US2300579A - Refrigeration - Google Patents

Description

Nov. 3, 1942. A. LENNING 2,300,579

' REFRIGERATION Filed Aug. 17, 1957 2 sheets-sheet 1 INVENTOR .aem

Id ATTORNEY Nov. 3, 1942. A. LENNING 2,300,579

REFRIGERATION Filed Aug. 17,1937 2 Sheets-Shed 2 INVEN 0R eddy effect produced Patented Nov. 1942 UNITED STATES PATENT'OFFICE REFRIGERATION Alvar Lenning,'Stockholm, Sweden, assignor, by mesne assignments, to Servel, Inc., New York, N. Y., a corporation of Delaware Application August 17, 1937, Serial No. 159,450 In Germany September 3, 1936 9 Claims.

through a conduit 5. gas heat exchanger l6, and a vertically extending conduit ll which is connected at its lower end with the lower end of an absorber l8 provided with a plurality of cooling fins l9. In absorber l8 refrigerant vapor is absorbed into solution by a suitable liquid absorbent, suchas water, which enters through a' conduit 20. The inert gas, which is practically insoluble and weak in refrigerant, is returned to the upper part of cooling element Ill through a conduit 2|,

- gas' heat exchanger 16, and a conduit 22; and the permitting the flow of liquid through a lower part of each dam. By providing dams of this character in the path of-fiow of liquid between the barriers, not only is the liquid surface increased,-

but a film which forms on the surface of the liquid is effectively broken up when liquid flows from one pool to the successive pool due to the by flow of liquid underneath the dams.

I preferably employ a helical memberwithm a absorption liquid flowing downward through the absorber i8 in counter-flow to the gas mixture becomes enriched through the lower end of conduit ll. into an accumulation vessel 23. From the accumulation vessel 23 enriched absorption liquid is conducted through a liquid heat exchanger'fl to. acoil 25 conduit to provide dams which permit the flow of liquid through a lower part of each dam. In addition to providing fresh liquid surfaces, ahelical member possesses the additional advantage that a whirling motion is imparted to the gas to improve further the surface contact between the gas and liquid.

The invention, together with the above and other objects and advantages thereof. will be better understood from the following description and accompanying drawings forming a part of this specification, and of which Fig. 1 diagrammatically illustrates an absorption refrigeration apparatus embodying my invention: Fig. 2 is an enlarged fragmentary sectional view of a part of the cooling element and absorber shown in Fig. l to illustrate more clearly one embodiment of my invention; and Figs. 3 and 4 are sectional views similar to Fig. 2 illustrating modifications of the I enclosed space H which may form a food storage compartment of a thermally insulated cabinet I2. Refrigerant fluid, such as ammonia, passes through a conduit l4 into the cooling element ill and evaporates and diffuses therein into an inert gas, such as hydrogen, to produce a refrigerating effect. The resulting gas mixture of refrigerant which is disposed about a flue '26 which extends vertically upward through a generator 21.

By heating generator 21, as by a gasburner 28, for example, refrigerant vapor-and absorption liquid are raised by vapor lift action through conduit 29 from coil 25 to the upper part of generator 21. Liberated refrigerantvapor entering generator 21 through conduit 29, as well as refrigerant vapor expelled from solution in the generator, flows upward into an air-cooled condenser 30. Refrigerant vapor is liquefiedin condenser 30 and returned-to cooling element ill through conduit M to complete the refrigerating cycle. The weakened absorption liquid from which refrigerant has been expelled is conducted from generator ,2! through conduit 3|, liquid heat exchanger 24, and conduit 20 into the upper part of absorber l8.

