US1424826A - Axfbed d - Google Patents

Description

A. D. KARR AND K. D. PERKINS.. coNTRoL Foa Humm-:RATING MACHINES.

APPLICATION FILED MAR. 2. 1920.

Patented Aug. 8, 1922.

l UNITED Slli'liljlm miia'iieiri ortica.

ALFRED n. kann, or NEWARK, NEW JERSEY, AND KAEL D. PERKINS, or NEW YORK, N. Y., AssIGNoRs To AUDIEEREN REERIGERATING MACHINE oo., or NEW YORK,V

N. Y., A. CORPORATION F NEW JERSEY.

Specification of Letters Patent.

CONTROL FOAR REFRIGERATING MACHINES,

Patented Aug. 8, 1922.

Application filed March 2, 1920. Serial 110.862,75.

VState ot New York, have inventedcertain new andusetul Improvements in Controls tor lefrigerating Machines; and we do hereby declare the 'following to be a tull, clear, and exact description 'ot the invention, such `vill enable others skilled in the art toivhich it appertains to make and use the saine.

The present invention relates to a system ot theiniostatic control tor re-'frigerating machines. particularly ot' the Auditfren type in which the apparatus comprises a pair oit rotary communicating vessels, sometimes called a dumb-bell trom their resemblance thereto. ln one ot the vessels or bells which y is usually knoivn as the compressor' bell, the

retrigerating Atluid is compressed, and in the other bell which is known as the expansion loell the vfluid is expanded to 'absorb heat trom the surroiuiding; medium, which may be the liquid that is to be cooled, or some other liquid, Asuch as brine, that in turn is to be used' 'for cooling the desired liquid. The vessel. or bell in which the compression ot the retrigerating` fluid takes place is partly immersed in the cooling liquid to absorb the heat evolved during compression. there being' a continual flou' of such liquid through the containingI tank which is usually called the ccondenser rank ot the apparatus. The cooling liquid is discharged trom the condenser tank through an overiioiv pipe having` its inlet end located in the condenser tank at a height sutiicient to maintain level in this tank which will keep the compression bell partially submerged.

The supply oi cooling` liquid to the condenser tank is regulated by means ot a small tank, usually called a feed tank. a float` and a valve controlled by the position ot the float. rllhe .teed tank is located adjacent the condenser tank and is provided with an opening leading to a stand pipe which evtendsv into the condenser tank and terminates near the compressor bell but above the normal level ot the liquid in the condenser tank. The portion of the stand pipe Within the condenser tank is provided with an auxiliary oi bleeder opening of small diameter, located at or below the normal level of the cooling liquid in the tank.

lVhen the compressorbell is rotated a Wave of liquid will tend to follovv it, and some oit this liquidivill spill into the stand pipe and flow into the feed tank. The rising liquid in the feed tank Will raise the float., thereby opening the valve which controls the supply ot cooling liquid. It the bells stop rotating` the supply ot liquid to the stand pipe will cease, and the feed tank will be slowly emptied through the stand pipe and bleeder into the condenser tank. The ball of the tloat valve Will then drop to cut off the supply ot cooling liquid.

lt has heretofore been proposed to use a thermostat in the cooling` or brine tank to control the rotary vessels or bells according to the thermal condition of the liquid in this tank, but such a thermostat is not sufficient to provide t'or all contingencies of operation, and particularly those due to eX- cessive temperature in the condenser tank, which temperature may result in injury to the vessel located therein unless rotation of the latter is stopped to stop compression of the reirigeratingv iluid in this vessel.

The above defect in apparatus of the character above 'described cannot 'be remedied with certainty by the provision of a thermostat in the condenser tank, since the thermostat maybe immersed in the liquid therein, and yet the liquid may not be heated because its level may have fallen out ot' contact ivith the compressor bell. It this condition exists the thermostat `will not be affected, with the result that the controllingl mechanism to which it may be connected` will not stop the rotation ot the bells. It is accordingly an object ot the present invention to improve the urrangenientot the 'feed tank With relation-to the condenser tank so as to permit a thermostat to be used effectively in the condenser tank as Welll as in the re'lrigerating tank for controlling the rotary parts o'f the apparatus. t is a turther object ot the invention to arrange the thermostatic system so that these instruments will so control the motor which drives the rotary parts of the apparatus as to provide for the various contingencies of operation occurring in practice.

ln accordance with the present invention, the stand pipe leading to the feed tank is provided with a small orifice which communicates with the condenser tank at substantially the normal lever of liquid therein.

