US2022469A - Refrigerating apparatus - Google Patents

Description

Patented Nov. 26, 1935 UNITED STATES PATENT OFFICE REI'BIGEBATING APPARATUS Application December 27, 1932, Serial No. 648,940 Renewed April 10, 1934 14 Claim.

This invention relates to refrigerating apparatus and particularly to the control of such apparatus.

One of the objects of the present invention is to provide a refrigerating system which automatically and normally maintains the desired refrigerating temperature for general refrigerating purposes and which will provide increased cooling automatically when it is desired, such as when ice cubes are to be frozen or comestibles are to be congealed in the evaporator of the system, and which will automatically provide increased temperature of the evaporator at predetermined timed periods to effect defrosting of the evaporator.

Another object of my invention is to provide an improved refrigerating apparatus or system, including means which automatically modifies operations of the apparatus in response to certain demands or requirements placed upon the apparatus or in response to certain conditions of the apparatus, which will function automatically, to give preference to the effectiveness of one of the automatically operated devices included in the system without interfering with continued operation of the system under the influence of that device and without interfering with subsequent operations of the other or both of the automatically operated devices.

In carrying out the foregoing object, it is a further object of my invention to provide a refrigerating system or apparatus wherein there is included in the system a means for lowering the temperature of the evaporator automatically, in response to the placing of a substance to be congealed or frozen in thermal association with the evaporator, and wherein there is also included in the system a means for effecting defrosting of the evaporator automatically at predetermined timed intervals, with means for automatically and temporarily rendering the defrosting means ineffective when the means for causing a lower temperature of the evaporator, for quickly freezing 'a substance, is rendered effective.

Further objects and advantages of the present invention will be apparent from the following descrip ion, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 discloses a refrigerator cabinet shown in cross section and having my improved refrigerating system, shown diagrammatically, installed therein;

Fig. 2 is a sectional view taken on the line 22 of Fig. 3 of a control switch mechanism included in the refrigerating system;

Fig. 3 is a top view of the control switch shown in Fig, 2;

Fig. 4 is an enlarged sectional view of a mag- 6 netically operated valve included in my improved refrigerating system;

Fig. 5 is a fragmentary sectional view, taken on the line 5-5 of Fig. 1, of a portion of a clock or chronometric device also included in the sys- 10 tem; and

Fig. 6 is a fragmentary elevational view of a portion of the clock or chronometric device shown in Figs. 1 and 5.

Referring to the drawings, for the purpose of 15 illustrating my invention, there is shown in Fig. 1 thereof a compressor 20 for compressing refrigerant, such as sulphur dioxide contained in the refrigerating apparatus or system, and for forwarding the refrigerant to the condenser 2i 20 where the compressed refrigerant is liquefied and collected in a receiver 22. From the receiver 22 the liquid refrigerant is forwarded through the supply conduit 23 to an evaporator 25 disposed in the refrigerator cabinet. The evaporator 25 2 returned to the compressor through the gaseous 35 refrigerant or return conduit 26. The compressor 20 is driven by an electric motor 21 through suitable belt and pulley connections 23.

The electric motor 21 is supplied with electric 4 energy through an electric circuit which will be hereinafter more fully described.

The evaporator 25 includes a header having a plurality of ducts depending therefrom to define a freezing zone. A sleeve or support 30 is supported within the freezing zone of the evaporator 25 and is adapted to receive and support a tray or receptacle 3!. Evaporator 25 is located in an upper corner of an insulated compartment 32 of a refrigerator cabinet 33. The refrigerator cabinet may also include a lower machine compartment, closed by the door 34, and in which the refrigerant liquefying and circulating unit of the system is ordinarily housed. The insulated compartment 32 of cabinet 33 is divided into a food storage compartment and a cooling unit 55 compartment by any suitable partitioning means such as the baiile or partition 36. Partition is provided with an opening 3! in the upper portion thereof and an opening 38 in the lower portion thereof to permit the ingress and egress of air circulated from the cooling unit compartment to the food storage compartment.

A control switch mechanism or device 40 is connected by a conduit 4! with a thermostat bulb 42. Bulb 42 is located preferably in the upper portion of the food storage compartment 32 of cabinet 33 and is responsive to the temperature in compartment 32 and consequently of the evaporator 25. The control mechanism 40 and the thermostat bulb 42 connected therewith, normally maintains the insulated compartment 32 and consequently evaporator 25 between predetermined temperature limits by opening and closing an electric circuit leading to the motor 2! of the refrigerant liquefying and circulating unit, to provide alternate operating and idling periods of the compressor 20 according to the temperature in compartment 32, and consequently to the temperature of the evaporator 25. The foregoing description and disclosure of a refrigerating apparatus or system is conventional and is well-known to those skilled in the art of refrigeration. For this reason the description of the refrigerating system is made brief and the system is only diagrammatically disclosed.

