US2846140A - Refrigeration compressor - Google Patents

Description

1958 J. M. KEMPER 2,846,140

REFRIGERATION COMPRESSOR Original Filed June 9, 1947 2 Sheets-Sheet 1 Zmventor JAMES M. KEMPER (Ittorneg Aug. 5, 1958 J. M. KE MPER ,1

REFRIGERATION COMPRESSOR Original Filed'June 9, 1947 2 SheetsSheet 2 Zhwentor JAMES .M; KEMPER l (Ittbrneg States REFRIGERATION CDMPRESSOR Continuation of application Serial No.

753,441, June 9, This application September 17, 1952, Serial No.

4 Claims. 01. 230-232 The present invention relates generally to refrigerating apparatus, and is more particularly concerned with motorcompressor units for use in refrigerating apparatus of the compression type, wherein the motor and compressor are enclosed within a hermetically sealed casing.

The present application constitutes a continuation of my copending application Serial No. 753,441, filed June 9, 1947, now abandoned.

In units of the motor-compressor type as described herein, valve noises have in many cases proved objectionable and very difiicult to eliminate. Attempts have been made to utilize a muffier for suppressing or eliminating such noises, but these mufiiers have in the main been so constructed that they could become filled with oil, whereupon an additional slug of oil from the compressor might subject the mufiier to a sufficiently high pressure to cause bursting. As a further object, the present invention provides an improved muffier arrangement which is so constructed that it will normally form a receiving chamber wherein a slight back pressure will be built up, and upon the occurrence of this pressure, relief means will be actuated to permit the discharge of fluid and draining of any accumulated oil.

Further objects of the invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations on the scope of the invention as defined in the appended claims.

Referring to the drawings, which are for illustrative purposes only:

Fig. l is a side elevational view of a motor compressor unit embodying the features of the herein described invention;

Fig. 2 is an end elevational view looking toward the pumping end of the unit, a portion of the casing being cut away to disclose certain details of internal construction of the casing;

Fig. 3 is an enlarged vertical sectional view of the unit, taken substantially on line 33 of Fig. 2;

'Fig. 4 is a fragmentary end view of the motor stator and rotor parts showing certain constructional details thereof;

Fig. 5 is an exploded view showing the construction and inter-relation of the valve parts;

Fig. 6 is a sectional view through the suction head, taken on the line 66 of the uppermost part of Fig. 5; and

Fig. 7 is an isometric view of the mufiler, a portion being cut away to show details of construction.

Referring now to the drawings, it will be seen from Figs. 1, 2 and 3 that the motor-compressor unit of the present invention is of very compact construction of neat appearance, and comprises a sealed casing of two part construction, namely, a compressor part A and motor part B. The casing is generally l..-shaped in appearance with the compressor part forming the vertical leg and the motor part of the horizontal leg.

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Patented Aug. 5, 1958 The casing part A has a cylindrical opening 10 on one side which is peripherally surrounded by a groove 11 and a connection flange surface 12. The casing part B is of hollow construction, generally cylindrical in shape and having one end closed and the opposite end open. The open end of the casing part B is provided with a connection flange 13 adapted to abut and be secured against the flange surface 12 as by a plurality of securing screws 14. The inner edge portion of the connection flange 13 is provided with a groove 15 for registration with the groove 11, these two grooves providing a space for receiving the peripheral edge portion of a bearing spider 16 which is secured within the groove 11 as by a plurality of circumferentially spaced screws 17, the heads of these screws projecting into the groove 15.

The bearing spider 16 has radially extending portions separated by openings or open areas 18 therebetween to provide communication between the opposite sides of the bearing spider. This bearing spider separates the interior of the casing into a compartment 19 for the pumping elements as will be hereinafter described, and a compartment 20 containing the motor for driving the pumping elements. The bearing spider is formed at its center with a tubular hub 21 for supporting an anti-friction bearing assembly 22 which is retained against movement in one direct-ion within the hub by a retainer ring 23 against which it abuts.

