US2240178A - Absorption refrigeration - Google Patents

Description

G. A. BRACE ABSORPTION REFRIGERATION April 29, 1941.

5 Sheets-Sheet 1 Filed April 4, 1940 l I l r r II INVENTOR 8A. awe

ATTORNEY Gear April 29, 1941. s, A. BRACE ABSORPTION REFRIGERATION Filed April 4, 1940 5 Sheets-Sheet 2 INVENTOR Geor yeAafirace 2 WAI NEY I April 29, 1941. s. A. BRACE ABSORPTION REFRIGERATION Filed April 4, 1940 5 Sheets-Sheet 3 ban INVENTOR George A. flrace My 5mm TTORNEY April 29, 1941. G. A. BRACE 2,249,173

ABSORPTION REFRIGERATION FilGd April 4, 1940 5 Sheets-Sheet 4 5 E I z INVENTOR Gearye A. Brace BY I ' ATTORNEY April 29, 1941. G. A. BRACE ABSORPTION REFRIGERATION Filed April 4, 1940 5 Sheets-Sheet 5 INVENTOR George A. Brace BY A46? 51% ATTORNEY Patented Apr. 29, 1941 ABSORPTION REFRIGERATION George A. Brace, Winnetka, 11]., assignor to The Hoover Company, North Canton, Ohio Application April 4, 1940, Serial No. 327,791

44 Claims.

This invention relates to refrigeration apparatus, and more particularly to a novel absorption refrigeration system, as well as to a novel construction of the principal elements and a unique arrangement of the same in a self-contained assembly.

Absorption refrigeration systems known prior to this invention are characterized by the many rigid limitations imposed upon the construction, arrangement and relative positioning of the parts; and upon the nature and disposition of the several fluid circuits. The present invention proposes an absorption system which entirely avoids these rigid restrictions and offers the designer the greatest freedom in the design of the individual vessels and in the arrangement of such vessels relative to one another. Furthermore, this invention is not only characterized by its unusual flexibility in the construction and arrangement of parts, but by its improved operating characteristics and its greater operating efficiency.

One of the primary problems encountered inthe design and operation of hermetically sealed absorption refrigeration apparatuses is the circulation of the several fluids within the system in their respective circuits and at widely different rates. The problem is furthercomplicated in that all fluid circuits are in open and free communication. In the type of system hereinafter described for purposes of illustrating one manner of practicing the invention, the apparatus is charged with a refrigerant fluid, a liquid solvent therefor, and an inert pressure equalizing medium.

In such a system, it is necessary to provide a circuit for the liquid solvent, a circuit for the refrigerant medium, and a circuit for the inert medium. Each of these circuits overlap in part with at least one other circuit. From these facts, it will be apparent that the circulation of these three mediums in their respective circuits and at widely different rates by a single source of energy is not a simple one. And this problem becomes particularly diflicult if a further requisite is some freedom in the construction and arrangement of parts without sacrifice of efiiciency or operating characteristics.

The use of a hermetically sealed positive displacement pump has long been common practice in compression type refrigeration systems. However, the incorporation of such a pump in a hermetically sealed absorption apparatus has presented many complex problems not solved prior to this invention. Not the least of these prob- -is an object to employ a pump of the aforesaid lems has been that of lubricating the moving parts within the system.

It is accordingly an object of this invention to provide an absorption refrigeration system in which a positive displacement pump of the her metically sealed type is employed to circulate the fluids within the system. More particularly, it

type for circulating a plurality of fluids through different freely communicating circuits and at different relative rates.

Another object of the invention is the provision of an absorption system in which the designer has great freedom in the design and arrangement of the principal vessels relative to one another. Thus the present invention enables a designer to locate the condenser, absorber and evaporator, or any combination of these vessels, in the same general horizontal plane, or in different horizontal planes, irrespective of which of the three vessels is placed at the higher elevat ion. Furthermore, it is possible to utilize gravity flow of liquids through these vessels in all arrangements thereof. Y

Another object is the provision of a system wherein it is possible to secure the advantages of certain inert mediums without sacrificing the many advantages flowing from the passage of the inert gas through bodies of absorption medium and liquid refrigerant medium.

A further object of the invention is to provide an arrangement of an absorption refrigeration apparatus in a cabinet having a refrigerated storage chamber, and in which the relationship of the cabinet and apparatus is novel in various respects.

Another object of the invention is the provision of an absorption system operating in a new and improved manner.

Still another object of the invention is the provision of novel condenser, evaporator and absorber vessels, respectively.

It is another object of the invention to provide a novel motor pump unit, and a novel mode of lubricating and sealing the moving parts thereof;

A further object of the invention is the provision of means for so locating a pump unit in an absorption refrigeration system that the pressure differential across the pump will not adversely affect liquid levels and operating conditions in certain portions of the system.

Another object of the invention is the provision of an absorption refrigeration apparatus in which the absorber and condenser are located in sideby-side relationship, and for whi h the" is prothe top of condenser C, C.

vided a new and improved means of cooling these vessels.

Still other objects and advantages of the invention will become apparent from the detailed description of the invention and a. consideration of the annexed drawings in which:

Figure 1 is a diagrammatic representation of a preferred form of refrigeration system embodying the invention.

Figure 2 is a vertical sectional view through a portion of one of the absorber conduits and showing the internal construction and representing the manner in which the fluids flow.

Figure 3 is a vertical sectional view along line 33 of Figure 4 of the positive displacement pump unit.

Figure 4 is a vertical sectional view of the pumping chamber taken along line 4-4 of Figure 3.

Figure 5 is a vertical sectional view along line 5-5 of Figure 6 of an ice cream cabinet, and

shows a preferred arrangement of the apparatus in such a cabinet.

Figure 6 is a vertical sectional view. along line 66 of Figure 5 and shows other details of the arrangement of the apparatus.

Figure 7 is an isometric view of the frame on which the apparatus may be mounted to form an integral transportable structure.

Referring now to Figure 1, it will be seen that the system comprises a generator assembly including a boiler B and an analyzer D, a rectifier R, a condenser comprising similar, finned conduit assemblies C, C, an evaporator comprising similar tubular assemblies E, E, a refrigerant liquid dividing and elevating device M, an air-cooled absorber comprising similar, finned tubular assemblies A, A, an absorption liquid dividing and elevationg device N, a gas heat exchanger G, a positive displacement pump unit P, a solution reservoir S, and a solution heat exchanger L. These principal elements are interconnected by suitable conduits, as will be described presently,

horizontal, it only being necessary to provide suflicient inclination for gravity flow of the refrigerant therethrough. The internal'construction of the evaporator will be explained presently. The upper and lower ends of the banks are connected by conduits l5 and 16, respectively.

As shown, device M comprises an upright U- tube having legs l2 and I3, and an inverted U- tube [4. The upper ends of legs l2 and I3 discharge into'the top of evaporator banks E and E respectively. Inverted U-tube [4 opens into the lower end of conduits l2 and I3 and serves to introduce inert gas into the refrigerant liquid in these conduits for the purpose of elevating refrigerant liquid therein into the evaporator banks by the well known gas lift pump principle. The manner in which device M functions to divide the refrigerant liquid will become apparent presently.

