US1709588A

US1709588A - Refrigeration

Info

Publication number: US1709588A
Application number: US219193A
Authority: US
Inventors: Lenning Alvar
Original assignee: Electrolux Servel Corp
Current assignee: Electrolux Servel Corp
Priority date: 1927-09-13
Filing date: 1927-09-13
Publication date: 1929-04-16
Anticipated expiration: 1946-04-16

Description

A. LENNING April 16, 1929.

REFRIGERATION Filed Sept. 15, 1927 mm 2, mm 3 L W 2 I ii lA/l/E/VTUR om m 2 H A 3 n E i llll ll Ng ll l| ll V l Patented Apr. 16,1929.

UNITED STATES tnasss PATENT oFFicE.

ALV'AR LENNING, E NEWBURGH, NEW YORK, ASSIGNOR T0 ELECTROLUX SEEVEL CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE nnrmonaa'rron.

Application flledseptember 13, 1927. Serial No. 219,188.

My-invention relates to theart of refrigeration and particularly torefrlgerating ap= paratus of the absorption type and stall more particularly to absorptionapparatus whereir evaporation of the refrigerant is effected with the aid of a gas, inert with respect to 5 the refrigerant.

In a system of this type, a solution, consisting of the refrigerant dissolved in an ab-- 1 sorbing medium, is heated and the refrigerant driven out of solution. The refrigerant must necessarily have a lower boiling point than the absorbing medium, but nevertheless it is impossible toefiect'ively drive the former out of solution without vaporizing at least'a small amount of the atter. If-this absorbing medium so vaporized were allowed to pass through the system wlth the refrigerantand finally enter the evaporator it would, at the low temperature existing in the evaporator, absorb a great percentage of refrigerant and thus reduce the refrigerating efiect as the refrigerant so absorbed could not evaporate. Hence, it is necessary to separate the vaporized absorbing medium from the refrigerant and to'return the for-- mer thus separated to its proper place in the system. This separating process is commonly known as rectification. One of .the objects of my invention is to provide a sin ple and novel means for accomplishing this rectification and furthermore to insure constantrectification at varying loads. These and other objects and advantages of m invention will be apparent from the to lowing description and accompanying drawings, of which:

Fig.1 shows a cross-sectional elevational view of an absorption refrigerating -system embodying my invention; and

Fig. 2' shows a cross-sectional view of a modified form of rectifier which may be used in conjunction with the apparatus shown in Fig. l.

Referring more particularly to Fig. 1, reference character 10 designates a generator which is divided into a main generator 11 and an auxiliary generator 12 by the partition 13. A flue 14 extends centrally through generator 10.. In or below flue 14 is a suitable sourceof heat, as, for instance, the gas burner15. A thermo-si hon conduit 9 ex- 7, tends from within auxi iary generator 12 and communicates with the upper part of main generator 11. The lower portion ofv conduit 9 which is within auxiliary generator-12 is provided with one or more auxliary ports 8.

Reference character 16 designates generally the rectifier. Rectifier 16 comprises, in the embodiment shown in Fig. 1, a vertical cylindrical member 17 constituting a separati-ng chamber closed atthe top and bottom and in which is positioned a series of baflles- 18.- Member 17 is partially surrounded by a jacket 19. A conduit 20 isconnected to the upper part {of jacket or member 19 and to a coil 22 which is arranged in heat exchange relation with a cooling water conduit 21. Conduit 7 connects the bottomof coil 22 with the bottom ofjacket 19.

Parts

19, 20, 22, and 7 form anindependent self-cons tained system for vaporization, condensation and circulation of aliquid intthe presence of a non-condensable gas, as will"pr,esently he explained, which system is in heat transfer relation with the separating chamber 17 and comprises a first fluid containing mem: ber 19 and a second member 22, inter-con-I nected for communication, preferabl of circulatory nature. Rectifier 16' is p aced" at a somewhat higher elevation than generator 1O andis connected'to the upper part of main generator 11 by'the conduit 23.

A conduit 24 communicates with the upper part of member 17Iand passes in a gen erally downwardfdirection ilro "h water jacket 25 and communicates wit 1 he upper part of a closed'container 26. A conduit 27 communicates with the bottom of container 26 and passes within conduit 28, heat exchanger 29 and conduit 30 to within the upper part of evaporator 31. Evaporator 31 is a closed cylindrical member within which is positioned a series of disks 32. Disks 32 are provided with apertures 33 surrounded .by raised rims 34-. Evaporator 31 and a portion of heat exchanger 29 are inclosed in a chamber to be refrigerated designated by the broken-line rectangle 55.

