US3320760A

US3320760A - Rapidly variable capacity absorption refrigeration system

Info

Publication number: US3320760A
Application number: US543749A
Authority: US
Inventors: Judson S Swearingen
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-04-19
Filing date: 1966-04-19
Publication date: 1967-05-23
Anticipated expiration: 1984-05-23

Description

May 23, 1967 J. s. SWEARINGEN RAPIDLY VARIABLE CAPACITY ABSORPTION REFRIGERATION SYSTEM Filed April 19, 1966 wm Wm I I l I II l I I l l I I liillinullnllinl duuso/v S. SWEAR/NGf/V I N VENTOR.

United States Patent 3,320,760 RAPIDILY VARIABLE CAPACITY ABSORPTION REFRIGERATION SYSTEM Judson S. Swearingen, 2235 Carmelina Ave., Los Angeles, Calif. 90064 Filed Apr. 19, 1966, Ser. No. 543,749 Claims. (Cl. 62-141) This invention relates to an absorption refrigeration system and particularly to one in which the output of refrigeration may be changed very rapidly to accommodate rapid variations in requirements for refrigeration.

The system provided by this invention is particularly applicable to absorption refrigeration in which both the absorbent and the refrigerant are liquids at normal pressures and temperature and in which the spent absorbent is separated from the refrigerant by distillation. The invention has special applicability in systems wherein the distillation is carried out in a multiple effect system. However, it is not limited to these specific applications as will hereinafter appear.

In conventional absorption refrigeration systems the refrigeration is generated by evaporation of the refrigerant as it flows over a bank of tubes in an evaporator, and the refrigeration serves to cool the contents of such tubes. The most common arrangement i to provide such tubes and arrange them so as to conduct therethrough a fluid medium such as water, or in the event of a lower temperature requirement, a lower freezing liquid such as brine, so that such fluid medium will be cooled by the refrigeration. The vapor liberated by the evaporation is absorbed by the absorbent liquid as such liquid is introduced into an absorber and is permitted to flow downwardly over another set of coils or bank of tubes through which a cooling medium is normally caused to flow. Both banks of tubes are generally located in the same vessel so that it may be said that the evaporator and the absorber are in free communication with one another. The spent absorbent (spent in that it is partly or completely saturated with refrigerant) drains to the bottom of the vessel and is returned to the regeneration section of the system where it is regenerated by the application of heat resulting in the distillation of the refrigerant content thereof, the refrigerant content thereby passing off as a Vapor and being collected and condensed for reuse.

The most common way of controlling a system of this kind as to the amount of refrigeration which it produces is by controlling the amount of heat applied to the regenerator in which the refrigerant is distilled from the spent absorbent. Controls have also been applied to regulate the rate at which the spent absorbent is returned from the absorber to the regenerator or distillation portion of the system.

In the so-called multiple effect distillation employed in such systems heat is applied to the spent absorbent in a first effect heater while it is under substantially higher pressure than prevails in a second effect condenser. The resulting vapor from this first effect heater where direct heat is applied, condenses in a steam heated still wherein it supplied the heat to further boil the absorbent which is partially regenerated in the first effect heater. In this steam heated still the partially regenerated liquid absorbent is at a substantially reduced pressure so that it will boil under the heating action of the condensing steam. The vapor from the second effect heater condenses in the second effect condenser.

When control of the system is effected by controlling the heat input to the first heating zone there is a great lag in response making the system quite unstable and if the control is effected by a switching on and off of the heating supply, then there is always either overheating or insufficient heating. Control of flow of the spent absorbent requires exactitude of regulation or it likewise will result in insufficient heating or excessive regeneration.

It is therefore an object of this invention to provide a system of absorption refrigeration in which the temperature and the quantity of refrigeration produced are controlled by controls which are immediately responsive and in which the system operates at a high efliciency over a wide capacity range.

Another object is to provide such a system which may be caused to change from a low rate or zero rate of refrigeration production to production of its maximum capacity of refrigeration without any practical time lag.

Another object is to provide such a system in which the spent absorbent is most efficiently regenerated.

Another object is to provide such a system in which the spent absorbent will be efficiently regenerated but in which the rate of regeneration is not required to correspond to the rate of refrigeration at any given time.

