US2339814A - Continuous absorption refrigerator - Google Patents

Description

J. N. ROTH CONTINUOUS ABSORPTION REFRIGERATOR Jan.' 25, 1944.

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Patented Jan. 25,

CONTINUOUS Ansonr'rr'on marineros. Joseph N, Both, neming, meh., assigner, by

Mic

ents, to .Gibson Refrigerator Cqmpany, Greenville, Mieli., t corporation of Application Maren 21, icio, sensi No. 326,292 Y s ,(cl. sz-si This invention relates to a continuous absorption refrigerator, and more particularly to@- improved means for effecting movement of liquor from the absorber tothe still in a refrigeration system adapted to maintain the still at a high pressure and the absorberv at a lew pressure. f One feature of this invention is that it provide's improved transfer means forrreturning rich liquor from the absorber to the still; another 'feature of this invention is that it provides more -quiet and more positive operation in a system of the type wherein the transfer chamber is at times at high still pressure and at times at a pressure as low or lower than the low pressure in the absorber; a. further feature of this inventio'n is that it provides positive movement of uid when desired withra simplified` valve arf rangement; yet another feature of lthis^lnvention Y is that it provides niean's'ffor dissipatlng heat which may be generated ,in the transfer chamber; and still another feature of this invention is4 that it provides a` considerably simplified structure accomplishing all of .the functions and advantages of refrigeration systems disclosed' and claimed in my earlier applications. Other v features -and advantages of this invention will be apparent from the following specicaton and the drawings, in which: Y Y Figure l is a schematic or diagrammatic showing Iof a continuousabsorption refrigerator-embodying my inventions; Figure 2 is a detail view, principally in vertical section, of the transfer chamber andfvalve mechanism; Figure 3 is a view, principally in vertical sectionrofl the valve mechanism shownin Figure 2, and at right angles to a showingin such view; and Figure-4 is a small fragmentary sectional view, similar to a portion of the valve mechanism shown in the valve plunger up in@ Figure' 2, but showing pthe open position. Y i In the particular embodiment ofmy invention described herewith, the s stem in general comv prises a still adapted to frigerant and absorbent, as ammonia and water, boiled therein by the application of heat; a con- V'denser connected by a vapor conduit to the still to liquefy the refrigerant vapor delivered thereby; an evaporator, or cooling unit ,in which the 4liquefied refrigerant' is permitted to vaporie, lthe evaporator having restricted connection with .the condenser: an absorber in which the Y gas from the evaporator is'rabsorbed in liquid';`

and means for effecting flow of weak liquor from the bottom of the still to the absorber and .flow

of rich liquor from the -bottom oLtlie absorber 55 ve a-mixture-of reo Y to the This latter means includes a trans` fer chamber intermediate the absorber and the still and various valves so arranged as to periodically eifectilow of liquid from the absorber tothe transfer chamber,'and from they Y transfer chamber to the still. Referring more particularly to a specific tem schematically -or diagrammatically illustrated in Figure 1, the still Il is adapted lto contain a mixture'of -water and ammonia. A flue Il is provided within the still and heat delivered thereto by the combustion of gas 'or some other fuel delivered by the'burner I2. An analyzer Ytower I3, in the for'mof a long cylindrical tubing enclosing the flue ll, rises from theV upper part of the still, which`is a vertical cylindrical vessel. Both the analyzer tower --and' the still i are provided with baille plates, as I4 and l5, these plates serving to stratlfy theliquid in the still and to improve the efficiency of the apparatus.

Rich ammonia vapors boiled of! the liquor in Y* the still pass upwardly through the analyzer tower ll and thenthrough the pipe connection I6 to the rectiiler l1., a finned inclined tube at the top of the system.. From therethe ammonia vapors, any entrained water vapo Yhaving been `-removed by the rectifier, pass down through the Y connection I8 to a congenser I9 at the lower endy of'the apparatus. This .condenser comprises one or more lops of piping, finned to increase the heat radiation. The ammonia vapor is here conldensed in to liquid ammonia, and then elevated by the vapor pressure behlndit through the conf nection 2li tothe ,receiver 2|. l

The amount -of ammonia boiled ofi and liquefied is a function.V of the concentration 'of v, the liquorin the stilland of the amount of heat supplied to it, so that if the concentration of liquor is kept relatively constant the rate of delivery of liquid ammonia to the receiver2l will be practically a direct function of the amountV Vof heat supplied to the still. The-amount of fuel delivered to the burner l2, and thus'the amount of heat supplied and the ratefof delivery of liquid ammonia te the receiver, can be regulated in any Vdesired manneras by a valve (not here shown) actuated in conventional-manner' by a thermostat in the cooling chamber of the refrigerator.

