US2095009A - Refrigerating apparatus - Google Patents

Description

Oct. 5, 1937.

Or inal Filed May 10, 1932 A. PHILIPP 2,095,009

REFRIGERATING' APPARATUS 2 Sheets-Sheet l 1NVENTOR.: g mamw 4. P/I/A ATTORNEY.

Oct. 5, 1937. 1.. A. PHILIPP 'R-EFRIGERATING APPARATUS Original Filed May 10, 1932. 2 Sheets-Sheet 2 INVENTOR Lav/ ams 1?. P/(M/PP i ATTORNEY.

Patented Oct. 5, 1937 REFRIGERATING APPARATUS Lawrence A. Philipp, Detroit, Mich, assignor, by

mesne assignments, to Nash-Kelvinator Corporation, Detroit, Mich., a corporation of Maryland Application May 10, 1932, Serial N0. 610,472 Renewed November 11, 1936 4 Claims.

This invention relates to refrigerating apparatus and more particularly to an apparatus for and a method of maintaining a number of different refrigerating compartments at different temperatures.

Heretofore it has been the practice to maintain a temperature differential between a number of different refrigerant evaporators by means of pressure responsive valves associated with some familiar with the operation of the system. This causes abnormal operation of the system. In addition, the valves are usually complicated and expensive to manufacture. Also, in systems of this type, refrigerant vapor was frequently drawn into the compressor at the low pressure existing in the evaporator operating at a lower tempera ture than the others in response to a demand for refrigeration by that evaporator. This low pressure vapor was then compressed to its condensing pressure. Under these 'conditions, the compressor was required to do more work than it would if the refrigerant to be compressed was at a higher pressure.

One of the objects of my invention is to provide an improved and simplified arrangement for maintaining a number of different compartments at different temperatures.

Another object of my invention is to provide an improved method of refrigerating a number of different compartments at different temperatures.

Another object of my invention is to provide an improved and simplified arrangement for maintaining a nuniber of different compartments at a number of different temperatures by means of a multiple suction pressure compressor and to control the operation of the compressor in response to the changes in conditions in the evaporator which operates at the higher temperature.

'Another object of my invention is to provide for refrigerating the aforesaid compartments at different temperatures by means of a number of different refrigerant evaporators, and to arrange for compressing the refrigerant evaporated in said evaporators at a pressure corresponding substantially to that of the pressure existing in the evaporator which is operated at the higher temperature.

Another object of my invention consists in providing a compressor with a plurality of fluid suction ports whereby the fiuid to be compressed is drawn into the compressor at difierent times during the suction stroke of the compressor.

Another object of my invention consists in the provision and adaption of a rotary compressor for operation at a plurality of suction pressures and the simultaneous compression of the fluid received at different suction pressures.

Further objects and'advantages of the present 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 a diagrammatic representation of a refrigerating system embodying features of my invention;

Fig. 2 is a diagrammatic representation of a modified form of refrigerating system embodying features of my invention;

Fig. 3 is a side view in cross section of a motorcompressor unit embodying features of my invention;

Fig. 4 is a view taken along the line 4-4 of Fig. 3; and

Figs. 5 to 8, inclusive, show diagrammatically difierent positions of the compressor piston during operation thereof.

Referring to the drawings, and particularly Fig; l, the numeral 2|] designates in general a refrigerating system diagrammatically representing as including a condensing element 22 and refrigerant evaporators 24 and 26, which may be of the flooded float control type, although other types may be used. Evaporators 24 and 26 are adapted to refrigerate compartments 28 and 30, respectively, at different temperatures by means of a multiple suction compressor 3| (see Fig. 4) forming a part of the condensing element 22, which is hereinafter described in detail.

Liquid refrigerant is supplied to the evaporators 24 and 26 by means of a common liquid supply conduit 32 and evaporated refrigerant is withdrawn from the evaporators 24 and 26 through vapor conduits 34 and 36 at different suction pressures by means of the multiple suction compressor 3|, the conduit 34 being connected to a relatively high suction pressure port 42, and the within the chamber".

conduit 36 being connected to a lower suction pressure port 44 of compressor 3|. The compressor 3| compresses the refrigerant vapor and delivers it to a condenser 43 wherein it is liquefied and from which it is delivered to a liquid refrigerant receiver 45 to which the conduit 32 is connected. A

Under the above conditions, the temperature of evaporator 24 and the temperature in compartment 28 will be maintained lower than the temperature of evaporator 26 and the temperature in the compartment 30, although the evaporators 24 and 26 may be of the same capacity and the insulation surrounding the compartments be the same. This is due to the difference in suction pressures of the compressor 3| and the difference in removal of heat from evaporators 24 and 26 caused thereby. Consequently, it will be noted that I have arranged for maintaining a temperature. diiferential between a number of different refrigerant evaporators by means of a multiple suction compressor. v

