JP2962677B2 - 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 compressor applied to a refrigeration cycle in which a refrigerant is compressed and liquefied, such as a refrigerator or a refrigeration system, and the liquefied refrigerant is expanded. A chlorofluorocarbon-based refrigerant having a critical temperature of 40 ° C. or higher and containing no chlorine, such as chlorofluorocarbon 134a
The present invention relates to a compressor having a refrigerating machine oil composition conforming to the above.

[0002]

2. Description of the Related Art In recent years, the use of chlorofluorocarbons (chlorofluorocarbons, abbreviated as CFCs) has been subject to restrictions worldwide due to environmental pollution, in particular, ozone depletion and global warming.

[0003] Freon subject to regulation is Freon 11, Freon 12, Freon 113, Freon 114, Freon 115 and the like, all of which contain chlorine. Fluorocarbons 12 that have been used exclusively as refrigerants in equipment refrigeration systems are also subject to regulations.

Therefore, an alternative refrigerant is required. Recently, hydrogen fluoride carbon (HFC), which has low reactivity with ozone and has a short decomposition period in the atmosphere, has attracted attention as an alternative refrigerant. Is a typical refrigerant. That is, Freon 134a has an ozone depletion potential (ODP)
Is CFC12 (dichlorodifluoromethane CCl
₂ F ₂ ) is 0 when it is 1, and the global warming potential (GWP) is 0.3 or less when Freon 12 is 1. It is nonflammable and its thermophysical properties such as temperature-pressure characteristics are close to those of Freon 12. It is said that there is an advantage that it can be put to practical use without largely changing the structure of a refrigeration apparatus or a refrigerant compressor, such as a refrigerator, a dehumidifier, and an air conditioner (air conditioner), which have conventionally used Freon 12. It has been.

However, Freon 134a (1.1.1-
Tetrafluoroethane (CH ₂ FCF ₂ ) has a very unique property due to its unique chemical structure, and it is difficult to use a refrigerating machine oil such as a mineral oil or an alkylbenzene oil which has been used in a conventional refrigeration system of CFC-12. Poor compatibility, making practical use impossible. In addition, the compatibility of lubrication, friction and abrasion resistance, and the effect on electrical insulation of the sliding parts of the compression machine is a problem, and the development of a new material system for the compressor and refrigeration equipment is eagerly awaited. Have been.

Therefore, before referring to the compatibility problem between the refrigerant and the refrigerating machine oil, a conventional refrigerant compressor and refrigerating apparatus using a CFC-based refrigerant will be described with reference to FIGS.

FIG. 7 is a vertical sectional view of a main part of a conventional hermetic rotary compressor, FIG. 8 is a cross-sectional view for explaining the displacement of the compressor section, and FIG. 9 is a general refrigeration cycle. FIG.

In FIG. 7, reference numeral 1 designates a case relating to a closed container which also serves as an oil reservoir.

The electric motor 22 comprises a stator 19 and a rotor 20, and a rotary shaft 4A made of cast iron is fitted to the rotor 20. The rotating shaft 4A has the eccentric portion 3, and has a hollow shaft hole 17 at one end.

The winding portion 19a of the stator 19 has a core wire covered with an esterimide film, an electrically insulating film of polyethylene terephthalate is mounted between the core portion and the winding portion of the stator, and a rotating shaft is provided. The surface of 4A is finished by grinding.

The compressor section 23 includes a cylinder 2 made of an iron-based sintered body, a cast iron roller 7 fitted into the eccentric section 3 of the rotary shaft 4A and eccentrically rotating along the inside of the cylinder 2, and a tip end of the roller 7. A high-speed steel vane 10 that reciprocates in the groove 8 of the cylinder 2 while being in contact with the other end thereof while being pressed by the spring 9. The main bearing 5 and the sub-bearing 6 made of cast iron or an iron-based sintered body are used as main mechanism elements.

The auxiliary bearing 6 is provided with a discharge valve 27, a discharge cover 25 is attached so as to form a silencer 28, and the main bearing 5, cylinder 2 and auxiliary bearing 6 are connected by bolts 21. .

The back surface 11 of the vane 10 and the cylinder 2
Of the pump chamber 1 surrounded by the groove 8 and the main bearing 5 and the sub-bearing 6
2 are configured.

The main bearing 5 has a suction piece 14 into which a naphthene-based or alkylbenzene-based refrigerating machine oil 13A in which refrigerant Freon gas stored in the bottom of the case 1 is dissolved can be sucked into a pump chamber 12, and the sub-bearing 6 has a pumping piece. Room 12
There is a discharge port 16 through which the refrigerating machine oil 13A can be discharged to the oil feed pipe 15. The oil supply pipe 15 has a shaft hole 17 of the rotary shaft 4A.
Refrigerator oil 13 </ b> A is supplied to the shaft portion 17, and further, the oil can be supplied to the sliding portion at a key point through the branch hole 18.

The operation of the rotary compressor constructed as described above will be described with reference to FIGS. When the compressor is operated and the cast-iron rotating shaft 4A rotates, the tempered cast-iron roller 7 rotates with it, and the high-speed steel vane 10 is pressed by the spring 9, and the tip of the high-speed steel vane 10 abuts against the roller 7 while abutting on the roller 7. Alternatively, the refrigerant reciprocates in the groove 8 of the iron-based sintered body cylinder 2, compresses the refrigerant (Freon 12) flowing from the refrigerant suction port (not shown), and discharges the refrigerant through the refrigerant discharge port 24 to the discharge pipe 29. From the compressor. The winding portion 19a of the stator 19 and the electric insulating film (not shown) are immersed in refrigeration oil in which Freon is dissolved or exposed to a spraying environment by mist.

In the conventional combination of the refrigerating machine oil composed of mineral oil or alkylbenzene and Freon 12, the Freon 12 is completely compatible with the refrigerating machine oil in all usage ranges. There was no need to worry about the two-layer separation phenomenon or the various problems related to the compatibility of refrigeration oil with so-called chlorofluorocarbon 134a in which the refrigeration oil stays in the heat exchanger. However, in the case of a fluorinated hydrocarbon-based refrigerant containing no chlorine having a unique property, for example, Freon 134a, there is no practical refrigerating machine oil that easily dissolves the refrigerant, so that the compatibility between the refrigerant and the refrigerating machine oil is not sufficient. Is the biggest practical issue.

In general, in order to increase the performance of a compressor, that is, the coefficient of performance (COP) indicating the energy efficiency, it was necessary to minimize the mechanical loss of the compressor and to maximize the volumetric efficiency.

Most of the mechanical loss of the refrigerant compressor is caused by friction loss in a journal bearing or a thrust bearing in a mechanical part, stirring power of oil, and the like. Generally, it is based on the theory of fluid lubrication of a journal bearing. It has been said that the best solution is to minimize the coefficient of friction (μ) in the equation shown below.

[0019]

(Equation 1)

Here, N: number of rotations P: surface pressure η: viscosity D: shaft diameter C: diameter clearance That is, in a refrigerant compressor operated under fluid lubrication conditions, in addition to the structural factors of dimensions and shape, the operation is This shows that the actual viscosity of the refrigerating machine oil in a dissolved state of Freon, which is a factor controlled by the environment, is greatly related to the mechanical loss of the compressor.

On the other hand, the condition for maintaining the highest volumetric efficiency is to completely seal the components that perform the compression operation in the machine room for compressing the refrigerant gas so that the refrigerant gas does not leak from the high pressure side to the low pressure side. That is. Also in this case, it is necessary to pay attention to the fact that the actual viscosity of the refrigerating machine oil in which the refrigerant is dissolved is making an important movement.

As described above, in the refrigerant compressor conventionally used for Freon 12 and the refrigeration system using the same, the actual viscosity of the refrigeration oil at the time of the melting of the refrigerant at the rated operation point under the normal operation condition is adjusted to the optimum condition. Means that it is important for the performance of the compressor.

On the other hand, refrigeration systems such as refrigerators, dehumidifiers, and air conditioners, although rare, are often operated in a high-temperature environment far exceeding normal operating conditions. As it becomes thinner, it enters into a so-called boundary lubrication area with metal contact between bearing sliding parts, the friction coefficient increases temporarily, and heat is generated,
Biting and seizure sticking phenomena occur between the bearing and the rotating shaft, which causes the reliability of the refrigerant compressor to be impaired. Therefore, it is necessary to take measures to prevent a fatal problem from occurring even under boundary lubrication conditions. In a conventional refrigerant compressor using Freon 12, chlorine in Freon 12 has effectively acted as an extreme pressure agent. In other words, when biting or seizure adhesion occurs between the bearing and the rotating shaft, the refrigerant Freon 12 dissolved in the refrigerating machine oil as the bearing lubricating oil is decomposed by the frictional heat,
The decomposition product chlorine reacts with the iron on the bearing surface to form iron chloride, which acts as a lubricant.

As described above, in a refrigerating apparatus using a high-pressure container type rotary compressor, for example, a refrigerator,
The operating conditions at an ambient temperature of 30 ° C. are as follows: the discharge pressure of the compressor is about 10 kg / cm ² abs, the oil temperature is about 100 ° C., and the actual viscosity of the oil is 1 to 4.
Alkylbenzene or mineral oil refrigeration oil that becomes cSt (56 cSt at 40 ° C., 6 cS at 100 ° C.)
t) is good in terms of the coefficient of performance indicating the energy efficiency and the reliability of the product, and most products have been used in this range.

On the other hand, a refrigerating apparatus using a low-pressure vessel type reciprocating compressor (the description of the structure and operation is omitted)
For example, in a refrigerator, operating conditions at an ambient temperature of 30 ° C. are such that a compressor suction pressure is about 1.6 kg / cm ² abs, an oil temperature is 85
° C, mineral oil based refrigerating machine oil that has an actual oil viscosity of 2 to 6 cSt (at 40 ° C, 8 to 15 cSt, at 100 ° C,
(1.8-4.2 cSt) have been used as refrigerant compressors and refrigeration systems.

Next, a basic refrigeration cycle in which a refrigerant compressor for sucking, compressing, and discharging a CFC-based refrigerant will be described with reference to FIG.