The bearing 22 forms a support intermediate the ends of a shaft 24 which is rotatably mounted in this hearing with one end portion projecting into the compartment 20 and its other end portion projecting into the compartment 19. This latter end of the shaft 24 is supported by an anti-friction bearing assembly 25 supported within the annular wall of a tubular bearing support 26 which in this case is integrally formed with the adjacent wall portion of the casing part A. The anti-friction hearing assembly 25 is composed of an inner ball race 25a which is clamped to the shaft end between a shaft shoulder 27 and a washer 28 secured over the end of the shaft by a screw 29. A compression spring 30, which is seated within the tubular bearing support, has one end bearing against a thrust washer 31, which engages against the outer bearing race 25b of the anti-friction bearing as sembly 25. With this arrangement, the shaft is rotatably supported, and the spring 3t acts to bias the shaft axially in a direction toward the bearing spider 16 and maintains a shaft shoulder 32 in continuous abutment with the inner ball race 22a and the outer ball race 22b of the antifriction assembly 22 continuously in abutting engagement with the retainer ring 23. By mounting the shaft in this manner, close clearances are eliminated and the shaft may readily respond to changes due to temperature variations.

The shaft section within the compartment 19 is provided with one or more cranks 33, depending upon and corresponding to the number of pumping pistons in the compressor. The upper portion of the casing part A is formed with one or more cylinder bores 34 Within each of which there is reciprocably mounted a piston 35, each piston being connected by a wrist pin 36 to the upper end of an associated connecting rod 37 having a connection at its lowermost end with the crank 33.

Lubrication of the bearings and rotatable parts within the compartment 19 is accomplished by means of oil scoop members 38 carried at the lowermost ends of the v connecting rod connection with the crank shaft, these oil scoops being adapted to dip into lubricating oil in the bottom of the casing, this oil being normally maintained substantially at the oil level as indicated by the numeral 39. It will be observed that the oil level is the same in both compartments 19 and 20, since free access between 3 p the compartments is established through the openings or open areas 18 of the bearing spider.

The upper ends of the cylinder bores 34 terminate in a planar upper surface which is capped by a hollow head member 41 seated on a sealing gasket 42 at its periphery on the surface 40 and secured in place by a p-lurality of head screws 43. The head member coacts with the surface 40 to form a collecting chamber and valve compartment 44 within which the valve assembly for each cylinder is mounted.

As shown in Fig. 2, adjacent and alongside the aligned cylinders, the casing part A is cored or otherwise formed to provide an interior wall cavity 45 which communicates at its lowermost end with the interior of the compartment 19 and at its uppermost end with an inlet port 46 which opens into the surface 41 a port 46 being provided for each cylinder valve assembly. With two cylinders, as illustrated in Fig. 3 of the drawings, two inlet ports 46 would be provided.

Each valve assembly consists of a reed suction valve 47, a valve plate 48, a reed discharge valve 49, and a suction head 50. These valve elements are assembled in stacked relation and secured by holding screws 51. The reed valve members 47 and 49 are relatively held in proper position by small positioning pins 52 which are inserted into aligned openings 53-,53' and 54-54 of these members.

The inter-relation of the valve elements to the cylinder bore is best shown in the exploded view, Fig. 5. Fluid flow during suction stroke of a piston will be as follows: From the inlet port 46, fluid will flow through registered openings 46a, 46b, and 460 in the valve elements 47, 48, and 49 respectively. From the opening 460, the fluid flows into a passage or cavity 53a in the suction head 50, as shown in Fig. 6. The passage 53a interconnects opening 460 with the adjacently disposed opening 54b of the valve element 49. The opening 54b is in registration with an opening 54a through the valve plate 48. The underside of the opening 54a is closed by the end portion of a flexible tongue formed in the reed suction valve member 47. The tongue 50 being disposed over the cylinder bore 34 will be drawn away from the lower end of the opening 54a, during suction stroke of the piston, thus permitting fluid to pass into the cylinder.

