US2147508A - Refrigerating apparatus - Google Patents

Description

Feb. 14, 1939. G. M. mom 2,147,508

REFRIGERATING .APPARATUS limi INVENTOR. Gemea- M. 77u01. I7 'Y ffl-s ATTORNEY'S.

Feb. 14, 1939. G. M. TROUP REFRIGERATNG APPARATUS vFiled May 20, 1935 2 Sheets-Sheet 2 INVENTOR. 6fm? 6A' f. 7k,-

HIS ATTORNEYS.

Patented Feb. 14, 1939 PATENT oFFlcE REFRIGERATIN G APPARATUS George M. Troup, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a cox'-r poration ot Delaware Application May 20, 1935, Serial No. 22,332

This invention relates to refrigerating systems and particularly to the so-called high side iioat type systems.

In refrigerating systems of the so-called high side float type wherein the float valve mechanism is on the high pressure side of the system, as distinguished from the so-called low side float type wherein the oat valve mechanism is ordinarily located in the evaporator of the system and responsive to the level of liquid refrigerant in the evaporator or in the low pressure side of the system, the maintenance of a predetermined level of liquid refrigerant in the evaporator has been obtained by a predetermined charge of the volatile refrigerant contained in the system. If this charge of refrigerant in a system of the high side float type is varied, either by incorrectly charging a quantity of refrigerant into the system or by slight leaks, etc., the liquid refrigerant level in the evaporator will vary thus causing erratic operation of the refrigerant liquefying and circulating unit of the system to maintain the evaporator at its proper temperature. Therefore the charging of a correct and predetermined amount of volatile refrigerant into a system of the high side oat type has been a tedious and diilicult task requiring expensive and intricate mechanisms.

An object of my invention is to provide a refrigerating system of the so-called high side float type with a means whereby a predetermined liquid refrigerant level may be maintained in the evaporator irrespective of the amount of refrigerant contained in the system.

Another object of. my invention is to provide an improved refrigerating system of the so-called high side float type which eliminates the use of complicated and expensive charging mechanisms for placing refrigerant into the system. 40 4In carrying out the foregoing objects it is a still further object of my invention to provide a so-called high side float type refrigerating system with a means for controlling the flow of liquid refrigerant throughout the system which means is adjustable from the exterior of the' closed system for varying the liquid refrigerant level in the evaporator or for maintaining a predetermined level therein to thereby obtain continued and uniform operation of the refrigerant liquefying and circulating unit of the system.

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.

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In the drawings:

Fig. 1 is a diagrammatic showing of a refrigerating system having one form of my invention incorporated therein;

Fig. 2 is an enlarged vertical cross-sectional 5 view of a device employed in the system disclosed in Fig. 1 to provide an improved system according to my invention; and

Fig. 3 is a diagrammatic showing of a refrigerating system having another form of my inven- 10 tion incorporated therein.

Referring to the drawings, for the purpose of illustrating my invention, I have shown in Fig. 1 thereof a refrigerating apparatus including arefrigerator cabinet II) of the conventional house- -15 hold type comprising insulated walls Il forming a food storage compartment I2 having an access opening closed by a door I3. An evaporator I 4, preferably of the well-known sheet metal variety adapted to receive ice trays I5, is mounted in any 20 suitable manner within the compartment I2 of cabinet I0. 'I'he evaporator I4 is provided with a plurality of refrigerant expansion passages through which the refrigerant lcirculates during evaporation thereof to absorb heat from com- 25 partment I2 and the substance contained in trays I5. 'I'he evaporator I4 forms a part of a closed volatile refrigerant circulating system and is provided with liquid refrigerant inlet and gaseous refrigerant outlet connecting pipes I'I and I8 re- 30 spectively. The refrigerant liquefying and circulating unit of the system includes a motor 20 operatively connected to a compressor 2| through belt and pulley connections 22. Operations of motor 20 are controlled by a switch 23, of any 35 conventional design, including bellows or diaphragm 24 utilized for actuating the switch. Bellows 24 is connected by a pipe 25 to a thermof stat bulb 26 and this closed thermostatic system is charged with a suitable iiuid which, upon being expanded or contracted by changes in temperature of the evaporator I4, causes movement of the bellows for actuating switch 23to start or stop motor 20. The gaseous refrigerant'pipe I8 leading from evaporator I4 is connected to com- 45 pressor 2| and when the compressor operates it draws vaporized refrigerant from the evaporator. This vaporized refrigerant is compressedby compressor 2| .and circulated through pipe 28 under pressure to a condenser 29 wherein the com- 50 pressed refrigerant is cooled and liquefied, in any suitable and well-known manner, and caused to flow into a. reservoir or receiver 3|. Normally this liquid refrigerant flows directly from condenser 29, or from the bottom of receiver 3| 55 through a conduit 32, to casing 33 which houses a float valve mechanism including a float 35 operatively connected to a needle valve 36 and which mechanism is utilized to divide the closed refrigerant circuit into a high pressure side or portion and a low pressure side or portion. In this type of refrigerating system the float valve mechanism is in the high pressure side or portion as distinguished from other systems wherein the float valve mechanism is in the low pressure side or portion of the system.