As shown in FIG. 9, the compressor 40 has a low temperature,
The low-pressure refrigerant gas is compressed, and the high-temperature, high-pressure refrigerant gas is discharged and sent to the condenser 41. The refrigerant gas sent to the evaporator 41 becomes a high-temperature, high-pressure refrigerant liquid while releasing the heat into the air, and is sent to an expansion mechanism (for example, an expansion valve or a capillary tube) 42. The high-temperature, high-pressure refrigerant liquid passing through the expansion mechanism is converted into low-temperature, low-pressure wet steam by the throttle effect and sent to the evaporator 43. The refrigerant entering the evaporator 43 absorbs heat from the surroundings and evaporates, and the low-temperature and low-pressure refrigerant gas exiting the evaporator 43 is sucked into the compressor 40, and the same cycle is repeated thereafter.

Conventionally, Freon 12 has been used as this refrigerant. However, since the use of Freon 12 has been restricted as described above, Freon 13 has been
When 4a is to be used, conventional mineral oil-based or alkylbenzene-based refrigerating machine oil for CFC 12 has CFC 13
The compatibility with 4a was remarkably poor, causing many practical problems. Therefore, the development of refrigerating machine oil having excellent compatibility with Freon 134a has been actively conducted.
Various refrigeration oils have been proposed.

As typical examples, compounds having an ether bond as exemplified below are known.

For example, in Japanese Patent Application Laid-Open No. 1-259093, propylene glycol monoether can be represented by the general formula (10) as “refrigeration oil for CFC compressor”.

[0031]

Embedded image

(Where R in the formula is a group having 1 to 8 carbon atoms and n is an integer of 4 to 19). The terminal of the glycol is etherified and can be represented by the general formula (11) of a jetel type compound.

[0033]

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(Where R ₁ and R ₂ in the formula _each have 1 to 8 carbon atoms)
Alkyl groups, n is an integer, average molecular weight 300 to 60
0) can be further represented by the general formula (12) of a monoether type compound of propylene glycol and an ethylene glycol copolymer in JP-A 1-25995.

[0035]

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(Where R is an alkyl group having 1 to 14 carbon atoms, m and n are integers, and the ratio of m: n is 6: 4 to 1:
9 average molecular weight of 300 to 2000).

The difference between these polyalkylene glycols and conventional mineral oils or alkylbenzene oils is that by introducing an ether bond into the molecule, the affinity for Freon 134a is enhanced, the compatibility is greatly improved, and compression is achieved. Prevents lubrication of the refrigerant due to the two-layer separation phenomenon (separation of refrigerant and refrigerating machine oil without melting) at the sliding part of the machine, and oil return to the compressor caused by the stagnation phenomenon due to oil adhesion to the inner wall of the heat exchanger Improvements have been made to solve various problems relating to the reliability of the compressor and the refrigeration device, such as seizure and biting of the sliding portion of the compressor.

However, those containing a large number of ether bonds (C—O—C) in the molecule as described above have (1) a large saturated moisture absorption rate (easy to absorb moisture) and (2) a low volume resistivity ( 3) Poor oxidative stability, easy to increase total acid value. However, such a method is unsuitable for a refrigerant compressor and a refrigeration apparatus that use a hermetic motor as an electric motor.

That is, although the compatibility with the refrigerant is improved, there is a problem that the insulating material of the motor is superior and the electric insulation characteristics are deteriorated. In any of the above compounds, the terminal group of the molecule having an ether bond is end-capped with hydrogen, and this hydrogen further increases the hygroscopicity. Therefore, a proposal has been made to esterify this hydrogen to obtain a refrigerating machine oil represented by the following formula (see Japanese Patent Application Laid-Open No. 2-132178).

[0040]

Embedded image

(Where R is a hydrocarbon group, R ¹ is an alkylene group, R ² is an alkyl group, and n is an integer giving a viscosity of the compound of 10 to 300 (40 ° C.)). The improvement of the compatibility with the refrigerant is caused by a large number of ether bonds existing in the molecule, similarly to the above, and thus has the same problem.

The compound having an ether bond as described above tends to take in water due to the above problem (1), and the water itself makes the compound itself hydrolyzed and becomes unstable.

In addition, moisture freezes and clogs the capillaries of the refrigeration cycle, causing a pressure imbalance. In addition, from (2), the volume resistivity is reduced, and the voltage insulation is reduced. From (3), when the total acid value increases, the compound is hydrolyzed and becomes unstable.

[0044]

As described above, Freon 134a, which is an alternative refrigerant to the conventional Freon 12, has a unique molecular structure. And has a fatal problem that it lacks compatibility with refrigerating machine oil, which is the basis of refrigerant compressors and refrigerating devices.

Attempts have also been made to improve compatibility, but with this, new problems such as lowering of electrical insulation, problems of moisture, and problems of instability such as hydrolysis and decomposition of compounds by acids are caused. Have been. Hereinafter, each problem will be described in more detail.

If a refrigerating machine oil having poor compatibility is used forcibly, the refrigerant compressor and the refrigerating apparatus cannot be put to practical use in terms of performance and reliability as described below.

In general, when the solubility of the refrigerating machine oil in the refrigerant is low, the oil discharged from the compressor separates in the heat exchanger and the oil component remains on the wall surface, and the amount of oil returning to the compressor decreases. As a result, the oil level of the compressor decreases, causing a so-called oil rising phenomenon, and the oil supply level decreases.

In a refrigeration system in which a large amount of refrigerant is sealed, when the temperature of the compressor is exposed to a low temperature, the liquid refrigerant is unevenly distributed in the bottom of the compressor. Is supplied to the sliding surface of the rotating shaft, making it difficult to secure a lubricating oil film and causing damage to the compressor.

On the other hand, in the refrigerating apparatus, the separated refrigerating machine oil adheres to the inner wall of the low-temperature evaporator and forms a heat insulating layer, thereby significantly impairing the heat transfer performance. When the action of closing the expansion mechanism (capillary tube) or pipe pipe works, the amount of circulating refrigerant is drastically reduced, and the cooling power is reduced. As a compressor, the pressure of the suction gas decreases and the pressure of the discharge gas increases, leading to thermal degradation of the refrigerating machine oil and damage to the mechanical bearings, significantly impairing the long-term reliability of the refrigerant compressor and refrigerating device. Will be.

Therefore, an object of the present invention is to solve these conventional problems, and a first object of the present invention is to provide a highly compatible refrigeration system compatible with a chlorofluorocarbon-based refrigerant represented by chlorofluorocarbon 134a. It is an object of the present invention to provide a compressor that uses machine oil as a lubricating oil, and more specifically, to improve (1) moisture absorption, (2) system resistivity, and (3) oxidative deterioration. At the same time, under all operating conditions of the compressor in the refrigeration cycle, based on a search for a new refrigerating machine oil composition compatible with Freon 134a, at least the critical melting temperature for medium temperature refrigeration equipment such as dehumidifiers To develop refrigerating machine oil that satisfies the first goal of 0 ° C. or less and refrigeration machine oil that satisfies the second goal of critical melting temperature of −30 ° C. or less for low-temperature refrigeration equipment such as refrigerators. Ri, different refrigerant compressors of the intended use in each of the refrigeration cycle, performance, efficiency,
The purpose is to be able to exhibit excellent characteristics in reliability.

Next, the refrigeration system equipped with the refrigerant compressor increases the coefficient of performance (COP) indicating the energy efficiency, which is the ratio between the refrigeration capacity of the refrigerant compressor and the input, under normal operating conditions in which the compressor is generally operated. This will help prevent global warming (GWP) from a long-term perspective.

In order to reduce the input of the compressor as a means for improving the performance of the compressor, it is necessary to reduce the coefficient of friction based on the theory of fluid lubrication of the coaxial bearing. To this end, the solubility of Freon 134a and the refrigerating machine oil of the present invention is measured, and the optimum value of the actual viscosity of the oil used in the compressor is set. The goal is to derive the best coefficient.

Therefore, a second object is to provide a high-performance refrigerating machine oil based on the bearing theory by defining the optimum viscosity range of the refrigerating machine oil for the rotary type compressor of the high pressure vessel type and the reciprocating type compressor of the low pressure vessel type. And high reliability.

However, in the refrigeration cycle, the compressor may be actually operated, although rarely, in a high-temperature environment exceeding the design expectation or in an extremely severe operation such as an overload operation. It is necessary to ensure sufficient reliability.

When the compressor using the Freon 134a is used in a so-called boundary lubrication region involving metal contact beyond the fluid lubrication region of the coaxial bearing, biting and seizure of the sliding portion of the compressor bearing may occur. , Tend to be larger than in the case of the conventional CFC 12. In the case of Freon 12, when the sliding part of the bearing makes metal contact, Freon 12 dissolved in the oil is decomposed to form a chemical film of iron chloride on the iron-based sliding friction surface. It acted as an extreme pressure action, suppressing adhesion and seizure phenomena.

However, in a compressor using Freon 134a, since it is a refrigerant containing no chlorine, it is impossible to supply chlorine. Therefore, it is difficult to expect an extreme pressure effect as in Freon 12. is there.

Therefore, the third object is to use Freon 134
Even if the sliding bearing of the compressor runs out of oil using a chlorine-free Freon-based refrigerant represented by a, ultra-severe operation can be performed by using a refrigerating machine oil to which an extreme pressure agent is added. It is an object of the present invention to provide a compressor that can prevent biting and seizure of a sliding portion and can secure sufficient reliability even in a case where the sliding is performed.

A fourth object of the present invention is to provide a compressor using a chlorofluorocarbon-based refrigerant, such as chlorofluorocarbon 134a, and a refrigerating machine oil composition. Another object of the present invention is to provide a compressor provided with an electrical insulation system capable of withstanding long-term reliability.

[0059]

The first object of the present invention is as follows: (1). A compressor that is used in a refrigeration cycle, stores refrigerating machine oil serving as lubricating oil in a closed container, and compresses at least a refrigerant gas, wherein the refrigerating machine oil has a critical temperature of 40 ° C. or higher and a viscosity of 40 ° C. 2 to 70 cSt at 100 ° C. and 1 to 9 cSt at 100 ° C., and an ester bond (—O
-CO-) by a compressor composed of a refrigerating machine oil based on an ester oil of a fatty acid having at least two fatty acids,
Achieved.

