US2323212A - Refrigeration - Google Patents

Description

Jun 29, 19 3- E. A. IFE'NANDER REFRIGERATION Filed March 4. 1938 Y INVENTOR 54M A M ak AM I ATTORNEY.

Patented June 29, 1943 REFRIGERATION Edmund A. Fenander, Yonkers, N. Y, assignor a cor to Serve], Inc., New York, N. Y.,

of Delaware poration Application- March 4, 1938, Serial No. 193,843

- cylinder l through conduit [8 and the enriched 3 Claims.

My invention relates to refrigeration, and hasfor its object to provide an improvedsystem for transferring heat so that cooling may be eflectivelyproduced at a place above a source of refrigeration.

The above and other objects and advantages of the invention will be better understood from the following description and accompanying drawing forming a part of this specification, and of which the single figure more or less diagrammatically illustrates a heat transfer system embodying the invention.

Referring to the drawing, the invention is shown in connection with a cooling element or evaporator ll) of a refrigeration system of a uniform pressure type and like that described in application Serial No. 107,852 of Albert R. Thomas, filed October. 27, 1936, and which has matured into Patent No. 2,207,838. It should be understood, however, that the invention is not limited to the specific refrigeration system described in the aforementioned Thomas application. For purposes of description, however, it may be considered that the disclosure of the aforementioned application is incorporated in this application.

The cooling element or evaporator l0 shown in the drawing constitutes a source of refrigeration and comprises an outer shell II which is embedded in insulation l2. Liquid refrigerant, such as ammonia, enters the upper part of the cooling element through a, conduit It. An inert gas, such as hydrogen, enters the upper part of the cooling element from the .upper end of a cylinder I5 disposed within the shell H. Liquid refrigerant evaporates and difl'uses into inert gas within 'the cooling element to produce a refrigerating effect.- This refrigerating effect is utilized to cool and liquefy a volatile fluid flowing through a coil I6 which is arranged about cylinder l5 and over which the liquid refrigerant flows.

The operation of the entire refrigeration system with which cooling element I0 is associated is set forth at length in the aforementioned Thomas application and will be here briefly described. If desired, reference may be had to the aforementioned application for a more detailed description of operation.

Briefly,-"the resulting gas mixture of refrigerant and inert gas flows from cooling element In through'a conduit H to an absorber in which the refrigerant is absorbed into a liquid absorbent, such as water. The inert gas is returned to absorption liquid is conducted to a generator. By heating the generator the refrigerant is expelled from the absorption solution, liquefied in a condenser, and then returned to coolingelement ll through conduit I to complete the refrigerating cycle. The weakened absorption liquid from which refrigerant has been expelled is conducted from the generator to the absorber to absorb refrigerant vapor. In order to simplify the drawing, the absorber, generator, and condenser of the refrigeration system have not been shown, their illustration not being necessary for an understanding of this invention.

The coil it, which is arranged within and in thermal relation with cooling element III of the refrigeration system just described, form the condenser of a heat transfer system for producing cold at a place above the cooling element ID. The coil or condenser I6 is disposed below an evaporator l3 which is of the flooded type and located in a thermally insulated storage space 20. The evaporator l9 includes a receiver 2| and a looped coil 22 having a plurality of heat transfer fins 23 for increasing the heat transfer surface.

The condenser i6 and evaporator l9 form part of a closed fluid circuit which is partly filled with a suitable volatile liquid such as methyl chloride, for example, that evaporates in evaporator II and takes up heat thereby producing cold. The vapor flows from evaporator l9 through a conduit 24 into condenser l6 and the vapor is cooled and condensed by cooling element III. The condensate formed in condenser l6 flows through a conduit 25 into a vessel 26.

In accordance with this invention liquid condensate is returned to evaporator l9 by a liquid transfer device 21. The device 21 includes a ca's-'- ing 28 into which liquid flows from vessel 23 through a conduit 29. Liquid is raised from casing 28 through conduit 30 to the upper part of receiver 2! of the evaporator. A check valve 3| is provided in the lower part of conduit 30.

Within casing 28 are disposed two solenoid coils 32 and 33 separated by a non-magnetic spacing block 34. The coils 32 and 33 are hermetically sealed within the casing by a non-magnetic hollow cylinder 35 which is welded or brazed to an annular non-magnetic member 36. The member 36 is secured at its outer periphery to the inside of casing 28. The lower end of cylinder 35 is closed and flts into an opening in a lower endplate 31. The-end-plate is secured to the closed end of cylinder 35 and the lower end of the easair.

ing, as by welding or brazing, for example. with this arrangement the coils 32 and 33 are effectively sealed and out of contact with liquid which flows into the casing through conduit 29.

A piston 38 is movable within the upper part of casing 28. 'The piston is provided with a short stem 39 which is adapted to extend into the upper coil 32 when the piston is in its lower position below the connection of conduit 23 to casing 28. Piston 38 and stem 33 are formed of a suitable non-magnetic material, such as brass, for example. To the lower end of stem 38 is secured a plunger 40 which may be formed of soft iron. The piston 38 is formed with an opening 4| adapted to be closed by a valve 42 which is fixed to the outer end of a leaf-spring 43. The leafspring 43 is secured to the top surface of piston 38.

The device 21, vessel 25, and check valve 3| are preferably embedded in the insulation |2 to prevent undesirable evaporation of volatile liquid in these parts by heat transfer from surrounding Conduit 30 is also provided with insulation l2 to prevent evaporation of liquid therein.

The coils 32 and 33 are connected to a suitable source of electrical supply by conductors 44 and 45. The energization of the coils is automatically controlled by a thermal relay 48. The relay includes two fixed contact 41 and 48 which are connected by conductors 48 and 58 to terminals of the coils 32 and 33. The opposite terminals of the coils are connected to conductor 45.

