JPH0559353A - Compression-type refrigerator and additive therefor - Google Patents

Abstract

PURPOSE:To improve the title refrigerator's durability and reliability by containing in the title refrigerator a non-symmetrical tetrafluoroethane as cooling medium, a polyether oil as refrigerating machine oil, and a hydrochloric acid scavenger to prevent the refrigerating machine oil from damage due to residual chlorine. CONSTITUTION:In the title refrigerator made up of (1) a compressor 1, (2) a condenser 2, (3) a pressure reducing device 4, and (4) an evaporator 5, consisting of a system through their mutual connection, (A) 1,1,1,2-tetrafluoroethane as the main cooling medium, (B) a polyether oil as refrigerating machine oil, and (C) a hydrochloric acid scavenger are contained in this refrigerator to prevent the compressor from damage caused by e.g. spoilage of the refrigerating machine oil due to residual chlorine, thus improving the refrigerator's durability and reliability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression type refrigerating apparatus, and more particularly to a compression type refrigerating apparatus and a filling agent in which a filling agent enclosed in a refrigeration system for a car air conditioner is improved.

[0002]

2. Description of the Related Art Conventionally, a chlorine-based fluorocarbon gas such as dichlorodifluoromethane (hereinafter referred to as Freon 12) is used as a refrigerant for a car air-conditioning system, and a naphthene-based or paraffin-based mineral oil is used as a lubricating oil. Has been. Freon 12 contained chlorine in the molecule and acted as an extreme pressure agent on the sliding surface of the compressor, and thus had excellent self-lubricating properties. Further, mineral oil had a relatively high pressure viscosity index, which is an index of the oil film thickness of the sliding portion, and the oil film was well formed even in the sliding portion to which a high load was applied, and the lubricating property was excellent. Therefore, there were almost no problems such as seizure of the sliding portion of the compressor, abnormal wear, and flaking of the bearing.

However, in recent years, a problem of depletion of the stratospheric ozone layer due to freon gas containing chlorine in the molecule such as freon 12 has been pointed out, and the decrease of this ozone layer has a serious adverse effect on the ecosystem such as an increase in the incidence of skin diseases. It has become clear that For this reason, it was decided at the international conference by the end of this century that the CFC-12 and other CFCs with high ozone depletion potential (hereinafter referred to as CFCs) would be completely abolished, and the reduction of the production of CFCs began in 1989. .. For this reason, there is an urgent need to develop an alternative CFC gas instead of CFC 12 in the refrigerant for car air-conditioning systems, but at present, the boiling point is almost the same as CFC 12 and the pressure-enthalpy characteristics are similar 1,1,1, 2-Tetrafluoroethane (hereinafter referred to as Freon 134a) is the most prominent. This Freon 134a contains neither chlorine nor bromine and does not harm ozone in the stratosphere, so it is expected that it will be widely used not only in car air-conditioning systems but also in other refrigeration cycle devices and sprays. ing.

By the way, this CFC 134a has no compatibility with mineral oil, which is the current refrigerating machine oil, and if it is left as it is, it will hinder lubrication of the sliding parts of the compressor. Therefore, it is necessary to change to a compatible synthetic oil. Is forced. Among synthetic oils, polyether-based oils (particularly polyalkylene glycol-based oils, hereinafter referred to as PAG oils) with the same two-layer separation temperature range as the current ones are the most powerful in car air-conditioning systems, and are versatile in the industry. It agrees in the direction of adopting excellent PAG oil.

[0005]

However, this PAG
Oil has very poor stability against chlorine, and if chlorine is mixed in, the lubricity of oil deteriorates. Further, since copper is melted, a so-called copper plating phenomenon occurs on the surface of the iron-based component, and when this is a sliding surface, sliding characteristics are deteriorated. It has been clarified that these causes cause various problems in the compressor, such as seizure of sliding parts, abnormal wear, corrosion, flaking of bearings, and the like. Also, since PAG oil is originally highly hygroscopic, there is a problem that when a high temperature and high pressure are generated in a state of containing a large amount of water, a certain type of PAG oil is hydrolyzed to generate a strongly corrosive organic acid. It accelerates this further and causes great damage to the compressor.