(2). As described above, an ester of a fatty acid having two or more ester bonds in the molecule is indispensable as the ester oil, and one having one ester bond has poor compatibility with a refrigerant and cannot be used. Fatty acid ester oils
It is obtained by an ester reaction between alcohols and fatty acids, and as the alcohols, polyhydric alcohols are desirable.
The fatty acid preferably has 6 to 8 carbon atoms and may be monobasic or polybasic. In addition, ester oils include hindered ester oils and complex ester oils,
Ester oils having a branched structure tend to be more desirable than a linear structure in terms of compatibility with the refrigerant. Examples of practical fatty acid ester oils are shown below by general formulas (1) to (5).

The general formulas (1) to (4) are examples of a hindered ester oil, and the general formula (5) is an example of a complex ester oil.

These ester oils may be used alone or in combination of two or more. Further, they may be contained as at least 50 wt% base oil, and the remainder may be supplemented with other well-known refrigerator oil. General formula,

[0063]

Embedded image (R ₁ · CH ₂ ) ₂ · C · (CH ₂ COOR ₂ ) ₂ ··· (1) (Neobentyl glycol (abbreviated as NPG) ester having two ester bonds in the molecule) Example) General formula,

[0064]

Embedded image R ₁ · CH ₂ · C · (CH ₂ · COOR ₂ ) ₃ ... (2) (Examples of trimethylolalkyl (propane, abbreviated as TMP) ester having three ester bonds in the molecule) ) General formula,

[0065]

Embedded image Examples of C. (CH ₂ —CHOOR ₂ ) ₄ ... (3) (abbreviated as “Pentaerythritol having four ester bonds in the molecule”) (PET))

[0066]

(R ₂ · OOCH ₂ C) ₃ · C · CH ₂ · O · CH ₂ · C (CH ₂ · COOR ₂ ) ₃ ··· (4) (di-containing 6 ester bonds in the molecule) Example of pentaerythritol (abbreviated as DPET) ester) General formula:

[0067]

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(Examples of Complex Esters Having Four or More Ester Bonds in the Molecule) In each of the above general formulas, R ₁ is H or an alkyl group having 1 to 3 carbon atoms, and R ₂ is an alkyl group having 5 to 5 carbon atoms. R 12 represents an alkyl group having 1 to ₃ carbon atoms, and n represents 0 or an integer of 1 to 5, respectively.

The above-mentioned general formulas (1) to (4) are esters of polyhydric alcohol and monocarboxylic acid. By arbitrarily selecting the kind of alcohol and the compound of a single or plural kinds of monocarboxylic acids, A desired viscosity grade can be obtained.

In the complex ester represented by the general formula (5), the chemical structure of the central dibasic acid (dicarboxylic acid) is represented by succinic acid (n = 2), glitalic acid (Glut), adipine Acid (abbreviated as AZP), pimelic acid, suberic acid, azelaic acid, sebacic acid (n = 8)
To obtain high viscosity and wide critical solution temperature range by selecting various molecular chains of polyhydric alcohol and terminal monocarboxylic acid and changing the mixing ratio (molar fraction). Can be.

These hindered ester oils and complex ester oils are used alone or in combination to adjust the viscosity to obtain a base oil.

The refrigerants having a critical temperature of 40 ° C. or higher and containing a chlorine-free carbon fluoride-based refrigerant as a main component in the present invention include hydrofluorocarbons and fluorocarbons. Specific examples of the hydrofluorocarbon include difluoromethane (R32), pentafluoroethane (R125), 1,1,2,2-tetrafluoroethane (R13
4), 1,1,1,2-tetrafluoroethane (R134a), 1,1,2
-Trifluoroethane (R143), 1,1,1-trifluoroethane (R143a), 1,1-difluoroethane (R152a), and monofluoroethane (R161).

Specific examples of the fluorocarbon include hexafluoropropane (C216) and octafluorocyclobutane (C318). Of these, especially 1,1,2,2
-Tetrafluoroethane (R134), 1,1,1,2-tetrafluoroethane (R134a), 1,1,2-trifluoroethane (R1
34), 1,1,1-trifluoroethane (R143a) and hexafluoropropane (C216) have boiling points close to those of conventional dichlorodifluoromethane (R12) and are preferred as alternative refrigerants.

In addition to using these hydrofluorocarbon or fluorocarbon-based refrigerants alone, it is also possible to use them as a mixture of two or more. By the way, the reason why the critical temperature of the refrigerant is set to 40 ° C. or higher is that a refrigerating device having a condenser temperature of 40 ° C. or higher is required.

The second object of the present invention is as follows: (3). Used in the refrigeration cycle, for compressing the refrigerant, a motor consisting of a rotor and a stator in a closed container for storing refrigerating machine oil, a rotating shaft fitted to the rotor, and this rotating shaft Via, a compressor unit connected to the motor is housed, and in a high-pressure container type compressor in which high-pressure refrigerant gas discharged from the compressor unit stays in a closed container, at a critical temperature of 40 ° C. or higher, 2 when viscosity is 40 ° C
70 cSt, 1 to 9 cSt at 100 ° C., and a compressor having a refrigerating machine oil based on an ester oil of a fatty acid having at least two ester bonds (—O—CO—) in a molecule, Achieved.

At least two ester bonds in the above molecule
The composition of the fatty acid ester oils
As described in detail in section (2).

In this type of high-pressure vessel type rotary compressor, the actual oil viscosity by dissolving Freon 134a at a gas pressure of 9 to 11 kg / cm ² abs and an oil temperature of about 100 ° C. is 1.0 to 1.0.
The viscosity at 40 ° C. is 2 to 7 so that it falls within 4.0 cSt.
The refrigerating machine oil of 0 cSt, preferably 5.0 to 32 cSt according to the above (2) is sealed in advance.

On the other hand, in the reciprocating compressor of the low pressure vessel type, (4). Used in the refrigeration cycle, for compressing the refrigerant, a motor consisting of a rotor and a stator in a closed container for storing refrigerating machine oil, a rotating shaft fitted to the rotor, and this rotating shaft In the compressor of the low pressure container type, in which the compressor unit connected to the motor is housed and the high pressure refrigerant gas discharged from the compressor unit is directly discharged out of the closed container, the critical temperature is 40 ° C. or higher. The viscosity is 2 to 70 cSt when the viscosity is 40 ° C., and 1 to 9 cSt when the viscosity is 100 ° C., and the base oil is an ester oil of a fatty acid having at least two ester bonds (—O—CO—) in the molecule. This is achieved by a compressor comprising machine oil.

At least two ester bonds in the molecule
The composition of the fatty acid ester oils
As described in detail in section (2).

In the reciprocating compressor of the low-pressure vessel type, the actual viscosity of the oil in dissolving the chlorofluorocarbon 134a at a suction gas pressure of 1.0 to 2.0 kg / cm ² abs and an oil temperature of 85 ° C. is 2.0 to 4.5 c.
5.0-1 when the viscosity is 40 ° C.
5 cSt, 2.0-4.5 cSt at 100 ° C.
The refrigerating machine oil described in the item (2) is previously enclosed.

The third object is achieved by adding an extreme pressure agent to the refrigerating machine oil described in (5) and (2).

The extreme pressure agent serves as an anti-wear agent for the sliding portion, and is, for example, an alkylpolyoxyalkylene phosphate represented by the general formula (6) or (7), or represented by the general formula (8). And dialkyl phosphates.

[0083]

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[0084]

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R ₄ : an alkyl group having 1 to 8 carbon atoms R ₅ : H or an alkyl group having 1 to 3 carbon atoms Molecular weight: 400 to 700

[0086]

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R ₆ : alkyl group having 8 to 16 carbon atoms These phosphate esters may be added alone or in combination of two or more. The practical addition amount is 0.05 to 10 wt%.

Further, together with the above-mentioned extreme pressure agent (anti-wear agent),
It is also effective to add an acid scavenger, an antioxidant, an antifoaming agent and the like.

The acid scavenger is added in order to remove the ester oil when the acid component is present in the refrigerating machine oil, whereby the ester oil is decomposed and becomes unstable. The acid scavenger reacts with an acid such as an epoxy compound. Compounds are preferred. In particular, compounds having an epoxy group and an ether bond such as diglycidyl ether compounds such as polyalkylene glycol diglycidyl ether, monoglycidyl ether compounds such as phenylglycidyl ether, and aliphatic cyclic epoxy compounds are preferable. The reason is that the epoxy group of these compounds captures an acid, and contributes to the improvement of the compatibility between the refrigerating machine oil and the refrigerant even if the ether bond is more or less.

The above-mentioned other additives include chlorine scavengers for eliminating the influence of residues such as chlorine-based cleaning agents used in the production of compressors and refrigeration equipment, and oxidative deterioration during distribution and storage of oil. Additives for preventing foaming, additives for preventing foaming, and the like, which can be dealt with by conventional general techniques, and are not specifically regulated here.

In order to achieve the fourth object, CFC 1
In a compressor using a chlorine-free chlorofluorocarbon-based refrigerator represented by 34a and a refrigerator oil comprising a fatty acid ester oil as a base oil according to the above (2), a glass is used as an electric insulating film constituting a motor portion. A crystalline plastic film with a transition temperature of 50 ° C or higher, or a composite film in which a resin layer with a high gas transition temperature is coated on a film with a low glass transition temperature, is used as an insulating coating winding. It is preferable to use a wire or an enamel wire in which a layer having a low glass transition temperature is coated as a lower layer and a layer having a higher glass transition temperature is coated as an upper layer.

As a practical insulating film,
Polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, polyethylene naphthalate, at least one kind of insulating film selected from the group of polyamide imide and polyimide is preferable, and as the enamel coating, the group of polyester imide, polyamide and polyamide imide At least one kind of insulating layer selected from

[0093] In a refrigeration cycle using this compressor, the following configuration is desirable. That is, when a chlorofluorocarbon-based refrigerant typified by chlorofluorocarbon 134a and a refrigeration oil based on the fatty acid ester oil described in (2) above are used in combination, a dryer is provided in the refrigeration cycle. It is preferable that the pore size is 3.3 angstrom or less, 25 ° C.
The carbon dioxide absorption container at a carbon dioxide partial pressure of 250 mmHg is made of synthetic zeolite composed of a composite salt of silicic acid and alkali metal aluminate having a concentration of 1.0% or less.

