Патент USA US2104882код для вставки
Jara. il, 1938. T. MIDGLEY, JR.. ET AL ~ 2,104,882 HEAT TRANSFER AND REFRIGERATION ‘ Original Filed NOV. 19, 193] 0 Í â 5 4 / 6 .= CCL3 7= cHcLF 0'0 Y ß e@ 2 , INVENTORS Thoma.: Mid9 /e.y J'.e, Alberi' L. Henne, and ‘ÃÉÍZÍF ` Z BY Pobcfr R New ATTORNEYS 2,104,882 Patented Jan. li, 1938 TESv treoA PATENT OFFICE -`2,104,882 l'HEAT TRANSFER AND REFRIGERATION Thomas Midgley, Jr., Worthington, Albert L. Henne, Columbus, and Robert R. McNary, Day ton, Ohio,'assignors to General Motors Corpo ration, Dayton, Ohio, a corporation _of Dela x original application November-:19, 1931, serial Divided and this application May 1, 1934,' Serial N0. 723,372 ` N0. 576,052. (Cyl. l62---178) s claims. This application relates to the art of trans ferring heat from one point to another and spe cifìcally to the art of refrigeration and is a' divi Because there are several variables, and be cause- of the value of relative proportions, we have placed the compounds of the group just discussed sion of application Serial Number 516,052, pat on plots wherein ented July 31, 1934, No. 1,968,049. A p Heretofore, as far as we are aware, refrigerants and heat transfer agents have been chosen chiefly for their boiling points and stability in the re frigerati'ng or heat transfer cycle irrespective of I V mability and non-toxicity. corresponding to the numbers used in Fig. 2.' Referring to the plots generally, the dashed _It is the object of our invention, on the other hand', to provide a process of refrigeration and, lines indicate chlorine substitution. other desirableproperties, such as non-infiam generically, a process of heat transfer in which 15 these desirable properties, such as 'non-innam mability and non-toxicity, are obtained- in com lines indicate fluorine substitutions and the solid SimilarV plots are obtained with bromine and iodine in place of chlorine except that the plot is elongated in the direction of higher temperatures with bromine, , while with iodine the temperatures are still more Broadly stated, the part of our processwhich elevated. The amount of elongation is readily de termined by applying the boiling points of some of bination with the desired boiling points. ‘ deals with the controllingof the properties of the 20 refrigerating or heat transfer agents consists in these compounds. , _ replacing hydrogen by iluorine or otherhalogen, Referring speciñcally to Fig. y1, this plot con or both, in aliphatic hydrocarbons in which at least one hydrogen has already been replaced by tains all the compounds which» can be derived fluorine. 25 ' Fig. l is a plot applying the rules of substitution Ul to typical groups having one carbon atom, Fig. 2 is a plot applying the rules to groups hav ing two carbon atoms, and . Fig. 3 is a key to Fig. 2, showing the radicals , ’ , ` Broadly stated, the <part of our process which relates to the` transfer of heat or the production of refrigeration comprises changing. the physical Y state of,- for example, by condensing or evaporat ing,_a halo-iiuoro derivative of an aliphatic hy from CHaF by chlorine and/or fluoriñe substitu tions, together with data which assist in the for mation of the plot. On the base line appear the. numerals zero to` four which show halogen Vcon tent, and the vertical line gives the approximate boiling points in degrees centigrade. At each point of intersection is given the chlorine and 30 drocarbon, and dissipating to, or withdrawing iiuorlne content and the complete formula of the from, an object to be heated or cooled, thelatent heat necessary for changing the physical state of the said derivative. By a halo-nuoro derivative corresponding compound is found by making this halogen substitution for hydrogen in the formula of an aliphatic hydrocarbon we mean aderivative at about _25° centigrade to indicate approxi ' containing more than one ñuorlne atom with or ‘without other halogen atoms, or one ñuorine atom with one or more other halogen atoms. Referring now speciñcally to oui- mode of con-4 trolling the properties of the refrigerating or heat 40 .transfer agent, aliphatic monoñuorides form the structural nucleus on which the agents are built. Broadly speaking, if in the structural formula CHSF we increase the ñuorine content (number of atoms) by the substitution of fluorine for hydro gen, the boiling point decreases, stability increases, CH4. We have drawn a horizontal dashed line mately the optimum vapor pressure conditions “ which we desire for operating an air cooled re frigerator. It is obvious that one may deviate more or less from this line to obtain optimum conditions which include someA other factors, so that within the neighborhood of this line we can provide a suitable refrigerant to meet a wide vari >ation in limitations imposed. If under other re frigerating conditions another optimum line is“ found desirable, the same choice may be made'in inñammability decreases, and toxicity decreases. the neighborhood of that line. In fact, the actual operation of the refrigerator and the providing of If we keep the fluorine contentconstant and sub the characteristics of the refrigerant are here stitute another halogen for` hydrogen in the nucleus, the stability decreases, the toxicity in desirable process of refrigeration under a given combined as one problem so as to obtain the most 50 creases, -and the .inñammability decreases. 