US2461262A - Refrigeration - Google Patents

Description

Feb. '8, 1949. N. ERLAND AF KLEEN REFRIGERATION Filed June -2, 1945 INVENTOR MYJ' E2902? 0 [/8012 BY; ATTORNEY 8, 1949- N. ERLAND AF KLEEN 2,461,252

REFRIGERATION 7 Filed June 2, 1945 a Sheets-Sheet 2 IN V E NT R ATTORNEY Feb. 8, 1949.

N. ERLAND AF KLEEN REFRIGERATION 3 Sheets-Sheet 3 Filed June 2, 1945 Ill ////1 I 1/ 125 T A JM' 2 JVZZI' aid/112 Ba I MATTORNE? was rel. e, 1949 REFRIGERATION Nils Erland at Kleen, Stockholm, Sweden, as-

signor to Kleen Refrigerator, Inc., Hoboken, N. J a corporation of Delaware Application June 2, 1945 Serial No. 597,337 A This invention relates to new and useful improvements in the art of refrigeration and is a; continuation-in-part of my application, Serial No. 387,854 filed April 10, 1941, now abandoned.

It is well known in the art of refrigeration that in order to maintain a predetermined temperature in a refrigerator cabinet or the like by means of refrigerating apparatus of the absorption or adsorption type, a certain quantity of refrigerant has to be circulated. As the load on the refrigerating apparatus increases due to placing more comestibles in the cabinet, or to filling the ice trays with water to be frozen, or to rising room or ambient temperature, the rate of circulation of the refrigerant per unit of time must also be increased to maintain the desired temperature in the cabinet.

In view of such varying loads, it has generally been the practice to construct and design the refrigerating apparatus with a predetermined capacity such as to take care of the maximum loads to be encountered and to obtain the highest coeificient of performance of the refrigerating ap-' been comparatively low.

One of the objects of the present invention is to overcome the above noted disadvantages in refrigerating apparatus heretofore employed and to this end the invention consists in constructing and designing the refrigerating apparatus. to have its highest or best coefficient of performance when operating at normal loads and in providing means for overloading or increasing the capacity or output per unit of time of certain parts of the maximum refrigeration demands during the periods of maximum loads.

Another object of the invention is to provide means for varying the heating rate per unit of time of the heating means for that part of an absorption or adsorption refrigerating system in which the refrigerant is generated and also to provide means for varying correspondingly the cooling rate per unit of time of the cooling means for those arts of the refrigerating system in which the refrigerant is condensed or liquefied and is absorbed or adsorbed, respectively, and to control the operation of such rate-varying means in accordance with the demands for refrigeration so as to obtain the highest coefficient of performance of the system when operating under normal conditions.

, the refrigerating apparatus so as to takecare of 9 Claims. (cl. 62-5) A further object of the invention is to provide means for overloading or increasing the capacity per unit of time of certain parts of absorption or adsorption refrigerating apparatus and to control the operation of said overloading means in accordance with a condition affected by the evaporator and/or a condition affected by the ambienttemperature. 7

The above together with other objects and advantages of the invention will become more apparent as the description proceeds with reference to the accompanying drawings in which Fig. 1 is a diagrammatic view of intermittent absorption refrigerating apparatus embodying theinvention;

Fig. 2 is a similar view of a modification, and

Fig. 3 is a similar view of another embodiment of the invention. A

Referring to Fig. l .of the drawings, the refrigerator diagrammatically illustrated comprises a household refrigerator cabinet I0 having associated therewith an intermittent absorption refrigerating unit constructed and designed in accordance with the invention.

The refrigerating unit [comprises a closed system formed by a plurality of interconnected parts including a boiler-absorber or generator-absorber il containing strontium chloride or other suitable absorbent capable of absorbing ammonia or other refrigerant fluid employed in the system, a condenser l2 provided with heat dissipating fins and arranged in a flue space or duct F to be cooled by air, a receiving vessel i3 embedded in thethermal insulation of the cabinet i0, and an evaporator i4 located in the thermally insulated storage space l5 of the cabinet Ill;

The boiler-absorber II is heated by an electrical heating element or other suitable heating means It during what is known as the generating period of the unit to drive out or liberate the refrigerant from the absorbent. The refrigerant vapors driven out of the absorbent chamber of the boiler-absorber ii are liquefied in the condenser I2 and the refrigerant liquid is collected in the receiver i3 and evaporator it.

