JP3397806B2 - Method for producing refrigeration cycle using second generation refrigerant - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a refrigeration cycle, and more particularly to a method for manufacturing a refrigeration cycle using a second generation refrigerant. 2. Description of the Related Art In a refrigeration cycle of a type in which a refrigerant is repeatedly compressed / expanded to perform a cooling / heating operation or refrigeration, ammonia has been widely used in the past, and in recent years, chlorofluorocarbon has been widely used as a refrigerant. As is well known, chlorofluorocarbon has extremely excellent use characteristics, such as being nonflammable, explosive, and toxic, and not corroding metals under normal conditions. However, CFCs, which have been widely used because they are extremely stable chemically, enter the stratosphere when released into the atmosphere, stay there for a very long time until they are decomposed by ultraviolet rays, and block ultraviolet rays. Its use has been restricted internationally as it destroys the ozone layer that protects living organisms, including humans on the ground. For this reason, harmless chlorofluorocarbons that can be used in place of conventional chlorofluorocarbons are being developed intensively.
FC-22, -123, -141b, HFC-134a
CFCs have been developed. However, these newly-developed CFCs of the second generation are both CFC-11 and CFC-11, which are conventionally used.
Compared with 12, -502, -131b1, etc., it has poor compatibility with mineral oil or synthetic oil conventionally used as a refrigerating machine oil, and is separated into two liquids, so that the drive part is worn or sludge is easily generated. There is a problem. [0005] For this reason, the development and improvement of refrigerating machine oils compatible with the second-generation Freon are also being actively pursued. For example, the use of newly developed special ester oils such as hindered esters solves this problem. Attempts have been made, but this special ester oil has a water absorption
000 ppm, which is much higher than the conventional water absorption of mineral oil of about 50 ppm. If the system is assembled in the same manner as before, a large amount of water will remain in the system, and this water will During the adiabatic expansion, it freezes and clogs the expansion valve, so that the refrigeration operation is not performed. There is also a problem that water acts on HFC and special ester oil to hydrolyze to generate organic acids, thereby corroding metal parts. [0006] Therefore, the currently developed HCFC-22, -123, -141b, H
Using a second-generation refrigerant such as FC-134a and a special ester oil such as a hindered ester as a refrigerating machine oil, reducing the amount of water remaining in the refrigeration cycle as much as possible, and producing a practical refrigeration cycle. Had to be developed. SUMMARY OF THE INVENTION The present invention is directed to a refrigeration cycle using a second-generation refrigerant and a special ester oil as a refrigerating machine oil. A method of manufacturing, comprising heating a compressor into which refrigerating machine oil has been injected, blowing low-moisture gas having a water content of 20 ppm or less from a charge port provided on a lower side of the compressor, and simultaneously discharging a low-moisture gas from an exhaust port provided on an upper side. Suction and exhaust are performed, and gas replacement and moisture discharge are performed while maintaining the inside in a reduced pressure state.The suction and exhaust is terminated, the blowing of the low moisture gas is continued, and the internal pressure is maintained at a level exceeding atmospheric pressure. An object of the present invention is to solve the above-mentioned problem of the related art by providing a method for manufacturing a refrigeration cycle using a second generation refrigerant, which is characterized by connecting a machine with a pipe. The compressor is sucked and evacuated from the upper exhaust port to be in a decompressed state. Further, since the compressor is heated, moisture and solvent remaining in the compressor easily evaporate. Since a low-moisture gas having a water content of 20 ppm or less (preferably 10 ppm or less) is blown from the lower charging port, an air current is generated from the lower portion to the upper portion. Solvent vapors are easily discharged. After the inside of the compressor is replaced with low-moisture gas, only the suction and exhaust are stopped, and the blowing of the low-moisture gas is continued to connect the pipes while maintaining the internal pressure at a level higher than the atmospheric pressure. Moisture absorption by the refrigerating machine oil is effectively prevented. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a compressor of a refrigeration cycle, which is connected via a rubber hose 2A connected to a charge pipe port 11 provided on the lower side. Then, for example, a nitrogen gas cylinder 3 filled with nitrogen gas having a water content of 20 ppm or less (preferably 10 ppm or less) is connected, and the gauge pressure is 0.2 to 0.5 kgf / c.
The pressure can be reduced to a pressure of m ² g and injection is possible. Also, an exhaust port 12 on the upper side of the compressor 1
A vacuum pump 4 having an evacuation capacity of, for example, about 100 to 300 l / min and about 0.01 to 0.04 torr is connected via a vacuum evacuation rubber hose 2B so that gas existing inside can be sucked and exhausted. Has become. Reference numeral 5 denotes the compressor 1, for example, 70 to
