US2420442A - Sealed motor compressor unit for refrigeration apparatus - Google Patents

Description

y F. RATAICZAK 2,420,442

SEALED IOTOR COMPRESSOR UNIT FOR REFRIGERATION APPARATUS Filed April 26, 1943 s Sheets-Sheet 1 May 13, 1 947. F. RATAICQZAK V SEALED MOTOR COMPRESSOR UNIT FOR REFRIGERATION APPARATUS Filed April 26, 1943 s sheets-sheet 2 y 1947 A F. I. RATAICZAK I 2,420,442

SEALED IOTOR COMPRESSOR UNiT FOR REFRIGERATION APPARATUS Filed April 26, 194:: a Sheets-Sheet 3 Patented May 13, 1947 SEALED MOTOR COMPRESSOR UNIT FOR REFRIGERATION APPARATUS Francis I. Rataiczak, Dayton, Ohio, assig'nor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application April 26, 1943, Serial No. 484,543

8 Claims. (Cl. 62-115) This invention relates to refrigerating apparatus and more particularly to an improved motor compressor unit and refrigerant circuit.

It is an object of this invention to provide a refrigerating system wherein the main motor compressor housing serves as a, lubricant separating and storage chamber.

Another object of this invention is to provide a refrigerating system in which the superheat is removed from the compressed gas before being discharged into the lubricant separating chamber.

A further object of this invention is to provide an improved arrangement for cooling the motor compressor unit.

More particularly it is an object of this invention to improve upon the compressor design so as to facilitate the renewal of the hot compressed refrigerant vapor from the compressor without flowin the compressed vapor in thermal exchange with the motor compressor assembly.

A still further object of this invention is to simplify the motor compressor design.

Another object is to reduce the number of dies required in the manufacture of several different capacity compressors.

Further objects and advantages of thepresent invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

in the drawings:

Fig. 1 is an elevational 'view, partly diagrammatic and with parts broken away, showing a preferred form of my invention;

Fig. 21s a, vertical sectional view showing one oi the steps in assembling the motor compressor unit;

Fig. 3 is-a fragmentary sectional view;

Fig. 4 is a top view of the outlet valve assembly;

Fig. 5 is an elevational view with parts broken away of the outlet valve assembly;

Fig. 6 is a fragmentary sectional view showing the location of the outlet valve assembly with respect to the outlet port and the compressor mounting block;

- 2 Fig. 9 is a top view of the motor compressor unit with the motor rotor broken away; and

Fig. 10 is a fragmentary perspective view showing the motor stator mounting member.

Referring now to the drawings and particularly to Fig. 1, reference numeral l2 designates a substantially cup-shaped casing element within which the motor compressor mechanism is mounted. Reference numeral M designates a cover plate which is welded or otherwise secured to the upper end of the cup-shaped casing element l2. Reference numeral l6 designates generally the compressor assembly which is mounted on a plurality of blocks l8 and I9 carried by the bottom wall of the casing element l2. The compressor is a rotary compressor which includes a cylinder element 20 sandwiched in between the end plates 22 and 24. An impeller 26 is disposed within the cylinder 16 and is operated by means of the eccentric 28 provided on the main shaft 36. A divider block 32 is provided in the one wall of the cylinder as best shown in Figs. 3 and 7. The divider block 32 is biased into engagement with the impeller 26 by means of a spring 3 5 which is held in place by means of the spring retainer 36. The cylinder element 28 is providedwith a pair of slots 38 (Figs. '7 and 8) within which the arms of the spring retainer 36 engage. The shape of the slots 38 is such that thespring retaining element 36 may be assembled by sliding the spring retainer downwardly into position. The upper end plate 25 is provided with slots 60 which are somewhat similar in shape to 24 as shown in Fig. 8.

Fig. '7 is a horizontal sectional view taken The bottom end plate 22 is provided with an inlet port 42 and an outlet port M arranged as shown in Figs. 3 and '7. An inlet check valve assembly 4B is held in place within the mounting block l9 by means of the end plate 22. An outlet check valve assembly 48 is held in place within an elongated recess 50 provided in the end plate cant to the bearing surfaces.