During compression strokes of the piston, the compressed fluid is forced through an opening 56 in the reed suction valve member 47, the opening 56 being in registration with an opening 56a in the valve plate 48. The uppermost end of the opening 56a is formed to provide a seat for the end portion of a flexible tongue 57 formed 0 in the reed discharge valve member 49. The tongue 57 underlies a rib 58 which extends across a discharge opening passage 59'through the suction head 50, the lowermost edge of the rib 58 being upwardly curved as shown in Fig. 6, and indicated by the numeral 60 to permit limited upward flexing of the tongue 57 to open position in relation to the opening 56a.

Ordinarily, compressed fluid which is discharged through the discharge opening 59 would pass directly into the valve compartment 44 and pass out into the refrigerating system through an outlet conduit connection 61. In the present invention, however, a hollow cover member is provided, as shown in Fig. 7. This member is of relatively thin Walled substantially rectangular construction, and may be stamped or otherwise formed from a flat metallic sheet so as to form a dished imperforate cover as generally indicated by the numeral 62. As shown in Fig. 3, the cover 62 is mounted in inverted .position with its brim forming edge 63 seated on the surface 40 so as to cooperate therewith and enclose the valve assemblies. One or more spring strips 64 riveted or otherwise secured to the outermost surface of the upper wall portion of the cover have curved end portions forming spring fingers 65 which are adapted to 4 bear against the underside of the head member 41 to resiliently bias the cover 62 downwardly into seated closed relation with the surface 40.

The cover 62 thus coacts with the surface 40 to form a fluid receiving chamber within the valve compartment for initially receiving the fluid as it is discharged from the valve assemblies. This cover serves as a muffler for suppressing the operating noises of the valves and will remain in closed position until a predetermined pressure, depending upon the graduation of the springs 64, builds up within the receiving chamber. The spring fingers 65 may be so graduated as to permit a back pressure of four to five pounds per square inch to build up within the receiving chamber, whereupon the cover 62 will be raised sufficiently to permit passage of fluid from the receiving chamber into the valve compartment, and thence through the outlet connection 61. It will be observed that any oil which might accumulate around the valve assembly within the receiving chamber under the cover 62 will be permitted to drain out of this chamher when the cover is raised and be carried into the refrigerating system along with the refrigerant. The danger of bursting the mufiler in such an arrangement is therefore entirely eliminated.

The motor for actuating the pumping elements is contained Within the casing part B and comprises a rotor element 66, which, in this case, is for purposes of illustration disclosed as being of the squirrel cage type, and a stator winding assembly 67.

The rotor element, which may be of conventional construction, is provided with a central tubular hub 68 having an internal abutment shoulder 69 which is engaged by the peripheral edge portion of a retaining washer 76 whichv is secured by a holding screw 71 to the end of the shaft 24. A spacer sleeve 72 surrounds the shaft end and is positioned between the inner ball race 22a of the anti-friction bearing 22 and the adjacent end of the hub 68 to limit and locate the rotor on the. shaft.

The stator winding assembly comprises a plurality of stacked stator laminations 73 mounted within a supporting ring member 74 which may have a pressed fit engagement on its outer surface with the interior of the casing part B. The stator assembly includes the usual windings as generally indicated at 75, which it will be understood may constitute individual coils assembledlin the grooves in the stator laminations 73 in. accordance with usual practice. In addition to the winding grooves, the stator laminations' are provided with a plurality of passageways 76 extending entirely through the stator laminations in an axial direction with ends opening on opposite sides of the stator.

Stator winding connections are brought out througha plurality of leads 77, each lead being connected with a sealed terminal connector which includes a bolt 78 supported within an opening 79 of the end wall of the casing part B. The head of the bolt is insulated by insulating members 80 from the adjacent casing part, and the shank portion of the bolt, where it passes through the wall of the casing, is insulated by a tubular insulator 81. A clamp spacer member 82 of suitable insulating material surrounds the projecting threaded end of the bolt 78 and is held in tight engagement with the adjacent casing material by means of a securing nut 83 which is tightened against a washer 84 disposed between the nut and spacer member.

