WO1994012594A1

WO1994012594A1 - Ammonia refrigerating unit, working fluid composition to be used in said unit, and lubrication of ammonia compressor

Info

Publication number: WO1994012594A1
Application number: PCT/JP1992/001551
Authority: WO
Inventors: Keisuke Kasahara; Kuniaki Kawamura; Takashi Kaiwai; Hisashi Yano
Original assignee: Kyodo Oil Technical Research Center Co., Ltd.; Maekawa Mfg. Co., Ltd
Priority date: 1992-11-27
Filing date: 1992-11-27
Publication date: 1994-06-09

Abstract

A refrigerator working fluid composition comprising an ammonia refrigerant and a lubricating oil which has a remarkably good compatibility therewith, and a method of lubricating a refrigerating unit suitable when the above composition is used. The composition comprises a mixture of ammonia with one or more polyether compounds represented by the general formula (I): R1-[-O-(PO)m-(EO)n-R2]x wherein R1 represents C1-C6 hydrocarbon group; R2 represents C1-C6 alkyl; PO represents oxypropylene; EO represents oxyethylene; x represents an integer of 1 to 40; m represents a positive integer; and n represents 0 or a positive integer. The refrigerating unit comprises circulating the above composition in a circulatory cycle and constituting a refrigeration or heat pump cycle. The method of lubricating an ammonia refrigerant compressor comprises the use of a lubricating oil comprising one or more ether compounds of general formula (I).

Description

Thread in

Ammonia refrigeration system, lubrication of the working fluid composition used in the refrigeration apparatus and Anmo Nia compressor ^_

"Technical field"

The present invention relates to a refrigeration and heat pump apparatus using a refrigerant containing ammonia as a main component, a working fluid composition obtained by mixing a refrigerant and lubricating oil used in the refrigeration apparatus, and a method for lubricating an ammonia compressor.

"Background technology"

Freon, which has been widely used as a refrigerant in refrigeration and heat pump devices (hereinafter referred to as refrigeration devices), is released into the atmosphere and accumulates. This has resulted in the destruction of the layers of the Earth, which serve to protect the Earth from the sun's intense UV light, thereby limiting its use. Therefore, in recent years, ammonia has been reviewed as an alternative refrigerant.

In other words, ammonia refrigerant has no danger of destruction of the global environment like a humid refrigerant, and its refrigeration effect is not less than that of chlorofluorocarbon, and it is also inexpensive. However, amplifiers have drawbacks such as toxicity, flammability, insolubility in mineral oil used as compressor lubricating oil, and higher discharge temperature from compressor. The refrigeration system is configured so that no problems occur due to these shortcomings.

Explaining the specific structure based on Fig. 6, 50 is the evaporator side for example-10 t, and the condenser side is a single-stage compression type for obtaining heat of around +35 ° C. The configuration of the direct expansion refrigeration system will be described mainly with regard to its operation.The oil-mixed ammonia refrigerant compressed by the refrigerant compressor 51 is separated into oil by the oil separator 52, and then separated by the condenser 53. It is condensed and liquefied in the condenser 53 by heat exchange with the cooling water 64 (acquired heat: 3δX: before and after).

Then, the liquor separated at the time of the condensation is further separated by the oil reservoir 55 provided at the bottom of the high-pressure receiver 54, and the ammonia refrigerant is decompressed and vaporized by the expansion valve 56. After heat exchange with the blast load supplied by fan 58 (obtained heat: — i O "C), it is further sucked into the intake side of compressor 51 through ammonia liquid oil separator 59. Repeat the frozen cycle.

The oil collected at the bottom of the oil separator 52, the oil sump 55 at the bottom of the receiver, and the bottom of the evaporator 57 are all oil drain valves 60a, 60b, 6ϋc, 60 Then, the liquid accumulates in the oil receiver 61 via the d and is returned into the compressor 52 again from the oil spraying section 52 of the compressor 51 to clean, seal, and cool the movable parts. One.

It is well known that the refrigerating device i 50 can be applied as a heat pump device by extracting heat from the condenser 53 side, and therefore these are collectively referred to as a refrigerating device. „

The lubricating oil generally uses mineral lubricating oils such as paraffinic and naphthenic oils. Since these lubricating oils do not dissolve in ammonia, an oil separator is installed on the discharge side of the compressor. To separate the ammonia gas and the lubricating oil discharged from the compressor, and even if the separator is provided, the mist-shaped lubricating oil cannot be completely removed, and the discharge of the compressor The lubricating oil slightly dissolves or mixes in the ammonia due to the high temperature on the side, and enters the refrigeration cycle along with the ammonia, and then in the cycle. Since the lubricating oil that has entered is insoluble in ammonia and has a high specific gravity, it tends to accumulate in the piping path of the cycle. Therefore, the bottom of the high-pressure receiver 54 and the evaporator 57 At the lower inlet side of the An oil separator 59 must also be provided on the intake side of the machine 51, and these separated oils must be recovered by the oil receiver 61 and then returned to the compressor again. Is extremely complicated.