When all of the refrigerant that can be utilized for refrigeration purposes has been liberated from the absorbent and collected in the receiver and evaporator, heating of the boilerabsorber i I is interrupted and the latter is cooled during'what is known as the absorbing period of the unit to effect evaporation of the refrigerant liquid in the evaporator l4 and absorption of the vapor by the absorbent. As cooling means for the boiler-absorber l i, I haveshown a secondary cooling system comprising a vaporization-condensation circuit i1 having a vaporization portion i8 in heat exchange relation with the absorbent chamber of the boiler-absorber and a condensation portion i9 provided with heat dissipating fins and arranged-tin the duct F to be cooled by air. The cooling circuit 11 is charged with methyl chloride or other suitable heat transferring fluid capable of vaporizing in the vaporization chamber l8 and of llquefying in the condenser l9 and is provided with a motor-operated valve 20 for controlling the flow of liquid from the condenser to the vaporization chamber and is also provided with a collecting vessel 2| for storing the liquid when the valve is closed.

The operation of the refrigerating unit on 9.1-- ternate generating and absorbing periods iscontrolled by a suitable change-over device 22 constructed and arranged to deenergize the heater i and simultaneously to energize the motor of the valve to open the latter at the end of the generatin period and to deenerglze the motor of the valve 20 to close the latter and simultaneously to energize the heater It at the end of the absorbing period. For this purpose, the change-over device 22 includes a pair of levers 23 and 24 pivotally mounted as at 25 and operativeiy connected together by a toggle spring 25 to form a snap-action type control. The lever 23 carries a circuit-controlling contact 21 for cooperative engagement with one or the other of a pair of stationary contacts 29 and 30, respectively. Contact 29 is arranged on one side of the lever 23 and is connected by line 31 to the heater I6 which in turn is connected by line 32 to the positive line of the current source, while contact is arranged on the opposite side of the lever 23 and is connected by line 33 to the motor of the valve 20 which in turn is connected by line 34 to the positive line of the current source.

The lever 24 is disposed between a pair of limiting stops or abutments 35 and 35 and is movable from one abutment to the other and vice verse by a reciprocatable rod 31 actuated by the cxpansible bellows 38 or other movable element of a thermostat responsive to the temperature of the boiler-absorber H by means of a thermostat bulb 39 and operating against a counterbalancing force provided by a spring 40. A centering spring 4| cooperates with the lever 24 to maintain the latter normally in engagement with one or the other of the abutments 35 and 36. In this manner, the circuit-controlling lever 23 of the change-over device 22 will be shifted from one of its circuit-closing positions to the other with a snap-action at a critical temperature attained during the generating period of the unit respectively to interrupt operation of the heating means 16 and open the valve 25 to initiate operation of the cooling means 11 and will be shifted from its second-named to its first-named circuit-closing position with a snap-action at another critical temperature attained during the absorbing period of the unit respectively to initiate operation of the heating means i5 and close .the valve 25 to terminate operation oi the cooling means I1.

Inasmuch as the refrigeratin unit produces refrigeration intermittently, that is, during the absorbing periods, the evaporator 14 may be associated with a brine tank or other well-known cold hold-over means arranged in the storage space 15 of the cabinet [0 so as to prevent or reduce the temperature fluctuations occasioned by the flow of comparatively warm refrigerant liquid to the evaporator during the generating periods of the unit.

In order to compensate for changes in the refrigeration demands. it is desirable'to vary the rate of circulation per unit of time of the refrigerant through the system. For this purpose, I have shown as an example a rheostat 45 having a control arm 45 connected by line 41 to the negative line'of the current source and movable across resistance 48 connected by line 48 to the contact 21 of the movable control lever 23 of the change-over device 22 so as to vary the heating rate of the heater l6 and. in consequence thereof, vary the rate of liberation per unit of time of the refrigerant from the absorbent during the generating periods of the unit.