However, since my invention relates to the fully automatic control and function of a refrigerating system or apparatus which includes therein means for automatically modifying the operation of the refrigerant circulating unit or for reducing the temperature of the evaporator of the system below its normal low temperature limit in response to the placing of a substance in the evaporator to be congealed or frozen and also includes means operated at predetermined time intervals automatically for defrosting the evaporator of the system, to periodically remove frost or condensation of moisture collected on the evaporator from the circulating air within the refrigerator cabinet, other auxiliary devices and a somewhat more elaborate electrical control circuit is essential to insure fully automatic and proper functioning of the system according to the objects of my invention. Therefore the refrigerating system includes a device for modifying the operation of the refrigerant liquefying and circulating unit or for modifying the normal setting of the control mechanism 40 automatically to lower the temperature of the evaporator below the normal low temperature limit thereof in response to the placing of a receptacle, such as the tray designated at 3! containing a substance to be frozen, in the freezing zone formed by the evaporator 25 or in the sleeve 30. In the present disclosure this device is incorporated in the control mechanism 4|! and includes a conduit 44 connected with a thermostat bulb 4s. Bulb 45 is secured in mmmate thermal contact with the support or sleeve 30 upon or in which the tray 3i is adapted to be placed. The construction of this auxiliary device will be hereinafter more fully described and a description of its operation will accompany the description of the operation of the system. The means for effecting automatic defrosting of the evaporator 25 of the refrigerating system at predetermined periods includes a device generally designated at 41 in Fig. 1 and associated with a clock or chronometric device generally designated at 48. The device 41 is connected in series with the refrigerant conduit 2| forming the condenser and the device 45 is electrically connected with the device 41. A conduit 43 has one end thereof connected with the device 41 and has its other end leading to and communicating with the interior of the evaporator 25 preferably above the liquid refrigerant level therein. The construction of the auxiliary devices 41 and 45 for effecting defrosting of the evaporator will be hereinafter more fully described and a description of their operation will accompany the description of the operation of the system.

The thermal responsive means associated with the conduit 4| and bulb 42 of the system for actuating the control mechanism or device 40 comprises a hollow metallic bellows 54 (see Figs. 2 and 3) which is sealed at the top and which is connected at the bottom to the conduit 4i. Conduit 4i, bulb 42 and bellows 54 thereby provides a. closed thermal system containing any suitable volatile fluid which vaporizes and liquefles or expands and contracts due to temperature changes for actuating the control 45. An operating lever pivoted on ears 55 of the elevated platform 51 follows the movements of bellows 54 by being pivoted thereto by a pin 53. A double lever 59 straddles the lever 55 and is pivoted thereto by the pin 5|. One end of the lever 59 is connected to one of the switch contacts 52 by a link 53. The cooperating switch contact 54 is mounted on the base 55 of the control device. A snap action of the contact 52 with respect to its corresponding contact 64 is provided by a cam system which includes a steel nose 55, fastened to the other end of the lever 59, against which a roller 61 is biased by a carrier 58 and a spring 59. As the pressure increases within the flexible metallic bellows 54, the latter expands and since the lever 55 is pivoted to this bellows by pin 55 and fulcrumed to the supporting frame of the device as at 55, it is evident that the bellows will raise the operating lever 55.

The upward movement of the lever 55 is resisted by a yieldable adjustable system comprising a coil spring carried within an adjustable casing I2 and bearing against a plunger I3 which acts against the extremity I4 of lever 55. When the pressure decreases and the bellows 54 collapses, the downward movement of lever 55 will be resisted by a coil spring I5 whose tension may be regulated by nuts 16 carried on a vertical threaded rod II pivoted to lever 55. A balancing spring I3 adjusted by nuts I! is used on the opposite side of the base 55 of the control device for resisting the tension of the spring I5. The springs I5 and I8 and the resilient adjusting system comprising the plunger I3 and the adjusting cap I2 are provided for preferably so adjusting to produce what may be termed a normal predetermined adjustment, that is, for maintaining a pressure corresponding to a particular temperature in the thermal system 54, 4| and 42 which is ordinarily suitable under normal conditions for everyday operation of the evaporator in which the system is used.

The extremity I4 of the lever 55 bears against the plunger l3 only on the upward action of the lever 55. After lever 55 begins to descend the extremity I4 does not touch the plunger 13. Thus the plunger I3 effects the starting temperature but not the stopping temperature. The cap I2 is therefore'a starting adjustment. The temperature provided by the mechanism thus described is sufficient to maintain a substance contained in the evaporator in a frozen state after it has been frozen by the evaporator or is willcient to cool to the desired temperatures comestibles ordinarily stored in the insulated food compartment 82 of the cabinet 88. The control mechanism including the parts heretofore described is substantially identical to the control mechanism disclosed in the patent to Otto M. Summers. No. 1,802,488. issued April 28-, 1931.