In addition, the fact that the lubricating oil is insoluble in the refrigerant as described above means that the oil adheres to the wall of the heat exchange coil in the condenser 53 and the evaporator 57 and the heat transfer efficiency is reduced. In particular, in a low-temperature evaporator, the viscosity of Shant becomes high, the oil drainage fluidity is reduced, and the heat transfer efficiency is further reduced.

Therefore, it is necessary to separate the insoluble oil on the artificial side of the evaporator 57 as much as possible ^ For this purpose, introduce the decompressed refrigerant after passing through the expansion valve 56 from above the evaporator 57. In this case, even if a special separator is used, it cannot be prevented from entering the evaporator 57 due to a difference in specific gravity. It is inevitable to adopt a so-called bottom feed structure with a section.

However, if the bottom feed structure is adopted, it is inevitable to take a so-called full structure, in which the refrigerant can be discharged from the upper end of the evaporator against the gravity corresponding to the height of the evaporator 57. As a result, a large amount of refrigerant is required in the refrigeration cycle.

The ammonia i-system mentioned earlier has a use limit of around 20 '. In recent years, the intensity of the amusement process has dropped significantly. The required cooling temperature is lower than that of rii, which prevents leaching of j, ik and other qualities, and most of the following, especially in high-priced foods such as tuna. In addition, the cryopreservation temperature is significantly lower from-50 ° C to 160 ° C.

Such a freezing temperature cannot be obtained with the single-stage compressor as described above. Usually, a two-stage compressor is used. However, as in the conventional technique, the evaporator temperature is −40. When cooled below °, the fluidity of the lubricating oil is greatly reduced, as shown in Table 3 below, and the evaporator becomes clogged.

To remedy this drawback, a cryogenic ammonia two-stage compression liquid pump recirculation system as shown in Fig. 7 has been proposed.

The structure of the condensate discharged from the high-pressure receiver 54 to the liquid pipe 66 will be briefly described with a focus on the difference between the above-mentioned conventional technologies.

The inside of the liquid pipe 66 is cooled, while the terminal side of the liquid pipe 66 is introduced into a supercooling pipe 69 in the intercooler 68, and is cooled to about 110 ° C in the supercooling pipe 69. After cooling, it is decompressed and vaporized by the expansion valve 74 and introduced into the low-pressure receiver 70.

As a result, the liquid coolant cooled to 140 to 150 or less is stored in the liquid receiver 70. ·

This refrigerant liquid is supplied to the evaporator via the liquid pump 71 and the flow control valve 72.

7 3, heat exchange with the blast load supplied from the fan 7 4 in the evaporator 7 3 (Example of acquired heat: The refrigerant evaporated by 14 (TC) is re-heated to the low-pressure receiver 7). It is introduced into 0 and cooled and liquefied.

On the other hand, the vaporized refrigerant in the low-pressure receiver 70 is sucked into the low-stage compressor 75, is compressed, and the compressed gas is cooled in the intermediate cooler 68, and is cooled in the intermediate cooler 68. The condensed refrigerant from the liquid pipe 66 is introduced into the heat exchange supercooling pipe 69 to be supercooled to about 110 ° C, and is decompressed and vaporized by the expansion valve 74 so as to be low-pressure receiver. Introduce within 70.

Then, the vaporized refrigerant in the intercooler 68 is compressed by the high-stage compressor 51 ′, and the cycle is repeated.

Oil reservoirs 55, 68a, and 7ϋa are also provided at the bottoms of the high-pressure receiver 54, the intercooler 68, and the low-pressure receiver 70, respectively. After the oil is collected by the oil receiver 61, it is returned to the Shantou injection parts 51a, 75a on the high-pressure compressors 5, 75 side. In the figure, the liquid floating valve is

However, even in this conventional technique, not only the fundamental disadvantages such as the complicated configuration of the recovery of the shanks and the reduction of the heat transfer efficiency are not solved, but also the low-pressure receiver 70 side particularly has the following problems. 0 X: Coolant liquid stored in the reservoir is stored, and the lubricating oil stored in the oil reservoir is also cooled back and forth between 140 and 150, greatly reducing fluidity. However, in order to perform the oil drainage, the temperature of the oil must be temporarily increased, and as a result, the continuous operation of the cooling cycle is required. A hindrance occurs, and maintenance is required to stop the cycle and recover oil every time the oil is stored at a predetermined ffi.

