US2297280A

US2297280A - Refrigeration

Info

Publication number: US2297280A
Application number: US220203A
Authority: US
Inventors: Justice H Beach
Original assignee: Hoover Co
Current assignee: Hoover Co
Priority date: 1938-07-20
Filing date: 1938-07-20
Publication date: 1942-09-29
Anticipated expiration: 1959-09-29

Description

Sept. 29, 1942. BEACH 2,297,280

REFRIGERATION Filed July 20, 1958 F 26' I M l i i i i 1 i i i i i B H z? INVENTOR Juslice b. fleac/z BY 5 w x z ATTORNEY v Patented Sept. 29, 1942 REFRIGERATION Justice H. Beach, Canton, Ohio, assignor to The Hoover Company, North Canton, Ohio, a corporation of Ohio Application July 20, 1938, Serial No. 220,203

23 Claims.

This invention relates to the art of refrigeration and more particularly to a novel absorption refrigerating system of the three-fluid type utilizing a power driven element to circulate a pressure equalizing medium.

Heretofore, refrigerating systems of the threefluid absorption type utilizing a power driven element to circulatethe inert gas have been difiicult to design to meet the rigid space limitations imposed by domestic refrigerating cabinets because of the differential of pressure existing in diiferent parts of the system due to the power driven circulator. Though this pressure is small, of the order of a few inches of water as compared to a total system pressure of several hundred pounds, nevertheless it requires an increase in the height of the system in order to provide balancing liquid columns in various portions thereof for the fan pressure or it necessitates the use of various liquid seals and venting devices between the condenser and the evaporator of suchsystems which increases the complexity thereof.

According to the present invention there is provided a three-fluid absorption refrigerating system of the type utilizing a power driven fan to circulate the inert gas which is arranged with the power driven circulator in the rich gas conduit contrary to the usual practice, and which is also arranged in such fashion that the analyzer is subjected to the discharge pressure of the fan and no liquid seals or venting means are necessitated between the condenser and evaporator.

According to the present invention there is provided a refrigerating system in which a non-submerged plate type analyzer, having an appreciable vertical extent, may be utilized with the system without unduly increasing the over-all height of the system and which is so constructed and arranged that the analyzer inlet may actually extend above the bottom portion of the absorber.

Other objects and advantages of the invention will become apparent as the description proceeds when taken in connection with the accompanying drawing, in which:

Figure 1 is a diagrammatic representation of one form of the invention, and

Figure 2 is a diagrammatic fragmentary view of a modified form ofthe invention.

Referring now to the drawing in detail and first to Figure 1, there is disclosed a'three-fluid absorption refrigerating system comprising a boiler 13, an analyzer D, an air-cooled rectifier R, a tubular air-cooled condenser C, an evaporator E,-

a gas heat exchanger G, an absorber A, a liquid heat exchanger L, a, solution reservoir S, and a 55 circulating fan F which is driven by a suitable electrical motor M. The above described elements are inter-connected by various conduits to form a plurality of gas and liquid circuits constituting a complete refrigerating system-to which reference will be made in detail hereinafter.

The above described refrigerating system will be charged with a suitable refrigerant, such as ammonia, a suitable pressure equalizing medium, such as nitrogen, and a suitable absorbent, such as water.

The boiler B may be heated in any suitable manner as by a'g'as'burner'H. The gas burner H and the motor M are controlled by any desired type of control mechanism which will regulate the energization of the refrigerating system in accordance with refrigeration demand.

The application of heat to the .boiler B generates refrigerant vapor from the strong solution therein contained. The vapor then passes upwardly through the perforated'plates [2 in the analyzer D and in counterflow relationship to strong solution which is flowing downwardly through the analyzer over the plates l2. Further refrigerant vapor is generated in the analyzer by the heat of condensation of absorption solution vapor generated in the boiler. The refrigerantvapor is conducted from the upper portion of the analyzer D to the upper portion of the condenser C by'a conduit M which includes the air-cooled rectifier R. Any vapor of absorption solution which may pass through the analyzer D is condensed in'the rectifier and is returned to the boiler-analyzer system through the conduit H. The refrigerant vapor supplied to the condenser is liquified therein by heat exchange with atmospheric air and is discharged from the bottom portion of the condenser through a conduit it which opens into an inert gas supply conduit l6 which is connected to the bottom portion of the evaporator E.