A conduit 35 connects the bottom of evaporator 31 with space 36 formed within heat exchanger 29. Heat exchanger 29 consists of an outer cylindrical member 37 which is closed at both ends. Tube heads 38and 39 are positioned within member 37 and serve to support a number; of tubes to. Tubes 40 establish communication between space 41, which is formed between head 38 and the adjacent end of member 37, and

. from burner 15 serves to drive the ammoniasageway from

spaces

41 and 42 to space 36. -A vent conduit 45 connects the upper part of container 26 with space 36 in heat exchanger 29. A conduit 46 connects space 36 with the lower part of absorber 47. Conduit 30 connects space 42 with the upper part of evaporator 31.

Absorber 47 consists of a closed cylindrical member in which is positioned a series of disks 6' which may be similar to disks 32 in evapor or 31. Conduit 28 connects the top of absorber 47 with, space 41 in heat exchanger 29. Absorber 47 is partially surrounded by a water jacket 48. Coolin water is supplied to water jacket 48 throng a conduit 49 and is discharged through a conduit 50 to water jacket 25 from whence it is finally discharged through conduit 21.

A conduit 51 connects the bottom of absorber 47 with the upper part of auxiliary generator 12 and passes through jacket 52. A conduit 53 connects the bottom of main generator ll-with one end of jacket 52, while a conduit 54 connects the other end of jacket 52 with the upper part of absorber 47 and passes through water jacket 48.,

The apparatus operates as follows:

A solution which consists of a refrigerant,

for instance ammonia dissolved in an absorbmg medium for instance water, is contained in generator 10. The application of heat out of solution in main generator 11. This action vaporlzes a small amount of the water. The vaporous mixture of ammonia and water passes upwardly through conduit.

23 to separating chamber 17. In se arating chamber 17 the water vapor is con ensed to a liquid which runs back to main generator 11 through conduit 23, while substantially all of the ammonia vapor remains uncondensed. To accomplish the rectification,.it is essential that the temperature in rectifier 16 be maintained slightly higher, say 10 F. to 15 F than the boiling point of ammonia at the pressure existing in the apparatus. How this temperature is maintained independently of cooling water temperature will now be explained.

Jacket 19, conduit 20, conduit 7 and coil 22 form a closed system in which is contained a non-condensable gas and a liquid and vapor of this liquid. For the purpose of illustration, ammonia will be considered as the liquid and hydrogen as the non-condensable gas, although it is to be fully understood that other suitable combinations of fluids are contemplated and fall within the scope of the invention. For example, I may use nitrogen or methane combined with propane, butane, ethyl chloride or any other liquid having a low boiling point and which does not freeze readily. The temperature at which the ammonia or other fluid boils and hence the temperature at which the vapor thereof passes from the upper part of jacket 19 into conduit 20 is determined by the total or gage pressure existing in the system. The presence of the non-condensable hydrogen (or other gas) tends to maintain this pressure more orless constant, irrespective of fluctuations in the temperature of the cooling water, inasmuch as the pressure of the hydrogen constitutes the greater part of the total pressure within the system when the apparatus is in operation and the hydrogen pressure varies relatively little with changes of temperature as the hydrogen does not condense. If the hydrogen were not included in the system, the temperature of the cooling water would determine, to a large extent, the pressure and hence the boiling point of the ammonia. But with the hydrogen presout, the ammonia vapor cannot leave jacket 19 in any appreciable quantity until a cetain temperature has been reached, because there would be no boiling action, (only some diffusion taking place below the certain temperature), and hence the temperature in jacket 19 cannot fall below a predetermined minimum as long as warm vapor passes through member 17. The pressure that corresponds to this minimum temperature is determined chiefly by the hydrogen pressure in the rectification system and is so selected that the temperature in member 17 is slightly above the condensation temperature of the ammonia at the pressure existing within the refrigerating system proper. Hence the greater part of the ammonia vapor passes through member 17 uncondensed, while most of the water vapor is condensed. Baflles 18 prevent any water vapor passing through member 17 so rapidly that there is insufiicient time to allow the heat transfer, necessary for condensation, to take place between the water vapor and the medium in jacket 19. As the medium in jacket 19, here considered as ammonia, is evaporated, the vapor passes upwardly through conduit 20 and is recondensed by the cooling action of the cooling water in conduit 21. By properly adjusting the charge in the closed rectifier system, a more complete automatic rectification can be obtained than is possible by the use of part of the refrigerant proper for this purpose.

