US1861075A - Intermittent absorption refrigerating apparatus - Google Patents

Description

y 31, 1932- E. E. ALLYNE ET AL V 5 INTERMITTENT ABSORPTION REFRIGERATING APPARATUS Filed Jan. 19, 1928 g zgM/K M 0 Mu attozwug Patented May 31, 1932 UNITED STATES PATENT OFFICE.

EDMUND E. ALLYNE, OF CLEVELAND HEIGHTS, AND ALBERT C. SCHIOKLER, OF CLEVE- LAND, OHIO, ASSIGNORS TO THE ALLYNE REFRIGERATION CORPORATION, OF CLEVE- LAND, OHIO, A CORPORATION or OHIO INTEBMITTEN T ABSORPTION REFRIGERATING- APPARATUS Application filed January 19, 1928. Serial No. 247,951.

This invention relates tointermittentabsorption type refrigerating systems in which a suitable refrigerant, such as ammonia, is driven off from a suitable absorbing agent, such as water, densed and collected as a liquid in an evaporator, from'which, upon cessation of the boiling operation, it is returned to the boiler or still as a gas and is there absorbed in the absorbing agent, pending repetition of the cycle. In such systems, absorption and return of the gas are accompanied by drops in both pressure and temperature, and the refrigerating effect is produced and to some extent is controlled in accordance with the rate of cooling of the absorbing agent, for which purpose means is sometimes provided for circulating the absorbing agent from the boiler through a cooling loop to a cooler or radiator and then back again, so that'in its circuit through this path its temperature is lowered, its absorbing ability is increased, and the return flow of gas is continued and promoted.

Some difficulty has been experienced with the initiation and the continued production of absorption under stable conditions, especially When such a cooling loop is utilized for cooling the absorbing agent.

The present invention has for its object to provide an intermittent absorption system provided with a cooling loop for the absorbing agent, which loop is of multiple form x in the sense that it has two or more branches cooperatively related, bift of which one only,

or at times both, may function, according to changes in conditions, all for a number of important purposes. One object of this arrangement is to secure unimpeded flow through the loop or loops of both the absorbing agent and the gas being returned thereto. Another object is to secure the possibility of using two loops or loop portions of different capacities, one of which is particularly effective in initiating circulation of absorbing agent and the other of which later augments the flow of the absorbing agent and takes care of maximum conditions. Still another object isto enable the gas and absorbing agent to be introduced to the boiler at a by a boiling operation, is conplurality of points with an increased distribution thereof and the ability to increase agitation in the boiler and promote absorption. Another object is to provide an arrangement which does away with the tendency in a single loop system to return the gas to the boiler more rapidly than it can be absorbed therein with the likelihood of building up undersirable pressure in the boiler above the absorbing agent therein and thereby creating, in effect, a sort of back pressure which materially retards and sometimes stops useful and effective return of the gas to the boiler by so delaying or impeding the action that the refrigerating eflect is intion is to provide an arrangement of this kind in which the absorbing process is carried out under conditions where the action is more or less self-governing, in the sense that while return flow is sufficiently free and unimpeded to secure a rate of absorption necessar for efficient refrigeration, nevertheless un esirably excessive or too rapid return flow is prevented and the action is more or -.less gradual, doing away with the necessity for any special device to avoid blowing the trap or traps and enabling the still to be protected by a water instead of a mercury or like seal or trap, thereby reducing the cost and simplifying-construction and operation. i Another object of the invention is to so arrange the cooling loop or loops, particularly where they return the gas and liquid to the boiler, as to break up the surface of the ab sorbing agent in the still and positively insure not only the initiation of the absorbing operation, but also its continuance.

Further objects of the invention are in part obvious and in part will appear more in detail hereinafter.