It will be apparent from the foregoing description that by mounting the stator in the casing part B and by making this a unitary assembly which may readily be disconnected from the casing part A of the motor-compressor unit, it becomes a very easy matter to replace a burned out or otherwise damaged rotor winding in the field with a replacement assembly, without the necessity of having to use special tools to get at and remove the damaged parts.

Above the electrical terminal connectors, the wall portion of the casing part B is provided with an inlet 85 adapted for connection with a conduit for returning Tefrigerant and any oil particles or slugs of oil which may be contained therein back to the motor-compressor unit.

The returning refrigerant and any oil particles contained therein enter the compartment 20 where contact is made with surfaces of moving and stationary parts of the motor assembly. In order for the refrigerant to reach the compartment 19, it is necessary for it to pass through the motor assembly, which it may do by flowing through the air gap between the rotor and stator, and also by passage through the passageways 76 of the stator laminations. The oil particles in the refrigerating fluid will be separated out and returned to the bottom of the easing and the oil and refrigerant will further act as a cooling medium for cooling the motor parts. The refrigerant then passes into the compartment 19 and from there may again be sucked into the cylinders and compressed, and started on another refrigerating cycle.

I claim as my invention:

1. In a fluid compressing unit having pumping elements therein: walls forming a head chamber for collecting pumped fluid; valve means in said chamber for controlling discharge of fluid from said pumping elements; an imperforate dished cover in said chamber positioned over said valve means with its edge seated on a wall of said chamber to oppose flow of pumped fluid from said valve means into said head chamber; and spring means acting against said cover normally biasing it in a seating direction, but enabling unseating in response to increased fluid pressure under said cover, so as to enable flow from said valve means into said collecting chamber.

2. In a fluid compressing unit having fluid cylinderpiston pumping elements and a plurality of outlet valves: walls including a cylinder head member defining a chamher for said valves and for collecting pumped fluid; an imperforate dished cover in said collecting chamber over said valves with its brim adapted to seat on a wall surface in said collecting chamber and form a fluid receiving chamber for initially receiving the fluid discharged from said pumping elements through said valve means; and means normally biasing the cover to seated position, but enabling raising movement upon increased pressure thereof.

3. The combination with a valve mechanism mounted in a cylinder head wall of a fluid compressing unit, of a dished imperforate cover positioned over the valve mechanism to muflle its operating noises, said cover having an offset brim edge forming a valve part adapted to seat on said wall; and spring means acting against the exterior of said cover normally biasing it in a direction to seat said brim edge on said wall, but enable unseating in response to increased fluid pressure under said cover.

4. The combination in a fluid compressing unit, of a valve mechanism supported in one Wallof a cylinder head valve compartment defined by a plurality of walls, a dished imperforate cover for the valve mechanism positioned thereover, said cover having an offset brim edge adapted to form with said one wall, parts of a valve in series flow relation with said valve mechanism in a radial direction; and elongate strap springs secured in spaced relation on the exterior of said cover, the ends of said springs being adapted to bear against another wall of said valve compartment and bias the cover in a direction to seat its brim edge on said one wall.

References Cited in the file of this patent UNITED STATES PATENTS 943,544 Hensley Dec. 14, 1909 947,431 De Grandsagne Jan. 25, 1910 1,628,096 \Vorth May 10, 1927 1,665,871 Wood Apr. 10, 1928 1,736,635 Steenstrup Nov. 19, 1929 1,807,512 Culp May 26, 1931 1,889,122 Hewitt Nov. 29, 1932 1,915,694 Reindel June 27, 1933 2,043,215 Smith et a1. June 2, 1936 2,140,328 Mozier Dec. 13, 1938 2,222,703 Bixler h Nov. 26, 1940 2,235,962 Hormady Mar. 25, 1941 2,283,024 Wolfert May 12, 1942 2,327,810 McAverney Aug. 24, 1943 2,435,108 Touborg Jan. 27, 1948 2,452,807 Thompson Nov. 2, 1948 FOREIGN PATENTS 602,226 Germany Sept. 5, 1934

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