US2846138A - Refrigeration compressor - Google Patents

Description

5, 1958 c. E. RACKLYEFT 2,846,138

REFRIGERATION COMPRESSOR 2 Sheets-Sheet 1 Filed Dec. 16, 1954 INVENTOR. Car! 5. Rack/yefz. BY Mud WM 2 Sheets-Sheet A TTOR/VE Y5 Aug; '5, 1958 v c. E. RACKLYEFT REFRIGERATION COMPRESSOR Filed Dec. 16, 1954 United rates REFRIGERAHQN COMPRESSOR Carl E. Racldyeft, Arkansas City, Kane, assignor to Acton Manufacturing Company, Inc., Arkansas Qity, Kane, a corporation of Kansas This invention relates to a fluid pressure system and rotary compressor therefor, particularly to a rotary gas compressor and the lubricant circulation therefor in fluid pressure systems such as refrigerating systems and the like.

The objects of the present invention are to provide a rotary gas compressor with blades in the rotor, offset from radial planes extending through the axis of said rotor and with rounded outer ends on said blades engaging the inner surface of the cylinder wall of the compressor; to provide such a compressor with a passage communicating with the blade slots in the rotor behind the blades and connected with a liquid pressure supply whereby said pressure will force the blades out against the cylinder walls; to provide a rotary gas compressor and gas liquid separator in a refrigerating or other fluid pressure system whereby liquid lubricant and the like delivcred with compressed gas to the separator is separated, dry gas going to the remainder of the refrigeration apparatus and the liquid lubricant being returned under substantially the discharge pressure of the compressor through passages communicating with the blade slots in the rotor to force the blades out against the cylinder wall and seal and lubricate the blades and cylinder walls; to provide such a compressor with clearance between the rotor and cylinder wall and an enlarged chamber in the compressor discharge passage which cooperate to permit the compressor to maintain suitable discharge pressures and maintain suitable differential pressures in refrigeration systems at a wide variety of speeds of operation; and to provide a rotary gas compressor and separator arrangement for use in refrigeration systems such as automobile air conditioning units which will provide suitable refrigeration differential pressures at all speeds of operation and substantially eliminate excessive head pressures and freeze ups in the apparatus.

in accomplishing these and other objects of the present invention, I have provided improved details of structure, the preferred forms of which are illustrated in the accompanying drawings wherein:

Fig. l is a diagrammatic view of a refrigeration apparatus including a rotary compressor and separator.

Fig. 2 is a perspective view of the rotary compressor.

Fig. 3 is a transverse sectional view through the rotary compressor taken on the line 33, Fig. 4.

Fig. 4 is a longitudinal sectional view through the rotary compressor taken on the line 4-4, Fig. 3.

Fig. 5 is a transverse sectional view through the rotar compressor on the line 55, Fig. 4.

Pig. 6 is a vertical sectional view through the separator.

Fig. 7 is a transverse sectional view through a strand of the filamentous material in the separator.

Referring more in detail to the drawings:

1 designates a refrigeration system including a rotary gas compressor 2 having an intake connected by a low pressure gas line 3 to the outlet of an evaporator 4. The discharge of the compressor is connected by a high pressure gas line 5 to a separator 6, preferably intermediate 2,846,138 Patented Aug. 5, 1958 "ice pressure is forced from the separator 6 through a gas line 12 to a condenser 13 and the liquid from the condenser moves through a line 14 to a liquid receiver 15. The liquid from the liquid receiver moves through a line 16 under control of a valve 17 to the evaporator 4.

The valve 17 has a thermal connection 18 with the line 3 adjacent the evaporator 4 whereby said valve 17 is responsive to the temperature of the low pressure gas leaving the evaporator.

The condenser 13, liquid receiver 15, valve 17 and the evaporator 4 are of conventional structure and operation and the specific construction thereof forms no part of the present invention.

