US2095011A - Refrigerating apparatus - Google Patents

Description

Oct. 5, 1937. i L. A. PHILIPP 2,095,011

REFRIGERATING' APPARATUS I Filed MarchZZ, 1933 ATTORNEY.

Patented Oct. 5 1937 {PATENT o F -cE 2,095,011 BEFRIGERATING APPARATUS Lawrence A. Phiiipp, Detroit, Mich, assignor, by

mesne assignments, to Nash-'Keivinator Corporation, Detroit, Mich, a corporation of Maryland Application March 22, 1933, Serial No. 662,057

8 Claims. (01. 62-115) This invention relates to refrigerating apparatus, and more particularly to refrigerating apparatus of the multiple temperature type.

One of the objects of my invention is to prov vide an improved refrigerating system for freezing substances and for cooling circulating air in a refrigerator cabinet.

Another object of myinvention is to provide a simplified arrangement for attaining a tem- 10 perature differential between a number of different refrigerant evaporators in a refrigerating system.

Another object of my invention is to provide an improved refrigerating system and controls therefor for maintaining different temperatures within predetermined ranges in different parts of a refrigerator cabinet.

Another object of my invention is to-provide within a refrigerator cabinet an improved ar- 2 rangement of and control for refrigerant evaporating means, which is arranged and operated without the collection of frost thereon or a slight film of frost is allowed to collect thereon during the onphase of the refrigerating. cycle and is 25 melted off during the off-phase of the refrigerating cycle, while at the same time provisions are made for freezing substances, such as ice cubes and the like, and for cooling circulating air in the food storage compartment whereby. continuous refrigeration at substantially constant predetermined temperatures is assured and the necessity of periodic inoperative conditions of the system for defrosting is avoided.

- Another object of my invention is the simplicity of parts and their arrangement within the refrigerator cabinet whereby the aforesaid/objects ,may be economically and easily carried out.

Other objects and advantages will be apparent from the following description, reference being I 40 had to the accompanying drawing.

In the drawing:

Fig. 1 is a vertical view, partly in cross section and partly in elevation, of a refrigerating apparatus embodying features of my invention;

45 "Fig. 2 is a fragmentary view of the apparatus shown in Fig. 1, taken in the direction of arrows 2-2 in Fig.1;

'Fig. 3 is a vertical view in cross section of a control valve embodying features of'my inven- 3 tion; and

Fig. 4 is a view taken along the line 4-4 of Fig.3. Referring to-the drawing, the numeral: 29 designates. in general, a cabinet having a come Miami; 22 .for the storage of foods to be refrigerated, a freezing compartment 23,. and a machine compartment 24. The cabinet is constructed of insulating walls, including side walls 26, rear wall 21, front wall 28', bottom wall 29 and top wall 30. The cabinet also includes a fixed, vertical insulating wall 32 which extends from the rear wall 21 to the front wall 28 and from the top wall 30 to the bottom wall 29, separating the food compartment from the freezing compartment. An inner metallic lining. member 35 forms the inner walls of the food compartment and is, preferably, provided with a coating of vitreous enamel, such as porcelain, to provide a neat appearing compartment and one which may be easily cleaned. A similar inner metallic lining member 31 forms the inner walls of the compartment 23. The liner 31 may be coated the sameas'liner 35. The front wall 28 is provided with an opening 38 through which access may be had to the food compartment 22. *The opening 38 is closed by door 40. A second opening may be provided in the front wall 28 in advance ofthe freezing compartment-23 for gaining access to the compartment 23. Any suitable door (not shown) may be used for closing the latter open-+ ing in wall 28.

Within the freezing compartment 23 is disposed a refrigerant evaporator 45 which is suspended from wall by brackets 41. The evaporator 45 comprises, in general, a header 49 which has 30 a space within its interior for both liquid and gaseous refrigerants. v Dependingv upon the header 49 are a plurality of conduits 50. -To the conduits 50 are attached a plurality of vertically spaced refrigerant containing shelves'il. The shelves 5i are provided for supporting ice makingreceptacles (not shown). Liquid refrigerant is delivered to the shelves 5| through conduits 50, which are in open communication on their 7 upper ends with the header 49 and also in open communication with the interior of each of the shelves 5|. Preferably, the shelves are constructed of sheet metal plates suitably secured together bywelding but spaced apart between the sheets of metal. By operating the evaporator 45 at sufliciently low enough temperatures and by supporting the ice making receptacles on the upper surfaces of the refrigerant containing plates, the water in the receptacles will be rapidly frozen. If desired, desserts and the like may be placed in the receptacles stored on the'shelves ll. Also. if desired, the frozen deserts and. the like may be removed when frozen from the shelves andplaced on thetopof the wall29ineompartmeat 23 immediately below'the evaporator 5 where the substances will be retained in a frozen condition, I

Within the food compartment 22 there is disposed a refrigerant evaporator 50. Evaporator 55 is of the plate type and is secured to the wall :2.