The vaporous ammonia passes out of the upper part of member 17 into conduit 24. an is condensed to a liquid in conduit 24 The ammonia evaporates in the r unabsorbed and being pro-cooled before t space 36 which has just by the cooling action of the cooling water in water jacket 25. The liquid ammonia runs from conduit 25 into container 26. As the upper part of container 26 is above the point of discharge of conduit 27 within evaporator 31, the ammonia runs by gravity from the container 26 through conduit 27 to the upper part of the evaporator. A small amount of noncondensable gas which is includcd'in the refrigerating system proper, for a purpose which will be explained presently, is apt to find its way from absorber 47 through generator 10 and rectifier 16 and finally is separated from the ammonia in container 26 and passes back through vent conduit 45 to heat exchanger 29 and thence to the absorber. Such gas is present in the generator when the unit is turned over in shipment and the vent serves to avoid trapping of this gas.

The liquid ammonia is distributed over disks 32 in the evaporator and comes in intimate contact with a gas, inert with respect to ammonia, for instance hydrogen, which is introduced through conduit 30. presence of, and ditl'uses into the hydrogen with a resultant drop in temperature which produces refrigeration within chamber 55. As the gaseous mixture of ammonia and hydrogen thus formed has a greater specific weight than the relatively pure hydrogen which enters through conduit 30, the mixture passes downwardly' through apertures 33 in disks 32 and through conduit 35' to space 36 in heat exchanger 22).

From space 36 the mixture passes through conduit 16 to the lower part of absorber 47.

In the absorber this m xture of ammonia and hydrogen is brought in intimate contact with water which contains but relatively little ammonia in solution and which is distributed over disks 5G. The water absorbs the ammonia while the hydrogen remains lighter, than the mixture it passes upwardly through the absorber. The heat which is liberated by the absorption process is carried awa chiefly by the cooling water in water jacket 48.

The hydrogen gas passes from the upper part of absorber 47 through conduit 28 to space 41 in heat exchanger 29. From space 41 the gas passes 42 and thence through conduit 30 to the upper part of evaporator 31. In heatexc ranger 29 the liquid ammonia in conduit 27 and the hydrogen gas in tubes 40 are both ey enter evaporator 31 by the cold ammonia hydrogen mixture in The strong solution of ammonia in water formed in absorber 47 passes out the bottom thereof through conduit 51' and enters auxiliary generator 12. The application of heat to the solution in auxiliary generator 12 I 52 an exchange of heat takes place ammonia vapor thus through tubes 40 to space left the evaporator..

vaporizes a portion of it and this vapor enters conduit 9 through the capillary ports 8. Slugs of liquid become entrapped between gas bubbles in conduit 9 and are carried upwardly therethrough bythe bubbles to the upper part of main generator 11. Here the ammonia is again driven out of solution and the now weak solution passes downwardly through the main generator and through conduit 53 to jacket 52. In jacket between the hot weak solution in the jacket itself and the cool strong solution in conduit,51. weak solution passes from jacket 52 through conduit 54 to the upper part of absorber 47. In conduit 54 the solution is further .coolcd before entering the absorber .by the cooling water in water jacket 48.

In Fig. 2 is shown a modification of rectifier 16 shown in Fig. 1. Cylindrical member 17 is partially surrounded by a jacket 57. A portion of conduit 21" which carries cooling water is placed in the form of a spiral around jacket 57. Conduit 21 may be welded to jacket 57 in order that good heat transfer will take place between the. two. A cylinder 58, open at'both ends and supported by legs 59, is placed 'around member 17 and within jacket 57. A condensable and a non-condensable gas, ammonia and hydrogen respectively, are sea-led within jacket 57. Cylinder 58 extends sufiiciently close to the bottom of jacket 57 so that the bottom of the cylinder is always submerged in the liquid ammonia. The hydrogen serves the same purpose as it did in the rectifier shown in Fig. 1, namely of tending to maintain an almost constant pressure within jacket 57. The latent heat of vaporization of the water vapor which passes through member 17 vaporizes some of the liquid ammonia in jacket 57. The

formed passes upwardly through the annular space between member 17 and cylinder 58 and into the annular space between cylinder 58 and jacket 57, in the upper part of which it is recondensed to a liquid by the cooling action of the cooling water in conduit 21 and the liquid ammonia thus formedcollects in the bottom of jacket 57.

