US2368455A - Refrigeration - Google Patents

Description

Jan. 30, 1945. P. EDBERG 2,368,455

REFRIGERATION Filed Sept. 25, 1941 2 Sheets-Sheet 1 BY fiILNVZENTOR ZWMZZW M ATTORNEY Jan. 30, 1945. P. EDBERG 2,368,455

REFRIGERATION Filed Sept. 25, 1941 2 Sheets-Sheet 2 INVENTOR BY (a lfim M ATTORNEY Patented Jan. 30, 1945 nnrmeeaarron Per Edberg, Evansville, Incl, asalgnor to Servel,

Inc., New York, N. Y., a corporation of Delaware Application September 25,1941, Serial No. 412,228

9 Claims. (Cl. 52-119) My invention relates to refrigeration, and more particularly to splitting or dividing of liquid in refrigeration systems into a plurality of paths of flow.

It is often desirable in refrigeration systems to divide a stream of liquid into a plurality of paths of flow. This is especially true in absorption refrigeration systems of large size, because in such instances the manner in which liquid flow is effected determines to a great.

extent the efllciency and capacity of a system, the arrangement of component parts of a system, and the amount of space a system of a given capacity will occupy.

In accordance with the invention liquid flowing in a refrigerating system operating at exextremely' low pressures is divided into a plurality of paths of flow through several tubes in each of which the liquid flows upwardly. While the tubes employed to provide the several paths of flow offer substantially no resistance to flow of liquid, the fact that the several streams of liquid flow to a region at which the vapor pressure is less than the vapor pressure of the liquid in the several streams causes some of the upwardly flowing liquid to vaporize, whereby the liquid entering the region is partially cooled down toward a temperatur corresponding to the vapor pressure existing at the region. The vapor formed in the tubes builds up resistance to flow of liquid which is advantageously utilized to bring about proper division of liquid into the several paths of flow, that is, vapor may form at the same time or alternately in the different tubes so that over a period of time the desired quantity of liquid flows through each of the several paths of flow.

Dividing liquid in the manner just described lends itself to an arrangement whereby a flash chamber can be provided at the region to which the several streams of liquid are introduced, so that further vaporization of liquid can take place in such chamber without affecting the subdivision of liquid into the several paths of flow. With such vaporization of liquid in the flash chamber additional cooling of liquid is effected to bring the liquid down to a temperature corresponding to the vapor pressure existing at the region.

It is, therefore, an object of the invention to provide in an absorption refrigeration system an improved liquid divider of the character lust described.

The novel features which I- believe to be characteristic of my invention are set forth with particularity in the claims. The invention, both as to organization and method, together with the above and other objects and advantages thereof, will be better understood as I next describe my improved liquid divider embodied in an absorption refrigeration system like that described in application Serial No. 239,762 of A. R. Thomas and P. P. Anderson, Jr., filed November 10, 1938, now Patent No. 2,282,503 granted May 12, 1942.

In the accompanying drawings forming a part of this specification, I

Fig. 1 more or less diagrammatically illustrates an absorption refrigeration system in which is embodied a liquid divider embodying my invention;

Fig. 2 is an enlarged fragmentary view taken at line 2-2 of Fig. 3, partly in section, to illustrate the manner in which several streams of liquid.- are introduced into the upper part of the evaporator shown in Fig. 1;.

Fig. 3 is a vertical view of an end of the evaporator shown in Fig. 1, partly broken away and in section, to illustrate more clearly the manner in which flow of liquid is effected in the evaporator;

Fig. 4 is a vertical view, partly in section, taken at line 4-4 of Fig.3;

Fig. 5 is a horizontal sectional view,.taken at line 5-5 of Fig. 6, to illustrate the flash chamber associated with the evaporator shown in Fig. 1 and into which several streams of liquid flow;

and

Fig. 6 is a vertical sectional view, taken at line 6-6 of Fig. 5, to illustrate the flash chamber more clearly.

Referring to Fig. 1, the .invention is embodied in a two-pressure absorption refrigeration system like that described in the Thomas and Anderson application referred to above. A system of this typeoperates at low pressures and includes a generator or vapor expeller III, a condenser ll, an evaporator l2, and an absorber ll which are interconnected in such a manner that the pressure differential in the system is maintained by liquid columns.

