US2141882A - Refrigeration - Google Patents

Description

Dec. 27, 1938. c SHAGALQFF I $141,882

" REFRIGERATION Filed Oct. 2O, 1936 INVENTOR.

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Patented Dec. 27, 1938 UNITED STATES REFRIGERATION Harry 0. Shagalofi, Evansville, Ind., assignor to Serve], Inc., New York, N. Y., a corporation of Delaware Application October 20, 1936, Serial No. 106,501

5 Claims.

My invention relates to refrigeration, and more particularly to control of refrigeration apparatus adapted to be heated by a liquid fuel burner.

It is an object of my invention to provide an improved control for refrigeration apparatus adapted to be heated by a liquid fuel burner wherein the flow of liquid fuel to the burner is effectively controlled to regulate the quantity of heat applied to the refrigeration apparatus.

Another object of my invention is to provide an improved control for refrigeration apparatus heated by a liquid fuel burner in which the burner is operated continuously and effective to maintain an enclosed spacev at a substantially constant temperature.

Further objects and advantages of my invention will become apparent from the following de.- scription and accompanying drawing forming a part of this specification, and of which Fig. 1 is a diagrammatic illustration of refrigeration apparatus and a liquid fuel burner provided with a control device embodying my invention; and Fig. 2 is an enlarged sectional view taken on line 22 of Fig. 1 to illustrate the control device more clearly.

Referring to Fig. 1 of the drawing, I have shown my invention applied to refrigeration apparatus of a uniform pressure absorption type, generally as described in Patent No. 1,609,334

to B. C. von Platen and C. G. Munters, in which an auxiliary pressure equalizing gas is employed. The refrigeration apparatus comprises a generator 10 having a rear chamber H and a forward chamber I2 communicating with an upward ex-' tending standpipe or separator M. The generator l contains a body of absorption liquid having a suitable refrigerant in solution therein,

and, although I do not wish to be limited thereto, the absorption liquid and refrigerant may be water and ammonia, respectively.

The generator I0 is heated by a liquid fuel burner l5 which projects its flame into the downwardly extending forward end of a horizontal flue l6 which extends through the generator, A suitable liquid fuel, such as kerosene, is delivered from a supply vessel ll to the burner 15, as will be described hereinafter.

The heat applied to thegenerator causes ammonia vapor and absorption liquid in chamber l l to pass through an opening (not shown) in the lower end of a small vertical conduit l8 which constitutes a vapor-lift and conducts ammonia vapor and absorption liquid to the upper end of the stand-pipe l4. Liberated ammonia vapor entering the stand-pipe Hi from conduit l8, as well as the ammonia vapor expelled from solution in the standpipe l4 and chamber I2, flows through a conduit l9 which extends downward within an analyzer 20. The ammonia vapor passes upward through absorption liquid in the analyzer 20 and is arranged within a storage compartment 26 having thermally insulated walls 21.

An inert gas, such as hydrogen, enters the lower part of the cooling element 25 from an outer passage of a gas heat exchanger 28. The hydrogen and liquid ammonia are in counterfiow, and the ammonia evaporates and diffuses into the hydrogen with consequent absorption of heat from the surroundings of the cooling ele- .ment. The resulting mixture of ammonia and hydrogen, that is, gas rich in ammonia, fiows downward from the cooling element through a conduit 29 forming the inner 'passage'of the gas heat exchanger 28. Thelower end of the conduit 29 communicates with the lower end of an absorber 30 about which is arranged a coil 3| through which a suitable cooling medium is circulated.

Ammonia is absorbed out of the rich gas mixture into weak absorption liquid which enters the upper part of the absorber 30 through a vertically extending conduit 32. The hydrogen, which is practically insoluble and weak in ammonia, passes upward from the absorber 30 through conduit 33 and the outer passage ,of the gas heat exchanger 28 and into the cooling element 25. The gas heat exchanger 28 effectively transfers heat from the weak gas flowing toward the cooling element to the rich gas flowing to the absorber 30.

