JPH062180A - Treatment of parts of refrigerating machine using hydrofluorocarbon refrigerant - Google Patents

Abstract

PURPOSE:To prevent the deterioration of a refrigerant and the occurrence of sludge by using parts which a metallic base material given coat treatment with ester oil of low viscosity is processed and washed to obtain to assemble a refrigerating machine using a hydrofluorocarbon refrigerant. CONSTITUTION:A metallic base material is previously given coat treatment using an ester oil of low viscosity which is liquid at ordinary temp. Copper, iron, aluminum, etc., are used as the metallic base material and the one having large adsorptive capacity, such as metal powder sintered compact cast products, and forged products is preferable. The ester oil preferably has a viscosity of 1-5cst (40 deg.C) and a low acid value and hydroxyl group value. The metallic base material is given secondary processing, such as cutting to make it parts. Next, after the parts are washed by an alkali washing method, etc., a refrigerating machine using a hydrofluorocarbon refrigerant is assembled by using them. As a result, the survival of metallic foreign matter, ions, cutting oil, washing liquid, etc., is restrained and the deterioration of the refrigerant in a refrigerating cycle and the occurrence of sludge are prevented to perform stable operation for a long period of time.

Description

Detailed Description of the Invention

[0001]

The present invention relates to 1,1,1,2-tetrafluoroethane (CH ₂ FCF ₃ , hereinafter referred to as HFC-13).
4a), 1,1,2,2-tetrafluoroethane (CHF ₂ CHF ₂ , HFC-134), 1,1, -difluoroethane (CH ₃ CHF ₂ , HFC-152a).
The present invention relates to a method for treating refrigerating machine parts using a hydrogen-containing CFC (hereinafter abbreviated as HFC-134a) refrigerant, such as a metal powder sintered product, and a metal base material such as a cast product. By making clean parts by using them and assembling and using the refrigerator, it is possible to suppress deterioration of lubricating oil and hydrogen-containing CFC refrigerant and generation of sludge during the refrigeration cycle, and to stabilize and freeze for a long period of time. The present invention relates to a method for treating a refrigerator part that can operate the machine.

[0002]

2. Description of the Related Art Trichlorofluoromethane (CCl ₃ F, hereinafter CF) is used as a refrigerant for refrigerators, air conditioners, refrigerators, etc.
Abbreviated as C-11), dichlorodifluoromethane (CFC)
-12), monochlorodifluoromethane (HCF)
Freons such as C-22 (hereinafter abbreviated as CFC-12) have been widely used.

In 1974, by Roland (University of California), specified Freon [CFC-11, dichlorodifluoromethane (CFC-12), trichlorotrifluoroethane (CFC-113), dichlorotetrafluoroethane (CFC-114) and chloro. Five types of pentafluoroethane (CFC-115)] have been discovered. Depletion of the ozone layer has a large effect on biological systems, such as a decrease in grain production and an increase in skin cancer. Moreover, it is said that specific CFCs exist in the environment for about 100 years without being decomposed and infrared absorption. Therefore, the contribution to the greenhouse effect is high, and the movement of regulations on specific CFCs is becoming active internationally. 19 in Japan
Regulations on the production and use of specific CFCs were started in July 1989, and the direction to completely abolish the production and use of CFCs was clearly stated. Therefore, in order to maintain the modern society, the production and use of alternatives to specific CFCs have become important.

As described above, there is a strong demand for the use of a substitute for the above-mentioned CFCs containing specific CFCs.
134a and the like have been proposed. On the other hand, CFC
Mineral oil-based lubricating oil is about 6 as the lubricating oil for refrigerant such as -12.
It has been used without problems for 0 years, but if this mineral oil-based lubricating oil is used as a lubricating oil for a refrigerant such as HFC-134a, the compatibility with the refrigerant is poor, so that the mineral oil-based lubricating oil is used in the low temperature part during the refrigeration cycle. Since the mineral oil-based lubricating oil does not circulate efficiently in the refrigeration cycle (bad oil return at low temperature), the amount of oil that works effectively as lubricating oil decreases and the lubricity decreases and the compressor There are problems such as increased wear and accumulation of mineral oil in the evaporator, which causes a reduction in cooling capacity.

