US 2332711 A
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Description (OCR text may contain errors)
Oct. 26, 1943- R. E. GOULD ET AL REFRIGERATING APPARATUS Filed 001;. 29, 1940 INVENTOR.
Patented Oct. 26, 1943 UNlTED STATES PATENT OFFICE BEFRIGERATING APPARATUS Richard E. Gould, Oakwood, and Charles F. Henney, Dayton, Ohio, assignors to General Motors Corporation, Dayton, Ohio, a corporationof Delaware Application October 29, 1940, Serial No. 363,317
= means for cooling and lubricating the compressor when no refrigeration is supplied to the evaporator.
Another object of this invention i to provide improved means for by-passing the main evaporator when no refrigeration is required.
Still another'object of this invention is to provide means for improving the efliciency of the refrigerating apparatus.
Further objects and advantages of. the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of th 'present invention is clearly shown.
In the drawing: v
The drawing diagrammatically shows our invention' as applied to a refrigerating system.
As disclosed in the drawing, the reference numeral l designates an air duct or a cabinet through which air to be conditioned is circulated. Reference numeral '2 designates an evaporator mounted in the pathof the air flowing. through the duct l. The air is circulated by means of a fan unit 3, which may be energized from any suitable source of electrical energy (not shown). The reference numeral 4 designates a conventional rotary compressor which discharges compressed refrigerant into the casing I! from whence the compressed refrigerant enters the line 5 which leads to the inner passage 6 of the heat interchanger 1. The refrigerant leaving the inner passage 6 is conveyed to the condenser 8.
through the line 9. The compressed refrigerant is condensed within the condenser 8 and. thereafter flows into a conventional receiver l0. Liquid refrigerant from the receiver to is circulated through the compressor cooling cham ber H.v
As shown in the drawing, the compressor casing comprises two sections l4 and H which are secured together by means of the cap screws IS. The end wall I3 of the compressorv 4 separates the interior of the easing into two separate chambars. The chamber ll surrounds th main com- 7 Claims. (Cl. 62-115) pressor shaft bearing [2 which may be formed integrally with the end wall 13 whereby the liquid refrigerant entering the chamber II serves to cool the mainbearing l2 and also serves to cool the compressor mechanism through the wall i3. A shaft seal i5, of conventional construction,
is provided at the point where the main shaft l6 passes through the casing I4. By virtue of the location of the shaft seal IS, the shaft seal is also kept cool by the refrigerant flowing through the chamber ll.
Inasmuch as a portion of the liquid refrigerant entering the chamber may be converted into vapor by the heat generated by the compressor mechanism and the shaft seal, the refrigerant leaving the chamber ll. is caused to discharge into the outer chamber '20 of-the heat interchanger l8. As will be pointed out hereinafter, the relatively cold refrigerant vapor leaving the evaporator 2 flows through the inner passage 22 of the heat interchanger l8 whereby the refrigerant vapor enteringthe' outer chamber 2!] is recondensed before leaving the chamber 20. The outer chamber is provided with two cutlets. A first outlet 23 leads to the main evaporator 2. A second outlet 24 leads to the outer chamber-25 of the heat interchanger 1. The flow of refrigerant from the chamber 20 to the evaporator 2 is controlled by a valve 26 which in turn 'is controlled by the thermostat 2'! which may be located either in the return air stream, as shown, or in the conditioned space. The valve 26 is adapted to be closed whenever the thermostat 21 indicates that the air flowing through the duct I .does' not require further cooling; In addition to the valve 26, a conventional thermostatic expansion valve 28 is provided for controlling the flow of liquid refrigerant to the evaporator .2 whenever cooling is required. The thermostatic expansion valve 28 is of conventional construction and includes the usual thermostatic element 29 placed adjacent the outlet of th evaporator for closing the valve 28 whenever the liquid refrigerant reaches the evaporator outlet.
The flow of refrigerant from the chamber 20 to the chamber 25 is controlled by a conventional expansion valve 30 which is set to open at a much lower pressure than the valve 28. The calibra tion of the valves .28 and 30 is such that sub-.- stantially all of the refrigerant flows through the evaporator 2| at all times when refrigeration is required and the only time that the valve 30 is open is when one or both of the valves 25 and 28 are closed. Upon opening of the valve 30, in respouse to a subnormal suction pressure, a prederefrigerant gas flowing through the inner chamher 6 of the heat interchanger I. The refrigerant vaporized in the chamber 25 is conveyed through the passage 3! to the inlet 32, of the chamber 22. Inasmuch as the refrigerant vapor flowing through the passage 3| will be relatively cool, it will serve to condense any refrigerant vapor which may enter the chamber 20.