As shown in Figs. 3 and 4, the compressor 3| is enclosed in a, hermetically sealed casing 56. The casing 50 is formed preferably of three parts, namely; a central casting member 54 and sheet metal enclosures 55 and 56 joined to the casting 54 at opposite ends thereof. An electric motor 60 is also enclosed within the casing 56. The motor includes stator 62 and rotor 64. Rotor 64 is carried by shaft 66, which shaft is journaled in a bearing 68 preferably formed integrally with the casting member 54. On the opposite end of the shaft 66 I have mounted the compressor 3|. This compressor is of the so-called rotary type and includes a cylinder block ,10 clamped between a vertically extending wall member 12 formed preferably integral with the casting member 54, and an outer plate member 14 by means of screws 15. Within the cylinder block 10 there is provided a piston chamber 11 in which there is disposed a piston member 18 arranged for movement about the cylindrical -wall of the chamber 11 by means of an eccentric member 86 carried by shaft 64 and locked thereto by means of key 8|. Theshaft 66 extends through the chamber 11 and the shaft end I9 is jourrialed in a bearing 82 carried by plate 14. The piston is provided with a blade 83, which extends through an opening 86 in an oscillating member 84. The oscillating member 84 is arranged for movement within the walls of the cylinder block III, while the blade 83 is arranged for reciprocation within the opening 86 provided in the member 84. By this arrangement, ro-- tation of shaft 66 and the eccentric member will cause movement of the piston 18 about the wall of the chamber 11, while the blade 83 will oscillate with respect to the axis of the member 64. v

' As shown in Fig. 4, I have disposed the low suction pressure port 44 in close proximity to the left side, as viewed in the drawings, of the blade 83, and I have disposed the relatively higher suction pressure port 42 ,at an angle considerable less than there'from. However, itis to be understood that the port 42 may be disposed at any place about the periphery of the chamber 11, depending upon the capacity of the compressor desired. A discharge port 92 is provided for the discharged gas compressed A suitable discharge valve 94 is provided in the discharge port 92. As shown, the high compressed gas is discharged and 42.

within the sealed casing 50 whence it passes through the outlet 96 provided in casing 56,

' through conduit 91 to the condenser 44.

As shown in Fig. 4, the piston member "is compressing gas on the right hand side thereof andgas is being drawn into the .chamber 11 on the left hand side thereof. In order to more clearly describe the operation of the compressor, I have shown in Figs. 5 to 8, inclusive, various positions assumed by the piston within the chamber 11 during operation thereof. In Fig. 5, the piston 18 is just starting on its suction stroke whereby refrigerant vapor is being drawn into the chamber 11 through the port 44 and the piston 18 is compressing gas in the chamber 11 between its right hand side and the wall of the chamber 11. Fig. 6 shows the piston after it has moved past the high suction pressure port 42 whereby refrigerant vapor is being drawn into the chamber 11 through the port 42, and in so doing this refrigerant vapor, which is at a higher pressure than the vapor which enters the chamber 11 through port 44, will tend to compress the vapor previously drawn into the chamber 11 through port 44 and prevents the further flow of vapor into chamber 11 through port 44 at this time. Thus, the high pressure vapor compresses the low pressure vapor within the chamber 11 so that upon compression of the precompressed gas, less work will be required of the compressor than if it were required to compress gas at a pressure which is equal to that which enters into the chamber 1 1 through port 44. As will be noted in the drawings, the suction stroke of the piston 18 from port 42 to the discharge port is greater than the distance between the ports 44 Thus, by the present arrangement of the high and low pressure suction ports, more refrigerant will be drawn into the chamber [1 through port 42 than through port 44. In order to prevent back flow of gas into the conduits 34 and 36, I have provided'these conduits with check valves I00 and I III, respectively. Fig. 7

of the flooded type in which the pressure of the refrigerant bears a direct relation to the temperature of the evaporators. Consequently, the operation of the system will be controlled in response to changes in temperature within the evaporator 24. In a system of this type, it is immaterial, however, whether the operation of the compressor is controlled by changes in pressure in the vapor conduit 34 or in the vapor conduit 36, as the compressorwithdraws vapor from both evaporators during its operation. In order to control the operation of the motor-compressor unit in response to changes in pressure within the conduit 34, I have provided an automatic switch 91 which is adapted to connect and disconnect the motor to and from the power mains 98 at predetermined pressures.

From the foregoing, it will be apparent that I have provided a refrigerating system of a type including a plurality of refrigerant evaporators and that I have provided for maintaining a temperature differential between the evaporators whereby a number of different compartments are cooled at different temperatures by means of a multiple suction compressor, and that I have further taken advantage of such an arrangement by precompressing some of the vapor before it is compressed by the compressor. This arrangement is particularly advantageous in that the compressor is required to do less work and the capacity thereof is greater than if it were required to compress gas from a pressure equivalent to that existing in a lower temperature evaporator to a pressure at which the refrigerant would condense. Thus, it will be noted that I have provided a simplified form of maintaining a temperature differential within a number of refrigerant evaporators and that I have accomplished this in a simplified and inexpensive manner.

