JP3469875B2 - Refrigeration equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a refrigeration cycle using a fluorinated hydrocarbon-based refrigerant containing no chlorine such as 1,2-tetrafluoroethane (hereinafter referred to as R134a) and having a refrigeration oil based on a polyol ester oil. 2. Description of the Related Art Compressors for refrigerators, vending machines and showcases have conventionally used a large amount of dichlorodifluoromethane (hereinafter referred to as R12) as a refrigerant. This R12
Is subject to CFC regulations because of the problem of depletion of the ozone layer. Then, R134a is used as a substitute refrigerant for R12.
Chlorofluorocarbon-based refrigerant (HF)
C, FC) are being studied for refrigerators (for example,
See Japanese Patent Application Laid-Open No. 1-271491). [0003] However, the refrigerant R
134a has poor compatibility with the currently used refrigerating machine oils such as mineral oil and alkylbenzene oil, leading to poor lubrication of the compressor due to poor return of oil to the compressor, suction of separated refrigerant at the time of stagnation startup, etc. There was a problem. [0004] Therefore, the present inventors have studied a polyol ester-based oil as a refrigerating machine oil compatible with the refrigerant R134a. However, when this polyol ester-based oil is used in a refrigerant compressor, particularly in a rotary compressor, the sliding member is corroded by a fatty acid generated by being decomposed by heat,
It is known to cause wear. [0005] Then, the present inventors used R134 as a refrigerant.
As a result of repeated studies to combine a and a polyol ester-based oil as a refrigerating machine oil for use in a refrigerant compressor, in addition to the above-mentioned problems, the polyol ester-based oil is hydrolyzed by the influence of moisture, and The price rises, metal soap is formed and becomes sludge, which has an adverse effect on the refrigeration cycle, or is decomposed, oxidized, degraded, and polymerized by the influence of oxygen and chlorine, and metal soap and polymer sludge are generated and frozen. We found that it had a bad effect on the cycle. In particular, the fluorinated hydrocarbon-based refrigerant enclosed in the refrigeration cycle also contains chlorine-based refrigerant mixed therein. If the amount of the chlorinated refrigerant is large, the amount of chlorine increases and the decomposition, oxidative deterioration and polymerization of the polyol ester oil are caused. It has been found that the reaction causes the production of metal soap and the production of polymer sludge, which causes a problem of stagnation in an evaporator or the like of a refrigeration cycle. [0007] In addition, it has been found that the above-mentioned problem occurs when the amount of chlorine remaining in components such as a compressor, a condenser, and various pipes constituting the refrigeration system is large. Further, conventionally, mineral oil has been used for processing and assembling the component parts, and since this mineral oil is difficult to dissolve in a fluorocarbon-based refrigerant, it is considered that a certain amount of the mineral oil remains. It has been found that solidification occurs in an evaporator or the like in a refrigeration cycle and the stagnation occurs, causing a problem that the refrigeration capacity is reduced or the equipment is damaged. Therefore, the present inventors have maintained the purity of the fluorohydrocarbon-based refrigerant at a high value in a refrigeration system using a polyol ester oil and a fluorocarbon-based refrigerant,
It has been found that the above problem can be solved by suppressing the equilibrium moisture and chlorine balance in the refrigeration cycle. The present invention solves the above problems,
Chlorine-free fluorinated hydrocarbon-based refrigerant (for example, R134
An object of the present invention is to solve the above-mentioned problem when a polyol ester oil having compatibility with a) is used as a refrigerating machine oil and to obtain a good refrigerating apparatus. According to the present invention, there is provided a refrigeration cycle using a fluorinated hydrocarbon-based refrigerant containing no chlorine, wherein a refrigerating machine oil comprising a polyol ester oil as a base oil is provided. The fluorinated hydrocarbon-based refrigerant has a purity of 99.95 wt% or more and a chlorine-based refrigerant mixed in at a concentration of 80 ppm or less, and includes components such as a compressor and a condenser constituting the refrigeration apparatus ( Alkyl benzene hard oil (hereinafter, referred to as HAB) was used as the oil used in the processing and assembling process of the component parts , and the amount of the oil used was set to 10% or less of the amount of oil sealed in the refrigeration system. Further, with such a structure, an alkylbenzene hard oil (HAB ) which is easily dissolved in a fluorohydrocarbon-based refrigerant is used for processing and assembling of the component parts, and the amount of the oil used is limited. chlorine content can be significantly reduced, to prevent solidification of the evaporator or the like in the refrigeration cycle can be prevented damage to the reduction or equipment refrigerating capacity in advance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 is a longitudinal sectional view of a rotary compressor. In FIG. 1, A is a refrigeration cycle constituting a refrigeration apparatus, and is configured by connecting a compressor B, a condenser C, a decompression device D, an evaporator E, and a dryer F with piping. And the compressor B
Has the following structure. Reference numeral 1 denotes a closed container, in which an electric element 2 is accommodated on the upper side, and a rotary compression element 3 driven by the electric element is accommodated on the lower side. The electric element 2 includes a stator 5 having a winding 4 insulated with an organic material and a rotor 6 provided inside the stator. The rotary compression element 3 includes a cylinder 7 and a roller 10 that rotates along an inner wall of the cylinder 7 by an eccentric portion 9 of a rotation shaft 8.