The pressure equalizing medium is placed under pressure by the circulating'fan F and is conducted from the discharge outlet thereof through a finned air-cooled conduit 20 to the bottom portion of the absorber A throughwhich it flows upwardly in counterfiow relationship to absorption solution flowing downwardly through the absorber. The manner in which the absorption solution is supplied to the absorber will be described in detail hereinafter.

The absorber A has been illustrated as extending vertically for purposes of convenience. The absorber may lie in any plane from the vertical to a plane slightly inclined to the horizontal which is the preferred arrangement because of the small vertical space occupied by an absorber in this position.

The refrigerant vapor content of the pressure equalizing medium refrigerant vapor mixture is absorbed by the solution in the absorber and the heat of absorption is rejected to the surrounding air by the cooling fins provided on the exterior walls of the absorber vessel. The lean pressure equalizing medium formed in the absorber is conducted therefrom through a conduit 2|, the outer path of the gas heat exchanger G, and the conduit l6 into the bottom portion of the evaporator E.

The evaporator E is constructed of relatively small diameter tubing whereby the pressure equalizing medium travels therethrough with a velocity sufficient to sweep or drag the liquid refrigerant upwardly through the evaporator as it is evaporating into the pressure equalizing medium to produce refrigeration. By reason of this phenomena the condenser C mayextend substantially to the level of the bottom portion of the evaporator. A full explanation of the mannerin which the liquid refrigerant is circulated through the evaporator will be found in the co-pending application of Curtis C. Coons and William H. Kitto, Serial No. 386,395 filed April 2, 1941. The evaporator illustrated herein is of course diagrammatic only; any suitable form and arrangement of coil structure may be utilized, preferably one which is adapted to form a plurality of shelves to support ice freezing trays and which may be enclosed in a suitable casing structure.

The pressure equalizing medium and unevaporated liquid refrigerant and any foreign material which may find its way into the evaporator flow into a larger diameter box-cooling conduit 23 which is provided with suitable heat transfer fins. The velocity of the pressure equalizing medium through the larger diameter conduit 23 is much less than that prevailing in the evaporator E, Wherefore there is no propelling action on the liquid by the gas. The liquid simply flows through the slightly inclined conduit 23 under the influence of gravity as it is evaporating into the pressure equalizing medium. The rich mixture formed in the evaporator is conducted from the upper portion thereof through a conduit 24 into the inner path of the gas heat exchanger G from which the gas flows through a conduit 25 and a conduit 26 into the suction inlet of the circulating fan F, thus completing the pressure equalizing medium circuit.

The lean solution formed in the boiler B by the generation of refrigerant vapor is conveyed therefrom through a conduit 21, the inner path of the liquid heat exchanger L, and a conduit 28 into the solution reservoir S. The top portion of the reservoir S is vented to the suction conduit 26 of the fan F by a conduit 29. The lean solution is conveyed from the reservoir S through a U- shaped conduit 38 which opens into a rising gas lift conduit 3|. The conduit 31 opens into a downwardly extending portion of the conduit 25 which terminates in a downwardly extending reduced diameter extension 32. The bottom portion of the extension '32 is connected to a conduit 33 which turns upwardly from its point of connection with the conduit 32 and opens into the upper end of the absorber A. It is apparent that the elevation of the points of connection between the conduits 25 and 3| is materially above the liquid level prevailing in the reservoir wherefore some means must be provided to elevate the solution into the conduit 25. For this purpose a small bleed conduit 35 is connected between the discharge conduit 20 of the circulating fan F and the gas lift conduit 3| below the liquid level normally prevailing in the reservoir, whereby the solution is elevated into the vessel 25 by gas lift action.

The absorption solution discharged through the

conduits

32 and 33 flows downwardly through the absorber A in counterfiow to the pressure equalizing medium to the bottom of the absorber from which point it is returned to the analyzer D through a conduit 36, the outer path of the liquid heat exchanger L, and a conduit 31 which opens into the upper portion of the analyzer D. The evaporator E is provided with a drain 38 which opens into the strong solution return conduit 36. The drain 30 opens into the top portion of the lowest evaporator conduit.