As illustrated in Figure 1, the absorber comprises two banks A, A- of finned tubing. The straight portions of tubing in each bank are shown as being in the same vertical plane, but, as in the case of the evaporator, the banks may be shaped in any desirable form, and the banks may be inclined at any desired angle to the horizontal. It will likewise be understood that the absorber may comprise a single bank. The upper ends of the banks are interconnected by conto provide a hermetically sealed system capable of withstanding the normal operating pressures of 250 to 350 lbs. per sq. inch, and to provide an ample safety factor.

The generator assembly comprises a conventional boiler B and an upright analyzer D near one end thereof. The analyzer may be either of the dry or flooded type. A refrigerant vapor line It] interconnects the top of the analyzer and Intermediate the end of conduit I0 is a finned, air-cooled rectifier operable to condense absorbent vapor carried by the refrigerant vapor and return the same to the analyzer.

The condenser comprises similar, finned banks of tubing C, C. The two banks may be placed in side-by-side, or end-to-end relationship, the latter arrangement being shown in Figure 1. The lower ends of the condenser banks discharge into conduit. ll leading to the refrigerant dividing and elevating device M. Conduit ll may be provided with heat radiating fins and serve as a refrigerant liquid precooler since this conduit will normally be filled with refrigerant liquid.

The evaporator may comprise one o more vessels positioned laterally of and in the same general horizontal plane as the condenser. As illustrated, the evaporator comprises two banks E ard E. Each :bank is formed from steel tubing bent as indicated in Figure 5, and positioned in a vertical plane. However, it is not/essential that the evaporator banks be located vertically, and the same may be positioned at any angle to the duit l1 and the lower ends are interconnected by conduit I8.

A combined absorption liquid elevating and dividing device N, similar in construction to device M, for the refrigerant liquid, is provided for elevating lean absorption solution from reservoir S to the upper ends of the absorber banks and for dividing the solution therebetween. This device comprises an upright U-tube having legs 19, 20, and an inverted U-tube 2| opening into the lower ends of conduits i9, 20. Like U-tube I 4, U-tube 2| delivers inert gas under pressure into legs I 9 and 20 to operate the pumping and dividing device.

The evaporator and absorber are interconnected by a series of conduits providing an inert gas circuit between and through these vessels.

This circuit comprises a conduit 22 interconnecting the upper end of evaporator banks E, E and one end of the inner passage of gas heat exchanger G. Conduit 23 connects the opposite end of the inner passage directly with the lower end of absorber bank A and with conduit l8 leading into the lower end of absorber bank A. er the inert gas has passed in parallel through the absorber banks, it passes into conduit I1 and is conveyed to the inlet chamber of pump P by conduit 24. The pump discharges the gas under pressure into conduit 25 from which it passes through a gas and liquid separating chamber 26 and into the outer passage of gas heat exchanger G through conduit 21. The opposite end of the outer passage of the heat exchanger leads into conduit 28 which conducts the gas into the lower end of evaporator banks E and E' by means of conduit I 6. It will be apparent that conduit l6 divides the gas between the evaporator banks through which the gas flows in parallel and thus back to conduits l5 and 22, thereby completing the main inert gas circuit.

Pump unit P is of the positive displacement type and is therefore operative to not only circulatethe inert gas through the circuit just described, but also to create a. very considerable pressure differential between the inlet and discharge sides thereof. This pressure differential Aft-.

is suiiicient to overcome a plurality of liquid pressure heads existing in both the evaporator and absorber, as will be explained in detail hereinbelow, and also suilicient to permit introduction of inert gas into pumping and dividing devices M and N.

It is tobe understood that the expression positive displacement, as applied to pump P, is intended to distinguish my pump from fans, blowers, vapor operated jets and other similar gas circulating devices which have been previously proposed and which do forcibly and positively circulate gas, but do not do so by positive displacement action. Compressors, suchas that herein disclosed, do positively displace the fluid being worked upon.

Thus, it will be observed that conduit 29 interconnects high pressure conduit 21 and inverted U-tube M of device M, while a similar conduit 30 conveys inert gas into inverted U-tube 2| of device N. It will be noted that bleed conduits 29 and 30 are much smaller than the con-' duits of the main inert gas circuit and that the small amount of inert gas flowing therethrough by-passes the evaporator and the absorber, respectively. It will also be noted that the inert gas pressure on the inlet ends of devices M and N is approximately that on the discharge side of pump P, while the gas pressure at the discharge end of devices M and N is much lower. The pressure at the top of the evaporator banks into which device M discharges is less than that at .the inlet end by reason of the pressure 'drop across these banks. On the other hand, the inert gas pressure at the upper end of absorber banks A and A is approximately the inlet pressure of pump P. Consequently, the pressure drop across device N is considerably greater than the pressure drop across device M thereby enabling device N to operate through a considerably greater vertical height than device M.

Inverted U-tubes l4 and 2| of the pumping devices are preferably so constructed that when the apparatus is shut down the liquid level in the legs of .the pump is insuflicient to overflow into bleed conduits 29 and 30. However, even should the liquid overflow into these conduits, no harm will result because the liquid will flow into conduit 21 and separator 26 from which it will be returned to the absorption solution circuit.

The absorption solution circuit is formed by a plurality of conduits interconnecting the refrigerant generator and the absorber. This circuit comprises conduit 3| conveying hot lean solution from boiler B to the outer passage of the solution heat exchanger L. The solution then is .conveyed through a suitable pro-cooling device, such as finnedconduit 32', and then through conduit 33 into reservoir S. Conduit 34 conveys the solution into the inlet of device N in which it is divided and elavated into the upper end of absorber banks A, A. The solution flows downwardly by gravity through the banks and in counterflow to the inert gas flowing upwardly therethrough. The lower ends of the absorber banks discharge into conduit I8 in which the solution tical height.

portion of the absorption solution returning to the generator. For this purpose, a U-tube 38 has one end connected to chamber 35 and the opposite end connected to the bight of a second U-tube 39. The legs of this latter U-tube discharge near the central, opposite faces of the pump rotor and maintain a film of absorption solution between the faces of the rotor and the casing.

One end of U-tube 38 projects above the bottom of chamber 35 but to a lesser extent than the upper end of conduit 36 of the mainsolution circuit. An adequate and substantially uniform liquid head is thus assured for the lubricating solution flowing to the pump. By locating pump P at the proper distance below chamber 35,-it is possible to assure a supply of liquid to the pump which is adequate for lubricating and sealing purposes but which is not great enough to cause appreciable flow through conduits 38 and 39. This prevents the flow from becoming great enough to interfere with the gas pumping functioning of the pump. Lubricating solution which does pass beyond the pump rotor passes through conduit 25 into the gas and liquid separator chamber 26 from which it is returned to the main solution circuit through conduits 40 and 4|. It will also be evident that separator 26 serves to prevent liquid carried by the gas discharging from the pump from being carried into the evaporator.

It sometimes happens that unevaporated refrigerant reaches conduit 16 interconnecting the evaporator banks, or absorption solution may eventually collect in undesirable quantities in the bottom of. the evaporator. If not removed,

. this liquid will interfere with the operation of the system. Such liquids are drained from the evaporator as they collect through conduits 42 and 4|, and are returned to the absorption solution circuit.

It is also desirable to prevent liquid refrigerant from collecting to too great a height in the condenser. This may be avoided by placing a drain conduit 43 at a suitable height on the condenser bank and connecting this drain with conduit 4| leading to the absorption solution circuit.

