 in Figure 1, and line 4-4 in Figure 3, respectively;

Figures 5 and 6 are perspective views illustrating parts of the device;

Figures 7, 8, and 9 are sectional views showing modified arrangements of the apparatus embodying my invention;

Figures 10 and 11 are sectional views taken substantially along the lines ||0 and in Figures 8 and 9 respectively.

To illustrate my invention, I have shown on the drawings a fluid-flow device comprising a rotary machine especially well adapted to func-' tion as a pump or compressor for'a gaseous medium, although it will be obvious that the invention has application in any type of fluid flow apparatus.

Apparatus, embodying my invention, however, is characterized by the novel arrangement of fluid inlet and outlet conduits, including the arrangement of a conduit extending radially in a cylinder wall and communicating with an axially extending channel which may be formed either in the axle of the cylinder or in the axially extending support on which the piston is carried. In the construction wherein the channel extends in the piston support, I have also provided novel means for sealing communicating channels formed in the relatively moving parts, the seal being formed and arranged in such a way as to move relatively and engage a larger surface of the element with which it has scaling. engagement than the contacted area of the seal, whereby the seal continuously laps the surface on which it is seated and thus maintains the sealing surfaces in smooth evenly polished condition.

I also provide improved means for lubricating the operating parts of the apparatus, including the self-lapping seal, said means including a built-in lubricant pump having a fluid-forcing element in co-airial alignment with and mounted ona shaft common to one of the co-operating elements of the compressor.

I haveemployed these improvements for the purpose of illustratingv the invention in' a fluidflow apparatus, which has further novel features, the invention including the provision of a rotary fluid flow device, which can be constructed either as a single or multi-cylinder ,or stage device by merely adding a minimum number of standard parts in the assembly. I

To accomplish the foregoing, I utilize certain novel structural arrangements including not only the particular form of the parts employed but also the co-operation of-said parts with each other as well as with the improvedlubricating means whereby the operating parts of the device are properly lubricated and sealed against leakage.

The device, which I have shown for the purpose 1 of illustrating the invention, comprises co-operatportions I! of the cylinder.

ing elements including cylinder mean's II and piston means 43, which are mounted for relative movement in order to accomplish the hydraulic function of the device. The cylinder and piston means are mounted in a frame or casing l and are preferably mounted for rotation on the frame about relatively eccentric though parallel axes. The piston means comprises one or more cylin-- drical elements l3, which are mounted within cylindrical portions l9 of the cylinder with then.- peripheral surfaces of the piston means in contact with the inner surface, of the cylindrical wall Since the inner diameter of the cylindrical wall portions]! is largerthan the diameter of the piston means I 3, a crescent shaped work spaceor spaces 2| is defined between the cylinder and piston means.

The frame creasing l5 provides a closed hous'i ing in which the elements H and i3 are mounted and the 'work medium is delivered into the work chamber or chambers 2| through a channel 23 extending axially through the piston means l3 and thence radially in a duct 25 formed in the walls defining the cylinder means. The casing l5 preferably comprises co-operating parts one of which provides a base 21, and wall portions 29 forming a preferably cylindrical compartment opened at one end. The casing also includes a member 3|, forming a cover adapted to close the open end of the compartment, said cover being preferably formed as'a substantially circular plate having peripheral portions 33 adapted to cooperate with the edge portions 35 deflning the casing opening. The casing portions 33 and 35 are preferably provided with co-operating tongue and groove means comprising, in the illustrated embodiment, a groove 31 in the portion 33 and a co-operating tongue 39 on the portion 35, so that when mounted the cover 3| is properly aligned with respect to the casing portion 29 by means of the inter-engagement of tongue 39 in the groove 31. w

The casing parts 29 and 3| are designed to pro- .vide a chamber of, size suflicient to receive a single cylinder hydraulic element. Where it is desired to assemble a multi cyli'nder device, I provide means for enlarging the casing l5, said means comprising an annular ring or rings 4| adapted to be assembled between the casing portions 33 and 35, a ring 4| being employed for each additional cylinder in the assembly, said rings being of a width equal to the increase in length imparted to the cylinder means II by the,

addition of a stage. Each ring 3|. is formed on its opposite'faces with tongue and groove means 43 and 45 adapted to co-operate with the tongue and groove means 31 and 33 between which said rings are arranged. Sealing gaskets 41 are also preferably applied at said tongue and groove means for the purpose of sealing the casing. The

cover 3| and the ring or rings 4|, if used in the assembly, are secured on the wall portions 35 of the casing part 29 by any suitable fastening means such as'the studs or bolts 49, said bolts penetrating perforations formed in 'theperipheral portions 33 in the cover and in the annular rings 4| and threading into openings formed in the annular wallportion 35.