22 as shown in Fig. 6. The inlet check valve is similar in construction to the inlet check valve more fully described in my Patent No. 2,395,065, February 19, 1946. v

The outlet valve assembly comprises a cylindrical frame or cage 52, the ends of which are inturned as at 54 and 56 so as to form abutments for the spring element 56 and the check valve plate 60. The walls of the cylindrical frame 52 are slotted as shown at 62 (Figs. 4 and 5) so as to form outlet passages for the compressed gas. The valve assembly 48 is arranged adjacent one end 64 of the elongated recess 50 provided in the end plate 22 (Figs. 3 and 6). The recess 50 is provided with an enlargement 66 as shown in Fig. 6 whereby the compressed refrigerant leaving through the slots 62 is free to escape into the main recess or chamber 50 from whence it flows downwardly through the passages 68 provided in the mounting block IS. The passage 68 leads to the refrigerant line 19 which conveys the compressed refrigerant together with the entrained lubricant to the superheat removing coil II. The coil II is supported by means of a basket 13 secured to one of the heat dissipating fins 15 as shown in Fig. 1.

Themotor stator 69 is supported within the cup-shaped casing element I2 by means of a corrugated mounting strip 10 which is welded or otherwise secured to the walls of the cupshaped casing l2. The motor stator engaging surfaces of the strip 10 may be trued up by a sizing die which deforms the material where necessary. As shown in Fig. 2 the mounting strip 10 is provided with inturned tabs 12 adjacent the bottom thereof to limit the downward movement of the compressor stator- After the motor stator has been inserted in place, the tabs 14 are bent over as shown in Figs, 9 and 10 so as to hold the motor stator in place. The tabs 16 assist in guiding the motor stator during assembly.- Thus the one sheet metal stamping Hi not only serves to hold the motor stator in place but also assists in guiding the stator as it is lowered into place.

As explained hereinabove the super heated gas and the entrained lubricant leave the compressor through the outlet line I9 which is connected to the super heat removing coil H. The mixture of compressed gas and lubricant flowingthrough super heat removing coil H is returned to the motor compressor compartment through the line 18 (see Fig. 1). The primary purpose of the coil H is to remove some or all of the superheat. The lubricant entrained by the refrigerant gas separates out from the refrigerant gas in the motor compressor compartment and the substantially lubricant-free compressed refrigerant leaves the casing through the outlet line 80 which leads to the main condenser 82. The lubricant thus separated out from the refrigerant drains down into the lower portion of the cup-shaped casing l2 so as to supply lubricant to the compressor as needed. The compressor shaft 30 is provided with the usual form of oil feed grooves 84 and 66 as shown in Fig. 1 which supply lubri- By virtue of the corrugated construction of the motor stator mounting strip I0, it is obvious thatlubricant separated out from the refrigerant is free to flow downwardly between the motor stator 69 and the casing portion [2.

The refrigerant which is condensed in the condenser 82 collects in the receiver 90 from which it is supplied to the evaporator 92 in accordance with well-known practice. The flow of refrigerant from the receiver 66 to the evaporator 92 may be controlled by means of any conventional control device such as a thermostatic expansion valve or a fixed restrictor 64. The refrigerant vaporized in the evaporator 92 returns to the compressor through the suction line 96 which communicates with the inlet valve assembly 46 adjacent the inlet port 42.

The mounting block I9 serves several purposes in that the incoming low pressure refrigerant from line 96 passes through the block I! and the outgoing compressed refrigerant leaves through the block l9 and refrigerant may be added to the system through the charging plug 98 which is also carried by the mounting block l9. As shown in Fig. 3 the charging plug is provided with two passages 91 and 99 which lead to the high and low sides respectively of the refrigerating system. The cap I M normally closes the outer ends of the passages 91 and 99 but uncovers the passages when rotated so as to permit the addition of lubricant or refrigerant to the system.