Another object is to provide such a system in which the maximum rate of heat input for regeneration may be begun at any time and without any substantial delay.

Another object is to provide such a system in which the heat input will be into a non boiling liquid to provide a favorable heat transfer rate and produce the lowest feasible corrosion rate of the heating vessel.

Another object is to provide such a system in which the temperature to which the absorbent is subjected in the absorber may be precisely regulated'so that it will not reach the freezing point of the absorbent yet will so closely approach such freezing point as to provide the lowest possible temperature in the evaporator and hence provide for the greatest efficiency of heat transfer to a fluid medium being cooled by such refrigeration.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein is set forth by way of illustration and example one embodiment of this invention.

In the drawing:

The single figure is a diagrammatic illustration of an absorption refrigeration system embodying the present invention.

In the embodiment illustrated in the drawing which will be described in more detail hereinafter provisions are made for the storage of substantial quantities of refrigerant in liquid form ready to be introduced into an evaporator for producing refrigeration at such rate as may be required by any demands that may be made upon the system for refrigeration up to the full capacity of the system whether such demands be sudden or gradual, and for the storage of a substantial amount of absorbent fully regenerated and ready for introduction into the absorber to control the pressure and hence the temperature at which refrigeration is produced. The maintenance of such stored quantities of refrigerant and absorbent ready for use not only make possible the immediate meeting of such demands as may be made upon the system, but also render it unnecessary that the rate of regeneration be immediately increased to a rate comparable to that at which refrigeration is demanded. Regeneration may therefore be conducted at a more efficient rate and changes in the rate of refrigeration may be made more gradually.

In the regeneration of absorbent in accordance with this invention the application of external heat is so regulated as to maintain the absorbent in the zone being heated at a constant temperature and this temperature is so regulated as to be sufficiently high to properly regenerate any incoming spent absorbent. The constant temperature so maintained should be low enough so that it will not boil the at least partially regenerated absorbent present therein, but high enough so that when spent absorbent is introduced into such body of partially regenerated absorbent the refrigerant therein will be vaporized and driven off. The body of partially regenerated absorbent in such heating zone will be kept great enough with respect to the maximum expected rate of introduction of unregenerated absorbent that the introduction of such unregenerated absorbent at the maximum expected rate willvnot be sufficient to lower the temperature of the Whole body of absorbent in such regenerating zone to a temperature below the point at which the refrigerant therein will vaporize, for a period of time required for efficient increasing of the rate of heating to compensate for the introduction of the spent absorbent.

The vaporization of refrigerant is preferably carried out in such a way that it acts as a vapor lift type of pump to circulate the hot liquid in the regenerator. The vapor thus produced passes into the disengagement zone along with a proportionate amount of heatedvliquid absorbent substantially half regenerated. The amount of heat applied to the heating zone of the regenerator is controlled automatically by the temperature within such zone to maintain such temperature constant.

By this means a constant temperature is immediately available in the heating zone for initial distillation or partial distillation of spent absorbent entering the heating zone. At the same time, the heat required for distillation is put into a nonboiling liquid which is preferable from the standpoint of heat transfer rate and of minimum corrosion of the heating vessel.

It is desirable that the heat exchangers and the abovementioned heating zone of the regenerator receive the spent absorbent at a gradually increasing rate rather than in a sudden surge when a sharp increase in refrigeration is called for. This is accomplished in the structure shown in the drawing by providing a pumping mechanism for pumping the spent absorbent preferably slowly at first but at an increasing rate from the bottom of the absorber toward the regenera-tor. The rate of pumping is controlled by the accumulationof spent absorbent in the bottom of the absorber so as to be greater when the quantity of absorbent is greater and slower when the quantity of absorbent in the absorber drops.

It is, of course, desirable to have the temperature at which refrigeration is produced in the evaporator as low as possible so as to create as much temperature difference as possible between such evaporator and the fluid medium being circulated in heat exchange relation thereto in order that the heat exchanger costs may be kept as low as possible. On the other hand, this temperature must not be allowed to drop to the freezing point of the absorbent. The temperature is controlled in the illustrated embodiment by controlling the flow of absorbent into the absorber so as to maintain the pressure in the evaporator constant at a predetermined value.