On the other hand, many closed-type compressors are used in refrigeration and air-conditioning units for home use, and since then, dichlorodifluoromethane (R12) and chlorodifluoromethane (R) have been used. CFC and HCFC refrigerants such as 2 2) will be used, and HFCs that do not contain chlorine in the future, such as —, 1, 1, 2—Tetrafluca (R134a) Fluorine gas is expensive, while ammonia is cheaper and has a better heat transfer coefficient than the above-mentioned fluorocarbons, and has an allowable temperature (critical temperature) and pressure as a refrigerant. The use of ammonia is advantageous because of its high cost, the expansion valve is not clogged because it dissolves in water, and the latent heat of vaporization is large and the refrigeration effect is large. Ammonia is corrosive to copper-based materials Therefore, it cannot be used at present because the recovery and circulation of oil alone is extremely difficult due to the insolubility of ammonia and lubricating oil.

However, if a lubricating oil having excellent solubility with ammonia and not deteriorating in quality even after long-term use is developed, most of the above problems can be solved.

Lubricating oils having such compatibility have already been proposed in the field of fluorocarbons. For example, polyhydric alcohol esters and polyoxyalkylene glycol compounds are known. There is no example for refrigerant. Ammonia is highly reactive: If any hydrolysis of the ester occurs, it will form an acid amide, causing sludge precipitation, and poor solubility with ammonia. However, it is difficult to use these lubricants in combination with ammonia refrigerant.

In view of such technical problems, the wood invention is a working fluid composition for a refrigerator, which is obtained by mixing a lubricating oil having excellent compatibility with an ammonia refrigerant and also having excellent lubricity and stability and an ammonia refrigerant. (Hereinafter simply referred to as working fluid composition).

It is another object of the present invention to provide a refrigerating apparatus it suitable for using the working fluid composition.

Another object of the present invention is to use the above-described stimulating fluid composition and further advance the elimination of the above-mentioned disadvantages of ammonia, and a refrigeration apparatus incorporated in the equipment. ^ Provides a method for contracting the machine. "Disclosure of the invention"

In order to obtain a working fluid composition of the working fluid, the inventors of the present invention have prepared a polyoxyalkylene glycol having a specific structure, in which all terminal 〇H groups are substituted with 〇R groups (hereinafter simply referred to as poly It has been found that they have excellent compatibility with ammonia and exhibit excellent lubricity and stability even in the presence of ammonia, and have completed the present invention.

That is, the first invention is a working fluid composition comprising a mixture of ammonia and a lubricating oil for an ammonia compressor using a compound of the following general formula (I) as a base oil of a lubricating oil.

R-C-0- (P0) _m- (E0) _n -R ₂ ] _x (I)

(In the general formula (I), R i is a hydrocarbon group having 1 to 6 carbon atoms, R ₂ is an alkyl group having 16 carbon atoms, P 0 is oxypropylene, and E 0 is oxyethylene. The group, X is an integer from 1 to 4, m is a positive integer, and η is () or still a positive integer.)

Further, the second invention is characterized in that an ammonia refrigerant and a lubricating oil that can be dissolved in the ammonia refrigerant and do not separate into two layers even at the evaporating temperature of the refrigerant are filled in the refrigeration system, The refrigeration or heat pump cycle is made by filling lubricating oil in an ammonia refrigerant at 2% by weight or more.

In this case, the ammonia refrigerant and the lubricating oil may be mixed in advance to form a working fluid composition, or they may be separately charged into a refrigeration or heat pump cycle, respectively. A working fluid composition may be comprised.

The lubricating oil of the present invention is not limited to the first invention alone, and may be any lubricating oil that can be easily dissolved in ammonia refrigerant and does not separate into two layers even at the evaporation temperature of the refrigerant.

In an ammonia refrigerating apparatus using a sealed ammonia compressor in which an electric motor is directly connected to the compressor,

A stator core around a rotor on the motor side is surrounded by a hermetic diaphragm, and is surrounded by a predetermined gap with the rotor, and the rotor core is provided between the rotor inner space and a compressor. By providing a conducting portion through which the composition can pass, it is possible to provide a more preferable ammonia refrigeration apparatus.

Further, a lubricating oil using the compound of the general formula (I) as an oil is not necessarily used only as a working fluid to be compatible with ammonia, but is used as a lubricating oil for an ammonia compressor. You can also. This is the third invention, Next, the respective inventions will be described in detail.