A vessel 32 is connected by a conduit 33 to the lower partof condenser 30 and by conduit 34 to v vertical plane.

and inert gas flows from cooling element I0 the gas circuit, as at the conduit IT, for example, so that any inert gas which may pass into the condenser can flow into the gas circuit. Refrigerant vapor not liquefied in condenser 30 flows through conduit 33 to displace inert gas in vessel 32 and force such gas through conduit 34 into the gas circuit, so that the total pressure in the a plurality of inclined conduits 35 which are connected to each other and arranged in the same parts of conduit 35 are indented at spaced intervals at 36 to provide barriers over which liquid must flow. Within each conduit 35 is arranged in refrigerant and passes- The absorber i8 is of the coil type and includes Referring to Fig. 2, the lower a helical member or coil 31 having the lower parts of successive turns disposed between the indentations 36. The helical member 35 is arranged within conduit 35 in such a manner that the member irregularly contacts the inner wall of the conduit to provide spaces 33 between the member and inner wall of the conduit.

By providing the indentations 36 and helical member 31, the normal downward flow of liquid in conduits 35 is retarded by the indentations 33. Theliquid passes over the barriers formed by the indentations-36, and the flow of liquid is subsequently checked by the dams 38 formed by the lower parts of helical member 31. Liquid flows underneath the dams due to the narrow gaps 33 between the lower parts of helical member 31 and the inner wall of conduit 34 whereby the flow of liquid is throttled. The throttling of liquid flow produces an eddy efiect and changes the rate of flow of liquid. With flow of liquid taking place in conduit 35 in the manner just described, the gas and liquid surface contact is improved considerably because of the destruction of a film which forms on the surface of the liquid. This film is due to the absorption of refrigerant gas at the surface of the liquid, and it is a distinct advantage to break up this surface film containing a relatively high amount of refrigerant so 'that fresh gas and liquid contact surfaces are provided.

The film which forms at the surface of the liquid contacts the helical member 31 at the dams 33 and, due to the manner of liquid flow, is drawn downward into the liquid at the dams so that it is broken up and a more uniform absorptionsolution is produced. The breaking up of the surface film is also aided by the fact that the current of liquid is divided into a number of partial currents when passing underneath the dams 33 due to the irregular contact effected between'the helical member 31 and inner wall of the conduit 35. The helical member 31 also imparts a whirling motion to the gas flowing 7 through the conduit to further. improve the contact between the gas and liquid.

In Fig. 3 I have shown a modification of the invention in which a helical band or strip 43 is arranged within conduit 35 instead of a helical wire. I The strip 40 is disposed within conduit 35 in such a manner that one longitudinal edge thereof bears against the inner wall of the conduit. In this longitudinal edge are formed notches or recesses 4| through which liquid must pass. The flow of liquid is accelerated at the recesses 43 to produce an eddy effect whereby the surface film is effectively broken up and a more uniform absorption solution is produced.

In Fig. 4 I have shown a further modification in which a helical member 32 is disposed within conduit 35. The.helical member 32 is twisted and formed of a number of strands or smaller wires which are preferably helically wound in opposite directions. By employing a twisted wire of this character small gaps: are formed at the inner wall of conduit 35 to permit flow of liquid through the lower parts of the dams formed between the indentations 33.

The provision of a helical member of the character shown in Figs. 2 to 4 inclusive increases the liquid surface contact considerably. When liquid passes over the barriers formed by the indentations 35, the liquid tends to run up along the helical members at the dams formed by these members. Since the flow of liquid is effectively at these regions and is subsequently drawn downward into the narrow gaps or spaces beneath the dams to produce a relatively strong eddy effect.

In making the improved absorber just described, the helical members or coils may be formed to the desired shape and inserted into the conduits. The indentations 36 may then be made in conduits 35 and the cooling fins l3 thereafter secured in place. If desired, the helical coils may be screwed into the conduits after the indentations 35 have been formed. The pitch of the helical membersmay be made 1, 2. or 3 times the distance between two indentations 36 and the helical members screwed into position in such a manner that the wires will not strike the indentations 36.

In view of the foregoing, it will be undertsood that I have provided an improvement to increase the surface contact between a gas and a liquid which may be used in the evaporator or cooling element ID as well as the absorber l3. WhileI have shown and described several embodiments of my invention, such variations and modifications are contemplated as fall within the true spirit and scope of my invention.