On the other hand, the amount of refrigeration produced may be controlled by increasing or decreasing the flow of refrigerant to the evaporator as the temperature in the fluid medium being circulated in heat exchange relation to the evaporator rises or falls, such regulation be ing preferably of such a nature as to maintain the temperature of such fluid medium leaving the evaporator substantially constant at a predetermined value.

Referring more in detail to the drawing:

A coil 1 is provided for circulating a fluid medium such as water or brine through an evaporator or evaporation zone wherein a spray 2 of liquid refrigerant is released over the coil 1 under pressure conditions low enough to cause evaporation of the refrigerant from the coil surfaces and thereby produce refrigeration, when the temperature of the fluid medium in such coil is above a predetermined value. Because of the heat exchange relation between the fluid in the coil 1 and the refrigerant on the exterior thereof, such refrigerant will take up heat from the fluid medium within the coil and be evaporated thereby resulting in lowering of the temperature of such fluid whereupon it will be Withdrawn as in i t by the arrows on the coil 1 and conducted to a point where it may be used for whatever purpose it was intended. The evaporator is contained within a closed vessel 3 and within this closed vessel preferably somewhat below the evaporator section within which the coil 1 and the spray 2 are located there is a cooling coil 4 through which some type of coolant may be circulated in order to remove some heat from the zone within which the spray 5 introduces a fresh absorbent into the vessel 3. This absorbent will abs-orb the vapor resulting from evaporation of refrigerant from the, spray 2 and the coolant in the coil 4 will serve to remove the heat of absorption. The absorbent having thu-s absorbed the refrigerant vapor will collect in a pool 6 in the lower portion of the vessel 3 from which itmay be withdrawn through a drain pipe 7 by means of a pump 8 and forced through a pipe 9 to heat exchangers 10 and 11 through which it passes successively and in which it will be somewhat warmed through heat exchange with regenerated absorbent as presently to be described. It then passes through the line 12 and into the column 13 in which, in accordance with this invention, there will be maintained a large volume of hot partially regenerated absorbent. The temperature of the partially regenerated absorbent in the column 13 will be maintained sufiiciently high that when the spent absorbent enters the column the refrigerant absorbed therein will boil and be released as refrigerant vapor. This release of vapor which occurs as illustrated far beneath the surface of the liquid in the column 13, will act as a vapor pump within the column 13 and as the vapor rises into the chamber 14 above the column 13 it will carry with it some of the liquid absorbent from the column 13.

In the chamber 14 most of the refrigerant vapor will be disengaged from the liquid absorbent and will flow over through the passageway 15 above the partition between the chambers 14 and 16 and into the chamber 16. The liquid absorbent thus disengaged from the vapor in chamber 14 will flow back into the heater portion of the regenerator' through the conduit 17. It is noted that the upper end of the walls of the column 13 extend somewhat above the bottom of the chamber 14 so that such liquid as falls back into the bottom of the chamber 14 cannot run back into the column 13 but must instead flow through the passageway 17 into the space in which heat is being added from the outside as will be presently described.

A small portion of the liquid entering the chamber of the chamber 16. The partially regenerated liquid will not be permitted to excessively accumulatein the chamber 16. This quantity is controlled asvby a float operated valve 18 whereby the liquid will be permitted to flow out as fast as it comes into the chamber 16. It will flow out through the line 19 into the heat exchanger 11 wherein it will flow countercurrently with respect to the spent absorbent passing through this heat exchanger as hereinbefore described and will serve to heat the spent absorbent in the course of such passage while this liquid from chamber 16 still remains at very nearly the pressure prevailing in chamber 16. The partially regenerated, partially cooled absorbent will then leave the heat exchanger 11 through a line 20, in which the valve 18 is located, and pass through a coil 21 and int-o a chamber 22. Having beencooled in exchanger 11 this liquid from chamber 16 will not boil significantly under the very considerable pressure reduction which it undergoes in passing through valve 18. However, it will, as a result of such pressure reduction be in condition to be boiled by the heat from the first effect vapor which will contact coil 21 and be condensed thereon in chamher 27 as it provides second effect heat to the absorbent in coil 21. The vapor space in the chamber 22 communicates through a passage 23 above a partition between the chamber 22 and the chamber 24 and in the chamber 24 there is located a cooling coil 25 through which cooling water or other cooling medium is caused to flow. The cooling thus produced by the cooling coil 25 will serve to maintain by condensation of refrigerant vapor the partial pressure of any refrigerant vapor in the chamber 24 and thus the pressure therein and therefore that in the chamber 22 and the inside of the coil 21 will be quite low. Such vapor will have been liberated from fully regenerated absorbent so the absorbent, which has an affinity for the refrigerant vapor, must necessarily have been at a much higher temperature than condensing refrigerant at the same pressure.