First, the compound represented by the above general formula (I) is a polyether of a desired propylene oxide or a random or block copolymer of propylene and ethylene glycol. . The compound of the formula (I) is collectively referred to as a so-called polyoxyalkylene glycol-based compound, and many examples of using the compound as a lubricating oil for a refrigerator using HCFC or CC as a refrigerant are known. . For example teeth; S 4 9 4 8 5 2 5 (corresponding Japanese application: Publication 2 - 4 3 2 9 0, the 2 - 8 4 4 9丄), the - general formula R _t - (0 R ₂₎ a — Polyoxyalkylene glycol monoether having a structure of 0 H (R is an alkyl group having 1 to 18 carbon atoms, R ₂ is an alkylene group of C 1 to C 4), and S 4 2 6 7 0 6 4 (corresponding Japanese application: public announcement 6 1 — 5 2 8 8 0) and US 4 2 4 8 7 2 6 (corresponding Japanese application: public publication

5 7-4 2 1 1 9), [〇 1 (R ₂ 〇) m-R ₃ ] n and R _t — 0 — (R _≥ 〇) m — R ₃ Polyglycol (R ₃ is hydrogen, hydrocarbon group, aryl group) US 4 7 5 5 3 1 6 (corresponding Japanese application: Publication 2)

-5202385), a polyalkyleneglycol-luca having at least two hydroxyl groups, S'S48551144 (corresponding Japanese application: Published Japanese Patent Publication No.

Combining EO and P〇 with US Pat. No. 4,971,717,2 (corresponding Japanese application: Publication 3-103497) In addition, a polyalkylene glycol having one hydroxyl group is introduced. It is stated that all of these are excellent in solubility with HFC and HCFC.

The applicant of the present application has proposed, as a lubricant for a compressor for HFC, a polyoxyalkylene grease having a structure of R i—〇 one (AO) n —t I, R, -0— (AO) _n —R _2. Patents on coal monoether and polyoxyalkylene glycol polyester, published in Japan 1-259,093, 112

— 259 995, and 3 — 109 492.

However, these known documents do not describe any relationship with ammonia. Since H-C and HCFC are inactive, while ammonia has high reactivity and completely different solubility, it is necessary to complete the present invention to be used in the presence of ammonia refrigerant. Information is helpful

Regarding the ammonia refrigerant, "Synthelic Lubricant and Their Rei ΓΓ igera 1.ion Λ ρρ1 i cations", Lubrica Lion Ens'inenerng, VoI.46, o. 4, Page 239-249, the high viscosity index poly US Pat. No. 4,447,097 describes that _alpha -refined and isonoflavinous mineral oils are useful, esters form sludge, and are hard-working for acute use. 40 19 (corresponding Japanese application: Published Japanese Patent Application Publication No. 58-1-1ϋ630) describes improvement of a refrigeration system for ammonia refrigerant. However, none of these known documents describes the relationship between the ammonia refrigerant and the polyether compound.

The polyether represented by the general formula (I) has a viscosity required as a lubricating oil. Depending on the application, the polyether is 22-68 cSt at 100 ° C and 5-100 C at 100 ° C. It has a viscosity of 15 cSt. The factor that greatly affects the viscosity is the molecular weight, and the molecular weight is preferably from 300 to 180 to set the above viscosity.

Polyethers of the general formula (I) is a polyether which all end by R t and R ₂ are Kusarisa sealed. Here, R t is a hydrocarbon group having 1 to 6 carbon atoms. Here, the hydrocarbon group means the following (i) or (ii). That is, R i is (i) a C 1 -C 6 chain derived from a saturated linear or branched C 1 -C 6 chain hydrocarbon group, specifically, a C 1 -C 6 aliphatic monohydric alcohol. 6, alkyl, i.e., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isopentyl, hexyl, or isohexyl However, particularly from the viewpoint of lowering the two-layer separation temperature, an alkyl group having 14 to 14 carbon atoms, more preferably an alkyl group having 1 to 2 carbon atoms, ie, a methyl or ethyl group, or (ii) 2 — 4 Saturated aliphatic polyhydric alcohols, specifically ethylene glycol, propylene glycol, diethyl glycol, 1,3-propanediol, 1,2-butanediol, 1,6-hexanedioxide Le, 2 — etil — 1, 3 Hydrocarbon residues derived from hexanediol, neopentylglycol, trimethyl-l-propane, trimethyll-l-pronone, trimethylol-butane, pentaerythritol, In other words, it means a hydrocarbon S in which all of the hydrogens of the 2 to 4 hydroxyl groups possessed by these 2 to 4 valent alcohols are substituted. Therefore, X in the general formula (I) is an integer of 114 corresponding to the valence of the alcohol that becomes δ of the hydrocarbon の of _Rx . In order to particularly enhance the solubility with ammonia, X is 1 and R is preferably methyl or ethyl ,,,

R ₂ is an alkyl group having 1 to 6 carbon atoms. With an alkyl group of 7 or more, the temperature of two-way separation from ammonia is too high to achieve the object of the present invention. Has 1 to 4 carbon atoms, and 1 to 2 carbon atoms. The compatibility, that is, the bilayer separation temperature is further reduced, so that it is preferable. When X is 2—4, R ₂ takes 2 to 4 alkyl groups, which may be the same or different, and still maintain a favorable compatibility with R 2 ₂ is 1 to 4, especially 1 to 2 is preferred.