In the drawings, which represent one suitable embodiment of the invention, Fig. 1 is a more or less diagrammatic front elevation, some parts being broken away and in section to expose other parts; Fig. 2 is a similar diagrammatic sectional elevation on approxidetail view of a modification. a

The system shown in the drawings comprises a boiler or still 1, shown as a cylindrical tank or vessel in which the refrigerant is The gaseous refrigerant passes off from the top of the still by way of a fairly large conduit 3 with a fairly high return bend leading down to the trap 4, wherein is a water seal formed by the absorbing agent. A part of the conduit 3 may be water jacketed, as at 5, and thus cooled to serve as a rectifier, permitting a large proportion of any absorbing agent which may be carried over with the gas to condense and drain to the trap 4, from which it finds its way back to the still.

The normal level of liquid in the trap 4 is at about the line A, and the pipe 3 extends downwardly into said trap nearly to its bottom' where its end is open, as at 6. The trap is also providedwith an outlet at the level A to a return pipe 7, which is of fairly large capacity and slopes downwardly to return gas or liquid, as the case may be, from the trap 4 to the still 1. Specifically the pipe 7 returns the gas and liquid conducted thereby to the cooling loop for the absorbing agent, as will later appear.

The trap 4 is also provided with a gas exit serving during the boiling operation to carry the refrigerant to the evaporator. Such exit is provided by the pipe 8 extending upwardly into the trap from its bottom and having itsend open at a high level therein, as at 8a. In

the other direction the pipe 8 communicates with a condenser, shown as coil 9, immersed in cooling water in a tank 10. The other end of the condenser communicates by a pipe 11 with the evaporator, which includes a tank 12 serving as a reservoir and from which the refrigerant flows by gravity to and through the cooling coil 13, at the bottom of which is a trap 14 with an outlet pipe 15 communicating with the pipe 11.

The evaporator unit, including the combined supply and return pipe 11, the pipe 15, the trapl, coil 13 and reservoir 12, are well known and require no detailed description. They may be of the form described and claimed in a co-pending application of Albert C. Schickler for liquid seal for absorption systems, Serial No. 218.280. filed September 8, 1927, to which reference may be had for a more complete description if desired. It is sufiicient to say that during the boiling operation the liquefied refrigerant is delivered by the pipe-11 into the top of the evaporator, where a liquid column is supported by the mercury in the trap 14, but said trap is of such form that any weak liquor or absorbing agent which may be carried over to the evaporator is permitted to return past the trap 14 and flow through pipe 11 and by way of condenser 9, trap 4 and pipe 7 to the boiler. The gas produced by evaporation of the refrigerant in the evaporator leaves from its top by way of pipe 11 and likewise is returned to the boiler through pipe 7.

Now coming back to the boiler or still, the absorbing agent therein is cooled by permitting or causing circulation thereof through a cooling loop, and specifically, through a cooling loop of multiple form. Said loop, generally speaking, is of the form shown and described in a prior application of Albert C. Schickler, for refrigeratingsystem, Serial No. 202,721, filed June 30, 1927. It comprises a descending or down leg 20, of fairly; large cross-sectional area, terminating at its bottom in a sediment collecting sump or well 21.

From the lower part of the leg 20 two branch conduits 22 and 23.extcnd oii laterally and immediately begin to rise in generally parallel arrangement, extending toward the other end ofthe still on a gradual incline and terminating in discharge end portions 24, 25, which extend upwardly into the still and are suitably arranged to deliver the gas and absorbing agent to the still in a manner to produce agitation and interrupt or break up the surface of the absorbing agent so as to initiate and promote absorption. For example, as shown in Fig. 3, the discharge end of either or both of the loop portions may extend above the low level B of the absorbing agent in the boiler. Therefore, any liquid delivered to the boiler from the loop is fountained into the gas space and the discharge end of the loop may be provided with means for causing the liquid so fountained to cascade as it falls back into the absorbing agent in theboiler and therefore break it up and produce agitation. As shown in Fig. 3, therefore, the pipe may be provided with one or more rings or washers 50, varying in size, if desired, and spaced apart vertically. and over which the absorbing agent cascades in being delivered to the boiler.

A similar effect in the sense of interrupting the surface of the liquid and producing agitation in the boiler may be obtained by terminating the discharge end portions of the loops at approximately the low level of absorbing agentin the boiler. or just a little below it. so that the liquid delivered to the boiler is shot up through the relatively thin upper layer of absorbing agent in the boiler and breaks up its surface.