It is also necessary to provide a purging device for the condenser in order to remove inert gas which inevitably reaches the condenser. For this purpose, a conduit 44 interconnects the lower portions of the condenser banks and discharges into conduit 45 which in turn discharges into conduit 24 of the principal inert gas circuit. By reason of this arrangement, it will be understood that the apparatus may occupy a minimum ver- The reason for this is as follows: Since the analyzer D is in open and in free communication with conduit 24 leading to the intake side of pump P, the pressure prevailing in the boiler and analyzer will be substantially that on the intake side of pump P.' It is-therefore possible to position the boiler at a higher elevation than would otherwise be possible. Consequently, reservoir S can be located at a higher elevation.

It will also be noted that a gas vent 46 is provided between conduit 24 and reservoir S for the dual purpose of permitting gas which may collect above the liquid in the reservoir to escape, and for placing the reservoir under the same pressure conditions as boiler B. Thus, it will I be seen that the pressure prevailing at boiler B and reservoir S, which are at the opposite ends of the weak absorption liquid circuit formed by conduits 3|,.32 andrr33, is equalizedby means of purging conduits 44, 45 and venting conduit 46.- The discharge pressure of pump P' is prevented from affecting conditions in the boiler by reason of the liquid columns formed in conduits 85, 48, 4| and 42 which are of sufiicient height in all cases to balance pressure developed by the pump.

The internal construction of the absorber will now be described. Referring to Figure 2, which shows a..cut-a-way section of one of the conduits in absorber bank A, it will be seen that inserts are employed to form pools of absorption liquid. It will be understood that the straight sections of tubing in both absorber banks have similar inserts. The spacing of the inserts may vary in different portions of the banks.

Spaced along the lower inner side of the absorber conduits are inverted U-shaped members having liquid tight engagements therewith. Since the absorber conduit is inclined slightly to the horizontal, as indicated in Figure 2, inserts 48 form pools 49 and 50 of absorption liquid therebehind. Near the upper end of inserts 48 and on the downstream side are small openings Within this opening may be mounted a pair of twisted wires .52 which overlie the next lower pool of solution and extend in a direction generally parallel to the axis of the absorber conduit. Near the bottom, upstream side of inserts 48 is another opening 53. By reason of the open-- ings just described, the absorption liquid does not overfiow the top of the inserts, but instead is withdrawn from the bottom of the pool through opening 53, and passes out through opening 5| and along the twisted wires 52 in a thin film. By this means lean solution stratified in the bottom of one pool is delivered to the top .of the next pool.

Spaced slightly behind inserts 48 are upper inserts or baflles 54 which extend below the surface of the absorption liquid pools. Accordingly,

the refrigerant-laden insert gas entering the bottom of the absorber is caused to bubble through the absorption liquid pools in order to by-pass baffles 54. Hence, the refrigerant vapor is bubbled through absorption liquid, then in wiping contact with the surface of the pool, across the thin film of solution on twisted wires 52 and then through another pool .of liquid. This action is repeated again and again as'the gas passes upwardly through the absorber in counterflow to the absorption liquid.

The internal construction of the evaporator is preferably identical with that just described for the absorber with the exception that the groups of inserts 55 may and preferably are spaced much farther apart. By spacing the groups of inserts 55 at a considerable distance from one another, it is possible to distribute the refrigerant liquid throughout a very long evaporator conduit and thereby distribute the refrigerating effect. This greater spacing of the inserts is employed particularly where it is desirable to distribute the refrigerating effect throughout a large chamber. For example, in the application of the invention to an ice cream cabinet as shown in Figure 5, it is desirable to extend the evap- These several housing elements are suitably joined together, as by Welding, after which the final machining operations may be performed to insure that all parts will be in proper alignment. Magnetic section 58 of the motor housing is preferably made very thin and serves as a high permeability path for the flux flowing between the motor field and armature.

the flux to its proper path.

Within the pump unit housing is mounted a shaft 50 carrying motor armature 5| and pump rotor 62. A sleeve bearing 53 supports one end of the shaft in housing element 59. Bearing 64 supports the shaft at a point between the armature and the pump rotor and is mounted within a hollow spindle 85 carried by plate 66. Closing the open end of thepump rotor chamber 61 is a cover plate 58. The adjacent faces of plates 66 and 88, as well as the seats for the plates in housing 58, are very accurately ground as are the outer faces of pump rotor 62. Rotor 52 is secured to shaft and is so mounted within the pump chamber that it forms a very close fit with plates 66 and 58 and with the bottom of chamber 61. is eccentrically mounted within the pump chamber.

The field for the motor comprises a laminated field 69 upon which are wound field coils 10. This field assembly forms a close sliding fit with the outer surfaces of shell members 58 and 59, and is forced into position over the right-hand end of the pump shell. The field stack may be secured in position by suitable keepers 1|. Since the field assembly is mounted exteriorly of the system, it is not necessary to employ materials immune to attack by the refrigerant fluids as is necessary in the case of all elements employed inside the system.

Armature BI is mounted upon shaft 60 opposite the field assembly and magnetic section 58 of the pump shell. The motor is of the induction type and the armature may comprise laminated members within which are embedded conductors of aluminum. The armature may then be coated with aluminum or other suitable material to protect the same from attack by the refrigerant fluids.

By virtue of the motor construction just described, it will be apparent that a very simple motor has been provided in which all parts within the system are properly protected from the refrigerant fluid, and for which it is not necessary to b i g electrical conductors through the 13. Rotation of armature 5| will throw the lubricant upon the bearings. Any lubricant which fiows beyond'the lefthand end of bearing 64 is returned to chamber 13 by drain pipe 14. A throwofi ring 15 upon shaft 50 prevents the lubricant from passing along the shaft into pump chamber 81.

It will also be understood that due to the special construction of housing 51, spindle 65 and drain pipe 14, it is impossible for the lubricant to escape from chamber 13 regardless of the position of pump unit P. For example,.if the pump unit should be turned in a counterclockwise direction from its position in Figure 3, the level ofthe lubricant would be well below .the openend of spindle 65 and of drain 14. And if the pump unit should be placed in any other position, the level would be such that no lubricant could escape.

Referring now to Figure 4, it will be seen that The non-magnetic properties of sections 51 and 58 serve to confine As shown in Figure 4, the rotor a plurality of pumping blades I6 are slidingly carried in radial guides 11 of rotor 52. The outer ends of blades I6 may be rounded as shown, and the blades may be 'made principally of graphite composition molded upon a central reinforcing member. The blades are continually urged against the inner face of pump chamber 61 by coil springs I8 or the like. Conduit 24 of the inert gas circuit supplies gas to intake chamber I9. After the gas has been compressed by blades 16 and rotor 62, it is conveyed from the pump through discharge port 80.

The manner in which the pump rotor is lubricated and sealed against leakage of gas therepast will now be described by reference to Figure 3. Absorption solution under a substantially constant head is conveyed to the opposite faces of rotor 62 by U-tube 39. The lefthand leg of the U-tube discharges into the small clearance between rotor 62 and plate 68 opposite the end of shaft 60, while the other leg of the U-tu'oe discharges into the space between the rotor and plate 66 at a point directly below the shaft.

The slight clearance between the rotor and the housing prevents any material flow of absorption solution, but suffic ient solution is discharged into the space to provide a very effective seal as well as to provide a film of lubricant between the rotor and the walls of chamber 61.