As willbe noted in the. drawing, the evaporator 55 extends over the major portion of wall 02 within compartment '22. By providing an evaporator of this size and by solocating it in compartment 22, it is possible to substitute for the insulated wall 32 a thin metallic wall since the evaporator is arranged to prevent the transfer of heat from the compartment 22 into the com-' partment 23. Preferably, the evaporator 55 is constructed of sheet metal plates which are secured together about their peripheries thereof by seamwelding and welded at various points intermediate their edges but spaced apart between the welded points to provide a space for refrigerant. In order to increase the heat transfer characteristlcs of evaporator 55, I haveprovidedaplurality'of spaced parallel fins 51 on one 'side of the evaporator".

- A refrigerant condensing element 50 is disposed in the machine compartment 24. This elementmay be supported in compartment 24 by any suitable means (not shown). The elementinciudes a compressor 52, motor. 53 for operating the compressor, condenser 65 and high side float mechanism 51. The compressor 52 withdraws evaporated refrigerant from the evaporators 45 and 55 through a vapor-conduit 09, compresses the evaporated'refrigerant and delivers itto the condenser wherein it is liquefied and from which.

it is delivered to the high side float mechanism 61. Liquid refrigerant is delivered to the evaporators through liquid supply conduit 10 under the control of float mechanism 51. l

.. Liquid refrigerant is first delivered to evaporator 55 through a conduit 10, and from the evaporator 55 liquid and gaseous. refrigerant is delivered to the evaporator 45 through conduit 12.

Evaporated refrigerant is withdrawn from the evaporator 45 through the vapor conduit 50.

Preferably, the condensing element is i'ntermit tently operated. In order-to control the operaorator 55. switches of this'type are well. known in the art and'further illustration thereof in the drawing is deemed unnecessary. Thus, it will be noted that the operation of motor 55"is controlled in response to changes in temperatures in either or both of the evaporators. In view of the fact that the evaporators 45 and 55 are of the T so-called flooded type, the temperatures therein bear direct relation to the pressure existing therein. I r

'. m order to maintain e predetermined tempereture differential between the evaporators 45 and. 55 during operation of :the condensing element, I have provided a pressure responsive valve. I05

-which is interposed in the conduit 12 for controlling the flow of liquid and gaseous refrigerant from,'the evaporator 55 to the evaporator 45.

The pressure responsive valve I05 is adapted to maintain a. predetermined pressure di'iferential between the evaporators l5 and 45 during operation of the condensing element'to thus maintain a temperature differential between said evaporators. As shown in Fig. 3,,thepressure responsive valve includes a valve proper I01 and valve seat m located within a casing I00. The casing I00 is provided with an inlet l i0 to "which that portion of conduit 12 which extends between the valve I05 and the outlet end of evaporator 55 is connected. The valve I05 is also provided with an outlet M2 to which theevaporator 45 is connected by another portion of the'conduit 12. The valve proper I0! is secured to weight 5 which is adapted to move upwardly and downwardly within a chamber H6, depending upon the pre'ssure of the refrigerant exerted on valve proper 5 I01. Preferably, the chamber 1 l0 is cylindrical in shape and also, preferably. the weight H5 is provided with a'plurality of arcuate portions Ill away flat portions HQ-between the arcuate portions 0 to provide spaces between the walls of the chamber and the weight so as to prevent binding of theweight in the chamber, and also to prevent a. dash pot action therein. When the pressure of the refrigerant in the evaporator 55 reaches a predetermined point, for example, equal to the pressure withinthe evaporator 45, and 'is of sufllcient force to lift weight I I5 and the valve proper, the liquid and gaseous refrigerant will which conform to the contour of the walls of. the v chamber. The weight is also provided with cut-,

move the valve I01 and weight 5 upwardly to 1 allow liquid and gaseous refrigerant to enter the chamber H5, whence it passes through outlet H2 inconduit 12 into-evaporator 45. When the pres- I sure recedes to a predetermined point, for ex-' ample, to a point less than it requires to open valve J01, the weight and valve proper move downwardly to cause the valve ,l01 to engageitself with seat 100 to prevent further passage ,of refrigerant into the evaporator 45. The

weighted valve is arrangedto .be intermittently,

operated so as t'o-m'aintain a predetermined pres- ,sure differential between the evaporators 45 and 55. As previously stated-herein, the pressure differential is controlled by the weight of the weight-1 1 ed valve proper I01. In other words, before refrigerant may pass from the evaporator '55 to the evaporator, the pressure within the evaporator 55 must be equal to the pressure in the evaporator 45, plus the amount equal to .move the weight tial is maintained during operation of the cone.