Generally because in NiTeru separation temperature increases the tendency of ammonia the number of carbon atoms of R _t and R ₂ is rather large, to maintain 1¾ good compatibility, the total number of carbon atoms in R and R _.XI 1 0 or less, good Ri preferred to rather than 6, further preferable to rather 4 or less, the ,, Note R _t or R ₂ is most preferred to rather 2 - If one also rather has both the hydrogen The reaction with ammonia produces sludge, failing to achieve the objective of the invention.

When synthesizing the compound of the general formula (I), if the hydroxyl group of the 1- to 4-valent alcohol remains partially unreacted, the obtained polyol can be used for a long period of time. Not good because it creates sludge. Therefore, the hydroxyl group of the alcohol should not remain as much as possible. Specifically, the hydroxyl value of the compound of the general formula (I) is 10 mgK〇HZg or less, and furthermore, 5 mgK0H / g or less is preferred.

As described above, the viscosity of a lubricating oil containing a polyester compound represented by the general formula (I) as a base oil is 22-68 cS1: at 40 ° C and 5 at 100 ° C. — 16 cSt. This viscosity is necessary to maintain good lubricity in the presence of ammonia. Further, in order to maintain good solubility with ammonia, the average molecular weight is preferably from 300 to 180, and if the average molecular weight is less than 300, the viscosity is low and the lubrication is good. However, if it exceeds】, 800, the compatibility with ammonia deteriorates. The control of the average molecular weight is achieved by appropriately selecting the polymerization degrees m and n in addition to R ₁ , R ₂ .

Furthermore, the relative ratio of the degree of polymerization (m) of the oxypropylene group and the degree of polymerization (n.) Of the oxyethylene group, that is, the value of m (m + n), determines the lubricity, low-temperature fluidity and ammonia. Important for compatibility with In other words, if n is too large with respect to m, the low-temperature pour point will increase and the compatibility with ammonia will decrease. From this viewpoint, the value of niZ (m + n) is preferably 0.5 or more. The compound of the general formula (I) in which n is 0 has good compatibility with ammonia and good lubricity. Polyether with oxypropylene (P 0) and oxyethylene (E 〇), which is higher than 0.5 in rn Z (rn + n), is more preferable than the single H-merification of (P 〇). , While maintaining good compatibility, the compatibility becomes negative. Xylene alone or more xylene than propylene

The polyether that is IB-mixed in (4) has a high pour point and a high hygroscopicity, and requires attention. From the viewpoint of compatibility with ammonia, lubricity, and fluidity, the preferable range of the value of m / (m + n) is 0.5 to 1.0, more preferably 0.5 to 0.9. , And more preferably 0.7 — 0.9.

In addition, the copolymer of oxyethylene and oxypropylene is not limited to the block copolymer, but it is not limited to the block copolymer in general formula (I). But it can be an alternating copolymer. The binding order of old Kishiechiren portion and Okishipuro Pile emission portion in pro click copolymerization, even Dochi Ragasaki may bind other words R _t and Dochi et al. A polyether compound such as oxybutylene, which is a compound of xylylene having 4 or more carbon atoms, is not preferred because it is incompatible with ammonia.

Next, the setting of the compatibility with the ammonia refrigerant, that is, the two-layer separation temperature, is determined based on the intended use. For example, a cryogenic refrigerator requires lubricating oil having a two-layer separation temperature of 150 ° C. or less, a conventional refrigerator of 13 ° C. or less is sufficient, and an air conditioner of —20 C The following lubricating oils may be used. Particularly when a compound having a low bilayer separation temperature is required, R 1 is most preferably a methyl group.

The compounds of the general formula (I) can be used alone or in combination of two or more. For example, a polyoxypropylene dimethyl ether having a molecular weight of 800-1 OO 0 and a polyoxyethylene propylene diethylene ester having a molecular weight of 1200-130 are used alone or in a ratio of 10: 90-0: 10 (weight). ), And a viscosity at 40 ° C of 32 to 50 cSt is exemplified.

The polyether compound of the general formula (I) is obtained by starting from an i-tetravalent alcohol having 1 to 6 carbon atoms or an alkali metal salt thereof, and starting from an alkylene alkyd having 2 to 3 carbon atoms. After the IS compound, an ether compound having one end of the chain-like polyalkylene group bonded to the hydrocarbon group of the raw material alcohol by an ether bond and the other end of which is hydroxyl is obtained. It can be obtained by etherifying hydroxyl.