Since it is desirable to cause continuous operation or longer operating periods of the refrigerant liquefying and circulating unit instead of a plurality of short operating periods to rapidly reduce the temperature of the evaporator 25, and consequently the freezing zone formed in the evaporator, below their normal low temperature limit in event the evaporator or the freezing zone formed therein increases in temperature abnormally, I have provided means for modifying the operation of the refrigerant liquefying and circulating unit. The control means 88 is usually adjusted at the factory. or in the field by experienced service men, for such normal operation, by suitably tensioning the springs 15 and 18 as well as the resilient adjusting system 12 and 18. and in such condition the lever 55 will have its upward and downward movement resisted so that it will open and close the circuit of the driving motor 21 only at the maximum and minimum temperature points for which the tension corresponds. By interposing a resistance to the descent of the lever 55, the operation of the switch contacts 82 and 88 will be delayed so that the system will operate continuously or will continue operating for a longer period of time, thus prolonging the cooling cycle of the system. Likewise if the resistance to the descent of the lever 55 is increased, it will require a greater effort on the part of the diaphragm or bellows 58 to pull the lever 55 down into contact breakingposition. (The descent of the lever 55 causing the raising of contact 82 away from the contact 88 thus breaking the circuit.)

Therefore the auxiliary device, included in the system for automatically modifying the action of the control switch or for automatically interposing such a resistance to the control switch when it is desired, which communicates with the conduit 88 and bulb 85 includes a flexible bellows 8| fastened to the base 85 of the control device or mechanism 88 (see Figs. 2 and 3). The bellows 8|, conduit 88 and bulb 85 provides a closed thermal system containing any suitable volatile fluid which vaporizes and liqueiles and expands or contracts due to temperature changes. A pair of springs 82 have their lower ends attached to the base 85 of the control device 88 and have their upper ends connected to a cross strip 88 which rests on and may be fastened to the top of the bellows 8|. 82 normally maintain the bellows 8| in a contracted or collapsed position during normal operation of the system and therefore this bellows is out of contact with the control lever 55 and is consequently ineffective for adding resistance to the descent of lever 55.

Another electrical switch, comprising a closed glass tube 88 containing a small quantity of mercury, is associated with the control mechanism 88 and is adapted to be actuated only by movement of or expansion and contraction of the flexible bellows 8|. The mercury tube 88 of this switch is pivotally mounted at its central portion by a yoke or shaft 81 to ears 88 formed on a support 88 secured to and extending upwardly from base 85 of the control device 88.

Springs An actuating arm or finger 8|. secured to and adapted to move with the bellows 8|. engages and actuates the mercury tube 88 about its pivot 81 upon movement of the bellows 8|. It is to be understood that the actuation of the mercury 5 tube 88 is preferably a snap action for instantly moving the tube from its one tilted position to its other tilted position. Obviously the finger 8|,

in order to permit snap action of the tube 88, will be provided with an elongated opening to 10 permit free movement of tube 88 therein entirely from one tilted position to the other. Movement of the tube 88 from one tilted position to another causes the flow of mercury contained in the tube from one end thereof to the other. A pair of electrical contacts 82 and 88 extend through and are sealed to the wall at one end of the tube 88 and a second pair of electrical contacts 88 and .85 extend through and are sealed to the wall of the tube 88 at the other end thereof. One or the other of these pairs of electrical contacts, according to the position of the tube 88, are at all times bridged by the mercury within the tube. The contacts 82, 88, 88 and 85 are connected by wires 88, 81, 88 and 88 respectively to a terminal block IIII secured to the base 85 of the control 88 and are in turn connected to an electrical circuit to be hereinafter fully described.

The device 81 which is associated with the auxiliary device 88 for effecting defrosting of the evaporator and which is actuated automatically at predetermined time intervals in accordance with the operation of the chronornetric means or clock 88 (see Fig. 1) includes a valve I85 disposed within the housing I88 of the device 81 (see Fig. 4). Housing I88 includes a passage I81 extending therethrough and forming a part of the condenser conduit 2I. The housing I88 is also provided with a passage I88 which is connected to the conduit 88 leading to the interior of the evaporator 25. Passage I88 is adapted to communicate with the passage I81 and consequently with the high pressure on the interior of the condenser 2| but is normally closed off from passage I81 and condenser 2| by the valve I85. A plunger or enlarged portion I88 is formed on the top of valve I85 and thus plunger I88 is of sumcient weight to normally maintain the valve I85 in its closed position to seal the conduit 88 from the high pressure in the system, during operation of the system to produce refrigeration, due to the small area of the valve I85 which is exposed to the pressure of refrigerant contained in the system. However in order to overcome the force exerted upon the valve I85 by the weighted plunger or portion I88, I provide a magnet or solenoid II8. Solenoid 8 may be of any conventional design and it is to be understood that when this solenoid is energized the plunger or portion I88 will be attracted by the solenoid and will be elevated to raise the valve I85 from its seat. Solenoid H8 is adapted to be connected to the clock or chronometric device 88 and to the electrical circuit to be hereinafter fully described, by attaching wires to the terminals III and 2 provided on the solenoid.