Liquid ammonia passes from the" receiver 2l' to the dry evaporator 22, preferably comprising several coils of piping.A throughthe restriction interposed by is valve 2: eontroned by the nos: 24. The iloatand valve are so arranged that; as more liquid ammonia is'dellv'ered teurere-' syssorber loop is provided, i

ceiver, the valveopens further to permit increased ilow to the evaporator to maintain the level of liquid in the receiver substantially constant.

Absorbing apparatus is provided in the form of anupper chamber or vessel 25 having extending downwardly therefrom a cooling and absorption loop. The .downward flow path is through a short pipe 25 to an annular jacket 21 around a transfer chamber, to be hereafter more fully described, then down through a pipe 28 to an absorber cooling coil 28, also finned for 'better heat radiation and preferably located, with the condenser, at the bottom of the cabinet in which the apparatus is housed. The flow path in this cooling and absorption loop is then brought back the absorber vessel 25 through the upwardly extending pipe 3Q, preferably terminating an inch `-or so above the 'normal level of liquid in the absorber chamber 25. .Y

Expanded ammonia vapor from the evaporator 22 passes through a pipe 3| into the rising. leg

30 of the absorber loop, near the lower end thereof. The incoming vapor creates bubbles in the leg 30 which provide a liquid lift or pump action 4insuring circulation of absorption liquid through the loop. Inasmuch as the liquid in this risingleg is weak liquor withdrawn from the bottom of the absorber vessel,v and cool as a result of passing through the iinned radiator 29, all absorption normally takes place in the pipe 38, enriched liquid flowing out of the top of this pipe into the absorber chamber 25.

yThe level of liquid in the absorber vessel is -maintained by a valve 3 2 controlled by a float 33, the valve 3 2 controlling il'ow of liquid from the end of the pipe 34. This pipe leads from the lower end of the still (where the liquor therein is weakest) through a heat exchanger indicated in general as 35, and then on up to open into the absorber vessel, the flow through th? pre v pipe 34 being controlled by the valve 82, as

viously mentioned.

The ymeans for returning rich liquor from the absorber to the still comprises as. its principal parts a transfer chamber 35, a valve assembly 31',

and associated connections to render the combination operativa/ The leg 30 of thel abunder the `absorber vessel 25, with a cylindrical jacket 38. A short cross tube 30a in communication with the pipe 3|, the cross tube having open ends. affords communication with this Jacket, and there is thus ailow path for rich liqui. from the absorber through the jacket 38 an `'pipe 39, past check valve 40, into the bottom of the'transfer chamber 3 5. 'I'his flowpath is controlled only by the checkvvalve 40, and thus whenever the transfer chamber pressure is equal to or lower than that in the absorber vessel there is a now of enriched liquid into the transfer chamber.

ing, and controlled' by the valve element therein,

`a. pipe 4| leading from the 'bottom 'of the transfer chamber 85; a vpille 42 leading from the top of the transfer chamber; and a pipe 43 connected to the'pipe I8 which is always filled with high pressure vapor. In addition, a pipe 44 has one a mixture of refrigerant and absorbent of sub-- stantlally the same concentration as tha which is intended to be the minimum concentra on in the still. Pressure generated in the thermostat bulb by the heat of the still -is transmitted through the liquid actuating leg 48 to the bottom of the valve housing, where it is applied to one side of a. Sylphon; still pressure, delivered to the valve housing through the pipe 41. jacket 45 and lpipe 44, is appliedl to the other side of theSylphon. When the concentration in the still has boiled down as much as is desired, therefore, Y

the pressure on the bulb side of the Sylphon exceeds that on the other side, and the valveactuating mechanism moves. The actuating mechanism preferably includes snap-acting means, so that thevalve element or plunger 49 moved by the actuating mechanism always stands in either upper or lower position; and never assumes any intermediate position.