The cylinder means comprises a pair of end plates 5|-and 53 arranged in spaced facing rebetween the end plates 5| and 53 and the entire assembly is clampingly secured together in any suitable fashion as by the fastening means 51,,

' comprising co-operating nuts and bolts, said bolts penetrating a circular serlesof spaced perforations formed in alignment circumferentially on the end plates, rings, and partition means in- I, order to clamp the parts together.- In' order to support the co-operating parts II and I3 in opcrating position within the casing I5, I provide an axle 59 for the cylinder means I I, said axle being attached to the end plate so that the axis of the axle is in line with the geometric center of the cylinder, that is to say, the axle 59 is in alignment with the central axes of the cylindrical inner surfaces of the annular rings IS. The axle 59 extends in an extension 6| formed on the cover 3] and is journalled for rotation in bearings 63 and 65 in said extension.

The outer end of the extension 61 is provided with a cover 62 secured in place in any suitable fashion as by the holding studs 64, said cover having a central opening defining the journal 65, through which the axle 59 extends outwardly in position to be operatively associated with a driving device or motor for the purpose of rotating the cylinder means within-the casing.

The end plate 59 of the cylinder means II is journalled in any suitable fashion on the casing walls 29, said walls being preferably formed with an integral sleeve 61 adapted to extend within a central opening formed in the end plate 53. in order to support the plate for rotation on said sleeve. Suitable bearing means 69 is preferably interposed between the end plate and the sleeve 61, on which it is supported.

The piston forming means l3 are mounted on an axle H, which is supported in the frame l5 in position extending within the cylinder means I I through the central opening in the end plate 53, said axle 7| being supported in an opening formed in the sleeve 67, said opening being eccentric with respect to the axis of rotation of the cylinder means. The portions of the shaft H, which extend within .thecylinder means ll, are arranged to support bearings 13 of any suitable or preferred construction by means of which the piston forming means i3 are rotatably carried on the shaft H. "The portion of the shaft H, on which the piston-forming means is carried, is eccentric with the shaft portion supported in the sleeve 5?. The eccentricity of these shaft per.

tions, however, is less than the eccentricity of the axis of the cylinder means with respect to the supported portions of the shaft ll so that by turning the shaft ii in the sleeve, the eccentricity of the piston within the cylinder may be adjusted and. the clearance between the piston and cylinder at their point of peripheral contact accurately adjusted from outside of the casing. The cylinder and piston supports consequently need not be located in the frame or casing with anyparticular degree of accuracy.

In order to provide for the convenient adjustment of the'piston in thecylindeFin the manner just described, the shaft portion extends outwardly of the wall 29 through 9. preferably threaded embossment Tl, theprojectlng end of the shaft.

being also preferably threaded as at I9 to receive a nut 8| by which the shaft may be locked in adjusted' position. The projecting end' of the shaft is formed with a preferably non-circular portion 83 adapted to receive a turning instrument whereby to rotate the shaft in adjusting the same in the sleeve 61. I also provide a removable cover comprising a cap 85 adapted to be threadingly secured upon the embossment T! in order to en-- close and protect the outer end of the shaft 15 and toprevent fluid'from escaping from the casing through the, sleeve 61 and the embossment in which the shaft 75 is carried.

,The arrangement for'adjusting the clearance between cylinder and piston is not, of course,

necessarily restricted. to a device of the form herein illustrated and may, of course, be applied in any rotary device requiring adjustment. Furthermore the invention herein is not necessarily restricted to a fluid forcing device or compressor having the piston adjustment herein illustrated and described. On the contrary, any suitable or convenient means may be utilized for the adjustment mentioned.

In the illustrated means I3 is mounted on the eccentric portion 74 of the shaft 1|, suitable anti-friction bearings 13 being interposed between the shaft portion 14 and each of the pistons. Each piston comprises a cylindrical block as shown in Figure 6 having an axial opening 81, through which the shaft portions 14 extend. It will be understood, of course, that the shaft H used in a single cylinder assembly will be cut ofi and finished at its inner end substantially as shown at 89 and that the length of the portion '14 is dependent upon the number of cylinders in the assembly: In a multicylinder assembly, the shaft portion i4 extends through an opening 9| in the partition means 55 intermediate adjacent cylinders so that the pistons H! of adjacent cylinders are disposed upon opposite sides of the partition 55.

