US2504841A

US2504841A - Rotary compressor

Info

Publication number: US2504841A
Application number: US561720A
Authority: US
Inventors: Frederick M Jones
Original assignee: U S THERMO CONTROL CO
Current assignee: U S THERMO CONTROL CO
Priority date: 1944-11-03
Filing date: 1944-11-03
Publication date: 1950-04-18
Anticipated expiration: 1967-04-18

Description

April 18, 1950 F. M. JONES ROTARY COMPRESSOR 5 Sheets-Sheet 1 Filed Nov. 3, 1944 INVENTOR. 5 M. JONES ToRM April 1950 F: M. JONES 2,504,841

ROTARY COMPRESSOR Filed Nov. 3, 1944 5 Sheets-Sheet 2 INVENTOR. FREDERICK M. JONES 'AT TORNEY April 18, 1950 F. M. JONES 2,504,841

ROTARY COMPRESSOR Filed Nov. 3, 1944 5 Shests-Sheet 3 /1 FIG 4 2 ll IO l7 INVENTOR.

, FRE ERICK M. JONES BY M A T'ORNEY April 18, 1950 F. M. JONES ROTARY COMPRESSOR 5 Sheets-Sheet 4 Filed Nov. 3, 1944 l S 2 m N TO. B m Y C2 K E 2% EMF R I E o 6 l 6 mmv. 3 FB ||7 7 F 8 n w 3 a q n N N& II P S a 3 x M x N. m m w m ac u n w m 2 0 B M. m 2

April 18, 1950 A F. M. JONES 2,504,841

ROTARY COMPRESSOR Filed Nov. 3, 1944 5 Sheets-Sheet 5 FIG.7

5 C 33 29 I5 P6 32 S5 c3 s3 SI l5 0 PI 56 3457 2| INVENTOR.

FRE RICK M. JONES AT TORNEY Patented Apr. 18, 1950 ROTARY COMPRESSOR Frederick M. Jones, Minneapolis, Minn., assignor, by mesne assignments, to U. S. Thermo Control 00., Minneapolis, Minn, a corporation of Minnesota Application November 3, 1944, Serial No. 581,720

4 Claims. (Cl. 230-45) My invention relates to improvements in a rotary compressor. In particular it relates to a compressor of relatively small dimension which is provided with means for compressing a fluid in two stages, thus materially increasing the efflciency of operation.

In the field of refrigeration, it is highly desirable to provide a compressor which is relatively small in dimension and yet which is effective to quickly remove the refrigerant in vapor form from an evaporator so as to maintain a condition within the evaporator which is conducive to provide for rapid evaporation of liquid refrigerant. To accomplish this result, the compressor should primarily be an effective evacuator even though the gas pressure in the evaporator is less than the prevailing barometric pressure, and secondly, the compressor should be capable of delivering the vapors to the condensor in a positive manner and under considerable pressure.

While the foregoing features are particularly desirable in refrigeration compressors, they are equally desirable in compressors which are used for other purposes and, therefore, the present invention is not limited to the refrigeration field, but is applicable for use with any compressible form of fluid.

In the present invention a structure is provided which is operable to compress a fluid in two independent stages. In the first stage, the fluid is drawn into the device and conveyed to an area surrounding the outer surface of an eccentrically mounted rotor where it receives its first stage of compression. The fluid is then internally transferred within the device and is compressed within the interior of the structure. An important feature of the presentdevice which makes this two stage operation possible is a stationary corelike structure which extends through the center of the rotor and which is provided with a plurality of passages that are cooperable with aligned passages in the rotor and which are operative to direct the .flow of fluid in such a manner as to provide for two stage compression. Furthermore, in order to minimize the wear of parts of the compressor, a cylinder is positioned about the rotor so as to form a sealing surface, and

means are provided for simultaneously rotating.

both the rotor and the cylinder.

An object of my invention is to provide a two stage compressor composed of a movable member and a stationary member, wherein the stationary member is provided with a plurality of passages forming fluid communication to, through, and :from the compressor.