As a synthetic oil that replaces the mineral oil type lubricating oil, a lubricating oil for hydrogen-containing CFC refrigerant containing a specific alcohol and an ester of a specific fatty acid as main components (Japanese Patent Laid-Open No. 3-128).
991, JP-A-3-128992, etc.) have been proposed. However, these ester oils have higher water absorption than the above mineral oil-based lubricating oils,
When water is absorbed, there is a problem that it deteriorates in the refrigeration cycle to generate organic acid and cause corrosion.
C-134a, etc. and ester oils, even if the water content is small, are metallic foreign matters, various anions and cations, cutting oils,
If the alkaline cleaning liquid or the like remains, deterioration in the refrigeration cycle is promoted to generate organic acids and the like, which causes corrosion and sludge generation, which makes stable operation of the refrigerator impossible for a long period of time. There is a proposal to add an antioxidant in order to prevent deterioration of ester oil and the like, but the amount added is naturally limited, and HFC-134 in the refrigeration cycle is limited.
It is difficult to prevent the deterioration of a and the like and ester oil.

[0006]

SUMMARY OF THE INVENTION Even when a metal base material such as a metal powder sintered product or a cast product is machined by a conventional method to make a part and a refrigerator is assembled, metal foreign matters, various anions and cations, Since cutting oil, alkaline cleaning liquid, etc. are suppressed from remaining in parts and refrigeration cycles, HFC
-134a, such as hydrogen-containing CFC refrigerants and ester oils, which can suppress deterioration and sludge generation in the refrigeration cycle and can operate the refrigerator stably for a long period of time. Develop processing methods.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the conventional problems, the inventors of the present invention have used a low-viscosity ester oil for a metal base material such as a metal powder sintered product or a cast product in advance. The inventors have found that the above-mentioned problems can be solved by performing a coating treatment by means of a conventional method and then performing a mechanical processing to produce a component, thereby completing the present invention.

The invention according to claim 1 of the present invention is a method for treating parts for a refrigerator using a hydrogen-containing CFC refrigerant, which comprises the following steps. (1) a step of previously coating a metal base material with a low-viscosity ester oil that is liquid at room temperature, (2) a step of processing the metal base material into a component, (3) a step of cleaning the component, (4)
Assembling a refrigerator using the parts.

The invention of claim 2 of the present invention is 1 to 5 cS.
t. The method of treating a refrigerator part according to claim 1, wherein an ester oil having a viscosity of (40 ° C) is used.

The invention according to claim 3 of the present invention is characterized in that the metal substrate is a metal substrate having a large surface adsorption ability such as a metal powder sintered product, a cast product, a forged product. It is a processing method of the described parts for refrigerators.

The ester oil used in the present invention may be any liquid as long as it is liquid at room temperature. Ester oils with a viscosity of (40 ° C.) are preferred. Examples of these ester oils include JP-A-3-128991 and JP-A-3-12.
Examples thereof include synthetic ester oils disclosed in Japanese Patent No. 8992, and synthetic ester oils described in the specification of Japanese Patent Application No. 3-208825, but natural ester oils may also be used, and the present invention is not limited thereto. Absent. Since the acid value, hydroxyl value, and double bond remaining in the ester oil used in the present invention are related to stability, it is preferable that all have low values. However, the total acid value is 0.03 to 0.05 (KO
If it is Hmg / g) or more, an unfavorable phenomenon such as generation of metal soap or the like due to reaction with a metal used in the refrigerator and precipitation thereof occurs, so that the total acid value is 0.
It is preferably 01 (KOHmg / g) or less. Further, when the hydroxyl value exceeds 50, a phenomenon such that the ester oil becomes cloudy at a low temperature occurs, so that the hydroxyl value is preferably less than 50. In the present invention, the ester oil may be appropriately added with additives such as an antioxidant, an antiwear agent and an epoxy compound which have been conventionally used in refrigerating machine oil.

In the present invention, a metal base material is coated with these ester oils at room temperature or under heating at normal pressure or under vacuum by a dipping method, a spraying method, an impregnation method or the like. Is essential. Thus, the surface or the inside of the metal base material is coated with the ester oil, but the amount of the ester oil to be processed, the coating thickness, etc. vary depending on the material, the shape, the manufacturing method, etc. of the metal base material, and therefore it is preferable to appropriately determine. .

The material of the metal base material is copper, iron, aluminum, or an alloy thereof, and in particular, a metal base material having irregularities on the surface or a porous metal powder sintered product, cast product, forged product. The present invention can be preferably used for a metal substrate having a large surface adsorption ability such as a product.