While I have shown my present invention as applied in a rotary compressor in which both the cylinder and piston are rotated in order to de-' liver the work medium through the work space 2|, it will be obvious that the invention may be embodiment, the piston l applied in any arrangement wherein relative movement is imparted to the piston and cylinder means H and I3 in a manner to cause the work space 2| to' circulate relatively around the cylv.inder and, therefore, I do not wish necessarily to 'limit the invention to a device in which both the cylinder and piston means rotate.

I prefer, however, to arrange the parts so that the cylinderat least rotates on its axle 59 while the pistons l3 rotate on the shaft l 5. Where the device is used as a pump or compressor, the axle 59 will be connected for rotation by a prime mover such as an electric motor while the pistons are driven by an operating connection formed between the pistons and the cylinder. To this end, the cylinder assembly carries a blade 89 extending in a substantially radial direction, said blade having its outer edge secured in aligned end plates may be provided with grooves for receiving the opposed ends of the blade. The blade .is thus held tightly by and between the end plates so that leakage of the work medium between theedges of theblade and the contacting surfaces of the end plates'and rings I9 is prevented. The blade also extends snugly through an opening 93 in the partition 55 so that the opposite sides of the plate extend in adjacent cylinders ofthe assembly.

' The blade extends in substantially radial slots 95 formed in the pistons l3 'so that rotation ofthe cylinder by means of a shaft 59 will cause 7 event, since the cylinder means H and piston 'port of each cylinder.

means I3 are mounted for rotation about relatively eccentric axes, the work spaces 21 in each cylinder will, upon rotation of the parts be caused to travel relatively around the circumference of the rings I9. The blade 99, however, travels with the cylinder assembly so that the operation of the parts will result in the development of unequal pressures in the work spaces in each cylinder on opposite sides of the blade 99, depending upon the direction of rotation of the parts. For example, if the parts are rotated'in a counter-clockwise direction, viewing Figure 3, pressure will be relativelyreduced on the left hand side of the blade and will be increased on the right hand the blade. Conversely, if the rotation is clockwise pressure will be reduced on the right hand side of the blade and increased on the left hand side.

The device illustrated is adapted to function as a compressor and tube driven in a clockwise direction, viewing Figure 3. I consequently provide an inlet port 91' opening into the cylinder on the righ hand side of the blade 89. If desired, these ports may be provided with valve means opening inwardly into the cylinder and the ports are connected by means of a duct 99 comprising aligned openings formed in the rings I9 and the partition 55. This duct 99 is connected with the radial duct 25 formed in the end wall of the cylinder' so that the fluid medium introduced through the duct 25 may be delivered to the inlet The inner end of the radial duct 25 is preferably in communication with the channel 23, whichis formed axially in the piston carrying shaft II. This conduit 23 communicates with the duct 25 at the inner end of the shaft II, the end plate I having an opening, I03 opposite the inner end of the shaft. The

duct 23 extends in the shaft lI axially from the inner end of the shaft toward the opposite or projecting end of the shaft and communicates with a chamber I05 formed in the wall portion' 29 at the sleeve 51, which carries the shaft II.

The duct 23 communicates with the chamber I95 through the inlet III and travel thence through the duct I09, the chamber I05 and thence through for the ports to prevent the return of discharged fluid through said ports into the cylinders. To this end, the ports II3'at their outer ends each carry a sleeve-like insert 1 H9 forming a valve seat I 2| for a flap valve I23. -'I'he flap valves for adjacent ports may comprise a single strip of resilient material secured at its mid-point on the partition 55 with the ends of the strip extending. in position to overlie the valve seats I2I. I

alsof-provide a stop I25 for limiting'the opening movement of the flap valves from their reside of.-

spective seats, said stop and the strip forming the ilap'valves being secured on the partition in any suitable manner as by means of the fastening device I21. Y I

If it is desired to use the device as a fluid motor, the fluid medium will be delivered under pressure through the inlet III and delivered to the inlet'ports 91- through the channels I09, 23,,

"vide improved running seal means between-said parts comprising a sleeve I29 fitted into the end of the shaft II and forming an extension of the channel 23, said sleeve projecting at the inner end of the shaft and being threaded or otherwise sealed thereto. The sleeve carries an annular sealing ring I3I on its projecting end, said seal ring comprising a cup-shaped element adapted to contain a sealing gasket I33 for the purpose of sealing the space between the ring and the sleeve. The end of the shaft 'II' is recessed around the sleeve and a spring I35 is mounted in the recess in position to compress the gasket into the seal ring and to yieldingly urge the ring in an axial direction outwardly on the sleeve into wiping'engagement with the face of the end platearound the opening I03. When the cylinder rotates, the n ring I 3| provides a running seal preventing the escape of the work medium at this point.

