US2107630A - Refrigerating apparatus - Google Patents

Description

Feb. 8, 1938. F. R. ERBACH REFRIGERATING APPARATUS Filed Sept. 2l, 1932 5 Sheets-Sheet l 23a l t INVENTOR.

F'Reomem( I@ Eleam A TTORNEY.

Feb. 8, 1938.A F R- ERBACH y 2,107,630 I REFRIGERATING APPARATUS Filed sept. 21, 1932 5 Sheets-Sheet 5 4H4 l I-----' l 251 //5 i 7z I 1 7, g 1

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Feb. 8, 1938. F* R ERBACH 2,107,630

REFRIGERATING APPARATUS Filed Sept. 2l, '1932 5 Sheets-Sheet 4 l IZ . 45 INVENTOIL F 7. 7. el 60 Ptsoeglclc R- RIMM ATTORNEY.

Feb. s, 193s. F R ERBACH 2,107,630

REFRIG ERAT ING APPARATUS //5\ 4l F 5' INVENTOR.

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A TTORNE Y.

Petenied Feb. s, 193s PATENT OFFICE 2,107,630 l REFRTGERATING APPARATUS Frederick n. Erbach, Beloit, wie., assigner, by

mesne assignments, to Nash-Kelvlnator Corporation, Detroit, Mich., a corporation of Maryland Application September 21, 1932, Serial No. 634,129 1 claim. (ci. 23o- 139) A `further object is the provision of a simple and effective device for permitting the driving motor to substantially reach'its ,normal operate ing speed before any material load is placed on it.

Still another object of the invention is to provide a compressor of the pendulum rotary type having a radial abutment member rigidly attached thereto, which abutment member reciprocates between two oscillating members during the operation'of the compressor, the relationand operation of the parts and their coordination being such that a compressor of high eiliciency for gas compressing purposes is provided.

My invention also includes improved intake and discharge valve structures particularly designed for use` with a compressor of the type before mentioned.y

By this invention there is valso provided an improved lubricating system for an enclosed motorcompressor unit in which the lubricating medium is positively circulated through the -moving parts of the mechanism, circulated outside the enclosing casing and then cooled, and then returned to the casing in its "cooled state to assist in removing the heat generated by the motor and compressor during their operation.

Other objects and advantages of the invention will be apparent from the following description and accompanying drawings wherein:

Fig. 1 is a vertical view, partly in section, of a refrigerator cabinet showing my improved refrigerating mechanism in operating relation thereto. i

Fig. 2 is a 4vertical view partly in section through the-compression mechanism taken on the line II--II of Fig. 3 and showing diagrammatically its relation to the other parts of the refrigerating system.`

Flg. 3 is a vertical view partly in section of the compression mechanism and taken at a displacement of substantially 90 from the view in Figure 2.

Fig. 4 is a vertical sectional view on an en larged scale of the compressor proper, taken on the line IV-IV ofrFlg. 8.

Fig. 5 is a detailed view partly in section showing the connection of the oil return conduit to the compressor housing.

Fig. 6 is a plan view partly in section, taken von the line VI--VI of Fig. 3 and showing dctails of the compressor base and oil pump.

Fig. 7 is a fragmentary vertical sectional view taken on the line VII-VII of Figure 6 and showing further details of the oil pump and lubrication features.

Fig. 8 is a plan view partly in section of the compressor per se.

Fig. 9 is an enlarged vertical section taken on the line IX-IX of Figure 6 and showing details of the inlet and discharge valve mechanisms for the compressor.

Figs. l0, 11, 12, and 13 are detail views o1' component parts of the discharge valve mechanism, and i Flg.`14 is a vertical view, partly in section, and showing a preferred structure for making an electrical connection through the casing to the enclosed motor. l

Referring to the drawings wherein is shown a specic embodiment of the invention, I0 designates a refrigerator cabinet supported by legs I2 and provided with insulated walls II which together with a swinging insulated ydoor I3 form a food storage compartment I4. The refrigerating apparatus comprises generally a heat insulated base I5 which is removably supported, as by members I6 and thus forms a removable top wall for the food storage compartment I4. A heat-absorbing unit I1 is ilxedly secured lto and suspended from the base I5 within the food compartment. The heat-absorbing unit may be of any suitable construction but is here shown as a sheet-metal evaporator of the type described and claimed in the co-pending application of Ransom H. Beman, Serial No. 556,420 filed Aug. 11, 1931, and assigned to lKelvinator Corporation.