However, the possibility that chlorine may be mixed in the refrigeration cycle of a car air conditioner using the Freon 134a is extremely high at present. One of them is a case where a chlorine-based cleaning agent is used for cleaning the parts. Not only when the drying after cleaning is insufficient, but also when it is dried sufficiently, chlorine remains in the form of chloride on the surface of the component. Alternatively, it melts into the refrigerant. At present, Freon 113, which is one of the specified Freons, is widely used as a chlorine-based cleaning agent. Like CFC12, CFC113 is destined to be abolished at the end of this century, but unlike CFC12, its replacement is delayed.

Therefore, some manufacturers temporarily switch from cleaning with chlorofluorocarbon to cleaning with an organic solvent, but since this organic solvent also requires a high degreasing ability, it is expected that chlorine-based trichloroethane will be used as well, and residual chlorine will be used. Is likely to occur. In addition to this, for example, when a chlorine-based flux is used during the welding work of the condenser or the evaporator, when the CFC 12 is erroneously enclosed during the cycle, or when the parts are directly touched with hands, etc. Also chlorine can be mixed in during the cycle. Therefore, the present invention has an object to provide a compression type refrigerating apparatus that uses CFC 134a as a refrigerant and has excellent durability and high reliability, and also to provide a filler to be enclosed in the refrigerating apparatus. is there.

[0008]

In order to achieve the above object, the present invention provides a compression refrigeration system having a compressor, a condenser, a pressure reducing device and an evaporator, which are connected to form a cycle. , As the main refrigerant in the refrigeration system
A compression type refrigerating apparatus is characterized in that 1,1,2-tetrafluoroethane, polyether oil as a refrigerating machine oil, and a hydrochloric acid scavenger are enclosed. Further, in the present invention, a compression composed of 1,1,1,2-tetrafluoroethane as a refrigerant, polyether oil as a refrigerating machine oil, and 0.01 to 2.00% by weight of a hydrochloric acid scavenger with respect to the refrigerant. It is used as a filler for a refrigerator. Further, in the above, as the hydrochloric acid scavenger, it is preferable to use one or more selected from an epoxy compound such as phenylglycidyl ether, a phosphite ester such as tricresyl phosphate, and an organic tin compound such as triphenyltin hydroxide. ..

[0009]

With the above-mentioned compression refrigerating apparatus, when Freon 134a is used as the refrigerant and polyether oil is used as the refrigerating machine oil, even if chlorine is mixed in the cycle, the hydrochloric acid scavenger immediately reacts with chlorine. To capture P
AG oil does not deteriorate and does not impair lubricity.
Therefore, seizure of the sliding portion, abnormal wear, corrosion, flaking of the bearing, etc. do not occur in the compressor. Also,
In iron-based metals, a multi-layered compound film formed on the metal surface by a chemisorption effect is effective in suppressing hydrogen absorption of the metal. Therefore, the occurrence of flaking damage due to hydrogen embrittlement of the bearing, which is a problem when some PAG oil is used, can be suppressed by adding this hydrochloric acid scavenger.

Further, by using the above-mentioned refrigerating apparatus filler, it is possible to prevent forgetting to enclose the hydrochloric acid scavenger and to save the trouble of encapsulating the hydrochloric acid scavenger. When replenishing, the hydrochloric acid scavenger is also replenished at the same time, so that the hydrochloric acid scavenger in the refrigeration cycle does not run short. As described above, the refrigeration cycle apparatus can ensure high durability and reliability, and the market serviceability is improved.

[0011]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to these. Example 1 A case where the present invention is applied to a car air conditioner system will be described with reference to FIG. In FIG. 1, a compressor 1, a condenser 2, a refrigerant reservoir 3, a pressure reducing device 4, an evaporator 5 and the like are connected in an annular shape,
It constitutes a cycle circuit. Further, Freon 134a is used as a refrigerant inside the cycle, and PAG is used as a refrigerating machine oil.
It contains oil. Of course, a hydrochloric acid scavenger is also enclosed. The evaporator 5 is installed inside the vehicle compartment, and the condenser 2 is installed outside the vehicle interior.