,densing element irrespective of the temperature ranges maintained in evaporators and H5 upwardly to remove the valve I01 from its seat I00. This predetermined pressure diiferen-;

i Preferably, the thermostatic switch is so that the evaporator will be operated at temperatures which are slightly above that which would be likely to cause the collection of frost or ice thereon due to the depositjof moisture, fromthe circulating air in the food compartment. If desired, the thermostat may be set to operate evaporator" at a temperature which would allow a slight 111m of frost to collect thereon during the on-phase of the refrigerating cycle and melted off during the off-phase oi the refrigerating cycle. set so as to cause operation of the condensing eleevaporator 45 so that said evaporator will be freezing therein. 7

In the refrigerating system herein described, I

Preferably, the thermostatic switch is is i 7 ment at predetermined pressure limits within the operated at temperatures :'which cause'rapid operation when thepressures within the evapo-.

prefer to use sulphur dioxide as a refrigerant. when sulphur dioxide is used as the refrigerant and when a predetermined setting of the switch 11 is made, I have found that the cyclic operation of the system is between an upper and lower pressure range limit in the evaporator, which limits may be fourteen pounds pressure when the motor cuts in and four pounds pressure of the.

refrigerant when the motor cuts out. By the use of the pressure responsive valve I05 and by determining the weight member I I5 thereof so that a seven pound pressure differential is maintained between the two evaporators during the operating of the condensing element, I have found that when the aforementioned pressure range limits exist in the evaporator 55 that the upper and lower pressure range limits existing in the evaporator 45 extend between an upper limit of four pounds pressure of the refrigerant and lower limit of six inches of. vacuum. With such pressure range limits existing in the evaporator 45, it

will be noted that the substances may be frozen rapidly.

Assuming that a large quantity of substances to be frozen should be applied to the ice freezing evaporator 45, the pressure of the refrigerant in said evaporator is increased by the heat of the substances. Inasmuch as the thermostatic switch 11 is responsive to changes in temperatures in the evaporator 55, it is necessary to provide some means .for immediately initiating operating of the condensing element 50 when a large quantity of substances to be frozen is applied to the evaporator 45 so that the heat absorbed by the refrigerant in the evaporator 45 may be immediately withdrawn to start .the process of freez- For this reason, the

ing the said substances. thermostatic switch 15 has been provided. Preferably, the switch 15 is arranged so that it cuts in the motor 63 when the pressure of the refrigerant inthe evaporator 45 reaches an upper limit of slightly above four pounds pressure and cuts out the motor 63 when the pressure of the refrigerant falls to six inches of vacuum. Thus, it will be noted that when the pressure in the evaporator 45 exceeds four pounds, the condensing element begins operation toreduce the pressure within the evaporator 45. Preferably, the switches 15 and 11 are connected in parallel 'so that the switch 'I'l will control the operation of the condensing element to maintain the desired tem-' taining the temperatures withinthe food storage compartment 22 within predetermined range limits, by simply controlling the operation of the condensing element by means of a thermostatic switch "I 'However, in order to control the operation of the condensing element so that ice may readily be frozen in thecompartment 23, I have,

provided the thermostatic switch I5 which immediately cuts the motor-compressor unit into rat'or 45 rise to slightly above four pounds irrespective of the pressures existing in evaporator v55. Thus, it will be noted that the pressure responsive switch I5 is included for promoting rapid ice freezing.

Although I have described my pressure differential valve H15 in connection with an interreadily be apparent from the foregoing that said valve may be used advantageously in a continuously operated system'where it would maintain a predetermined pressure differential between the evaporators 45 and 55 at all times.