The operation of this form of the invention will now be described. The circulating fan F will generate a positive pressure in the pressure equalizing medium of a few inches of water, for example approximately 4 /2" of water. With the arrangement herein disclosed the analyzer is subjected to the pressure prevailing in the conduit 26 minus the pressure represented by the difference in elevation of the liquid levels in the

conduits

36 and 31 by reason of the fact that the conduit 36 opens directly into the discharge conduit 26 of the circulating fan. Likewise substantially the entire fan pressure is borne by the analyzer minus, however, the pressure drop induced in the gas stream as it flows through the absorber, the conduit 21, the outer path of the gas heat exchanger G, and the conduit Hi to its point of connection with the conduit l5, as Well as a slight pressure drop through the conduit 15, the condenser C, and the conduit M. The pressure drop between the conduits 20 and I3 may, for example, be 1% of water, and the pressure drop between the top portion of the analyzer and the conduit l5 may, for example, be of water. From these figures it is evident that the pressure prevailing within the analyzer will be 3 /2" of water above the suction pressure of the circulating fan and the pressure on the conduit 36 will be 4 /2 of water above the suction pressure of the circulating fan whereby the height of the liquid column in the conduit 31 will be approximately 1" greater than the height of the liquid column in the conduit 36. By reason of this arrangement the inlet of the conduit 31 into the analyzer D may extend to a height substantially 1 above the lowest point of the absorber A, though it has been shown herein as extending to substantially the same elevation.

The reservoir S is connected directly into the suction conduit, of the circulating fan whereby the pressure within the reservoir will be approximately 3 /2 of water less than the pressure prevailing in the analyzer. Consequently, the liquid level prevailing in the reservoir will be approximately 3 higher than the liquid level prevailing in the boiler-analyzer system. The above figures are given by way of example only and are not limiting in any sense as the various pressures will vary with varying designs of particular elements of the system and with different refrigerants and absorbents.

This arrangement possesses a number of advantages. Due to the fact that the boiler-analyzer and reservoir system are connected directly intov one side or the other of the circulating fan which operates at constant speed,

the liquid levels in these systems are relatively very stable.

The point at which the gas lift pump 3| discharges into the conduit is subjected to the full suction pressure of the fan and the point at which the conduit 33 opens into the upper end of the absorber A is subjected to the full discharge pressure of the fan minus the pressure drop through the absorber, wherefore the reservoir and U-shaped liquid column pressure balancing system comprising the

conduits

32 and 33 and the lower portion of the conduits and 25 is provided. The liquid stands in the

conduit system

25, 32 to a level above the point of connection between the absorber and the conduit 33 a distance equal to the pressure differential between the conduits 25 and 2|. The inert gas flowing through the pump flows directly into the conduit 26.

As a result of this arrangement of parts, the boiler-analyzer, condenser and evaporator are in free, open and direct communication without the intervention of any liquid seals. This means that the pressure'in the evaporator inlet, condenser, rectifier and boiler-analyzer system is substantially equal wherefore no liquid columns are necessitated between the condenser and the evaporator and the condenser vents into the inert gas circulating through the evaporator directly through the normal condenser evaporator connection. The elimination of the expensive and complex liquid column and venting mechanisms for the condenser greatly simplifies the system.

By subjecting the analyzer to the high pressure discharge side of the fan, the liquid level in the boiler-analyzer system is depressed by this pressure which permits the entire boileranalyzer system to be raised to a level at which the analyzer inlet may even be above the outlet point of the absorber without fear of flooding the gas and liquid contact plates in the analyzer. This also permits a very extensive non-submerged type analyzer to be used which is the most efiicient and serviceable type of analyzer known to the art.

The weak solution side of the solution circuit is subjected directly to the suction pressure of the circulating fan which raises the liquid level in that part of the system. The pressure differential existing between the various parts of the solution circuit is balanced by a column of liquid equal to that pressure differential and represented by the difference of level of the liquid standing in the reservoir S and in the boileranalyzer system. The liquid column interposed between the discharge conduit of the gas lift pump 3| and the absorber solution inlet also balances the pressure differential existing between the absorber outlet and the solution reservoir.

