US1914687A - Liquid return for intermittent absorption refrigerators - Google Patents

Description

June 20, 1933. T. B. FOCKE 1,914,687

uouni RETURN FOR INTERMITTENT ABSORPTION REFRIGERATORS Filed Aug. 7, 1951 3 Sheets-Sheet 1 June 29, 1933. T B, FQCKE $14 6 87 LIQUID RETURN FOR INTERMITTENT ABSORPTION REFRIGERATORS Filed Aug. 7, 1931 3 Sheets-Sheet 2 June 20, 1933. 1-. B. FOCKE 1,914,687

LIQUID RETURN FOR INEERMITTENT ABSORPTION REFRIGERATORS Filed Aug. 7, 1931 3 Sheets-Sheet :s

Patented June 20, 1933 UNITED STATES PATENT OFFICE THEODORE B. FOCKE, OF CLEVELAND HEIGHTS, OHIO, ASSIGNOR TO PERFECTION STOVE COMPANY, OF CLEVELAND, OHIO, A COBPORATION OF OHIO LIQUID RETURN FOR INTERMITTENT ABSORPTION REFRIGERATORS Application filed August 7, 1931. Serial No. 555,771.

This invention relates to intermittent absorption refrigerators which, as is generally known, consist of a generator-absorber and a receiver-evaporator that are connected to gether by conduits, one of which has associated with it a condenser, the whole constituting a hermetically sealed system that contains a quantity of suitable refrigerant and a quantity of absorbent therefor, in proper proportions. The refrigerant may consist of ammonia, for example, and the absorbent, watefl and a suitable heating device is arranged in operative relation to the generatorabsorber.

In the operation of the apparatus, when the heating device is effective, the mixture in the generator-absorber boils and the refrigerant vapors pass to the condenser and the resultant anhydrous refrigerant liquid is conducted to the receiver-evaporator. This portion of the operation, known as the heating phase, continues until the required amount of refrigerant is distilled over into the receiverevaporator; and the heating of the generatorabsorber is then discontinued. Thereupon Y the pressure, which has risen to a considerable valueduring the heating period, falls, and the refrigerant in the receiver-evaporator evaporates and passes back in the form of gas to the generator-absorber to be absorbed by the weak liquor in the latter vessel.

Although a dehydrator is usually provided between the generator-absorber and the con denser for recovering absorbent vapors,

which pass with the refrigerant vapors from the generator-absorber, and condensing and returning them to the generator-absorber, it invariably happens that a certain amount of the absorbent is distilled over with the refrigerant into the receiver-evaporator; and if this were not removed at frequent intervals it would accumulate and soon materially reduce the efiiciency of the apparatus. 0 It is the purpose of the invention to provide simple, efiicient, and thoroughly reliable means for returning absorbent liquid that has accumulated in the receiver-evaporator during a heating period to the generatorabsorber before the next cycle of operation.

0 A further object is to provide means of this character that will function regardless of the relative elevated positions of the generatorabsorber and the receiver-evaporator. By virtue of certain embodiments of my invention, the generator-absorber may be at a higher or lower plane than the receiver-evaporator or in a common plane therewith.

Various embodiments of the invention are illustrated in the accompanying drawings,

frigerator incorporating my improved liquid return means; Fig. 2 is a similar View showmg a modification of the liquid return means, and Fig. 3 is a diagram of refrigeration apparatus incorporating a form of my liquid return means applicable only to a situation in which the generator-absorber is at a lower level than the receiver-evaporator.

Throughout the views, 1 designates the generator-absorber and 2 the receiver-evaporator. A vapor delivery conduit 3 leads from the upper portionof the generator-absorber to the lower portion of the receiver-evaporator, and, according to the present illustrative embodiment, a part of the conduit is in the form of a coil 3- which, with a tank 4 wherein it is enclosed, constitutes a condenser. The tank 4 contains a suitable quantityof cooling liquid, and the portion of the conduit 3, between the vertical branch that rises from the generator-absorber and where said conduit merges into the coil 3 is inclined upwardly toward the coil to provide a dehydrator desig; nated 3. A heating device 5, shown conven tionally as a gas burner, is located below and in operative relation to the generator-absorber -1.

Considering now the embodiment illustrated in Fig. 1, a gas return conduit 6 leads from the receiver-evaporator to the generator-absorber, and, in the latter vessel,it extends downwardly to a point below the minimum liquid level therein, while its opposite or receiving end dips into the receiver-evaporator to a point somewhat below the normal maximum liquid level in the last mentioned vessel, such level being indicated by the line x. A liquid return tube or conduit 7 extends from very near the bottom of the receiverevaporator upwardly through the top of said vessel and thence laterally and upwardly and joins the conduit (3 a short distance above the generator-absorber 1.

