US1949505A - Unitary motor-compressor - Google Patents

Description

March 6, 1934. J. A. WARREN 1,949,505

UNITARY MOTOR COMPRESSOR Filed Aug. 19, 1929 s Sheets-Sheet 1 INVENTOR. Jssp/zA WA KEEN ATTORNEY. 7

March 6, 1934- J. A. WARREN 1,949,505

UNITARY MOTOR COMPRESSOR Filed Aug. 19, 1929 3 Sheets-Sheet 2 INVENTOR. fosePH/l WARREN.

ATTORNEY March 6, 1934.

J. A. WARREN UNITARY MOTOR COMPRES SOR Filed Aug. 19, 1929 3 Sheets-Sheet 3 ATTORNEY.

Patented Mar. 6, 1934 PATENT OFFICE I UNITARY MOTOR-COMPRESSOR Joseph A. Warren, Mount Vernon, N. Y., assignor, by mesne assignments, to Frigidaire Corporation, Dayton, Ohio, a corporation of Delaware Application August 19, 1929, Serial No. 386,779

2 Claims.

This invention relates to improved unitary motor-compressors used in mechanical refrigerators and for other purposes.

Hitherto in the operation of compressors in 'I mechanical refrigerating machines and else-.

' addition, cast metal parts have been required.

in order to secure rigidity in the operating structure, which added greatly to the manufacturing and shipping costs.

It is the object of thisinvention to provide 'a compressor with an enclosed motor, in which the,

means for recovering the lubricant which drains into the motor housing is simplified and perzo fected.

A further object of this invention is to provide a stamped and drawn construction of the enclosing metal parts of the apparatus, in order to simplify its assemblage and reduce the shipping weight, and is adapted to hold the refrigerant without leakage.

I accomplish these and other desirable objects by providing a compressor or pump and a driving motor positioned within a gas tight chamber or chambers and associated inoperative relation with any suitable condensing and expansion members, or a separating chamber.

It will be readily understood that the preferred adaptations of this invention are described mere- 1y by way of example in this specification and illustrated in the drawings, and that the underlying principles are susceptible of incorporation ina variety of devices without departing from the spirit and scope of the invention.

In the drawings, like numerals refer to similar parts in parts of the several views, of which:

Fig. 1 is a view, partly diagrammatic and partly detailed showing a machine embodying my improved method of oil recovery, associated with a refrigeration circuit.

Fig. 2 is a modification of Fig. 1 shown in part.

Fig. 3 is a view showing my improved motor housing.

Fig. 4 is an end view of the motor supports with 5 housing removed. Fig. 5 is a view similar to Fig. 3 in which the motor supports are shown in modified form.

Fig. 6 is an end view of the motor supports shown in Fig. 5, the housing being removed.

Fig. 7 is a view of my improved method of oil recovery when used for other purposes than refrigeration, and also shows the pump shaft extended and carrying the rotating member of the motor.

In Fig. 1 there is shown the mechanical unit of a refrigeration system in conjunction with a diagrammatic representation of the conventional features of the condenser and evaporator members. This unit comprises a pump or compressor casing 1, a motor casing 2, and an intermediate 65 supporting member or base plate 3, to which the several casings are secured in a manner to be more fully described hereinafter. Positioned within the pump casing is the compressor, designated generally by the numeral 4. The compressor is secured to the supporting member by any suitable means, not shown, as this feature is not claimed as a part of the present invention, and is shown merely for the purpose of facilitating the understanding of the cooperative action of the various parts of the unit.

Shaft 5 of the pump is supported in a bearing 3 in the base plate and in the bearing 6 of the bossed end plate 7. The end plate may be formed separately and secured in pressure tight relation to the compressor body by any suitable means, such as welding or the like, or it may be formed integral therewith, such construction being wellknown to those skilled in the art. The shaft is hollowed throughout its length, as shown dotted at 8, forthe purpose to be described later. It engages the shaft 9 of an electric motor mounted in the motor chamber, the rotor being designated by the numeral 10, and the stator by the numeral 11. As shown,.the motor is of the squirrel cage type, but it will readily be apparent that any suitable motor may be used. The free space within the motor casing is designated generally by the numeral 12.

The motor shaft is supported in the bossed bushings 13 and 14 of the base plate and the motor casing respectively, and is in alignment with the compressor shaft, being, for all practical purposes, a continuation or extension thereof.