as determined by the overflow pipe. With this arrangement, if the supply of cooling liquid fails while the bells continue to rotate, liquid supplied to the feed tank through the stand pipe will drain back into the condenser tank. thus maintaining substantially normal liquid level therein, Since -the compression bell remains partly submerged, its heat will be imparted to the cooling liquid and if the supply of such liquid is not continuous, the liquid will ultimately become so warm thatthe thermostat in the condenser tank will be affected and will act through suitable controlling devices to stop the rotation of the bells. The thermostats exercise in general, a joint control, but the one in the cooling or refrigerating tank is to an extent under the domination of the one in the condenser tank, so that the former cannot initiate any movement of the rotary bells unless the latter thermostat is in its normal position, due to a sufficiently low temperature in the condenser tank.

The arrangement of the feed tank, and the manner in which the control of the apparatus is secured by the thermostats, as well other objects and advantages of the invention, will appear more. clearly from a description of certain preferred embodiments thereof as illustrated in the accompanying drawings in which F l is a view of the refrigerating machine in side elevation with the thermostatic control system shown diagraininaticallyg l Fig, 2 is a sectional end elevation through 'the condenser and feed tanks; 'and Fig'. 3 shows a modified arrangement of the thermostats.

In the drawings 10 represents the condenser tank and l1 the cooling or refrigera'ting tank. The rotary parts of the apparatus or dumb-bell comprise a spherical compression bell l2 and a cylindrical expansion bell 13. These bells are in communication through a pipe 141- which also serves as a shaft for supporting the bells in suitable bearings at the top of the tanks. The bells are driven by means of a pulley '15 over which passes a. belt 16 driven by a motor 17 which is provided with a control system which will be hereinafter described. Since 'the bells may be of any preferred construction charcateristic of apparatus of this type, and since the particular construction forms no part of the present invention, they have been shown on y diagrammatically. The compression bell 12 is covered by a hood 18 placed on top of the compression tank, and a similar hood 19 placed on top of the refrigerating tank covers the bell 13. c

Adjacent the condenser tank and under the near the top thereof is a small feed tank 20. Liquid is supplied to this feed tank by a stand-pipe 21 connected at one end to the bottom of the feed tank and having its other end near the compression bell and in a position to collect some of the liquid carried up by the rotation of this bell. YWithin the feed tank is a float 23 which controls a valve 22. The valve 22 is inserted in a pipe 24 through which cooling liquid is supplied to the condenser tank. The stand pipe within the condenser tank is pro-vided with a bleeder orifice 25 of relatively small aperture which is located at substantially the normal level of the cooling liquid of this tank as determined by an overflow pipe 26 as shown in Fig. l, through which the cooling liquid is discharged from the tank.

The thermostatic control system shown in Fig. 1 comprises a thermostat 30 of any preferred construction having its heat responsive element located in the condenser tank 10 at some distance below the normal level of liquid therein. The thermal element is adapted to move a contact needle 31 between two iiXed contact points 32 and 33. A similar thermostat is arranged in the refrigerating tank 11 and its Contact needle 35 moves between contacts 36 and 37. In each of these thermostat-s the needle is moved in a clockwise direction upon increase of teinperature, so that in the case of thermostat 30 in the cooling tank the needle 31 will under conditions of low temperature be in engagement with contact 32, which is connected by a conductor 38 tothe needle 35 of the thermostat 3ft. Contact 86 of thermostat 3lan'd contact 33 of thermostat 30 are connected by conductors 39 and et() to one terminal of the secondary winding of a transformer il of the controller fo-r motor 17. The other terminal of this coil is connected by a conductor 42 to the contact 37 of thermostat 341-. The primary winding of the transformer 41 is connected by conductors 13 and lil to the outer contacts of a main switch 45 connected to a three-phase power line. .he middle co-ntact of this switch is connected by means of a conductor 16, directly to the motor 17. The other motor conductors 4T and '-18 are connected to contacts i.t9 and 5() of an automa-tic electromagnetic switch of which the actuating coil is shown at 51,'but the switch arms are not shown, it being understood that they are adapted when the coil 51 is energized to connect contacts 49 and 50 with contacts 52 and 53 respectively, which latter contacts are connected by conductors 54 and 55 to conductors 43 and 44 respectively, and thereby to the supply line, through switch 45.