Referring again to the chamber 16 wherein the refriger-ant vapor produced in column 13 is fully disengaged from liquid, the vapor, still at the high pressure prevailing in chamber 16, passes therefrom through a passage 26 over the partition between the chamber 16 and a chamber 27, and into chamber 27 wherein the coil 21 is located. The coil 21, having partially cooled regenerated absorbent flowing inside of it at the relatively lower pressure to which it was reduced by the valve 18, is the only heat absorbing element in the vapor space communicating with the chamber 16. Refrigerant vapor continually rises into the chamber 16 and increases the pressure therein until it is sufficiently high that it will condense at the temperature of the outside of the coil 21, thereby heating the partially regenerated absorbent in the coil 21 while the refrigerant vapor condenses on the outside surface of this coil while the partially regenerated liquid inside the coil boils.

Liquid thus condensing on the coil 21 will fall to the bottom of the chamber 27 and flow out through the line 28 into the chamber 24 where it will join the condensed refrigerant which will have condensed on the coil 25 in that chamber.

The pressure in the chamber 27 and the chamber 16 being much higher than that in chamber 22 for reasons heretofore stated, the partially regenerated liquid absorbent in the bottom of the chamber 16 will flow through the valve 18 when the same is opened, having freely reached it through heat exchanger 11 it then flows through line 20. The pressure downstream from the valve 18 will be only slightly above that prevailing in the chamber 22, differing therefrom only by the amount of the pressure drop through the coil 21.

The partially regenerate-d absorbent inside of the coil 21 will thus freely boil and liberate the remainder of the absorbed refrigerant as the vapor condenses on the outside of this coil. Thus the absorbent within the coil becomes fully regenerated but with some refrigerant vapor entrained therein and this mixture of liquid and vapor is discharged into chamber 22 wherein the vapor is fully disengaged and flows through the pasage 23 into the chamber 24 to condense on the surface of the condenser coil 25. Thereafter it falls and accumulates in the bottom of the chamber 24. The fully regenerated absorbent will accumulate in the bottom of the chamber 22.

As refrigeration is required, refrigerant will flow out of chamber 24 through the line 29 and into the sprays 2 from which it is distributed on the outer surfaces of the evaporator coil 1 to cool the water or other fluid medium circulating therein. The refrigeration requirement is normally determined by the temperature of the circulating medium such as water within the coil 1. A temperature sensing element 30 is located in temperature sensing relation to the outflow from coil 1 and connected to control the valve 31 which in turn controls the flow of refrigerant from the chamber 24 onto the evaporator coil 1. As refrigerant evaporates on the outer surfaces of the coil 1 vapor in large volume is formed inside the chamber 3 thereby increasing the pressure inside of chamber 3. Since pressures for control purposes.

the pressure inside of chamber 3 determines the temperature at which vaporization of refrigerant will take place, the refrigerant vapor thus formed must be removed in order to keep the evaporator temperature down to the point desired. To accomplish this absorbent is delivered from the chamber 22 through a line 32, through heat exchanger 10 wherein it countercurrently heats spent absorbent from the evaporator chamber 3 and is itself cooled. The heat exchanger 10 has a relatively large mass and heat capacity so that flow of countercurrent streams therein need not be simultaneous. This cool regenerated absorbent then flows through the line 33 and through sprays 5 onto the outer surfaces of the cooling coil 4. On such surfaces it is exposed to the refrigerant vapor inside the chamber 3 and absorbs the vapor, thereby keeping the pressure inside of chamber 3 lower than it otherwise would be. The regenerated absorbent becomes spent by this absorption and falls to the bottom of the chamber 3.