The means 88 for controlling predetermined timed periods of defrosting of the evaporator 25 of the refrigerating system includes a conventional clock or c'hronometric mechanism (not shown) disposed within the casing 5 (see Fig. 5) and this mechanism may be of any suitable construction which constructions are well-known to those familiar with the art to which such mechanism belongs. The mechanism of the clock or chronometric device 48 located within the easing I I may, for example, be of the spring-wound type or it may be operated or driven by being connected in an electrical circuit. In either event it is to be understood that the operation of the mechanism disposed within the casing II8 of the means 48 is continuous irrespective of operations of the refrigerating system. A shaft II8 (see Fig. 5) of insulating material is preferably connected to the shaft of the hour hand of the clock or chronometric mechanism and is continuously rotated by the continuous rotation of the hour hand shaft. This shaft II8 extends through an opening H1 in a wall II8 of the means 48 and has a metallic finger H8 secured thereto by a screw or nut I2I. A metallic collar I22 is loosely mounted on shaft H6 and is provided with an extension I23 which serves to provide a terminal for connecting a wire to the collar. Since the collar I22 is loosely mounted upon shaft H8 and is not rotatable by shaft I I8 a spring I24 disposed between the collar I22 and an enlarged portion on shaft H6 is provided for holding the collar I22 in contact with the hub or finger II9 during rotation of shaft IIB. Finger II9 carries a pair of brush contacts I28 and I21. Contact I28 engages a metallic member or substantially a ring I 28 secured to and insulated from the wall III of the device 48 in any suitable manner such as by the insulating material I29. It will be observed by reference to Fig. 6 of the drawings that ring I28 has a portion thereof cut away or omitted from its circumference thus providing the ring with ends I3I and I32. It will also be observed that ring I28 is provided with a terminal I88 to which a wire may be secured. Disposed laterally from the space provided between the ends I 3i and I32 and concentric with the ring I28 I provide a metallic conducting member I35 which is secured to the wall II8 by a terminal screw I88 and which is insulated from this wall by the insulating material I31. It is to be understood that member I35 is arranged in the space between the ends I3I and I32 of ring I28 and that contacts I26 and I21 are also arranged on finger II8 to insure that during the rotation of finger II8, by rotation of the hour hand shaft of the clock or chronometric mechanism within the casing H5, finger IIB will be in contact with either the conducting member I35, by engagement thereof by contact I21, or ring I28, by engagement thereof by contact I28, at all times (see Fig. 6). In other words when contact I28 on finger I I8 moves beyond the end I32, during rotation of the finger the contact I21 on finger II! will immediately engage or contact the member I35.

The electrical circuit interconnecting the control device 48 and the auxiliary devices 41 and 48 included in my system to insure fully automatic operation of the system as will be hereinafter more fully explained includes a wire I (see Fig. 1) leading from any suitable source of electrical energy to the contact 84 on the control switch or device 48. A wire I42 leads from wire I to the terminal block I8I, wire 88 and contact 82 of the mercury tube switch on the control device 48. A wire I43 leads from the terminal block MI, and consequently from contact 88 and wire 81 of the mercury tube switch, to the terminal connection I I I on the solenoid II8. From contact 82 on the control switch 48 there is a wire I44 leading to the driving motor 21 of the refrigerating system. The wire I48 connects the motor 21 with the terminal block I8I and consequently by wire 88 with contact 85 of the merciu'y tube switch. The

motor 21 is also connected with the terminal I88 of ring I28 on the device 48 by a branch wire I48 leading from wire I48. A wire I41 leading from the terminal block Ill and consequently from wire 88 and contact 84 of the mercury tube switch 5 on device 48 connects with the source of the electrical energy. A branch wire I48 leading from wire I41 connects with the terminal I28, formed on the collar I22 surrounding the shaft II8, of the clock or chronometric device. It will be noted that the terminal II2 on the solenoid III is connected by a wire I48 to the terminal screw I88 of the member I88 on the device 48. The electrical connections between the control switch 48 of the refrigerating apparatus and other auxiliary 18 devices included in my refrigerating system having been described I will now therefore proceed to describe the operation of the system under the influence of or the effectiveness of the various auxiliary devices.