The compressor 2 includes a shell 19 having an openended cavity or bore 20. A sleeve or liner 21 is pressed or otherwise secured in the bore 20 whereby said sleeve defines the cylindrical wall of a cavity 22 for a rotor 23 and associated parts. I

The rotor cavity is closed by an end plate or cover member 24 secured to the open end 25 of the casing 19 by suitablefastening devices such as screws 26. The cover plate is provided with a bearing recess 27 in which is mounted an antifriction bearing 28 rotatably supporting one end 28 of a rotor shaft 29. The cover plate is also provided with a counter bore 30 substantially corresponding in diameter to the bore 20. A plate 31 is mounted in the counter bore 30 in engagement with the antifriction bearing 28 and having an inner face 32 engaging the adjacent end of the sleeve 21. The other end of the cavity 20 in the casing 19 terminates in a wall 33 on the opposite side of which is mounted a casing extension 34. The wall 33 has an opening 35 through which the shaft 29 extends, said opening communicating with a bore 36 in the extension 34.

The extension 34 is provided with and a cover plate 39 closes the counter bore and is secured to the extension by suitable fastening devices such as screws 40. The cover plate 39 has a portion 41 which fits in the counter bore 37 and the inner end of said portion is provided with a bearing recess 42 in which is located an antifriction bearing 43 for supporting the shaft in the extension. The plate 39 has a bore 44 through which the adjacent end of the shaft 29 extends, said portion of the shaft being adapted to have a pulley 45 mounted thereon or otherwise be connected to a suitable source of power for driving the compressor. The cover plate 39 has a recess adjacent the bearing 43 for receiving a seal member 46 adapted to engage the shaft to form a lubricant seal. Arranged in the bore 36, between the wall 33 and the bearing 43, is a rotary seal 47 having one end fixed to the shaft and the other end bearingon the cover plate portion 41 and bearing 43 to provide a gas tight seal whose efficiency is increased by pressure there- The rotor 23 consists of a cylindrical member 48 secured to the shaft 29 as by keys 49 and said cylindrical member 48 is provided with a plurality of inwardly extending slots 59 spaced around the circumference thereof. The slots 50 extend the full length of the cylindrical member 48 and are at an angle to radial planes which extend through the axis of said member 48 whereby the bottoms of the slots extend alongside and are spaced from the shaft 29. Blades 51 are slidably mounted in the slots 5%) and are provided with rounded outer edges 52 adapted to engage the inner surface of the sleeve 21, said blade;

a counter bore 37 extending inwardly from the open end 38 of the extension being of such length that the ends thereof engage the plate 31 and inner surface of the wal 33. Also the blades are of less depth than the slots whereby said blades may be moved inwardly in said slots until the round edges of the blades are within the periphery of the cylindrical member 43.

The bearings 23 and 43 are so arranged that the rotor is eccentrically mounted in the cavity 22 whereby the periphery of the cylindrical member 48 at the line thereon closest to the interface of the sleeve 21 has a spacing approximately .615 of an inch. The sleeve 23 is provided with an inlet port 54 preferably positioned substantially 90 from an axial plane extending through the line on the cylindrical member that is closest to the sleeve. The inlet port 54 communicates with a chamber 55 in the casing 19 which is suitably connected to and in communication with the low pressure gas line 3.

A circular outlet port 56 is arranged in the sleeve 21 on the opposite side from the inlet port 54, said outlet port preferably being positioned whereby the edge thereof closest to theline where the rotor is closest to the sleeve and is spaced therefrom approximately one-half the spacing between'the slots 59. The outlet port 56 communicates with a cavity 57 in the casing 19, such cavity forms a high pressure chamber, the chamber being in communication with and suitably connected to the high pressure gas line 5 which leads to the separator 6.

The cold oil line 9 is connected as at 58 with the cover plate 2 whereby said line is in communication with an axial bore 59 in the shaft '29, said bore extending from the end 28 of the shaft and terminating as at as in spaced relation to the plate 33. The bore 59 is in communication with radial branches 61 extending outwardly through the shaft and into the cylindrical member 38 of the rotor to provide communication between the bore 59 and the bottoms of the slots St).