The rate of flow of regenerated absorbent onto the coils 4 necessary to maintain the predetermined desired low pressure and hence a predetermined temperature of refrigeration on the coil 1, is controlled by the valve 34 which in turn is controlled by a pressure sensing element 35 exposed to the pressure within the evaporator chamber 3. The sensor 35 and the valve 34 are so adjusted that when the pressure within the evaporator chamber 3 tends to rise and this is sensed by the sensor 35, the valve 34 will open to permit more absorbent to flow through the spray 5, thereby reducing such pressure. These will be set to keep the pressure within the chamber 3 at a substantially constant predetermined value so as to maintain the temperature on the coil 1 at substantially constant predetermined value. This temperature should be determined by making it as low as possible while keeping it above the freezing point of the refrigerant. In case of the use of water as a refrigerant, which is frequently done, the temperature should be some 3 or 4 degrees above that of the freezing point of water, or approximately 36 or 37 degrees Fahrenheit. The vapor pressure of water of 32 degrees Fahrenheit being 4.6 millimeters of mercury absolute and that at 37 degrees being 5.6 millimeters, this relatively low temperature difierential above the freezing point of water will provide a very satisfactory ratio of It will be understood, however, that the system is not limited to the use of water as a refrigerant as some other substances, well known as refrigerants may be employed, along with substances respectively suitable as absorbents therefor. However, when water is used as a refrigerant a suitable absorbent is lithium bromide solution in water in concentration between 58% and 64%, by weight, with a variation between 4% and 5% between spent and regenerated condition. Thus when spent the percentage of lithium bromide might, for example, be 58% and when regenerated 62%.

In the event of the use of refrigerant and absorbent from the stored up supplies in

chambers

24 and 22 at a temporarily very high rate and one higher than the current rate of regeneration of absorbent, the levels in

chambers

22 and 24 will begin to drop and a substantial quantity of spent absorbent will begin to accumulate in the bottom of the chamber 3 at a correspondingly high rate. As the level of this spent absorbent rises in the bottom of chamber 3 it Will actuate the float in that chamber and cause the pump 8 to begin building up its rate of pumping and within a time of the order of a minute or two the systern should be able to deliver regenerated absorbent and condensed refrigerant into the

storage chambers

22 and 24 at substantially the rate of withdrawal therefrom. Meanwhile, however, the sudden requirement for refrigeration will have been met without delay. The inventories in chambers '22 and 24 should be sufficient to last for a time sufiicient for the regeneration to catch up to the rate of usage, which will of course vary according to the design of and requirements from the system. Normally a one or two minute supply in chambers '22 and 24 for the highest expected rate of use should be sufficient.

One of the reasons why the system thus described can fairly quickly begin to deliver regenerated streams to the

respective chambers

22 and 24 is found in the heating furnace 36. This furnace consists of an outer shell 37 with an inner heating surface 38 heated by hot gases passing therethrough and originating in the burner 39. The annular space 40 between the outer shell 37 and the heating surface 38 is maintained full of partially regenerated absorbent liquid. This space is connected through communicating lateral conduits 41 and 42 with a large vertical column 13 previously mentioned which is likewise filled with the same body of hot partially regenerated absorbent liquid. These large passageways 41 and 42 permit free thermal convection or temperature induced flow between the column 13 and the annular space 40 so that these remain at substantially the same temperature and this temperature is determined by the setting of the temperature controller 43 as biased by a pressure controller 43a exposed within the chamber 14, which actuates a valve 44 in the fuel line to the burner 39. The reason for the pressure controller 43a arises out of the fact that under varying conditions of operation the pressure in chambers 14 and 16 and hence that at any. point Within the body of liquid in furnace 36 varies. Hence, if the temperature were maintained constant without reference to such pressure, the constituency of this body of liquid would vary with variations in pressure. Since it is desirable to keep this constituency the controller 43a is provided to suitably bias the temperature controller 43 to compensate for pressure variations. By these means the temperature of the liquid in the annular space and in the column 13 ismaintained at a desired constant temperature subject however to bias to correct for pressure variations .and consequently at a desired concentration.