In the operation of the system under the influence of thermostat bulb 42 and control switch 48 to maintain the evaporator 28 and consequently compartment 82 of the refrigerator cabinet 88 between normal predetermined refrigerating temperatures the motor 21 is caused to operate in response to the closing and opening of contacts 82 and 64 of the control switch 48. It is desired to herein point out that the thermostat 45 is ineffective for actuating mercury tube 80 switch during the maintenance of normal refrigerating temperatures in cabinet 88 and that the mercury tube switch will remain in the position shown in Fig. 2 of the drawings. The mercury tube switch while in this position completes the electrical circuit from the source of energy through wire I, wire I42, wire 88, contact 82, contact 88, wire 81 and wire I48 to the terminal III on solenoid H8 and from terminal II2 on solenoid H8 by wire I48 up to the member I88 and if the finger I I8 of the device 48 is not in contact with the member I88 this circuit so far completed is interrupted at this point and energization of the solenoid H8 is prevented. If then the temperature of the compartment 82 of the cabinet 88 increases above the predetermined desired limit the thermal system connected with the thermostat bulb 42 and including the flexible bellows 84 will become effective to actuate the switch 48 to cause contact 82 thereof to engage 50 its corresponding contact 84. Upon engagement of the contacts 82 and 84 the electrical circuit from the source of supply to the motor 21 will be completed through wire I4I, contact 84, contact 82, wire I44, wire I48, wire I48, terminal I88, ring I28 on the clock or chronometric device 48 contact I28, finger II8, collar I22, terminal I28, wire I48 and to the side of the power circuit or wire I41 opposite wire I. It is of course to be understood that the contact I28 on finger II8 of 80 the clock or chronometric device 48 must be in contact with the ring I 28 in order to complete the circuit to the motor 21 to cause its operation. In other words the motor 21 will not be caused to operate by the making of contacts 82 and 84 on 85 the control switch 48 as just described unless the finger II8 of the clock or chronometric device 48 is in a position over the ring I28; that is, in a position beyond that shown in the drawings wherein the finger H8 is over the conducting member I88.

Operation of the refrigerant llquefying and circulating unit, by completion of the electric circuit as above described, will be interrupted by the effect of the thermal system including bulb 42, conduit 4I and bellows 54 on the control switch 40 after the temperature of the evaporator 25 and consequently the temperature of compartment 32, has been reduced to the desired or predetermined low limit. As above pointed out the mercury tube switch on the control device 40 is in the position shown in Fig. 2 of the drawings during normal operation of the system or while the thermal system comprising the bulb 45, conduit 44 and bellows is ineffective for modifying the action of the control switch 40. Consequently the electrical circuit to the solenoid H0 is made by contacts 92 and 93 through the mercury tube switch from the one side of the power line and through the solenoid IIII and is broken at the clock or chronometric device 40 while th's device is in its position to complete the circuit through the control device to the motor 21 of the refrigerating system. However, as soon as and when the timing mechanism of the device 43 rotates the finger H9 in a clockwise direction beyond the end I32 of the ring I28 and out of engagement therewith the ring contact I21 on finger II9 will register with or contact the member I35. Engagement of contact I21 with the member I35 during the rotation of finger II9 by the clock mechanism thereby completes the electric circuit from the one side, wire I, of the power line through wire I42, wire 96, contacts 92 and 93 on the mercury tube switch, wire 91 and wire I43 to the solenoid H0 and from this solenoid H0 through wire I49, terminal I36, member I35, contact I21, finger II9, collar I22, terminal I23, wire I40 to the opposite side, wire I41, of the power line. The solenoid H0 is thus energized and this energization of the solenoid directs and lifts the plunger or enlarged portion I09, to which the valve I is secured, upwardly. Lifting of the valve I05 from its seat in this manner permits hot refrigerant in the high pressure side of the refrigerating system, or in the conduit 2I of the condenser, to flow into passage I03, in the casing I06 of the device 41, through the conduit 49, and thence into the low pressure side of the refrigerating system or into the evaporator 25. This introduction of hot refrigerant from the condenser 2|, into the cooling unit or evaporator 25, will of course, immediately raise the temperature of the evaporator and will cause frost or ice accumulated on the walls thereof to melt there-- from.

Since defrosting of the evaporator is controlled by the clock or chronometric device 40 and this defrosting occurs preferably once a day or every 24 hours very little frost or ice will have accumulated on the walls of the evaporator 25 over this'period of time. Therefore it is apparent that opening of valve I05 over a short period of time only, or the flow of a small amount of hot refrigerant from the condenser to the evaporator will cause the thin coat of frost or ice accumulated on the evaporator, over a period of time of 24 hours to be effectively removed therefrom. It is to be understood that the thermostats 42 and 45 are so located and arranged that there is a sumcient lapse of time before the heat of the refrigerant admitted to the evaporator, to effect defrosting thereof, can be conducted or. transmitted to the thermostats 42 and 45. In this manner the defrosting cycle of refrigerating apparatus or system is not prevented by the thermostats 42 and 45 and these thermostats will not affect the control switch 40 until after the temperature of the evaporator 25 or the temperature within compartment 32 has materially risen. In

other words the time lag between conduction or transmission of the heat of the refrigerant admitted to the evaporator and its effect upon the thermostats is suflicient to insure that this heat will melt frost from the walls of the evaporator. 5 However, if and when either thermostat 42 or 45 is affected by the heat of defrosting, to actuate or effect the control switch 40, defrosting of the evaporator 25 will have already occurred.

