JP3219520B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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.

[0002]

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.

Accordingly, the present inventors use a specific raw material for the polyol ester oil, use it in a specific physical property range, add a special additive, or increase the purity of the fluorohydrocarbon-based refrigerant to a high value. It has been found that the above problems can be solved by maintaining or reducing the equilibrium moisture of 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.

[0008]

The present invention SUMMARY OF THE INVENTION are as described in claim 1, a compressor, a condenser, a decompressor and an evaporator low
Refrigeration equipment with refrigeration cycle at least
hand,

The refrigerant used in the refrigeration cycle contains chlorine.
Fluorinated hydrocarbon refrigerant with a purity of 99.95 wt%
As described above, the refrigerant containing 80 ppm or less of the chlorine-based refrigerant
Wherein the refrigerating machine oil used for the compressor is a polyol,
Raw materials obtained by polymerizing linear or side chain alkyl fatty acids without catalyst
The pour point is -40 ° C or less, and the two-part separation temperature is -20.
° C or less, total acid value is 0.02 mgKOH / g or less, viscosity
Is 8 to 100 cst at 40 ° C and viscosity index is 80 or more.
Refrigeration oil based on riol ester oil
is there.

With this configuration, it is possible to prevent the oil from being hydrolyzed at the initial stage of the operation of the refrigerating apparatus, to reduce the total acid value, to suppress the generation of sludge due to the generation of metal soap, and to reduce the occurrence of sludge at the sliding portion. Lubrication characteristics can be secured.

[0011]

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.

At the bottom of the closed container 1, a polyol is
It is composed of a raw material obtained by polymerizing a linear or side chain alkyl fatty acid without a catalyst, and has a pour point of -50 ° C and a two-liquid separation temperature of -3.
An oil 18 of a polyol ester oil having a viscosity of 32 cst at a temperature of 40 ° C. and a viscosity index of 95 is stored at 0 ° C., a total acid value of 0.01 mg KOH / g or less.

For the purpose of preventing oxidative deterioration during long-term storage, this polyol ester oil is added with 0.3 wt% of a phenolic antioxidant of 2,6-di-tert-butyl lacresol (DBPC) as an additive. And also
For the purpose of preventing hydrolysis, 0.25 wt% of an epoxy-based additive is added.

Incidentally, if necessary, 5 ppm of a copper deactivator of benzotriazole (BTA) and an extreme pressure additive of 1 wt% of tricresyl phosphate (TCP) are added to the polyol ester oil. 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 200 or less in the initial operation state , preferably 150 pp.
m . Residual water content in the refrigeration cycle ───────────────── × 10 ⁶ ppm ... I Filled oil amount + Filled refrigerant amount A water adsorbent having a pore diameter of about 3 mm is used. Further, the amount of residual oxygen in the refrigeration cycle A is adjusted to 0.005 vol% of the cycle internal volume.

In the electric element 2 of the compressor B, the winding 4 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 container 1 and guides the refrigerant to the suction side of the cylinder 7. Reference numeral 20 denotes a suction tube which is attached to the upper wall of the closed container 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 in the rotary compressor constructed as described above, 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.

The polyol ester oil 18 of the present invention has good compatibility with R134a in all temperature ranges used in the refrigeration system A, and can eliminate two-layer separation between refrigerant and oil.

For this reason, the polyol ester oil 18 is always kept at 134 ° C. in the low temperature range of −30 ° C. or lower in the refrigerating cycle A.
Since it exists in a state of being dissolved in a and has a low viscosity as a whole, the oil return to the compressor B is good. Therefore, the oil level of the compressor B does not decrease, and the lubrication of the bearing sliding portions 8, 13, 14 can be ensured, and biting and seizure can be prevented.

Moreover, the polyol ester oil 1 of the present invention
8 is a function of enhancing the lubricity by the ester bond held by the oil itself being molecularly oriented mainly on the surface of the iron-based sliding portion of the shaft 8 of the compressor B and the bearings 13 and 14, and easily soluble in the refrigerant (134a). By the action, the actual viscosity can be reduced, the mechanical loss can be reduced, and the coefficient of performance of the compressor B can be improved.

Further, since the purity of the refrigerant 134a is extremely high, foreign matter in the refrigeration cycle A is not
And the stable performance can be obtained by ensuring the compatibility between the polyol ester oil 18 and the refrigerant.

In particular, according to the structure of the first aspect of the present invention, it is possible to prevent the oil from being hydrolyzed at the initial stage of the operation of the refrigerating apparatus, to reduce the total acid value, and to generate sludge due to the generation of metal soap. And lubrication characteristics at the sliding portion can be secured.