In the form of the invention disclosed in Figure 1, the gas lift pump is operated by rich gas taken directly from the discharge outlet of the circulating fan in order that the maximum possible pressure differential may be had between the gas inlet and the discharge outlet portions of the gas lift pump with resulting increase of possible elevating height of the pump and efficient operation thereof. However, it is more desirable to utilize lean gas to operate the vapor lift pump because the lean gas has a greater density when nitrogen or a similar gas is utilized as the pressure equalizing medium. The system disclosed in Figure 2 is substantially identical with that disclosed in Figure 1 except that it is modified to permit the utilization of lean gas to circulate the lean solution. The disclosure of Figure 2 does not include the entire refrigerating system, the system as a whole is identical with that disclosed in Figure 1 with the exception of certain modifications to a portion of the circuits which are fully disclosed in Figure 2. Certain portions of the apparatus disclosed in Figure 2 are identical with portions of the apparatus disclosed in Figure 1 and are given the same reference characters primed.

In this form of the invention the conduit 25' discharging from the inner path of the gas heat exchanger opens directly into a conduit 26 which supplies the rich mixture to the suction inlet of the circulating fan F. However, the conduit 25 does not continue downwardly below its point of connection with the conduit 26 in the manner in which the conduit 25 continues below the conduit 26. A relatively large diameter conduit 50 opens into the conduit 25 slightly above its point of connection with the conduit 26 and extends downwardly below the point of connection between the lean gas conduit 2| and the outlet of the absorber A". The bottom portion of the conduit 50 joins a conduit 5| which turns upwardly from its point of connection with the conduit 50 and opens into the outlet portion of the absorber A. A small bleed conduit 52 is connected between the lean gas conduit 2| and the gas lift pump 3| below the liquid level normally prevailing in the reservoir S whereby to elevate the weak solution through the gas lift pump 3| into the conduit 50. The gas travelling through the gas lift pump 3| then passes through the conduit 50 into the conduit 25 from which it returnsto the circulating fan F. The liquid discharged through the gas lift pump collects in the lower portion of the conduit 50 and in the conduit 5| forming a liquid column balancing the pressure differential between the conduits 25' and 2| which is necessary because the conduit 25 is subjected substantially to the suction pressure of the circulating fan whereas the conduit 2| is subjected to the full discharge pressure of the circulating fan minus, of course, the pressure drop which occurs in the conduits 2B and in the absorber A.

This form of the invention operates exactly in the same manner in which the form previously described operates and has the same advantages. This form of the invention, however, has the additional advantage that the gas lift pump is now operated by lean gas whereby there is substantially no tendency for absorption to occur in that pump to interfere with its pumping action, and the lean gas possesses a greater density than the rich gas which improves the pumping operation.

There is another distinction between the two forms of the invention disclosed as follows: In the apparatus of Figure l the gas lift pump is operated by the full discharge pressure of the circulating fan regardless of the distribution of the pressure drop throughout the inert gas circulating system whereby the discharge pressure of the circulating fan is utilized in producing flow. By reason of this construction the designer is relatively free to apportion the resistances of the absorber, gas heat exchanger, evaporator and various conduits forming the inert gas circuit without fear of interfering in any fashion with th operation of the gas lift pump. By reason of this construction, a high resistance absorber, such as that disclosed in the co-pending application of Rudolph S. Nelson and Curtis C. Coons, Serial No. 94,932, filed August 8th, 1936, Patent No. 2,196,707, may be utilized in the absorber without fear that the pressure drop through the absorber will interfere in any fashion with the gas lift pump. On the other hand, if a high resistance absorber is used in the construction disclosed in Figure 2, the resistance thereof may be sufficient to lower the pressure in the conduit 2| to a value such that reliable operation of the gas lift pump could not be assured. However, the structure disclosed in Figure 2 is well adapted for utilization with a low resistance absorber, such as that disclosed in the co-pending application of William H. Kitto, Serial No. 206,143, filed May th, 1938.

Attention is called to the fact that it is desirable to charge the system in such manner as to flood the liquid seal provided by

conduits

32 and 33 so as to facilitate starting of the apparatus initially. Accordingly, I have shown a charging device 39 of any conventional type as being conveniently located in the vertical portion of conduit 2| of the preferred form of the apparatus. The fluids are charged into the apparatus in a well known manner, and it will be apparent that a part of the liquid portion of the charge will fill the liquid seal and that the remainder merely overflows into the lower part of the apparatus.

