US2522410A

US2522410A - Absorption refrigeration apparatus

Info

Publication number: US2522410A
Application number: US560216A
Authority: US
Inventors: Bank The National City
Original assignee: Servel Inc
Current assignee: Servel Inc
Priority date: 1944-10-25
Filing date: 1944-10-25
Publication date: 1950-09-12
Anticipated expiration: 1967-09-12

Description

Sept. 12, 1950 A. R. THOMAS 2,522,410

ABSORPTION REFRIGERATION APPARATUS Filed 001;. 25, 1944 Patented Sept. 12, 1950 ABSORPTION REFRIGERATION APPARATUS Albert R. Thomas, deceased, late of Evansville, Ind., by The National City Bank, administrator, Evansville, Ind., assignor to Serve], Inc., New York, N. Y., a corporation of Delaware Application October 25, 1944, Serial No 560,216

The present invention relates to improvements in valves and more particularly to an automatically operable check valve for permitting the flow of fluids in one direction while preventing the flow of fluids in the opposite direction.

While the valve of the present invention may have other uses it is particularly adapted for use in absorption refrigeration systems of the type illustrated and described in the application for United States Letters Patent of Albert R. Thomas, Serial No. 560,214, filed October 25. 1944, now Patent Number 2,518,202, dated August 8, 1950, and entitled Refrigeration." Systems of this type operate in a partial vacuum and utilize water as a refrigerant and a saline solution as an absorbent. In such refrigeration systems non-condensible gases may accumulate in the various elements thereof which interfere with the proper operation of the system. The noncondensible gases are usually purged from the system periodically by means of a vacuum pump or other suitable exhaustin means.

One of the objects of the present invention is to provide a valve of the type indicated between the refrigeration system and exhausting means to permit the flow of non-condensible gases from the system and prevent the flow of atmospheric air into the system.

Another object is to provide a valve of the type indicated which is automatically operable by slight differences in pressure at opposite sides thereof to open or close the same.

Still another object is to provide a valve of the type indicated having a flexible impervious diaphragm extending across the conduit and adapted to cooperate with the end of a by-pass tube connecting the conduit at opposite sides of the diaphragm.

These and other objects will become more apparent from the following description and drawings in which like reference characters denote like parts throughout the several views. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and not a definition of the limits of the invention, reference being had for this purpose to the appended claims. In the drawings:

Fig. 1 is a diagrammatic view of an absorption refrigeration system incorporating the automatically operable check valve of the present invention and showing the relationship of the valve with respect to the other elements of the system, and

Fig. 2 is an enlarged part sectional view of the valve.

6 Claims. (Cl. 62-5) The automatically operable check valve of the present invention is shown in Fig. 1 as applied to an absorption refrigeration system which operates in a partial vacuum. In such an absorption refrigeration system, liquid refrigerant such as, for example, water is introduced into the evaporator III from a condenser ll through a path of flow including a U-shaped tube II. The evaporator I0 is in the form of a horizontal cylindrical drum and the U-shaped tube II has one end connected to a sump It at the bottom of the condenser H with its opposite end extending upwardly through the bottom of the evaporator. Refrigerant vapor formed in the evaporator I 0 flows to an absorber H where it IS absorbed into a liquid absorbent suchas, for example, a concentrated water solution of lithium chloride, lithium bromide, or the like. The absorber It also is in the form of a horizontal cylindrical drum and is positioned directly below the evaporator It. A pipe I! extends upwardly from the top of the absorber it through the bottom of the evaporator l0 and for a considerable distance above the bottom to provide a stand-pipe in the evaporator. The stand-pipe I5 is adapted to exhaust refrigerant vapor from the evaporator It to the absorber it while malntairging a body of liquid refrigerant in the evapora r.