As may be best seen in Figures 2 and 3, which vshow the valve plunger 49 in lower position, all

valve-controlled connections in the valve arrangement are closed in this position. That is, the ports in the valve cylinder 50 which are connected to the pipes 4I, 42 and 43 are all sealed or blocked by the valve 'element when it is in lower position. Under these conditions the transfer chamberis filled with liquid drawn from the rber.

When the concentration in the still has boiled down to the desired minimum, thepressure in the actuating bulb `exceeds the lstill pressure sufllciently to snap the valve plunger to upper position, as shown in Figure 4. In thisposition ports 42a and 43a, connected respectivelyl to pipes 42 and 43, are connected by an opening 5I drilled through the valve plunger; and port 4Ial is uncovered by the bottom of the plunger, so that there is a connection from the bottom of the transfer chamber through the pipe 4I, the

valve housing, the pipe 44, the heat exchanger 35, the `iacket 45, and the pipe 41 into the still. 1 Initsmuch as high pressure vapor isbeing deliv-y ered to the top of\ the transfer chamber at this time, and the transfer` chamber is located at a. level higher than the still, liquid in it siphons up through the pipe 4I and passes to the still. In doing so it passes through the jacket surrounding the thermostat bulb, and rather rapidly co'ols the bulb. In a very brief interval, therefore, generally less than a minute, the valve snaps back .to closed position. This is preferably designed to occur when only about two-thirds of the liquid in -the transfer chamber has been moved to the still. The oat 52 separates the vapor from the liquid in the transfer chamber during this operation to prevent undesired absoption. Y

A connection is provided lietweenthe weak a `liquor supply pipe 34 and the top of the trans- 'I'he valve device 3l has .opening into its hous- Y passes through the top'ofv th'e transfer chamber.

As soon as the 'valve has' moved to lower or closed ,A position. however, no more vapor ows into the end opening into the valve housing, thii Dipe- 4 passing through the heat exchanger 35, tl'iough a et 45`around a thermostat bulb'in'the s and` then up through a pipe 41 to open Y into the analyzer tower I 8 ashort distance above` the still proper.`

tcp of the transfer chamber through the pipe 42;. and 'the absorption? of this vapor by the iine stream of weak liquor entering thetop of the transfer chamber redu the pressure in that chamber. The pressurcdrops rather rapidl, going even belowthe pressure in the absorber vesse 25. .l Normally, the. absorber would operate at about :fifteen pounds pressure. and the transferchamber pressure would drop, in a matter of seconds after connection to the still has been blocked, to several pounds less than this, Aas for example ten pounds. The difference inv heightv and pressure between the two chambers then opens the check valve 40 and causes a flow of liquid into the bottom of the transfer cham-v ber through the pipe 39. ,This continues until the transfer chamber is completely filled with liquid, whereupon the ne stream of weak liquor entering it immediately begins to raise the pressure, and. continues to do so until the pressure in the transfer chamber is substantially the same -as that in the still. The transfer chamber then stays in this condition, filledwith liquid and at high pressure until the still again calls for further rich liquor, generally in the neighborhood oi' seven or eight minutes later.

While the continuously operating absorption refrigeration system described herein contains a number of inventions and improvements over other known systems, -this present application is the system to the other. Moreover, the pressure in the transfer chamberis reduced from that of the high vside of the system until it is equal to or lower than thatin the low side before there is any now path between the absorber and the transfer chamber. A' simple check valve I0, g which can be vmade fool-proof and positive. is the only valve between. the transfer chamber and the low side of thev system; and except for a rather brief interval. it normally withstands the Vpressure drop between the high and low side of the' particularly concerned with the transfer chamber and valve arrangement. Other improvements in the system are the subject of my other copending joint and sole applications led both earlier and later than this application. One of the earlier is application, Serial No. 296,995, filed September 28, 1939; another is, application, ASe

rial No. 298,110, led October 5, 1939; and still another is application Serial No. 314,704, filed y January 19, 1940.