According to the present invention there is provided a three-fluid absorption refrigerating system of the type utilizing a power driven circulator for the inert gas circuit in which the evaporator, condenser and analyzer are in free and open communication without the intervention of sealing devices of any type and which permits a very compact boiler-analyzer-absorber assembly to be utilized. Due to the fact that different portions of the solution circuit are connected directly across the inlet and outlet portions of the circulating fan which operates at constant speed and produces a constant pressure differential, there will be no substantial fluctuation of liquid levels in the solution circuit regardless of transient conditions occurring at various parts of the refrigerating system which might otherwise tend to introduce disturbing conditions in the solution circuit.

The discharge pressure of the circulating fan prevails in the boiler-analyzer, condenser, evaporator system and is utilized to depress the liquid level in the boiler-anlayzer system to permit the use.of a compact boiler and non-submerged analyzer situated at a relatively high elevation in the system. The compactness of the system is further enhanced because of the fact that the pressure prevailing on the absorber side of the strong solution circuit is higher than the analyzer pressure which permits the strong solution inlet to the analyzer to be placed above or level with the bottom portion of the absorber.

The compactness of the system is further improved because the weak solution line is subjected to the suction pressure of the circulating fan. The pressure differential between the weak solution reservoir and the analyzer is balanced by the difference in elevation of the free surfaces of the liquid in these vessels. Thus, the reservoir is raised above the boiler to a position in which it serves to prevent minor system disturbances from affecting the liquid head on the gas lift While the invention has been illustrated and described herein in considerable detail, it is ,not

to be limited to the constructional details illustrated and described. Various changes in construction, arrangement and proportion of the parts may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. Absorption refrigerating apparatus comprising a pressure equalizing medium circuit including an evaporator and an absorber, a solution circuit including a boiler-analyzer and said absorber, a condenser in free unobstructed communication with said analyzer and said evaporator, and a power driven circulator positioned in the rich mixture portion of the pressure equalizing medium circuit to discharge the rich mixture under pressure into said absorber and to circulate the pressure equalizing medium through said evaporator with a velocity suflicient to propel the liquid refrigerant through the evaporator.

2. Absorption refrigerating apparatus comprising a pressure equalizing medium circuit including an evaporator and an absorber, a solution circuit including a boiler-analyzer and said absorber, a condenser in free unobstructed communication with said analyzer and said evaporator, a power driven circulator positioned in the rich mixture portion of the pressure equalizing medium circuit to discharge the rich mixture under pressure into said absorber and to circulate the pressure equalizing medium through said evaporator with a velocity suflicient to propel the liquid refrigerant through the evaporator, a reservoir in the weak solution portion of the solution circuit, a gas lift pump connected to convey liquid from said reservoir into said absorber, and means venting said reservoir to a low pressure area of said pressure equalizing medium circuit.

3. Absorption refrigerating apparatus comprising a pressure equalizing medium circuit including an evaporator and an absorber, a solution circuit including a boiler-analyzer and said absorber, a condenser in free unobstructed communication with said analyzer and said evaporator, a power driven circulator positioned in the rich mixture portion of the pressure equalizing medium circuit to discharge the rich mixture under pressure into said absorber and to circulate the pressure equalizing medium through said evaporator with a velocity sufficient to propel the liquid refrigerant through the evaporator, a reservoir in the weak solution portion of the solution circuit, means venting said reservoir to the low pressure side of said circulator, and a gas lift pump for conveying solution from said reservoir to said absorber.

4. Absorption refrigerating apparatus comprising a pressure equalizing medium circuit including an evaporator and an absorber, a solution circuit including a boiler-analyzer and said absorber, a condenser in free unobstructed communication with said analyzer and said evaporator, a power driven circulator positioned in the rich mixture portion of the pressure equalizing medium circuit to discharge the rich mixture under pressure into said absorber and to circulate the pressure equalizing medium through said. evaporator with a velocity sufficient to propel the liquid refrigerant through the evaporator, a reservoir in the weak solution portion of the solution circuit, means venting said reservoir to the low pressure side of said circulator, a gas lift pump for conveying solution from said reservoir to said absorber, a vessel connected to receive the discharge of said gas lift pump and vented to the low pressure side of said circulator, and a pressure balancing liquid column forming means connecting said vessel to said absorber.