From the foregoing, it will be noted that I have provided an improved and simple arrangement for maintaining a pressure differential between a number of different evaporators and for maintaining a* temperature differential therebetween. It will also be noted that the pressure differential is obtained automatically as the pressures in the evaporators are being reduced by the condensing element. In addition, it will be noted that said predetermined pressure differential is maintained irrespective of the setting mittently operated refrigerating system, it will,

immediately upon entrance of the liquid refrigerant into the supply conduit I0 after leaving the high side float mechanism 61, I have provided a pressure responsive valve, designated by the numeral I20. This valve is interposedin the conduit I0 adjacent the inlet of the evaporator 55. Thisvalve maintains the pressures in the supply conduit 10 sufficiently high enough so as to prevent refrigeration taking place in said conduit so that no refrigeration takes place before entering the evaporator 55. This prevents loss of refrigeration, increases the capacity of the apparatus and prevents the collection of moisture in the insulated portions of the food storage compartment through which the liquid supply- ,conduit 10 extends.

Preferably, the valve I20 is of the same construction as the valve I05, with the'weighted member H5 being of different size so as to maintain the pressure of refrigerant within the conduit 10 above that which would cause the collection of frost on the conduit I0. Thus, it will be noted that within the refrigerating system described herein, there are four portions thereof in which the pressures arev different. For instance, a relatively high pressure within the condenser 55, the pressure in the conduit 10 h which is somewhat belowthe pressure existing in the condenser and above the pressure existing in the evaporator 55, and a relatively low pressure which exists in the evaporator 45.

Although only a preferred formof the invention has been illustrated, and that form de-, scribed in detail, itwill-be apparent to' those skilled in the art thatvarious 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 a refrigerant condensing element, ,a number of different refrigerant evaporators connected in series,-

means connected in said system for maintaining a predetermined temperature differential between the different'evaporators during the operation of said condensing element, and means associated with each evaporator for controllingthe operation of said condensing element.

' 2. A refrigerating'system comprising a refrigerant condensing element, a low temperature refrigerant evaporator, a relatively high'temperature refrigerant evaporator, control means responsive to changes in conditions within said relatively high temperature-evaporator for initiat-- lnlr'operation of said condensing element when the temperatureof the refrigerant in said relatively high a temperature evaporator attains a certain high value; and for interrupting, the oper-z 5' ationof said element when said temperature'is ential, and the other temperature responsive means being operable onlyin the event of a pre-' reduced toacertain low value, auxiliary control.

means for controllingoperation of said condens- Y ing element only in the event the temperature in said lqw temperature evaporator exceeds the perature responsive means for controlling the 0 operation of said condensing element, one of said temperature responsive means being operable to normally control the operation of the condensing element to maintain said temperature dinerdetermined demand for refrigeration by one of said evaporators to'control the operation of said I condensing element to thereby insure'maintainso in: said substantially'constant temperature differential atalltimes.

v 4. A refrigerating system comprising a number of different refrigerant evaporating elements;

means for/ simultaneously reducing the pressures in said elements, temperature differential means 35 for maintaining a predetermined temperature differential between said elements, control means normally controlling the operation of the means for reducing said pressures, and auxiliary control means arranged to be effective to control 9 the operation of said pressure-'reducing-means in the event the temperatures in one of said evaporators isincreased toa certainamount.

. temperature evaporator, a relatively high temevaporator, pressure reducing means for controlling the flow of liquid and gaseous trolling the operation of saidcondensing element.

associated with s'aid'evaporators, means for main:

taining a predetermined pressure diiferential between said evaporators during operation of said pressure reducing means, and means directly associated with said low temperature evaporator ,5

for controlling the operation of said pressurereducing means. v i

6. A refrigerating system comprising a low temperature evaporator, a--relative1y high temperature evaporator, pressurereducing means as- 10 sociated with said evaporators, meansfor maintaining a predetermined pressure differential between saidevaporatorsduring operation of said pressure reducing means to maintains. predetermined temperature differential between said evaporators, and independent means directly associated with eachevaporator for controlling the operation of said pressure reducing means; 7. Arefrigerating system'comprising a refrigerant condensing element, a refrigerant evapolater, a second refrigerant evaporator connected in series with the first named evaporator, a pressure responsive valve connected in said system refrigerant from the first evaporator'to the sec- 'ond to maintain a predetermined temperature differential between said evaporators during the operation of said condensingelement, and means associated with each of said evaporators for con- 8: A refrigerating system comprising a refrigerant condensing element, a. refrigerant evaporator a second refrigerant evaporator connected in series with the first named evaporator, a pres I sureresponsive valve connected in said system for controlling the flow of liquid and gaseous refrigerant from the first evaporatorto the sec-'- ond' to maintain a predetermined temperature difierential between said evaporators during the operation of said condensing element, and thermostatic means directly associatedwith each of I said evaporators for controlling the operation -5. A refrigerating system comprising a low of said condensing element.

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