It is therefore immaterial if thermostat 45 should l0 actuate the mercury tube switch on the control 40 into a position opposite that shown in Fig. 2 of the drawings to break the circuit through contacts 92 and 93 thereof and to the solenoid H0 or if thermostat 42 should actuate the contact 52 of the control 40 into engagement with the contact 54 to cause operation of the refrigerant iiquefying and circulating unit. The reason such operation of the control device 40 is immaterial to my invention and likewise to the successful operation of my refrigerating system is because of the fact that defrosting of the evaporator takes place quickly and previous to the actuation of the control 40 by the thermostats 42 and 45. The control switch 40 should on the other hand be in a position to cause operation of the refrigerant liquefying and circulating unit immediately after defrosting of the evaporator has occurred, in order to again reduce the temperature of the evaporator 25 and the compartment 32 to the desired low temperature limit, and the effect of the heat of defrosting on the thermostats 42 and 45 aids this requirement.

The essential and highly important feature of my improved refrigerating apparatus is to insure that defrosting of the evaporator thereof cannot and will not occur at a time when a substance to be congealed or frozen is placed in the evaporator or while quick freezing of such substance is in progress. Accordingly when a warm substance contained in a tray is placed in the freezing zone or sleeve 30 of the evaporator 25 the heat of this substance is immediately or quickly conducted to the thermostat 45, due to the thermal relation of thermostat with sleeve 30, and this 45 heat causes the volatile fluid within the thermostat 45, conduit 44 and bellows 8| to expand. Expansion of the fluid in this thermal system causes expansion of bellows III and this bellows therefore moves into engagement with or into the path of the lever 55 of the control device 40 thus actuating lever 55 to cause contact 62 to engage contact 54 of the control device and adds more resistance to the downward movement of the lever 55. When the contacts 62 and 54 are already 55 in closed position the bellows 8| will keep them in this position until after the substance in the ice tray has been frozen. Closing of contacts 92 and 64 when a substance is to be quickly frozen in the evaporator completes the electric circuit to the motor 21 irrespective of the position of the finger I I9 on the clock or chronometric device 43. By operating the motor 21 and consequently compressor 20 continuously over long periods of time until after the ice tray has been cooled, freezing 65 of substance contined in the tray is accelerated.

Movement of the bellows 3| to actuate the switch contact 52 into engagement with its corresponding contact 54 or to add resistance to the downward movement of lever 55 also actuates the mercury tube switch into a position to break or open the circuit through contacts 92 and 93 of the mercury tube switch and to complete or make a circuit through contacts 94 and 95 thereof. Breaking of the circuit in this manner at contacts 92 and 93 interrupts the power circuit to the solenoid IIII irrespective of the position of the finger H9 on the clock or chronometric device 48. The simultaneous making of the circuit at contacts 94 and 95 completes a circuit around the clock or chronometric device 48 so that the position of finger II! thereon relative to the ring I28 or member I35 cannot interfere with the operation of the motor 2'! of the refrigerating system during the modified operation of the system to quickly freeze the substance in the evaporator. Contacts 94 and 95 complete the electric circuit from wire I45 to the motor 21 and through wire I44, contacts 62 and 64, to wire I 4| on the opposite side of the power line. The portion of the electrical circuit including wires I46 and I48, contacts I26 and I21, finger II! and ring I28 controlled by the clock 48 is rendered ineffective for causing energization of the solenoid I In and consequently defrosting of the evaporator cannot occur since the circuit from the solenoid III] to the one side of the power line is broken at contacts 92 and 93 even if finger H9 should be rotated into communication with the member I35 during operation of the system under the control of the control device 40 while thermostat 45 is effecting the control 40. Movement or rotation of finger II9, on device 48, out of communication with ring I 28 and into communication with the member I35 will not open or break the circuit to stop operation of motor 21, during operation of the system under the control of the control device 40 while thermostat 45 is effecting the same, due to the fact that the circuit through motor 21 is made by contacts 94 and 95 of the mercury tube switch and the wires leading from these contacts to the power line.

After the substance in the ice tray II has been congealed or frozen by the modified operation of the refrigerating system, fluid within the thermostat 45, conduit 44 and bellows II will contract and the springs 82 will pull bellows ll downward out of the path of the arm 55 on the control device 40. The system and consequently the control 40 is then rendered operative to continue operation under the influence of thermostat 42 to maintain the compartment 32 of the refrigerator cabinet and consequently the evaporator of the refrigerating system between the desired predetermined normal refrigerating temperatures. Movement of bellows ll downwardly likewise again actuates the mercury tube switch, on the control device 44, into the position shown in Fig. 2 of the drawings to break the circuit at contacts 94 and 95 and to make the circuit at contacts 92 and 93. The electrical circuit is thus again completed through the mercury tube switch to the solenoid H and this circuit is again under the control of the clock or chronometric device 48. Therefore as long as the system is in operation to maintain the evaporator 25 and the compartment 32 of the refrigerator cabinet between predetermined normal refrigerating temperatures, the electrical circuit of the system is operative to cause periodic defrosting of the evaporator under the control of or in response to the timing device or chronometric means 44.