The resistance 48 of the rheostat 45 is also connected by line 50 to a motor-driven tan assembly 51 associated with the duct F and operating to control the rate of how of air over the condensers i2 and 18. In this manner, upon movement of the control arm 45 across the resistance 48, the operating speed of the motor-driven fan assembly 5i will be varied so as to vary correspondingly the capacity or output per 'unit of time of the condenser or heat dissipating part 12 for liqueiylng the refrigerant vapors during the generating periods and the capacity or output per unit of time of the secondary coolin system II for removing the absorption heat during the absorbing periods of the unit.

The rheostat 45 also controls the rate of energization or operating speed of another motordriven fan assembly 52 arranged to circulate the air in the storage space i5 in heat exchange relation with the evaporator or cooling unit 14 so as to control the capacity or output of the latter per unit of time. The fan assembly 52 is connected by line 53-43 with the contact 35 of the change-over device 22 and by line 54 with the positive line of the current source so as to be energized during the absorbing periods of the unit.

Thus, the heating rate or the heater l5 controlling the rate of liberation per unit of time or the refrigerant vapors from the absorbent during the generating periods, the operating speed of the motor-driven fan assembly 5| controlling the rate of condensation per unit of time of said refrigerant vapors during the generating periods and the cooling rate per unit of time of the secondary cooling system 11 during the absorbing periods, and the operating speed of the motordriven tan assembly 52 controlling the rate of circulation per unit of time of the air in the storage space l5 in heat exchange relation with the evaporator or cooling unit [4 are all controlled by the rheostat 45.

The control arm 450i the rheostat 45 is actuated by the expansible bellows or other movable elements 55 and 56 of thermostats 51 and 58, re-

spectively, the former responsive to the temperature in the storage space l5 of the cabinet Ill by means of a thermostat bulb 59 and the other thermostat responsive to the ambient air temperature by means of a thermostat bulb 55. Each of the expansible bellows 55 and 56 operates against a counterbalancing force or pressure provided by a spring or the like 5| adjustable by means of a nut 62 or other suitable means to set the desired operating temperatures of the respective thermostats 51 and 53.

The cabinet thermostat 51 is constructed and arranged to operate over a comparatively short range of temperatures corresponding to the tem-,

perature fluctuations in the storage space 15 while the room thermostat 58 is constructed and arranged to operate over a comparatively long range of temperatures corresponding to the temperature fluctuations oi the ambient air and each thermostat operates within its respective temphave been set,by the adjusting nut 82 so that the control arm 48 of the rheostat 45 occupies the point of highest resistance H on the resistance coil 48 as shown in Fig. 1, the heater i8 and the fan assembly will be energized at a comparatively low rate during the generating periods of the unit and such fan assembly together with the fan assembly 52 will be energized at a comparatively low rate during the absorbing periods of the unit. Consequently, the refrigerant will be circulated through the system at a comparatively low rate per unit of time to take care of the heat leakage through the insulated walls of the cabinet IO. In other words, the unit will operate with comparatively long generating and absorbing I periods.

Upon temperature rise in the cabinet, that is,

the storage space l5, occasioned by opening the door of the cabinet or by placing more foodstuffs in the storage space to be cooled, the control arm 65 of the rheostat 45 will be moved by the expansible bellows 55 of the cabinet thermostat 51 across the resistance 48 toward the point of lowest resistance L to increase correspondingly the heating rate of the heater i6 and the operating speed of the fan assembly 5! during the generating periods of the unit and the operating speed ofsaid fan assembly and that of the fan assembly 52 during the absorbing periods so as to increase the rate of circulation of the refrigerant per unit of time and restore the temperature in the storage space it to the desired level by shortening the cycles of the unit.

Likewise, upon a rising room or ambient temperature, the control arm 56 will be moved by the expansible bellows 56 of the room thermostat 58 across the resistance 48 toward the point of lowest resistance L to shorten the cycles of the unit and thereby increase the rate of circulation of the refrigerant per unit of time to take care of the increased heat leakage through the heat insulated walls of the cabinet.

The cabinet thermostat 51 and the room thermostat 58 may operate together to move the control arm 46 across the resistance 48 from the point of highest resistance to the point of lowest resistance or such thermostats may operate independently of one another depending upon the nature of the temperature changes, that is, whether occurring in the storage space of the cabinet ill in which event the cabinet thermostat 51 will operate, or whether occurring outside the cabinet in'which event'the room thermostat 58 will operate, or whether occurring both inside and outside the cabinet in which event both thermostats 51 and 58 will operate.