[0094]

A hindered ester or complex ether having two or more ester bonds in the molecule and having a viscosity of 2 to 70 cSt at 40 ° C, preferably 5 to 32 cSt.
cSt, 1 to 9 cSt at 100 ° C., preferably 2 to 9 cSt
In a refrigeration cycle using a chlorofluorocarbon-based refrigerant represented by chlorofluorocarbon 134a, a compressor having 6 cSt of the refrigeration oil of the present invention has good compatibility with the refrigerant in all temperature bands of each part used. Therefore, the two-layer separation state of the refrigerant and the refrigerating machine oil does not exist.

Therefore, (1) there is no two-layer separation in the oil storage section in the compressor, and lubrication to the bearing sliding section is guaranteed. (2) In the state where the CFC gas discharged from the compressor is liquefied by the condenser or in a low temperature environment of −30 ° C. or lower in the evaporator, the oil always has a low viscosity CFC 134.
Since it exists in a state of being dissolved in a and has a low viscosity as a whole, the return of oil to the compressor is improved. Therefore, since the oil level drop phenomenon of the compressor is eliminated, the supply of oil to the bearing sliding portion can be ensured, and the problem of biting and seizure can be solved.

Further, this refrigerating machine oil has a saturated water content of less than one-tenth, which is a drawback of the conventional polyoxyalkylene glycol oil, and has a large effect of improving the oxidative deterioration stability. Some volume low efficiency is 10 ¹³
Ωcm. Therefore, in the refrigerant compressor accommodating the motor unit in the pressure vessel and the refrigeration apparatus using the same, the chlorofluorocarbon 134a and the refrigeration oil of the present invention are not separated, and both the performance and the reliability of the compressor are excellent. Show the features.

Since the refrigerating machine oil is also excellent in compatibility with the conventional chlorofluorocarbon refrigerants such as chlorofluorocarbon 12 and chlorofluorocarbon 22, a part of the chlorofluorocarbon 134a may be partially replaced with the conventional chlorofluorocarbon refrigerant containing chlorine. It can be replaced with a refrigerant and used as a mixture.

Next, of the refrigerating machine oil of the present invention, 40
Oil having a preferred oil viscosity of 5 to 32 cts is sealed in a high-pressure container type rotary compressor, and when the coefficient of performance of the compressor is observed, the point where oil of 15 cSt is used shows a peak,
5 to 32 cSt is approximately 1.4 or more as a coefficient of performance representing the performance of the compressor, and if the combination of the conventional Freon 12 and alkylbenzene oil is 1, the range is 0.95 to 0.93, which is practically no problem. It is shown that.

Further, when the viscosity at 40 ° C. was 56 cSt, it was found that the refrigerating machine oil of the present invention was superior to the polyoxypropylene glycol oil in the coefficient of performance of the compressor. This is because the oil itself has an ester bond that is mainly molecularly oriented on the surface of the iron-based sliding part of the compressor shaft and bearing part to improve lubricity, and the property that the oil is easily soluble in Freon 134a. And the action of improving the mechanical loss works together to improve the coefficient of performance of the compressor.

On the other hand, the low-pressure vessel type reciprocating compressor operates at a low pressure of 1 to ² kg / cm ² abs in the vessel, so that the fluctuation range of the dissolved amount of fluorocarbon 134a and the actual viscosity is small. Therefore, characteristics due to the types of the refrigerant and the refrigerating machine oil are unlikely to appear, and the viscosity is 5 to 15 cSt at 40 ° C. and 2 at 100 ° C.
Those in the range of ４4 cSt were found to be good in reliability and performance.

Next, in the refrigerating machine oil of the present invention, as an extreme pressure agent, for example, OH is contained in a molecule such as alkyl polyoxyalkylene phosphate and dialkyl phosphate.
When the primary and secondary strong phosphoric acid esters having residual groups are blended in an appropriate amount of 0.05 to 10% by weight, they are molecularly oriented on the surfaces of the iron-based sliding parts constituting the shaft and the bearing of the compressor. By removing the lubricating oil film of the ester bond, a stronger phosphoric acid ester chemisorption film can be formed, and the lubricating property of the sliding portion can be improved, and biting and seizure can be prevented. .

The lubricating properties of the refrigerating machine oil of the present invention to which the extreme pressure agent was added were examined and examined. In a Falex test (oil seizure test) assuming that Freon 134a was not dissolved, the limit seizure surface pressure was determined. Has been achieved, and chlorofluorocarbon 13
As for the wear amount of the iron-based sliding member of the refrigerating machine oil in which 50% of 4a was dissolved, the wear amount was reduced to one-fifth as compared with the non-added product.
It was possible to reduce it below. The appropriate range of the addition amount is 0.05 to 10 wt% as described above. In addition,
The test results of the wear amount will be specifically described in the section of Examples later, but are as shown in FIG. 6, and the effect of the addition to reduce the wear amount is remarkable.

Further, additives such as an acid scavenger, an antioxidant, and a foaming agent which are usually used together with the above extreme pressure agent can be blended, and they act more effectively.

Next, with respect to the electric insulating material of the refrigerant compressor using both the chlorofluorocarbon 134a and the refrigerating machine oil of the present invention, the insulating film, which is the electric insulating system material of the motor part, has a crystal transition temperature of 50 ° C. or higher. Plastics film, for example, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ethyl ketone, polyethylene naphthalate, polyamide imide, polyimide or on a film having a low glass transition temperature, a resin layer having a high gas transition temperature The composite film to be coated is less likely to cause deterioration in tensile strength characteristics and electrical insulation characteristics, and falls within a range where there is no practical problem. This is because the amount of water taken in and the amount of generated acid are very small as compared with the conventional polyoxyalkylene glycol oil, so that deterioration of the film itself due to hydrolysis hardly occurs.

Similarly, for the magnet wire used in the motor section, an enamel coating having a glass transition temperature of 120 ° C. or more, for example, a single layer of polyesterimide, polyamide, polyamideimide, etc. An enamel coating in which a material having a high glass transition temperature is composited in the upper layer has a low degree of degradation of the film due to hydrolysis, generation of cracks, softening, swelling, a decrease in dielectric breakdown voltage, etc. as in the case of the above-described film, and is reliable in practical use It turned out to be useful for improvement. Some enamel coatings of magnet wire have self-lubricating properties and add internal lubricant and external lubricant for the purpose of improving electrical workability. The characteristic inherits the above-mentioned basic structure as it is.

Finally, as a preferred configuration example when the compressor of the present invention is applied to a refrigeration cycle, the operation of a dryer constituting a part thereof will be described. As shown in FIG. 10, a dryer 45 is desirably disposed between the condenser 41 and the expansion mechanism 42. This is because the ester compound of the refrigerating machine oil component and the CFC-based refrigerant held by the compressor are disposed within the refrigeration cycle. And the ester compound is partially compressed with the refrigerant gas by the compressor 40 to become high temperature and may be partially decomposed during a long period of use to generate moisture. To prevent clogging of the capillary of the refrigeration cycle and freezing on the evaporator to degrade heat conduction.

In the refrigerating cycle, the desiccant to be charged into the dryer when Freon 134a and the refrigerating machine oil of the compressor of the present invention coexist is described. In the present invention, the pore diameter is 3.3 angstrom or less, 25 Å or less. ℃, carbon dioxide absorption capacity at carbon dioxide partial pressure 250mmHg is 1.0%
The following synthetic zeolites comprising a silicic acid and an alkali metal aluminate complex salt are preferred. Examples of such a zeolite include XH-9 and XH-trade names manufactured by Union Showa Co., Ltd.
600, etc., all of which have low fluoride ion adsorption amounts.

The carbon dioxide absorption capacity was 1.5%.
In the above, the fluorine ion absorption amount reaches 0.24% or more, and the adsorption characteristics and breaking strength as molecular sieves are reduced. In addition, the corroded crystal pickles cause clogging of the refrigeration cycle piping and damage to the bearing sliding portion of the compressor. From this viewpoint, the present invention in which the pore diameter is controlled by the carbon dioxide gas absorber does not have such a concern, and makes it possible to construct a highly reliable refrigeration apparatus.

[0109]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. 1 to 6 and Tables 1 to 4. <Embodiments 1 to 17> This embodiment shows an embodiment for achieving the first object. In a hermetic rotary compressor according to a refrigeration cycle and a refrigerant compressor, Freon 134a is used as a refrigerant. The refrigerating machine oil used has a viscosity of 2 to 70 cSt at 40 ° C., more preferably 5 to 32 cSt.
An analysis will be made on an example in which an ester oil having a viscosity of 1 to 9 cSt, more preferably 2 to 6 cSt at 100 ° C., and having two or more ester groups in the molecule, as shown in Table 1, is used in combination. Table 1 also shows conventional refrigerator oils for comparison.

FIG. 1 shows a two-phase separation temperature diagram for explaining the compatibility between Freon 134a and refrigerating machine oil. Fron 134a and refrigerating machine oil are sealed in a high-pressure glass container, and the melting ratio and each temperature are shown. It summarizes the results of visual observation of the state of two-layer separation for each case. The horizontal axis shows the concentration of oil in Freon 134a, and the vertical axis shows the two-layer separation temperature. The first target value shown in this figure is a lower critical melting temperature required by a refrigerating apparatus having a medium evaporator temperature (0 ° C. or less) such as a dehumidifier, and a second target value. It shows the lower critical melting temperature (all specified values) required by a refrigerating apparatus such as a refrigerator having a low temperature evaporator temperature (-30 ° C. or lower).