Referring to Fig. 2 of the drawings, there is shown a modified form of refrigerating system which is of the type suitable for installation in any of the so-called household refrigerators. The system includes a condensing element I20 and refrigerant evaporators I22 and I24. Evaporator I22 is adapted to cool compartment I26, which compartment may be a food storage compartment of a household refrigerator.

Preferably this compartment is to be main tained at temperatures suitable for refrigerating food articles stored therein. Evaporator I24 is adapted to cool an insulated compartment I30 at temperatures lower than that to which evaporator I22 cools compartment I26. Evaporator I24 is used primarily for freezing ice cubes, and for this purpose I have provided an ice tray I32, which is adapted to rest on a lower portion I34 of evaporator I24. The compartment I30 may be called a freezing compartment and may be located in the same household refrigerator cabinet as the compartment I26 is located. Liquid refrigerant is supplied to the evaporators I22 and I24 by means of liquid supply conduits I40 and I42 which are connected to a liquid refrigerant header I 44. The evaporator I24 may be of the flooded float control type wherein a constant level of liquid refrigerant is maintained by means of a float valve mechanism (not shown). Liquid refrigerant is supplied to the header I44 through a conduit I 50 under the control of a high side float I 52. Evaporated refrigerant is withdrawn from the evaporator I22 through the top of the header I44 by means of the conduit 34, which is connected to the high suction pressure port 42 of compressor 3|. Evaporated refrigerant is withdrawn from the evaporator I24 by means of the conduit 36 which is connected to the relatively low suction pressure port 44 of the compressor 3|. Any

suitable means may be provided for controlling the operation of the motor-compressor unit and, as shown herein, I have provided a pressure responsive switch I56 responsive to changes in pressure within the conduit 34 for actuating switch I56 to cut the motor in and out of circuit with the power mains I45 inresponse tochanges in pressures in conduit 34. By the present arrangement the evaporator I22 will be subjected to considerable more heat than the evaporator I24, and, consequently, it will be necessary to remove this heat in order to maintain predetermined temperatures within the compartment I26. This heat is due to the factthat in household redoor opening. For this reason I have arranged for withdrawing the evaporated refrigerant from the evaporator I22 by means of the high suction pressure portion of the compressor and have arranged for withdrawing the evaporator refrigerant from the low temperature evaporator I24 by utilizingthe lower suction pressure part of the compressor. The evaporator I24 may be of a larger heat capacity than the evaporator I22 and as shown the evaporator I24 is utilized primarily for freezing ice cubes. Thus, the possibility of heat transfer into this compartment is considerable less than the heat transfer into compartment I26. For this reason, it is desirable to connect the evaporator I22 to the high suction pressure port of the compressor. In the system shown in Fig. 2, the high temperature evaporator is shown connected to the high suction pressure port of the compressor 3i, while .in Fig. 1 the low temperature evaporator is shown connected to the high suction pressure port of the compressor. However, this arrangement may be changed to suit the conditions of the refrigerating system. In the system shown in Fig. 1, the evaporators are of the same heat capacity, while in Fig. 2, the evaporators shown are of different heat capacities and are arranged for cooling different sized compartments in which the heat removal problem is considerably different from that of the compartments shown in Fig. 1. Thus, it will be apparent that the compressing unit is readily adaptable for a number of different purposes where it is desired to maintain a number of different temperatures by a number of different evaporators.

Although only a preferred form of the invention has been illustrated, and that form described in detail, it will be apparent to those skilled in the art that various modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

What I claim as my invention is:

1. A refrigerating system comprising, in combination, a number of different refrigerant evaporators, a refrigerant condenser, a refrigerant compressor having a high suction pressure inlet and a lower suction pressure inlet for refrigerant to be compressed, and having an outlet, a conduit interconnecting the outlet of one of said evaporators with the high suction pressure inlet, a conduit interconnecting the outlet of the other evaporator with said lower suction pressure inlet, a conduit interconnecting said compressor outlet with said condenser, means for delivering condensed refrigerant to said evaporators, and means responsive to changes in conditions in said high pressure evaporator for controlling the operation of said compressor.

2. A refrigerating system comprising, in combination, a number of different refrigerant evaporators', means for maintaining a predetermined temperature differential between said evaporators during the entire operation of said means and means solely responsive to changes in conditions in one of said evaporators for controlling the operation of said means.

operation of said means and nieans solely re-,

sponsive to changes in conditions in one of said freezing substances, a multiple suction compressor associated with said portions of said heat absorbing means, and a thermostat associated with said portion of the heat absorbing means which cools the circulating air for controlling the operation of the multiple suction pressure 5 compressor.

LAWRENCE A. PHILIPP.

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