It will thus be seen from the foregoing that the heating rate of the heater l6 for that part of the refrigerating system in which the refrigerant is generated or liberated from the absorbent; the cooling rate of the cooling fluid for those'parts of the system in which the refrigerant is liquefied and is absorbedyrespectively, and the output per unit of time of that part in which'the refrigerant is evaporated are all controlled in accordance with the refrigerating demands, that is, in accordance with the temperature in the space being cooled and the temperature outside the said space so that upon change in any one or both of said temperature conditions, the capacity or output per unit of time of each of the parts of the refrigerating system will be altered automatically to efl'ect circulation of the refrigerant at the requisite rate per unit of time to maintain the desired temperature in the space being cooled. In this manner, the highest coefficient of performance of the unit will be obtained during normal operating conditions and as such conditions prevail during the greater part of the operating time of the unit, the average coefficient of perform-ance of the refrigerating unit will be comparatively high.

It may be desirable, especially where the evapo-. rator or cooling unit of the refrigerating apparatus is constructed and arranged to cool an ice freezing or other low temperature chamber, to

. employ a third thermostat responsive to the temperature of such freezing chamber, or to the evaporator temperature, to actuate the rheostat or other control for the several overloading or capacity-varyingmeans so as to compensate for temperature changes in said freezing chamber occasioned by placing water or comestibles therein to be frozen.

Such an arrangement is shown in Fig. 2 in connection with a pair of intermittent absorption refrigerating units A and B associated with a. household refrigerator cabinet H0. Inasmuch as the refrigerating units are similar to one another, only the various parts of the unit A will be described in detail, it being understood that unit B has similar pars which for convenience have been designated by the same reference numerals used for the corresponding parts of unit A but distinguished therefrom by the addition of a prime.

As in the installation described in connection with Fig. 1, each unit comprises a closed system formed by a plurality of interconnected parts including a boiler-absorber or generator-absorber H i containing strontium chloride or other suitable absorbent capable of absorbing ammonia I orother refrigerating fluid employed in the system, a condenser H2 provided with heat dissipating fins and arranged in a. flue space or duct 1 F to be cooled by air, a receiving vessel H3 embedded in the thermal insulation of the cabinet H0, and an evaporator 4. However, in the present instance, the evaporator H4 has a cooling or evaporator part 90 in heat exchange relation with an ice freezing or low temperature compartment 9| in. the cabinet ill] and has another cooling or evaporator part 92 preferably provided with cooling fins and arranged to cool the air in the storage space N5 of the cabinet. If desired. the freezing compartment 9| may be thermally insulated from the storage space 5, so as to reduce or prevent the heating up influence on the freezing compartment of the air in the storage space H5 inasmuch as the average temperature in the latter is higher than that maintained in the freezing compartment 9|.

Each unit is provided with an electrical heat-, ing element N16 or other suitable heating means to supply the necessary heatto the boiler-absorber during the generating period to effect liberation of the refrigerant from the absorbent.

The refrigerant vapors liberated during this period of the unit are condensed or liquefied in the condenser H2 under the cooling action of the cooling air and the refrigerant liquid is collected in the receiver H3 and evaporator II4.

Each unit is also provided with suitable cooling means to cool the boiler-absorber during the absorbing period so as to effect evaporation of the refrigerant liquid in the evaporator and absorption of the vapor by the absorbent and thus produce refrigeration in the freezing compartment 8| and in the storage space II5 of the cabinet III]. For this purpose, I have shown a secondary cooling system II'I common to both units and comprising a vaporization condensation cooling circuit having a vaporization portion II8 in heat exchange relation with the absorbent chamber of .the boiler-absorber III of unit A and a similar vaporization portion 8' in heat exchange relation with the absorbent chamber of the boiler-absorber III' of unit B and a condensation portion II8 provided with heat dissipating fins and arranged in duct F to be cooled by air. The secondary cooling system III is charged with methyl chloride or other suitable heat transferring fluid capable of vaporizing in the vaporization chamber II8 or II8 and of liquefying in the condenser H8 and is provided with a motor-operated valve I28 for controlling the flow of liquid from the condenser II8 to the vaporization chamber H8 and with another mo-v tor-operated valve I 28' for controlling the flow of liquid from the condenser II8 to the vaporization chamber 8'. ,The secondary cooling system is also provided with a collecting vessel I2I interposed in the circuit between the condenser H8 and the valves I20 and I2II"at a suitable level with respect to the vaporization chambers H8 and III.