Due to the proximity of the solution supply to shaft 60 on the motor side of the rotor, and to the effect of centrifugal action, there is little or no tendency for the solution to flow up into spindle 65. However, to avoid any possibility of solution flowing into chamber I3 through hollow spindle 65, any suitable labyrinth sealing device, such as indicated at 8|, may be provided on shaft 60 between throwofi ring I and rotor 62.

The system is charged in known manner with a refrigerant medium, such as ammonia, an absorption solution medium therefor, such as water, and an inert gas. Although any of the well known inert gases may be employed, superior results can be obtained by using a gas having 'good heat conducting properties. Hydrogen is therefore a preferred inert medium.

The general mode of operation of the'refrigeration system itself will be apparent to those skilled in the art in view of the foregoing detailed description of the apparatus itself. Upon demand for refrigeration, a suitable thermostatic control operates to supply fuel to a gas burner positioned to heat boiler B. Pump unit P may be energized by the control simultaneously with the burner, or subsequently in response to a temperature rise in refrigerant vapor line I0 or other part of the apparatus indicating that the boiler is at a desirable operating temperature. Ammonia vapor distilled from a rich solution of ammonia and water in the boiler is conducted to the condenser through 'conduit II). Water vapor present in the ammonia vapor condenses in rectifier R and returns to the analyzer by gravity.

Ammonia which has been condensed in condenser banks C, C flows by gravity into elevating and dividing device M. A small amount of the hydrogen flowing in the principal inert gas circuit is bubbled under pressure into ammonia liquid standing in legs I2 and I3. Because it is impossible to introduce exactly equal amounts of gas into legs I2 and I3 at any given'instant, the

liquid in the tubeconnecting legs I 2 and I3 will begin to oscillate. The inertia of this oscillating body of liquid contributes materially to the operation of device M both-as respects the elevat- E and E in substantially equal parts. And this a result is obtained regardless of the rate at which refrigerant liquid is supplied to the pump.

Since substantially .pure hydrogen is supplied to the pumping device and'flows in direct contact with ammonia, evaporation of ammonia into the gas will take place in legs I2 and I3 and produce a refrigerating effect. This may be, and preferably is, avoided or minimized by embedding the pumping device in heat insulating material.

The ammonia flows downwardly through the evaporator banks by gravity and collects in pools behind inserts 55 (Figure 5). After the apparatus has been in operation for a period of time the liquid ammonia will be distributed in pools throughout the length of the, two evaporator banks.

The main stream of hydrogen flows upwardly through the evaporator banks under the pressure developed by pump P, and in doing so is caused to bubble through the ammonia pools by that part of inserts 55 corresponding to baffles 54 in the absorber. As a result of this bubbling action and the passage of the hydrogen in wiping curl.- tact with the surface of the ammonia pqol sf'vaporation of ammonia takes place into the gas thereby producing refrigeration. The refrigerant-laden inert hydrogen gas is conducted from the evaporator through conduit 22, gas heat exchanger G, and is introduced into the bottom of absorber banks A, A.

Meanwhile, absorption solution from which the refrigerant has been distilled in the boiler is conducted into reservoir S. From here the lean solution is conveyed to solution dividing and elevating device N which functions in substantially the same manner as device M described hereinabove. The equal portions of solution delivered to the top of the absorber banks flow downwardly through the respective banks collecting in pools behind inserts 48. As the refrigerant-laden hydrogen gas bubbles through the pool and around baffle 54, the ammonia vapor is brought into intimate contact with the water and is absorbed thereby. It will also be appreciated that considerable ammonia vapor is absorbed as it passes over the surface of the pools and past the film of absorbent on twisted wires 52. The heat of absorption is readily conducted either by the hydrogen or by the absorption solution to the side walls of the absorber conduit from which it is readily dissipated to cooling air flowing thereover. By the time the hydrogen reaches the top of the absorber banks, substantially all of ,the ammonia has been absorbed by the water. The

hydrogen then flows into intake chamber I9 of pump P and is again compressed and circulated through the inert gas circuit.

By the time the water has trickled slowly down through the absorber banks; it will have been saturated with ammonia vapor. This enriched solution flows into chamber 35 and the majorportion returns to the boiler after passing in heat exchange relation with the lean solution in heat exchanger L, and after passing in counterfiow to the hot refrigerant vapors in analyzer D.

The reasons for and advantages of dividing the condenser, evaporator and absorber into more than one bank operating in parallel will now be more readily understood. By dividing the condenser into two banks C, C and locating the same side by side, the height of the condenser may be cut in half, This arrangement makes it practicable to elevate the condensate into the top of the evaporator vessel the upper portions of which are in the same general plane as the top of the condenser.

The arrangement of the evaporator in similar banks E, E is advantageous since this construction provides a convenient and highly efficient mode of cooling large chambers, like ice cream storage compartments, uniformly.

The construction of the absorber in two similar banks A and A has several advantages. For example, the absorber may be located in a compartment having the same general dimensions and elevation as that containing the condenser. Of greater importance is the fact that the' bottom of the absorber is conveniently spaced at the required distance above reservoir S without unnecessarily increasing the overall height of the apparatus. The absorber arrangement and construction just described also makes it an easy matter to provide for the liquid columns in conduits 49, 4| and 42 which balance the pressure on the discharge side of pump P and prevent this pressure from being reflected to the boiler.

Referring now to Figures 5, 6 and 7, a preferred mode of arrangement of the apparatus and a manner in which the same may be incorporated in a cabinet will be described. Figure shows the apparatus mounted within an ice cream storage and serving-compartment for purposes of illustration, and it will of course be understood that the apparatus may be applied to various other types of cabinets and installations. A suitable, heat insulated storage compartment 82 is secured upon a supporting base 83 which extends for some distance beyond the righthand end of the insulated compartment. Compartment 82 may be of conventional construction except that end wall 84 is formed separately and, as shown herein, is formed integrally with the refrigeration apparatus. End wall 84 separates the refrigeration apparatus compartment 96 from the ice cream storage chamber 81. The apparatus compartment is formed by a removable casing member 85 forming an extension of the insulated compartment. The top of this casing may be reticulated as at 88 to provide for the passage of cooling air for the apparatus.

The refrigeration apparatus proper is mounted upon and secured to a supporting framework best illustrated in Figure 7. The principal part of the framework comprises a series of innerconnected channels, angles and strap members generally designated by the character 89. End wall 84 of the insulated compartment is secured directly to one face of this framework and the end of evaporator banks E and E adjacent thereto are suitably secured to this wall and the adjacent members of the frame. The opposite nds of the evaporator banks are held in position by supporting and bracing members 90. For smaller constructions, it is unnecessary to provide connecting framework members between elements 89 and 99. In larger constructions or where greater security is desired, additional connecting and bracing members may extend between elements 89 and 99. A metal panel member 9| may be provided in framework 89 to divide the upper portion thereof into two compartments to insure the proper flow of cooling air.

Figures 5 and 6 show the manner in which the condenser, absorber, solution reservoir, boiler and the gas circulating pump, aswell as the various conduits interconnecting the same, may be arranged in framework 89. Thus, the banks of the absorber and condenser are arranged generally parallel to one another upon opposite sides of partition 9|. The boiler assembly is located below the condenser and adjacent the end wall of housing 95. Pump P is also located above and to one side of the boiler. Due to this arrange ment, the motor for the pump and the heating device for the boiler and the controls therefor are made readily accessible for adjustment and repair.