Ordinarily the charge of refrigerant in a system of the type herein disclosed is predetermined and is such that when liquid refrigerant flows from receiver 3| into casing 33 it is an indication that more liquid is required in evaporator I4. 'lherefore flow of liquid refrigerant from the condenser 23 or from receiver 3| into casing 33 causes the level of refrigerant in the casing 33 to rise and the float 35 therein is raised accordingly. Rising of float 35 actuates valve 36 into open position and liquid refrigerant contained in casing 33 then fiows through the liquid refrigerant pipe I1, which may be of a capillary tube or any other suitable restricted flow type element, into the refrigerant expansion passages of the cooling element or evaporator |4. Float 35 upon reaching a low level, such as is shown in the drawings, for example, closes valve 36 against its seat and stops the flow of liquid refrigerant through pipe Il to evaporator I4. Operation of the compressor, may however, continue to cause continued or subsequent flow of liquid refrigerant into the float chamber or casing 33 and thence to evaporator I4 until the temperature of the evaporator has decreased to a point to cause the thermostatic system, comprising the uid contained in bellows 24, pipe 25 and bulb 26, to actuate the switch 23 into circuit-breaking position.

The level of liquid refrigerant maintained in the evaporator I4 of a system of the type disclosed has therefore been determined by the amount or rate of flow of liquefied refrigerant from the condenser 29 or receiver 3|. It is apparent that such a system necessitates the charging into the system of an exact or predetermined amount of volatile refrigerating medium or fluid to permit uniform operation of the refrigerant liquefying and circulating unit and to prevent erratic operation thereof. It is also apparent that any deviation .from the predetermined charge of refrigerant into the system will cause erratic operation of the refrigerant liquefying and' circulating unit. For example, a charge of too great an amount of refrigerant into the system will result in an increased level of liquid refrigerant in the evaporator thereof and this abnormally increased level will permit the compressor to suck or withdraw some liquid refrigerant from the evaporator thus causing frost to accumulate on the refrigerant suction line or pipe I8. Again if too little a charge of refrigerant is placed in the system, or in case of a temporary leak from the system of a part of a proper charge, the compressor will be operated over abnormal lengths of time in'an endeavor to lower the temperature of the evaporator to its proper low limit Due to the importance of placing an exact predetermined amount of refrigerant in a refrigerating system of the type herein disclosed and described it is obvious that complicatedand expensive charging devices or mechanisms are necessary to insure that such refrigerant charge is not varied beyond close limits.

Since my invention is directedto the elimination of complicated expensive charging devices and to the provision in a system of the type disclosed of a means whereby a predetermined liquid refrigerant level, or a plurality of different liquid refrigerant levels, may be maintained in the evaporator thereof, irrespective of the amount of refrigerant in the system, I will now describe the construction and function of a device I have placed in the system to provide a novel and improved refrigerating system. The inlet opening to the conduit or pipe 32 which conveys liquid refrigerant from the receiver 3| to the float valve chamber 33 is, in the present disclosure, made adjustable. This pipe 32 extends through a tubular casing 38 (see Fig. 2) which casing has its one end secured, such as by welding same, to the lowermost portion of receiver 3|. The inlet end 39 of tube 32.normally extends to a point above the bottom wall of receiver 3|. The portion of pipe or tube 32 adjacent the lower end of casing 38 has two shoulder or collar members 4| and 42 surrounding and secured thereto in spaced apart relation. A nut 43, threaded as at 44, surrounds the tube 32 between the collars 4| and 42 and the threads 44 are adapted to engage threads 46 provided on the interior of casing 38. Intermediate collar 4I and the inlet end 39 of tube 32 there is provided a bellows 41 which surrounds the tube or pipe 32 and has its lower inturned end portion sealed, such as by being welded as at 43, to the outer Wall surface of tube 32 and its upper outwardly turned end portion sealed, such as by being welded as at 49, to a shoulder-5| provided in the hollow tubular casing 38. It will be noted by observance of the showing of the parts just described in Fig. 2, that the nut 43 loosely engages tube or pipe 32 between collars 4| and 42 so as to be freely rotatable thereon and that the nut 43 is provided with a. small vent opening 52 which extends entirely through the nut and permits movement thereof into and outwardly of casing 38.