In the installation shown, the two units A and' by means of thermostat bulb I38. A centering spring I4'I cooperates with the lever I24 to maintain the latter normally in engagement with one or the other of the abutments I38 and I38.

In this manner, the circuit-controlling lever I23 of the change-over device I22 will be shifted from one of its circuit-closing positions to the other with a snap action at a critical temperature attain'ed during the generating period of a respec-- tive unit to interrupt operation of the heating means and initiate operation of the cooling means of said unit and simultaneously interrupt operation of the-cooling means and initiate operation of the heating means of the other unit for operation of said units in out-of-phase relationship with respect to one another.

As in the installation heretofore described in connection with Fig. 1, the rate of flow of air over the primary and secondary condensers in the duct F is controlled by a motor-driven fan assembly I8I. Moreover, the operating speed of the fan assembly I5I together with the heating rate of the heater IIG for the boiler-absorber III of unit A as well as the heating rate of the heater 8' for the boiler-absorber III' of unit B are controlled by a rheostat I45 having a control arm I48 connected by line I41 to the negative line of the current source and movable across a resistance I48 connected by line I48 to the line I29 interconnecting one of the contacts I28 and one of the contacts I28 of the change-over device I22. The motor-driven fan assembly I8I is connected by line I88 to the line I28 and is also connected to the positive line of the current source so that the circuit is made through the rheostat I45.

The control arm I48 of the rheostat I45 is oneratively connected to a reciprocatable rod I82 operation being automatically controlled by a change-over device I22 having a pair of levers I23 and I24 pivotally mounted as at I 25 and operatively connected together by a toggle spring I26 to provide a snap-action type control. The lever I23 carries a circuit closing contact I21 for cooperative engagement with a pair of contacts I28 arranged on one side thereof and with a similar pair of contacts I28 arranged on the opposite side thereof. One of the contacts I28 of one pair and one of the contacts I28 of the other pair are connected togetherby line I28. The other one of the contacts I218 of the first-named pair is connected by line I3I to the heater II8 which in turn is connected to the positive line of the current source and the aforesaid contact is also connected by line I33 to the motor of the valve I28 which is also connected to the positive line of the current source. The other one of the contacts I28 of the second-named pair is similarly connected to the heater I I8 and the motor of the valve I28 by lines I3I' and I33, respectively, each of which is connected to the positive line of the current source as shown.

The lever I24 of the change-over device I22 is disposed between a pair of limiting stops or abutments I38 and I36 and is movable from one abutment to the other and vice verse. by the expansible bellows or other movable elements I38 and I38, respectively, of a pair of oppositely disposed thermostats, the former responsive to the temperature of the boiler-absorber III by means of thermostat bulb I38 and the other responsive to the temperature of the boiler-absorber III' actuated by the expansible bellows or other movable elements I53, I54 and I55 of three thermostats I58, I51 and I58, respectively, the first bein responsive to the temperature in the storage space II! of the cabinet by means of thermostat bulb I88, the second being responsive to the temperature in the freezing compartment 8i of the cabinet by means of thermostat bulb I88, and the third being responsive to the ambient air temperature by means of thermostat bulb I8I. Each of the expansible bellows I53, I54 and I55 operates against a counterbalancing force or pressure provided by a spring I82 adjustable by means of nut I83 to set the operating temperatures of the respective thermostats I58. I81 and I88.

The thermostats I58, I51 and I88 are set to operate at respectively different temperatures corresponding respectively to the normal temperatures in the storage space N5, the freezing compartment 8| and the ambient air and are constructed and designed to operate over respectively different ranges of temperatures corresponding respectively to the temperature fluctuations in the storage space I I5, the freezing compartment 8i and the ambient air.- Moreover,

each of the aforesaid thermostats is constructed and designed to operate within its respective temperature range to effect movement of the control arm '8 of the rheostat I45 across the resistance I48 between the point of highest resistance H and the point of lowest resistance L.