What is claimed is:

1. Absorption refrigeration apparatus having a circuit for circulation of a gas and including a conduit having an inlet and outlet at different elevations, a member for introducing liquid in said conduit for downward flow therein in the presence of said gas, a helical wire disposed within said conduit and arranged to contact the inner wall thereof irregularly to provide spaces between the lower parts of successive turns and the inner wall of said conduit, the lower parts of said wire serving as dams and said spaces permitting fiow of liquid below said dams, and barriers in said conduit at spaced intervals between said dams to form a series of pools in the path of flow of liquid.

2. Absorption refrigeration apparatus having a circuit for circulation of a gas and including a conduit having an inlet and an outlet at different elevations, a member for introducing liquid in said conduit for downward flow therein in of successive turns of saidhelical strip serving as dams in the path of flow of liquid and said notches or openings permitting the flow of liquid at the lower parts of said dams.

3. Absorption refrigeration apparatus having a circuit for circulation of a gas and including a conduit having an inlet and an outlet at different elevations, a member for introducing liquid in said conduit for downward fiow therein in the presence of said gas, and a helical strip within said conduit and having one longitudinal edge thereof bearing against the inner wall of said conduit, said strip extending inwarding from the inner wall of said conduit, and said strip having notches along the longitudinal edge bearing against the inner wall of said conduit.

4. Absorption refrigeration apparatus having a circuit for circulation of a gas and including a conduit having an inlet and an outlet at different elevations, a member for introducing liquid in saidconduit for downward fiow therein in the presence of said gas, and a helical wire extending axially within said conduit and contacting of said wire provide dams for liquid at spaced throttled at the dams, liquid tendsto accumulate intervals, said wire comprising a plurality of closely woven twisted smaller wires whereby a plurality of small gaps are formed at said dams to permit flow of liquid therethrough.

.5. Absorption refrigeration apparatus having a circuit for circulation of gas and including a conduit having an inlet and outlet at different elevations, ajmember for introducing liquid in said conduit for downward flow therein in the presence of said gas, said conduit having indentations at spaced intervals to provide barriers over which liquid must flow, and means disposed between said indentations to provide dams having openings in the lowerparts thereof.

6. Absorption refrigeration apparatus having a circuit for circulation of a gas including a conduit having an inlet and an outlet at different elevations, means for introducing liquid in said conduit for downward flow through said conduit in the presence of said gas, said co'nduit having barriers at spaced intervals to form a series of pools in the path of flow of liquid,

' and a fixed member in said conduit having parts disposed between said barriers in a manner to project into said pools to cause turbulence in flow of liquid in said pools, said parts being connected by other parts disposed above said pool forming barriers.

7. In refrigeration apparatus including .a gen therein; barriers atspaced intervals in said con- -8.l. A-bsorption refrigeration ap aratus having a circuit for circulation of inert gas and includmg ampart arranged for gravity flow of liquid therethr'oug'h, means to introduce-liquid in .said

partforgravity flow therein in the presence of,

' said gasasald part having barriers at spaced in- "extending over said barriers and having fixed parts projecting downward between said barriers into'fsaid pools to produce an eddy effect in tervalsain the path of flow'of liquid to form a plurality of pools and means including a member liquidggflowing in said pools.

"a Absorption refrigeration apparatus having a circuit for inert gas including a part arranged forgravity flow of liquid therethrough, a means' to introduce liquid in said'partfor gravity fiow therein in the presence of said gas, .said part having inward projections forming barriers at spaced in'tervals in' the path of flow of liquid to'forin ai series of pools, and means in said part erator, a condenser, an'evaporator, an absorber,

and members connecting 'the aforementioned parts to form a complete system for circulation of a refrigerant and absorption liquid, and an inert gas, said absorber including a conduit ar-,

ranged for gravity flow of absorption liquid shaped to extend upward over said'barriers and downward between said barriers so as to project into said' pools and create turbulence of liquid flowingin said pools. I v

. ALVAR LENNING.

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