The disclosure in the aforementioned Thomas and Anderson application may be considered as being incorporated in this application, and, if desired, reference may be made thereto for a detailed description of the refrigeration system. In Fig. 1 the generator ll inclues. an outer shell 15 within which are disposed a plurality of veriical riser tubes l6 having the lower ends thereof communicating with a. space I! and the upper ends thereof extending into and above the bottom of a vessel [8. The space H! surround- 1111; the tubes IS in shell 15 forms a chamber 19 to which steam is supplied through a conduit 20. The chamber is provides for full length heating of the tubes 3 with the toppart of the chamher being vented at 2| to atmosphere. A conduit 22 is connected to the bottom part of shell 15 for draining condensate from chamber [9.

The system operates at a partial vacuum and may contain a water solution of refrigerant in absorption liquid, such as, for example, a water solution of lithium chloride or lithium bromide or a suitable mixture of such salts. With steam being supplied to chamber I! through conduit 20 at atmospheric pressure, heat is applied to tubes l whereby water vapor is expelled from solution, such expelled vapor being efl'ective to raise liquid absorbent by gas or vapor-lift action with the expelled water vapor forming a central core within an upwardly rising annulus of the liquid. The expelled vapor passes from the upper ends of the tubes l6 into the vessel l8, and thence flows through a conduit 23 into condenser II in which the expelled vapor is liquefied. The condensate formed in condenser II flows through a conduit 24, vessel 25, riser imbes 26v and 21, flash chamber 28 and conduits 29 and 30 to the top part of evaporator l2, as will be described presently.

The refrigerant evaporates in evaporator l2 to produce a refrigerating or cooling eifect with consequent absorption of heat from the surroundings, as from a stream of air flowing over the exterior surfaces of the evaporator. The refrigerant vapor formed in evaporator l2 flows therefrom to the absorber l4 into which absorption liquid is introduced at the top part through a conduit 3|. The entering absorption liquid flows into a vessel 32 in which liquid is distributed laterally or crosswise of a plurality of vertically disposed pipe banks 33 which are arranged alongside each other. The liquid flows from the center part of vessel 33 into laterally disposed end chambers 34 and thence through conduits 35 into a plurality of liquid holders and distributors 35 which extend lengthwise of and above the uppermost horizontal tubes of pipe banks 33. Absorption liquid is siphoned over the walls of the liquid holders 36 to efiect complete wetting of the uppermost horizontal tubes. Liquid drips from each horizontal tube onto the next lower tube whereby all of the tubes are wetted with a film of liquid.

The refrigerant vapor formed in evaporator l2 passes through end headers 31 into the absorber l4 in which the vapor is absorbed into the absorption liquid. The absorption liquid is conducted from absorber I4 through a conduit 38, a first passage in liquid heat exchanger 39, conduit 40, vessel 4|, and conduit 40, vessel 4|. and conduit 42 into space ll of generator l0.

'Reirigerant vapor is expelled out of solution ascaess absorber M. This circulation of absorption liquid results from the raising of liquid in riser tubes l5 whereby the liquid can flow to absorber l4 and return from the latter to generator in by force of gravity. The upper part of vessel 3! and vessel I8 are connected by a conduit 44, so that the pressure in vessel 8! is equalized with the pressure in the top part of generator I 0 and condenser I.

The absorber I4 and condenser H constitute heat rejecting parts of the refrigeration system and are cooled by a suitable cooling fluid, such as water, for example, which enters the bottom parts of the pipe banks 33 through a conduit 45 and manifold 46 and leaves the top parts of the pipe banks through a manifold 41 and conduit 48. The conduit 48 is connected to condenser ll whereby the same cooling fluid can be utilized to cool the absorber I4 and condenser H, the cooling fluid then leaving the condenser through a conduit 43.

The system operates at low pressures with the generator Ill and condenser ll operating at one pressure and the evaporator 12 and absorber l4 operating at a lower pressure, the pressure differential therebetween being maintained by liquid columns. Thus, the liquid in the U-trap formed by conduit 24, vessel 25 and riser tubes 26 and 21 maintains the pressure differential between condenser H and evaporator l2, the liquid column in conduit 33 maintains the pressure differential between the outlet of absorber l4 and generator Ill, and the liquid column formed in conduit 3| maintains the pressure difie'rential between the inlet of absorber l4 and the upper part of generator HI. During operation of the system, the liquid columns may form in conduits 38, 43 and 24 to the levels 2:, y and z, for example.