The two loop portions 23, are of different cross-sectional area. loop 22. for example, being the smaller and loop 23 the larger, and

more than two loops may be used if desired. Means is provided for cooling the loops but preferably without material cooling effe t upon the down leg 20. Any suitable cooling means may be employed. such as a water acket with circulating water, but in the form shown the tank 10 is of L-form in end elevation, as in Fig. 2, that part of its whichcon- I zontal extension 10a, the loop members 22,;

23 are immersed, but the down leg 20 is surrounded by a metal jacket or shield 26 which provides an open air space around said leg and prevents a cooling effect of the water upon it. This arrangement of L-shaped tank and still is particularly advantageous because of the saving in space and the ability to keep the cooler water at the bottom of the tank in its lateral extension and permit the hotter water to rise to the higher levels where it is still more or less effective upon the condenser coils. The loops 22, 23, however, are most efiiciently placed in the cooler zone.

Means is also provided for introducing into the lower ends of both of the loops 22, 23, a supply of the gas or liquid, or both, returned to the boiler by way of pipe 7. As illustrated said pipe extends downwardly to a fairly low level adjacent the loops 22 and 23, where it is provided with two branches, marked 7a, 76, both of more or less U-form, branch 7a entering the bottom of the loop 22 near its lower end, while the branch '7 b enters the bottom of the larger loop 23. Also, the two branches 7a, 7 b are so arranged that their lowermost 4 points lie at different levels and, as illustrated, the branch 7 b communicating with the large loop 23 is lower than the branch 7a which communicates with the small loop 22. The difference in level may be one or a few inches, according to size and proportions of a particular apparatus. Although it is not essential, the system also may be provided with a secondary liquid supply-for either or both of the loops 22, 23, but in the particular form illustrated, a. secondary liquid supply is provided for the small loop 22 alone. This secondary supply is a pipe 27 communicating at its lower end with the down leg 20 just above extending forwardly and 22 at a point beyond or in advance of the point where the branch 7 a communicates with said loop. The purpose of this secondary su ply pipe is to provide an additional supply 0 absorbing agent to the loop 22 in advance of the point where the gas is introduced to said pipe, so that the flowing gas produces a pumping or injector action to increase and continue circulation of absorbing agent. Beyond the pipe 27 the loop 22 may be enlarged, as at 22a, to increase its cooling capacity, be-

ing again reduced at its outlet into the boiler.

The operation is as follows: The boiling operation need not be further described in detail. Fundamentally it is similar to the boiling operation in all intermittent absorption systems. During boiling there is practically no circulation of liquid through the loop or loops, but the gas passes oil through the rectifier to trap 4, from which any excess absorbing agent returns to the still and from which the gas passes to the condenser and is there liquefied, and is then conducted to the evaporator. At the end of the boiling oper- F ation there may be a small quantity of liquefied refrigerant of relatively low specificgravity in the bottom of the condenser coil or in pipe 11: The pressure throughout the system is high, the temperature at the still is high, the temperature at the trap 4 is fairly high, and the temperature is reduced through the condenser and toward the evaporator.

As soon as the heat is shut off, there is a prompt drop in pressure and temperature, particularly at the boiler, with a tendency of flow from the evaporator toward the boiler.

The first effect is to discharge from the pipe.

8 into the trap 4 the small quantity of refrigerant remaining in the condenser and pipe 11 before referred to. Its temperature is immediately raised to that at the trap 4 and it is vaporized, exerting its pressure in all diwhich would otherwise be produced by cooling effect on loop leg 22 and the lack of coolingefiect on down leg 20. This initiates circulation of absorbing agent, but at first through the small loop 22 only. The operation proceeds with a series of gas bubbles alternating with slugs of absorbing agent flowing upwardly through loop 22. ing or injecting actionis produced at the far end of the secondary supply pipe 27, if it is used, where additional absorbing agent is drawn into the loop 22 and continues on its way through said loop to the still. The enlargement 22a increases the volume of liquid in loop 22 and affords additional loop cooling surface or area, but of course the rate of flow through the loop is more or less proportional to its minimum cross sectional area. At the discharge end of the loop the gas and liquid are either fountained directly into the still,