Another object is to provide a fluid compressor having means for developing a first stage of compression on the exterior of a rotor and a second stage of compression on the interior of the rotor.

together with means within the interior of the rotor for transferring the fluid from the first to the second stage of compression.

Another object is to provide a fluid compressor having a rotor formed with two sets of radial passages therein, with a plurality of pistons arranged in one set of passages, together with a. central core member provided with a plurality of passages, cooperable with the rotor passages in such a manner as to direct fluid initially to the outside of said rotor and when compressed, the fluid is returned through certain of the same passages in the rotor and conveyed through the core to a second stage of compression on the opposite side of the pistons.

A further object is to provide a. compressor having a stationary member which is adapted to be situated along the central axis of .a rotor and which is provided with a first passage for conducting fluid into the compressor, a second passage for conducting fluid out of the compressor, and a transverse passage joining substantially opposite sides of the compressor whereby fluid may be transferred to alternate portions of the compressor.

Other and further objects may become apparent from the following description and claims and in the appended drawings in which like reference numerals denote similar parts throughout the several views.

In the drawings illustrating an application of my invention in one of its forms:

Fig. 1 is the side elevation view of the rotary compressor.

Fig. 2 is an end elevation view of the compressor.

Fig. 3 is a sectional elevation view taken on line 33 of Fig. 2.

Fig. 4 is a sectional transverse elevation view taken on line 4-4 of Fig. 3.

Fig. 5 is a sectional transverse elevation view taken on line 55 of Fig. 3.

Fig. 6 is a sectional view taken on line 6-8 of Fig. 5.

Fig. '7 is a transverse sectional view taken on line 1-4 of Fig. 3.

A- bottom support formed with an arcuate central portion l0 and feet H and I 2 connected therewith, andconnected-along the sides by bars l3, forms the base of the compressor. A cylinder l4 Fig. 4, has formed integrally therewith a 3 mutiplicity of longitudinal ribs i8 providing intervening spaces It between all pairs of said ribs. The outer edges ll of said ribs rest upon the arcuate support It and a shroud ll engages the outer edges ll of the ribs i and has flanged lips I 9 and fastened by screw bolts 2| to the base of the machine outside the limits of the arcuate an annular lip 83 engaging anannular face 84 on the flange 40. A powerful spring 98 extends between-plates ii and 32 and has the double function of holding the bellows shaft seal in sealing relation to contacted parts and at the same time yieldingly holds the entire rotor assemblage from outward movement.

Upon the shaft 4! is fixedly mounted the hub 56 of a blower fan 51 having its vanes 88 opera-' tive within an extension 59 of the shroud it which surrounds the ribbed supporting cylinder i4.

The shroud portion 59 is continued at to beyond the lower part of ribs IS on cylinder l4 as indicated in Figs. 2 and 3. Thus, although the cen ter of drive shaft 4| and of the circumferential fan blower 51 is eccentric with respect to the center of cylinde l4, the slight diiferencewhich and an inward solid shaft member or bearing post 24, which has its axis eccentrically positioned with reference to th axis of the cylinder H. The

other end of cylinder I4 is formed'with an inwardly-turned flange which supports an outwardly extended cylinder boss 26 formed with an inwardly extending annular flange 21, Fig. 3.

The above parts form the framework and support of the rotary compressor. The shaft or bearing post 24 is a highly importantfeature of my invention.

A cylindrical inner sheathing 28, Figs. 3, 4, and 5 is shrunk upon or otherwise rigidly connected with the inner wall of the cylinder I4. The sheathing 28 is of hardened steel and is turned and ground with a true polished cylindrical exposed surface. A cylindrical rotatable member 29 is provided with

flanges

39 and 3|, Fig. 3, whose outer faces form contact surfaces with oiling grooves 30', and in the channel formed by these flanges are mounted a multiplicity of rollers 32 by which the cylinder 29 is rotatably supported within the frame cylinder l4. Both the outer and inner walls of the cylinder 29 are turned and polished to smooth this brings about in the outer circumference of the limits of fan blades '58 will not prevent the fan from efliciently creating a draft through the numerous spaces I8 between ribs l4, whereby heat is effectively removed from the compressor as a whole.