The absorption liquid enriched with refrigerant, or, in other words, the dilute salt solution, is conducted from the absorber It to the base of a generator It in a path of flow including conduit ll, pump I8, conduits i9 and 20, liquid heat exchanger 2|, and conduit 22. Within the generator is are disposed a plurality of riser tubes 23 enclosed in a chamber formed by an outer shell 24 and to which steam is supplied through a conduit 25 from a suitable source of supply. The flow of steam through the conduit 25 is controlled by a modulating valve 26 operated by a suitable servo-motor 66 responsive to variations in the resistance 62 of an electric circuit 65. Preferably the steam chamber in the generator I6 is provided with an outlet vent 21 adjacent its upper end and a condensate return line 28 adjacent the base thereof. The heating of the riser tubes 23 by the steam causes refrigerant vapor to be expelled from the absorp tion solution and such expelled vapor is effective to raise the absorption solution by gas or vapor-lift action.

The expelled vapor passes from the upper ends of theriser tubes 23 into the vapor separator 2| and thence flows through a conduit 30 to the condenser I I where the vapor is liquefied. Liquid refrigerant formed in condenser I I flows through the U-shaped tube I2 to the evaporator In, as explained above, to complete the refrigeration cycle. The raised absorption solution from which refrigerant vapor has been expelled is conducted from the upper part of thegenerator I6 promote absorption of the refrigerant vapor.

The heat liberated by the absorption of the refrigerant vapor in absorber I4 is transferred to a cooling medium suchgas, for example, water, which flows upwardly through vertically disposed banks of pipes 36 in the absorber. The cooling water is introduced into the lower ends of the banks of pipes 36 from a supply main. 31 and is discharged from the upper ends of the banks of pipes through a conduit 38. The conduit 38 is connected to condenser II sothat the cooling water also may be utilized to effect cooling of the condenser. The cooling water is discharged from the condenser II through a conduit 39.

The system operates in a partial vacuum with generator l6. and condenser II operating at one pressure and evaporator I and absorber I4 operating at a lower pressure. The pressure differential between the high and low pressure sides of the system is maintained by a liquid column in the up-leg of the U-shaped tube I2 between the condenser II and evaporator. I0; a liquid column'in the conduit 34 connecting the absorber I4 and heat exchanger 2 I and by the pump I9 connecting the conduits l1 and 20 between the absorber I4 and generator I6.

The liquid refrigerant in the evaporator I0 is circulated continuously in a loop-circuit to adapt the system to refrigerate at a place remote from the evaporator. The loop-circuit comprises a conduit 42, pump 43, conduit 44, cooling element 45 and conduit 46. The conduit 42 has one end extending into a sump 41 at the bottom of the evaporator II] to receive liquid refrigerant and its opposite end is connected to the inlet port of the pump 43. The conduit 44 is connected between the outlet from the pump 43 to the inlet of the cooling-element 45 and the conduit 46 is connected between the outlet from the cooling element to the upper part of the evaporator Ill. The cooling element 45 is illustrateddiagrammatically as a coil but it will be understood that this element may have other forms such as a radiator, or thelike, depending upon the particular installation. As illustrated in Fig. 1

4 stand-pipe I5 toprevent the liquid refrigerant from beingswept into the stand-pipe with the reirigerantvapor...

also iscirculated continuouslythrough an auxiliary loop circuit to promote absorption of the re- 4 frigerant vapor. The auxiliary loop circuit for the absorption solution comprises the conduit I1, pump I8, and conduit I9. One'end of the conduit I1 extends into a sump 54 in the bottom of the absorber I4 and the lower end of the conduit is connected to the inlet port of the pump I8. The conduit I9 is connected at one end tothe outlet port of the pump I8 and its opposite. end 52 extends horizontally into the upper part of the absorber I4 throughout substantially the entire length of the latter. The horizontally extending portion '52 of the conduit I9 is provided with a plurality of spray heads 55 each of which comprises a nozzle and a conical deflecting plate for dividing the absorption solution into a spray and distributing the spray over the banks of f of the 'draw'rfig "theioutletendioithecondfiiflL :ex'tends into"the evaporator! and isiprovided cooling pipes 36 to promote absorption of the refrigerant. During operation of the refrigeration system part of the circulating absorption solution is diverted from the conduit I9 through the conduit 20 and heat exchanger 2] to the generator I6 as previously described.