A conventional refrigerating machine oil, for example, Nippon Sun Oil Co., Ltd.
Brand name Suniso 4GSD (naphthenic) or Z300
(Alkylbenzene type) does not dissolve, and in the case of PAG56 (polyalkylene glycol) (trade name, also manufactured by Nippon Sun Oil Co., Ltd.), the lower critical dissolution temperature (indicated by L1) is -6.
0 ° C. and the upper critical melting temperature (indicated by U1) is 35 ° C. Ester oil having two or more ester groups in the molecule of the present invention has a lower critical solution temperature (indicated by L2)
Indicates that the critical dissolution temperature is excellent at -70 ° C and the upper critical dissolution temperature (U2) is 70 ° C or more. Among them, the lower critical melting temperature is a practically important factor in the heat exchanger of the refrigerating apparatus, and the upper critical melting temperature is a practical factor in the refrigerant compressor.

That is, FIG. 10 shows a refrigeration cycle configuration diagram of the refrigeration apparatus. In the refrigeration apparatus including the refrigerant compressor 40, the condenser 41, the dryer 45, the expander 42, and the evaporator 43, When the refrigerating machine oil is operated in combination with Freon 134a, the conventional naphthenic mineral oil suniso 4GSD and the alkylbenzene oil Z300A shown in Conventional Examples 1 and 2 are used.
(Same name as manufactured by Nippon Sun Oil Co., Ltd.) states that when a large amount of refrigerant is present and the refrigerant lays down in the compressor, the refrigerant layer with a higher density becomes Since it is unevenly distributed in the upper layer, as shown in a longitudinal sectional view of a main part of the refrigerant compressor (an example of a closed type rotary compressor) in FIG. 7, oil supply to the shaft 4A, the main bearing 5, and the sub bearing 6 is performed as follows. The refrigerant layer unevenly distributed in the lower layer is sucked from the suction port 14 of the pump. Therefore, the viscosity of the refrigerant layer is smaller than that of the refrigerating machine oil, and when the oil is supplied to the bearing portion, the oil film is thin and the metal contact is likely to occur. In addition, since the temperature of the sliding friction surface instantaneously rises, the refrigerant gasifies, and the condition shifts to more severe conditions. When this phenomenon is repeated, damage occurs due to biting and seizure of the shaft and bearing,
The performance as a refrigerant compressor will be lost.

Further, the heat exchanger of the refrigerating apparatus shown in FIG.
For example, when used for the evaporator 43 used at 0 to -60 ° C,
The refrigerating machine oil discharged together with the refrigerant gas from the compressor 40 causes two-layer separation in the evaporator 41, and the refrigerating machine oil adheres to the inner wall of the heat exchanger pipe, and the refrigerating machine oil stays and exchanges heat. Since the heat insulation phenomenon of the vessel occurs, the cooling performance of the refrigerating apparatus is significantly impaired, which is not practical. In this regard, the polyalkylene glycol shown in Conventional Example 3 in Table 1 is advantageous in that the lower critical dissolution temperature is −60 ° C. and thus does not cause two-layer separation in the evaporator 41, Since the temperature of the machine 40 is at least 80 ° C, the upper critical melting temperature is 3
5, the two-layer separation completely occurs, and when the bearing is refueled as in Conventional Examples 1 and 2, damage due to biting and seizure between the shaft and the bearing occurs. You will lose performance.

In a refrigerant compressor provided with a hermetic motor, for example, a rotary compressor shown in FIG.
Naturally, characteristics as an electrical insulating oil are required.

FIG. 2 shows the relationship between the water absorption and the volume resistivity of the ester oil of the present invention, the conventional mineral oil and the polyalkylene glycol. Even in a state where the water content is controlled to 500 ppm or less, the conventional polyalkylene glycol is not affected by the ether bond in the molecule.
Undesirably low value of ¹² Ωcm or less.

On the other hand, the one into which the ester group of the present invention was introduced exhibited a high insulation performance of 10 ¹³ Ωcm or more.
Since the standard value of "ISC2320" electrical insulating oil was satisfied, it was found that the material was sufficiently practical. In addition,
The conventional mineral oil has high insulation performance,
It is not practical because of poor compatibility with 4a.

Next, the relationship between the type, the chemical structure, and the lower critical solution temperature of the ester oil compatible with Freon 134a will be described in detail with reference to Table 1.

The type of the ester oil having two or more ester groups in the molecule shown in the present invention means a monobasic organic acid or an ester of a polybasic organic acid and a polyhydric alcohol, and is a typical example. Neobentyl glycol-based ester, trimethylolpropane (or ethane) as ester oil
Ester, pentaerythritol ester, hindered ester oil, complex ester, and the like, and the relationship between the name of a typical chemical compound, viscosity, and critical dissolution temperature is shown.

[0119]

[Table 1]

[0120] Note that in the sample names in Table 1 have those simplified displays the name of the chemical synthesis of ester oils, for example if the NGP / n-C ₈ of Example 1, NGP neopentyl glycol , NC ₈ is an abbreviation for a normal organic acid (linear fatty acid) having 8 carbon atoms, and represents an ester of neopentyl glycol and a normal organic acid (linear fatty acid) having 8 carbon atoms. In addition, the NGP / i-2EH of Example 3
Then, i-2EH is an abbreviation for iso-2-ethylhexyl acid, neopentyl glycol and iso-2-ethyl.
Represents an ester with hexylic acid (a fatty acid having a branched chain).

As a result, (1) neopentyl glycol esters (NPG) are, as shown in Examples 1 to 4, esters of neopentyl glycol of dihydric alcohol and monocarboxylic acid which is a monobasic organic acid. Yes, it is characterized by having two ester groups in the molecule. These chemical structures show an important relationship with the compatibility with Freon 134a and the viscosity characteristics of oil.

That is, the monocarboxylic acid has 7 to 7 carbon atoms.
8 are good and the lower critical solution temperature is -29.
~ -70 ° C, viscosity at 40 ° C is 2.8-7.0 cSt.
Met.

The lower critical solution temperature is lower as the number of carbon atoms of the monocarboxylic acid (fatty acid) is smaller, and the iso-2-ethylhexyl (i-2E) of Example 3 having a branched chain in the molecule is used.
H) Isoheputan acid and Example 4 (I-C ₇₎ towards the acid is lower, it was found to be advantageous. Further, Example 5 is an example in which the number of carbon atoms (11) of the carboxylic acid is increased in order to increase the viscosity.
9 cSt, the lower critical solution temperature was found to be the limit at -40 ° C.

(2) Next, trimethylpropanol (TMP) esters having three ester bonds in the molecule will be described with reference to Examples 6 to 10.

An ester oil obtained by condensation of a trihydric alcohol, trimethylolpropane (TMP), with a monobasic organic acid, monocarboxylic acid, has three ester groups in the molecule, and has a carbon number of monocarboxylic acid. For 6 to 8, the viscosity at 40C is in the range of 10.8 to 32.2 cSt, and the lower critical melting temperature is in the range of -20 to -60C. Those having a temperature of −20 ° C. or lower include those of heptanoic acid (nC ₇ ) of Example 6, octanoic acid (nC ₈ ) of Example ₈ , iso-2-ethyl hexic acid (i-2EH) of Example 9, Those below -60 ° C
Hexane (n-C ₆₎ acid of Example 7, an ester oil Isoheputan acid Example 10 (i-C _7). Here, too, the lower critical melting temperature is characterized in that it is lower as the number of carbon atoms is smaller, and is lower as the number of carbon atoms contains the branched chain (iso).

(3) As shown in Examples 11 to 13, the ester oil obtained by condensation of pentaerythritol (PET) of a tetrahydric alcohol with a monocarboxylic acid has four ester groups in the molecule as shown in Examples 11 to 13. Has 6 or more carbon atoms
For 8 pieces, the viscosity at 40 ° C. is 17.5 to 52.0 cSt.
And the lower critical solution temperature is -8 to -44 ° C.
And the temperature is shifted to a higher temperature side with respect to the ester oils of the above-mentioned dihydric alcohol and trihydric alcohol. Among them, those having a lower critical dissolution temperature of −40 ° C. or lower are ester oils with hexane (nC ₆ ) acid of Actual Example 11 and iso-heptane (i-C ₇ ) acid of Example 13. . Here, too, the lower critical solution temperature is characterized in that it is lower as the number of carbon atoms is smaller, and lower as it contains a branched chain.

(4) Next, as a method for containing four ester groups in the molecule, the esterification is carried out by condensing a polyhydric alcohol and further a monocarboxylic acid, centering on a dicarboxylic acid, which is a representative of a dibasic organic acid. By lowering the viscosity, the lower critical dissolution temperature is lowered and the viscosity is easily increased. A complex ester thus designed is a complex ester, which will be described in Examples 14 to 17 of the present invention.

In Example 14, dicarboxylic acid glutaric acid (abbreviated as Glut), dihydric alcohol neopentyl glycol (NPG), and monocarboxylic acid hexane (C ₆ )
It is a complex ester of acid and has a viscosity of 3 at 40 ° C.
2.6 cSt, 100 ° C. was 5.9 cSt, and the critical melting temperature was −75 ° C. or less.

Example 15 shows an example in which an intermediate viscosity grade was prepared by mixing Examples 4 and 16, and also in this case, it was found that there was no significant change in the lower critical melting temperature.

In Example 16, dicarboxylic acid adipic acid (abbreviated as AZP), dihydric alcohol neopentyl glycol (NPG), and monocarboxylic acid decanoic acid (n-
Complex ester of C ₁₀ ), Example 17 shows a complex ester of dicarboxylic acid glutaric acid (Glut), dihydric alcohol neopentyl glycol (NPG), monocarboxylic acid iso-hexanoic acid (i-C ₆ ). 54.5-56.6 cSt at 40 ° C, 100 ° C
Viscosity of 7.3 to 8.6 cSt, lower critical melting temperature is -60 ° C
It turned out to be excellent.

In the complex ester, the number of carbon atoms C _{2 to} C ₁₀ of the dicarboxylic acid of the dibasic organic acid and the number of carbon atoms C _{5 to} C ₁₀ of the monocarboxylic acid of the monobasic acid are arbitrarily set. It is shown that when a desired molar ratio is selected and condensed with a polyhydric alcohol, one having an arbitrary viscosity can be synthesized.