. It will be noted that the end plate 5| rotates about an axis eccentric with respect to the central axis of the seal ring so that the latter engages an area of the end plate substantially larger to maintain the sealing surfaces in highly polished condition.

Where the device .of my present invention is embodied as a pump or compressor for use in forcing fluid media containing or. comprising a suitable lubricant.'it may not be necessary to provide for lubricating the apparatus other than by utilizing the working medium itself. Where the device is' used in connection with a work medium which does not itself provide lubrication, I prefer to incorporate a lubricating system and to this end have shown a lubricant circulating system built into the device. The lubricating system comprises circulating means namely a pump venient manner as by means of the studs I43,

which hold the parts together and the studs I45, which hold the pump assembly upon a partition I" formed within the extension 6|. tion I41 has an opening defining a, bearing I49 through which the shaft 59 extends and the parti- The partition divides the extension 6| into a compartment ,I5I extending between the cover plate 62 and the partition and a second compartment containing the pump I31 and the anti-friction bearing 63. The cylinder ring I39 and the-end plates I4I form a compression space in which an annular rotor or fluid-forcing element I53 is mounted for operation, said rotor being splined on the shaft 59 and having an outer surface relatively eccentric with respect to the inner surface of the ring I39.

The compartment I5I forms a seal chamber and the facing surfaces of the partition I41 and the end plate are formed with embossments encircling the shaft 59 and adapted to receive sealing devices I52, which are forced apart in position riding on the embossments by means of a spring I54 extending between the sealing devices.

The seal chamber in the forms shown in Figures 1 and 7, comprises a reservoir for a lubricant.

In the embodiment shown in Figure 8, however,v the chamber I5I is connected with the duct 25 and serves as an inlet chamber for the fluid medium, the duct 25 being connected at its inner end through the channel IOI, which extends axially in the shaft 59 and opens laterally of the shaft through a radial bore I 04 into the chamber The chamber is provided with an inlet I02 so that the work medium may be delivered to the cylinders of the compressor along the path provided by the chamber I5I, the port I04, the duct IOI the radial duct 25, and the manifold 99 leading to the inlet ports 91.

With the arrangement shown in Figure 8, I am able to eliminate the duct 23 in the shaft H, the channel I09, and the chamber I05 in the walls of the casing and also the wiping seal I3I and the mounting therefor. I find also that this arrangement, whereby the channel IOI opens in the chamber I5I instead of continuing in the shaft 59 and opening outwardly of the cover 62, affords a simple and less expensive manner of introducing the work medium to the compressor.

In the forms shown in Figures 1 and '1, the lubricant is delivered into the chamber I5I either directly through the pipe I83, as shown in Figure 1, in which event an inlet duct I59 is formed through the partition I41 to convey the lubricant from the chamber I5I to the pump I31, or, as shown in Figure '1, the lubricant may be delivered by the pipe I83 directly to the pump, which in this case is mounted in the compartment I5I the lubricant traveling a duct I60 formed in the partition I41, thence through a duct 'IIiIl in one of I the end plates I4I of the pump I31. Lubricant is discharged from the pump through a duct I62 into the chamber I5I under pressure and enters a longitudinal duct I55 formed in the axle 59 through a radial channel I64.

As an, alternate arrangement, the ducts I62 and IE4 may be omitted and the pump arranged todischarge directly into the duct I55 so that the lubricant need not necessarily be delivered into the chamber I5I. In fact, where the chamber I5I is used, as shown in Figure 8, as an infrom said chamber.

a 5 mounted on the periphery of the rotor adjacent said radial duct and adapted to bear upon the inner surface of the cylinder ring I39, so that,

upon rotation of the element I53 in a counterclockwise direction viewing Figure 2, lubricant will be drawn from the chamber I5I through a duct I59 formed in the partition I41 and oneof the end plates I4I and'discharged into the duct I55.

