Патент USA US2120559код для вставки
2,120,559 Patented June 14, 1938 UNITED STATES PATENT OFFICE ABSORPTION REFRIGERATION Burgess H. Jennings, Bethlehem, Pa., assignor ‘to The Philadelphia, and Reading Coal and Iron Company, Philadelphia, Pa., a corpora tion of Pennsylvania No Drawing. Application April 20, 1937, Serial No. 137,929‘ 9 Claims. (01. 252—5) at customary absorber temperatures of from 65°v rI’his invention relates to absorption refriger F. to about 110° F. ation, and is particularly concerned with solvent material for refrigerants in absorption type re 0 The absorber pressure is essentially equivalent to that of the refrigerant frigerating apparatus. evaporator, which operates at'temperatures that As is known to those acquainted with the art of absorption refrigeration a solvent material is may vary over a wide range but are ‘customarily 5 between 0° F. and 50° F. It will be seen from the foregoing discussion used to absorb a refrigerant vapor in one phase that the solvent must be able to fulfill-its func tions under varying temperatures and pressures. - of operation of the machine, while in ‘another phase the refrigerant is driven off from the sol 10 vent material because of heat supplied to the solvent mixture. The refrigerant driven off is condensed to liquid, and by suitable means may accomplish refrigeration when it subsequently vaporizes. The refrigerant vapor is then again In addition, its freezing point should preferably 10 not be over about 10° F. 10 centipoises at 68° F. It must also be chemi ticularly in regard to the common metals used 15 ' In the two-?uid type of machine, ‘me chanicalimeans is required to circulate the re frigerant against the different pressures of the system, and only the refrigerant and its vapor and the solvent, with very small quantities of the vapor of the latter, are present in the ma chine. In the three-fiuid type of machine an inert gas, which is always gas, is also present and is used to keep the pressure throughout the machine essentially constant. The inert gas is not essentially soluble in the refrigerant or sol in refrigeration machine construction. It must not form permanent chemical compounds with the refrigerants used. Its speci?c heat should be low for the greatest efficiency. It should be capable of absorbing refrigerant at 90° F. ab sorber temperature and at the evaporator pres sure maintained, and should be capable of los ing at 230° F. and at the condenser pressure maintained, enough refrigerant to allow each ' pound of absorbent circulated a reasonable car- 25 rying capacity. Its minimum boiling temper vent of the machine. ature should be about 240° (preferably above The operation of two-fluid and three-?uid ab sorption refrigeration apparatus is well known to 260° F.) at atmospheric pressure. 22 O those skilled in the art, so that no detailed de scription of such apparatus need here be given. It may be briefly noted that such apparatus com prises a generator or still in which the solvent mixture is heated and the refrigerant driven off as a vapor, a condenser in which the refrigerant vapor is condensed to a liquid‘ state, an evapo rator in which the refrigerant liquid is vaporized ‘ I have discovered that tetrahydronaphthalene (also known as tetralin) effectively meets the requirements of a solvent in absorption refrig eration. Particularly I have found that this sub ‘stance is a desirable solvent for the refrigerant methyl chloride under the conditions prevailing in absorption type refrigerating systems. In ad- 5' dition, this substance may be used in absorption refrigerators as a solvent for other volatile, at reduced pressure, and extracts heat from the medium which is to be cooled, and an absorber in chemically stable, halogenated hydrocarbon re frigerants, such‘as ethyl chloride, dichlorodi which the‘ refrigerant vapor containing, heat ?uoromethane (CClzFz), methyl bromide, mono- . fluorodichloromethane (CHClzF) , dichlorotetra withdrawn from the refrigerated medium is again dissolved in the solvent. ' cally stable at temperatures below 270° F., pare ' absorbed by the solvent and the cycle repeats itself. It should have a vis- cosity preferably not substantially higher than _ A refrigerant solvent must meet satisfactorily widely varying special conditions in absorption iiuoroethane (CZCIZFU, mono?uorotrichloro methane (CFCla) ,and. dichlorethylene (C2H2C12) . With respect to the properties of the refriger ant employed, it may be noted that the refrig- 45 erant should be capable of condensation at tem to 270° F. are