The fixed contact 41 cooperates with a movable contact secured to an end of a bi-metallic strip 52 which is connected to conductor 44. About strip 52 and in thermal exchange relation therewith is provided a conductor 53 to effect quick heating of the strip when contacts 41 and 5| are closed and the electrical circuit for coil 32 is completed. The fixed contact 48 cooperates with a movable contact 54 which is secured to the end of strip 52 and insulated therefrom. The movable contact 54 is connected to conductor 44 by a conductor 55 which is out of thermal exchange relation with the strip 52.

A suitable switch 55 is connected in conductor 44. The switch 55 is only diagrammatically illustrated and may be of any well-known type adapted to be operated by a volatile fluid thermostat. The thermostat is operatively associated with switch 56 and includes a capillary tube 51 and a bulb 58 which is arranged in heat exchange relation with an auxiliary chamber formed by a short vertical tube 59. The. tube 59 is closed at its lower end and is connected at its upper end to the upper part of receiver 2|. The thermostat is charged with a volatile fluid which increases and decreases in volume with corresponding changes of temperature to effect closing and opening of switch 55.

During operation, vapor formed in evaporator l9 flows through conduit 24 into condenser l5,

in which the vapor is condensed, Condensate flows from condenser l5 into vessel 25. Assuming that contacts 48 and 54 are closed so that coil 33 is energized, the plunger 40 is attracted to plunger 40 is drawn upward into this coil and piston 38 is moved upward in the casing. With upward movement of piston 38, liquid in th upper part of the casing is forced through conduit 30 into the receiver 2| of the evaporator.

After contacts 41 and 5| have been closed, the bi-metallic strip 52 is heated by the current fiowing therethrough and also the current flowing in conductor 53 which is disposed about the strip. When bi-metallic strip 52 is heated sufiiciently. the strip flexes away from the fixed contact 41 and contact 54 engages contact 48. After coil 32 has been energized for an interval of time, thereits lower position so that piston 38 is below the connection of .conduit 29 to casing 28. Under these conditions, liquid will flow from vessel 25 through conduit 23 intothe upper part of casing 28.

When the. bi-metallic strip 52 flexes to close 4 contacts 41 and 5| and open contacts 48 and 54,

coil 33 is deenergized and an electrical circuit is completed for coil 32. With coil 32 energized,

fore, the bi-metallic strip flexes to open the circuit for this coil and close the circuit for the lower coil 33. When the electrical circuit for coil 33 is completed, plunger 48 and piston 38 are attracted by this coil to their lower positions. During such downward movement and after piston 38 has closed oi! the lower end of conduit 25, liquid below the piston causes valve 42 to open. thereby permitting liquid below the piston to flow above the piston into the upper part of the casing.

With contacts 48 and 54 closed, no current flows through bi-metallic strip 52 or conductor 53, whereby the strip 52 is permitted to cool. After sumcient cooling strip 52 flexes to open contacts 48 and 54 and close contacts 41 and 5|, whereby th electrical-circuit for coil 32 is again completed to effect another pumping stroke of piston 38. The check valve 3| is provided to maintain liquid in conduit 30 after each pumping stroke of piston 38, so that the liquid head is not lost when liquid is raised-with successive pumping strokes.

When the liquid level in receiver 2| rises so that liquid overflows into the auxiliary chamber formed by the short vertical tube 53, the bulb 58 is cooled. With cooling of bulb 58, the volatile fluid in the thermostat becomes reduced in volume whereby switch 55 is caused to open. When this occurs the device 21 is disconnected from the source of electrical supply and no liquid is returned from condenser |5 to evaporator l5. Subsequently, when the liquid level in the receiver 2| falls below the upper end of tube 53 and the volatile liquid previously introduced therein has evaporated, the temperature of bulb 58 rises. With such rise in temperature of bulb 58, the volatile fluid increases in volume whereby the thermostat becomes effective to close switch 55. This connects device 21 to the source of electrical supply whereby the thermal relay 45 operates in the manner described above to alternately energize coils 32 and 33 to move piston 38 up and down in casing 28 to raise liquid through conduit 38 into evaporator i9.

While a single embodiment of the invention has been shown and described, it will be apparent to those skilled in the art that various modifications and changes may be made without departing from the spirit and scope of the invention, as pointed out in the following claims.

What is claimed is:

1. In a heat transfer system including a closed fluid circuit partly filled with a volatile liquid and having a flooded evaporation portion and a condensation portion below said evaporation portion, an auxiliary chamber communicating with said evaporation portion whereby liquid flows into said auxiliary chamber when liquid reaches a definite level in said evaporation portion, a device for lifting liquid formed in said condensation portion to said evaporation portion at a higher level, and a control responsive to a temperature condition afiected by liquid in said auxiliary chamber for controlling said device.

2. In a heat transfer system including a closed fluid circuit partly filled with a volatile liquid and having a flooded evaporation portion and a condensation portion below said evaporation portion, an auxiliary chamber communicating with said evaporation portion whereby liquid flows into said auxiliary chamber when liquid 10 reaches a definite level in said evaporation portion, a device for lifting liquid formed in said condensation portion to said evaporation portion at a higher level, and a control responsive to liquid level in said auxiliary chamber for controlling said device.

3. In combination, an enclosure, an evaporator of the flooded type to efl'ect cooling of air in the enclosure, a heat transfer system including said evaporator and a condenser below said evaporator, a device for lifting liquid formed in said condenser to said evaporator at a higher level, and a control for operating said device, said control including a part associated with said evaporator and afiected by the liquid level in the latter and also by ambient air temperature in the vicinity of said part.

EDMUND A. FENANDER.

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