The lubricant pump is first assembled in the extension'BI and the bearing 53 fitted to the shaft 59. The cover 3I may then be applied to the shaft 59. As the cover studs 49 are tightened, the sleeve or extension BI is drawn onto the bearing 63, which in turn is forced along the shaft 59, the frictional resistance of the parts causing the shaft and cylinder to move toward the right, viewing Figure 1, until the bearings 63 and 69 assume final assembled position. In this way, the cylinder means II is properly positioned within the casing as an incident to the application of the cover 3 I.

When the axle 59 rotates, it turns the element I53 of the lubricant pump, thus drawing the lubricating medium from the chamber I5I and forcing it into the duct I55 in the axle 59. This duct I55 communicates with another lubricant duct IBI formed in the end plate 5I and opening in a chamber I63 formed by relieving the inner face of the end plate around the seal ring so that lubricant under pressure may be delivered behind the seal ring and serves to force the seal into sealing engagement as well as to lubricate the same. The chamber I53 communicates with the axle opening 81 of the adjacent piston so that the bearing 13 may receive adequate lubrication The pistons are provided with ducts I65 extending from the opening 91 to an annular chamber I61 formed in each piston. The opposite side walls of each piston are formed with openings I69 which communicate the chambers I51 with the partition 55 and with the end plates so that lubricant delivered in the annular chambers I61 through the ducts I65 may be applied to the contacting surfaces of the piston and the partition and end plates. If desired, the partition may be provided with openings I1I between the pistons. Each piston is. preferably provided with a duct I13 extending between the opening 81 and the slot 95 to deliver lubricant to the blade 89. Bearing 69 receives its lubrication by seepage of lubricant from the end of the chamber provided by the openings 81 in the pistons and the sleeve-like support 61 contains a duct I15 extending from an end of said chamber to a lubricant outlet I11 formed in the wall 29. I prefer to connect the outlet I11 in any suitable fashion with the chamber I5I in order to complete the circulating system. In the embodiment illustrated, the outlet I11 is connected by means of a pipe I19 to a reservoir I8I in which the lubricant may be cooled.

The reservoir has a suction pipe I83 communi eating with the suction chamber I5I so that when the device is in operation, the lubricant is drawn from the reservoir into the suction chamber I5I and then is delivered under pressure by the forcing pump I31 into the compressor as previously described and then is returned from the compressor' to the reservoir I8I. Some of the lubricant will, of course, escape from the compressor element and enter the casing l5, such lubricant will collect in a sump I85 formed in the bottom of the casing I5 and will drain into the reservoir I 8| through aconnection I81.

-preferably semi-cylindrical bearing blocks I9I.

These bearing blocks have fiat surfaces facing the blade and between which the blade has reciprocating movement during the operation of the device. The bearing blocks also may rock in the recesses I89 in order to permit the blade to tilt relatively with respect to the piston while at the same time maintaining a surface contact with the fiat surfaces of the bearing block. I also provide an extension I93 in one of the recesses behind the bearing block,-said extension I93 being adapted to receive means to yieldingly urge the bearing block at all times toward the blade. This urging meansmay comprise a block I95 adapted to seat in the extension I93 and springs H1 in position to press the block I95 against its associated bearing block I9I. When the piston is driven by the blade, it will be obvious that the leading block I9I will be held in compression'between the blade and-the seat I89, in which said block is mounted. The 'trailing block, however, will not be in compression and it is the function of the pressure means I95 and I91 to maintain the trailing block in snug sealing engagement with the blade 09. Should the device be arranged so that the pistons are driven by an external prime mover, the pressing means I95 and I91 would be arranged in position to cooperate with the leading block, since, if the piston be arranged to drive the cylinder, the trailing block will be in compression between the parts and the leading block will require to be held in contact with the blade 09.

In the devices shown in Figures 1, 7, and 8, the several cylinders of the assembly receive the work medium through the common inlet including the duct 25 and the cylinders discharge into the casing of the device operating as a receiver for the compressed work medium. It is, of course, within the contemplation of my present invention totranspose the intake and outlet ports 91 and. I I3 and drive the working members in the opposite direction, 1. e. in a counter-clockwise direction viewing Figure 3 in order that the work medium may be drawn into the cylinders from the casing and discharged under pressure through for the compressed gases, or by driving the unit' in the opposite direction and making the appropriate changes in the inlet and discharge ports 91 and H3, the device-may be arranged to draw -the work medium into the cylinders from the casing and discharge the same through separate discharge channels.