To prevent the progressive concentration of the absorption solution under certain conditions of operation and the crystallization and precipitation of salt resulting from such progressive concentration a control means is provided which is responsive to the concentration of the absorption solution and connected to adjust the valve 26 to regulate the amount of steam supplied to the generator I6. The control means may be located in any part of the refrigeration system where the progressive concentration of the absorption solution is likely to occur. As illustrated in Fig. 1 of the drawings a control float 51 is located in the chamber 32 in the return line between the generator I6 and heat exchanger 2I. The float 51 has a specific gravity such as to adapt it to rise when the concentration of the absorption solution has a predetermined 'value. The concentration control float 51 has an arm 58 extending outwardly from the chamber 32 through a flexible bellows 59 to permit relative movement and the arm is pivoted at 60. The flexible bellows 59 acts as a load spring opposing movement of the float 51 so that arm 58 has a movement proportional to changes in the specific gravity or concentration of the solution.

The outer end of the float arm 58 constitutes a movable contact SI for varying the resistance 62 of the electric circuit 65 for servo-motor 66. Thus, the servo-motor 66 is operated upon movement of the float 51 to adjust the valve 26 to regulate the flow of steam to the generator I6 in accordance with variations in the concentration of the absorption solution. Preferably a baffle plate 61 is provided in the chamber 32 adjacent the end of the conduit 3| to prevent the velocity of the stream of incoming absorption solution from affecting the operation of the control float 51. The end of the conduit 33 extends upwardly in the chamber.. ,32. above the. control float 51 to insure immersion of the floatby the I absorption solution.

' 1 Tina absorptionisolutiormin'Jheiabsorber-1:

Preferably an overflow by-pass 68 is provided between the separating chamber 29 of the generator I6 and the bottom of-the absorber I4. As illustrated in Fig. 1 of the. drawings. the upper end of. the overflow by-pass. 68.is protected by a baflie 69 and its opposite end is in the form of a vertical riser 10 to maintain a column of liquid absorbent for balancing the difference in pressure; betweerrthe: generatonii andlabsorberti A portion of the absorption solution circulatin: in the auxiliary loop circuit is utilized to withdraw non-condensible gases from the absorber It. The absorption solution is diverted from the conduit ll of the auxiliary loop circuit through a conduit II to a Venturl tube 18 which, in turn, is connected to a separating chamber H by a conduit 15. A conduit 18 connects the separating chamber I4 to the top of the absorber ll, see

Fig. 1. Connected to the Venturi tube 18 adjacent its constricted throat is a conduit 'll havin its opposite end extending into the absorber It to a position where the non-condensible gases accumulate. Due to the flow of the absorption fluid through the throat of the Venturi tube I3 the area adjacent the throat is evacuated which draws the non-condensible gases through the conduit H. The non-condensible gases drawn into the Venturi tube 13 are entrained in the absorption solution and carried into the separating chamber I4. As illustrated in the drawings a baille plate 18 is provided in the separating chamber 14 to prevent the non-condensible gases from entering the conduit 18. Extending upwardly from the top of the separating chamber I4 is a conduit 19 which is connected at its upper end to a float chamber 88. The float chamber 89, in turn, is connected to one side 9| of a valve chamber by means of a connecting conduit 82, see Fig. 2'. The opposite side 83 of the valve chamber is connected to a water operated aspirator 84 by means of a conduit 85. Water is supplied to the aspirator 84 from the supply main 31 through the pipe 88 and the water is discharged from the aspirator through a discharge tube 81.