'The set of conditions. , I In Fig. 2 we have shown the same mode of degree to which these variations take place de pends on what the other halogen (chlorine, controlling the properties of a refrigerant carried to compounds of the same type as in Fig. 1 but bromine, or iodine) is. `As the ratio ofthe halo gen content to the hydrogen content increases the , having two carbon atoms.A The key to the chart A55 iniiammability decreases. is given in Fig. 3. For example, compound 0.1 is 2,10%@82 2 CH3.CH2F, compound 2.9 is CHFaCCl-ZF, com pound 1.5 is CHzFCI-IClz, _and compound 2.2 is CHFz.CHFz. When We choose as our nucleus a compound having'two or more carbon atoms We find that the structural formula gives a choice as to Where the substitutions of the halogens shall be made. For example, the structural formula of C‘2H5F is CHsCHzF, which has a boiling point at about derivative which contains more than one fluorine atom with or without other halogen atoms, or one ñuorine atom with one or more other halogen atoms, and by dissipating to or withdrawing from an object to be heated or cooled, the latent heat necessary for the change in physical state. More specifically, to produce refrigeration, we may evaporate the desired derivative in the vicinity of a body to be cooled, while if a heating effect _32° C. If we_make a fiuorine substitution for is desired, we may condense the derivative in the vicinity of a body to be heated, it being under refrigerating agent whose boiling point is about stood, of course, that the terms “evaporation” and “condensation” include the separation of a gas from, and the absorption of a gas in, an ab 10 hydrogen in the second radical of this structural formula so that it reads GHz-CHFz we have a _26° C. If we make the fluorine substitution for hydrogen onto the other carbon atom so that the 15 formula reads CHzF-_CHzF the boiling point of this refrigerant is about _5° C. Thus the ñrst type of substitution yields a compound boiling substantially lower than the compound obtained by the second type of substitution and the chart 20 shows this to be> general. The substitution of chlorine, bromine or iodine for hydrogen raises the boiling point, but the substitution in a radical which does not already contain a halogen raises the boiling point more than when the substitu25 tion is made in a radical which already contains a halogen. I v The plot may be expanded in like manner with other aliphatic mono-iluorides. As the number of carbon atoms increases the complexity and ex tent of the plot will increase together with the number of halogens present. These halogen derivatives of aliphatic mono-fluorides may be represented b-y the formula 35 sorbent respectively. 15 ^ Our invention will probably ñnd its greatest utility by adjusting both the mode of preparing the refrigerant to obtain desirable characteristics and the mode of using the refrigerant to obtain a process of refrigeration or heat transfer which 20 meets the limitations imposed. We prefer to employ refrigerants boiling above _60° C. Obviously our invention is not limited in its application to any specific form of apparatus for carrying out the mode of operation described and it will not be necessary for a complete under standing of the invention to show a specific em bodiment of apparatus. Nor is the present inven tion limited to the examples set forth, for a par ticular advance of the present invention resides 30 in the fact that a great number of new refriger ants with graduated properties is rendered avail able, and that one is accordingly enabled to se cure the most suitable refrigerant for varied pur poses. W'hat is claimed is as follows: 1. The process of transferring heat which com C represents carbon and n the number of car- - bon atoms in the molecule which is always equal to one or more. 40 ' . 2. The process of transferring heat which com 40 prises condensing and subsequently evaporating CHsCClzF. fulfill the requirements of our invention, . ' F represents fluorine and p the number of prises condensing and subsequently evaporating more. _ _ X represents chlorine, bromine or iodine or combinations thereof and r the total number of such atoms. r may be zero when p is greater than one. 50 CHaCClFz. H represents hydrogen and m the number of atoms thereof, which may equal zero and still atoms thereof which is always equal to one or 45 prises condensing and subsequently evaporating v 3. The process of transferring heat which com a halo-fluoro derivative of ethan -having the general formula CzHaXmF(3-m) where X equals a halogen other than fluorine and is never‘less than one. . 4. The process of transferring heat which com prises condensing and subsequently evaporating Among the chemical groups that these re frigerants fall in are halogen derivatives of all a halo-fluoro derivative of ethan having the general formula C2H3ClmF(3_m) where m is never phatic mono-fluorides, halogen derivatives of less than one, alkylv mono-fiuorides, aliphatic fluoro halides, alkyl iiuoro halides, fluoro derivatives of methyl lfluoride, ?luoro-halo derivatives of methane and fluoro chloro derivatives of methane. Thus by our mode of making fiuorine and/or Aother halogen substitution in a mono-fluoride, We can meet any conditions of Arefrigeration and provide our refrigerant with the desired proper ties, such as non-toxicity and non-infiammabili ty, along with such properties as stability and proper boiling points. Referring more specifically to the part of our 65 process which relates to the actual transfer of heat, We accomplish this transfer of heat by \ changing the physical state of, for example, con densing or evaporating our aliphatic hydrocarbon ‘ 5. The process of transferring heat which com prises condensing and subsequently evaporating ` any halo-nuoro derivative of ethane having the general formula CzHnXmFs-(Mm) , where X equals a halogen other than ñuorine and 11. and m are never less than one. - ‘ 6. The process of producing refrigeration 60 which comprises evaporating in the vicinity of a body to be cooled and subsequently condensing any halo-fluoro derivative of ethane having they - general formula czHnXmFs- (Mm) , where X equals a halogen other than ñuorine and n and m are 65 never less than one. 'THOMAS MIDGLEY, JR. ALBERT L. HENNE. ROBERT R. MCNARY.