The operation of this embodiment of the invention will be obvious from the foregoing description together with the previous description in connection with Fig. 1, it being evident that the heating rate of the heating means for the boiler-absorber of each unit, the cooling rate of the cooling means for the primary condenser of each unit and the cooling rate of the cooling means for the boiler-absorber of each unit will allbe varied automatically upon temperature change of the ambient air, or in the storage space H5, or in the freezing compartment 9| to compensate for such temperature variations. Consequently, the refrigerating apparatus will have its highest coefficient of performance when operating under normal conditions or loads to meet the normal refrigeration demands.

Instead of having the room or ambient thermostat operate independently of the cabinet thermostat and/or the evaporator thermostat to actuate the movable element of the rheostat or other device controlling .the heating rate of the heating means for that part of the refrigerating system in which the refrigerant is liberated and the cooling rate of the cooling means for those parts of the refrigerating system in which the refrigerant is liquefied and is absorbed, respectively, it may be desirable and advantageous to have the cabinet thermostat or the evaporator thermostat selectively control the heating rate of said heating means and the cooling rate of said cooling means between a predetermined minimum and an increased "value determined by the room thermostat.

Such an arrangement is shown in Fig. 3 in connection with refrigerating apparatus similar to that heretofore described in connection with Fig. 2 and in which the same reference characters have been used to designate like parts in both figures.

In this embodiment of the invention, the heating rate of the heating means of each unit and the operating speed of the motor-driven fan assembly I5I controlling the capacity or output per unit of time of the primary condenser of each unit and the capacity or output per unit of time of the secondary cooling system are all varied by means of a rheostat or other suitable device I88. The control arm I8I of the rheostat I88 is connected by line I82 to the negative line of a current source and is movable across a resistance I83 between the point of highest resistance H and the point of lowest resistance L by the expansible bellows or other movable element I84 of a thermostat I85 responsive to the ambient air temperature by means of thermostat bulb I88. The expansible bellows I84 operates against a counterbalancing force provided by a spring I81 which sets the operating temperature of the thermostat I85.

Instead of being connected directly to the line I29 interconnecting one of the contacts I28 and one of the contacts I28 of the change-over device I22 as heretofore described in connection with Fig. 2, the resistance I83 is connected by line I88 to one of a pair of stationary contacts I89 arranged adjacent one side of the movable lever I98 of a circuit-controlling switch I9I. The

' other one of the pair of contacts I89 is connected by line I92 to the line I29 interconnecting one of the contacts I28 and I28 of the change-over device I22. Thus, the circuit through the rheostat I88 for the heaters '6 and H8 and the motor-driven fan assembly I5I is made by way of the switch I9I.

arranged on oneside thereof and also for coop erative engagement with another pair of contacts I91 arranged on the opposite side thereof.

One of the contacts I91 is connected by line I98 to a resistance I99 in the negative line of a current source while the other one of the contacts I91 is connected by line 288 to line I92.leading to the switch contacts I28 and I28 of the changeover device I22 to provide another circuit for the heaters H 8 and I I8 and for the motor-driven fan force provided by a spring or the like 288 so as to effect movement of the lever I95 within the limits of the stops 28I and 282 over a predetermined range of temperatures and shift the circuitcontrolling lever I98 of the switch I9I from one of its circuit-closing positions to the other with a snap-action at one predetermined cabinet or evaporator temperature and shift said lever from its second to its first-named circuit-closing position at another predeterminedcabinet or evaporator temperature. I

As in the installations previously described, the cabinet thermostat 284 is constructed and designed to operate over a comparatively short range of temperatures corresponding to the usual temperature fluctuations in the cabinet I I8 while the room thermostat I is constructed and designed to operate over a comparatively long range of temperatures corresponding to the room air temperature fluctuations in which the refrigerat- I ing apparatus is to be operated. I

. The operation of this embodiment of the invention is as follows:

With the cabinet or evaporator temperature at the desired level for which the thermostat 284 has been set so that the circuit-controlling lever I98 of the switch*I'9I occupies the position shown v conditions of the refrigerating apparatus.