While I have illustrated and described two more or less specific forms of my invention, it is to be understood that I am not limited by the structure so disclosed. For example,'other methods of cooling, such as by air, may be employed to cause the liquefaction of the condensable gas in the rectifier without detracting from the spirit of the invention. It will be obvious thatmany variations of the structure of the rectifier are possible within the scope of the invention. I am aware of application Serial No. 132,160 filed August 28, 1926, by Carl Georg.

for instance The gas.

of the liquid Y therein.

Having thus described my I claim is: r

1. A rectifier for absorption refrigerating apparatus comprising a separating chamber, a source of cold and-a self-contained closed circuit system in heat transfer relation with said separating chamber and said source containing a liquid and a non-condensable invention, what 2. Absorption refrigerating apparatus comprising a first system including a generator, a condenser, an evaporator, an absorber, conduits connecting the aforementioned parts including a conduit for conveying vapor from the generator to the condenser, said first system containing liquid and a non-condensable gas and a second system containing liquid and a non-condensable gas in heat transfer relation with said conduit.

3. That improvement in the art of refrigerating with the aid of an absorption system which consists in vaporizing a liquid in the presence of a'non-condensable gas by a mixture of refrigerant and entrained vapor of absorption liquid to separate the absorption liquid from the refrigerant while maintaining the first mentioned liquid and the refrigerant in separate closed systems.

4. A rectifier-for absorption refrigerating apparatus comprising a separating chamber, means to supply vapor to and withdraw vapor and liquid from said separating chamber, a first memberin heat transfer relation with said separating chamber containing a liquid independent of fluid in said separating'chamber and a non-condensable gas, a second member adapted to condense vapor formed in the first member and means of-communication between the said members. 7

5. A-rectifier for absorption refrigerating apparatus comprising a separating cham-- ber, means to supply vapor vapor and liquid from said to and withdraw separating chamher, a first member in heat transfer relation with said-separating chamber containing a liquid independent of fluid in said separating chamber and a non-condensable gas, a second member adapted to condense vapor of the liquid, formed in the first member and a plurality of conduits connecting said members to form a circulation system therewith and therebetween.

6. A rectifier-for absorption refrigerating apparatus comprising a separating chamber forming part of a refrigerant system, means duit, means to supplycooling water to and withdraw cooling water from said cooling Waterconduit, a second memberadapted to hold fluid and arranged in heat transfer relation with said cooling water conduit and means of communication between said members, said members and the means of communication therebetween forming an independent system, the arrangement being such that vapor formed in said first member is condensed iu'said second member.

7. That improvement in the art of refrigerating with the aid of an absorption system which consists in vaporing a liquid in the presence of a non-oondensable gas by a mixture of refrigerant and entrained vapor of absorption liquid in heat exchange relation with said first mentioned liquid to separate the absorption liquid from the refrigerant, condensing the vaporized liquid and returning the condensed liquid into heat exchange relation with the mixture of refrigerant and vapor of absorption liquid while maintainingthe first mentioned liquid and the refrigerant in separate closed systems. v

8. Absorption refrigerating apparatus comprising a first system including a gen erator, a condenser, an evaporator, an absorber, a rectifier separating chamber, said first system containing liquid and a noncondensable gas, a second system containing liquid and a. non-condensable gas arranged in heat transfer relation with the rectifier separating chamber of the first system, said second system including a member to be cooled and cooling means arranged to cool, in series, the absorber and condenser of the first system and the said member of the second system.

9. Absorption refrigerating apparatus comprising a separating chamber,- means to supply a mixture of refrigerant and entrained vapor of absorption liquid to said chamber and'to withdraw vapor and liquid from said chamber and a separate member in heat exchange relation with said chamher containing a liquid and a non-condens able gas and means to cool the fluid in said signature.

ALVAR LEN N IN G.