By arranging these examples, esters can be represented by the following general formula. Neopentyl glycol ester:

[0133]

Embedded image (R ₁ · CH ₂ ) ₂ · C · (CH ₂ COOR ₂ ) ₂ (1) Trimethylolpropane (or ethane) ester:

[0134]

Embedded image R ₁ · CH ₂ · C · (CH ₂ · COOR ₂ ) ₃ ... (2) Pentaerythritol ester:

[0135]

Embedded image C · (CH ₂ —CHOOR ₂ ) ₄ (3) Complex ester:

[0136]

Embedded image

Further easily obtained dipentaerythritol esters:

[0138]

Embedded image _{(R 2 · OOCH 2 C)} 3 · C · CH 2 · O · CH 2 · C (CH 2 · COOR 2) 3 ... (4) where, R _1: H or a 1 to 3 carbon atoms Alkyl group R ₂ : an alkyl group having 5 to 12 carbon atoms, in which plural kinds having different carbon numbers can be mixed R ₃ : an alkyl group having 1 to ₃ carbon atoms n: represented by 0 or an integer of 1 to 5 It was possible to design an arbitrary viscosity by selecting the types of polyhydric alcohol and carboxylic acid which is a basic organic acid.

Further, in order to obtain an intermediate viscosity, it was possible to easily adjust the viscosity by blending a low-viscosity oil and a high-viscosity oil.

As described above, in a refrigeration system using a chlorofluorocarbon-based refrigerant such as chlorofluorocarbon 134a, the first one of the hindered ester and the complex ester having two or more ester bonds in the molecule.
When the viscosity of the oil at the lower critical dissolution temperature of 0 ° C. or less, which is the target value of the oil, and the oil of the second target value, the lower critical dissolution temperature of -30 ° C. or less, is 40 ° C., 2 to 70 cS
t, more preferably 5 to 32 cSt, 1 at 100 ° C.
By selecting a compressor of 〜9 cSt, more preferably of 2 to 6 cSt, a compressor and a refrigeration apparatus having basically satisfactory performance and reliability were obtained.

These ester-based refrigerating machine oils are Freon 13
It has been confirmed that not only 4a, but also chlorine-free refrigerant gas such as Freon 152a (difluoroethane CH ₃ CHF ₂ ) has good compatibility, and it is effective for high performance and high reliability of refrigeration equipment. there were.

Further, since these ester oils of the present invention are well soluble in conventional chlorine-based refrigerants such as Freon 12 and Freon 22 (chlorofluorocarbon-based refrigerants), a part of them is used as a mixture. In some cases, it was confirmed that it was effective.

However, since these conventional fluorocarbon refrigerants containing chlorine are subject to use restrictions due to the problem of environmental destruction, it is desirable that the content be 50% or less, and the ester oil of the present invention be at least 50% or more.

Next, an embodiment of a refrigeration apparatus for achieving the second object of the present invention will be described.

<Embodiment 18> The rotary compressor shown in FIG. 7, which is a refrigerant compressor, was incorporated into the refrigerating apparatus shown in FIG.
Table 1 shows the relationship between the viscosity of the refrigerating machine oil stored in the compressor and the coefficient of performance (COP), which is the ratio between the refrigerating capacity of the compressor and the input, at 00 ° C. and a discharge gas temperature of 9.5 ° C. to 10 kgf / cm ² G.
The measurement was carried out using ester oils of typical viscosity grades exemplified in FIG. 3, and the results are shown in FIG.

In FIG. 3, the horizontal axis represents the actual viscosity of the refrigerating machine oil stored in the rotary compressor, and the vertical axis represents the coefficient of performance (expressed as a relative value) of the compressor. It shows the relationship between the refrigerating machine oil actual viscosity and the coefficient of performance (COP) for an alkylbenzene oil (Sniso Z-300A) having a viscosity of 5 to 56 cSt, a conventional polyalkylene glycol and Freon 12 used. is there.

According to this, the conventional CFC 12 and 40 ° C.
When the coefficient of performance of Z-300A (alkylbenzene oil) having a viscosity of 56 cSt at the time of
The combination of polyalkylene glycol (PAG56) and Freon 134a in Conventional Example 3 was as low as 0.859, indicating that the energy efficiency was reduced by about 14%.

On the other hand, at 40 ° C. in Example 17 of the present invention.
At that time, the complex ester oil having a viscosity of 56.6 cSt was as good as 0.906. This is because the viscosity of the refrigerating machine oil at the time of melting the Freon 134a under the same operating conditions is as low as 4.35 cSt, so the journal bearing theory represented by the equation (9) indicating the friction coefficient described in the section of the prior art earlier. It is thought that the effect of reducing friction loss based on the above and the power of stirring oil and the heat radiation effect also move.

Next, when the coefficient of performance of the ester oil of the present invention was compared with that of the oil of 5 to 32 cSt (40 ° C.) in a lower range, the viscosity was 32.6 cS in Example 14.
t (40 ° C.) was 0.926, and 14.9 in Example 5.
0.966 for cSt (40 ° C.), 1 in Example 10
In the case of 4.9 cSt (40 ° C.), the order of 0.973 improved sequentially, and in the case of 5.5 cSt (40 ° C.) in Example 4, it was 0.95.
3, which showed a slight decrease tendency.

From these results, it is found that the ideal ester oil suitable for the rotary compressor is 5 to 32%, including the best value of the viscosity at 40 ° C. of about 14.9 cSt.
(Accurately, 5.5 to 32.6) cSt ester oil containing two or more ester bonds in the molecule as described above.

<Embodiment 19> Next, Freon 134a and the refrigerating machine oil shown in Table 1 of the present invention were used in combination with a low-pressure vessel type reciprocating compressor, and the refrigerating machine was assembled in a refrigerator as a refrigerating apparatus to obtain high-temperature reliability. The test (in-case pressure 1.6 kg / cm ² abs, case temperature 85 ° C., 100 V, 50 Hz) was performed.

FIG. 4 shows the results. The abscissa indicates the actually measured viscosity of the refrigerating machine oil stored in the compressor, and the ordinate indicates the coefficient of performance (COP) indicating the performance of the compressor. The viscosity of the refrigerating machine oil at 40 ° C. is shown in the example of Table 1 in 5.
The characteristics of the relationship between the actual viscosity and the coefficient of performance in the actual operation of the sample refrigerating machine oils of 5, 14.9, 22.0, 32.6 and 56.6 cSt are plotted, and are almost linearly connected.

The results show that the low-viscosity reciprocating compressor of the reciprocating type has a higher coefficient of performance as the viscosity of the refrigerating machine oil is lower. The actual viscosity is 2 to 4.2 cSt, and the viscosity of the refrigerating machine oil at 40 ° C. 5.5 to 14.9 cSt
Can be said to be superior. Note that the actual viscosity is 2 cSt.
When it becomes smaller, the roughness of the sliding parts surface of the compressor becomes
Conventional cast iron and iron-based sintered materials have a limit in finishing accuracy, tend to enter a boundary lubrication region involving metal contact, lower the coefficient of performance, and tend to have poor bearing reliability.

Embodiment 20 Next, lubricating properties of a refrigerant compressor of a refrigerator for achieving the third object of the present invention will be described with reference to the following embodiments.

As a method of evaluating the lubricity, the seizure load in the atmospheric Falex test and the CFC 134a
A high-pressure atmosphere friction test was performed to determine the seizure load in the refrigerator oil in which 0% was dissolved, and a correlation diagram of the results is shown in FIG. Note that the seizure load is obtained by applying a load from both sides to a rotating sample pin, and displaying the load at the time of seizure in pounds (lb).

Here, the refrigerating machine oil used in the refrigerating machine of the present invention is exemplified by the ester oil of trimethylolpropane (TMP) and iso-heptane (i-C ₇ ) acid of Example 10 shown in Table 1. The relationship between the kind and amount of the extreme pressure agent added to the ester oil and the lubricating properties was determined.
The material of the test piece used for the lubrication evaluation was such that the pin in the Falex test was JIS-standard SNC-21 (nickel-chrome steel), and the block was JIS-standard SU.
M41 (sulfur free-cutting steel) is a standard type. On the other hand, a high-pressure atmosphere friction test is performed on a shaft material (eutectic graphite cast iron) and a roller material (eutectic graphite cast iron) which have been used in rotary compressors. The material is evaluated by a friction test between cylinders, and is expressed by a load when a seizure phenomenon occurs.

As shown in the sample No. 1 in FIG. 5, the ester oil without the extreme pressure agent (oil of Example 10) had a Falex baking load of 700 (lb) and 9 in the atmosphere of Freon 134a.
In contrast to a low value of 0 kgf / cm ² , Sample No. 2 was composed of a dialkyl phosphate ester which is one of acidic phosphate esters having an active OH group in the molecule as an extreme pressure agent. 1% of Sakai Chemical's trade name Chiclex H-10
The addition of 1% of an ester compound of alkylene glycol and phosphoric acid (butyl polyoxypropylene phosphate) in sample No. 3 further improved the Falex baking load by 400 (lb). 1100 (lb), 9 in the atmosphere of Freon 134a
0kg / cm ² improved to confirming the effect of 180kg / cm ^2.

That is, a phosphorus compound such as an acidic phosphoric acid ester or an alkylene glycol phosphoric acid ester compound effectively acts as an extreme pressure agent, and effectively acts as an extreme pressure effect for preventing seizure regardless of the presence or absence of Freon 134a. It was proved that.

Next, in the Falex test, the load was fixed at a fixed value of 100 (lb), a test was continuously performed for a maximum of 120 minutes, and the wear amount of the pin as the iron-based test piece was measured. The results are as shown in FIG. 6. The oil of Sample No. 4 without the extreme pressure agent was worn by 25 mg, whereas the oil containing the above-mentioned phosphorus compound was the same as Sample No. 7 and Sample No. 4. As shown in No. 8, all were as small as 0.4 mg and could be reduced to 1/5 or less. The amount of the phosphorus compound added was determined according to the sample No. As shown in FIG. 5, the effect is obtained from around 0.05 wt%, and the effect is improved as the amount is increased. However, if it exceeds 10 wt%, the effect of improving lubricity reaches saturation, which is economically disadvantageous and therefore impractical.

The viscosity of the oil was determined to be 14.9 cS of the sample No. 4.
From t (40 ° C.), 56.6 cSt (40
C)), the amount of wear was also reduced.