As noted previously, the motorcasing and the compressor casing are secured to the base plate in such a manner as to insure a tight fit throughout and form gas-tight housings for the motor and compressor, except for the openings 15 and 16, which will be described later, and such leakage as occurs at the motor shaft bearings. The respective housings are susceptible of being removed without trouble, thereby facilitating inspection and repair of the mechanical parts of the device.

The pump is provided with a suction or inlet pipe 17, and an outlet or discharge pipe 18, discharging into the chamber 19 formed by the compressor casing. Within this casing, a suitable lubricant, such as oil, is provided in such quantity as to nearly submerge the pump, the level of such body of lubricant being designated generally at 19. Pipe 20 projects downwardly from the compressor into the body of the lubricant, as shown at 21, and is in fluid communication with the hollow pump and motor shafts. The motor shaft is provided with a plurality of apertures 22, 23, which afford fluid communication between th inside and outside thereof.

In operation, the pressure being equal in the pump chamber 19 and the free space in the motor casing 12 the oil or other lubricant flows up through pipe 20 and into and through the hollow shafts of the compressor and motor, whence it escapes through ducts 22, 23 and bushings 22 23" lubricating the bearings, the surplus oil or 7 other lubricant passing into the motor chamber 12. Hitherto the removal of such deposited lubricant from an enclosed motor chamber has been,

accomplished with diiiiculty and has afforded a much trouble in the operation of the motor, special means being required to collect and recover the lubricant and return it to the pump chamber. Such special means is obviated by the practice of my invention wherein the bottom of the motor housing is sloped as shown at 24, to form a drain toward the outlet 16.

Opening 15, above referred to, serves to permit the escape of the refrigerant gas into the motor chamber. This gas is comparatively free from lubricant due to the compression it has been subjected to in the pumpv and because the gaseous refrigerant distills off from the lubricant when contacted with hot walls of the pump and pump chamber.

The gas is now in the upper portion of the pump chamber and in the motor chamber and has only one point of egress, namely the motor chamber outlet 16. Any oil which has been forced through the motor bearings will collect in the bottom of the motor chamber and will flow along with the refrigerant gas through the motor chamber outlet 16, and into the condenser 25.

The condenser is cooled in any suitable manner, as-by a current of air forced therethrough by a motor driven fan 26, although any appropriate cooling medium may be used, and such means is readily apparent to those skilled in the art. The gaseous refrigerant is liquefied in the condenser and passes through pipe 2'? along with the lubricant, both being forced by positive pressure being imparted to the fluid by the pump, intothe expansion valve 28, which may be of any well known construction. The refrigerant slowly passes through this member along with the lubricant and through conduit 29 into the expansion chamber 30, where it absorbs heat thereby cooling the chamber. The expansion chamber may be of any suitable construction, and forms in itself no part of the present invention. The expanded refrigerant along with the lubricant is drawn from this chamber through pipe 30 through suction inlet pipe 17 and into the pump 4 when it is recompressed passing through pipe 18 into pump' chamber 19 where the lubricant is separated from the refrigerant as before described.

Figure 2 is a modification of Fig. 1 in which pipe 31 is carried from opening 15 to a point adjacent to opening 16. The compressed refrigerant passing from pipe 31 into opening 16 acts as an" aspirator and tends to accelerate the flow ofany oil or lubricant which has collected in the bottom of motor chamber 24.

As already indicated, the pump casing and the motor housing must be gas tight, and while it is obvious that the pump casing may be made of stamped or drawn material, the motor housing presents a special problem. As shown and described, the motor housing or casing 2, is of cast metal, the use of such heavy and costly construction being necessitated by the fact that the motor shaft is supported in the bossed, bushing of the casing and the corresponding member of the base plate and'they must be possessed of sumcient rigidity and strength to withstand. the vibratory stresses set up when the motor is operated. In addition to the inherent disadvantages of weight and high costs of manufacture, such castings are rarely gas tight.

. To avoid this disadvantage and to secure added economies in manufacturewithout in any way sacrificing the desired features of my improved device, I have provided a novel construction of the motor and its associated housing. This modification is shown in its essential details in Figs. 3 and 4, and will be described with particular reference thereto.