For energizing the coil 51 of the automatic switch, a controlling switch of substantally similar, but smaller construction is provided. One terminal of the energizing coil 56 of this switch is connected to conductor 39 leading to the secondary of the transformer, and the other termin-al is connected by a conductor 57 to the needle 31 of thermostat 30, The coil 51 of the automatic switch is connected between conductor and a contact 58 of the controlling switch. The other contact 59 `of this latter switch is connected to conductor 42. The corresponding upper contacts and 61 of the controlling switch are connected respectively to conductors 54 and 57.

In considering the operation of the app-aratus described above, it will be assumed thatthe refrigerating bells are at rest and that the temperature in the condenser tank 10 sufficiently low to cause the needle 31 of thermostat 30 to engage contact 32. In order to start the motor, the main switch 45 is closed to establish a circuit through the primary winding' of the transformer 41. The current from the secondary winding of this transformer will then pass through the yenergizing coil 56 of the controlling switch,

conductor 57, needle 31 of thermostat 30, contact 32conductor 38, needle 35 of the thermostat 34, which will be in engagement withcontact 37 because the liquid in the refrigerating tank` is assumed to be comparatively warm, thence over conductor 42 to the other terminal of the secondary coil. Energiz'ation of the coil 56 of the controlling switch will establish the circuit of the coil 51 of the motor switch over conductors 43, 54, terminal 60 of the controlling switch, the switch blade thereof, terminal 58 and conductor connecting this `terminal vto the coil 51, conductors 55 and 44 back to the main switch 45. Enerz'gizationY of the coil 51 of the motor switch will cause the blades of this switch to put contacts 49 and 50 in circuit with contacts 52 and 53 respectively, so that the motor circuit is established over conductors 44, 55 and 48 leading from one blade of the main switch, and over conductors 43, 54 and 47 leading from the third blade of this switch. The motor will thus be connected directly to the source of electrical supply, and will start into operation to rotate the dumb-bell.

As the dumb-bell rotates in the direction indicated by the arrow in Fig. 2, the member thereof located inthe condenser tank will cause a wave of liquid to follow the rotating bell, and this liquid will spill into the open end of the stand pipe 21 and flow into the feeder tank 20, ultimately lifting the float 23 to open the valve 22 controlling the supply of cooling liquid to the condenser tank. This liquid will flow into the condenser tank and will be discharged through the overflow pipe 26, keeping the rotating bell partly submerged in relatively cool liquid. The apparatus will operate in the manner characteristic of apparatus of this type, and the expansion of the refrigerating fluid in the bell or vessel 13 will begin to lower the temperature of the liquid in the refrigerating tank 11.

It was assumed that at the start of the operation the temperature in refriger-ating tank was high enough to cause the needle 35 of the thermostat 34 to engage contact 37, but as the temperature in this tank decreases, the needle will move away from this contact, but this will not open the motor controlling circuit because when the coil 56 of the controlling switch was energized, it established a holding circuit for itself from the secondary ofthe transformer, through coil 56, contact 61, the blade of the switch which connects this contact to contact 59 and thence over the conductor 42 back to the secondary. T he controlling switch thus being held in a closed position will keep the coil 51 of the motor switch energized and the motor will continue in operation. If the temperature in the. refrigerating tank falls so low that thel arm' 35 of the thermostat 34 in this tank engages contact 36, a short circuit will be established around the coil 56 of the controlling switch. This short circuit includes conductor 39, contact 36, thermostat needle 35, conductor 38, contact 32, thermostat needle 31 and conductor 57. When coil 56 is thus short circuited, the switch associated therewith .is opened to break t-he circuit of coil 51 and thus open the motor circuit. So long as the thermostat needle 35 is in engagement with contact 36, the motor will be cut out of operation, and even if the temperature in the refrigerating tank 11 increases enough to cause the needle 35 to move away from contact 36, the motor` will not be started into operation because the circuit of the coil 56 of the controlling switch cannot be established until the needle 35 of thermostat 34 engages contact 37, as has been previously explained in tracing the energizing circuit `of coil 56.

