US 2479259 A
Description (OCR text may contain errors)
We have found a mixture of dichlorodiuoroincrease in refrigeration capacity atsuch reduc- Y tioninspeed.
It also permits equipment designed for use with dichlorodiuoromethane as a refrigerant to be operated With the same motor at the same speed to provide lower suction temperatures and permits a larger motor to be used if desired to obtain a substantial increase in capacity at the same suction temperatures.
Dichlorodiuoromethane possesses a .boiling point of 21.6 F. at atmospheric pressure while unsym. diuoroethane possesses a boiling point of 11.5 F. at atmospheric pressure (14.69 pounds per square inch). Dichlorodiuoromethane at a temperature of 32 provides a pressure of about 45 pounds per square inch absolute which may be regarded as normal or 100%. Unsym. diluoroethane at a temperature of 32 possesses a pressure of about 38.5 pounds per square inch absolute. According to Raoults Law, any mixture of such materials should possess a pressure between the two extremes. Contrary to this law, however, the addition of unsym. diluoroethane to dichlorodiuoromethane increases the pressure over a wide range to provide a highly desirable increase in capacity. Such increase in capacity amounts to about 18% depending upon the quantity of unsym. diuoroethane mixed with dichlorodifluoromethane; our
tests indicate that the increase in capacityv 'amounts to approximately 17.8%. tion is directed to any mixture of such mate- Our invenrials providing an increase in capacity over the capacity provided by dichlorodiuoromethane alone under the same conditions of use. Our invention includes any mixture of unsym. diuoroethane and dichlorodifluoromethane capable of providing an increase in capacity up to about 18% in refrigerating apparatus designed for use with dichlorodiuoromethane when the apparatus is operated at a given speed over the capacity possessed by the equipment when dichlorodiuoromethane alone is used at the same speed.
An azeotropic mixture of dichlorodifluoromethane and unsym. difluoroethane provides thel 4 ating equipment designed for dichlorodiuoromethane permits decreased temperatures to be obtained while operating the `compressor with the same motor at the same speed. Likewise, the use of such azeotropic mixture greatly increases the capacity of the equipment. For example, a compressor designed for use with dichlorodifluoromethane and for operation on 60 cycle current at 1750 R. P. M. possesses capacity. Substitution of the azeotropic mixture of our invention in place of dichlorodiuoromethane increases the capacity about 18%. If the compressor designed for use with dichlorodifluoromethane and for operation on 60 cycle current at 1750 R. P. M. is operated on 50 cycle current, the speed of the compressor is reduced to approximately 1450 R. P. M. with an accompanying reduction in capacity of about 17%. The substitution of the azeotropic mixture of our invention in place of dichlorodiuoromethane under such circumstances provides an increase in capacity of about 18% and permits the recovery of the lost capacity caused by the reduction in speed. Such increase in capacity obtained by means of the substituted refrigerant compares favorably with the capacity of the equipment when the compressor is operated at its normal speed with tne refrigerant for which the equipment is designed. Such equipment may be designed for use at a condensing temperature of approximately F. and at an evapoiating temperature of approximately 40 F. In operation the mixture may be condensed at a condensing temperature loi' approximately 105 F., then transferred to the evaporator or heat exchanger and evaporated at a temperature of approximately 40 F. to provide the required heat transfer.
While we have found that the specific azeotropic mixture recited above provides the great- :est increase in capacity under the conditions described it will be understood that any mixture of dichlorodifluoromethane and unsym. diuoroethane which provides greater pressure serves to increase the capacity of the compressor over the .capacity provided by dichlorodinuoroinethane.
It will be appreciated, of course, that the respective amounts of unsym. diuoroethane and -dichlorodiuoromethane in the azeotrope vary in accordance with temperature and pressure; that is, the amount of unsym. diiiuoroethane contained in the azeotrope changes gradually as the temperature for example increases. The amount of unsym. diiiuoroethane contained in the azeotrope vrecited above is based on 60 pounds per square inch absolute pressure and a boiling point of approximately- 40 F.
This invention provides a novel refrigerant for 'use in refrigerating equipment. The refrigerant -mixture so provided may be used in equipment specifically designed for use with the chief component of the mixture and greatly increases the capacity of the equipment when so used. This is particularly desirable when it is necessary to `operate the equipment at lower speeds Which, of course, would reduce the capacity when used with the refrigerant for which it is specifically designed. Our invention provides a refrigerant possessing properties intermediate the properties possessed by dichlorodiuoromethane and monochlorodiuoromethane. The refrigerant so provided may be substituted in a system designed for use with dichlorodifluoromethane as a refrigerant to provide lower temperatures while re- 75 taining-the same motor operating at the same speed for actuating the compressor of the system. If desired, an increase in capacity may be obtained by using a larger motor to operate the compressor. The novel refrigerant so provided eifectively lls the gap in available refrigerante f invention is not limited thereto since it may be otherwise embodied within the scope of the fol'- lowing claims.
We claim: Y
1. The process of producing increased refrigeration effect in a refrigeration cycle designed for using dlchlorodiuoromethane consisting in 20 evaporating an azeotropic mixture of dichlorodiuoromethane and unsymmetrical difluoroethane, compressing and condensing the evapo- 6 rated azeotropic mixture to produce refrigeration eiect substantially eighteen per cent greater than that produced by the use of dichlorodiuoromethane alone in such cycle.
2. The -process of transferring heat in a refrigeration cycle consisting in evaporating an azeotropic mixture of substantially seventy-six parts by Weight of dichlorodiuoromethane and substantially twenty-four parts by weight of unsymmetrical diuoroethane, and then compressing and condensing the azeotropic mixture.
WINSTON HARRISON REED. WILLIAM ALVIN 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 2,255,584 Hubacker Sept. 9, 1941