commonly employed. The char- ' vperatures not greatly in excess of 100° F. The acteristics of the solvent should be such that in critical temperature value should usually not be lower than 130° F. vaporization must be readily I this temperature range the refrigerant inv solu possible at the pressures for which the system is 50 50 tion can, to a great extent, be removed and pass designed at temperatures as low as 0° for off as a gas into the condensing part of the unit. conventional refrigeration, and usually some Condenser and generator pressures are essential 1y equivalent. Furthermore, the solvent in the what below 50° F. for air conditioning work. It may be noted in passing that many refriger absorber of the unit should be capable of absorb 55 ing an appreciable quantity of the refrigerant ants are in the vacuum region during evapora- . In the ?rst place, in the generator or still, temperatures of from 200° ' refrigerating apparatus. I 2 2,120,559 ' tion and in some of them even during con densation, but that many others may operate in both regions or altogether in the positive pres sure region. The atmospheric boiling point of a substance is thus not necessarily an index of its suitability as a refrigerant because of the possibility of operating in the vacuum region. ‘ However, atmospheric boiling points above 120” F. do not usually represent good refrigerants. 10 The chemical tetrahydronaphthalene to which I refer has the empirical formula C1oH12, consist ing structurally of two'carbon rings constituting naphthalene, one of the rings being completely hydrogenated (except for the double bond com 15 mon to the two rings), and the other ring un changed. This structural formula may be illus trated as follows: ' I claim: ~ 1. A refrigerant mixture for absorption re frigerators,‘ said mixture comprising a hydro genated naphthalene as a solvent and a volatile chemically stable refrigerant soluble in said ‘sol vent. " - ~- ~ 2. A refrigerant mixture for absorption re frigeratprs, said mixture comprising a hydro genated naphthalene as a solvent and a volatile. chemically-stable, halogenated .hydrocarbon re frigerant soluble in said solvent. , 3. A refrigerant mixture for absorption re frigerators, said mixture comprising a hydro genated naphthalene having at least two double bonds replaced by hydrogen atoms as a‘solvent 15 and a volatile chemically stable halogenated hydrocarbon refrigerant soluble in said solvent. 4. A refrigerant mixture for absorption re frigerators, said mixture comprising tetrahydro- ' naphthalene as a solvent and a volatile chemi 20 20 cally stable refrigerant soluble in said solvent. 5. A refrigerant mixture for absorption re The chemical is a rather stable liquid, boiling at 25 about 206° C. and freezing at about —25° C. It is practically non-toxic. ' My invention also includes decahydronaphtha lene (known also as decalin) which is suitable and satisfactory as a solvent for-absorption re frigeration. This chemical, the boiling point of‘ which is about 190° C. and the melting point about —10° C., has the empirical formula CmCia, and structurally consists of two carbon rings ' constituting naphthalene both of which are com pletely hydrogenated. 35 illustrated as follows: This formula may‘ be CH: ERs I o-o ' ‘F/min\ 40 3 /C OH frigerators, said mixture comprising decahyd'ro naphthalene as a solvent and a volatile chemi cally‘ stable refrigerant soluble in said solvent. 25 6. A‘ refrigerant mixture for absorption re~ frigerators, said mixture comprising vmethyl chloride as the refrigerant and a hydrogenated naphthalene as'the refrigerant solvent. 7. A-refrigerant mixture for absorption re 30 frigerators, comprising a hydrogenated naphtha lene as a solvent and a volatile, chemically stable, halogenated aliphatic hydrocarbon re frigerant soluble in said solvent. 8. A refrigerant mixture for absorption re frigerators, comprising a hydrogenated naphtha lene as a‘ solvent and a volatile, chemically 'stable, halogenated hydrocarbon'refrigerant hav / on: i It is to be understood that adulteration of the solvent in its pure form, either by virtue of com mercial impurities or because of addition of other solvent material is within the scope of my in vention as de?ned by the ensuing claims. ing not more than two carbon atoms soluble in said solvent. 40 9. A refrigerant mixture for absorption re frigerators, comprising a hydrogenated naphtha lene as a solvent and a volatile, chemically stable, halogenated methane refrigerant solub in said solvent. ' . ' ‘BURGESS H. JENNINGS.