A vane 12 is pressed against the peripheral surface of the roller and is pressed by a spring 11 so as to partition the inside of the cylinder 7 into a suction side and a discharge side, and seals an opening of the cylinder 7 while supporting the rotating shaft 8. Upper bearing 13 and lower bearing 14. The upper bearing 13 is provided with a discharge hole 15 communicating with the discharge side of the cylinder 7. A discharge valve 16 for opening and closing the discharge hole 15 and a discharge muffler 17 are attached to the upper bearing 13 so as to cover the discharge valve. The roller 10 and the vane 12 are formed of an iron-based material. The bottom of the closed container 1 is made of a raw material obtained by polymerizing a trivalent or higher polyol such as trimethylolpropane or pentaerythritol and a linear or side chain alkyl fatty acid without a catalyst. Oil 18 of a polyol ester oil having a viscosity of 32 cst at 40 ° C. and a viscosity index of 95 is stored at −50 ° C., a two-liquid separation temperature of −30 ° C., a total acid value of 0.01 mg KOH / g or less, a viscosity of 40 ° C., and a viscosity index of 95. To this polyol ester oil, 0.3% by weight of a phenolic antioxidant of 2,6-ditert-butylparapressol (DBPC) is added as an additive for the purpose of preventing oxidative deterioration during long-term storage. Also, for the purpose of preventing hydrolysis, 0.25 wt% of an epoxy-based additive is added. Incidentally, to this polyol ester oil, 5 ppm of a copper deactivator of benzotriazole (BTA) and an extreme pressure additive of 1 wt% of tricresyl phosphate (TCP) are added as required. You. The refrigeration cycle A is filled with a fluorinated hydrocarbon-based refrigerant containing no chlorine, for example, R134a. R134a has a purity of 99.97 wt%.
Thus, the mixing of the chlorine-based refrigerant is adjusted to 56 ppm. Further, the equilibrium moisture (shown by the following formula I) in the refrigeration cycle A is adjusted to be 150 ppm in an initial operation state. The dryer F used in the refrigerating cycle A uses a moisture adsorbent having a pore diameter of about 3 mm. Furthermore, the amount of residual air in the refrigeration cycle A is adjusted to 0.005 wt% of the cycle internal volume. The amount of residual oxygen in the refrigeration cycle A is
It is adjusted to 0.01 vol% or less of the internal volume of the refrigeration cycle. The oil used for processing or assembling the components such as the compressor B and the condenser C constituting the refrigeration system includes:
Uses alkyl benzene hard oil (hereinafter referred to as HAB) .
The amount of oil used is controlled so as to be 10% or less of the amount of oil sealed in the refrigeration cycle A. The amount of chlorine remaining in the components of the refrigeration system is determined by the amount of oil 18 and 134a sealed in the refrigeration cycle A.