The absorption liquid flowing downward through the absorber 30 in counter-flow to the gas mixture becomes enriched in ammonia and passes through conduit 34, the outer passage of a liquid heat exchanger 35 and conduit 36 into the lower part of the analyzer 20. From the analyzer 211 the enriched absorption liquid flows through conduit 31 into chamber ll of the generator Ill.

. Liberated ammonia vapor and absorption liquid.

pass upward through the vertical conduit l8 into the upper part of the standpipe M, as explained above, to a higher level than it is in the 'absorber 30, and absorption liquid weak in ammonia flows from the chamber l2 through conduit 38,

' inner passage of the-liquid heat exchanger 35,

and conduit 32 into the upper end of the absorber 30. A portion of the conduit 32 is provided with a plurality of fins 39 to effect additional cooling of the weak absorption liquid entering the absorber 30. V a

In order to vary the total pressure in the refrigeration system just described with changes in air temperature, a vessel 40 for storing hydrogen is provided having one part thereof connected by a conduit 4| to the lower end of the condenser 22, and another part thereof connected by a conduit 42 to the gas circuit. The vessel 40 and conduits 4| and 42 provide a path of flow from the condenser 22 to the gas circuit, so that any hydrogen which passes through the condenser can flow to the gas circuit and not be trapped in the condenser. Further, should the air temperature increase so that ammonia is not liquefied in the condenser, the ammonia. vapor will flow through conduit 4| to displace hydrogen in the vessel 49 and force hydrogen through conduit 42 into the gas circuit, thereby raising the total pressure in the system so that an adequate condensing pressure results for the increased air temperature.

The burner l5 comprises two perforated cylinders 43 and 44 arranged concentrically one within the other above a burner well 45 to provide a combustion chamber 46. The top of the inner cylinder 43 is provided with a closure member 41, as shown in Fig. 1, and about the cylinder 44 is arranged a frusto-conical shell 48. When the burner is being operated, air is drawn upward through the inner cylinder 43 and the space between the outer cylinder 44 and the shell 43 and mixes with vaporized fuel to provide a combustible mixture.

In accordance with my invention, in order to controlthe quantity of heat applied to the refrigeration apparatus, the annular burner well 45 is so constructed that a depression 49 is provided which extends only about. a part of the circumference of the burner well. The portion 49, therefore, is of greater depth and extends below the remaining part of the burner well 45. To the portion 49 of the burner well is connectedthe upper end of a vertical conduit 50, the lower end of which is connected to an intermediate portion of a horizontal conduit 5| having the ends thereof connected to the lower parts of vessels 52 and 53 which are formed integrally with a casing 54. The casing 54 forms a chamber 55 into which liquid fuel is conducted througha conduit 55 from the supply vessel Liquid fuel is adapted to flow by gravity from the supply vessel IT to the chamber 55, and the conduit 56 is provided with a manually operable valve 51 for shutting off the supply of fuel to the burner when the latter is not being operated.

The flow of liquid fuel into the vessels 52 and 53 is controlled by valves 53 and 59 which are disposed at inlet openings at the bottoms of the vessels and connected by light rods 50 and 6| to floats 52-. and 53. The vessels 52 and 53 are provided with removable covers 54 and 65, respec-' tively. When liquid fuel in either one of the vessels 52 and 53 falls below a predetermined level, the float therein is lowered whereby the valve associated therewith is caused to open and admit liquid fuel into the vessel to bring the liquid fuel therein to the predetermined level. The control valves 53 and 59, therefore, function to maintain a constant level of liquid fuel in the vessels 52 and 53. Liquid fuel flows from the vessels 52 and 53 through horizontal conduit 5| and vertical conduit 59 into the annular burner well 45.