5. Absorption refrigerating apparatus comprising a pressure equalizing medium circuit including an evaporator and an absorber, a solution circuit including a boiler-analyzer and said absorber, a condenser in free unobstructed communication with said analyzer and said evaporator, a power driven circulator positioned in the rich mixture portion of the pressure equalizing medium circuit to discharge the rich mixture under pressure into said absorber and to circulate the pressure equalizing medium through said evaporator with a velocity sufficient to propel the liquid refrigerant through the evaporator, a reservoir in the weak solution portion of the solution circuit, means venting said reservoir to the low pressure side of said circulator, a gas lift pump for conveying solution from said reservoir to said absorber, means for introducing pressure equalizing medium under pressure into said gas lift pump, a vessel connected to receive the discharge of said gas lift pump and vented to the low pressure side of said circulator, and a pressure balancing liquid column forming means connecting said vessel to said absorber.

6. Absorption refrigerating apparatus comprising a pressure equalizing medium'circuit including an evaporator and an absorber, a solution circuit including a boiler-analyzer and said absorber, a condenser in free unobstructed communication with said analyzer and said evaporator, a power driven circulator positioned in the rich mixture portion of the pressure equalizing medium circuit to discharge the rich mixture under pressure into said absorber and to circulate the pressure equalizing medium through said evaporator with a velocity sufficient to propel the liquid refrigerant through the evaporator, a reservoir in the weak solution portion of the solution circuit, means venting said reservoir to the low pressure side of said circulator, a gas lift pump for conveying solution from said reservoir to said absorber, means for introducing rich pressure equalizing medium under pressure into saidgas lift pump, a vessel connected to receive the discharge of said gas lift pump and vented to the low pressure side of said circulator, and a pressure balancing liquid column forming means connecting said vessel to said absorber.

7. Absorption refrigerating apparatus comprising a pressure equalizing medium circuit including an evaporator and an absorber, a solution circuit including a boiler-analyzer and said absorber, a condenser in free unobstructed communication with said analyzer and said evaporator, a power driven circulator positioned in the rich mixture portion of the pressure equalizing medium circuit to discharge the rich mixture under pressure into said absorber and to circulate the pressure equalizing medium through said evaporator with a velocity sufiicient to provented to the low pressure side of said circulator, and a pressure balancing liquid column forming means connecting said vessel to said absorber.

8. Absorption refrigerating apparatus including a boiler, an analyzer, an absorber, means for circulating fluids through said absorber under pressure, means for conveying strong solution from said absorber to said analyzer, means for conveying weak solution from said boiler to said absorber, means for venting a portion of the weak solution conveying means to the low pressure side of said circulating means, and means for forming a pressure balancing liquid column between said absorber and the vented portion of said weak solution conveying means.

9. Absorption refrigerating apparatus comprising a boiler assembly, a condenser in free and open communication with said boiler assembly, an evaporator in free and open communication with said condenser, an absorber, means forming an inert gas circuit including said evaporator and said absorber, and power driven circulating means connectedin said circuit to discharge rich inert gas into said absorber under pressure and to circulate the inert gas through said evaporator with sufficient velocity to propel the refrigerant liquid therethrough as it is evaporating.

10. In combination, an absorption refrigerating system including a boiler, an analyzer, an absorber, means for conveying strong solution from said absorber to said analyzer, the solution inlet on said analyzer being located at substantially the same elevation as the solution outlet on said absorber, an evaporator, means for liquefying refrigerant vapor generated in said boiler and for supplying the liquid to said evaporator, means for supplying an inert gas under pressure to said absorber and said evaporator, said system being so constructed and arranged that :said

analyzer is subjected to the pressure of the inert gas supplied to the absorber and evaporator, means for conveying weak solution from said boiler to a low pressure area of the system by gravity whereby the solution level in the analyzer is lowered materially below the level of the strong solution inlet to the analyzer and the weak solution level in said low pressure area of the sys- .'tem is materially higher than the solution level in the analyzer.

11. In an absorption refrigerating apparatus of the type including a boiler, an analyzer, an

' absorber and a means for placing a pressure equalizing medium under pressure, that improvement which includes the steps of subjecting the strong solution outlet of the absorber and the strong solution inlet of the analyzer to substantially the highest pressure prevailing in the system and subjecting the weak solution line betweenthe boiler and the absorber to substantially the lowest pressure prevailing in the system.

