US 2187388 A
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l0 working fluids in mechanical fluorine derivatives of so or phase on top oi the refrigerant.
Jim. 16, 194
UNITED" dTAEd l ldl ldd PATENT OFWC 2,187,3ild
WUEHHNG ram FOR REFEIGERATING APPARATUS Harry M. Williams, Dayton,
llliio, assignor to No Drawing. Application September 6, 1935, Slerial No. 39,453
This application is a continuation-in-part of y two co-pending applications, Serial No. 465,029, filed June 30, 1930, and Serial No. 524,- 409, flied March 21, 1931.
This invention relates to refrigeration and more particularly to working fluids for refrigerating apparatus having" working parts requiring lubrication within a refrigerant circuit.
Heretofore it has been customary to use as refrigerating systems a mixture of a refrigerant such as sulphur dioxide or ammonia with a mineral oil which is immiscible for the most part with these refrig-= erants. Refrigerating apparatus has been delt signed for use with such a worlrine; fluid and dil flculties are often encountered with such re Irigerating systems when such working fluids are not used. When it is desired to use a non-toxic, non-inflammable refrigerant such as one of the the aliphatic hydrocarlions such as the familiar difluorodichloro-meth one and the tetrafluorodichloro-ethane, diflt culty has been encountered because of the fact that mineral oil is completely cible in all proportions with this class oi. refrigerants.
it is an object of my invention to provide non= tonic, non-inflammable war-hing fluids for reirleerating systems having lubricants which are whtolly or partially immiscible with the refrigeran ore specifically it is an object of my invention to provide a working fluid containing one of the derivatives of aliphatic hydrocarbons, for example, difluorodichloro-methane or-tetrafluorodichloro-ethane with a lubricant where is wholly or partially immiscible therewith.
as one example of my invention, I employ dii'luorodichloro-methane and caster oil as a work:- inc huid or charge for a refrigerating system.
iese two fluids have a relatively small mutual rnlscihility orsolubility and when sumcient cas tor oil is provided in proportion to the difiuorodichloro-methane, this worlrine fluid forms two layers or phases oi liquid.
l have found that diiluorodichloro-methane and castor oil have a limited aildnity for each other so that only a small quantity of castor oil will disappear into the body of the refrigerant, the remainder helng tree in this case as a layer There is usually a relatively small mutual miscibility or solubility between the lubricant and the refricerant, and there may be a slight amount oi refrigerant dissolved in the upper lubricant layer on top of the by of the refrigerant. In this upper layer (till. 252-5) or phase the lubricant greatly predominates since such upper layer or phase is essentially an oily body, it is termed herein a free lubricant.
In the use of this working fluid, the content of the castor oil in proportion to the difiuorodi chloro-inethane may be readily controlled so that for any particular type of machine the free lubricent is of such a quality as desired for the best operation of the refrigerating machine. This gives several benefits in operation such as high emciency and in service the relative quantities of lubricant and refrigerant may be more readily determined as in cases where additional changing is necessary.
As another specific example of a working fluid I embodying my invention I provide a fluid courprising, tetrafiuorodichloro-ethane and castor oil. These substances likewise have only a limited amnity for each other so that only a small quantity of castor oil will disappear into the re frigerant, and the remainder ion a layer on top of the refrigerant containing: a slight amount of refrigerant dissolved therein. This upper layer is essentially an oily body, and is termed herein a free lubricant.
Preferably the castor oil used in the before mentioned working fluid is one which has heen dewaxed by cooling the oil to extremely low tem pcratures by refrigeration until the wax solidifies and then separating the liquid castor oil from the wax. If the castor oil used in these working? fluids containing either difluorodichloro-methane and castor oil or tetrafluorodichlormethane and castor oil has not been dew-"axed, i add a solvent for the was such as methyl or ethyl alcohol in sufllcient entities to prevent the. was from solidifyinc or hecominu ezvely viscom at the lowest temperatures encountered in the reirleer sting system in which the were fluid is to be used.
As another specihc example oi" my invention I provide a woo-hue fluid coinnrlsinc diiluoro: chloro-inethane and. clye. "l'his worlrine fluid likewise form two layers, the one layer or phase being essentially a an oily hody, termed herein a free lubricant, while the other layer forms a refrigerant.
As another specific example oi my invention l provide a working fluid comprising tetraduorodichloro-ethane and glycerine which lihewise forms two phases, one of these phase or layers is an oily body, termed herein a tree luhrieant.
Preferably, I use chemically pure ylycerine. However, it the glycerine contours wan, l add a solvent for the wax such as ethyl or thyl al ,r
cohol in suificient quantities to prevent the wax from congealing in the refrigerating system.
As another specific example of my invention- I provide a working fluid comprising difluorodichloro-methane and diethylene glycol.- This working fluid likewise forms two phases, one of which is a lubricant phase.
Another example of my invention is a working fluid comprising tetrafluorodichloro-ethane and diethylene glycol, which likewise forms two phases or layers, one of which is a lubricant phase.
While I have mentioned specifically difluorodichloro-methane and tetrafluorodichloro-ethane as refrigerants which are not miscible with the lubricants mentioned namely in castor oil, glycerine and diethylene glycol, these refrigerants are merely specific examples of the large class of refrigerants which are fluoro derivatives of aliphatic hydrocarbons to which the present invention is applicable. Of this class of refrigerants, I prefer to employ the halofluoro derivatives of the aliphatic hydrocarbons which contain both densed refrigerant to the flooded evaporator and the evaporation of the refrigerant concentrates the lubricant content of the fluid in the evaporator to such an extent that a layer or phase of free lubricant separates from the refrigerant. This free lubricant in such .a system is returned to the compressor along with the refrigerant by the use of some kind of device in the evaporator for withdrawing the free lubricant from this phase.
The direct expansion type of refrigerant apparatus and method, the condensed refrigerant carrying a slight amount of lubricant is expanded into a confined tube of a substantially uniform diameter where the velocity of the evaporated refrigerant sweeps the separated lubricant back into the compressor.
all coming within the scope of the claims which follow.
What is claimed is as follows:
1. A refrigerating fluid comprising a halofluoro derivative of an aliphatic hydrocarbon and castor oil.
2. A refrigerating fluid comprising dichlorodifluoro methane and castor oil.
3. A working fluid for a compression refrigerating system comprising a fluoro derivative of an aliphatic hydrocarbon and castor oil.
4. A refrigerating medium comprising difluorodichloromethane and castor oil free from superfluous wax.
5. A refrigerating medium comprising difluorodichloromethane, castor oil containing a wax, and a solvent for the wax.
' 6. A refrigerating medium comprising difluorodichloromethane, castor oil, and alcohol.
7. A working fluid for a compression refrigerating system comprising a fluoro derivative of an aliphatic hydrocarbon and glycerine.
8. A working fluid for a compression refrigerating system comprising a fluoro derivative of an aliphatic hydrocarbon and diethylene glycol.
9. A refrigerating medium comprising a halofiuoro derivative of an aliphatic hydrocarbon and a liquid substantially immiscible therewith and having lubricating properties, said liquid being selected from a group of lubricants consisting of castor oil and a polyhydric alcohol having a low pour point and a high vaporization temperature.
HARRY M. WILLIAMS.