The separator 6 has a top wall 62 and depending side walls 63 terminating in inwardly and downwardly sloping walls 64 connected by a bottom wall 65. A perforated plate 66 is arranged at the upper end of the sloping walls 64- to cooperate with the top wall 62 and side walls 63 in defining a chamber 67 in the upper portion of the separator. The plate 66 also cooperates with the walls 64- and 65 to define a liquid collecting chamber 68.

The chamber 67 is preferably substantially filled with non-hygroscopic filamentous material. it is preferred that the filamentous material 69 be composed of thin filaments or strands 7'1) that have irregular or rough surfaces. I have found that a very satisfactory filamentous material is a wool-like mass consisting of a plurality of metal filaments of copper or other suitable material cut substantially triangular in cross-section with two surfaces rough and irregular as at 71 and the outer surface substantially smooth as at 72. This material is preferably relatively hard and is cut from bar stock in long filaments and is packed in the chamber 67 at a density of 3 /2 to 5 pounds per cubic foot.

The gas, such as Freon, compressed by the compressor 2 and delivered through the high pressure gas line 5 to the separator 6 enters the separator at pressures of from 90 to 180 pounds per square inch and carries a small amount of oil or other liquid used for lubrication and sealing the compressor. As the gas passes over the many rough surfaces on the filaments, the rough surfaces scrub the liquid from the gas causing the liquid to collect in the pockets formed by the roughness of the filaments and as it accumulates in droplets to move to the perforated plate 66 and through the openings therein and into the chamber 68. This removal of the liquid from the gas substantially dries the gas and the dry gas moves under pressure through the line 12 to the condenser 13. The liquid collects in the chamber 68 and a sufficient quantity of liquid is maintained in the system to maintain a level thereof in the chamber 63 above the outlet connection 73 that extends through the bottom wall 65 and corn- 4 municates the chamber 68 with the oil line leading to the oil cooler S. The pressure throughout the separator is substantially equal therefore the pressure acting on the liquid level tends to force liquid through the line '1, cooler 8 and line 9 to the compressor and into the bore 59 in the shaft 29 and behind the blades Sll where the pressure tends to force the blades outwardlyagainst the inner surface of the sleeve 21.

In operatin a fluid compressor system constructed and assembled as described, a suitable quantity of liquid,

such as oil, is placed in the oil cooler 2% and bottom of the separator 6 to raise the level in the separator chamber 68 substantially above the outlet connection 73. Then the prime mover 11 is operated to rotate the shaft 25 and rotor thereon in a counterclockwise direction, Fig. 3. Rotation of the rotor tends to move the blades 51 outwardly whereby the rounded ends 52 thereof engage the inner surface of the sleeve 21. The rotation of the rotor and blades thereon tend to draw gas through the inlet port 54 and then move the gas toward the outlet port 56 and due to the relative positioning of the rotor and sleeve, the chamber therebetwecn and between adjacent blades progressively decreases toward the outlet port, compressing the gas and forcing same through the outlet port into the high presure chamber 57 and through the line 5 to the upper portion or chamber 69 in the separator 6, the gas moving on through the line 12 to the condenser 13, line 14 to the liquid receiver 15 and then through the line 16 under control of the valve 17 to the evaporator 4, the gas then moving through the low pressure return line 3 to the inlet port 54 of the compressor. Any liquid in the gas delivered to the separator 6 is separated therefrom and collected in the chamber 68 where the pressure acting on said liquid forces same through the line 7, oil cooler 8 and line 9 to the bore 59 in the shaft 29 and then through the passages 61 to the slots 50 behind the blades 51 to apply pressure thereto to force same into tight engagement with the inner surface of the sleeve 21. The liquid pressure behind the blades continuously acting on said blades tend to eliminate any rebound of the blades from the cylinder wall thereby reducing noise and increasing efiiciency of the compressor. Some of the liquid or oil is forced outwardly through the slots 50 past the blades 51 to the inner surfaces of the cavity 22 to provide lubricant and a seal between the blades and the Walls of the cavity.