In accordance with the present invention a novel form of automatically operable check valve 99 is provided in the path of flow of the noncondensible gases between the refrigeration system and the aspirator 84 which permits the flow of the gases therethrough while preventing the flow of atmospheric air into the system. The check valve 89 comprises a flexible impervious diaphragm 99 extending across the valve chamber to hermetically seal the side 8| from the side 83 and a by-pass conduit or tube 9| ex)- tending from the side 8| of the chamber to the conduit 85. The inner end 92 of the by-pass tube 9| is positioned adjacent the flexible diaphragm 90 and constitutes a valve seat adapted to be engaged by the diaphragm to close the conduit. Preferably a resilient valve plate 93 of a suitable synthetic rubber or the like is mounted on the diaphragm for engagement with thevalve seat at the end 92 of the by-pass tube 9|.

The flexible diaphragm 90 normally engages the valve plate 93 withthe end 92 of the by-pass tube 9| with a slight initial pressure to seal the side 8| of the valve chamber from the atmosphere. The side 83 of the valve chamber is subjected to the pressure in the conduit 85 to maintain the valve plate 93 engaged with the valve seat at the end of the by-pass tube 9|. Thus, if the pressure in the conduit 85 and side 83 of the valve chamber is the same or greater than the pressure in the side 8| of the chamber the valve plate 93 is flrmly engaged with the end 92 of the by-pass tube 9| to seal the refrigeration system from the atmosphere. However, when the aspirator 84 evacuates the conduit 85 and side 83 of the valve chamber t a pressure below that prevailing in the side 8| of the chamber the diaphragm 90 will be flexed to the dash line position illustrated in Fig. 2 to open the end 92 of the by-pass 9| and permit the non-condensible gases to escape therethrough to the condult 85.

one form of the invention having now been described in detail the mode of operation of the apparatus is explained as follows:

For purposes of illustration let it be assumed that the system is not operating and that the concentration control float 51 is in the position illustrated in Fig. 1 of the drawings. To initiate operation of the refrigeration system steam is supplied through the conduit 25 to the generator I8 and water is supplied from the main 81 to the cooling coils 39 in the absorber l4 and through the conduit 38 to the condenser Bimultaneously operation of the pumps l8 and 48 is initiated to circulate refrigerant and absorption solution in their respective loop circuits. With the float 51 in the position illustrated in Fig. 1 the valve 26 will be adjusted to supply steam to the generator It for full load conditions. The steam in the generator l8 vaporizes water from the absorption solution standing in the riser tubes 23 and the water vapor willrise in the tubes to the vapor separating chamber 29 and will raise the concentrated absorption solution from which the water has been expelled by vapor-lift action.

The refrigerant vapor will pass throu h the conduit 39 and the condenser II where the vapor will be liquefied by its contact with the relatively cold tubes therein. The liquid refrigerant in the condenser M then will flow by gravity into the sump l3 and through the U-shaped tube l2 to the evaporator Ill.

The liquid refrigerant delivered to the evaporator Ill will accumulate therein around the stand pipe l5 and will be continuously circulated through the auxiliary loop circuit by the pump 43. The vaporized refrigerant in the, evaporator ||l will flow through the stand pipe IE to the absorber H where it will be absorbed in the absorption solution delivered to the absorber from the separating chamber 29 through a path of flow comprising the conduit 3|, chamber 32, conduit 33, heat exchanger 2|, conduit 34 and spray pipe 35. To promote absorption the absorption solution will be continuously circulated through its auxiliary loop circuit by the pump l8. A portion of the absorption solution circulating in the auxiliary loop circuit will be diverted continuously through the conduit 29, heat exchanger 2| and conduit 22 to the base of the generator l8 to complete the refrigeration cycle. The absorption solution flowing from the absorber I4 is comparatively 0001 while the concentrated absorption solution flowing from the vapor separator 29 to the absorber I4 is relatively hot. As these two streams of absorption solution pass each other during their flow in separate paths through the heat exchanger 2| the dilute solution flowing to the generator l6 from the absorber M will be heated by the concentrated solution flowing to the absorber from the generator.

The float 51 in the chamber 32 moves in response to changes in the specific gravity or concentration of the absorption solution to continually adjust the valve 26 to control the amount of steam flowing to the generator. Thus, 11' the absorption solution becomes too concentrated, less steam will be supplied to the generator l6 until the concentration becomes more dilute at which time more steam will be supplied to the generator. Thus, the modulating control valve 26 will operate continuously to maintain the proper concentration of absorption solution in the system.