Mounted on the upper side of the base I5 and llocated within a machine compartment lI8 formed. integrally with the cabinet above the tached thereto may be bodily removed from the cabinet in a vertical direction.

mechanism is shown diagrammatically, it will beV noted that the said mechanism comprises the casing 21 within which is located a hollow float member' 29 operatively connected to a valve member 30, which valve member cooperates with a seat 3 I. The construction is such that when a predetermined quantity of liquid refrigerant is present within the casing 21, the float will lift the valve 30 from its seat and allow liquid refrigerant to ow at a reduced pressurethrough a conduit 32 to the cooling unit or evaporator f1. Here because of 'its relatively low pressure the liquid refrigerant boils and in so doing absorbs heat from the food compartment I4. The gaseous refrigerant is then drawn through a conduit I3 to the compressor where it is recompressed and the cycle repeated. A motor driven fan 34 may be provided to force air over the condenser coils 25 and thus assist in removing heat from the compressed refrigerant.

Preferably, the base of the compressor unit is provided with a plurality of flanges 25 having openings through which project bolts 2B, and springs 31 are located around these bolts between each flange and the base l5 whereby to resilient# ly support the encased motor-compressor unit.

An oil 'cooling coil 3l similar in construction to the condenser coil 2i is disposed beneath the condenser coil and in the path of air circulated by the fan 34. This cooling coil is connected to the upper part of the casing 23 by a conduit 39 .and to thelower part of the casing by a conduit 40,

for a purpose to be hereafter described.

Referring to Figure 2 wherein is shown in more detailed form the compressor and motor operatively assembled, 4I designates generally a base of relatively heavy material upon which are supported the compressor and its driving motor together with the surrounding casing 23. The casing 23 may be sealed to the base in any desired mannerrbut is here shown as provided with a strap 23a welded thereto and in which strap are provided at spaced intervals a plurality of loops 2lb through which bolts 23e may be inserted and screwed into the base 4I so as to maintain the casing 23'in fluid tight contact with the base 4 i, a grooved flange 4|a. being provided in the upper surface of the base 4I for receiving the lower edge' of the casing 23. The base 4I is substantially circular and the compressor shaft 42 extends vertically upward substantially at the center ofthe base. The lower end of the shaft runs 'on a thrust bearing 43 extending into a recess 44 formed in the base. The base is alsoprovlded with a recess 4l for receiving a plate 4i upon which plate rests the compressor cylinder 41. The opposite side of the compressor serves as a support for a substantially U-shaped member 4I which in turn supports the motor stator 4I. When these parts are assembled, the compressor cylinder 41. is rigidly fastened between the members 48 and 4l by means of bolts 5l, which in turn secure the whole assemblyto the-base".

The lower member or plate 4l is provided with a recess 5I which receives a bearing 52 formed on the lower end of the shaft 42, and the upper or U-shaped member 4l has formed therein, at its central part, a somewhat elongated recess 53 which serves as a surface for an upper bearing 54 also formed integrally with the compressor shaft. 'I'he portion $5 of the shaft extending upwardly from the second main bearing is somewhat reduced in diameter and has keyed thereto the rotor 56 of the motor 2l. The extreme upper end of the shaft is screw-threaded as indicated at 51 and a nut 58 engages the threaded portion to securely-clamp the rotor 56 between nut 58 and a shoulder 59 formed above the upper bearing 54.

Immediately below the recess 45, formed in the base 4i for receiving the plate 46, there is a smaller recess 60 within which is located a centrifugal oil pump Si rigidly attached to and driven by the shaft 42.

Referring to Figures 4 and 8 wherein are shown details of the compressor construction, it will be noted that the piston $2 for the compressor is circular in cross-section, and that it is eccentrically mounted on the shaft 42, through the intermediary of an eccentric member 6,3 formed integrally with the shaft. A radial abutting member or blade 64 is rigidly attached to the piston O2 by means of bolts 64a, whereby this member and the piston move as a unit. The radial member extends into a cylindrical recess U5 between two substantially semi-cylindrical oscillating portions The nstruction is such that when the shaft 42 is rotated, the piston i2 wl nutate and thus its outer surface will always have one point in contact with the wall of the cylinder, thereby squeezing any gas which may be ahead of the point of contact and compressing the same until it is discharged through the valve 01.

As the radial member or blade 64 is rigidly a'ttached to the periphery of the piston it will reciprocate between the semi-cylindrical members I6 and these members will in turn oscillate in the cylinder l5. It will be noted that the cylinder 6l is provided with narrow recesses 68 at diametrically opposite points so that there is a relatively small contact'surface between each of the semicylindrical members I and the remaining portion of the cylinder wall Si. By this construction I have not only reduced the bearing surface and consequent frictional loss but have also provided a means for eifeotually reducing any tendency on the part of the members to bindin the cylinder wall during the operation of the compressor.