When liquid accumulates in the bottom of the shell 3 and is delivered by the pump 8 to the column 13 well below the surface. of the liquid the spent absorbent so delivered boils at a lower temperature than that of the partially regenerated absorbent in the column-13 and upon entering immediately flashes and liberates its equivalent portion of absorbed refrigerant as vapor in the form of bubbles which rise upward in column 13. This causes rapid upflow in column 13 and increases the rate of circulation through passageways 41 and 42 and the annulus '40 and improves the heat transfer rate on the heating surface 38.

The heater thus described has the advantage of self circulation, of being immediately ready to deliver any reasonably required quantity of heat to the incoming spent absorbent, and of receiving the heat from the surface 38 without boiling.

It is possible for small amounts of fixed gas to get into the chamber 3 by small leaks or through chemical action such as corrosion which liberate fixed gas. This interferes with the rate of absorption of refrigerated vapor on the surface of the coil 4 and such gas must be removed. A convection barrier 45 is employed to partition off a zone inside of the chamber 3 which includes a portion of the absorbing surface on the coil 4 and because of the absorption of vapor inside of the zone created by the barrier 45 there will be a flow of vapor into that chamber. This flow is so arranged that it sweeps all of the coils 4 which are not inside of the zone and thereby sweeps away any gas in their vicinity away from such coils and into the aforesaid zone. Gas collected in such zone flows along with the absorbent 6 into the pump 8 and eventually passes over into the chamber 27 along with the vapor from the first effect heating and in this chamber such vapor is condensed on the surface of coil 21.

A similar convection barrier 46 is placed inside the chamber 27 to form an enclosed zone in the upper part thereof which contains a portion of the condensing surface of the coil 21. This acts to draw a portion of the vapor coming into the chamber 27 across the unenclosed portion of the coil 21 and this sweeps any fixed gases off of that surface and through the barrier along with the vapor which may condense on the portion of the coil 21 which is inside of the enclosed zone. Thus all of the fixed gas will be brought into the zone above the barrier 46 from which it may be withdrawn through a line 47. with a small portion of the refrigerant vapor. It is drawn from the line 47 by a vacuum pump 48 and rejected to the atmosphere but the line 47 is provided in its vertical portion with air cooling fins 49 or other similar devices which serve to radiate heat and cause condensation therewithin of most of the refrigerant vapor, which then flows back by gravity into the chamber 27.

The requirements of systems such as described are such that the boiling pressure in chambers 14, 16 and 27 when using water as a refrigerant are of the order of 5 to 20 pounds per square inch absolute. The vacuum pump 48, therefore, must have the characteristic of pumping against a negative as well as a positive head so as to prevent excessive quantities of vapor from leaving the system should the pressure inside of the chamber 27 be above atmospheric pressure.

From the foregoing it will be seen that that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the method.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood thatall matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

1. In an absorption refrigeration system which comprises a regenerated absorbent reservoir, a regenerated liquid refrigerant reservoir, an evaporator and absorber in open communication with one another, first and second conduit means connecting said refrigerant. reservoir to said evaporator and said absorbent reservoir to said absorber, respectively, a regenerator, third conduit means connecting said absorber to said regenerator to conduct spent absorbent to said regenerator, and means connected to said regenerator for receiving absorbent and refrigerant from said regenerator and separating and cooling same and delivering them to said reservoirs respectively, the improvement which comprises an automatic flow controller in one of said first and second conduit means having a sensing control element exposed to a portion of the interior of the system affected by the refrigeration produced in the evaporator for sensing a condition in said portion significant of the refrigeration produced in said evaporator, whereby flow of one of said absorbent and refrigerant to said intercommunicating evaporator and absorber may be controlled by said condition to thereby control the refrigeration produced in said evaporator and maintain said condition within predetermined desired values.

2. An absorption refrigeration system as set forth in claim 1 in which said flow controller is in-the conduit between the absorbent reservoir and the absorber and said sensing control element is a pressure sensing element located to sense the pressure in said evaporator.

3. An absorption refrigeration system as set forth in claim 1 in which there is a fluid medium circulating means in heat exchange relation to said evaporator to cool such of said fluid medium emerging from said heat exchange relation with said evaporator.

4. An absorption refrigeration system as set forth in claim 1 in which the regenerator comprises a vessel adapted to contain absorbent, means for applying heat to a body of absorbent in said vessel at a rate to maintain its temperature within a range below the boiling point of the absorbent and above the boiling point of the refrigerant being used.