12. That improvement in absorption refrigerating systems of the type including a boiler,

I an analyzer, an evaporator, an absorber, a means pel the liquid refrigerant through the evapo-' rator, a reservoir in the weak solution portion for producing a pressure difierential across different portions of a pressure equalizing medium circuit including the evaporator and the absorber, a strong solution circuit including the absorber and the analyzer and a weak solution circuit including the boiler and the absorber, which includes the steps of subjecting the absorber end of the strong solution circuit to the highest pressure prevailing in the system, subjecting the analyzer end of the strong solution circuit to the pressure prevailing in the pressure equalizing medium inlet to the evaporator and subjecting the absorber end of the weak solution circuit to the lowest pressure prevailing in the system.

13. Absorption refrigerating apparatus comprising a pressure equalizing medium circuit .including an evaporator and an absorber, a solution circuit including a boiler assembly'and said absorber, a condenser in free unobstructed communication with said boiler assembly and said evaporator, a power driven circulator positioned in the rich mixture portion of the pressure equalizing medium circuit to discharge the rich mixture under pressure into said absorber and to circulate the pressure equalizing medium through said evaporator, means for subjecting a portion of said solution circuit tothe pressure prevailing in a low pressure area of said pressure equalizing medium circuit, andmeans forming a pressure balancing liquid column in said solution circuit for separating the high and low pressure portions thereof.

14. Absorption refrigerating apparatus comprising a pressure equalizing medium circuit including an evaporator and an absorber, a solution circuit including a boiler assembly and said absorber, a condenser in free unobstructed communication with said boiler assembly and said evaporator, a power driven circulator positioned in the rich mixture portion of the pressure equalizing medium circuit to discharge the-rich mixture under pressure into said absorber and to circulate the pressure equalizing medium through said evaporator with a velocity sufficient to propel the liquid refrigerant through the evaporator, a gaslift pump in said solution circuit for circulating the solution therethrough arranged to discharge into a portion of the apparatus which is subjected to a low pressure, and means forming a pressure balancing liquid column for separating the discharge end of said pump from portions of said circuit which are subjected to a high pressure. 7

15. Absorption refrigerating. apparatus comprising a pressure equalizing medium circuit i. n cluding an evaporator and an absorber. a solution circuit including a boiler assembly and said absorber,,a condenser in free unobstructed communication with said boiler assembly and s d evaporator, circulating means positioned in :the rich mixture portion of the pressure equalizing medium circuit to discharge, the rich mixture under pressure into said absorber and to, circula e the pressure equalizing, medium through said evaporator with a velocity sufficient to propel the liquid refrigerant through the evaporator. a pump in said solution circuit forcirculating the solution therethrough arranged to discharge into a portion of the apparatus which is subjected to a low pressure, and means forming-a pressure balancing liquid column for separating the discharge end of said pump from portions of said circuit which are subjected to a high pressure.

l6. In an absorption refrigerating apparatus of the type including a boiler, an analyzer, an absorber and a means for placing a pressure equalizing medium under pressure, that improvement which includes the steps of subjecting the strong solution outlet on the absorber and the strong solution inlet on the analyzer to substantially the highest pressure-prevailing in the system and subjecting the weak solution'line between the boiler and the absorber to substantially the lowest pressure prevailing in the system and elevating. weak solution from such low pressure area tothe absorber.

1'7. Absorption refrigerating apparatus comprising a solution circuit including a boiler and an absorber, an inert gas circuit including an evaporator and said absorber, means for liquefying refrigerant vapor produced in said boiler and for supplying the liquid to said evaporator, a circulating element in said inert gas circuit for developing. a flow producing pressure differential therein, said circuits being arranged to subject the boiler and absorber to the pressure prevailing on one side of said circulating element, and means arranged to maintain a portion of said solution circuit under the pressure prevailing on the other side of said circulating element.

18. Absorption refrigerating apparatus including an evaporator and an absorber connected to form a pressure equalizing medium circuit, means for creating a pressure differential in said pressure equalizing medium circuit to create a flow of pressure equalizing medium therethrough, a vapor generating apparatus andsaid absorber connected to form a solution circuit, means for liquefying refrigerant vapor evolved in said vapor generating apparatus and for supplying the liquid to said evaporator, the arrangement being such that said absorber, vapor generating apparatus, condenser and a part of said evaporator are subjected to the pressure prevailing in a high pressure part of said pressure equalizing medium circuit, pumping means in said solution circuit for elevating absorption solution into said absorber, and connections between the portions of said solution circuit containing said pumping means and said pressure equalizing medium circuit to subject the solution supply and discharge portions of said pumping means to the pressure prevailing in a low pressure area in said pressure equalizing medium circuit.