I The intermediate supportingmember of the unit is provided with a plurality of bosses 32, equally spaced from the shaft supporting central bushing 13. The bossesare tapped as shown at 33 to receive threaded bolts 34 provided with headed portions 35 of any suitable configuration. The bolts are passed through suitable apertures in a, spider 36 and the stator 11 of the motor, and are threaded into the bosses 32. The spider comprises a plurality of arms integral with and radiating from a central nember or boss 37 and terminating in apertured bosses 38, The central boss is apertured to form a socket or bearing 39 for the motor shaft. If necessary, a plurality of bushings 40 may be interposed betweenlthe bosses and the stator 01' the motor in order to assure the correct alignment of the motor shaft in its bearings when the various parts are secured together by fastening the bolts in place. This construction provides a simple. yet efficient means of associating the motor parts in cooperative relatonship and obviates the necessity of using heavy cast housings with their inherent defects and high manufacturing costs.

To provide a housing for the motor chamber, a stamped or drawn metal cup or member ,41 is made use of. This housing is provided with a flanged portion 42 which is secured to the central supporting member by means of a plurality of headed bolts 43 tapped into the supporting member. The lower part of the housing is sloped as shown at 24 to permit drainage of the lubricant towards the outlet 16*. Any suitable sealing means may be interposed between the several housings and the central support in order to assure a gas tight fit throughout the unit.

In lieu of securing the spider in place by means of the threaded bolts passing through the stator, I contemplate, as an optional design feature, providing the spider arms with integral exten sions formed at right angles to the plane of the arms. These extended arms are flanged at 45 and secured to the central supporting member or base plate by any suitable means, such as threaded bolts 46. The arms are drilled to receive set screws 47 for securing the stator in its proper 150 above noted. 115 I position. This construction is shown in detail in Figs. 5 and 6.

Fig. 7 shows a further modification of my invention wherein the intermediate supporting member or base plate 3, has a projecting portion- 48, concentric with bushing 13, which encircles and supports stator 11. This projecting portion can be made integral with plate 3 or can be attached thereto by bolts, screws or other method known to those versed in the art. The shaft 5 of the pump is extended so as to pass through and support rotor 10 which is rigidly secured thereto by nut 49 and key 50. This method of construction eliminates the necessity of bushing 37 as shown in preceding figures.

It also shows my improved method of oil recovery when the motor compressor is used for compressing air or gas, the method being the same as shown and described in Fig. 1 except that when the gas and oil passes through opening 16, it enters pipe 51, which in turn delivers it into chamber 52 where the oil is separated from the gas and passes through pipe 53 and back to the body of oil in chamber 19, the gas passing out through opening 54.

It will now be appreciated that I have provided an improved motor-compressor unit of a mechanical refrigerating apparatus and other purposes which permits the ready withdrawal of the lubricant from the motor chamber, and one in which the motor and compressor housings are formed of drawn or stamped metal, thereby avoiding the inherent disadvantages of cast members, while appreciably lessening manufacturing and assembling costs.

While I have herein shown and described preferred embodiments of my invention, it is to be understood these are merely for purposes of exempliflcation, for since the underlying features may be incorporated in other specific mechanical structures, I do not intend to be limited to the ones shown, except as such limitations are clearly imposed by the appended claims.

I claim:'

1. In combination, a pump having an inlet and an outlet, a body of lubricant for lubricating said pump, a motor connected thereto, a casing enclosing the motor and being under the pressure of the outlet of said pump, an outlet from the casing, means for lubricating the motor bearings from said body of lubricant, said last named outlet being positioned to receive the drainage of excess lubricant from the casing and to remove it by the discharge pressure generated by the pump, means for relieving the pressure on said lubricant and means introducing it at the inlet of said pump.

2. In combination, a pump having an inlet and an outlet, a body of lubricant for lubricating said pump, a motor connected thereto, a casing enclosing the motor and being under the pressure of the outlet of said pump, an outlet from the casing, means for lubricating the motor bearings from said body of lubricant, said last named outlet being positioned to receive the drainage of excess lubricant from the casing and to remove it by the discharge pressure generated by the pump, a condenser having fluid connection with said pump and receiving the drainage of lubricant from said last named outlet, an evaporator connected to said condenser, said evaporator having its discharge connected to the inlet of said pump.

JOSEPH A. WARREN.

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