In order to simplify the assembly of the parts and in order to make it possible to use the same dies for several different sized motor compressor units, the outer diameter of the compressor elements 20, 22, and 24' is slightly less than the internal diameter ofthe motor stator. By virtue of this arrangement the compressor assembly may be inserted downwardly through the motor stator opening and secured in place by means of bolts As shown in Fig. 2 the arrangement is such that the compressor assembly may be shoved to one side so as to allow the divider block spring 34 and spring retainer 36 to be slipped into place after the main compressor assembly has been insorted into the bottom part of the cup-shaped casing l2. In Fig. 2 the spring retainer 36 is shown partially inserted, whereas in Fig. l the spring retainer 36 has been moved into operating position. The main cylinder 20 and the end plates 22 and 24 are assembled prior to their insertion into the casing l2. The bolts I02 hold these parts in assembled relationship while the parts are being slipped into place. For a given diameter compressor, the capacity may be changed by changing the thickness of the compressor cylinder without changing the end plates. Thus the same dies may be used for several sized compressors. In order to vary the capacity of the motor, the depth of the motor stator from top to bottom may be varied without requiring a completely new set of dies.

In positioning the compressor assembly on the mounting blocks l8 and IS a suitable positioning fixture (not shown) would be used which would accurately line up the bearing surfaces of the compressor assembly with the internal surfaces of the motor stator as fully explained in the above mentioned patent. By virtue of this arrangement the accumulation of permissible tolerance errors in the manufacture of the parts is avoided. The motor rotor I04 can be placed on the shaft 30 prior to the assembly of the shaft 36 with the rest of the mechanism whereby the outer surface of the motor rotor may be turned down to size using the same centers as were used in turning down the shaft 30. Thus any error in eccentricity or otherwise in the manufacture of the external surface of the upper end of the shaft 30 or the interior motor rotor could be com pensated for in turning down the outer surface of the motor rotor it.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. In combination means forming a compressor cylinder, end plates for closing the ends of said cylinder, a divider block slot in said cylinder, a divider block slidably mounted within said slot, spring means biasing said divider block inwardly, open keyways formed in the outer wall of said cylinder and arranged substantially parallel to the axis of said cylinder, keyways provided in one of said end plates having the axis thereof disposed inwardly of said first named keyways, spring abutment means in engagement with the outer end ofsaid spring means and including arms slidably downwardly through the keyways provided in said end plate and in said cylinder wall, said keyways and said arms being so constructed and arranged that upon insertion of said arms into the keyways in said cylinder the arms are locked in place by said end plate, a drive shaft rotatably mounted within the compressor cylin-' der, an impeller eccentrically mounted on said shaft and having contact at its periphery with the end of the divider block remote from the spring means, and fluid inlet and outlet ports for the compressor cylinder on opposite sides of the divider block.

2.. In combination, casing means forming a lubricant separating and storage chamber, a compressor within said chamber, a refrigerant superheat removing coil located outside said chamber, outlet means for said compressor for discharging compressed refrigerant into said superheat removing coil, an outlet from said coil discharging the partially cooled refrigerant into said lubricant separating and storage chamber, and an outlet from said chamber through which the compressed refrigerant is discharged.

3..In combination, casing means forming a lubricant separating and storage chamber, a mo tor compressor unit disposed directly within said chamber, an outlet from said compressor, a cooling' coil having an inlet connected to said compressor outlet and having an outlet communicating with said lubricant separating and storage chamber, and an outlet from said lubricant separating and storage chamber. I

4. In combination, a cup-shaped casing, a refrigerant compressor disposed within said casing,

a compressor mounting block projecting through the bottom wall of said compressor for supporting said compressor within said casing, said block having a. first passage for supplying low pressure refrigerant to said compressor and a second pas-- sage for conveying compressed refrigerant away from said compressor and out through the wall of said casing, said mounting block including a refrigerant charging means for simultaneously adding refrigerant to both the low side and the high side of the system including one passage communicating with said low pressure refrigerant passage and another passage communicating with said compressed refrigerant passage.