. and side 83 of the valve chamber.

A portion of the absorption solution circulating in the auxiliary loop circuit will be fed continuously through the conduit II to the Venturi tube 13. The flow of absorption solution through the constricted throat of the Venturi tube I3 will evacuate the area adjacent the throat and withdraw non-condensible gases; from the absorber I through the conduit 11, The non-condensible gases drawn into the Venturi tube 13 through the conduit 11 will be entrained in the absorption solution and delivered through the conduit 15 to the separating chamber 14. The absorption solution in the separating chamber I4 will flow through the conduit 16 back to the top of the absorber-ll. As the point of connection of the conduit 16 with the separating chamber .14 is positioned above the lower end of the conduit 15 the non-condensible gases will bubble upwardly through the absorption solution which. operates to strip any refrigerant therefrom. The non-condensible gases bubblingupwardly through the absorption liquid will accumulate in the riser tube or conduit", float'chamber 88, conduit 82 and side H of the valve chamber and displace any absorption liquid therein.

The non-condensible gases will be withdrawn continuously from the system by the water-operated aspirator 84. Water supplied to the aspirator 84 from the supply main 3'! through the conduit 88 and passing through a constricted pressure in the side 83 of the valve chamber is less than the pressure in the side 8| the diaphragm 90 will flexautomatically from the full line position to the dash line position illustrated in Fig. 2 to withdraw the valve plate 93 from the end 92 of the by-pass conduit 9| constituting a valve seat. The non-condensible gases in the side 8| of the valve chamber then will flow from the system through the by-pass conduit 9| to the conduit 85 and will be exhausted by the aspirator 84. If for any reason the pressure in the side 83 of the valve chamber increases above the pressure in the side 8| the resultant pressure on the flexible diaphragm 90 will flex it to the full line position illustrated in Fig. 2 to engage the valve plate 93 with the end 92 of the by-pass tube 9i and seal the refrigeration system from the atmosphere. Preferably the valve plate 93 will be engaged with the end 92 of the by-pass tube 9| with a slight initial pressure due to the inherent resiliency of the diaphragm so that the by-pass tube will be closed when the pressure in the side 83 of the valve chamber is slightly below the pressure in the refrigeration system to be sure that atmospheric air does not enter the system.

It will now be observed from the foregoing specification that the present invention provides a check valve of novel construction arranged be- When the tween the absorber and vacuunnpump whichmp: crates automatically to permit non-condensible gases to be withdrawn from the system while preventing the flow of atmospheric air into the systern. the present invention is automatically operable by the difference in pressure occurring at oppoparentsto those" skilledimtheearnlthatitheivalyear -7 may be applied to other systems and may have other uses than that herein shown and described.

It will also be observedthat the valve of j It will also be apparent that various modifications and changes may be made in the construction and arrangement ofthe parts of the valve without departing from the spirit and scope of the invention.

What is claimed is: v r

, 1. In an absorption refrigeration system having a plurality of elements interconnected to provide a closed circuit for the circulation of refrigerant and absorption solution, exhausting means, a conduit connecting the exhausting means to one of the elements of the system to withdraw non-condensible gases therefrom, valve means between the refrigeration system and exhausting means for opening and closing the conduit to the flow of non-'condensible gases, and a flexible diaphragm for operating the valve means, said diaphragm having its opposite sides subjected to the pressures occurring at opposite sides of the valve whereby to close the valve when the pressure on the exhaust side thereof is the same or greater than the pressure in the refrigeration system and to open the valve when the pressure on the exhaust side thereof is less than the pressure in the refrigeration system. I

2. In an absorption refrigeration system hav-- ing a plurality of'elements interconnected to provide a closed circuit for the circulation of refrigerant and absorption solution, exhausting means, a conduit connecting the exhausting means to one of the elements of the system to withdraw non-condensible gases therefrom, an automatically operable check valve in the conduit comprising a valve seat and a movable valve plate, a flexible diaphragm mounting the valve plate, and means for subjecting the opposite sides of the diaphragm to the pressure prevailing at opposite sides of the valve whereby to close the valve when the pressure on the exhaust side thereof is the same or greater than the pressure in the system and to open the valve when the pressure on the exhaust side thereof is less than the pressure in the system.