19. Absorption refrigerating apparatus including an evaporator and an absorber connected to form a pressure equalizing medium circuit, means for creating a pressure differential in said pressure equalizing medium circuit to create a flow of pressure equalizing medium therethrough, a vapor generating apparatus and said, absorber connected to form a solution circuit, means for liquefying refrigerant vapor evolved in said vapor generating apparatus and for supplying the liquid to said evaporator, the arrangement being such that said absorber, vapor generating apparatus, condenser and a part of said evaporator are subjected to the pressure prevailing in a high pressure part of said pressure equalizing medium circuit, pumping means in said solution circuit for elevating absorption solution into said absorber, and connections between the portions of said solution circuit containing said pumping means and said pressure equalizing medium circuit to subject the solution supply and discharge portions of said pumping means to, the pressure prevailing in a low pressure area in said pressure equalizing medium ciriuit, said solution circuit being arranged to form pressure balancing columns of solution between said pumping means and said absorber and between said absorber and said vapor generating apparatus.

20. That improvement in three fluid absorption refrigerating systems of the pressure equalized type utilizing a refrigerant, an absorbent for the refrigerant and a pressure equalizing medium which is inert with respect to the refrigerant and absorbent which includes the steps of circulating the pressure equalizing medium through a circuit by producing a static pressuredifferential in a portion of such circuit, circulating the absorbent through a circuit in which refrigerant vapor is added to the absorbent in one part of said absorbent circuit and refrigerant vapor is removed from said absorbent in another part of said absorbent circuit, circulating the refrigerant through a circuit which is in part common to said pressure equalizing medium and absorbent circuits, and subjecting a selected portion of said absorbent circuit to the static pressure differential produced in said pressure equalizing medium circuit to promote circulation of absorbent through said absorbent circuit.

21. In an absorption refrigerating apparatus having a boiler assembly, a condenser, an evaporator and an absorber, means for circulating a pressure equalizing medium through a circuit including said absorber and said evaporator by producing a pressure differential in a portion of said circuit, means for circulating absorption solution between said boiler assembly and said absorber, and means for conducting refrigerant vapor from said boiler assembly to said condenser and for conducting refrigerant liquid from said condenser to said evaporator, said apparatus being so constructed and arranged that the boiler assembly, the condenser, the pressure equalizing medium receiving portion of said evaporator and said absorber are maintained under the pressure prevailing in a portion of said pressure equalizing medium circuit and a portion of said solution circuit containing weak solution is maintained under a pressure lower than the pressure prevailing in said portion of said pressure equalizing medium circuit.

22. Absorption refrigerating apparatus comprising a boiler-assembly, a condenser in free and open communication with said boiler-assembly, an evaporator in free and open communication with said condenser, an absorber, means forming an inert gas circuit including said evaporator and said absorber, circulating means connected in said circuit for creating an appreciable pressure differential in that part of said circuit in which rich gas is flowing from said evaporator to said absorber to discharge rich inert gas into said absorber under pressure, means for conveying strong solution from said absorber to said boilerassembly, means including a gas containing part for conveying weak solution from the boilerassembly to said absorber, and means connecting saidgas containing part of said weak solution conveying means to said inert gas circuit between said evaporator and said circulatin means.

23. Absorption refrigerating apparatus comprising an evaporator, an absorber, a condenser, a generator assembly, means for conducting inert gas from said absorber to said evaporator, means including a gas pump for conducting inert gas from said evaporator to said absorber, said gas pump being arranged to receive inert gas from said evaporator and to discharge the inert gas to said absorber at a raised pressure, a solution reservoir positioned above the liquid level of said generator assembly, means for conducting solution from said boiler to said reservoir, means for conducting solution from said reservoir to said absorber, means for conducting solution from said absorber to said generator assembly, means connecting said generator assembly to said condenser and connecting said condenser to said evaporator in a manner to subject said generator assembly to the pressure prevailing in a portion of said evaporator and means connecting said reservoir above the solution level therein to a portion of said inert gas conducting means containing inert gas at a pressure below said raised pressure.

JUSTICE H. BEACH.