Continuously operated absorption refrigeration apparatus to maintain the still at high pressure and the absorber at low pressure and to return liquor to the still periodically by a transfer chamber and associated apparatus presents a Vnumber of problems, particularly when designed in4 asize appropriate for use as a domestic or household refrigerator. In .the first place, the pressure inthe high side of the system is frequently two hundred pounds per square inch or higher, while that on the low side of the system is-fgenerally about atmosphericl presslre;

Early work done on refrigeration -systems of general type by Ralph E. Schurtz, illustrated` in Patents Nos. 1,414,527@ 1,627,808, 1,796,410,

1,891,028, 1,890,531 and 1,905,308, switchedthe Y transfer chamber alternately from the high pressure to the low pressure side of the system. This was highly undesirable in a domestic refrigerator, because when the t ansfer chamber was switched from the highhe low side of the apparatus, both sides of the plunger valve normally having high pressure thereon. Since reduction in the pressure in the transfer chamber is effected by absorption therein, and generates heat, the jacket 21 and nned coil 29 provide means for .quickly and readily dissipating this heat. 4 i

While I have described and claimed certain embodiments of 'my inventicnit is to be understood that it is capable `of many modifications.`

Changes, therefore'. in the construction andfarrangement may be made without departing from as disclosed the spirit and scope of the invention in ,the appended claims.

.Iclaimz 1 Absorption refrigeration apparatus of the Azharactiddesciibed adapted to provide continous refrigerating effect, including: a still; a condenser; the `still and condenser being adapted to operate at high'ppressure; an evaporator; an. absorber, the evaporator andl absorber being adapted to operate at\low pressure; a transfer tion and absorber liquid flowing in the loop passes throughjthe portion in heat exchange relation before passing through the heat dissipatin'g portion. 3. Absorptionrefrigerationapparatus of the character described adapted to provide continuous refrigerating effect, including: a still; a condenser, the still andv condenser being adapted to operate at high pressure: an evaporator: an absorber, the evaporator and absorber being adapted to operate at low pressure; a transfer chamsystem the vapor vented vinto the low sidewith a highly objectionable loud hissing or rushing noise, andthere wassa considerable reduction in absorberemciency. Moreovenat all vtimes the v 'valve means had to withstand the complete pressure drop across the system, andv it is rather difficultto prevent leakage across a simple slide' valve maintaining a pressure difference in the neighborhood of two hundred pounds per square inch, particularly after. some wear.

These and other objections in earlier systems' ber for effecting return of liquor from the ab-vv sorber to the still; vaporand liquid connections between the chamber and the still; transfer valve means including valves controlling each of said connections, said valves being interconnected and of lthis type have been overcome by my present invention, and a very much'simplied valve arrangementachieved. f Instead of switching vtop,v

and bottom connections to various other pipes. th valve here only-opens or closes two-connecti ns or ow paths. There is a vapor ow path through the pipes 43 andf42,l and a liquid flow Path through the pipes Il and Il; and these are eitherppened together, or both blocked. There is no switching of connections fromone side of movable together to permit simultaneous flow in both connections for a period and simultaneously .block ow in both connections for a period; a 'u connection between the transfer chamber andthe absorbersincluding a check-valve preventing flow of fluid from the formerl to the latte'r; a conduit'-,

connecting the still direotlytothe transfer chamber to deliver weak liquor thereto; and control means for the transfer valvemeans; whereby the transfer chamber is reiled rapidly and-its pres- `sur'e'rises rapidly to that of the stilly to zriaintainV balanced pressures on the transfer valve meansl for' the major portion of' each transfer cycle.

U4. Absorption refrigeration apparatus 'of nel? character described adapted to provide continuous refrigerati'n's` effect, including: a still; a conf denser, the still and condenser Abeing adapted to operate athigh pressure; an evaporator; an

absorber, the evaporatorq and absorber being adapted to operate at low pressure; a transfer chamber for effecting Ireturn of liquor from th absorber to the still; vapor and liquid connections between the chamber and the still; transfer valve means including valves controlling each of said connections, said valves being interconnected and movable together to permit simultaneous iiow in both connections for a period and simultaneously block ilow in both connections for a period; a connection between the transfer i chamber andthe absorber 'including a checkvalve preventing flowI of fluid from the former to thejlatter; a conduit connecting the still directly to the transfer chamber to ldeliver Weak liquor thereto; and control means including a thermally responsive element in heat exchange relation with the contents of the still and conn'ected to the transfer valve means for shifting the latter in response to change in a condition in the still; whereby the transfer chamber is re` theretofore.

JOSEPH N. ROTH.

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