In such a refrigeration cycle apparatus, the refrigerant in the cycle circulates in the direction of the arrow shown in FIG.
That is, the refrigerant that has been compressed by the compressor 1 and has become high temperature and high pressure is sent out to the condenser 2 outside the vehicle compartment and releases heat to the air to be cooled. The cooled and liquefied refrigerant passes through the refrigerant reservoir 3 and is expanded by the decompression device 4 to be gasified again. At this time,
The temperature of the refrigerant decreases as much as the heat radiated by the condenser 2.
The low-temperature refrigerant is sent to the evaporator 5 in the vehicle compartment and removes heat from the surroundings to cool the air in the vehicle compartment. on the other hand,
The refrigerant that has taken the heat is sent to the compressor 1 again and compressed. This cycle is repeated.

Example 2 A shielded tube test was conducted to confirm the stability of PAG oil used as a refrigerating machine oil against chlorine. Two types of samples were prepared. Sample No. Sample No. 1 is PAG oil only. Reference numeral 2 is a PAG oil containing 1% of Freon 113 containing chlorine in its molecule. These two samples are heated to 15
Leave it in a constant temperature bath at 0 ° C for a certain period of time to AST the degree of oil deterioration.
It was judged by M chromaticity. The results are shown in Table 1.

[Table 1]

Sample 1 has a chromaticity of L1.0 even after being left for 20 days.
No sign of deterioration was seen, whereas No. Two
After 3 days, the chromaticity was L8.0 and deteriorated to the worst state.
For this reason, it is necessary to avoid mixing of chlorine into the cycle as much as possible, and even if it is mixed, it is necessary to immediately capture it and not deteriorate the PAG oil. next,
In order to examine the effectiveness of the chlorine scavenger, a durability test was conducted using an actual refrigeration cycle device using a hydrochloric acid scavenger. The test conditions are as follows.

(1) Compressor: Swash plate type compressor (total displacement 170 cc) (2) Rotation speed: 5500 min ⁻¹ (3) Discharge side pressure: 1.86 MPa (4) Suction side pressure: 0.201 MPa (5 ) Refrigerator oil: PAG oil (150 cc enclosed) (6) Refrigerant: Freon 134a (1 kg enclosed) (7) Chlorine scavenger: No3 ... 0.
01 wt% encapsulation No4 ・ ・ ・ 〃 0.10 wt% encapsulation No5 ・ ・ ・ 〃 1.00 wt% encapsulation All use phenyl glycidyl ether, which is a type of epoxy compound (8) Cleaning conditions: compressor and refrigeration cycle Chlorine-based Freon 113 was used for all the inside, and it was sufficiently dried. However, in Nos. 2 to 5, after drying, CFC 113 was added at 1% by weight with respect to the amount of the enclosed refrigerant.

The test results are shown in Table 2.

[Table 2]

No. In No. 1, 24.3 hours after the start of the test, the discharge valve of the compressor cracked and became NG. Residual chlorine amount is 1
It was as high as 21 ppm, and it was proved that chlorine could not be removed completely even when dried. No. 2 is 11.5 after starting the test
The result was an even worse result of the compressor piston breaking over time, resulting in a failure. As a result of disassembly and investigation, it was found that the inside of the compressor was badly corroded. The total acid number, which indicates the degree of oil deterioration, is No. Compared with the case of 1, it was abnormally high, and it was confirmed that the deterioration of the oil proceeded because the amount of residual chlorine increased. No. Nos. 3, 4 and 5 are the results of tests conducted by adding a hydrochloric acid scavenger. All completed the prescribed test time without any abnormality. All residual chlorine is 10
It was below ppm and the total acid value was also low, demonstrating that the hydrochloric acid scavenger is effective. It was also found that the residual rate of the hydrochloric acid scavenger after the test was 78 to 98% by weight, which was a sufficient value. From this, the hydrochloric acid scavenger should be at least 0.01% by weight, and there is no problem even if it is added up to 2.0% by weight.