When the heating device 5 is in operation, the mixture of absorbent and refrigerant in the generator-absorber 1 boils and the vapors v thereof rise through the conduit 3, all or the greater part of the absorbent vapors condensing within the dehydrator portion 3 of the conduit and returning by gravity to the generator-absorber. The refrigerant vapors and such of the absorbent vapors as may have passed the dehydrator condense in the coil 3 and from there gravitate into the receiverevaporator 2, accumulating therein until the liquid level is approximately at the height indicated by the line a, at which time the heating device is rendered ineffective in any suitable way. During this heating period the pressure within the system rises to a relatively high value, and when the heat is discontinued the pressure within the system and especially within the generator-absorber 1 immediately starts to fall and thus creates a differential in the pressures prevailing in the generator-absorber and the receiver-evaporator, that in the former vessel abviously being the lower. Under the influence of the higher pressure in the receiver-evaporator, the liquid level therein is lowered and the displaced liquid rises within the conduits 3, 6 and 7. Inasmuch as the absorbent present in the receiver-evaporator is heavier than the refrigerant liquid it will collect within the bottom of the vessel and rise through the con duit 7. This action continues until the liquid level in the receiver-evaporator fallsbelow the inlet end of the conduit 6. Before this condition is reached, however, practically all of the absorbent liquid has been forced up into the conduit 7 to the discharging end of the conduit 6 and flows therethrough into the generator-absorber. When the receiving end of the conduit 6 becomes uncovered the liquid will recede from said conduit and the refrigerant gas will flow through it and will relieve the pressure sufficiently to prevent further liquid being forced into the conduit 7 and any liquid reposing within said conduit when this occurs will gravitate to the receiver-evaporator. It is essential that the conduit 6, or a part thereof, be at a materially higher elevation than the highest part of the conduit 7, firstly, because the return of the absorbent liquid should be effected before the refrigerant liquid reaches the highest point of the conduit 6 as otherwise it would pass such point and flow into the generator-absorber; and secondly, because the absorbent liquid is of greater specific gravity than the refrigerant liquid and consequently would maintain a lower elevation in the conduit'7 than the refrigerant liquid would in the conduit 6, under substantially the same propelling pressure.

Thus it will be seen that my invention provides a liquid return means for intermittent absorption refrigeration apparatus that effectively fulfills the purpose hereinbefore set forth.

The modification illustrated in Fig. 2 differs from that above described only in this: that the discharge end of the liquid return tube 7 opens into the top of the generatorabsorber 1 instead of joining the gas return conduit 6 or extending to a point below the liquid level in said vessel. The operation of this form of the invention will be readily understood from the foregoing description of the first form.

In the modification illustrated in Fig. 3, the generator-absorber 1 is below the plane of the receiver-ewiporator 2, and a single conduit 7" serves to return both absorbent liquid and refrigerant gas from the receivercvaporator to the generator-absorber, the con duit having a downwardly directed branch 7 that opens adjacent the bottom of the re- (-eiYer-evaporator, and a branch 6 that rises from the conduit 7 and is directed over and downwardly into the receiver-evaporator where it terminates a suitable distance below the maximum liquid level in said vessel.

In considering the operation of this form of the invention, which is substantially the same as that of the previously described embodiments, it may be explained that as the refrigerant condensate enters the receiverevaporator through the delivery conduit 3 the liquid will rise in the tube 7, the absorbent liquid rising first within the said tube because of its natural position about the open end thereof. Therefore, by the time the heating period ceases and the maximum amount of refrigerant has been distilled over into the receiver evaporator, the liquid level in the branch 6 will stand at substantially the same height as the liquid in the receiverevaporator while that in branch 7 will be somewhat lower due o its containing the heavier absorbent liquid; then when the cooling phase begins and the pressure within the receiver-evaporator forces the liquid upwardly into the branches 7 and 6*, that from the branch 7 will flow through the conduit 7" back to the generator-absorber 1 before the liquid in the branch 6 reaches the highest point of said branch. By the time the liquid closely approaches the high point of the last mentioned branch, the receiving end of said branch will have been uncovered by liquid and as a consequence thereof the pressure in the two ends of the system will equalize and the flow of liquid through the branch 7 will cease. Thereafter, the refrigerant gas duit 7 to the generator-absorber where it liquid from flowing through the gas return will be reabsorbed by the liquor therein.