5. In a refrigerating system; a cup-shaped casing adapted to contain a supply of lubricant; a cover for closing the upper end of said casing; means providing compressor mounting surfaces carried by the bottom wall of said cup-shaped casing; means providing motor stator mounting surfaces carried by the upstanding wall structure of said cup-shaped casing; a motor stator carried by said second named means in engagement with said motor stator mounting surfaces; a compressor assembly having an external diameter slightly less than the internal diameter of said motor stator; means for securing said compressor assembly to said first named means in engagement with the mounting surfaces thereon; inlet and outlet ports for said compressor; a valve assembly held in place by said compressor assembly: said valve assembly comprising a valve plate for engagement with one of said ports, a spring for biasing the valve plate into valve closing position, and a substantially cylindrical cage having inturned ends for holding said valve spring and said valve tionship; a motor rotor; a shaft for mounting said motor rotor and for operating said compressor; means for conveying the compressed refrigerant leaving said valve assembly directly to the outside of said casing; a cooling coil connected to said refrigerant conveying means for removing superheat from the compressed refrigerant: means for flowing the refrigerant leaving said cooling coil into said cup-shaped casing so as to drop out the lubricant from the refrigerant; a condenser disposed outside of said casing; means for conveying the lubricant free refrigerant from said casing to said condenser; and means including an evaporator connecting said condenser and the inlet of said compressor.

6. In a sealed motor compressor unit; a cupshaped casing adapted to contain a supply of lubricant; a cover for closing the upper end of said casing; means providing compressor mounting surfaces carried by the bottom wall of said cup-shaped casing; means providing motor stator mounting surfaces carried by the upstanding wall structure of said cup-shaped casing; a motor stator carried. by said second named means in engagement with said surfaces; a compressor assembly; means for securing said compressor assembly to said first named means in engagement with the mounting surfaces thereon; inlet and outlet ports for said compressor; a valve assembly held in place by said compressor assembly and comprising a valve plate for engagement with one of said ports; a motor rotor; a shaft for mounting said motor rotor and for operating said compressor; means for conveying the compressed refrigerant leaving said outlet port to the outside of said casing; a coolingcoil connected to said-refrigerant conveying means for removing superheat from the compressed refrigerant; and means for flowing the refrigerant leaving said cooling coilinto. said cup-shaped casing so as to drop out the lubricant from the refrigerant.

7. In a refrigerating system, a condenser, an evaporator, casing means forming a lubricant separating and storage chamber, acompressor within said chamber, a refrigerant superheat re.-

moving coil located outside said chamber, outlet means for said compressor for discharging com- I pressed refrigerant into said superheat removing coil, an outlet from said coil discharging the partially cooled refrigerant into-said lubricant separating and storage chamber, an outlet from said chamber through which the compressed refrigerant is discharged into said condenser, and fluid flow connections between said condenser, evaporator and compressor.

8. In combination, a casing, motor compressor mechanism within said casing, a refrigerant su- 7 perheat removing coil located outside said casing.

plate in assembled rel'a- 8 UNITED STATES PATENTS outlet means for said compressor for discharging compressed refrigerant vapor into said superheat Number removing coil, an outlet from said coil discharg- 1 843,747 ing the partially cooled refrigerant vapor into 197,578 said casing, a condenser, an evaporator, means 5 1,890,205 for conveying refrigerant vapor from said casing 1,876,370 to said condenser, means for conveying the con- 2,013,521 densed refrigerant from said condenser to said 23945323 evaporator, and means for conveying the vapor- 2,152,056 ized refrigerant from said evaporator to said com- 10 55 7 D 2,185,631 FRANCIS I. RATAICZAK. 2 30 0 2,361,855 REFERENCES CITED The following references are of record in the 15 Numb er file of this patent. 687,416

Name Date Wilson Feb. 2, 1932 Jackson Sept. 5, 1916 Andresen Dec. 6, 1932 Weber Sept. 6, 1932 Heitman Oct. 22, 1935 Kenney et a1 Sept. 28, 1937 Kenney et a1 Mar. 28, 1939 Firestone et a]. Apr. 25, 1939 Heinze Jan. 2, 1940 Hubacker Dec. 29, 1942 McCormack Oct. 31, 1944 FOREIGN PATENTS Country Date Germany Jan. 29, 1940 Great Britain July 2, 1931

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