It will be noted from this arrangement that the rotor comprising the body 34 thereof, the

end plates

38 and 39 and the vane-like pistons later to be described, revolves about the axis of shaft 4| and that the contact of the inner walls. of

end plates

38 and 39 upon side walls of the cylinder 29 and

cylinder extensions

30 and 3| will cause said cylinder to rotate with the rotor, and because of the eccentric relation of the axis of the rotor to the axis of the cylinder there will be progressive lateral translation of the walls of the cylinder from the maximum olfset position of the upper part of Fig. 3 to coinciding position, as shown in the lower part of Fig. 3.

As best shown in Figs. 5 and 7, a series of rectangular longitudinal slots designated SI, S2,'S3, S4,"S5, S6, S1 and S8, are provided. The front I wall of each of these slots 'lies in a radial plane true cylindrical surfaces so that the cylinder 29 l is supported for easy rotation upon the roller bearings 32.

Eccentrically positioned within cylinder 29 and supported for rotation about bearing post or shaft 24 is a piston-carrying pump rotor designated generally by the muneral 33, Figs. 3 and 5.

- This rotor comprises a central cylindrical coreor body 34 which is formed with an inner c'ylindrical surface 35 held in gas-tight contact with the outer cylindrical surface 36 of the bear-.-' ing post 24, Fig. 5. To the ends of the rotor body 34 are secured, by means of bolts 31, Fig. 3,

end plates

38 and 39. The end plate 38 has secured thereto by means of the bolts 31, a flanged extension 40 fast on a drive shaft 4| extending outwardly through an opening 42 in a closure meme I ber-43 secured by bolts 44 upon theend of cylindrical boss 23. The whole rotora'ssembl'age including the shaft 4] and parts connected therewith is supported upon a system of ball bearings 45 about the bearing post 24 and a'second system of ball bearings 43 surrounding a diminished cylindrical portion 41 at the end of bearing post 24.

Within a chamber 48 formed by the cylindrical boss 26 and the plate 43 is positioned a shaft seal which comprises a bellows member 50 united with a plate 5i which engages in metal-to-metal ,sealing relation the inner wall of closure member or plate 43. The bellows member 50 is connected at its other end with a second plate 52, which has passing through the axis of the rotor. The slots are of considerable dimensional extent transversely so that each provides a chamber having maximum volume of a considerable amount and a minimum volume of zero, according to the re-- spective positions of the parts as indicated in Figs. 5 and 7. I

It will be noted that because of the eccentric relation between the axis of the rotor 33 and the cylinder 29, a crescent-shaped chamber 63, Figs. 5 and 7, is formed. It is immaterial at which portion of the circumference of the cylinder 29 the widest portion of the crescent-shaped chamber 63 shall be, but in practice the axes of the rotor 33 and the cylinder 29 are horizontal and lie in a vertical plane which brings the widest portion of the crescent-shaped chamber 63 at the top of the rotor 33 and the contact of the outer walls of the rotor with the inner walls of the cylinder 29 in the same'vertical plane at the bottom thereof. I

As indicated above there are eight longitudinal chambers, Si through S8, extending outwardly through the outer marginof the body "34 of the rotor 33. Within these longitudinal chambers are mounted for substantially radial outward and inward movements along them a series of pistonlike members which for convenience are designated as Pl, P2, P3, P4, P5, P6, P1 and P8. These members are referred to herein as pistons. They are all identical in form having parallel side walls adapted when covered with an oil film to make agas-tight seal with the walls of the longitudinal chambers SI through S8, and hav ing a right-angled bottom wall outer curved'wall 34.