In order to etherify the hydroxyl group of an ether compound having a hydroxyl-group at the terminal, an alkali metal salt of a lower alcohol such as an alkali metal salt such as metal sodium is used. To obtain an alkali metal salt of the ether compound, and then react the alkyl halide with an alkyl halide having 1 to 6 carbon atoms. There is a method of reacting a genide, or a method of converting hydroxyl of an ether compound into a halide and then reacting with a monohydric alcohol having 116 carbon atoms.

Therefore, polyoxyalkylene glycol having hydroxyl groups at both ends can be used as a starting material without necessarily using alcohol as a starting material. In any case, the polyether compound of the general formula (I) may be produced by an appropriate known method.

The refrigerating machine oil of the wood invention stably dissolves in a very wide mixing ratio with ammonia. Also exhibits good lubricity in the presence of ammonia.

Further, as will be described later, by adding an additive such as a diamond cluster, the mixing ratio of the lubricating oil can be further reduced while the lubricating property is secured.

Therefore, the lubricating oil for refrigerators of the present invention is based on the compound represented by the general formula (I), and the composition of the working fluid circulating through the refrigeration and heat pump cycle of the present invention. It is preferable that the mixing ratio of ammonia and the polyether compound of the general formula (I) is 98: 2 (weight ratio) or more.

The lubricating oil and the working fluid composition for refrigerators of the present invention may contain various additives such as a load-bearing agent such as triglyceryl phosphate, an amine-based antioxidant, and a benzotriazole-based agent. A metal deactivator, a defoaming agent for silicones, etc. that can be added as necessary. Those that do not form solids by reaction with ammonia should be selected. Therefore, phenolic antioxidants cannot be used. Also, lubricating oils that may react with ammonia, such as polyol esters, should not be mixed, and mineral oil-based lubricating oils that do not dissolve in ammonia should not be mixed.

Next, the second invention using the working fluid composition will be described in detail. In the present invention, an ammonia refrigerant and a lubricating oil that can be dissolved in the ammonia refrigerant and do not separate into two layers even at the evaporation temperature of the refrigerant are filled in a refrigeration apparatus, and the charging ratio of the two is ammonia. A refrigerant is filled with lubricating oil at least 2% by weight to constitute a refrigeration or heat pump cycle.

The combination of ammonia and lubricating oil varies depending on the type of compressor.Basically, as long as lubricating performance is maintained, it is preferable to reduce lubricating oil as much as possible to increase heat transfer efficiency,

For example, in a cooling device at Kibashi W, where a rotary compressor is used, generally, the IB mixing ratio of the ammonia refrigerant and the oil is 70 to 97:;-] Even if it is set to about 0 to 3, sufficient lubricity and refrigeration capacity can be obtained, leading to a significant improvement in performance as described later.

In other words, if the lubricating oil is dissolved by 3% or more, the dissolution of the oil easily enters the sliding part of the compressor, and the amount of galling is reduced, and the configuration of the refrigeration cycle is extremely simplified.

In addition, the ultrafine diamond having an average particle diameter of at least 150 A or less, preferably about 50 A or less in the lubricating oil constituting the working fluid composition. By adding the coated ultrafine diamond to the graphite, no problem occurs even if the blending ratio of the lubricating oil is reduced to about 2%.

Such a diamond is, for example, (NEW DA I AMO D 199 1 V0 L8

No. 1, Characteristics of ultrafine particle diamond padder by new explosion method and its application), explosive substances are exploded in an explosion chamber filled with inert gas. A cluster diamond obtained by refining the synthesized ultrafine particle diamond. A carbon cluster diamond in which the graphite diamond is coated on the cluster diamond is often used. By adding 2 to 3% by weight of this to the lubricating oil, it is possible to reduce the blending ratio of the lubricating oil in the working fluid to 2% by weight.

The lubricating oil does not separate into two layers even at the evaporating temperature of the refrigerant, and because of its excellent low-temperature fluidity, separated oil adheres to the heat exchange coil not only on the condenser side but also on the evaporator side. As a result, not only is the heat transfer efficiency greatly improved, but also the oil recovery mechanism and the oil separator do not need to be provided in the refrigeration cycle. Dramatically simplified.

Also, in the compressor, the lubricating oil enters the sliding part while being dissolved in the refrigerant, which helps to further prevent galling.

In this case, the working fluid composition obtained by mixing the compressor and the lubricating oil after being compressed by the compressor is configured to circulate through a refrigeration and heat pump cycle without interposing an oil collector. You may.

In this case, even if the lubricating oil filling ratio is 10% by weight or more, a certain amount of lubricating oil is stored in the compressor, so that the blending of the lubricating oil in the refrigeration cycle should be adjusted especially in the evaporator. The mixing ratio of the lubricating oil in the working fluid composition can be set to not more than%, and more preferable heat transfer efficiency can be obtained.