A suitable burner and-control system for the apparatus is indicated in Figure 6. The burner may comprise a conventional type of Bunsen burner 92 having a thermostatic safety-cut-off device 93 positioned to be responsive to the heat of the burner flame. A master electrically controlled valve 94 is located in the gas supply pipe 95 and controls the fuel supplied to the burner except for the small valve-controlled bypass 96. An electrically actuated switch mechanism 91 controlled by thermostatic bulb 98 positioned within the refrigerated storage compartment controls the electrical supply from source 99 for master valve 94 and the motor of pump P.

While the apparatus gives entirely satisfactory results when the cooling air flows over the absorber and condenser by convection, yet it is possible to arrange the apparatus much more.

compactly without sacrificing capacity if forced air flow is employed. As indicated in Figure 6, a small motor driven fan unit I99 and a suitable air distributor l0l may be located directly below the absorber and condenser banks. Room air is drawn into the bottom of the apparatus compartment through louvers such as louvers I92 in the base of the compartment. This air is drawn into the fan unit I09 through an axially disposed inlet opening and is discharged upwardly over the condenser and absorber banks through distributor IOI. Thehot air is then discharged from the casing through opening 88 in the top of casing 85. The fan may be connected in parallel with pump unit P and controlled by controls 91, 98.

From the foregoing description of a preferred embodiment of the invention, it will be appreciated that a novel absorption refrigeration apparatus has been disclosed having many unique features.- Although only one embodiment of the invention has been described, it will be obvious that many changes in the construction and arrangement of parts may be made without departing from the scope or the fundamental principles of the invention. For example, the principal vessels comprising the evaporator, absorber and condenser may be located in different planes and at different elevations. The refrigerated storage compartment shown in Figure 5 may be converted into a plurality of compartments maintained at different temperatures by the simple expedient of providing partitions extending crosswise of the compartment in a generally horizontal plane. Since the greater portion of refrigerant will evaporate in the lower and midportion of the evaporator banks, the lower compartment will be maintained at a lower tempera ture than the higher compartment.

It will also be apparent that the apparatus lends itself admirably to air conditioning. For this purpose, the evaporator banks could be placed directly in an air conduit through which air to be conditioned is circulated. Or the evaporator coils could be located in a compartment containing a fan for circulating air from the room thereover and discharging it back into the room. In either construction, it would only be necessary to rearrange the evaporator coil so that the same occupies less cabinet space. If the device is to be employed as a unit room air conditioner, the heat dissipating portion of the apparatus should be surrounded by insulation to avoid loss of heat to the room, and provision should be made to circulate outside cooling air thereover and discharge the same back to a point outside the room.

It will also be apparent to those skilled in the art that still other changes may be made without departing from the spirit of my invention or the scope of the claims.

I claim:

1. In combination, an absorption refrigeration apparatus comprising a generator assembly, a condenser, an evaporator vessel, an absorber vessel, conduits interconnecting said generator, absorber, evaporator and condenser to provide an absorption solution circuit between said generator and absorber, an inert gas circuit between said absorber and evaporator, and a, refrigerant medium circuit between said generator, condenser, evaporator and absorber, said apparatus being charged with a refrigerant, an absorbent medium therefor and an inert gas, a power operated positive displacement gas pump in said:

inert gas circuit, said pump being hermetically sealed within said apparatus, said evaporator and absorber vessels being constructed to contain a body of refrigerant liquid and a body of absorption solution respectively, and means cooperating with said pump to introduce the inert gas into liquid directly from the bottom portion of each of said vessels as the gas is circulated therethrough.

-2. In combination, an absorption refrigeration apparatus comprising a generator assembly, a condenser, an evaporator vessel, an absorber vessel, conduits interconnecting said generator, absorber, condenser and evaporator to provide an absorption solution circuit between said generator and absorber, an inert gas circuit between said evaporator and absorber, and a refrigerant medium circuit between said generator, con denser, evaporator and absorber, said apparatus being charged with a refrigerant, an absorbent medium therefor and an inert gas, said evaporator and absorber vessels being positioned laterally of one another, said generator assembly being positioned so that the liquid surface level therein is materially below the lowermost liquid surface level in said absorber, a body of refrigerant liquid in said evaporator, a body of absorption liquid in said absorber, a positive displacement pump hermetically sealed within said apparatus operative to circulate the inert gas through the inert gas circuit, and means for introducing the circulating gas into the body of refrigerant liquid and thereafter into the body of absorption liquid.

3. In combination, an absorption refrigeration apparatus comprising a generator, a condenser, an evaporator vessel, an absorber vessel, said absorber vessel being positioned at a higher elevation than said generator, conduits interconnecting said generator, absorber, evaporator and condenser to provide an absorption solution circuit between said generator and absorber, an inand absorber, said apparatus being charged with a refrigerant, an absorbent medium therefor and one of said vessels being located at an angle to the horizontal, each of said vessels being adapted to normally contain a body of liquid, a power operated positive displacement gas circulator hermetically sealed within said inert gas circuit to circulate the inert gas, means operated by the pressure produced by said circulator to circulate absorption solution through said absorption solution circuit, and means operable to introduce a major portion of the circulated inert gas into the body of liquid in said evaporator and absorber vessels as the gas circulates through said gas circuit.

4. An absorption refrigeration apparatus including a refrigerant generator, an evaporator, and an absorber, conduits interconnecting the generator and absorber to provide an absorption solution circuit therebetween, conduits interconnecting the absorber and evaporator to provide an inert gas circuit therebetween, power driven means including a gas impeller located within said inert gas circuit to circulate the inert gas between the absorber and evaporator, means for by-passing some of the absorption solution from the absorption solution circuit through a path including the inert gas circulator, and means for utilizing the solution so by-passed to lubricate the inert gas impeller and to provide a liquid seal to prevent gas by-passing the impeller.

5. In combination, an absorption refrigeration apparatus of the type employing a liquid solution of a refrigerant medium in anabsorbent medium and an inert fluid as working mediums, said apparatus including a refrigerant generator, an absorber, and an evaporator, conduits interconnecting said generator and absorber to provide an absorption solution circuit therebetween, conduits interconnecting said absorber and evaporator to provide an inert gas circuit therebetween, a motor driven positive displacement gas circulator hermetically sealed within said inert gas circuit,

said circulator including a rotating impeller, and means for utilizing a liquid working medium within the apparatus for lubricating relatively moving parts of said circulator.

6. In combination, an absorption refrigeration apparatus including a refrigerant generator, an absorber, and an evaporator, conduits interconnecting the generator and absorber to provide an absorption solution circuit therebetween, conduits interconnecting the absorber and evaporator to provide an inert gas circuit therebetween, a por-- tion of said inert gas circuit being enlarged and constructed to provide a housing for an inert gas impeller element and a driving armature element therefor, a gas impeller element and a driving armature element operatively mounted within said housing, electro-magnetic means outside said housing positioned to operate said armature element when energized, independent means for lubricating said impeller element and said armature elment, and means to prevent the transfer of lubricant for the impeller or armature elements into the lubricant for the other element.