Further, sludge due to oxidative deterioration and polymerization of the polyol ester oil 18 can be prevented, and a refrigeration apparatus excellent in reliability can be provided.

The polyol ester oil 18 is
As compared with glycol oil or the like, the oxidative deterioration stability can be improved, and the performance and reliability of the compressor B can be improved.

This was also confirmed from the result of an experiment by a shield tube test in which the polyol ester oil 18 of the present invention to which DBPC was added was sealed.

That is, according to the polyol ester 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 at the initial stage. Below
Good results were obtained.

In addition, it is adsorbed on the copper surface to be the bearing sliding surfaces 8, 10, 13, and 14, the catalytic action thereof can be suppressed, and the hydrolysis can be suppressed.

Also, a strong chemical adsorption film can be formed on the bearing sliding surfaces 8, 10, 13, and 14, and the sliding portions 8, 1
The lubricating properties of 0, 13, and 14 are further improved, and biting and seizure can be prevented.

In addition, hydrolysis can be suppressed, the total acid value can be reduced, the production of metal soap can be suppressed, and the reliability of the apparatus can be improved.

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.

[0042]

[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 Residual oxygen content in refrigeration cycle A: 0.03 vol% Chlorine remaining quantity in refrigeration cycle A: 400 ppm Production standard B: (criterion of the present invention) Refrigerant purity: 99.95 wt% Equilibrium water content in refrigeration cycle A: 200 ppm Residual oxygen amount in refrigeration 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. However, the polyol ester of the present invention is not limited to other HFC refrigerants. System oil exhibits excellent compatibility can be applied to these refrigerants.

[0044]

As described above, according to the present invention, a specific raw material is used for a polyol ester oil, a specific physical property range is used, a special additive is added, and a fluorinated hydrocarbon-based refrigerant is used. By keeping the purity at a high value or suppressing the equilibrium moisture in the refrigeration cycle, the hydrolysis of polyol ester-based oils due to the effect of moisture is suppressed, reducing the total oxidation and suppressing the production of metal soap. To prevent adverse effects on the refrigeration cycle,
Decomposition, oxidative deterioration and polymerization reaction are suppressed to prevent the generation of metal soap and polymer sludge, and a good refrigeration apparatus 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.

[Explanation of symbols]

 Reference Signs List A Refrigerator B Rotary compressor F Dryer 1 Closed container 3 Rotary compression element 10 Roller 12 Vane 18 Oil

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C10N 30:00 C10N 30:00 Z 30:12 30:12 40:30 40:30 (72) Inventor Yasuki Takahashi Moriguchi, Osaka 2-18-18 Keihan Hondori Sanyo Electric Co., Ltd. (72) Inventor Kiyoshi Akazawa 2-18-18 Keihan Hondori Sanyo Electric Co., Ltd.Moriguchi, Osaka 2-18-18 Sanyo Electric Co., Ltd. (72) Inventor Masato Watanabe 2-18-18 Keihan Hondori, Moriguchi-shi, Osaka (56) References JP-A-4-183788 (JP, A JP-A-3-275799 (JP, A) JP-A-5-32987 (JP, A) JP-A-5-17789 (JP, A) JP-A-4-178496 (JP, A) 240272 (JP, A) Special Table Heisei 3-502472 (JP, A) (58) key The field (Int.Cl. ^7, DB name) C10M 105/00 - 105/46 C10M 131/00 - 131/14 C09K 5/00 - 5/06 F25B 49/02 C10N 30:00 C10N 30:12 C10N 40 : 30

Claims (1)

(57) [Claims] 1. A compressor, a condenser, a decompression device, and an evaporator.
Refrigeration equipment equipped with a refrigeration cycle having at least
The refrigerant used in the refrigeration cycle is a fluorinated hydrocarbon-based refrigerant containing no chlorine and having a purity of 99.95 wt% or more.
And a refrigerant containing 80 ppm or less of chlorine-based refrigerant.
The refrigerator oil used in the compressor is a polyol and a raw material obtained by polymerizing a straight-chain or side-chain alkyl fatty acid without a catalyst, and has a pour point of −40 ° C. or less, a two-liquid separation temperature of −20 ° C. or less, and When the acid value is 0.02 mgKOH / g or less and the viscosity is 4
A refrigerating machine characterized by being a refrigerating machine oil based on a polyol ester oil having a viscosity index of 8 to 100 cst at 0 ° C. and a viscosity index of 80 or more.