It is controlled to be 20 ppm or less with respect to the total amount of the refrigerant. That is, 13 enclosed in the refrigeration cycle A
4a The total amount of the chlorine-based refrigerant (CFC, HCFC, etc.) mixed in the refrigerant and the amount of chlorine remaining in the components of the refrigeration system is based on the total amount of the oil 18 and the refrigerant enclosed in the refrigeration cycle A. It is controlled to be 100 ppm or less. The winding 4 of the electric element 2 of the compressor B has a two-layer structure in which a layer made of heat-resistant ester (THEIC) or esterimide is provided on the inside and a layer made of amideimide is provided on the outside. And a PET film of low oligomer specification (0.6 wt% or less as trimer) is used as insulating paper H for insulating between the windings 4 and the like. The oil 18 lubricates a sliding surface between the roller 10 and the vane 12 which are sliding members of the rotary compression element 3. The refrigerant which flows into the cylinder 7 of the rotary compression element 3 and is compressed by the cooperation of the roller 10 and the vane 12 is a refrigerant which is compatible with the polyol ester oil 18.
134a. Reference numeral 19 denotes a suction pipe which is attached to the closed vessel 1 and guides the refrigerant to the suction side of the cylinder 7, and 20 is attached to the upper wall of the closed vessel 1 and is compressed by the rotary compression element 3 via the electric element 2. This is a discharge pipe for discharging the refrigerant to the outside of the closed container 1. In the refrigerating machine oil composition used for the rotary compressor having the above-described structure, the refrigerant R134a flowing from the suction pipe 19 to the suction side in the cylinder 7
The compressed air is compressed by the cooperation of the blade and the vane 12, is discharged through the discharge hole 15, opens the discharge valve 16, and is discharged into the discharge muffler 17.
The refrigerant in the discharge muffler is discharged via the electric element 2 to the discharge pipe 2
0 to the outside of the closed container 1. And oil 18
Is supplied to a sliding surface of a sliding member such as the roller 10 and the vane 12 of the rotary compression element 3 to perform lubrication. Further, the refrigerant compressed in the cylinder 7 is prevented from leaking to the low pressure side. According to the present embodiment, the following effects are achieved by the above configuration. Since the purity of the refrigerant 134a is extremely high, there is almost no contamination of the refrigerant A in the refrigerating cycle A, and there is almost no contamination of the CFC. Chlorine decomposes the polyol ester oil 18 to become a fatty acid, and reacts with the metal to react with the metal. The generation of soap can be suppressed, the precipitation of sludge can be reduced, the compatibility between the polyol ester oil 18 and the 134a refrigerant can be ensured, and stable performance can be obtained. In the early stage of the operation of the refrigerating apparatus, the oil 18 can be prevented from being hydrolyzed, the total acid value can be reduced, and the generation of sludge due to the generation of metal soap can be suppressed, so that the sliding portion 8, Lubrication characteristics at 13 and 14 can be secured. This was also confirmed from the results of an experiment by a shield tube test in which the polyol ester-based oil 18 of the present invention to which DBPC was added was sealed. That is, according to the polyol ester type oil 18 of the present invention to which DBPC was added under the condition that the water content was adjusted to 200 ppm by aging at 90 ° C. × 29 days, the total acid value was 0.01 mg KOH in the initial stage. /
g or less, and good results were obtained. Further, it is possible to prevent oxidative deterioration of the polyol ester oil 18 and sludge due to polymerization, and to provide a refrigeration apparatus excellent in reliability. This was also confirmed from the results of an experiment by a shield tube test in which the polyol ester-based oil 18 of the present invention containing DBPC was added. That is, under the condition that the residual oxygen amount in the refrigeration cycle A was adjusted to 0.01 vol% or less by aging at 90 ° C. × 29 days, according to the polyol ester oil 18 of the present invention to which DBPC was added, In the initial stage, the total acid value was 0.01 mgKOH / g or less, and good results were obtained. In particular, according to the structure of claim 1, in processing and assembling of the component parts, an alkylbenzene hard oil (HAB) which is easily soluble in 134a is used, and its use amount is limited. Can be greatly reduced,
By preventing solidification in the evaporator E or the like in the refrigeration cycle A, it is possible to prevent a decrease in refrigeration capacity and damage to the devices B, C, D, E, and F. Further, since the amount of chlorine remaining in the components such as the compressor B, the condenser C, and various pipes constituting the refrigeration system was regulated, the polyol ester oil 18