7. In combination, an absorption refrigeration apparatusincluding a refrigerant generator, an absorber, and an evaporator, conduits interconnecting the generator and absorber to provide an absorption solution circuit therebetween, conduits interconnecting the absorber and evaporator to provide an inert gas circuit therebetween,

a portion of said inert gas circuit being enlarged and constructed to provide a housing for an inert gas impeller element and a driving armature element therefore, a gas impeller element and a driving armature element operatively mounted within said housing, electro-magnetic means outside said housing positioned to operate said armature element when energized, independent means for lubricating said impeller and said armature elements, and means to prevent the transfer of lubricant for the impeller or armature elements into the lubricant for the other element, one of said lubricants being a refrigerant working medium in liquid phase, and the other lubricant being a medium other than a refrigerant working medium.

8. In combination with an absorption refrigeration apparatus of the type having an absorption solution circuit extending between a refrigerant generator and an absorber vessel, and an inert gas circuit extending between the absorber and an evaporator, a positive displacement gas circulator hermetically sealed to said inert gas circuit, and means for supplying solution from said absorption solution circuit under a substantially uniform head to said circulator to lubricate relatively moving parts thereof.

9. In combination, an absorption refrigeration system containing hydrogen as an inert gas and having a refrigerant generator, an absorber, an evaporator and a condenser, conduits interconnecting the generator, absorber, evaporator and condenser to provide an absorption solution circuit between said generator and absorber, and an inert gas circuit between said evaporator and absorber, said evaporator and absorber being positioned at different elevations, a gas circulating device within said inert gas circuit to circulate the gas therethrough under pressure, means for passing hydrogen under pressure into and through absorption liquid in said absorber as the liquid circulates therethrough, means for introducing hydrogen under pressure into and through refrigerant liquid in the evaporator and means for returning excess and unevaporated residue liquid in the evaporator to the absorption solution circuit.

10. In combination, an absorption refrigeration system having a refrigerant generator, an absorber, an evaporator and a condenser, conduits interconnecting the generator, absorber, condenser and evaporator to provide an absorption solution circuit between said generator and said absorber and an inert gas circuit between said absorber and evaporator, said evaporator and absorber being ofiset from one another and having portions at the same elevation, a gas circulating device within said inert gas circuit to circulate the gas through its circuit under pressure, means for passing inert gas under pressure into and through absorption liquid in said absorber as the liquid circulates therethrough in counterflow to said gas, means for introducing the inert gas into liquid refrigerant in said evaporator as the liquid circulates from one point to a second point in counterflow to said gas, and means including a liquid seal for returning excess and unevaporated refrigerant liquid from said second point to the absorption solution circuit.

11. An absorption refrigeration system including a refrigerant generator, a condenser, an evaporator and an absorber,-conduits interconnecting said generator, condenser, absorber and evaporator in circuit including conduits providing an inert gas circuit between the absorber and the evaporator, said condenser, evaporator and absorber vessels being constructed from tubular conduits, said absorber and evaporator vessels having parts located at the same elevation, and means including a positive displacement motor operated pump in said inert gas circuit operative to circulate said solution between the absorber and the generator, said pump having a movable element hermetically sealed within said system to introduce the inert gas into absorption liquid in the absorber.

' 12. An absorption refrigeration system including a refrigerant generator, a condenser, an evaporator and an absorber, conduits interconnecting said generator, condenser, absorber and evaporator in circuit including conduits providing an inert gas circuit between the absorber and the evaporator, said condenser, evaporator and absorber vessels being constructed from tubular conduits and said absorber and evaporator vessels having parts located at the same elevation, and means including a power operated positive displacement pump in said inert gas circuit operative to elevate refrigerant liquid into the evaporator and to introduce inert gas into the refrigerant liquid in the evaporator to promote the evaporation thereof.

13. An absorption refrigeration system including a refrigerant generator, a condenser, an evaporator and an absorber, conduits interconnecting said generator, condenser, absorber and evaporator in circuit including conduits providing an inert gas circuit between the absorber and the evaporator, said condenser, evaporator and absorber vessels being constructed from tubular conduits, said absorber and evaporator vessels each having a part thereof located at the same elevation, and a motor operated inert gas circulator in said inert gas circuit operative to elevate absorption solution into said absorber and refrigerant liquid into said evaporator and also operative to introduce inert gas into absorption liquid in the absorber and into refrigerant liquid in the evaporator.

14. An absorption refrigeration system having a refrigerant generator, an absorber, a condenser and an evaporator, conduits interconnecting said vessels in circuit including an inert gas circuit between the absorber and the evaporator and an absorption solution circuit between the generator and the absorber, a positive displacement pump hermetically sealed within said inert gas circuit and operative to circulate the inert gas therethrough under suflicient pressure to introduce the gas into a body of liquid in said inert gas circuit, means interposed between the inert gas circuit and the absorption solution circuit to prevent pressures developed by said gas circulator from being transmitted to said generator, and means to conduct inert gas from said condenser to a low pressure portion of said inert gas circuit.

15. In combination, an absorption refrigeration apparatus including a refrigerant generator, a condenser, an absorber, and an evaporator, conduits interconnecting the absorber and evaporator to provide an inert gas circuit therebetween, means for circulating the inert gas under pressure and for introducing the inert gas into refrigerant liquid in said evaporator, and means for utilizing a portion of the inert gas for elevating liquid refrigerant from said condenser into said evaporator.

16. In combination, an absorption refrigeration apparatus including a refrigerant generator,

liquid refrigerant between said evaporator vessels.

17. In combination, an' absorption refrigeration apparatus of the inert gas type including a refrigerant generator, an absorber, and a plurality of evaporator vessels, conduits interconnecting said absorber and evaporator vessels in an inert gas circuit, means for circulating inert gets under pressure through said gas circuit and through refrigerant liquid in eachof said evaporator vessels, and means utilizing inert gas underpressure for elevating refrigerant liquid into and dividing refrigerant liquid between said evaporator vessels.

18. An absorption refrigeration apparatus of the type employing an inert gas comprising a refrigerant generator, an absorber and an evaporator, conduits interconnecting the generator and absorber in an absorption solution circuit, conduits interconnecting the evaporator and absorber in an inert gas circuit, said absorber comprising a plurality of parts through each of which the absorption solution and inert gas flows independently of the other, means for circulating absorption solution between the generator and each of said absorber parts, and means for introducing the inert gas into absorption liquid in one of said parts as the gaspasses through said part in counterflow, to the absorption solution.

19. An absorption refrigeration apparatus of the type employing an inert gas and comprising a refrigerant generator, an evaporator and a plurality of absorber, vessels, means for providing an absorption solution circuit between said generator and said absorber vessels, means for providing an inert gascircuit between said evaporator and said absorber vessels, means for circulating the inert gas in its circuit under pressure, means for causing the inert gas to bubble through absorption liquid in said absorber vessels, and means for dividing the absorption solution between said absorber vessels.

20. An absorption refrigeration apparatus of the type employing an inert gas and including a refrigerant generator, a plurality of absorber vessels and an evaporator, conduits providing an absorption solution circuit between said generator and said absorber vessels, conduits providing an inert gas circuit between said absorber vessels and said evaporator, means for circulating the inert gas in its circuit under pressure, means for bubbling the inert gas through absorption liquid in said absorber vessels, and means utilizing a portion of the inert gas under pressure for dividing absorption liquid between said absorber vessels.