If the dumb-bell is rotating and there is a suilicient flow of cooling liquid through condenser tank 10, the needle 31 of the thermostat in this tank will remain in engagement with contact 32, but if for any reason the flow of cooling liquid decreases or fails entirely the liquid in the condenser tank will gradually be warmed from the effect of the bell in this tank, and finally needle 31 will move away from contact'32 and engage contact 33. In lorder that too long a time should not elapse between the disengagement from les frzontact 32 engagement with contact 33, the gap between these lcontacts should be relatively small. lll/*hen the needle 2l engages contact 33 a short circuit will be established about the coil 56 olf the controlling switch. T his short circuit will include the conductor 57, .the needle 3l of thermostat 30, the contact 63, the conductor 40 and the Conductor 2&9 to the other side of coil 56. This short vcircuit will he established irrespective of the condition ol thermostat 34: in the refrigerating tank, and will result in the de-energization of coil 56 and the opening of the switch controlled thereby, which in turn, will open the circuit of the coil 5l of the motor switch lo open the circuit of the motor and prevent farther rotation or" the dumb-bell until the tlon of cooling liquid in the condenser tank has been established and the temperature of the liquid in this tank sufficiently reduced to bring the needle 3l of the thermostat into engagement with contact 32 so that the motor can again be started into operation through the controlling apparatus, by permitting the coil 56 of the controlling switch to be energized. v

ln the arrangement described above, the thermostat in the retrigerating tank is to an extent under the control of the thermostat in the condenser tank inasmuch as the former thermostat can stop orstart the motor only ii the latter thermostat is in the condition corresponding` toa normal low temperature in the condenser' tank, since a portion oi the circuit leading from the needle of the thermostat in the rerigera-ting tank includes a contact and the needle of the therinostat in the condenser tank. In Figure 3 lthere is shown an arrangement of thermostatic controlwhereby either thermostat may stop the motor regardless of the position of the needle of the other thermostat, but neither thermostat can start the motor unless the needle ot the other thermostat is in normal circuit closing position. ln the arrangement shown in this ligure. the conductors 39', 4t2 and 57 correspond to the conductors 39, 42 and 57 of Fig. l and are connected to controlling apparatus as in the latter ligure.

The thermostat 30 in the condensertank has two separate needles 65 and 66 insulated -trom each other. Needle 65 is adapted to engage a contact 67 when the normal low temperature of the liquid in the condenser tank exists, and needle 66 is adapted to engage a contact68 upon a predetermined increase of temperature of the liquid in the condenser tank. Contact 67 is connected by a conductor 69 to the conductor 42 leading to the controlling apparatus, and contact 68 is connected by a conductor 70 to the conductor 39 leading to the same apparatus. The needle 66 is connected by conductor 71 to the conductor 57 leading to the controlisa-ieee apparatus. Thethermostat 34 in the retrigerating tank is provided with a needle 72 and contacts 73 and 74e. The needle72 is connected to conductor 57 by a conductor Contact 73y is connected to conductor 39 by a co Aductor 76 and contact 74 is connected to the needle 65 of thermostat 30 by a conductor 77. y

, Vi ith the thermostatsconnected as above described, the circuit for the coil 56 of the controlling switchincludes conductors l2 and 69, contact 67, needle 65, conductor 77, contact 74, needle 72, conductor and conductor 57.

Contact 67 as it will be it a sutiiciently low temperature exists in the condenserr tank, and, it the needle 7 is in engagement with the contact 741 as it will be under normal conditions due to a relatively high temperature olf the liquid in thereifrigerating tank. If the temperature in theire'frigerating tank falls suliiciently to cause the needle 72 to leaye contact 74 and 'finally engagev contaat73, a short circuit'will be vestablished about the coil 56 of the controlling switch as follows: conductors 57 and 75, needle 72. contact 73 and conductors 76 and 39. This short circuit will cause the deenergization oi coil 56, ,which in turn will deenergize the coil of the motor Vswitch and stop the apparatus. It the temperature in the condenser tank rises, due to an insufficient supply ofl cooling liquid or any other cause,

sulhciently to cause the needle 65 to disencontact 67 and the needle 66 to engage I The/circuit can be completedv only ii the needle 65 1s in engagement with its contact 68, a short circuit will likewise be established about the coil 56 of the controlling switch as Jfollows: conductors 57 and 7l., needle 66, contacts 68 and conductors 70 and 39. This will result in stopping the motor to prevent damage to the apparatus.