After a metal base material is coated with an ester oil, secondary processing such as cutting is performed by a conventional method, and vane-related parts of a compressor, a four-way valve, a two-way valve, a body such as a valve, a motor case. , Cylinder piston,
Make structural parts for refrigerators such as crankshafts.

Thereafter, these parts are cleaned by a conventional method such as an alkali cleaning method using an aqueous solution of caustic soda.

After that, the refrigerating machine main body is assembled using these parts, and after heating, drying, etc., the refrigerating cycle is started.

[0017]

Function: A metal base material such as a metal powder sintered product or a cast product, which is liquid at room temperature, preferably 1 to 5 cSt. After coating with a low-viscosity ester oil (40 ° C), the parts are machined by a conventional method, and a refrigerator is assembled using the parts to adsorb various adsorbed components on the surface of the metal substrate. it is possible to reduce the various handling steps, the machining process, the foreign metallic substance from such washing steps, Cl ^-, F
_{^{-, NO 2 -, NO 3}} -, PO 4 -2, SO 4 -2 , etc. of various anions and Na ^+, K ^+, cations such as B-type ion, cutting oil, contamination such as alkaline washing solution, today Since miscellaneous matters can be prevented, deterioration of hydrogen-containing CFC refrigerants such as HFC-134a and ester oil in the refrigeration cycle and generation of sludge can be suppressed, and the refrigerator can be operated stably for a long period of time. Will be able to.

[0018]

EXAMPLES Next, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. (Example 1, Comparative Example 1) An iron-based and aluminum-alloy-based metal base material composed of a metal powder sintered product and a cast product was used as an ester oil [Freol α-8, trade name, Kyodo Oil Co., Ltd.
Manufactured] to impregnate it at room temperature to cover it, and then perform secondary processing such as cutting to remove vane-related parts of compressors, four-way valves, two-way valves, valve bodies, motor cases, cylinder pistons, crankshafts, etc. I made structural parts for refrigerators. After that, perform alkali cleaning, assemble the commercial refrigerator body using these parts, heat,
It was dried. Although it was operated continuously for 3 months at + 45 ° C setting, stable operation was possible and no sludge was found. On the other hand, in the case of the comparative example performed in the same manner as the example except that the coating treatment with the ester oil was not performed,
Sludge was generated and the filter was clogged during the refrigeration cycle, so stable operation was not possible. Table 1 shows the results of analysis of the refrigerant (HFC-134a) [ion chromatography, IC-7000, manufactured by Yokogawa Electric Co., Ltd.] after three months of operation.

[0019]

Table 1 Cl ⁻ , F ⁻ , NO ₂ ⁻ , NO ₃ ⁻ , PO ₄ ⁻² , SO ₄ ⁻² Example 1 1.9 0.5 − − − 1.2 Comparative Example 1 5.3 10.9 2.8 1.1 6.0 1.5

[0020]

The present invention provides HFC-134a, HFC-
134, HFC-152a, HFC-32, HFC-1
No. 25, HFC-143a, and other related methods for treating refrigerating machine parts that use a hydrogen-containing CFC refrigerant, in which a metal base material such as a metal powder sintered product or a cast product is previously coated with liquid ester oil at room temperature. After that, by machining it by a conventional method to make clean parts and using it to assemble a refrigerator, it is possible to suppress deterioration of lubricating oil and hydrogen-containing CFC refrigerant and generation of sludge during the refrigeration cycle. It has become possible to operate the refrigerator stably over a long period of time. The significance of being able to solve the conventional problems by the method of the present invention is great, and its industrial utility value is enormous.

Claims (3)

[Claims] 1. A method for treating a refrigerating machine component using a hydrogen-containing CFC refrigerant, which comprises the following steps. (1) a step of previously coating a metal base material with a low-viscosity ester oil that is liquid at room temperature, (2) a step of processing the metal base material into a component, (3) a step of cleaning the component, (4)
Assembling a refrigerator using the parts. 2. 1-5 cSt. The method for treating a refrigerator part according to claim 1, wherein an ester oil having a viscosity of (40 ° C.) is used. 3. The metal base material is a metal powder sintered product, a cast product,
The method for treating a refrigerating machine part according to claim 1, which is a metal base material having a large surface adsorption capacity such as a forged product.