Upon temperature rise in the cabinet or in the evaporator occasioned by opening the door of the cabinet or placing more foodstuffsin the storage space H4 to'be cooled, or placing water or comestibles in the freezing compartment 9| to be frozen, or by rising room temperature which affects the rate of heat leakage through the insulating walls of the cabinet II8, the lever I of the switch I9I will be moved from its abutment 282 toward its abutment 28l by the expansible bellows 283 of the thermostat 284. when the aforesaid lever I95 moves past dead center of the switch I9I, the lever I98 will be shifted with a snap-action by the toggle spring I04 to the position shown in full lines in the drawing to interrupt the circuit through the resistance I99 and to close the circuit through the rheostat I80 so as to energize the heaters H8 and H8 and the fan assembly I5l at an increased rate per unit of time determined by the ambient air temperature as affecting the position of the control arm I8I relative to the resistance I83.

As soon as the cabinet or evaporator temperature is restored to the predetermined level for which the thermostat 204 has been set so that the lever I90 has been moved from its abutment l toward its abutment 202 and has reached -a position past dead'center of the switch I8I,

the lever I90 will be shifted to its position shown by the dot-and-dash lines to interrupt the circuit through the rheostat I80 and close the circuit through the resistance I 99 to energize the heaters H8 and H6 and the fan assembly Iii at a comparatively low rate per unit of time during the generating periods of the respective units and energize said fan assembly at the aforesaid comparatively low rate per unit of time during the absorbing periods of the respective units.

Thus, the cabinet thermostat 204 operates to 'vary the heating rate of the heaters H8 and I I8 and the operating speed of the fan assembly III between a predetermined minimum through resistance I99 and a variable maximum through rheostat I80 in accordance with the temperature conditions in the cabinet IIO thermostat I86 operates to determine the value of said maximum heating rate of the heaters H8 and H8 and such maximum operating speed of the fan assembly iii in accordance with the ambient air temperature. Consequently, as in the installation previously described, the refrigerating apparatus will have its highest coefflcient of performance when operating under normal conditions and. as such conditions will be prevalent for the greater part of the operating time of the refrigerating apparatus, the average coeflicient of performance of the machine will be comparatively high.

It will thus be seen from the foregoing description of the fundamental principle underlying the invention that I have provided a new and improved control for absorption or adsorption type refrigerating apparatus by means of which not only the heating rate per unit of time of the heating means for that part of the refrigerating system in which the refrigerant is generated but also the cooling rate per unit of time of the cooling means for that part of the refrigerating system in which the refrigerant is liquefied: and/or the rate of heat transferred per unit of time between-that part of the refrigerating system in which the refrigerant is evaporated and the space being cooled; and/or the cooling rate per unit of time of the cooling means for that part of the refrigerating system in which the refrigerant is absorbed or adsorbed and as a consequence the capacity or output per unit of time of each of said parts will be varied automatically in accordance with the demands for refrigeration.

Although I have shown and described the in vention in connection with an electrical control for varying the capacity or output per unit of time of the several parts of the refrigerating apparatus. it will be obvious to those skilled in the art that the invention can be practiced by any other well known type of control. Therefore.

12 of control illustrated except as limited by the appended claims.

While I have shown and described the invention in connection with intermittent absorption refrigerating apparatus, the same is equally applicable to absorption refrigerating apparatus of the continuous type and is also equally applicable to adsorption refrigerating apparatus. Consequently, it is to be understood that the use of the expressions "absor absorbent," "absorption," etc. in the foregoing specification and in the following claims is intended to include the corresponding expressions applicable to adsorption refrigeration.

From the foregoing it is believed that the constructlon, operation and advantages of the inand the room it is to be understood that the invention is not vention will be readily understood by those skilled in the art without further description, it being borne in mind that numerous changes may be made in the details disclosed without departing from the spirit of the invention as set out in the following claims.

What I claim is:

1. Absorption type refrigerating apparatus including a generator-absorber, an air-cooled condensed, and an evaporator arranged to form a closed system for circulation of a refrigerating fluid; heating means for said generator-absorber; a vaporization-condensation circuit for cooling said generator-absorber having a vaporization portion in thermal exchange relation with the generator-absorber and a condensation portion cooled by air; a valve in said circuit for controlling the flow of liquid from said condensation portion to said vaporization portion; means cooperating with said valve and heating means for controlling the alternate heating and cooling of said generator-absorber; means for varying the heating rate of said heating means; means for varying the rate of flow of air over said condensed and said condensation portion; and means for controlling said first-named and second-named rate-varying means in accordance with a plurality of temperature conditions including one affected by said evaporator, and another affected by temperature of cooling air for said condenser and said condensation portion.