From the foregoing it is apparent that I have provided an improved refrigerating apparatus which automatically maintains the evaporator thereof and consequently the compartment in which the evaporator is located between normal predetermined temperature limits and wherein operation of the system is modified automatically to operate continuously in response to the lnser.

tion in the evaporator of a substance to be frozen. My improved refrigerating apparatus or system also includes means for causing defrosting of the evaporator at predetermined timed intervals which means is associated with the means for effecting quick freezing of substance placed in the evaporator of the refrigerating system in such a manner as to insure that defrosting of the evaporator will not and cannot occur when quick freezing of the substance by the evap- 10 orator is initiated or is in progress. It will also be apparent from the foregoing that the arrangement of the auxiliary devices and their association with one another insures that the refrigerating system will immediately be caused to operate in a manner different from the normal operation thereof when a substance is placed in the evaporator to be frozen irrespective of whether defrosting of the evaporator is taking place or whether the system is idle or operating under normal conditions.

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. Refrigerating apparatus including a refrig erating liquefying and circulating unit and an evaporator adapted to receive a substance to be congealed or frozen operatively connected with said unit, means for controlling the operation of said unit to normally maintain said evaporator between predetermined temperature limits, means responding automatically to the temperature of a substance placed in intimate thermal association with the evaporator for modifying from normal the operation of said unit to lower the temperature of the evaporator below the normal predetermined low temperature limit thereof, means operable automatically in response to a certain duration of operation of said unit for causing the temperature of said evaporator to temporarily increase above the normal predetermined high temperature limit thereof, and means rendered effective automatically by the operation of said second named means for rendering said third named means ineffective.

2. Refrigerating apparatus including a refrigerant liquefying and circulating unit and an evaporator adapted to receive a substance to be congealed or frozen operatively connected with said unit, means for controlling the operation of said unit to normally maintain said evaporator between predetermined temperature limits, means responding automatically to the temperature of a substance placed in intimate thermal association with the evaporator for modifying from normal the operation of said unit to lower the temperature of the evaporator below the normal predetermined low temperature limit thereof, chronometrically operated means for causing the temperature of said evaporator to increase temporarily above the normal predetermined high temperature limit thereof, and means rendered eflective automatically by the operation of said second named means for rendering said chronometrically operated means ineffective.

3. Refrigerating apparatus including an evaporator adapted to receive a substance to be congealed or frozen thereby and a refrigerant liquefying and circulating unit operatively connected with said evaporator, means for controlling the operation of said unit to cyclically circulate a refrigerating medium through said evaporator to normally maintain the temperature thereof between predetermined temperature limits, means responding automatically to the temperature of a substance placed in intimate thermal association with the evaporator for modifying from normal the cyclical operations of said wt to lower the temperature of said evaporator below the normal predetermined low temperature limit thereof, means operable automatically in response to a certain duration of cyclical operations of said unit for causing the temperature of said evaporator to temporarily increase above the normal predetermined high temperature limit thereof, and means rendered effective automatically by the operation of said second named means for rendering said third named means ineffective.

4. Refrigerating apparatus including an evaporator adapted to receive a substance to be congealed or frozen thereby and a refrigerant liqueiying and circulating unit operatlvely connected with said evaporator, means for controlling the operation of said unit to cyclically circulate a refrigerating medium through said evaporator to normally maintain the temperature thereof be tween predetermined temperature limits, means responding automatically to the temperature of a substance placed in intimate thermal association with the evaporator for modifying from normal the cyclical operations of said unit to lower the temperature of said evaporator below the normal. predetermined low temperature limit thereof, chronometrically operated means for causing the temperature of said evaporator to increase temporarily above the normal predetermined high temperature limit thereof, and means rendered effective automatically by the operation of said second named means for rendering said chronometrically operated means ineffective.

5. Refrigerating apparatus including a refrigerant liquefying and circulating unit and an evaporator adapted to receive a substance to be congealed or frozen operatively connected with said unit, means for controlling the operation of said unit to normally maintain said evaporator between predetermined temperature limits, means responding automatically to the temperature of a substance placed in intimate thermal association with the evaporator for modifying from normal the operation of said unit to lower the temperature of the evaporator below the normal predetermined low temperature limit thereof, means for supplying heat to said evaporator to temporarily increase its temperature above the normal predetermined high temperature limit thereof, means associated with said third named means and operable automatically in response to a certain duration of operation of said unit for rendering said third named means effective, and means rendered effective automatically by the operation of said second named means for rendering said third named means ineffective.

6. Refrigerating apparatus including a refrigerant liquefying and circulating unit and an evaporator adapted to receive a substance to be congealed or frozen operatively connected with said unit, means for controlling the operation of said unit to normally maintain said evaporator between predetermined temperature limits, means responding automatically to the temperature of a substance placed in intimate thermal association with the evaporator for modifying from normal the operation of said unit to lower the temperature of the evaporator below the normal predetermined low temperature limit thereof,

means for supplying heat to said evaporator to temporarily increase its temperature above the normal predetermined high temperature limit thereof, chronometric means associated with said third named means for rendering said third nmed means effective, and means rendered effective automatically by the operation of said second named means for rendering said third named means ineffective.