lt the motor has been stopped, either on account of a suticiently'low temperature in the retrigeratingtank, or on account of an abnormal increase or' temperature in the condenser tank, the retrigerating apparatus no longer functions and the liquid in the retrigerating tank will gradually become "Warm, and may finally cause the needle 72 to engage contact 741-, but since the circuit leading from this contact through conductor 77 includes the needle 65 ot the thermostat in the condenser tank, the motor cannot be started unless needleG -is in engagement with contact 67 to complete. the circuit through conductors 69 and-4t2 to the. controlling apparatus. This :arrangement insures that the thermostat in the refrigerating tank will not start the apparatus into operation unless a sufficiently low temperature exists in the condenser tank to avoid any overheating of the rotary bell located therein. Viewed in another way, if the motor has been stopped by an abnormal temperature in the condenser tank, and this temperaturev is lowered by adding cool liquid, .or in any other way, .to` cause needle to engage contact GT, the motor Will not be started intov operation until. the temperature in the refrigerating tank has risen suiiiciently to cause the needle 72 to engage its Contact 74 to permit the energizing circuit of the coil of the controlling switch to be established.

it Will thus be seen that bothin the case of the arrangement shown in Fig. l and in the case of the modified arrangement shown in F ig. 3, the control is such as to take care of all contingencies of operation that may occur in practice, and at the same time keep the refrigerating apparatus inactive during such times as a Asufficiently low temperature exists in the refrigerating tank, thereby conserving power and preventing unnecessary Wear upon the apparatus. vBy virtue of the arrangement of the feed tank, the stand pipe and the bleeder in the stand pipe, the rotary bell located in the condenser tank is protected at all times by being suliiciently immersedin cooling liquid to impart heat to the latter to affect the thermostat therein. l

-driving motor, said thermostats being'elefc- It Will also be seen that the machine is automatically supplied With Water during operation and that the Acooling Water supply is cut off When the machine is idle.

y`While a three phase motor with controlling apparatus particularly adapted thereto has been shown in connection with the thermostatic control of the present invention, it Will be understood that other types of motors and other kinds of motive vpower may be used provided that they are under the control of the thermostatic system ot the present invention, and the controlling apparatus may be suitably modified to meet the demands of ,such other types ot' motors or -other sources of power.

-lVe .claimrn 1 l. 'In refrigerating apparatus provided with a condenser tank and a refrigerating tank and motor driven compression and eX- pansion members mounted in the tanks, the combination of a thermostat in each tank, and means under the joint control o'f said thermostats for controlling the motor for .driving the said members.

2. In refrigerating apparatus provided withmotor driven compression and expansion members rotatably mounted in a` condenser tank anda refrigerating tank respectively, the combination of a thermostat in thecondenser tank. and a thermostat in the refrigerating tank, and means associated with the thermostats for controlling thev f driving motor, said thermostats beingA electrically connected to each other and to the controlling means sothat the thermostat in.

the refrigerating tank vcan control said .means onlyy when the thermostati-n the condenser tank is in normal circuit closing position due to a predetermined temperature of the liquid in said tank.

3.. ln retrigerating apparatus provided `vith motor driven compression and expansionv members rotatably mounted in a condenser' tank and a retrigerating tank Arespectively, the combinationot a thermostat in the condenser tank and a thermostat in the refrigerating tank, and means associated with the thermostats for controlling the driving motor, said thermostats being electrically connected to each other and to the controlling means so that the thermostat in the condenser tank Will act on said controlling means to stop the motor When'a predetermined temperature exists in the condenser tank irrespective rofthe condition of the thermostat in the refrigerating tank.L i

4l. In refrigerating apparatus provided with motor driven compressionv and expansion members rotatably mounted in a Voo ndenser tank anda retrigerating tank respectively, the combination of a thermostat intheJ condensertank and a thermostat in the refrigerating tank, and means associated with the thermostats for controlling the trically connected to each other and to the controlling means, so that the thermostat in ling means, provided the thermostat inthe condenser rtank is in condition to cause the controlling device to keep the motor in operation. I y i 5. In retrigerating apparatus `provided with motor driven compression and expansion'niembers rotatably mounted i-n a. condenser tank and a retrigerating'tank respectively, the combination of a thermostat in the condenser tank and a thermostat in the refrigerating tank, and means associated with the thermostats for controlling the driving motor, said thermostats being electrically connected to each other and to the controlling means, so that either thermostat .may stop the motor regardless of the Aother thermostat and oneot the thermostats may start the motor only if the other thermostat is in position to start the motor. p

6. In rerigerating apparatus provided with motor driven compression and expansionmembers rotatably mounted ina condenser tank and a refrigerating tank respectively, the combination of a thermostat III stat in the refrigerating tank so that the needle ot the last named thermostat exercises control over the motorl controlling means only if the needle of the thermostat in the condenser tank is on the contact that isconnected to the needle of the thermostat in the retrigerating tank.