The operation of charging refrigerant into my improved system need not be a delicate or troublesome task carried out only by complicated and expensive mechanisms because of the provision for adjusting the inlet end 39 of pipe or tube 32, which conveys liquid refrigerant from the receiver 3| to the float valve chamber 33. For example, should too much liquid refrigerant be placed in my system whereby the flow of refrigerant from the bottom of receiver 3| to the float valve casing 33 is too great, and creates an abnormal high level of liquid refrigerant in the evaporator to cause the compressor 2| to withdraw liquid refrigerant from the evaporator, the nut 43 may be threaded inwardly of the tubular casing 38 so as to raise the inlet 39 of tube 32. By elevating the inlet end 39 of tube 32 a portion of the excessive charge of liquid refrigerant in the system is caused to be trapped in the lower part of receiver 3|. The excessive amount of liquid refrigerant put into this system is prevented from being circulated throughout the system or to the evaporator thereof to thereby render the additional refrigerant ineffective to cause the undesirabilities resulting therefrom as hereinbefore pointed out. Should the charge of liquid re frigerant into the system be slightly less than is ordinarily required my improved system can be rendered operative to efficiently produce refrigeration without erratic or long operating periods of the compressor. In the case of less than the normal amount of refrigerant in the system the nut 43 is threaded outwardly of the tubular casing 38 so as to move the inlet end 39 of tube 32 down to a point near the lowermost part of the receiver 3|. Movement of the inlet end 39 of tube 32 downwardly of receiver 3| decreases the amount of liquid refrigerant to be trapped in receiver 3| and thereby permits more refrigerant to be circulated through the system to provide the proper liquid refrigerant level in the evaporator I4 and to prevent erratic operations of the refrigerant liquefying and circulating unit.

I Referring now to Fig. 3 of the drawings wherein I have disclosed another form of my improved refrigerating system it will be noted that the receiver shown in the system disclosed in Fig. 1 has been omitted and that another form of means, for obtaining different refrigerant levels in the evaporator or for controlling the amount of liquid refrigerant to' be circulated throughout the enclosed circuit irrespective ofthe amount of refrigerant in the system-has been substituted for that shown in the system disclosed in Fig. 1. It is to be understood that the reference characters found in Fig. 3 of the drawings which are similar to the reference characters disclosed in Fig. 1 designate like parts or elements in the two systems. The compressed liquefied refrigerant iows directly from the lowermost portion of condenser 29, in the system shown in Fig. 3 of the drawings into the oat valve casing or chamber 33. Liquid refrigerant upon being permitted to flow into casing 33 causes elevation of float 35 and actuation of valve 36 into open position and this refrigerant is conveyed through the pipe 6I to the bottom of a reservoir trap 62. 'Ihe liquid refrigerant must ll this reservoir trap 62 before flowing from the top thereof through pipe 63 in its course of iiow to the evaporator I4. I place a bellows within trap 62 and this bellows has 4 its upper end sealed to the top wall of trap 62 and its lower end sealed to a metal disc or plate 66. A-

threaded opening 61 is provided in the top wall of trap 62 for the reception of a threaded shaft 63. The upper end of shaft 68 has a knob or handle 63 formed thereon for facilitating turning of the shaft. Pressure of refrigerant within the system and particularly within the trap 62 tends to collapse the bellows 65 therefore the disc or plate 66 is maintained in abutting relation at all times with the lower end of the threaded shaft 68. In this form and arrangement of my invention bellows 65 is adapted to be expanded or contracted to vary the capacity of the reservoir trap 62 to adjust or regulate the amount of refrigerant to be circulated throughout the system or to evaporator I4. Should there be an excessive amount of refrigerant placed in the system disclosed in Fig. 3 of the drawings the iloat valve mechanism will permit substantially all of the excessive refrigerant to ilow from the float casing. This excessive refrigerant is, how- .to the evaporator and throughout the system.

From the foregoing it will be apparent that I have provided improved refrigerating systems of the so-called closed high side oat type and that I have provided an improved means in such systems for varying or regulating the amount of refrigerant to be circulated through the system so as to insure the maintenance of a proper predetermined liquid refrigerant level in the evaporator irrespective of the total amount of refrigerant placed in the system. My invention greatly reduces the cost of charging refrigerating systems of this type and in addition renders service calls less expensive due to the wide adjustment of the system for various refrigerating requirements.

While the forms of embodiment of the invention as hereindisclosed, constitute preferred forms, it is to be understood that other forms might be adopted, all coming within the scope of the claim which follows.

What is claimed-is as follows:

A refrigerating apparatus comprising, a closed circuit having a refrigerating medium therein, means for circulating the refrigerating medium through said closed circuit, means for dividing said closed circuit into a high pressure portion and a low pressure portion land for admitting the refrigerating medium from said high to said low pressure portion of the circuit, a stationarily mounted refrigerating medium storage receptacle interposed in the high pressure portion of the circuit between' said first and said second named means, means extending through an opening in a wall of said storage receptacle and forming therewith a trap for varying the capacity of the receptacle to thereby increase or 'decrease the amount of refrigerating medium to be circulated through the circuit, saidlast named means being adjustable from the exterior of said closed circuit to cause vertical movement thereof relative to said stationarily mounted receptacle without moving the receptacle. and an element sealed to said last named means and to the wall of the opening in said storage receptacle through which said last named means extends to provide a fluid tight joint therebetween. said element being nexible to permit said vertical movement of said last named means relative to said receptacle.

GEORGE M. TROU?.

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