In Figure 9 of the drawings, I have shown acompressor adapted to function in this fashion; When the compressor cylinders are arranged with common intake and discharge spaces, as shown in Figures 1 and 8, it is usually necessary and preferable-to make the cylinders so that each have the same fluid displacement. However,

several cylinders so that a single unit may be employed to produce a variety of positive or nega- For example, the device of my,

tive pressures. present invention may be utilized to deliver the work medium .at or slightly above. normal atmospheric pressures with the suction side of each cylinder drawing a different degree of subnormal or vacuum pressures. Such a device will have great value in a refrigerating system employing an evaporable medium, such as ammonia, carbon dioxide, ethyl chloride, as the work medium to be delivered by the compressor ina circulating system including evaporators arranged in parallel and connected with the pressure side of the unit. In such a system, the suction side of certain of the evaporators may be connected with the intake to one cylinder of the unit while other evaporators may be connected to the suction intake of another cylinder of the unit so that different evaporator-s of the system may besubjected to different degrees of vacuum pressure. In such an arrangement, the refrigerant will evaporate more vigorously in those evaporators which are connected to the cylinder drawing the higher vacuum and consequently will absorb more heat. Theobvious advantages of a single refrigerating system capable of producing different 'rates of heat absorption are apparent and are made feasible as a practical matter by an apso that the volumetric displacement of one cylinder per revolution of the device is less than that a of the other. It is not, of course, essential to change the volumetric displacement by varying the width of the cylinder since the same may be accomplished by altering the diameter of the parts without'changing the width It is, however, less expensive and simpler'to control the displacement of a cylinder by altering its width only, since this requires only the shaving down of a cylinder of standard diameter while to increase or'decrease the diameter of the cylinder requires the fabrication of non-standard parts '-with the additional expense of patterns'and other manufacturing adjuncts. The pistons 205 and 201 shown in Figure 9 are illustrated in opposed relationship, and the piston supporting shaft will necessarily have a crank-like form. It is, however, entirely within my inventive concept to arrange the pistons in the embodiment of Figure 9 in axial alignment as in the embodiments shown in Figures 1 and 8. Both of the cylinders MI and 203 have outlet ports 2I I corresponding with the ports II3 of the embodiments previously described. These outlet ports vent through valves 2I5, similar to the valves II1, into the casing I5.

Each cylinder also has an' inlet port 2I1 corre-' spending with the ports 91 previously described, but each port 2I1 connects with a separate duct 225 extending radially in the end plate 25I. The

ducts 225 each communicate with a separate channel 221 and 229 extending axiallyin the shaft 59, on which the cylinder assembly II is carried. The cover extension 6| is provided with a removable partition 23l intermediate, the end plate 62 and the partition I41, thus dividing the space between the partition I41 and the cover plate 62 and providing Separate chambers 233 and 235 on opposite sides of the partition 23!. The axle 59 extends through the partitions I", 23I and 62 and is provided with seal means 252 corresponding with the seal means i52 previously described and functioning to seal the shaft against the passage of fiuid from the chambers 233 and 235 along the shaft. The longitudinally extending channels 221 and 229 open respectively in the chambers 233 and 235. The walls of the extension 6i also are provided with intake fittings 30! and 303 opening respectively in the chambers 233 and 235.

During the operation of the device, each cylinder will deliver compressed gases into the housing I at the same pressure but the compression elements 2M and 205 will draw a pressure at the inlet fitting Nil-substantially less than the pressure prevailing at the inlet fitting 303.

The lubricating system for the embodiment illustrated in Figure 9 may be substantially similar to that provided for the embodiment shown in Figure 8. If it is desired to build a compressor having a common inlet or suction and separate discharge outlets for theseveral cylinders, it is simply necessary to transpose the outlet and inlet ports 2 and 2H and drive the device in the opposite direction.

It is thought that the invention and numerous of its attendant advantages will be understood from the foregoing description and it is obvious that numerous changes may bemade in the form, construction, and arrangement of the several parts of the illustrated apparatus without departing from the spirit or scope of my invention or sacrificing any of its attendant advantages the forms herein described being merely for the purpose of illustrating the invention.