The evaporator l2 includes a plurality of horizontal tubes 50 to which are secured a plurality of heat transfer flns 5|. The ends of tubes 50 pass through and are secured in openings formed in headers 31 at each end of the evaporator. The liquid flowing to evaporator l2 through conduits 29 and 30 is conducted to liquid holders 52 and 53 located in the top part of one of the headers 31. The liquid holders 52 and 53 are connected to and supported by two of the uppermost horizontal tubes 50.

The tubes 50 are connected at their ends to provide two separate paths of flow for the liquid introduced into the holders 52 and 53. Referring more particularly to Fig. 3, the two right-hand banks of tubes 50 form a first path of flow for liquid and the three left-hand banks of tubes form a second path of flow for liquid. In the path of flow formed by the two right-hand banks of tubes. liquid flows through successively lower tubes in the two banks through suitable end connections. This is accomplished by providing at the ends of end tubes 50 open top buckets 54 each formed with an opening in a bottom part thereof to receive an end of a tube 50 in one of the banks of tubes. The buckets 54 are also notched to receive an end of the next higher tube 50 in the other bank of tubes forming a part of the path of flow being described.

In the path of flow formed by the three lefthand banks of tubes 50, open top buckets 55 and 56 are provided in the headers 31'. These buckets are generally similar to the buckets 55 with openings or notches formed in both ends to receive the ends of tubes 50 in difl'erent banks of tubes.

The buckets l8 and 88 serve as connections through which liquid is directed and qaused'to flow through successively lower tube?" in the;

three left-hand banks of tubes.

The two paths of flow for liquid formed by the tubes 68 are indicated as A and B in Fig. 2

. to which liquid is supplied from the liquid holders and 68. No barriers or dams of any kind are provided in tubes 50 to cause shallow pools of liquid to be formed therein. The tubes 68 are as level as possible and the liquid ,merely trickles along the bottom parts thereof. The tubes are preferably grooved to provide small capillary passages at right angles to the lengths of the tubes, so that complete wetting of the inside walls of the tubes is effected in the manner de-- scribed in O'Brien application Serial No. 411,459, filed September 19, 1941. vaporization of refrigerant takes place in tubes 56 with consequent absorption of heat from the surroundings, as explained above. Refrigerant vapor flows out of II is condensed in condenser H and flows through conduit 28 into vessel 26, and thence divides intotwo paths of flow in riser tubes 28 and 21. The vessel 26 serves to reduce the velocity pressure of the liquid before division of liquid is eifected into the riser tubes 26 and 21. The liquid from riser tube 21 enters one of the spaces 62 in flash chamber 28 from which it flows through conduit 26 to the liquid holder 62. Likewise, the liquid from riser tube 26 enters the other space 62 in flash chamber 28 from which it flows through conduit 30 to'the other liquid holder 58.

, rator 12 are so located and positioned that, when tubes 60 and from the open top buckets 64, 66,

and 56 into the headers 31 from which the vapor passes into absorber M for absorption by the absorption solution. Liquid refrigerant passes from each tube 50 to the next lower tube in its path of flow, and any refrigerant discharged from the lowermost tubes 50 in the two paths of flow A and B passes directly into absorber ll.

Referring to Fig. 2, the arrows indicate the direction in which a stream of air is caused to flow over the surfaces of tubes 50 and heat trans fer flns 5| of evaporator l2. The stream of air first ilows past the two banks of tubes forming the path of flow A and then past the three banks of tubes forming the path of flow B. The air is warmest when it comes in thermal 0on tact with the tubes forming the path of flow A and, after coolingof air is effected by the first two banks of tubes, air at a lower temperature comes in thermal contact with the remaining three banks of tubes forming the path of flow B.

In order to deliver liquid from condenser l I to both liquid holders 52 and 53 in evaporator l2, the liquid flowing from the condenser H is split or divided into a plurality of paths of flow by connecting conduit 24 t the bottom partof a vessel 25 and connecting two upwardly extending riser tubes 26 and 21 to the upper part of this vessel.

The upper ends of riser tubes 26 and 21 are connected to the bottom part of another vessel 28 which serves as a flash chamber and within which is provided a dividing wall or partition 60.