It is a heating means for heating to about 90 ° C., and is capable of adjusting the amount of heat and maintaining a predetermined temperature. Then, a special ester oil as a refrigerating machine oil is sealed in a compressor which has been assembled and washed and dried with an organic solvent (for example, chlorine-based 1.1.1 trichloroethane). Subsequently, the pressure of the nitrogen gas cylinder 3 is adjusted to, for example, a gauge pressure of 0. 0 through the regulator 31 while the vacuum pump 4 is driven to perform suction and exhaust at, for example, 300 l / min. The pressure was reduced to 4 kgf / cm ² g, nitrogen gas was injected from the charge port 11 at a rate of 1 to 15 ml / min, and gas replacement and water discharge were performed for 15 minutes. Then, only the suction and evacuation by the vacuum pump 4 is stopped, the system is moved to another line, and a copper refrigerant pipe (not shown) is connected to the refrigerant suction port 13 and the refrigerant discharge port 14 of the compressor 1 when the refrigeration cycle is assembled. ) Was connected to the refrigerant tube by silver brazing. By using the low-moisture nitrogen gas to prevent the formation of oxide scale during the brazing, the working efficiency is also improved. Further, a refrigeration cycle was manufactured by enclosing Freon R-134a, one of the second generation refrigerants, in the refrigerant. The interior of the compressor 1 during the gas replacement is 40
Since the pressure is reduced to 0 to 500 mmHg and the compressor 1 is heated to approximately 80 ° C. as described above,
The water and solvent remaining inside are easily evaporated and discharged together with the low-moisture nitrogen gas injected for gas replacement. Table 1 shows that a special ester oil as a refrigerating machine oil having an equilibrium water content of 10 ppm A (manufactured by Kyodo Sekiyu, part number α)
-32S-C) and B (manufactured by ICI, part number 106), a refrigeration cycle was manufactured, and after performing a refrigeration operation for approximately three months, the results of analysis of refrigerant vapor are shown. [Table 1] As is evident from Table 1, the refrigeration cycle manufactured by the method of the present invention has an increased pure component of HFC-134a as compared with the case of manufacturing by the conventional method. Further, HFC-23, -125,
C ₃ HF ₅ , C ₃ H ₂ F ₆ , C ₄
H ₂ F ₆ , other F compounds, and toxic CFCs
Although -1123 and the like were detected by the conventional method, none of these compounds were detected at all when produced by the method of the present invention. Therefore, according to the present invention, HFC-134a, -32, -125, -14
A practical refrigeration cycle can be manufactured by using 3a alone or in combination of two or three types and using a special ester oil as a refrigerating machine oil. Since the present invention is not limited to the above embodiment, various modifications can be made without departing from the spirit of the appended claims. For example, the low-moisture gas to be injected into the compressor 1 is for discharging internal water, residual solvent, and the like, and protects the metal from being oxidized when the pipe is connected with silver brazing or copper brazing. As long as it has a function, the water content is 2
0 ppm or less of argon gas, helium gas, and carbon dioxide may be used. As described above, the present invention relates to a method for producing a refrigeration cycle using a second-generation refrigerant and using a special ester oil as a refrigeration oil, wherein the compressor is provided with a refrigeration oil. Is heated, and a low moisture gas having a water content of 20 ppm or less is blown from a charge port provided on a lower side of the compressor, and, at the same time, suction and exhaust is performed from an exhaust port provided on an upper side,
Perform gas replacement and moisture discharge while keeping the inside under reduced pressure,
A method for producing a refrigeration cycle using a second generation refrigerant, wherein the suction / exhaust is terminated, the blowing of the low moisture gas is continued, the internal pressure is maintained at a level exceeding atmospheric pressure, and the compressor is connected to a pipe. Therefore, it is possible to keep the moisture and solvent remaining in the compressor below a certain limit. For this reason, even if the refrigerant is repeatedly compressed / expanded, it does not freeze and clog the expansion valve, and since hydrofluorocarbon is not hydrolyzed to generate an acid, it does not corrode metal parts. In addition, since the production of fatty acid iron salt and its polymer can be suppressed, a refrigeration cycle that functions normally for a long period of time can be manufactured. In particular, there is a remarkable effect in assembling a refrigeration cycle using an oil-filled compressor without an oil purifier or a lubricator in the refrigeration cycle assembly process.

[Brief description of the drawings] FIG. 1 is an apparatus configuration diagram of an embodiment. [Explanation of symbols] 1 compressor 11 Charge port 12 exhaust port 13 Refrigerant inlet 14 Refrigerant outlet 2A, 2B rubber hose 3 Nitrogen gas cylinder 31 Regulator 4 Vacuum pump 5 heating means

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Claims (1)

(57) [Claim 1] A method for producing a refrigeration cycle using a second-generation refrigerant and using a special ester oil as a refrigeration oil, wherein a compressor into which the refrigeration oil is injected is heated. 20 ppm of water from a charge port provided on the lower side of the compressor
Simultaneously with blowing in the following low moisture gas, suction and exhaust are performed through an exhaust port provided on the upper side, gas replacement and moisture discharge are performed while maintaining the inside under reduced pressure, and the suction and exhaust is completed, and the low moisture gas is discharged. A method for producing a refrigeration cycle using a second generation refrigerant, wherein blowing is continued to maintain the internal pressure above atmospheric pressure, and the compressor is connected to a pipe.