In the horizontal conduit 5| is connected a control valve 66 for controlling the flow of liquid fuel from the vessel 53 to the burner well 45. The control valve 65 comprises a casing having a partition 61 provided with an opening which is adapted to be closed by a valve 63. The valve 63 is connected by a rod 69 to an expansible bellows 10 arranged within the casing. The bellows I is connected by a tube H to a thermal bulb or element 12 which is secured to and in thermal contact with the cooling element 25 of the refrigeration apparatus. The expansible bellows l0, tube II, and bulb l2 constitute an expansible fluid thermostat adapted to maintain the storage compartment 25 at a substantiallyconstant temperature, and contain a volatile fluid which increases and decreases in volume with corresponding changes in temperature.

When the cooling element 25 tends to rise above a desired temperature, the expansible fluid thermostat causes the expansible bellows 10 to expand and move the valve 68 to its open position against the tension of spring 13 and thus permit the flow of liquid fuel from the vessel 53 to the burner well 45; and conversely, when the cooling element 25 tends to fall below the desired temperature, the expansible fluid thermostat causes the expansible bellows 10 to contract and permit the valve 68 to be urged toward its closed position by the spring'l3 to shut oil the flow of liquid fuel from the vessel 53 to the burner well 45.

The control valve 58, rod 50, and float 62 are so constructed that the predetermined level of liquid fuel maintained in the vessel 52 is slightly below that maintained in the vessel 53 by the valve 59, rod 6|, and float 63. When the burner I-is not being operated, the cooling element 25 is above the desired temperature and .the valve 68 is in its open position whereby liquid'fuel is permitted to flowv from the vessel 53 to the burner well 45. Under these conditions, the level of liquid fuel in the vertical conduit 50 and burner well 45 is at the same level as the liquid fuel in the vessel 53. This level, which is indicated atA, is such that, when the burner I5 is lighted, the flame produced by the burner will apply heat to the refrigeration apparatus at a rate suflicient to heat refrigerant to its vaporization temperature or boiling point so that refrigerant is vaporized and expelled outof solution from the absorption liquid. With the burner flame of such size that refrigerant is expelled out of solution from absorption liquid, the refrigerant apparatus operates in the manner described above to produce cold in the storage compartment 26.

When the cooling element 25 tends to fall below the desired temperature, the expansible fluid thermostat, as explained above, becomes operative to close the valve 68 whereby liquid fuel no longer flows from the vessel 53 to the burner well 45 and liquid fuel only flows to the burner well from the vessel 52. The level of liquid fuel maintained in the vessel 52 is slightly below that maintained in the vessel 53, as indicated at B, and is such that, when the burner I5 is not being operated and the valve 58 is closed, liquid fuel only flows into the depressed portion 49 of the burner well 45. The level of liquid fuel in the depressed portion 49 of the burner well 45 is such that, with the valve 68 closed and the burner l5 lighted, theflame produced by the burner will apply heat to the refrigeration apparatus at such a rate that only heat of liquid is supplied to the refrigerant and the refrigerant is heated to a temperature slightly below its vaporization temperature. Since refrigerant is not expelled out of absorption liquid under these conditions, cold is not produced in the storage compartment 25 I6 ture, the level of liquid fuel in the vessel 53 determines the normal rate at which fuel is supplied to the burner l; and that when the cooling element 25 tends to fall below the desired temperature, the level of liquid fuel in the vessel 52 determines the modified rate at which fuel .is supplied to the burner l5.

By controlling the flow of liquid fuel in the manner described above, the burner I5 may be operated continuously to maintain the enclosed space 26 at a substantially constant temperature. Further, suitable means may be'readily provided to maintain the burnerat a reduced or minimum flame rather than a maximum flame to permit defrosting of the cooling element 25 without any necessity of shutting off the burner l5. This is a distinct advantage because the generator l0 and its contents would be cooled by the surroundings if no heat were applied to the generator during a defrosting period. Subsequently, when the cooling element 25 has been defrosted, heat would have to be applied to the generator i0 and its contents fora relatively long period of time before refrigerant is heated to its vaporization temperature and expelled out of solution from the absorption liquid. By providing a control for liquid fuel whereby the application of heat to the generator is not discontinued but ismodified to apply heat to the generator at such a rate that the refrigerant is heated to a temperature slightly below its vaporization temperature, the refrigerant is heated to its vaporization temperature in a relatively short time after the termination of the defrosting period, so that the cooling element 25 is effective substantially immediately to maintain the storage compartment 26 at the desired temperature.