Further, a part of the oil in the working fluid composition after being compressed by the compressor may be configured to be charcoalable into the compressor. In the latter case, in particular, the mixing ratio of lubricating oil is increased on the compressor side, and lubrication guided to the circulation cycle, especially to the evaporator side It becomes easy to reduce the oil blending ratio as much as possible.

Of course, the present invention can be applied to a single-stage compression type refrigeration system and also to a two-stage compression type refrigeration system,

In addition, since the composition has excellent lubricity and compatibility even at a temperature lower than the evaporation temperature of the refrigerant, the composition after passing through an expansion valve or an intercooler is introduced from above the evaporator. This makes it possible to adopt a top-feed structure that reduces the amount of refrigerant (composition) cycled and achieves a high cooling / freezing effect without having to adopt a so-called full structure. I can do it.

Further, the composition is compatible with the lubricating oil even at a temperature lower than the evaporation temperature of the refrigerant, but may be separated under the severe conditions of low-temperature vaporization in the evaporator. With a feed-feed configuration, the separated oil is introduced directly into the compressor, causing knocking and other problems.

There, an oil sump for temporarily storing the separated oil, and a lubricating oil in the oil sump, for example, as in a double riser, are introduced into the introduction pipe for communicating between the evaporator and the compressor. It is preferable to provide a remixing section for remixing with the working fluid composition introduced into the compressor in the passage.

The problem of insolubility of ammonia and refrigerant has been solved by taking the above-mentioned method.

The problem of the strong corrosiveness and conductivity of ammonia, especially the corrosion of copper, has not been solved, and it is difficult to apply it to hermetic compressors, especially household refrigerators, unless the problems are solved.

Therefore, the present invention relates to an ammonia refrigeration apparatus using a hermetic-type amphibian compressor in which an electric motor is directly connected to an ammonia refrigerant compressor.

On the inner peripheral surface side of the stator core located on the periphery ffl of the rotor on the motor side, the rotor is surrounded by a predetermined gap with the rotor via a hermetic seal portion, and the rotor inner space and the compressor are A technology is proposed in which a conducting portion is provided between which the composition can be conducted.

According to this invention, since the stator side on which the winding is mounted is isolated from the rotor storage space through which the ammonia refrigerant and the like flows by the airtight seal portion, the winding and the like are affected. There is no danger that the lubricating oil-containing composition flows into the rotor storage space side, so there is no danger that the mm of the bearing portion such as the rotating shaft of the rotor will be affected. It is possible to equalize the fluid composition in both spaces-in this case, the airtight seal may be constituted by a cylindrical can surrounding the | π | trochanter. In the case of a river flow, the excitation of the stator wire loop The alternating magnetic flux forms a rotating magnetic flux and penetrates the can in the gap, and the force for rotating the stator An eddy current flows through the can, causing eddy current loss, and the loss accounts for about half of the motor loss. Heats the motor and reduces efficiency. Therefore, the stator core is configured as a pressure-resistant sealed structure container, and an insulating thin film is interposed on the inner peripheral side of the stator core, or the stator faces the rotor of the groove after the winding of the stator core is inserted. A seal member may be provided on the front side to be sealed, and the inside of the groove may be hermetically sealed via the seal member.

As a result, the above-mentioned disadvantages of the can can be eliminated, and the stator core itself functions as a pressure-resistant container, so that the can becomes unnecessary, and the stator core is also formed of a thick field core. As a result, sufficient pressure resistance can be obtained.

Since the composition is configured to be able to leak from the transmission shaft portion that transmits the rotation of the rotor to the compressor side, lubrication on the motor side is facilitated, and an incomplete seal is provided. Its configuration is easy.

"Brief description of the drawings"

FIG. 1 is a schematic view showing a single-stage compression type direct expansion refrigeration apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a two-stage compression type cryogenic freezing apparatus according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing a single-stage compression type direct expansion refrigeration apparatus according to another embodiment of the present invention.

FIG. 4 is a vertical sectional view of a hermetic compressor directly connected to an electric motor according to an embodiment of the present invention. The figure is an enlarged view of the main part showing the cross-sectional structure of the stator in FIG.

FIG. 6 is a schematic diagram showing a single-stage compression type direct expansion refrigeration apparatus according to the related art.

Fig. 7 is a schematic diagram showing a conventional two-stage compression type cryogenic freezing apparatus. "Best mode for carrying out the invention"

First, as lubricating oils, polyether compounds shown in Table 1 (Examples 1 to 8), naphthenic mineral oil-based refrigerating machine oil shown in Table 2 (Comparative Example I), branched-chain alkylbenzene (Comparative Example 2) and Applying (poly) ether compounds (Comparative Examples 3 to 8), compatibility with ammonia, sintering of pholex, color of sample before and after bomb test in ammonia atmosphere, total acid Changes in the value and appearance were measured and evaluated.