The blade 64 serves as a constant partition be tween the high and low pressure sides of the compressor and eifectually prevents the escape of gas from one side to the other.

'Ihe intake valve 1B comprises a disc of spring steel 1I, firmly maintained seated by thev force of a spring 12 which surrounds a pin 1I rigidly fastened in the cylinder wall. The discharge or exhaust valve comprises a recess 14 formed in the upper member 4l and provided with a cover member 15 from which a relatively short conduit liaextends vertically upward. This conduit should, however, be long enough to extend at all times above the highest oil level obtainable with; in the casing 2l. The valve mechanism proper consists of an elongated seat member Il shown in Figure 12 and .provided with a downwardly depending hollow cylindrical portion projecting into the discharge port 11 in a tight. relation. 0n its upper surface this member is provided with a relatively narrow upwardly projecting seat 1I .nommant mitnimmt...raamt.t

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and is then cut away as indicated at 19 to provide a groove for receiving a small quantity of oil which assists in quieting the action of the valve. The valve member which cooperates with the seat 18 comprises a flat leaf spring 88 shown in Figure 10. It will be noted from this figure that the portion of the spring engaging the valve seat is substantially circular in form and that from the circular portion a somewhat narrow neck extends to an enlarged portion 8|. In Figure 13 there is shown a second leaf spring member 82 substantially rectangular in contour and provided at its outer end with an opening 82a for a purpose to be hereafter described.

Referring to Figure 9, it will be noted that the valve member 88 is mounted directly on the valve -seat, that the member 82 is superposed thereon in a slightly spaced relation, and is so maintained by an interposed washer 83, and that a rigid Z-shaped member 84, is superposed on the member 82 with a portion 85 overhanging the valve seat and spaced some distance therefrom. A

stud 86 is rigidly fastened to the underside of L sure be exerted on the valve member 88 such as might be caused by the passage of a slug of oil, the4 construction is such that the member 8|), the spring 86 and the spring member 82 will all yield and allow the pressure to be relieved.

The lubrication of the moving parts of the motor and the compressor is accomplished by a. forced lubrication system in which the circulation of oil is maintained by the pump 6|. As has been previously stated this pump is located in a recess 68 formed in the lowermost portion of the casing 4| and is directly attached to and driven by the main compressor shaft 42. The oil -pump may be of any desired construction but as here shown. is a conventional centrifugal pump. Under normal operating conditions, the casing 23 contains a body of oil to a level indicated approximately by the line 88, Figure 2. Thus it will be noted that the compressor mechanism is completely immersed in an oil bath and that the level of the oil terminates just below the lower part of the stator windings. When the motor and consequently the oil pump is operated, a. considerable .portion of the oil circulates out through passage-way 89v and through the conduit 48 to the oil cooling coil 38, where its temperature is materially reduced, and then returns through conduit 39 to the upper part of the casing 28. As the cool oil comes into the casing it is deflected from the stator windings by means of a shield 98 rigidly attached to the stator and' flows down Vthrough the space between the outer surface of the stator and the casing23 and in so doing, absorbs a considerable portion of the heat generated in the motor.` The oil then returns to the main body where itabsorbs additional heat from the compressor and is then re-circulated through the cooling coil by the pump.

Another portion of the oil flows through filter 9|a and passage-way 9|, Figure 7, to the lower shaft bearing 52, and is then forced into the compressor where it effectually seals the moving parts including the piston 62, the partition member or blade 64 and the two rocker members 66. It will be noted that, each of the at surfaces of the two rocker members adjacent to the blade 64, is provided with a recess 92 for permitting the introduction of loil between the plate and the rockers. Some of the oil also passes through ports 93 drilled through the eccentric 63 and from there passes to the upper surfaces of the compressor and then through grooves 94 formed in shaft 42 so that the upper bearing 54 is effectively lubricated. 'I'he oil then passes out over the upper edge of the bearing and drops down to the main body of oil the discharge valve and conduit 15a, will separate by gravity after they have passed through that conduit.

During the operation of the blade member 64 it is inevitable that a quantity of oil will constantly be trapped between the end of this blade and the cylinder casing in the space 9]. In order to prevent this trapped oil from exerting an increased pressure on the end of the blade and consequently adding to the load on the compressor a port 98 is drilled through the cylinder casing and connects the space 81 with the main body of i oil. This port is made of 4relatively small diameter so that while oil may pass freely from the space 81 to the main reservoir 4because of `the pumping effect of the blade 64, it will not readily flow in the reverse direction that is from reservoir toward the blade.