To the top edge of partition 60 is fixed a baille plate 6| having oppositely inclined sides which the columns of liquid built up in the up-legs or riser tubes 26 and 21 of the U -trap formed by the parts connecting the condenser II and evaporator I2, liquid will always overflow into the liquid holders 52 and 53 from the liquid columns at the upper ends of riser tubes 26 and 21 for any pressure differential between evaporator l2 and condenser ll ranging from zero to maximum. Stated another way, when operation of the system is first started and the pressure differential between condenser H and evaporator 12 is zero, the column of, liquid formed in conduit 24 will be sufllciently high to cause condensate to overflow by gravity from the upper ends of riser tubes 26 and 21 into the upper part of evaporator l2. After the pressure diiferential builds up in the system so that the pressures in condenser ll andevaporator l2 are in the neighborhood of mm. and 9 mm. mencury, for example, and the liquid level in conduit 28 is at some point, such as 2, liquid will still flow by gravity from the condenser to the evaporator by overflowing into the latter from the upper ends of riser tubes -26 and 21.

Since the condensate flowing from condenser II to evaporator 12 is passing from the high to extend downwardly into each of the spaces 62 at opposite sides of the partition. Below each side of baille plate 6| a second baffle plate 63 is disposed in each of the spaces 62, as shown most clearly in Fig. 6. A pipe 64 is connected at its upper end to the flash chamber 28 and at its lower end to one of the headers 31 of-evaporator l2. 6

Referring more particularly to Figs. 5 and 6, it will be seen that the upper endsof riser tubes 26 and 21 and also conduits 29 and are connected to spaces 62 at opposite sides of the partition 60. The lower ends of conduit 29 and 20 are connected to the liquid holders 52 and 63, as explained above.

During operation of the refrigerationsystem, assuming that the system is charged with a water solution of a lithium salt, for example, water vapor expelled from solution in generator the low pressure side of the system, and the system is operating at extremely low pressures and at a partial vacuum, there is a tendency for liquid to vaporize in riser tubes 26 and 21 due to decrease in pressure on the rising liquid therein. With vaporization of liquid occurring in the riser tubes 26 and 21 some cooling of liquid is effected on its way to evaporator 12. However, when the liquid enters flash chamber 28 associated with evaporator l2, the liquid usually has not cooled down to a temperature corresponding to the vapor pressure in the evaporator. The flash chamber 28 is provided .so that vaporization of liquid can take place therein without disturbing the flow of liquid in the evaporator. This will readily be appreciated when consideration is given to the fact that in a system like that described, with the evaporator at a temperature of about 50 F. and at a pressure of approximately 9 mm. mercury, the ratio of vapor volume to liquid volume is on the order of 100,000 to 1', so that a small amount of liquid evaporating forms a lot of vapor. Under these conditions the refrigerant supplied to the evaporator changes from liquid to gas phase by vaporization which is in the nature of boiling as contrasted with the manner in which evaporation of liquid takes place solely by surface phenomenon.

The flash chamber 28 serves as a precooler for liquid flowing to evaporator 12, the heat of cooling of the liquid. The bames GI and ii are provided to separate any liquid spray from vapor that passes through pipe 64,. because entrainment of liquid with vapor flowing through this pipe constitutes a loss of such liquid.

By introducing liquid into the evaporator in several paths of flow, that is, at opposite sides of partition 60 in flash chamber 28, no upset of liquid division can take place due to formation of vapor in the flash chamber. The liquid remains divided in the spaces 82 and flows from these separate spaces through conduits 29 and 30 into the liquid holders 52 and 53. It has been found that with this arrangement the liquid is cooled sufficiently in the flash chamber so that when it enters the liquid holders 52 and 53, the liquid is at a temperature corresponding to the vapor pressure in the evaporator.

When a single stream is split and divided into a plurality of streams in which equal division of liquid flow is desired, it is usually extremely important that the split streams ofler identically the same resistance to flow of liquid. If there is any unbalance or difference in the resistance offered to liquid how in the several streams, then a greater amount of liquid will tend to flow through the stream offering the lesser resistance to liquid flow.

In the liquid divider provided the riser tubes 26 and 21 are of such size that there is substantially no resistance to flow of liquid. However, the vapor formin in the tubes 26 and 21 does build up resistance to flow of liquid which is appreciably greater and clearly dominates the negligible resistance to liquid flow produced by the tubes themselves. Vapor may form at the same time or alternately in the tubes 26 and al to build up resistance to liquid flow, with the result that over a period of time substantially equal division of liquid flow in the tubes is efiected. Hence, in the event there is a tendency for a greater amount of liquid to flow through one riser tube than the other, even with the tubes being approximately the same: size, the resistance to liquid flow resulting from formation of vapor in the tubes counteracts any tendency for unequal division of liquid to occur, whereby the vapor is efiectively utilized to cause and bring about proper division of liquid.