7. Refrigerating apparatus including a refriglo erant liquefying and circulating unit and an evaporator adapted to receive a substance to be congealed or frozen operatively connected with said unit, means for controlfing the operation of said unit to normally maintain said evaporator between predetermined temperature limits, means responding automatically to the temperature of a substance placed in intimate thermal association with the evaporator for modifying from normal the operation of said unit to lower the temperature of the evaporator below the normal predetermined low temperature limit thereof, means for supplying heat to said evaporator to temporarily increase its temperature above the normal predetermined high temperature limit thereof, means associated with said third named means and operable automatically in response to a certain duration of cyclical operations of said unit for rendering said third named means effective, and means rendered effective automatically by the operation of said second named means for rendering said third named means ineffective.

8. Refrigerating apparatus including a refrigerant liquefying and circulating unit and an evaporator adapted to receive a substance to be congealed or frozen operatively connected with said unit, means for controlling the operation of said unit to normally maintain said evaporator between predetermined temperature limits, means responsive automatically to the temperature of a substance placed in intimate thermal association with the evaporator for modifying from normal the operation of said unit to lower the temperature of the evaporator below the normal predetermined low temperature limit thereof, means for supplying heat to said evaporator to temporarily increase its temperature above the normal predetermined high temperature limit thereof, chronometric means associated with said third named means for rendering said third named means effective, and means rendered effective automatically by the operation of said second named means for rendering said third named means ineflective.

9. Refrigerating apparatus including a refrigerant liquefying and circulating unit and an evaporator adapted to receive a substance to be congealed or frozen operatively connected with said unit, an electrical control switch operated automatically in response to the temperature of the evaporator for controlling the operation of said unit to normally maintain said evaporator between predetermined temperature limits, means responding automatically to the temperature of a substance placed in intimate thermal association with the evaporator for modifying from normal the action of said control switch and simultaneously modifying from normal the operation of said unit to lower the temperature of the evap orator below the normal predetermined low temperature limit thereof, means for supplying heat to said evaporator to temporarily increase its temperature above the normal predetermined high temperature limit thereof, means operable automatically in response to a certain duration of operation of said unit for controlling the operation of said second named means, and a second electrical switch operable automatically in response to the operation of said first named means for rendering said third named means ineffective for controlling the operation of said second named means and for simultaneously causing operation of said unit under the influence of the modified action of the control switch.

10. Refrigerating apparatus including a refrigerant liquefying and circulating unit and an evaporator adapted to receive a substance to be congealed or frozen operatlvely connected with said unit, an electrical control switch operated automatically in response to the temperature of the evaporator for controlling the operation of said unit to normally maintain said evaporator between predetermined temperature limits, means responding automatically to the temperature of a substance placed in intimate thermal association with the evaporator for modifying from normal the action of said control switch and simultaneously modifying from normal the operation of said unit to lower the temperature of the evaporator below the normal predetermined low temperature limit thereof, means for supplying heat to said evaporator to temporarily increase its temperature above the normal predetermined high temperature limit thereof, means operable automatically in response to a certain duration of operation of said unit for controlling the operation of said second named means, and a second electrical switch operable automatically in response to the operation of said first named means for rendering said second named means ineffective.

ll. Refrigerating apparatus including a cooling element adapted to receive a substance to be congealed or frozen, a device connected with said cooling element and adapted to circulate a refrigerant medium therethrough, means for controlling the operation of said device to normally maintain said cooling element between predetermined temperature limits, means responding automatically to the temperature of a substance placed in intimate thermal association with the cooling element for modifying from normal the operation of said circulating device to lower the temperature of the cooling element below the normal predetermined low temperature limit thereof, means operable automatically in 6 response to a certain duration of operation of said circulating device for causing the temperature of said cooling element to temporarily increase above the normal predetermined high temperature limit thereof, and means rendered 10 effective automatically by the operation of said second named means for rendering said third named means ineffective.

12. A refrigerating system including an insulated cabinet having an evaporator located there- 5 in, control means for automatically controlling said system, means responsive to abnormal demands for refrigeration for automatically varying the operation of the system, a defrosting device for defrosting said evaporator, and means rendered effective automatically by the operation of said varying means for rendering said defrosting device ineffective.

13. A refrigerating system including an insulated cabinet having an evaporator located therein, control means for automatically controlling said system, means responsive to abnormal demands for refrigeration for automatically varying the operation of the system, a fully automatic defrosting device for defrosting said evaporator, and means rendered effective automatically by the operation of said varying means for rendering said defrosting device ineffective.

14. A refrigerating system including an insulated cabinet having an evaporator located therein, control means for automatic control of said system, means responsive to abnormal demands for refrigeration for varying the operation of the system, a fully automatic defrosting device for automatically at intervals defrosting said evaporator, and means for rendering said defrosting device ineffective whenever said varying means responds to abnormal refrigeration demands.

LLOYD M. KEIGHLEY.

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