as in Fig. 3, or are shot up through a thin layer of the absorbing agent above the end of the outlet 24, but in any event in a manner to break upthe surface of the absorbing agent,

produce agitation and promote a prompt and A pumptravel upwardly 90 rections and causing a rise of liquid from 7 primary loop circulation through the small p 22 is initiated and causes absorption o with the production of a further dro pressure at the still, tending to cause the ow from the evaporator toward the still of additional gas vaporized in the evaporator.

The net eflect is to initiate absorption and promote it to the point where the demand for more gas by the absorbing agent at the still, or caused by the process of absorption therein, produces sufiicient fall in pressure at the still to exceed-the ability of the smaller branch 7a to supply a current of gas to the still, whereupon the liquid level in pipe bottom of the branch 7 b and causes the flow of gas vfrom pipe 7 into the larger loop 23. A like circulation of absorbing agent is now initiated and continues through the loop 28, and from this point on absorbing agent is circulated continuously through both loops, it being discharged by both of them into the still through their outlets 24, with the continuance of the production of the necessary agitation'in the still to secure quick absorption. In flowing through the loops 22, 23, the absorbing agent is cooled by the effect of the cooling water in tank 10. As a result, the temperature of the still and of the absorbing agent therein is gradually reduced, with accompan ing drop in pressure and the production o a refrigerating eifect at the evaporator.

It is possible to provide each of the loops or loop members 22, 23, with its own separate down leg 20, but, as shown in the drawings, we prefer to combine the down legs, or, in other words, to connect both loop members to the same down leg, chiefly for the reason that upward flow through either loop branch produces down flow in the leg 20. Therefore, during the initial action of the smaller loop 22 there is a down flow of hot liquor from the still into the leg 20 and as soon as the larger loop 23 comes into action this hot liquor flows through said loop and the cooling action is augmented, whereas if each loop had its separate down leg, the first operation of each loop would find in its down leg 20 a portion of absorbing agent already subjected somewhat to the effect of cooling water and hence not quite so ready to accept or absorb refrigerant as the hotter liquid of the still itself;

In practice, it has been found that a system such as that described will automatically go into action to produce and continue absorption upon cessation of the heat and that frost may be produced on the evaporator in the course of four or five minutes after the heat is shut off. Therefore, by proper proportioning, the system is positively intermittent with no delay, such as might interfere with efiiciency in refrigeration, and can be made to l produce refrigerating cycles of say twelve drops still further until finally it reaches the hours with intervening heating periods of thirty minutes.

One objection kind employing a single loop has been the apparent impossibility to properly proportion the cross sectional area of a single loop to take care of the widely varying conditions with which a system of this kind is confronted. Other things being equal, a cooling loop of small cross section has a tendency to permit the gas returning to the still to blow through the absorbing agent so rapidly and in such relatively large quantities as to in 7 effect build up a back pressure in the still above the absorbing agent and block and sometimes practically stop further absorption, whereas a single loop of large cross sec- -tional area permits the gas to come back so rapidly and in such large volume, with such a high rate of absorption, that very promptly all the liquid in the trap 4 is blown upwardly through the pipe 3 and discharged into the still, so that pressure is equalized and the system again becomes inoperative because of the inability to drive the gas down beneath the absorbing agent for absorption therein. Again, variations in temperature of the coolto preceding systems of this ing water have their effect upon the desirable cross sectional area of a single loop. For example, a loop of small cross sectional area might be satisfactory for relatively cold cooling water, but if -the temperature of the cooling water rises, as in summer, such a loop would be unsatisfactory because suificient gas would get through into the still unabsorbed to produce the same kind of back pressure and block the further admission of gas to the absorbing agent. Likewise, a loop of large cross sectional area might be satisfactory for relatively hot cooling water in summer, but if the temperature of the cooling water drops materially, as in winter, absorption would take place so rapidly at the still as to blow the trap 4 and again block the apparatus.