2. Absorption type refrigerating apparatus insaid generator-absorber; means for varying the heating rate of said heating means; means for varying the rate of flow of air over said condenser and said condensation portion; and means responsive to a plurality of temperature conditions including a temperature affected by said evaporator, the temperature of cooling air for said condenser and said condensation portion, and the temperature of said evaporator constructed and arranged to control said first-named and secondnamed rate-varying means in accordance with change in any one of said temperature conditions.

3. A refrigerating system comprising a refrig- 13 erant vapor-supplying means, an ambient aircooled condenser, a refrigerating evaporator, con: nections providing communication between said vapor-supplying means, condenser and evaporae tor, a heater for said vapor-supplying means, con-.

trol means for varying the heating rate of said heater, means for varying the capacity of said condenser, thermostatic means responsive ,to a

temperature, the other thermostatic means is responsive to the evaporator temperature, and a third thermostatic means is provided responsive to the temperature of the air refrigerated by said evaporator, saidoperating means being responsive to all three thermostatic means.

5. Apparatus according to claim 3 further provided with refrigerated air circulating means for varying the rate of flow of air in thermal exchange relation with the evaporator, one of said' thermostatic means being responsive to ambient air temperature, the other of said thermostatic.

means being responsive to the evaporator temperature, and thermostatic means being. provided responsive to the temperature of the air circulated in contact with the evaporator, said operating means being responsive to all three thermostatic means and being capable of controlling said heatvarying means, said condenser capacity-varying means and said refrigerated air circulating means. 6. Apparatus according to claim 3 in which the refrigerant vapor-supplying means is a generator-absorber and the apparatus is provided with cooling means for the generator-absorber capable of being controlled so as to vary the cooling effect of said cooling means, said cooling means being controlled by said operating means.

7. Apparatus according to claim 3 further provided with a second refrigerant vapor-supplying means, a second ambient air-cooled condenser, a second refrigerating evaporator, and a changeover device capable of effecting heating of each of said vapor-supplying means intermittently and in vout-of-phase relation to one another. 8. Apparatus according to claim 3 in which the control means for varying the heating rate of the heater comprises two control elements, one of said elements effecting operation of the heater l4 at a uniform rate equivalent to the normal refri eration demand of the system and the other element effecting variable operation of the heater responsive to said thermostatic means, a changeover device being provided which is responsive to operation of atleast one of said thermostatic means and capable of establishing control of the heater by said variable control element upon an 1 increase in refrigeration demand on the system.

9. In absorption refrigerating apparatus com prising a generator-absorber capable when heated of liberating warm refrigerant vapor and when subsequently cooled of absorbing refrigerant vapor, heating means capable of supplying sufllcient heat to the generator-absorber to effect liberation of refrigerant vapor therefrom, a condenser disposed in a cooling medium and capable of cooling the warm refrigerant vapor liberated from the generator-absorber and thereby effecting condensation of said vapor to the liquid state, and an evaporator disposed in a space to be refrigerated and serving as a receiver for liquid refrigerant capable of eflecting refrigeration upon evaporation of liquid refrigerant therefrom as the evaporated refrigerant vapor is absorbed by the generator-absorber, the improvement which comprises heat control means capable of regulating the rate of heat input from said heating means to the generator-absorber. circulating means capable of effecting controlled circulation of the condenser cooling medium about the condenser,

' thermostatic means responsive to the temperature of the condenser cooling medium, thermostatic'means responsive to the temperature within the refrigerated space, and interconnecting means-capable of combining the responses from said thermostatic means in such manner as to provide a single response output upon a change in refrigeration demand, the heat control means and the circulating means being operatively associated with and controlled by said single response output of the interconnecting means.

REFERENGES CITED The following references are of record in the file of this patent: V a

UNITED STATES PATENTS 2,282,884 H Taylor May 12, 1am

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