3. In an absorption refrigeration system having a plurality of elements interconnected to provide a closed circuit for the circulation of refrigerant and absorption solution, exhausting means, a conduit connecting the exhausting means to one of the elements of the system to withdraw non-condensible gases therefrom, said conduit comprising a chamber, a flexible impervious diaphragm extending across the chamber, and a by-pass connecting the chamber at oppositesides of the diaphragm, said diaphragm cooperating with the by-pass to close the latter when the pressure on the exhaust side of the diaphragm is the same or greater than the pressure in the refrigeration system.

4. In an absorption refrigeration system having a plurality of elements interconnected to provide a closed circuit for the circulation of refrigerant and absorption solution,:e'xhausting means, V a conduit including a chamber connecting the exhausting means to one of the elements of the system to withdraw non-condensible gases therefrom, a flexibleimpervious diaphragm extending across the chamber, and a by-pass connecting the chamber at oppositesides of thediaphragm, one 8 end of the by-pass being so arranged as to be engaged by the diaphragm to prevent the flow of gases and to flex away from the end of the by-pass to permit theflow ofegaseatherethroughe. 5 .Im'ansabsorptiomrefrigeration wsystem: hay:-

ing a plurality of elements interconnected to provide a' closed clrcuit'iorthe circulation of refrigerant and absorption solution, exhausting means, a conduit connecting the exhausting means to one of the elements of the system to withdraw non-condensible gases therefrom comprising a chamber, a flexible impervious diaphragm extending across the chamber, conduit sections connecting the chamber at opposite sides of the diaphragm to the exhausting means and element respectively, and a by-pass tube having one end connected to the conduit section between the diaphragm and exhausting means and its opposite end extending into the conduit section between the diaphragm and element to provide a valve seat adjacent the diaphragm, said diaphragm being engageable with the valve seat at the end of the by-pass tube to close the latter and operable by the difference in pressure at opposite sides thereof to flex away from the end of the valve seat to open the by-pass.

6. In an absorption refrigeration system hav- 20 ing a plurality of elements interconnected to provide a closed circuit for the circulation of refrigerant and absorption solution, exhausting means, a conduit connecting the exhausting means to one of the elements of the system to withdraw non-condensible gases therefrom comprising a chamber, a flexible impervious diaphragm extending across the chamber, conduit sections connecting the chamber at opposite sides of the diaphragm to the exhausting means and element respectively, and a by-pass having one end connected to the conduit section between the diaphragm and exhausting means and its opposite end extending into the conduit section between 10 the diaphragm and element of the system to provide a valve seat adjacent the diaphragm, and a valve plate mounted on said diaphragm, said diaphragm being operable by a difference in pressure at opposite sides thereof for engaging the valve plate with the valve seat to close the bypass or flexing away from the end of the valve seat to open the by-pass.

THE NATIONAL CITY BANK, Administrator of the Estate of Albert R. Thomal,

Deceased.

By JOHN N. EMIG,

Vice President.

REFERENCES CITED The following references are ofrecord in the file of this patent:

UNITED STATES PATENTS Number Name Date 973,609 Abrams Oct. 25, 1910 1,162,731 Burke Nov. 30, 1915 1,212,244 Olson et al Jan. 16, 191'! 1,909,076 Schlumbohm May 16, 1933 2,344,245 Grossman Mar. 14, 1944 2,353,859 Thomas July 18, 1944 2,363,381 Anderson Nov. 21, 1944 2,363,440 Roswell Nov. 21, 1944 2,470,756 Berestnefi May 24, 1949 FOREIGN PATENTS Number Country Date 387,028 Great Britain Feb. 2, 1933