In view of the foregoing, it will be understood that steady and constant flow of liquid does not occur in riser tubes 26 and 21. The action that takes place may be likened to that of several geysers in which violent boiling of relatively small amounts of liquid occurs to produce relatively large volumes of vapor. This is due to the fact that the liquid risingin tubes 26 and 27 tends to remain as liquid above its boiling temperature, and when vaporization does occur it is instantaneous and sudden. With the occurrence of each geyser effect some water is pushed from the upper ends of riser tubes 28 and 27 so that the pressure at any region in the liquid columns becomes reduced to bring about a condition in which more boiling and vaporization of liquid is efiected. As pointed out above. it is the forming of vapor in the manner just described that builds up momentary resistance to liquid flow which is intermittent in character and suflicient to insure that substantially equal division of liquid flow is effected through the tubes 26 and 2?.

With approximately half of the liquid being supplied to each of the liquid holders 52 and 53, it will now be understood that the path of how A uses up such a quantity of the liquid that it adequately takes care of the two banks of tubes forming this path of flow. While the path of flow B is supplied with the remaining half of the liquid, this amount of liquid adequately takes care of three banks of tubes because the air is at a lower temperature when it comes in contact with the banks of tubes forming the path of flow B.

In view of the foregoing, it will now be understood that partial vaporization of liquid in the upper parts of riser tubes 26 and 21 is the main factor eilecting regulation of liquid flow in these riser tubes. With liquid being supplied from the same source to riser tubes 26 and 21, the quantity of vapor formed in each riser tube will be the same as in the other because the initial temperature of the liquid entering the tubes is the same and the reduction in pressure is the same through the parallel paths of flow.

By employing tubes of diiIerent size so that unequal resistance to flow of liquid is built up by the vapor formed in the riser tubes, a predetermined unequal division of liquid can be effected. When equal division of liquid is desired, riser tubes of substantially the same size are employed with the tubes in effect constituting long orifices. The formation of vapor increases the resistance to liquid flow to such an extent that the small difierence between individual tube resistances does not appreciably affect the division of liquid.

While a single embodiment of the invention has been shown and described, it will be ap parent that 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. A multi-pressure absorption refrigeration system having a generator and a condenser adapted to operate at one pressure and an evaporator and an absorber adapted to operate at a lower pressure, and connections for the aforementioned parts to provide circuits for circulation of refrigerant and absorption liquid, the connection through which liquid is conducted from the condenser to the evaporator including a U-trap having a down-leg and an up-leg comprising a plurality of parallel branches for supplying liquid to difl'erent parts of the evaporator, said parts and connections being so constructed and arranged that the liquid flowing into said branches has a vapor pressure greater than the vapor pressure in the evaporator whereby vaporization of liquid takes place in said branches to produce vapor blocking therein to promote division of liquid into the branches.

2. A multi-pressure absorption refrigeration system having a generator and a condenser adapted to operate at one pressure and an evaporator and an absorber adapted to operate at a lower pressure, and connections for the aforementioned parts to provide circuits for circulatlon of refrigerant and absorption liquid including conduit means to form liquid columns to maintain the pressure difierential, the part of said conduit means through which liquid is conducted from the condenser to the evaporator including a U-trap having a down-leg and an upleg comprising a plurality of branches into which upwardly rising liquid is divided into a plurality of paths of flow for supplying liquid to different parts of the evaporator, the system being so constructed and arranged that for the pressure existing in the evaporator vaporization of liquid therein is in the nature of boiling as contrasted with the phenomenon of surface evaporization, whereby liquid rising in said branches and flowing thereto from the condenser vaporizes to produce vapor blocking to promote and bring about dividing of liquid into said branches.

3. An absorption refrigeration system having a condenser adapted to operate at one pressure and an evaporator adapted to operate at a lower pressure, a U-trap connecting said condenser and said evaporator through which liquid flows from the former to the latter, said U-trap having substantially no resistance to liquid flow and serving to form a liquid column to maintain the pressure diiferential between the evaporator and condenser, the system with which the condenser and evaporator are associated being such that vaporization of liquid in the evaporator is in the nature of boiling as contrasted with the phenomenon of surface evaporation, and said U-trap including a plurality of parallel branches in the up-leg thereof whereby liquid is divided into a plurality of paths of flow in each of which liquid flows upwardly, and said U-trap being so constructed and arranged that vapor forms in said branches to produce vapor blocking to promote distribution of liquid into the several paths of flow.