Although I have described and illustrated a particular embodiment of my invention, it will be apparent to those skilled in the art that modifications 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. The combination with a refrigeration system having a generator adapted to be heated, a condenser, an absorber, an evaporator, and in terconnecting conduits forming. a closed system for circulation of fluids, expulsion of refrigerant and evaporation of refrigerant to produce refrigeration, said system being so constructed and charged that the quantity of refrigeration produced is a function of the quantity of heat supplied to the generator; of a liquid fuel combustion device for heating said generator by vaporization of fuel oil to supply heat to the generator in proportion to the level of oil in the combustion device, and apparatus for feeding oil to said combustion device including a plurality of constant level devices each adapted to maintain a different liquid level in said combustion device, and means for connecting and disconnecting at least one of said constant level devices with respect to said combustion device responsive to a temperature condition affectedby said refrigeration system.

2. The combination as set forth in claim 1 in which said constant level devices include float operated valves, and said means is a thermostatic valve.

3. The combination with a refrigeration system having a generator adapted to be heated, a

condenser, an absorber an evaporator, and interconnecting conduits forming a closed system for circulation'of fluids, expulsion of refrigerant and evaporation of refrigerant to produce refrigeration, said system being so constructed and charged that the quantity of refrigeration produced is a function of the quantity. of heat supplied to the generator; of a liquid fuel combustion device for heating said generator by vaporization of fuel oil to supply heat to the generator in proportion to the level of oil in the combustion device, and apparatus for feeding oil to said combustion device including a supply conduit, at least two chambers connected to receive fuel oil from said conduit, a float operated valve for controlling flow of liquid fuel into each of said chambers to maintain substantially constant but different levels of liquid fuel in the chambers, conduits for conducting liquid fuel from said chambers to said combustion device, and a thermostatic valve for controlling flow of liquid fuel to said combustion device from the chamber in which the highest liquid level is maintained responsive to a temperature condition affected by said evaporator.

4. The combination with a refrigeration system having a generator adapted to be heated, a condenser, an absorber, an evaporator, and interconnecting conduits forming a closed system for circulation of fluids, expulsion of refrigerant and evaporation of refrigerant to produce refrigeration, said system being so constructed and charged that the quantity of refrigeration produced is a function of the quantity of heat supplied to the generator; of a liquid fuel burner'for heating said generator by vaporization of liquid fuel to supply heat to the generator in proportion to the level of liquid fuel in the burner, apparams for feeding liquid fuel to said burner including a plurality of conduits connected to said burner, a device in each of said conduits to control flow of liquid fuel therethrough responsive to liquid level, and means for controlling flow of liquid through at least one of said conduits responsive to a temperature condition affected by said refrigeration system.

5. In a method of refrigeration which includes circulation of fluids, expulsion of refrigerant and evaporation of refrigerant to produce refrigeration in accordance with a quantity of energy supplying heat; that improvement which consists in producing the energy supplying heat by vaporization and combustion of liquid fuel at a rate proportional to the level of liquid fuel in a place of vaporization, supplying liquid fuel to said place of vaporization from a plurality of places of accumulation, conducting liquid fuel to said several places of accumulation at rates each responsive to a different liquid level in said places respectively, and controlling flow of liquid fuel from at least one of said places to said place of vaporization responsive to a temperature condition affected by the refrigeration produced.

HARRY r1. SHAGALOFF.

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