One purpose of providing the interchanger i8 is to make sure that all of th refrigerant flowing either to the expansion valve 28, or to the expansion valve 30, is in liquid form so that the valves will operate properly. It has been found that valves of this type do not operate properly when refrigerant vapor is mixed with the refrigerant supplied to the valves.
By virtue of'the above described arrangement it is apparent that the system will cause a certain amount of refrigerant to be circulated by th compressor at all times even though hr. refrigerant is supplied to the evaporator 2. Inasmuch as it is frequently desirable to operate the compressor continuously, it is important that a certain minimum amount of refrigerant be circulated at all times so as to provide a constant supply of liquid refrigerant for cooling the compressor. The amount of refrigerant passed by be circulated by the compressor at all times so as to prevent damage to the compressor from overheating or the like. Inasmuch as modern compressors rely upon the circulation of refrigerant through the compressor for supplying lubrication to the compressor, it is also important, from the lubricating standpoint, to circulate a certain minimum amount of refrigerant through the compressor at all times when the compressor is in operation.
The reference numeral 40 designates any conventional compressor operating means such as an internal combustion engine or an electric motor. As shown in the drawing, the compressor operating means 40 also operates the condenser fan 4|.-
In order to simplify this disclosure, no control means have been shown for controlling the operation of the compressor operating means 40 as any conventional control means may be employed. By virtue ofthe improved arrangement of the refrigerating system, the compressor operating means may be operated continuously at a high -when refrigerant is not being supplied to the evaporator without injury to the compressor mechanism, the system is also well adapted for use with a. continuously running direct-connected electric motor.
'For purposes of illustration we have shown a system in which the refrigerant flowing through the by-pass valve 30 is evaporated by flowing through the heat interchanger 1, whereas it is within th purview of this invention to evaporate this refrigerant by other means. When an in-' ternal combustion engine is used for operating the valve 3|) is equal to the amount which must the compressor, the exhaustgas or the hot engine jacket water could be used in evaporating the refrigerant flowing through the by-pass. The by-passed refrigerant could also be used in doing useful cooling such as freezing ice, cooling air or the like. r
The valve 30 which is arranged in the bypass line may, if desired, be adjusted so as to allow a predetermined amount of refrigerant to leak through the by-pass line even though the suction pressure is above the-value at which the valve 30 moves to its fully open position. Leakage through the by-pass around the evaporator reduces the capacity of the evaporator whereby the valve 26 opens and closes less frequently. This causes smoother operation of the refrigerating system and, to a great extent, prevents frequent temperature fluctuations within the conditioned space. 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, all coming within the scope.
of the claims which follow.
What is claimed is as follows:
1. In combination, a compressor, a continuously running internal combustion engine for operating said compressor, a first evaporator, a second evaporator, a condenser, means for conveying liquid refrigerant from said condenser into thermal exchange with said compressor and a prime mover for driving said shaft, a condenser, an evaporator, a shaft seal cooling cavity, refrigerant flow connections between said evaporator, compressor, condenser and shaft seal cooling cavity, means for by-passing said evaporator, means for vaporizing refrigerant flowing through said by-pass, and means responsive to the suction pressure of said compressor for conv frigerant flow connections between said evaporator, compressor, .aeondenser and compressor cooling cavity, valve'means for preventing the flow of refrigerant to said evaporator, said refrigerant flow connections and said condenser being so constructed and arranged as to supply refrigerant tosaid compressor cooling cavity when said valve means prevents the flow of refrigerant to said evaporator and also when said valve means permits the flow of refrigerant to said evaporator.
4. In combination, a first evaporator, a second evaporator, refrigerant liquefying means including a condenser portion, means for conveying liquid refrigerant from said condenser portion into thermal exchange relationship with another portion of said refrigerant liquefying means and thereafter in thermal exchange relationship with refrigerant leaving either one of said evaporators so as to recondense the refrigerant vaporized while in thermal exchange relationship with said other portion, and means a for thereafter conveying said recondensed refrigerant to one 'refrigerant flowing to either said by-fiass or said evaporator in thermal exchange with said compressor, valve meanscontrolling the fiow of refrigerant to said evaporator, valve means controlling the flow of refrigerant through said bypass, and means for conveying refrigerant flowing through said by-pass in thermal exchange with refrigerant flowing from said compressor to said condenser.
6. In combination, a motor-compressor unit, a, first evaporator, a second evaporator, a condenser, means for conveying liquid refrigerant from said condenser into thermal exchange re- -lationship with a portion of said motorwompressor unit and thereafter into thermal exchange relationship with refrigerant vapor leaving one of said evaporators so as to recondense the refrigerant vaporized in thermal exchange with said compressor.
7. In combination, a compressor, means for operating said" compressor, a first evaporator, a second evaporator, a condenser, means for con-' veying liquid refrigerant from said condenser into thermal exchange with said compressor and I momma E. GOULD. onanws n. HENNEY.