5. An absorption refrigeration system as set forth in claim 4 in combination with means for adjusting said rate of applying heat so as to maintain said temperature within said range during the highest expected rate of addition of spent absorbent to said regenerator.

6. An absorption refrigeration system as set forth in claim 5 in which said means for adjusting the rate of applying heat includes a temperature sensor exposed to the absorbent adjacent the point of introduction of spent absorbent into said regenerator and adapted to increase the rate of heat addition when temperature at such point falls below a predetermined minimum and decrease the rate of heat addition when the temperature at such point exceeds a predetermined maximum.

7. An absorption refrigeration system as set forth in claim 4 in which the absorbent capacity of said regenerator relative to the greatest expected surge of spent absorbent thereto and the time required for increased application of heat from the minimum to the maximum rate is sufiiciently large that the largest anticipated surge of spent absorbent entering into said regenerator when the same is full of partly regenerated absorbent at a temperature just below its boiling point will not result in lowering the temperature of the resultant body of absorbent below the boiling point of the refrigerant within the regenerator within the time required for the maximum rate of application of heat to the regenerator to begin.

8. An absorption refrigeration system as set forth in claim 4 in which said regenerator has a portion normally filled with hot liquid absorbent and said portion is shaped to provide a circulating path for such absorbent, and in which said means for applying heat is located to apply it to a portion of said circulating path.

9. An absorption refrigeration system as set forth in claim 5 in which the point of introduction of spent absorbent into said regenerator is below the normal level of liquid absorbent in said regenerator.

10. An absorption refrigeration system as set forth in claim 9 in which said regenerator has a portion normally filled with hot liquid absorbent and shaped to provide a circulating path therefor, said means for applying heat is positioned to apply it to a portion of said path, and in which the point of introduction of spent absorbent into said regenerator is in a portion of said circulating path remote from the portion to which said heat is applied.

References Cited by the Examiner UNITED STATES PATENTS 2,650,480 9/1953 Gilmore 6214l X LLOYD L. KING, Primary Examiner.

Claims

1. IN AN ABSORPTION REFRIGERATION SYSTEM WHICH COMPRISES A REGENERATED ABSORBENT RESERVOIR, A REGENERATED LIQUID REFRIGERANT RESERVOIR, AN EVAPORATOR AND ABSORBER IN OPEN COMMUNICATION WITH ONE ANOTHER, FIRST AND SECOND CONDUIT MEANS CONNECTING SAID REFRIGERANT RESERVOIR TO SAID EVAPORATOR AND SAID ABSORBENT RESERVOIR TO SAID ABSORBER, RESPECTIVELY, A REGENERATOR, THIRD CONDUIT MEANS CONNECTING SAID ABSORBER TO SAID REGENERATOR TO CONDUCT SPENT ABSORBENT TO SAID REGENERATOR, AND MEANS CONNECTED TO SAID REGENERATOR FOR RECEIVING ABSORBENT AND REFRIGERANT FROM SAID REGENERATOR AND SEPARATING AND COOLING SAME AND DELIVERING THEM TO SAID RESERVOIRS RESPECTIVELY, THE IMPROVEMENT WHICH COMPRISES AN AUTOMATIC FLOW CONTROLLER IN ONE OF SAID FIRST AND SECOND CONDUCT MEANS HAVING A SENSING CONTROL ELEMENT EXPOSED TO A PORTION OF THE INTERIOR OF THE SYSTEM AFFECTED BY THE REFRIGERATION PRODUCED IN THE EVAPORATOR FOR SENSING A CONDITION IN SAID PORTION SIGNIFICANT OF THE REFRIGERATION PRODUCED IN SAID EVAPORATOR, WHEREBY FLOW OF ONE OF SAID ABSORBENT AND REFRIGERANT TO SAID INTERCOMMUNICATING EVAPORATOR AND ABSORBER MAY BE CONTROLLED BY SAID CONDITION TO THEREBY CONTROL THE REFRIGERATION PRODUCED IN SAID EVAPORATOR AND MAINTAIN SAID CONDITION WITHIN PREDETERMINED DESIRED VALUES.