I am aware that attempts of a nature somewhat similar to that of the present invention have been made in the past, as evidenced by I Letters Patent toLunburg No. 1,7 79,070 and mittent absorption type,

to Loetscher No. 1,222,642; but certain differences resulting in marked advantages distinguish my invention from its predecessors. Having thus described my invention, what I claim is:

1. In refrigeration apparatus of the intercommunicative means leading from the receiver-e-vapora-tor to the generator absorber, said means involving two conduits, one that leads from anabsorbent liquid collecting portion of the receiver-evaporator and the other having a fullopen receiving end sealed by a body of liquid in the receiver-evaporator when such body is of sulficient volume to fill the receiver-evaporator to a level at or slightly below normal maximum, said other conduit having a portion appreciably higher than any part of the former conduit, the means functioning automatically to return liquid from the receiverevaporator to the generator-absorber due to difference in pressure in the two vessels at the commencement of the cooling period, said other conduit when the liquid seal is broken serving to cause an approximate equalization of pressure in the two vessels and by reason of its higher position having capacity to receive liquid without its overflowing to. the generator-absorber while a flow of liquid is induced by pressure through the first mentioned conduit. I

2. In refrigeration apparatus of the intermittent absorption type, means leading from the generator-absorber to the receiver-evaporator, said means involving two conduits, one that leads from an absorbent liquid collecting portion of the receiver-evaporator, and the other from a point a relatively short distance below the normal maximum level of a body of liquid nearly filling said vessel, the latter conduit having a part sufiiciently higher than the next highest part of the communicative means to prevent liquid from flowing through said latter conduit.

3. In refrigeration apparatus of the intermittent absorption type, a gas return conduit leading from a point a relatively short distance below the normal maximum level of a body of liquid nearly filling the receiverevaporator to a point below the minimum liquid level in the generator-absorber, and a communicative ing two open end branches, one extending to the lowest point of the receiver evaporator, the other branch extending to a point just below the normal maximum level of a body of liquid nearly filling the receiver-evapo-- rator, the highest point of said second branch being sufliciently above any other part of the said conduit to prevent liquid from flowing through said second branch.

5. In refrigeration apparatus of the intermittent absorption type, an unobstructed gas return conduit having its receiving end full open at a point just below the normal maximum liquid level in the receiver-evaporator, said conduit extending therefrom to a point below the minimum liquid level in the generator-absorber, a liquid return conduit extending from the lowest point in the receiverevaporator to a point above the highest liquid level in the generator-absorber, the highest point of said gas return conduit being sufliciently above the highest point of said liquid return conduit to prevent liquid from fiowing through the gas return conduit.

6. In refrigeration apparatus of the intermittent absorption type, a conduit for returning liquid from an absorbent liquid collecting portion of the receiver-evaporator to the generator-absorber due to difi'erences in pressure in the two vessels at the commencement of a cooling period, and an unobstructed gas return conduit leading from the rethe first mentioned conduit to prevent liquid from flowing through the gas return conduit.

7. In refrigeration apparatus of theintermittent absorption type wherein the generator-absorber is situated at a lower level than the receiver-evaporator, a conduit leading from an absorbent liquid collecting portion of the receiver-evaporator upwardly above the maximum liquid level in said vessel and thence to a point below the minimum liquid level in the generator-absorber, and a branch conduit leading from the first mentioned conduit above the maximum liquid level in the receiver-evaporator upwardly a suitable distance and thence downwardly into the receiver-evaporator to a point a relatively short distance below said maximum liquid level. V

8. In refrigeration apparatus of the intermittent absorption type, a gas return conduit leading from a point a relatively short distance below the normal maximum liquid level in the receiver-evaporator to a point below the minimum liquid level in the generatorabsorber, and a liquid return conduit leading from an absorbent liquid collecting portion of the receiver-evaporator and joining the gas return conduit before the latter enters the generator-absorber, the highest part of the gas return conduit being above the normal maximum liquid level in the receiverevaporator an amount equal to or greater than the vertical distance between the highest part of the liquid return conduit and the normal maximum liquid level in the receiverevaporator times the ratio of the specific gravities of the liquids at the absorbent liquid collecting portion of the receiverevaporator and the liquid at the normal maximum level in the receiver-evaporator, respectively.

In testimony whereof, I hereunto afiix my signature.

THEODORE B. FOCKE.

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