The curve of this outer wall is taken on a radius the same as that of the radius of the rotor. Hence, at the end of the compression stroke the full curve 'of the outer wall will engage the curved inner surface of cylinder 23, and as the rotor revolves and the pistons are thrust outwardly against said inner wall the curved outer wall of the pistons will in part lose contact at the rear side thereof, but the forward end of these pistons will continue to make sealing contact.

a'nd an .During rotation of the rotor 33, both the action of centrifugal force, and also the compressed gas back of the pistons, holds the pistons PI through P3 with their forward edges, continuously in contactwith the inner cylinder wall of cylinder 23. The crescent-shaped chamber 63 is thus divided into a series of pockets or supplemental chambers CI, C2, C3, C4, C5, C3, C1

and C8. Having reference to the direction of rotation of the rotor and the pistons slidabiy continuously expanding chambers and the last four of the chambers C5, C5, C1 and C8 are continuously contracting chambers. It follows that if air or other gas is delivered to the expanding chambers CI, C2, C3 and C4, such gas will co'n tinually move into the chambers under whatever degree of pressure the delivery is made, until the fully expanded chamber C4 is filled. Thereafter if the same gas remains in the contracting chainbers, C5, C6, C1 and C8, it must be continually compressed to such point as release from the con-. tracting chamber, as C8, may have taken place. The bearing post 24, which supports the rotor 33, as distinguished from the enveloping cylinder 29, is provided with systems of chambers and passageways by means of which inlet air or other gas is introduced into the expanding chambers CI, C2, C3 and C4 and compressed gas is withdrawn from the contracting chambers, C5,;Cl, C1 and C8 and passed from there into the expanding piston chambers SI, S2, S3 and S4, with additional passages from which the doubly coinpressed gases are carried from the compressor to the storage member.

Having reference to Figs. 3, 5, and 6, the travel of inlet gas is as follows:

. leads to annular admission chamber 51 within the cylinder I4 and in front of. the inwardly ports or passageways bearing post 24, and the chamber I I has its outer arc length such that .three sets of ports 12 may simultaneously open from chamber II to expanding chambers C2, C3 and C4, as shown in Fig. 5. It follows that as each expanding chamber C2, C3 and C4 is caused by rotation of rotor 34. successively to pass the arcuate limits of chamber II,- the inlet gas will be caused to move through the sets of ports I2 into the expanding chambers connected therewith, thus fully filling chamber C4 when-- it reaches its maximum expansion.

As the'rotor body 34 is carried about the bearing post 24 the sets of ports I2 will successively be blocked or closed by the solid marginal part of bearing post 24, Fig. 5, until they come opposite an arcuate chamber I3 of substantially the gas travels, since in these positions the ports 12 will be in communication with arcuate chamber 13. i

From said arcuate chamber runs a diagonally extended transverse passageway I4, Fig. 6. The angularly-disposed passageway I4 terminates in an arcuate chamber I5 on the opposite side of the bearing post 24 from the chamber I3. Chamber I5 is on the same side of said bearing post as is chamber 7 I, but positioned toward the other or left hand end, as clearly indicated in Fig. 6

and indicated in dotted lines in Fig. 3.

The chamber I5 is thus positioned adjacent the left hand portions (as in Fig. 3) of the expanding piston chambers SI, S2, S3 and S4. The

. chamber I5 will be successively connected with the expanding piston chambers SI, S2, S3 and turned flange 25, Fig. 3. This'boss is adapted to be secured to any source of gas supply (not shown) such as a gas to be compressed for effecting cooling by evaporation. The inlet gas-is, therefore, always presentoutside of the rotor head 38 and surrounding the shaft-flange extension 40 which connects with and rotates the rotor 33 supported by bearing post 24. Within the bearing post 24 is formed a longitudinal bore or chamber 68 which extends centrally through diminished cylindrical portion" thereof and enters a chamber 69 formed in the head of shaft H and extension 40. From the chamber 63 are extended a series of openings I0 which lead into the chamber 61, thus connecting the chamber 58 in bearing post 24 with the inlet supply of gas.

The chamber 68 is connected with a radially- L shown three in each set) ofradially-extended S4 by means of ports I6 leading through the rotor body 34 into the bottoms of the expanding chambers, there being a set of said ports, as shown two, Fig. 6, for each of said piston chambers.