Example 3 A shielded tube test was conducted to confirm the effect of other hydrochloric acid scavengers on a desk. The test method is as follows. That is, prepare 4 glass tubes in which 1 ml of hydrochloric acid was added to 5 ml of PAG.
o. 6 is phenyl glycidyl ether, and sample No. 7
Is tricresyl phosphate, and sample No. Triphenyltin hydroxide, which is a type of organic tin compound, was added to 8 and sealed, and then the mixture was allowed to stand in a thermostat at 120 ° C. Table 3 shows the test results. The degree of oil deterioration was judged by ASTM degree.

[Table 3]

Sample No. 9, that is, the sample in which the hydrochloric acid scavenger was not added deteriorated to the worst state in 0.5 hours. However, sample No. The degree of deterioration was 6, 7 and 8 and the effect was confirmed. However, phenylglycidyl ether or triphenyltin hydroxide has a greater hydrochloric acid scavenging effect than tricresyl phosphate. As a method of enclosing these hydrochloric acid scavengers in the refrigeration cycle in the apparatus, it is preferable to mix the hydrochloric acid scavenger with the refrigerant in advance and enclose the hydrochloric acid scavenger together when the refrigerant is filled. According to this method, it is possible to avoid forgetting to add the hydrochloric acid scavenger. The hydrochloric acid scavenger is Freon 1
It dissolves in 34a.

In addition, since an organic material such as a flexible hose and an O-ring is used in the car air conditioner system, the refrigerant molecule leaks because it is smaller than this organic material molecule when used for many years. Therefore, it is necessary to refill the refrigerant every certain period of time. By the way, when a hydrochloric acid scavenger is used, the hydrochloric acid scavenger is soluble in freezing, and therefore leaks together with the refrigerant. However, since only the refrigerant is filled in the conventional refrigerant filling service can, the hydrochloric acid scavenger cannot be replenished. However, as in the case of the present invention, if a filler for a refrigerating apparatus containing a hydrochloric acid scavenger is used, this problem can be solved and there is no shortage of the hydrochloric acid scavenger in the refrigeration cycle apparatus.

[0021]

As described above, according to the present invention, the PAG oil is not deteriorated by enclosing the hydrochloric acid scavenger in the cycle of the compression refrigerating apparatus using the Freon 134a and the PAG oil. In the compressor, no trouble such as seizure on the sliding portion or abnormal wear occurs. Therefore, it is possible to provide a refrigerating device having excellent durability and reliability. Further, by using a chlorine scavenger-containing filler for a refrigeration system, it is possible to avoid forgetting to add the hydrochloric acid scavenger, and the hydrochloric acid scavenger can be replenished when refilling the refrigerant. This makes it possible to improve market serviceability.

[Brief description of drawings]

FIG. 1 is a refrigeration circuit diagram of a car air conditioner system using the present invention.

[Explanation of symbols]

1 ... Compressor, 2 ... Condenser, 3 ... Refrigerant reservoir, 4 ... Decompression device, 5 ... Evaporator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Ueda 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi, Ltd. (72) Inventor Hideki Machimura 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi, Ltd. Within

Claims (5)

[Claims] 1. A compression type refrigerating apparatus having a compressor, a condenser, a decompressor, and an evaporator, which are connected to each other to form a cycle.
A compression type refrigerating apparatus comprising 1,1,2-tetrafluoroethane, a polyether oil as a refrigerating machine oil, and a hydrochloric acid scavenger. 2. The compression type refrigerating apparatus according to claim 1, wherein the enclosed amount of the hydrochloric acid scavenger is 0.01 to 2.0% by weight based on the enclosed refrigerant amount. 3. The compression type refrigerating apparatus according to claim 1, wherein the hydrochloric acid scavenger contains at least one selected from an epoxy compound, a phosphite ester, and an organic tin compound. 4. A compression system comprising 1,1,1,2-tetrafluoroethane as a refrigerant, polyether oil as a refrigerating machine oil, and 0.01 to 2.0% by weight of a hydrochloric acid scavenger with respect to the refrigerant. Filler for refrigerator. 5. The filler for a compression refrigerator according to claim 4, wherein the hydrochloric acid scavenger contains at least one selected from an epoxy compound, a phosphite ester, and an organic tin compound.