As described above, 0.05 to 10 wt% of a phosphorus compound such as an acid phosphate, a phosphate and an alkylene glycol phosphate as an extreme pressure agent is added to the refrigerator oil of the present invention. It was also found that the seizure load, abrasion resistance, and lubricity of the iron-based sliding member could be drastically improved by adjusting the viscosity of the oil instead of adding the extreme pressure agent to increase the viscosity. In particular, it exhibits excellent performance when a chlorofluorocarbon-based refrigerant such as chlorofluorocarbon 134a does not exist.

<Embodiment 21> As an embodiment for achieving the fourth object of the present invention, the electric insulating material used for the hermetic motor of the compressor was prepared in the presence of Freon 134a and the refrigerating machine oil of the present invention. Table 2 shows the results of evaluating the behavior.
This will be described with reference to Table 3.

For the evaluation of the Freon 134a and the refrigerating machine oil, in order to eliminate the influence from the outside, the state of the property deterioration of the magnet wire (enamel coated wire) and the insulating film material was observed by a shield tube test.

(1). Insulation characteristics of magnet wire (enamel coated wire): The magnet wire test was conducted on a shielded tube test at 150 ° C for 40 days for two types of a 5% elongated product and a twisted pair test piece. An explanation will be given below using the listed results.

[0165]

[Table 2]

The CFC 134 shown in the prior art 3 in Table 1 is used.
According to the shield tube test results of the combination of polyalkylene glycol of the refrigerating machine oil and Freon 134a which are said to be compatible with the polyester wire (PEW) of sample No. 9 and the ester imide wire (EIW) of sample No. 10 in Table 2, In the case of -R), crazing (cracking) occurred in all cases with respect to the 5% elongation line, and the retention of the dielectric breakdown voltage of the twisted pair test piece was remarkably reduced to 30 to 32%.

On the other hand, a similar evaluation was conducted using the glutaric acid (Glut) of Example 17 which is the refrigerating machine oil of the present invention exemplified in Table 1.
And the composite ester oil of neopentyl glycol (TPG) and Isohekisan acid (i-C ₆₎ Freon 13
4a, the results of the above-described conventional sample
As shown in Sample Nos. 11 and 12, the polyester wire (glass transition temperature: Tg is shown in Table 2) and polyester imide wire which showed deterioration in Nos. In addition, the retention ratio of the dielectric breakdown voltage was as high as 95% or more, and it was found that the degree of deterioration of the magnet wire was extremely small. The reason for this is that the refrigerating machine oil of the present invention has a small amount of water retained at an early stage, has excellent thermal stability, and is difficult to generate an acidic substance that promotes hydrolysis, and has the effect of improving. It is what has brought.

Sample No. 13 was obtained by further coating and compounding a polyamide imide layer on the ester imide wire of sample No. 12, and sample No. 14 was prepared by using polyamide imide alone (A
IW) coatings showed good properties. In this way, the magnet wire in which the layer having a high glass transition temperature is coated on the layer having a low glass transition temperature has an effect that the upper layer film effectively acts as a protective action against erosion of Freon 134a and refrigerating machine oil. It was found that it contributed to the improvement of the reliability of the machine.

(2). Insulation Characteristics of Insulating Film: Next, a shield tube test was performed on the insulating film of the motor at 130 ° C. for 40 days to evaluate the appearance and the tensile strength retention. Table 3 shows the results.

[0170]

[Table 3]

In the case of a general polyester film (trade name: Lumirror X ₁₀ manufactured by Toray Co., Ltd.) used for a hermetic motor of a compressor, in the case of the conventional polyalkylene glycol oil shown in Sample No. 15, the oligomer component was deposited in the oil. Was observed, and the retention of tensile strength was 83%.

On the other hand, in the combination of the complex ester oil and Freon 134a of Example 17 of the present invention, Lumirror X ₁₂ of Sample No. 16 and PA-polyamideimide-coated polyester of Sample No. 17 were used. 61M
(Trade name of Hitachi Chemical Co., Ltd.), polyphenylene sulfide (PPS) film of sample No. 18, sample No. 1
In any of the polyetheretherketone (PEEK) films of No. 9, oligomers did not break out, and the tensile strength retention was excellent at 89% or more.
It has been found that the reliability can be remarkably improved as an electrical insulation system for a compressor using a.

That is, in an environment where Freon 134a and a refrigerating machine oil having two or more ester groups in the molecule of the present invention coexist, a polyester film having a glass transition temperature of 65 ° C. or more, a polyamideimide-coded polyester film and a PPS film, Completion of the insulation system of the Hermetics motor by appropriately selecting the PEEK film is a problem with the oil of the conventional example 3 shown in sample No. 15. It has been found that the problem of performance and the practical problem of long-term reliability in refrigeration equipment can be solved.

<Embodiment 22> Next, a preferred application example of the compressor holding the refrigerating machine oil of the present invention will be described. Among the refrigeration systems equipped with compressors, especially those that use a heat exchanger at 0 ° C or lower, the management of moisture in the refrigeration system has an important effect on the cooling performance and the quality of the electrical insulation material. It is known that the establishment of technology for the water removal method is an indispensable requirement on a refrigeration system.

As shown in FIG.
In the refrigeration cycle configured, the Freon 134a gas discharged from the compressor 40 is condensed by heat radiation in the condenser 41 to become a liquid refrigerant, and the high-temperature, high-pressure liquid refrigerant is cooled by the next expansion mechanism 42 to a low-temperature, low-pressure liquid refrigerant. In the process of becoming wet steam and being sent to the evaporator 43, a dryer 45 is provided between the condenser 41 and the expansion mechanism 42, and is adsorbed and removed by a desiccant represented by synthetic zeolite. It is important to properly select the type of desiccant in the use environment in which the refrigerating machine oil and Freon 134a coexist, and their compatibility will be described based on the examples in Table 4.

[0176]

[Table 4]

All the drying agents tested were manufactured by Union Showa
This is a synthetic zeolite called Molecular Sieves (trade name) manufactured by K.K. is there.

The compatibility of the synthetic zeolite with Freon 134a and the refrigerating machine oil of the present invention will be described based on the shield tube test results shown in Table 4.

Sample No. 20 (conventional example, trade name 4ANR)
The synthetic zeolite containing a sodium salt of aluminate or silicic acid as a main component shown in G) has a fluorine ion adsorption amount of 1.0.
It was as large as 5%, and it was found that problems such as reduction in strength due to the reaction of the synthetic zeolite and powdering occurred. Also. Sample No. 21 (conventional example, trade name 4AXH-6) and Sample No. 21 mainly containing sodium and potassium salts of aluminate and silicic acid
22 (Comparative Example, trade name XH-7) has a carbon dioxide adsorption capacity of 4.5 to 1.5% and a fluorine ion adsorption amount of 0.5%.
This was reduced to 24%. However, the fluorine ion adsorption amount is still large for practical use.

Further, Sample No. consisting of synthetic zeolite mainly composed of potassium and sodium salts of aluminate and silicic acid was used.
23 (Example, trade name XH-600) and Sample No. 2
Sample No. 3 (Example, trade name XH-9) had a carbon dioxide gas adsorption capacity of 0.2%, and the fluorine ion adsorption amount was sharply reduced to 0.04%. Practical use of fluorine ion adsorption of 0.1%
The following shows that all of these samples are sufficiently usable.

The distribution of the pore size of the synthetic zeolite is
Since there is a problem in that the characteristics of the synthetic zeolite itself are deteriorated by adsorbing the molecules of the fluorocarbon 134a, in order to control the amount of adsorbed fluorine ions to 0.1% or less, the adsorbing capacity of carbon dioxide gas must be reduced to 1%. It has been confirmed that a synthetic zeolite controlled to 0.0% or less should be used.

That is, in a refrigerating apparatus using Freon 134a and a refrigerating machine oil having two or more ester bonds in the molecule of the present invention in a coexistence state, the carbon dioxide adsorption capacity is 25 ° C., the carbon dioxide partial pressure is Synthetic zeolite composed of alkali salts of silicic acid and aluminate controlled at 1.0% or less at 250 mmHg, for example, molecular sieves XH-600 and XH-9 manufactured by Union Showa Co., Ltd. as a desiccant. It was found that practical use was able to remove only water effectively, and had little influence such as powdering due to fluorine ion adsorption and reduction in the strength of beads, and was extremely excellent in practical use.

When the carbon dioxide adsorption capacity is 25 ° C., carbon dioxide partial pressure and 250 mmHg, the lower limit of 1.0% or less is as follows:
It is desirable to be as small as possible. When this is 0%, F ions are not absorbed and only water is selectively absorbed, resulting in an ideal molecular sieve.

[0184]

Since the present invention is configured as described above, it has the following effects.

(1) A compressor that is used in a refrigeration cycle and stores refrigeration oil as a lubricating oil in a closed container and compresses the refrigerant gas. The refrigeration oil used has a viscosity of 40 ° C.
At the time of 2 to 70, more preferably 5 to 32 cSt, 100
When the base oil is an ester oil having two or more ester bonds in a molecule of 1 to 9, more preferably 2 to 6 cSt at a temperature of 0 ° C, and a refrigerating machine oil having a lower critical melting temperature of 0 ° C or lower or -30 ° C or lower, By using the compressor for a medium-temperature refrigeration system such as a dehumidifier as a first target and the compressor for a low-temperature refrigeration system such as a refrigerator as a second target, the refrigerating machine oil and the refrigerant can be used in all temperature ranges of the use environment. Since the two layers are well separated without being separated from each other, the lubricating oil film on the shaft of the compressor, the bearing, and the heat transfer performance of the refrigerant in the heat exchanger are guaranteed, and the performance and reliability of the compressor and the refrigeration system are improved. Can be significantly improved.

(2) Addition of a phosphate ester-based extreme pressure agent having a hydroxyl group in a molecule, other antiwear agents, an acid scavenger, an antioxidant, an antifoaming agent, etc. to the refrigerating machine oil. By using the agent together, the effect of improving the lubricating properties of the sliding portion of the bearing of the refrigerant compressor is improved, and the performance and reliability are improved.