The chamber 57 tends to reduce the pulsations and variation in the discharge pressure of the compressor and therey reduces the heat formed by the compression of the gas. Also when operation of the valve 17 tends to cause the discharge pressure of the compressor to be increased beyond the desired amount, the clearance between the rotor and the sleeve adjacent the outlet port allows some of the pressure to be bled thereby further aiding in maintenance of a lower operating temperature in the compressor.

I have found that with this arrangement of the high pressure chamber 57 and the clearance between the rotor and sleeve, the efliciency of the compressor at normal operating discharge pressures up to approximately 200 pounds per square inch is very good, the compressor being capable of operating at low suction pressure and also when under load even with discharge pressures of 200 pounds per square inch, there is no tendency for the compressor to overheat. The small quantity of oil entrained in the gas discharged from the compressor when discharged with the gas into the chamber 69 conta ning the filamentous material, impinges on the rough surfaces of said material and gathers in droplets on these surfaces and runs down into the collecting chamber 68 at the bottom of the separator. The density of the filamentous material is relatively low and therefore there is little hindrance in the passage of the gas through the filamentous material and on to the condenser. With the particular separator constructed as described, only a trace of oil has ever been found in the liquid gas moving from the condenser.

It is believed obvious that I have provided a fluid pressure system and rotary gas compressor therefor wherein liquid, under pressure, is supplied at all times to the inner ends of the rotor bladestto hold said blades in operating engagement with the walls of the compression chamber and to provide lubricant and a liquid seal between operating parts and a structure that can operate efiiciently and substantially trouble-free at a very wide range of speeds and provide suitable discharge pressures and differential pressures in the system.

What I claim and desire to secure by Letters Patent is:

A compressor for use in a refrigeration system using a suitable refrigerant gas and for maintaining suitable differential pressures therein when operated at a wide variety of speeds comprising, a casing having a cylindrical bore closed at both ends to form a cylindrical cavity therein, inlet and outlet passages in said casing, inlet and outlet ports communicating the inlet and outlet passages respectively with said bore, said ports being circumferentially spaced with the distance therebetween at one side of the bore substantially greater than at the other side, said casing having chambers therein adjacent to and in communication with the respective ports, a shaft having an axial bore rotatably mounted in the casing bore in eccentric relation therewith, a cylindrical rotor fixed to the shaft in the casing bore whereby said otheraside of the casing bore and said rotor and said one side of the casing bore cooperate to define a compression chamber of progressively decreasing volume from the inlet port to the outlet port, the periphery of the rotor being closest to the cylindrical bore at said other side thereof and adjacent the outlet port with the spacing from said other side of the cylindrical bore being approximately .015 inch,

said rotor being provided with a plurality of longitudinal slots spaced circumferentially around the rotor, said slots being inclined relative to radial axial planes through the rotor with the inner ends of said slots laterally spaced from the shaft, blades slidably mounted in the slots and having rounded outer ends adapted to engage the casing bore, and means communicating through the axial bore of the shaft for inducing lubricating oil into the slots behind the blades whereby said oil lubricates the cylindrical bore and acts as a seal between said blades and said cylindrical bore, the operation of the compressor being such that with the approximate .015-inch spacing between the rotor and said other side of the cylindrical bore the gas discharge pressures are maintained between and 200 pounds per square inch between minimum and maximum operating speeds.

References Cited in the file of this patent UNITED STATES PATENTS 1,280,765 Kramer Oct. 8, 1918 1,352,750 Jackson Sept. 14, 1920 1,635,006 Oliver July 5, 1927 1,867,719 Van Deventer July 19, 1932 1,928,300 Peltier Sept. 26, 1933 1,934,189 Grier Nov. 7, 1933 2,057,381 Kenney et al. Oct. 13, 1936 2,149,358 Miller Mar. 7, 1939 2,305,317 Nickell Dec. 15, 1942 2,455,297 Curtis et al Nov. 30, 1948 2,606,715 Martin Aug. 12, 1952 2,633,292 Voznica Mar. 31, 1953 2,639,855 Daniels May 26, 1953 2,678,156 Henderson May 11, 1954

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