In order to permit the motor to attain approximately its normal operating speed before anyv load is imposed on it by the pumping action of the compressor, I provided an unloading device indicated generally by the numeral 99, and attached to the upper end ofthe compressor shaft. This device comprises a hollow cylindrical body |88 having a port |8| in one of its vertical end walls', and having an adjustable closure nut |82 screw-threaded into the opposite wall. A piston |83 is somewhat loosely mounted in the cylinder |88 and carries at its outer end a valve |84 adapted to cooperate with the port |8|. A spring |85 is interposed between the wall carried port 8| and the piston |88, the arrangement being such that when the machine is at rest, the spring will unseat the valve |84. The unloading device 99 is attached to the compressor shaft by means of a screw threaded boss |86. 'Ihis boss is provided with a hollow passageway |81 opening directly into a second hollow passageway |88 extending4 axially throughout the entire length of the compressor shaft 42.

A passage-way |89 is provided in the base 4| for the passage of low pressure gas from the cooling unit to the compressor.

'I'his passage-way. opens into a chamber ||8 in which is located a.

extending through the compressor shaft. Thus when the compressor is at rest, and the unloader valve |04 is unseated, there is an equalization of. the pressure between the interior of the casing 23 when the pressure corresponds to that of the compressor discharge through the port Ill, passage-ways |01 and |08, passage-Way 98 and the suction side of the compressor. When the motor is started it is necessary for it to attain a speed suicient to cause seating of the valve member |04 through the centrifugal force acting on the piston |03 and against the tension of spring |05 before this by-pass is closed, and as a result the motor will operate under a substantially no-load condition until it has substantially attained its normal operating speed. l

In Figure 14 I have shown one arrangement for carrying the lead-in connections for the motor through the casing 23. The number of these connections will of course vary with the type of motor used. The connecting means here shown comprise a screw threaded bushing ||4 of an insulating material such as phenolic condensation product, having an electrical conductor i|5 passing axially through and maintained against axial movement in the bushing by means of a flange I6 securely embedded in the insulating material,

In the operation of my device the liquid refrigerant in the evaporator or cooling unit I1 being under low pressure, boils and absorbs heat from the food compartment I4. The gaseous refrigerant is then drawn through conduit 33, passage-way |09, iilter passage-way ||2 and intake valve 'l0 to the suction side of the compressor. Here the gas is compressed by the rolling motion of the piston 62 against the cylinder wall, this motion being in a clock-wise direction as shown in Figure 8. As the volume of the gas is reduced its pressure is increased and it nally passes out through the passage-way 11, discharge valve 80, chamber 14 and conduit 15a to the interior of the casing 23. compressed gas passes through the conduit 24 to the condenser coil 25 where it is cooled and liquefied bythe air current created by fan 3l. The liquefied as then passes tothe float valve assembly 21 from which place the liquid re From this casing the frigerant is delivered at a reduced pressure through the conduit 32 back to the cooling unit I1. In the meantime, as has been previously explained in detail, a portion of the hot lubricating medium passes out through conduit Il, through the cooling coil 38 where a substantial portion of its heat is removed, and back through conduit 39 to the upper part of the casing 23. It is then deflected over the outer portion of the stator windings absorbing heat therefrom and then returns to the main oil reservoir where it absorbs further heat before being re-circulated outside the casingby the oil pump 6|. Thus it will be seen that I have provided a unitary cornpact refrigerating system employing a compressor of the rotary pendulum type in which the parts are so correlated as to produce a maximum eiliciency and simplicity of operation and which may be quickly and rapidly assembled or disassembled.

The lubricating system is both thorough and positive in its action, and in addition, the lubrieating medium is used as a means to assist in removing the heat of compression outside the enclosed casing.

My unloading device as shown and described because of its simple construction, has proved to be very effective and positive in its action.

While I have shown and described a specific embodiment of my invention, it will be understood that other forms might be adapted by coming within the scope of the appended claim.

I claim:

A compressing system comprising a base, a compressor, a motor mounted thereon, a casing enclosing said compressor and motor secured to said base, a body of lubricant disposed in said casing, and adapted to function as a lubricant sealing means and cooling agent, and means for pumping and conducting said lubricant outside of said casing for cooling said lubricant and then conducting said lubricant to the upper portion of the region in said casing where a portion of said cooled lubricant is directed over the motor windings and the remainder of said lubricant valong the inside surface of said casing.

FREDERICK R. ERBACH.

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