US2547887A - Refrigerants and refrigeration processes - Google Patents

Description

Patented Apr. 3, i951 REFRIGERA'NTS AND REFRIGERATION p rnoonssns Winston H. Reed, Radford, Va., and William A. Pennington, Fayetteville, N. .Y., assignors to Carrier Corporation ration of Delaware Syracuse, N. Y., a corpo- No Drawing. 'Application February 24,1949,

1 Serial No. 78,228

{Claims (o1. 5%178) This invention relates to the art. of refrigeration. 7 The general object of the invention is to providean improved system of refrigeration which will enable the production of greater refrigera-v tion, effect with existing equipment than is now obtained by dichlorodifiuoromethane hereinafter called by its trade-name F12.

Another object is to provide a refrigerant for use with a compressor serving a refrigeration system so that when said compressor is driven by .a motor servedby 50 cycle current, refrigeration effect will be produced substantially equivalent to that obtained by F12 in such system with the motor served by 60 cycle current.

g, A further object is to provide a refrigerant which will produce an evaporating temperature approximately to 15 lower than that obtained .irom the use of F12 in the same refrigeration system operated at the same condensing temperature. Another object is to provide a refrigerant which will, increase the capacity of .a given refrigeration system approximately 12% when employing driving elements of given size for the compressor ofthe system over that possible of attainment with the use of F12 in the same system.

The chief feature of the invention is the provision of a refrigerant which will produce a given amount of refrigeration effect in equipment of smaller size or capacity than has heretofore been possible of attainment with available refrigerants suitable for use with safety to occupants of areasserved by such equipment.

Another feature of the invention is the provision or a refrigerant mixture adapted for use inequipment designed specifically for the chief component of the mixture which enables the equipment to provide substantially the same refrigeration capacity even when operated at a substantial decrease in the number of revolu tions per minute.

I The problem of obtaining a refrigerant with capacity greater than that of P12 (dichlorodifluoromethane) but less than that obtained with F22 (monochlorodifluoromethane) has presented an unanswered challenge to the refrigeration industryl g Compressors driven by motors served with 6 cycle current become inadequate to produce' dg sired refrigeration effect when employed in areas, where only 50 cycle current is available. similarly compressors large enough to produce 'satisf' ory results under moderate load conditions are inadequate under peak load conditions; in such cases, too, such a refrigerant would enable a compressor to be used satisfactorily when no existing size designed for F12 would be adequate. While the need for such a refrigerant was obviousyasearch of available compounds failed to disclose any. which would present a solution to the problem. .Such a new refrigerant must not only have a capacity greater than F12 but also have all the other essential characteristics, that is be' non-inflammable, substantialy nontoxic, non-explosive, non-corrosive of ordinary metals encountered in 1 a refrigeration system, stable under; desired ,operating conditions and possessing a suitable melting point.

We have found an azeotropic mixture coin-- posed of dichlorodifluoromethane and methyl. chloride to be particularly advantageous for the purposes described above. This specific azeotropic mixture is adapted for use with equipment designed for the use of dichlorodifiuoromethane when it is necessary to operate said equipment at.

a considerable reduction in speed and provides a material increase in refrigeration capacity at such reduction in speed. Dichlorodifluoromethane possesses a boiling point of -21.7 F". at atmospheric pressure while methyl chloride possesses a boiling point of -11.4 F. at atmospheric pressure. When these ingredients are mixed in an amount comprising approximately 78.5 parts by weight of dichlorodifluoromethane and ap-' proximately 21.5 parts by weight of methyl chloride an azeotropic mixture is formed having a constant boiling point of approximately 32 F. at 50 lbs. per square inch absolute pressure. Theoretically this would indicate a boiling point of approximately -26 F. at atmospheric pressure. The mixture, therefore, possesses a lower boiling point and, from the standpoint of economy, somewhat lower in cost than a refrigerant composed solely of dichlorodifluoromethane.

The use of such azeotropic mixture in refri'gcrating equipment designed to employ dichlorodifiuoromethane increases the capacity of the equipment. For example, assume refrigerating equipment such as a compressor designed for use with dichlorodifluoromethane and for operation with cycle current at 1750 R. P. M. is instead operated with 50 cycle current. Such operation reduces the speed of the compressor to approximately H50 R. P. M. with an accompanying reduction in capacity. Substitution of the azeotropic inixture of our invention in such compressor in place of dichlorodifluoromethane provides a materialincrease in capacity. The refrigeration capacity obtained by means of the substituted refrigerant compares favorably with the capacity of the equipment when the compressor is operated at its standard or normal speed with dichlorodifluoromethane.

Such equipment may be designed for use at a condensing temperature of approximately 104 F. and at an evaporating temperature of 32 F. In operation the azeotropic mixture may be condensed at a condensing temperature of 104=F.

then transferred to the evaporator or heat exchanger to be evaporated at a temperature of approximately 32 F. to provide the required heat transfer. The evaporated mixture is thencompressed and again condensed. The concentration of the refrigerant remains. the'sa'me as it is evaporated or vaporized, with each of the components remaining in the same ratio with respect to the other. Likewise, the components in the of a mixture of dichlorodifluoromethane and methyl chloride having a pressure at a predetermined temperature greater than the pressure of either component at such temperature and containing approximately 78.5 parts by weight of dichlorodifluoromethane and approximately 21.5

parts by weight of methyl chloride.

2. In a refrigeration system, a refrigerant comprising a vapor and a liquid in equilibrium with one another, the composition of said vapor being the same as the composition of said liquid, said refrigerant consisting of an azeotropic mixture of dichlorodifluoromethane and methyl chloride having a boiling point of approximately 32 F. at 50 p. s. i. a. and containing approximately 78.5

4. parts by weight of dichlorodifluoromethane and approximately 21.5 parts by weight of methyl refrigerant remain in the same ratio duringthe compression and condensation stages, Inotherwords, the concentration and boiling point of ap- ."plicants refrigerant remain constant'atiany given pressure encountered during the refrigeration cycle.

When the compressor of such equipment using .this refrigerant was run only five-sixths as fast as against full speed when F12 was used, no substantial difference in capacity resulted. Thus .the new refrigerant where used in a machine with 50 cycle current gives almost the same refrigeration capacity as F12 does in the same .machine with 60 cycle current. In all tests the power required for a unit of refrigeration was practically the same.

For purposes .of nomenclature the new re- 'frigerant will becalledarefri'galoy.

Applicants refrigaloy is chemically stable, causes no appreciable corrosion in metals normally encountered in a refrigeration system and has failed to burn even when the refrigerant was preheated to some 300 F. It provides a concstant temperature throughout for example the entire length of an evaporator coil forming part of the refrigeration system. We claim:

' 1. A refrigerant for use in a compressor-condenser-expander refrigeration system consisting chloride.

3.- A- method of increasing. the capacity of a system for producing refrigeration effect consisting in introducinglinto a refrigeration system a components remaining in the same ratio with respect to each other, and then successively compressing and condensing the refrigerant.

WINSTON H. REED. 1 WILLIAM A. PENNINGTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,191,196 Fleischer Feb. 20, 1940 2,255,587 Hubacker Sept. 9, 1941 2,255,588

Hubacker Sept. 9, 1941