Having thus described my invention, what I claim as new and desire to secureby Letters Patent is as follows:

1. A device of the character described comprising cylinder means providing a plurality of pressure stages, piston means associated with each stage,-said cylinder means having a projecting shaft fixed on an end wall thereof whereby the same may be supported for rotation about its axis, axially extending duct means in said shaft, blade means cooperatively associated with the cylinder means and the piston means in the several stages, said cylinder and piston means being operable to develop a pressure differential on opposite sides of the blade means in each of the L stages when the cylinder means is rotated, said end wall carrying the shaft having a plurality of substantially radially. extending ducts communicating each with one of the several stages and with said axially extending duct means.

2. A device as set forth in claim 1, wherein the piston means of the several stages are carried on a common supporting shaft.

3. A device as set forth in claim 1, wherein the shaft includes a lubricant duct communicating with the interior of the cylinder means within the piston means in each stage, and means on said shaft and operatively associated with said lubricant duct to deliver a lubricating medium withinthe several stages of the device.

4, A device of the character described comprising cylinder means providing a plurality of pressure stages, piston means associated with each said cylinder means, ducts in said shaft. each opening laterally thereof, certain of said ducts communicating each with at least one of said stages, a sleeve-like support receiving said shaft,. said support defining a plurality of adjacent chambers through which said shaft extends in position to communicate certain of the lateral openings of said shaft ducts each with at least one of said chambers.

,5. A device as set forth in claim 4, including means for sealing said chambers against leakage along the shaft between adjacent chambers.

6. A pump or compressor comprising a cylinder element including a cylindrical wall and end walls extending substantially normal to the axis of the cylindrical wall, piston means within said cylinder element to define a working space within the cylindrical and normal walls, a shaft fixed on one of said normal walls, radial duct means in one of said normal walls and opening into said work space, said duct means including a plurality of radially extending ducts, said shaft being formed with a plurality of axially extending channels therein, each channel communicating with a corresponding radial duct, the cylindrical wall of the cylinder element comprising a plurality of annular rings in axial alignment and defining separate working spaces within the element, and said piston means comprising a separate piston element in each work space of the assembly, said rings being formed with channels communicating with said radially extending ducts and providing ports communicating with said work spaces. I I

7. A fluid flow device of the character described, comprising a cylinder element providing a plurality 'of rings in end to end relationship, each ring defining a compression space, a piston in each space, said cylinder element comprising an end plate closing an end of one of said rings.

- a shaft fixed on said end plate and extending outwardly of said cylinder means, a sleeve-like support through which said shaft extends and in which the shaft is rotatably supported, means on said sleeve-like support forming a plurality of adjacent chambers therein, longitudinal ducts in said shaft, opening one in each chamber and connecting each with a radial duct formed in said end plate, one of said radial ducts communicating through a channel in the rim of one of said rings with the work spacedefined by said ring, and the other radial duct communicating with another of said work spaces through aligned channels formed in a plurality of said rings.

8. A device of the character described comprising cylinder means providing a plurality of pressure spaces forming stages, piston means in each stage, a blade cooperatively associated with the cylinder means and each of said piston means, whereby to drivingly connect the .piston and cylinder means for rotation about relatively eccentric axes to develop a pressure difference on opposite sides of the blade in each of said stages,

, a drive shaft fixed on said cylinder means for rotatingly supporting and driving the same about its axis, said shaft being connected on an end wall of the cylinder means and having ducts in the shaft communicating, at the cylinder-connected end of the shaft, with radially extending ducts within the end plate, said radially extending ducts communicating at the periphery of said end plate with longitudinally extending ducts formed in the cylindrical portion of said cylinder means, and each of the longitudinal ducts opening through said cylinder means upon one of said pressure spaces adjacent the blade of said space.

9. A device of the character described comprising cylinder means providing a plurality of pressure spaces forming stages, piston means in each stage, blade means cooperatively associated with the cylinder means and each of said piston means whereby to drivingly connect the piston and cylinder mean'sfor rotation'about relatively eccentric axes to develop a pressure diflerence on opposite sides of the blade means in each of said stages, a drive shaft fixed on said cylinder means for rotatingly supporting and driving the same about its a ds, said shaft being connected on an end wall of the cylinder means and having ducts in the shaft communicating, at the cylinder-connected end'of the shaft, with radially extendin ducts within the end plate, said radially extending ducts communicating at the periphery of said end plate with longitudinally extending ducts formed in the rim of said cylinder means and- WILLIAM W. wIsHART.

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