Diametrically opposite the chamber I5 in the bearing post 24 is an arcuate chamber 11 which connects with a passageway I8 that conveys the compressed'gas outside the compressor to a desired point of storage.

Fromthe' above it will be apparent, considering Figs. 6 and 7, that the gas is first compressed in the contracting chambers C5, C5, C1 and C3,

and that this compressed gas is transferred through passageway I4, chamber 15, and ports "successively to the expanding piston chambers SI, S2, S3 and S4, so that these chambers contain gas having one step of compression already effected. Continued rotation of the rotor blocks the ports I6 and causes the expanding chambers SI', S2, S3 and S4 successively to become the contracting chambers S5, S6, S1 and S8. The pistons'P5, P8, P1 and-P8 themselves then become compressors, bringing about a second stage 7 of compression before delivery of the compressed gas through a suitable connection (not shown) with passageway I8.

The converse of this progressive multiple compression is likewise progressive multiple evacuation or exhaustion of gas from any container thereof connected with the compressor pump.

The shaft 4| will, of course, be connected with any suitable source of power, but the compressor is designed to operate at fairly high speed, say 1800 R. P. M. As shown particularly in Fig. 4, having reference to Fig. 3, the chamber 61 is adapted to hold a body of oil I9 up to a level indicated at 80. Openings 8| are extended into

sight tubes

82 and 83, closed by

sight glass

84 and 85, which enables the operator from time to time to observe the condition of the oil at the bottom of chamber 61. This oil may gravitate under rollers 32 which are thus kept oiled and will by splash oiling continuously effect oiling of roller bearings 45 and 46 and pistons Pl P8. Chamber 6'! which is connected past the roller bearings with a chamber 86 is completely sealed from gas leakage by the metal-to-metal seal of disk head 22, with supporting cylinder (4 and the effective bellows shaft seal 50 at the other side thereof.

The advantages of my invention, which have been indicated to a considerable degree in connection with the description given in the foregoing specification, are pronounced and important. A primary clear-cut advantage is in the provision of means for two-step compression. This, taken with thehigh relative speed of the rotary compressor enables a compressor of remarkably small size and compact form to deliver compressed gas in surprisingly large volume and at a very high degree of compression. Thus the drawings, except for Figs. 2 and 6, illustrate, full scale, a compressor which will handle a larger volume of gas and compress it to a higher degree than a two cylinder piston compressor of common construction many times the size and weight and requiring consumption of much more power.

'A further great advantage resides in the substantial elimination of friction. The cylinder shell 29 rotates with the rotor 33 so there is substantially no friction between the inner wall of this cylinder and the outer ends of the pistons Pl-PB. The cylinder 29 rotates freely on oiled roller bearings whilethe rotor 33 rotates upon ball bearings. The distribution of oil from the ol pool at the bottom of the frame cylinder l4 and extending into chambers 61 and 86 insures constant oiling of the rollers 32 and also, through the passages connecting with chamber 69, oiling of the pistons Pl-P8, the roller bearings 45 and 46 and the outer walls of bearing post 24.

A further very great advantage of my invention comes from the control of air passages for inlet gas, first and second stage compression,

the place of storage. This provides at one and the same time short accurate passages through which the gas can move and equally accurate automatic valve means eifected by movement of the rotor itself.

Another great and novel advantage in my invention resides in the fact that the ends of the rotor itself and of the piston compression chambers SI to S8, inclusive and particularly the high compression chambers S4, S5, S6 and S! are sealed absolutely gas tight by the

end plates

38 and 39 bolted through bolts 31 directly upon the faces of the rotor as these contacting faces have been milled and are supported to be absolutely parallel. The resulting metal to metal seal is of a nature which can not be penetrated by gas of any nature or at any degree of compression.

A further great advantage of my invention comes from the compact and yet extremely strong and sturdy frame support for the rotating members. This support, including a very large number of heat radiating ribs and intervening heat exchange passages together with blower means operated directly from the shaft of the rotor for carrying currents of air through these heat exchange passages, is unusually efiective for heat withdrawal.