21. An absorption refrigeration apparatus of the type employing inert gas comprising a refrigerant generator, an evaporator and an absorber, conduits providing an inert gas circuit between said evaporator and said absorber, conduits providing an absorption solution circuit between said generator and said absorber, means within said absorber for forming a plurality of vabsorption. liquid pools therein, means for withdrawing absorption solution from the bottom of one pool and delivering it to the upper portion of another pool, and means for bubbling inert gas laden with refrigerant vapor through absorption liquid in said pools.

22. An absorption refrigeration apparatus of I the type employing inert gas comprising a respaced along said tubular absorber for forming pools of absorption liquid therein, means .for withdrawing absorption liquid from the bottom of one pool and delivering it to the upper portion of another pool, means for passing inert gas under pressure through said tubular absorber in counterflow to the absorption liquid therein, and means for causing the inert gas to bubble through the absorption liquid in the upper portions of the pools;

23. An absorption refrigerating apparatus comprising a refrigerant generator, a tubular air-cooled absorber, and an evaporator, conduits providing an absorption solution circuit between said generator and absorber, conduits providing an inert gas circuit between said absorber and evaporator, said apparatus being charged with a refrigerant medium, an absorbent medium therefor, and hydrogen as the inert gas, means for positively circulating said hydrogen through the inert gas circuit, means forming a plurality of absorption liquid pools in said absorber, and means to cause said hydrogen to be bubbled into said absorption liquid pools and laterally across the surface thereof.

- 24. In combination, a cabinet having a greater horizontal dimension than vertical dimension, a heat insulated compartment in said cabinet,- absorption refrigeration apparatus removable as a unit from said cabinet, said apparatus including a heat absorbing element in said heat insulated compartment, heat dissipating elements within said cabinet but outside said insulated compartment and including a tubular absorber vessel and a tubular refrigerant liquefying vessel, said heat absorbing vessel and one of said heat dissipating vessels each having a portion in the same horizontal plane, said heat dissipating vessels beingglocated in a cooling air flue in communication with a source of cooling air.

25. In combination, a. unitary absorption refrigeration apparatus mounted upon a framework, a cabinet enclosing said framework, said cabinet having a plurality of compartments in- I cluding a heat insulated compartment, said refrigeration apparatus being constructed and arranged so that an evaporator is located in one of said compartments and a heat dissipating portion including an absorber vessel and a refrigerant liquefying vessel is located in another of said compartments, said evaporator and absorber being ofiset from one another, and means providing for the circulation of a cooling medium over said heat dissipating portions of the apparatus to cool the same, said unitary apparatus and said cabinet being so constructed and arranged that the one is readily separable from the other. A

26. In combination, a framework, an absorption refrigeration apparatus mounted upon said framework comprising a tubular evaporator vessel, a tubular absorber vessel, a tubular refrigerant liquefying vessel, a heat insulating partition separating said evaporator from said absorber. said absorber and evaporator being positioned laterally of one another on opposite sides of said partition, conduits interconnecting said evaporator and absorber and including a power operated device for circulating an inert gas through said conduits, power operated means for circulating a cooling medium over said absorber and refrigerant liquefier and common control means responsive to thetemperature condition of one of said vessels for controllingthe operation of said inert gas circulator and said cooling medium circulator.

27. In combination, a framework, absorption refrigeration apparatus mounted upon said framework, saidapparatus comprising a refrigerant generator, an evaporator, an absorber, and a refrigerant liquefier, said evaporator and said absorber being positioned upon opposite sides of a heat insulating partition, conduits interconnecting said evaporator and absorber to provide an inert gas circuit therebetween, conduits connected to supply refrigerant liquid from said liquefying means to said evaporator, conduits providing an absorption solution circuit between said absorber and said generator, means for circulating absorption solution in said solution circuit, said refrigerant liquefier being positioned laterally of said absorber and having a portion thereof at the same elevation as a portion of said absorber.

28. In combination, a framework, absorption refrigeration apparatus supported upon said framework including a refrigerant generator, a refrigerant liquefier, an eva orator and an absorber, conduits interconnecting said generator,

liquefier, evaporator and absorber and providing an absorption solution circuit between the generator and absorber and an inert gas circuit between said evaporator and absorber, said evaporator, absorber and liquefier being positioned laterally of one another and each having a portion thereof in the same horizontal plane.

29. An absorption refrigeration apparatus including a refrigerant generator, an absorber and an evaporator, conduits interconnecting said generator, absorber and evaporator, and providing an inert gas circuit between the absorber and the evaporator and an absorption solution circuit between the generator and absorber, a motor operated gas circulator mounted within said inert gas circuit for circulating inert gas therethrough, said circulator including a gas impeller andv a motor armature connected thereto, a housing for said armature hermetically sealed to said'inert gas circuit, a partition separating said armature from said impeller and cooperating with said motor housing to provide a leak-proof lubricant chamber .therein, a lubricating medium in said chamber, and means for supplying absorption solution to said gas impeller to lubricate relatively moving parts thereof.

30. In combination, a cabinet having a heat insulated chamber and a refrigeration apparatus compartment, absorption refrigeration apparatus mounted within said cabinet and comprising a refrigerant generator, a condenser, an absorber. and a plurality of evaporator vessels, conduits providing an inert gas circuit between said evaporator vessels and said absorber, conduits providing an absorption'solution circuit between said generator and said absorber, said evaporator vessels each comprising a plurality of interconnected conduits located within a common plane, said a side wall of said insulated chamber, and means for dividing a stream of liquid refrigerant between said evaporator vessels. 7

31. In combination, a cabinet having a heat insulated compartment and a refrigeration apparatus chamber, absorption refrigeration apparatus within said cabinet including a refrigerant generator, a condenser, and an absorber in said apparatus chamber and a plurality of evaporator vessels in said heat insulated compartment, conduits providing an inert gas circuit between said evaporator vessels and said absorber, conduits providing an absorption solution circuit between said generator and said absorber, power operated means for circulating an inert gas through said inert gas circuit, means for dividing a stream of liquid refrigerant between said evaporator vessels, means within said evaporator vessels for forming a plurality of separate refrigerant liquid pools, and means for introducing inert gas into said refrigerant liquid pools as the gas flows through the evaporator vessels in counterflow to the refrigerant liquid.

. gas circuit between said evaporator and said absorber, a positive-displacement motor-operated pump in said inert gas circuit to circulate inert gas therethrough, said motor including a housing forming a part of said refrigeration apparatus and including a portion of magnetic material separated from the remainder of the apparatus by non-magnetic material, an armature within said housing opposite said magnetic material and a motor field structure outside said housing and opposite said armature, and means separating said armature housing from the remainder of the interior of the apparatus and serving to confine a body of lubricant to said armature housing.

33. In combination, an absorption refrigeration system containing an inert gas and having a re-- frigerant generator, an absorber, an evaporator and a condenser, conduits interconnecting the generator. absorber, evaporator and condenser to provide an absorption solution circuit between said generator and absorber, and an inert gas circuit between said evaporator and absorber, said generator and absorber being positioned at different elevations, a positive displacement gas circulating device within said inert gas circuit to circulate gas theretbrough under pressure, means for bubbling the circulating inert gas into absorption liquid in said absorption solution circuit to promote the circulation of said solution, means for bubbling the circulating inert gas into liquid refrigerant in said evaporator to agitate the liquid as it evaporates into the inert gas, and means for lubricating said gas circulator, said last named means including means for separating lubricant from the circulating inert gas before the gas is bubbled into liquid refrigerant in said evaporator and for returning separated lubricant to said gas circulator.