(3) The viscosity of the high pressure vessel type rotary compressor is 2 to 70, preferably 5 to 32 cSt when the viscosity is 40 ° C. The viscosity of the low pressure vessel type reciprocating type compressor is 40 to 70 cSt. At 40 ° C., the refrigerating machine oil of the present invention having two or more ester bonds in each molecule of 2 to 70, more preferably 5 to 15 cSt, is
By using together with 4a, the coefficient of performance indicating the performance of the compressor can be improved, the power consumption of the refrigeration apparatus using the same can be reduced, and the refrigeration capacity can be increased, that is, the so-called performance can be improved. is there.

(4) As a motor insulating material of a refrigerant compressor using a chlorofluorocarbon-based refrigerant represented by chlorofluorocarbon 134a, an insulation-coated winding having a glass transition temperature of 120 ° C. or more and a glass transition temperature of 70 ° C. or more By using the refrigerating machine oil based on the ester oil of the present invention as the refrigerating machine oil, the electrical insulation performance and long-term reliability of the compressor can be remarkably improved.

(5) Silicic acid or alumina having a carbon dioxide absorption capacity of 1.0% or less at 25 ° C. and a carbon dioxide partial pressure of 250 mmHg was placed in a dryer constituting a refrigerating apparatus equipped with the compressor of the present invention. By using synthetic zeolite composed of acid alkali metal salts, water in the refrigeration cycle can be efficiently separated and adsorbed, and problems such as clogging of refrigerant pipes caused by powdering due to deterioration of the desiccant itself and sliding parts of the compressor It is possible to eliminate the abnormal wear phenomenon due to the intrusion of water, and the effect of improving the performance and long-term reliability is great.

(6) The compressor for a refrigeration system according to the present invention constituted as described above has a higher ozone problem in the global environment than a conventional chlorofluorocarbon-based refrigerant gas (for example, chlorofluorocarbon 12). It is possible to reduce the coefficient of destruction (OPP) to zero and the global warming potential (GWP) to 0.3 or less.

[Brief description of the drawings]

FIG. 1 is a two-layer separation temperature diagram for explaining the compatibility between Freon 134a refrigerant and refrigerating machine oil.

FIG. 2 is a characteristic diagram showing the relationship between the amount of water dissolved in various refrigerator oils and the volume resistivity.

FIG. 3 is a graph showing the relationship between the actual viscosity of a refrigerating machine oil and the coefficient of performance during rated operation of a high-pressure container type rotary compressor.

FIG. 4 is a graph showing the relationship between the actual viscosity and the coefficient of performance of a low-pressure container type reciprocating compressor during rated operation.

FIG. 5 is a characteristic showing a relationship between a Falex test having an iron-based friction sliding surface and a high-pressure atmosphere friction test of Freon 134a-dissolved oil.

FIG. 6 is a characteristic diagram showing an amount of wear by a Falex test.

FIG. 7 is a longitudinal sectional view of a main part of the hermetic rotary compressor.

FIG. 8 is a vertical sectional view of a main part of a compression machine part of the rotary compressor.

FIG. 9 is a configuration diagram of a refrigeration cycle of the refrigeration apparatus.

FIG. 10 is a configuration diagram of a refrigeration cycle of the refrigeration apparatus.

[Explanation of symbols]

1 ... case, 2 ... cylinder,
3 ... eccentric part, 4 ... rotating shaft, 5
... Main bearing, 6 ... Sub bearing, 7 ...
Roller, 8… Cylinder groove,
9 ... Spring, 10 ... Vane, 1
3: Refrigeration oil, 17: Shaft hole, 19:
Stator, 19a: winding, 20: rotor, 22: electric motor, 23: compressor unit, 40: compressor, 41: condenser,
42 ... expansion mechanism, 43 ... evaporator,
45 ... Dryer.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C10N 20:02 40:30 (72) Inventor Makoto Tanaka 800 Tomita, Ohira-machi, Shimotsuga-gun, Tochigi Prefecture Tochigi Plant, Hitachi, Ltd. 72) Inventor Yoshiharu Honma 4026 Kuji-cho, Hitachi City, Ibaraki Pref.Hitachi, Ltd.Hitachi Research Laboratories, Ltd. Hirokatsu Kasokabe 502, Kandate-cho, Tsuchiura-shi, Ibaraki Pref., Hitachi, Ltd.Mechanical Research Laboratories Co., Ltd. Hiroshi 502, Kandachi-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. (56) References JP-A-62-191692 (JP) A) JP-A-54-108007 (JP, A) U.S. Pat. No. 4,851,144 (US, A) International Publication 90/12849 (WO, A1) "CFCs: Time of Transcription", American Society of Heating, Refrigerator, and Air-Conditioning Engineers, Inc. p. 211-216 (1989) "Tribologist" (Japan Lubrication Society), Vol. 9, p. 621-626 (1990) (58) Field surveyed (Int. Cl. ⁶ , DB name) C10M 105/38 C09K 5/04 F25B 1/00 395 H02K 3/44 C10N 40:30

Claims (6)

(57) [Claims] (1) Hydrofluorinated carbon (HFC) as a main component
Refrigerant whose critical temperature is 40 ° C. or higher, a hermetic compressor that compresses the refrigerant, a condenser that condenses the refrigerant, a dryer that dries the refrigerant, and an expansion mechanism that expands the refrigerant, An evaporator for evaporating the refrigerant, 2 to 70 cSt when the viscosity is 40 ° C., and 1 when the viscosity is 100 ° C.
９9 cSt, and the volume resistivity is 10 ¹³ Ωcm or more,
At least two ester bonds (-O-CO-) in the molecule
A refrigeration oil months held by ester oils of fatty acid and base oil
The insulating film comprises polyethylene terephthalate, poly
Amidoimide coated polyester, polyphenylene sal
Either Fido or polyetheretherketone 1
Refrigeration equipment which is a kind of insulating film. 2. Hydrofluorinated carbon (HFC) as a main component
Refrigerant whose critical temperature is 40 ° C. or higher, a hermetic compressor that compresses the refrigerant, a condenser that condenses the refrigerant, a dryer that dries the refrigerant, and an expansion mechanism that expands the refrigerant, An evaporator for evaporating the refrigerant, 2 to 70 cSt when the viscosity is 40 ° C., and 1 when the viscosity is 100 ° C.
９9 cSt, and the volume resistivity is 10 ¹³ Ωcm or more,
At least two ester bonds (-O-CO-) in the molecule
50% of water based on fatty acid ester oil
0 ppm or less of refrigerating machine oil, and the insulating film is made of polyethylene terephthalate,
Amidoimide coated polyester, polyphenylene sal
Fido and either the polyetheretherketone 1
Refrigeration equipment which is a kind of insulating film. 3. Hydrofluorinated carbon (HFC) as a main component
A refrigerant having a critical temperature of 40 ° C. or higher and a viscosity of 40 ° C.
Is 5 to 32 cSt, and the volume resistivity is 10 ¹³ Ωc
m or more, the ester bond (-O-CO-) in the molecule is small.
Based on at least two fatty acid ester oils
This is a refrigeration system that is used with refrigerating machine oil enclosed.
This refrigeration system is a closed type high pressure vessel type rotary type pressure compressor for compressing the refrigerant.
A compressor for condensing the refrigerant, a dryer for drying the refrigerant, an expansion mechanism for expanding the refrigerant, and an evaporator for evaporating the refrigerant, wherein the insulating film is polyethylene terephthalate, poly
Amidoimide coated polyester, polyphenylene sal
Either Fido or polyetheretherketone 1
Refrigeration equipment which is a kind of insulating film. 4. Hydrofluorinated carbon (HFC) as a main component
A refrigerant having a critical temperature of 40 ° C. or higher and a viscosity of 40 ° C.
Is 5 to 32 cSt, and the volume resistivity is 10 ¹³ Ωc
m or more, the ester bond (-O-CO-) in the molecule is small.
Based on at least two fatty acid ester oils
With the refrigerating machine oil having a water content of 500 ppm or less
This is a refrigeration apparatus used, and the refrigeration apparatus is a closed type high pressure vessel type rotary type pressure compressor for compressing the refrigerant.
A compressor for condensing the refrigerant, a dryer for drying the refrigerant, an expansion mechanism for expanding the refrigerant, and an evaporator for evaporating the refrigerant, wherein the insulating film is made of polyethylene terephthalate, poly
Amidoimide coated polyester, polyphenylene sal
Either Fido or polyetheretherketone 1
Refrigeration equipment which is a kind of insulating film. 5. A fluorinated carbon (HFC) as a main component.
A refrigerant having a critical temperature of 40 ° C. or higher and a viscosity of 40 ° C.
And the volume resistivity is 10 ¹³ Ωc.
m or more, the ester bond (-O-CO-) in the molecule is small.
Based on at least two fatty acid ester oils
This is a refrigeration system that is used with refrigerating machine oil enclosed.
This refrigerating apparatus is a closed type low pressure vessel type reciprocating pressure type for compressing the refrigerant.
A compressor for condensing the refrigerant, a dryer for drying the refrigerant, an expansion mechanism for expanding the refrigerant, and an evaporator for evaporating the refrigerant, wherein the insulating film is polyethylene terephthalate, poly
Amidoimide coated polyester, polyphenylene sal
Either Fido or polyetheretherketone 1
Refrigeration equipment which is a kind of insulating film. 6. Hydrofluorinated carbon (HFC) as a main component
A refrigerant having a critical temperature of 40 ° C. or higher and a viscosity of 40 ° C.
And the volume resistivity is 10 ¹³ Ωc.
m or more, the ester bond (-O-CO-) in the molecule is small.
Based on at least two fatty acid ester oils
With the refrigerating machine oil having a water content of 500 ppm or less
This is a refrigerating device that is used. The refrigerating device is a closed-type low-pressure container-type reciprocating pressure compressor that compresses the refrigerant.
A compressor for condensing the refrigerant, a dryer for drying the refrigerant, an expansion mechanism for expanding the refrigerant, and an evaporator for evaporating the refrigerant, wherein the insulating film is polyethylene terephthalate, poly
Amidoimide coated polyester, polyphenylene sal
Either Fido or polyetheretherketone 1
Refrigeration equipment which is a kind of insulating film.