Many other advantages flow out of my invention, among which is the extraordinary efficiency of the device as an evacuator for producing any desired degree of vacuum.

I claim:

, 1. A rotary compressor, comprising a cylinder, a rotor of smaller cross-dimension than the cylinder mounted within said cylinder and having its axis eccentric to the axis of the cylinder, said rotor having a plurality of radial slots therein, a plurality of radially movable pistons carried in the slots in said rotor in such a manner as to form a first plurality of compression chambers between said cylinder and said rotor and a second plurality of compression chambers within the interior of said rotor, means for introducing fluid into said first plurality of compression chambers, means for conducting fluid from said first plurality of chambers to the interior of said rotor, and a stationary member positioned in the axial center of said rotor, said member having a passage extending transverse to the axis of said member and said rotor and forming a fluid cone nection between the interior of said rotor and said second plurality of compression chambers.

2. A two stage rotary compressor, comprising a cylinder, a rotor of smaller cross-dimension than the cylinder positioned in said cylinder and having its axis of rotation eccentric to theaxis of the cylinder thereby forming a crescentsh'aped area between the rotor and the cylinder, said rotor having a first plurality of radially extending apertures operable to provide passage of a fluid from the interior of said rotor to a first portion of said crescent-shaped area and return of fluid from a second portion of said area to the interior of said rotor whereby the fluid is compressed in one stage, said rotor having a second plurality of radial extending apertures which are operable to receive compressed fluid from the second portion of said crescent-shaped area, a plurality of radially movable pistons in said second plurality of apertures and being operable on movement of the rotor to compress fluid in said crescent-shaped area and also to compress fluid in said second plurality of apertures whereby the fluid is compressed in a secnd stage, and a stationary member positioned on the interior of said rotor and having 9. 1 sage communicating with said first and said second plurality of apertures in said rotor.

3. A two stage rotary compressor, comprising a cylinder, a rotor of smaller cross dimension than said cylinder positioned in said cylinder and having its axis of rotation eccentric to the axis of the cylinder thereby forming a crescentshaped area between the outer surface of the rotor and the inner surface of the cylinder, said rotor having a first plurality of passages forming open communication between the interior of said rotor and said crescent-shaped area, said rotor having a second plurality of radial passages, a plurality of radially movable pistons positioned in said second plurality of passages in such a manner as to block the outer ends exterior thereof, said rotor having a second pluof said passages, and a stationary member positioned on the interiorof said rotor. said stationary member having a first passage communicating with one of said first plurality of pas sages in said rotor to admit fluid to a first part of said crescent-shaped area, a second passage cooperable with another of said first plurality of passages in said rotor to permit passage of fluid from a second portion of said crescentshaped area to one of said second plurality of passages in said rotor when its respective piston is in an outwardly moved position, a third passage communicating with one of said second plurality of rotor passages when its respective piston is in an inwardly moved position. said third passage providing egress for compressed fluid.

4. A two stage rotary compressor, comprising a 'casing, a cylinder supported for rotation within said casing, a tubular rotor of smaller cross dimension than said cylinder supported for rotation within said cylinder and having its axis eccentric to the axis of said cylinder whereby a compression chamber is formed between the outer surface of said rotor and the inner surface of said cylinder, said rotor having a first plurality of radially disposed passages forming a fluid communication between the interior and of radially movable pistons positioned in said second plurality of passages, the linear dimensions of said pistons being less than the linear dimensions of their respective passages whereby a chamber is formed in each passage on one side of each of said pistons, means for simultaneously rotating said cylinder and said rotor in such a manner that the pistons are moved outwardly by centrifugal force and moved inwardly by the eccentric relationship between said rotor and said cylinder, and a stationary cylindrical member extending axially through,

the center of said rotor and having a plurality of passages therein, one of said passages extending through said member in a plane which is transverse to the axis of said member and said rotor, said passage forming an internal com munication between one of the passages of said first named plurality of rotor passages and one REFERENCES CITED The following references are of record in the file of this patent:

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