34. In combination, an absorptionrefrigeration system containing an inert gas and having a refrigerant generator. an absorber, an evaporator and a condenser, conduits interconnecting the generator, absorber, evaporator and condenser to provide an absorption solution circuit between said generator and absorber, and an inert gas circuit between said evaporator and absorber, a conduit for refrigerant liquid including a liquid evaporator vessels each being positioned adj cent trap connected between said condenser and evaporator, a positive displacement gas circulator hermetically sealed to said inert gas circuit to circulate gas therethrough under pressure, a gas and liquid separator in said gas circuit at a point between said circulator and said evaporator, said liquid trap being operative to shield said generator from the full efiect of the increased pressure in the evaporator due to said gas circulator, and means utilizing inert gas under pressure to control the flow of a liquid medium in said system.

35. 'In combination, an absorption refrigeration apparatus comprising a generator assembly, a condenser, an evaporator vessel, an absorber vessel, conduits interconnecting said generator, absorber, evaporator and condenser to provide an absorption solution circuit between said generator and absorber, an inert gas circuit between said absorber and evaporator, and a refrigerant medium circuit between said generator, condenser, evaporator and absorber, said' apparatus being charged with a refrigerant, an absorbent medium therefor and an inert gas, a power operated positive displacement gas pump in said inert gas circuit, said pump being hermetically sealed within said apparatus, said evaporator and absorber vessels being constructed to contain refrigerant liquid and liquid absorption solution respectively, and means exteriorly of said vessels cooperating with said pump to pass inert gas into liquid for one of said vessels to regulate the flow of said one liquid through a portion of said apparatus.

36. In combination, an absorption refrigeration apparatus comprising a generator assembly, a condenser, an evaporator vessel, an absorber vessel, conduits interconnecting said generator, absorber, evaporator and condenser to provide an absorption solution circuit between said generator and absorber, 'an inert gas circuit between said absorber and evaporator, and a refrigerant medium circuit between said generator, condenser, evaporator and absorber, said apparatus being charged with a refrigerant, an absorbent medium therefor and an inert gas, a power operated positive displacement gas pump in said inert gas circuit, said pump being hermetically sealed within said apparatus, said evaporator and absorber vessels being constructed to contain refrigerant liquid and absorption liquid respectively, means to commingle circulating inert gas with one of said liquids to cause intimate contact of the gas and the liquid, and means independent of said solution circuit and said inert gas circuit for conducting lubricating liquid to said gas 37. In combination, an absorption refrigeration apparatus comprising a generator assembly, a condenser, an evaporator vessel, an absorber vessel, conduits interconnecting said generator, absorber, evaporator and condenser to provide an absorption solution circuit between said gen-'- erator and absorber, an inert gas circuit between said absorber and evaporator, and a refrigerant medium circuit between said generator, condenser, evaporator and absorber, said apparatus being charged with a refrigerant, an absorbent medium therefor and an inert gas, a power operated positive displacement gas pump in said inert gas circuit, said pump being hermetically sealed within said apparatus, said evaporator and absorber vessels being constructed to contain refrigerant liquid and absorption liquid respectively during operation, means to bubble circulating inert gas into one of said liquids, means for supplying a liquid to the moving parts of said p p, and a saidzinert medium.

39. In combination, an absorption refrigeration apparatus including an evaporator, an absorber, means cooperating with said evaporator and absorber and providing an inert medium circuit therethrough, means for positively circulating inert medium through said circuit, means providing a closed circuit for a lubricating liquid for said circulating means, and a gas and liquid separating chamber, said lubricating liquid circuit including said inert medium circulating means, said separating chamber and a portion of said inert medium circuit.

40. In combination, an absorption refrigeration system including an evaporator vessel, an absorber vessel, conduit means for circulating an inert medium through said vessels, an inert medium circulator in said conduit means and positioned between the inert medium outlet of said absorber and the inert medium inlet to said evaporator, a gas and liquid separation chamber in said conduit means at a point between said circulator and said evaporator and operative to separate liquid present in the inert medium flowing to said evaporator, said system including means for returning liquid from said separation chamber to said inert medium circulator to lubricate the latter.

41. In combination, an absorption refrigeration system including an evaporator vessel, an absorber vessel, conduit means including a gas heat exchanger forming an inert gas circuit through said vessels, said circuit containing ammonia as a refrigerant medium and hydrogen as the inert gas, a positive displacement gas circuiator in said circuit at a point between the gas outlet of the absorber vessel and said heat exchanger, a gas and liquid separation chamber in said gas circuit between said circulator and said heat exchanger, said system including means for returning a liquid lubricating medium from said separationchamber to said gas circulator to lubricate the latter, the arrangement being such that the lubricating liquid cannot flow from the separation chamber to said evaporator under normal operating conditions.

42. In combination with an absorption refrigeration system of thetype having means providing a circuit for inert gas, a gas impeller housing having a gas inlet and a gas outlet interposed in said gas circuit, gas impeller means including an electro-magnetically driven element hermetically sealed within said housing, a drivingmeans located outside said housing operable to actuate said driven element and said gas impeller, means to supply a liquid lubricating medium to said impeller means, a gas and liquid separator means communicating with said gas outlet, means for conveying separated gas from said separator means, and means for returning separated liquid from said separator means to said lubricant supply means for said gas impeller.

43. In combination with an absorption refrigeration system of the type having means providing a circuit for inert gas, a gas impeller housing having a gas inlet and a gas outlet interposed in said gas circuit, gas imp'eller means for circulating the inert gas within said housing, electromagnetic means for actuating said impeller including adriving element and a driven element separated by a thin-walled portion of said housing, said driving element being located outside said housing, a gas and liquid separator in said,

gas circuit on the discharge side of said gas impeller, and means for returning liquid present in the gas discharged by said impeller and separated from the gas by said separator to said impeller housing.

44. A three-fluid absorption refrigeration apparatus comprising a plurality of vessels including a refrigerant generator, a condenser, an

evaporator and an absorber, conduits interconnecting said vessels and providing an inert gas circuit between the evaporator and absorber and an absorption solution circuit between the absorbet and the refrigerant generator, a plurality bf said vessels being arranged laterally of one another and so that a portion thereof is in the :same horizontal plane and so that the lowest liq- .and means utilizing hydrogen under pressure for elevating one of said liquids from one elevation to a higher elevation.

GEO. A. BRACE.

- 7 CERTIFICATE OF CORRECTION. Patent No. 2,2ho,17 April 29, 19in.

GEORGE A. BRACE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 8, sec

0nd column, line 10, claim ll, strike ont the words "to introduce the inert gas into absorption liquid and insert the same after "operative" in line 6, same claim; and that the said Letters-Patent should be read with this correction therein that the same may conformto the recordof the case in the -Patent Office.

Signed and sealed this Zhthday of June, A-. 1). 191m.

. Henry Van Arsdale, (Seal) Acting Comni-ssionercf Patente.

DISCLAIMER 2,240,178.Ge0rge A. Brace, Winnetka, I11. ABSORPTION REFRIGERATION. Patent I dated A ril 29, 1941. Disclaimer filed April 12, 1943, by the assignee, The

Hoover ompany. Hereby enters this disclaimer to claims 24 and 25 in said specification.

[Ofiicial Gazette May 4, 1943.]

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