4,. A multi-pressure absorption refrigeration system having acondenser adapted to operate at one pressure and an evaporator adapted to operate at a lower pressure such that vaporization of liquid therein is in the nature of boiling as contrasted with the phenomenon of surface evaporation, -a U-trap and a flash chamber associated with the evaporator and through which liquid is conducted from the condenser to the evaporator, said flash chamber having a plurality of spaces in vapor communication with the evaporator and from which liquid flows by gravity to different parts of the evaporator, and structure for subdividing liquid flowing from the condenser including a plurality of riser tubes connected in parallel in the up-leg of said U-trap with the upper ends of said tubes being in communication with the spaces in said flash chamber, said structure being so constructed and arranged that the liquid flowing upwardly in said riser tubes has a vapor pressure greater than the vapor pressure in the evaporator whereby vaporization of liquid is effected to produce vapor blocking in said riser tubes to promote dividing of liquid into the latter, and said flash chamber being provided to serve as a region in which vapor flashing may occur to cool the liquid to a temperature corresponding to the vapor pressure in the evaporator without disturbing the dividing of liquid efiected by said riser tubes. 1

5. An absorption refrigeration system in which flow of refrigerant is effected and including an evaporator adapted to operate at such a pressure that vaporization of refrigerant therein is in the nature of boiling as contrasted with the -phe nomenon of surface evaporation, a flash chamber in vapor communication with said evaporator, structure including said flash chamber for subdividing refrigerant flowing in the system into several paths of flow to supply refrigerant to a plurality of parts of the evaporator, said structure being so constructed and arranged that vapor blocking is utilized in said several paths of flow to promote division of liquid therebetween, and said flash chamber being associated with said evaporator and arranged in said refrigerant dividing structure in such a manner that vapor 6. In a refrigeration system in which circ'ula- 2 tion of liquid is effected, such system including a first part and a plurality of places which receive liquid from said first part, the pressure existing in said flrst part being higher than the pressures existing in said places during operation of the system; structure including a plurality of riser tubes connecting said part and said places for dividing and conducting liquid from said part in a plurality of paths of flow to said places, said structure forming a downleg and an up-leg through which the liquid flows to form liquid columns to maintain the pressure differential between said part and said places, said riser tubes having vapor formed therein by heat derived from the liquid as the liquid passesv through progressively lower regions of pressure in said paths of flow, and said structure being so constructed and arranged that said vapor is utilized to retard the rate at which liquid flows into said riser tubes to promote dividing of the liquid between said paths of flow.

7. In an absorption refrigeration system in which circulation of liquid is effected, such system including a condenser and evaporator structure; means including a, plurality ofsriser tubes connecting said condenser and said evaporator structure for dividing and conducting liquid from said condenser in a plurality of paths of flow to different places in said evaporator structure, the pressure existing in said condenser being higher than the pressure existing in said evaporator structure during operation of the system, said connecting means including said riser tubes forming a down-leg and a plurality of up-legs throughwhich the liquid flows to form liquid columns to maintain the pressure differential between said'condenser and said evaporator structure, said riser tubes having vapor formed therein intermittently by sudden vaporization of small amounts of liquid due to the liquid tending to remain in a liquid phase above the boiling temperature while passing upwardly through progressively lower regions of pressure in said riser tubes, and said means being so constructed and arranged that said vapor is utilized to retard the rate at which liquid flows into said riser tubes to promote dividing of the liquid between said paths of flow.

8. A two-pressure absorption refrigeration system of the type which operates in a partial vacuum and having a generator and condenser adapted to operate'at one pressure and an evaporator and an absorber adapted to operate at a lower pressure, and connections fo'rthe aforementioned parts to provide circuits for circulation of refrigerant and absorption liquid, the connection through which liquid is conducted from the condenser to the evaporator including a plurality of parallel branches for supplying liquid to different parts of the evaporator and providing liquid columns to maintain the pressure difierential, said parts and connection being so constructed and arranged that the liquid flowing into said branches has a vapor pressure greater. than the vapor pressure in the evaporator whereby vaporization of liquid takes place in said branches to produce vapor blocking therein to promote division of liquid into the branches. 1

erant and a saline solution as an absorbent, a

generator and condenser adapted to operate at 6 ascents one pressure and an evaporator and absorber adapted to operate at a lower pressure, and connections for the aforementioned parts to provide circuits for circulation of refrigerant; and ab sorption liquid, the connection through which 5 liquidds conducted from the condenser to the evaporator including a plurality of parallel branches for supplying liquid to different parts of the evaporator and providing liquid columns to maintain the pressure difierential, said parts

Images