7. In refrigerating apparatus provided With motor driven compression and expansion members rotatably mounted in a condenser tank and a refrigerating tank respectively, thermostats in that condenser tank and the retrigerati'ng tank, means under the joint control ot said thermostats orcontrolling the motorvtordriving the rotary members, and means controlled by the rotation of the compression member tor supplying cooling liquid to the condenser tank.

8. In refrigerating apparatus, the combination of motor driven compression and eX- pansion members rotatably mounted in a condenser tank and a retrigerating tank respectively, thermostats inthe condenser tank and the refrigerating tank, means under the joint control of said thermostats for controlling the motor for driving the rotary members, said condenser tank having valve controlled feed mechanism for cooling liquid and an overflow pipe, and means controlled by the rotation of 'the compression member -for operating the valve to admit cooling liquid to the c ondenser tank. v

9'. In refrigerating apparatus, including a condenser tank and a refrigerating tank, and motor driven compression and expansion members mounted in the respective tanks, means for controlling the lovv oit cooling liquid through the condenser tank whereby to regulate ythe temperature therein, means controlled by the rotation of the compression memberfor operating said means, thermostats in the condenser tank and the refrigerating tank, and means under the jointcontrol of the thermostats for controlling the motor Yfor driving the rotary members.

v10. In retrigerating apparatus, including a condenser tank and a refrigerating tank,

yand motor driven compression and expansion members mounted in the respective tanks, means for controlling the flow of cool- ,ingliquid through the condenser tank Whereby to regulate the temperature therein,

i means controlled bythe rotation of the compression member for operating said means, a thermostat in the condenser tank, and means controlled by the thermostat for opverating.the last named means. 11, In arefrigerating apparatus, including aocondenser tank and a refrigerating l tank,. and. motor driven compression and eX- ,pansion members mounted in the respective '.,tanks ymeans for -controlling the iiovv of cooling liquid through the condenser tank whereby to regulate the temperature therein,

tation ot the compression member, valve controlled means for Supplying cooling liquid to the condenser, and a loat in the feed tank tor operating said valve, the standpipe having a bleed port to permit liquid vsupplied to the 'feed tank through 'the standpipe to flow back into the condenser tank.

12. In refrigerating apparatus including a condenser tank and an intermittently driven compression member mounted to rotate in the tank, means controlled by the temperature of the said tank for controlling the rotation. of the said compression mem ber, and means controlled by the rotation of the said'member for supplying coolir'ig liquid to the tank whereby to reduce the temperature therein. i

In refrigerating apparatus including a condenser tank and an intermittently driven compression member mounted to rotate'in the tank, means controlled by the temperature of the said tank for controlling the rotation of the said compression member, and means controlled by the rotation of the "said member tor supplying coolingl liquid ltol the tank whereby to reduce the ytemperaturel tank ivhereby to reduce the temperature therein, said means comprising a feed pipe for the cooling liquid, a yfloat operated valve for controlling. the flow through thepipe, a `feed tank in which the `loat'is'arranged', and a standpipe inthe condenser tank through rwhich liquid is supplied'by the'rotation ofv the compression member to the feed tank,

said pipe having a bleed port through Which the liquid supplied to the Vfeed tank through the standpipe may loiv'back into the' 'conl denser tank.

l5. In r'etrigerating apparatus, 'the combinat-ion with the condenser tank'and thel retrigerating tank, andthe compression and expansion membersrotating in the res ective tanks, means in each tank 'controlle' by the temperature therein,vfor controlling. the

rotation ofthe said members. 16, A,In refrigerating apparatus, the combinatio-n withthe condenser tank andthe re- 'rigerating tank, and the .COmpresfsio'n'iandl expansion members rotating in the respective tanks, means in each tank Controlled by the temperature therein, for controlling the rotation of the said members, the means in the refrigerating tank being arranged to eontroi the rotation oi" the said members only when the temperature in the condenser tank is below a selected point.

` 1T. In retrigerating apparatus, the Combination with the condenser tank and the retrigerating tank, and the compression and expansion members rotating in the respective tanks, means in each tank controlled by the temperature therein, for controlling the rotation of the said members, and means controlled by the rotation of the said members for supplying cooling liquid to the condenser tank.

18. In refrigerating apparatus provided With a condenser tank and a refrigerating tank, and a motor driven Compression member mounted in the condenser tank, the oombination of a thermostat in each tank, vand means under the joint control of said thermostats for controlling the motor for driving said member.

ln testimony whereof We aiiix our signatures.

ALFRED D. KARR. KARL D. PERKINS.

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