It is noteworthy that this system, employing the multiple loop, is dependable in operation, and will not block further absorption for any of the several reasonsjust mentioned. It is not violent in action. Indeed, its refrigerating cycle is initiated and is carried to the effective production and continuance of refrigeration so dependably that it is unnecessary to provide a high water leg or bend in the pipe 3, and nevertheless, the trap 4 may be of the water seal type without danger of blowing it. In other words, in an ordinary system, the loop 3 need go no higher than the evaporator 12, and specifically may be no more than two or three feet high. The trap 4 is located slightly above the still and in operation it is found that during absorption the returning gas delivered to and absorbed in the still flows so readily and is so uniformli absorbed that the trap 4 is not blown and t e liquid therein is not driven over through the rectifier and pipe 3 to the still. The de- 6. Refrigerating apparatus of the charvice is therefore safe and stable in operation acter specified in claim 3 in which said conand will not reach a dead condition in which duit has upper and lower branches communiall temperatures drop to atmospheric witheating with said loops, the loop connected to out refrigerating eifect. the upper branch being of smaller capacity ne important advantage of the use of a than the other loop. plurality of cooling loops is the ability to se- 7. Intermittent absorption refrigerating cure in a single apparatus the necessary reapparatus, includinga boiler absorber, means duction of loop size to force or compel the for cooling the absorbing agent therein, cominitiation of circulation of absorbing agent prising a circulating loop through which and at the same time secure surface capacity absorbing agent may be circulated to a coolto produce an efiicient cooling result. With ing medium, said loop having down and up single loop systems,-the size of the loop has legs, a conduit for supplying the returning been important from two divergent standgas to a low point in the up leg and said loop,

points. It was desirable to have a loop of and a secondary liquid supply conduit for so small cross-sectional area to be eifective to said loop, including a plpe communicating compel the circulation to start as soon as the at one end with the boiler and at its opposite heat was turned ofl, but a small loop later end communicating with the up leg of said failed f capacity and was inefiicient as a loop at a point in advance of the connection cooler after circulation had started, so that thereto of the return gas pipe. from the latter standpoint, it was desirable 8. Intermittent absorption refrigerating to have the loop of large cross section. With apparatus of the kind specified in claim 7, the present arrangement, the small loop funcincluding a supplemental cooling loop contions first to compel circulation to start, and nected in parallel with the first cooling loop when it has started, the resulting absorption and communicating with the gas return pipe inevitably brings the larger loop into action independently of said first loop. to supply additional capacity so that the ab- In testimony whereof we hereby afiix our sorbing agent circulates rapidly enough to signatures. produce eflicient refrigeration, but without EDMUND E. ALLYNE. any tendencyto blow the traps. ALBERT C. SCHICKLER.

hat we claim is:

1. Intermittent absorption refrigerating apparatus, including a boiler-absorber, and cooling means for the absorbing agent, comprising a plurality of circulating loops, each having both of its ends connected to the bottom of the boiler-absorber and extending out of the range of the heating device and through which the absorbing agent is circulated in parallel to a cooling medium and 5 means for setting up circulation from the boiler through said loops during the refrigerating cycle.

efrigerating apparatus of the kind specified in claim 1 in which said loops vary in capacity.

3. Intermittent absorption refrigerating apparatus, comprising a boiler-absorber, a condenser, and an evaporator connected in an operative cycle and including a conduit for returning the gas to the boiler-absorber, and a plurality of cooling loops each having both of its ends connected to the bottom of the boiler-absorber and extending out of the range of the heating device and for circulating the absorbing agent to a cooling medium, and connections from said gas return conduit to each of said loops.

4. Refrigerating apparatus of the character specified in claim 3 in which the loops 1 5 vary in capacity.

5. Refrigerating apparatus of the character specified in claim 3 in which the lower most parts of said return gas conduit portions lie at difierent levels.

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