US1720160A - Absorption refrigerating machine - Google Patents

Description

July 9, 1929. w EY 1,720,160

ABSORPTION REFRIGERATING MACHINE Filed June 25, 1923 In 2) e1 1 1171231 11 ".1 the absorbing liquid used with it.

Patented July 9, I i

UNITED. srATEs ELIAS WIBT H-FRCEY, OF A ARAU, SWITZERLAND.

" momma REFRIGERATING MACHINE.

Application filed Julie 25, 1923, Serial No.

This invention relates'to'im'provements in refrigerating machines or apparatus of the absorption type.

It is known that refrigerating machines of 5 this class working intermittently by means of a generator-absorber are particularly suitedfor household purposes and for similar se on a small scale, owing to the fact that no gas compressor or pumps are required inv con- 1 nection therewith. q

The great drawback inmachines 0f-this kind as hitherto constructed is that the evaporator gradually becomes filled with a residue consisting of the cooling agent and In the generating operation part of the less volatile absorbing liquid naturally passes over together with the more volatile cooling agent, and this results in theevaporator containing a constantlyincreasing amount of residual liquor. Inconsequence of the increasing proportion of absorbing. liquid therein, the vapour pressure, is reduiied and this liquor I consequently fails to evaporate at the absorp- D tion-pressures at whichthe apparatus works.

Gradually therefore, the evaporator becomes filled'up with residual liquor, and theexchan e of heatbetween the evaporator and the a sorbermay eventually stop entirely.

Attempts have been made to obviate this defect by interposing an auxiliary cooler between the generator and the condenser and condensing mainly the evaporated absorbent therein. If, in spite of this, some of the absorbin liguid passes into the evaporator, it

must e \either by means of suitable piping and valves, an operation which involves a certain amount of attendance and the provision of fittings, or 40 by heating the evaporator externally in order @to raise its temperature, thereby ing the residual liquor to evaporate.

Butmeans ofthis kind are not admissible in small refrigerating machines which are usually attended by servants. On the contrary,it is imperative to construct themso as to operate automatically.

The object of the present invention is to provide an automatic refrigerating machine, that is to say, arefrigerating apparatus in which the aforementioned drawback is removed by causirig'theliquid settling atthe bottom of the evaporator to return automatically to the absorber under the action of gravity. This is preferably effected by means ischarged back to the absorber,

also caus-;

647,733, and i Germany January 5, 1923..

of an overflow device connecting the evaporator with the. absorber in a suitable'manner. In the accompanying drawingione embodiment of my invention isshown'diagrammatically by way of example.-

The refrigerant expelled from the generator-absorber 1 passes into the condenser 2, is there liquefied and then flows from the condenser 2 into the evaporator 3. During the subsequent cooling operation the pipe 5 is closed and the gas formed in the evaporator 3 flows throughthe pipe 4 back into the ab sorber 1. The two pipes or conduits may be combined if desired, but thereis no necessity for doing so. a Any absorbing liquid present in the liquor. passed into the evaporator 3 remains there and, therefore, towards the end of the evaporating process a residue of liquor incapable of further evaporation is-left inthe evaporator 3. This residue could be withdrawn from the evaporator by meansof a valve fitted at the bottom of'the evaporator or b evaporating it by heating the evaporator ext rnally but both methods as already mentioned are notadmissible, the former because of the attendance re,-

quired and the necessity ofhaving a handcontrolled valve member, and the latter because the apparatus is intended for cooling and not for heating purposes. I Q

Now, In invention relies upon the fact that the'lique ed cooling agent has a lower specific gravity than the absorbing liquid and the residual liquor therefore has a correspondingly higher or specific. gravity. The residual liquor c'an'therefore be left in the evaporator for a'time and the apparatus allowedto continue' in operation. As thecoolingagent is' lighter than the residual liquor, it does not mix with it to any'appreciable extent. In order to facilitate the separation of the two liquors, however,-the bottom of the eva orator is formed as a sump 6 where the residual liquor can settle, whilst the cooling agent forms a layer above it. The sump 6 is in open communication with the absorber 1 by means of the by-pass 7.

The overflow level 11 of the by-pass 7 is a little above the normal highest level of the liquor in the evaporator 3, when no absorbing liquid'is present therein. In proportion as the absorbing liquid is distilled over into the evaporator the level of the column'of liquid in the evaporator rises, and as soon as a I certain limit is passed, its weight causes'a corresponding amoi nt of the bottom layer of n'ected up to the bottom of the evaporator, only the liquid contained in the sump 6, that is to say the residual liquor consisting mainly of the absorbing liquid, will be returned to the absorber. The operation is entirely automatic, and no liquid is returned to the absorber, unless some absorbing liquid gathers in the sump 6, and no attention is required to ascertain if any absorbing liquid has collected in theevaporator and has to be discharged therefrom.

The sensitivcncssflof the apparatus may be increased by reducing the cross-sectional area of the evaporator in the region 8 of the overflow level 11, so that only a small amount of excess liquid will suflice to cause the by-pass to act. The larger space 9 above the reduced part8 may with advantage be used for separating the gaseous agent from the liquid dur ing the evaporating operation.

The intensity of discharge may be still furw v ther increased by giving the pipe 7 a special siphon shape, the horizontal top portion and the descending limb being narrower than the rising limb of the siphon whereby, when the liquid in the evaporator rises above a certain level. a sudden evacuation .is effected. The quantity of liquid discharged from the evap orator 3 may be limited either by connecting the descending limb of the siphon pipe with the wider absorption pipe 4 so that the siphoning action ceases when the liquid reaches a. certain level 14, or by providing an auxiliary or relief-pipe connecting the horizontal top portion of the siphon 7 with the evaporator i so that the siphon will be broken at the top when the liquid in the evaporator falls to the level 12.

From the foregoing, it is believed that the advantages and novel features of my invention will be readily understood and therefore r further detailed description is deemed unnecessary. 4

In putting my invention into. practice I find that the preferred embodiment shown herein diagrammatically is the most practical and eflicient arrangement, but realizing that certain conditions will necessarily vary when the invention is carried out in practice, I desire to emphasize the "fact that various changes in the details of construction and arnecessity, in View of the object and scope of my invention, for keeping closely to the particular mode of construction, connection and operation of the parts shown diagrammatically in the drawing by way of example only.

What I'claim is: 1. An absorption refrigerating machine comprising in combination a generator-' absorber for vaporizing a'relatively volatile cooling agent from a relatively low volative absorbing medium, acondenser for condensing said vaporized cooling agent, an evaporator arranged at a higher level. than said generator-absorber, said evaporator comprising upper and lower portions, a constricted -pas sage between said upper and lower portion,

means for transferring condensate from said condenser to said upper portion, a suction pipe connecting saidupper portion with said generator-absorber, and an unobstructed continuously open residue return line from said lower portion to said suction pipe, said return line being capable of allowing the transfer from the bottom of said lower portion of the contents in the lower part of said lower portion, on the level of the contents of the evaporator being in line with the said constricted passage. v

2. An absorption refrigerating machine comprising in combination a generator- ,a sorber for vaporizing a relatively volatile cooling agent from a relatively low volative absorbing medium, a condenser for condensing said vaporized cooling agent, an evaporator, said evaporatorcomprising upper and lower portions, a constricted passage between said upper and lower portion, means for transferring condensate from said condenser to said upper portion, a suctionpipe connecting said upper portion with the generatorabsorber, a sump in said lower portion and an unobstructed siphon connection from said sump to said suction pipe.

In witness whereof I aflix my signature.

ELIAS- WIRTH-FREY.

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