The formation of metal soap and the formation of polymer sludge due to decomposition, oxidative deterioration, and polymerization reaction of refrigeration can be prevented, and sludge can be prevented from stagnating in the evaporator E or the like of the refrigeration cycle A. Further, 134 enclosed in the refrigeration cycle A
a The total amount of the chlorine-based refrigerant mixed in the refrigerant and the amount of chlorine remaining in the components of the refrigeration system was regulated to 100 ppm or less based on the total amount of the oil 18 and the refrigerant enclosed in the refrigeration cycle A. , The mixing of chlorine in the refrigeration cycle A can be regulated as a whole, and the decomposition of the polyol ester oil 18
It is possible to provide a refrigeration apparatus capable of preventing the generation of metal soap and the generation of polymer sludge by oxidative deterioration and polymerization reaction and exhibiting stable performance. The above operation and effect were also confirmed from the results of the durability test using the actual machine shown in FIG. That is, in the graph of FIG. 2 in which the abscissa indicates the duration of the durability test and the ordinate indicates the amount of contamination (the amount of sludge), the polyol ester of the present invention to which additives (DBPC, epoxy, etc.) are added is shown. Using sample 18 of oil 18,
The sample IV showed the best result according to the standard B (restricting the purity of the refrigerant and the amount of water, chlorine and oxygen in the refrigeration cycle A) in which the production standard of the apparatus was restricted as in the present invention. In FIG. 2, the contents of the samples I to IV are as follows. [Table 1] However, Additive X: DBPC + BTA Additive Y: DBPC + BTA + TCP Additive Z: DBPC + BTA + TCP + Epoxy Production Standard A: (Conventional Standard) Refrigerant Purity: 99.90 wt% Equilibrium Water Content in Refrigeration Cycle A: 600 ppm Refrigeration Cycle Residual oxygen content in A: 0.03 vol% Chlorine remaining in refrigeration cycle A: 400 ppm Production standard B: (criterion of the present invention) Purity of refrigerant: 99.95 wt% Equilibrium water content in refrigeration cycle A: 200 ppm Refrigeration Residual oxygen amount in cycle A: 0.01 vol% Chlorine remaining amount in refrigeration cycle A: 100 ppm In the present embodiment, R134a was described as an example of a fluorinated hydrocarbon-based refrigerant containing no chlorine, but is limited to this. The polyol ester oil of the present invention is not used for other HFC refrigerants. It exhibits excellent compatibility and can be applied to these refrigerants. As described above, according to the present invention, the purity of the fluorinated hydrocarbon-based refrigerant is maintained at a high value, the equilibrium moisture in the refrigeration cycle is suppressed, and the amount of residual oxygen in the refrigeration cycle is reduced. Alkaline benzene hard oil (hereinafter referred to as "HAB") is used as oil used in processing or assembling processes of component parts.
Or use, by limiting the amount of chlorine remaining in the mixing amount and components of the chlorine-based refrigerants, the polyol ester-based oil, to reduce the total acid number to inhibit hydrolysis by the influence of moisture, metal soaps A good refrigeration system, which suppresses the generation of metal soap and polymer sludge by suppressing the generation of water and preventing the adverse effect on the refrigeration cycle, and the decomposition, oxidative deterioration, and polymerization reaction due to the influence of oxygen and chlorine. Can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a rotary compressor showing one embodiment of the present invention. FIG. 2 is a graph showing a result of an endurance test of an actual refrigeration apparatus. [Description of Signs] A Refrigerator B Rotary compressor F Dryer 1 Airtight container 3 Rotary compression element 10 Roller 12 Vane 18 Oil

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuki Takahashi 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Kiyoshi Tanaka 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Yo Electric Co., Ltd. (72) Inventor Kiyoshi Akazawa 2--18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Seiki 2--18-18 Keihanhondori, Moriguchi-shi, Osaka (72) Inventor Masato Watanabe 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (56) References JP-A-4-321793 (JP, A) JP-A-4- 316525 (JP, A) JP-A-4-94472 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 1/00 395 C10M 105/06

Claims (1)

(1) A refrigerating cycle using a fluorinated hydrocarbon-based refrigerant containing no chlorine, comprising a refrigerating machine oil having a refrigerating machine oil based on a polyol ester oil, comprising: The hydrocarbon-based refrigerant has a purity of 99.95 wt% or more and a chlorine-based refrigerant is mixed at 80 ppm or less, and is used for processing of components (hereinafter, referred to as components) such as a compressor and a condenser constituting a refrigeration system. Alkyl benzene hard oil (hereinafter referred to as HAB) is used for the oil used in the assembly process.
And the amount of oil used is 10% of the amount of oil sealed in the refrigerator.
% Or less.