The physical properties of the naphthenic ore-based refrigerating machine Shane of Example 1 and the branched-chain alkylbenzene of Comparative Example are as follows. Naphthenic mineral oil type branched chain type

Refrigeration oil Alkylbenzene

Density 0.888 0.870

Kinematic viscosity cSt (100 ° C) 4.96 4.35

Flash point 180 178 The outline of various test methods used for evaluation of the composition of the present invention is as follows.

Average molecular weight: 1. The weight average molecular weight was measured by [] PC (gel permeation chromatography).

Kinematic viscosity: Measured based on JIS K2283.

Compatibility with ammonia: 5 g of sample oil and 1 g of ammonia were sealed in a glass tube, cooled at a rate of 1 ° C / min from room temperature, and the temperature at which two layers were separated was measured.

Flex seizure load: The flex seizure load was measured in accordance with ASTM D-3 2 3 3 —73.

Cylinder test: 50 g of sample oil was placed in a 300 ml cylinder filled with 3 m of iron wire 1.6 mm in diameter as a catalyst, and pressurized with ammonia to 0.1 kg kg SGSG. Furthermore, the pressure was increased to 5.7 kg Z cm ² G with nitrogen gas. Thereafter, the mixture was heated to 1 δ (TC and kept at that temperature for 7 days. After cooling to room temperature, ammonia was removed from the sample oil under reduced pressure, and the hue and total acid value before and after the test were measured. Changes in the appearance were visually observed, and the stability of the sample was evaluated in an ammonia atmosphere.

No change: No change in appearance before and after the test

Solidification: The sample solidified after the test

The results of the test are shown in Tables 1 and 2.

Tables 1 and 2 show that the polyether compounds of Examples 1 to 8 are excellent in compatibility with ammonia, lubricity, and stability under an ammonia atmosphere. A mixture of such a polyether compound and ammonia is filled into an ammonia compressor and used to exhibit its function sufficiently. As a result, the ammonia compressor can be made compact and maintenance-free, which has a special effect such as expanding the application of the ammonia compressor.

However, the naphthenic ore-based chillers, the branched-chain alkylbenzenes, and the (poly) ethers of Comparative Examples 3 to S shown in Table 2 are insoluble at room temperature. However, it can be seen that even if it is compatible at a low temperature of 150 ° C., it is individualized by a bomb test. As a result, these oils cannot be used in refrigeration cycles that repeatedly undergo compression / condensation / expansion.

Next, a refrigeration system using a working fluid composition obtained by mixing such a lubricating oil and a fangny refrigerant will be described.

FIG. 1 shows a single-stage compression-type direct expansion refrigeration apparatus according to an embodiment of the present invention, in which R-7117 (ammonia refrigerant) is used as a refrigerant and the polystyrene of Example 1 is used as a lubricating oil. An example is shown in which ether is filled in a frozen cycle at a ratio of 90 parts by weight: 10 parts by weight.

In the figure, reference numeral 11 denotes a refrigerant compressor. The refrigerant working fluid formed by dissolving the ammonia refrigerant condensed by the compressor 11 and the lubricating oil passes directly to the condenser 12 without passing through the oil separator. Led, the condenser 1 2 li

Within δ, it is condensed and liquefied by heat exchange with the cooling water (cooling water pipe 18) (acquisition heat: around 30 ° C).

After the condensed working fluid is stored in the high-pressure receiver 14, it is decompressed and vaporized by the expansion valve 丄 3, and is discharged from the inlet 15 a provided at the upper end of the evaporator 15. After being introduced into the evaporator 15 by the top feed, it exchanges heat with the blast load supplied by the fan 16 (acquisition heat: about 15 to 120 ° C), The refrigerant is sucked into the intake side of the compressor 11 through the heater 17 and the refrigeration cycle is repeated.

Here, as known, the double riser 17 has a main pipeline 17 1 provided with a U-shaped local oil reservoir 17 2 provided at the outlet side of the evaporator 15 outlet 15 b. And a bypass line 173 that bypasses the main line, and the main line while the oil slightly separated by evaporation in the evaporator 15 is stored in the oil reservoir 172. When the main line 17 1 is closed by an oil sump by guiding the low-pressure suction pipe 19 side through 1 71 and making the bypass line 1 73 into a thin tube to provide throttling resistance, The blocked oil is led out to the low-pressure suction pipe 19 by the flow rate of the vaporized refrigerant containing the lubricating oil passing through the bypass passage 17 3, and is mixed and dissolved again into the suction side of the compressor 11. It is a guide.

Therefore, according to the embodiment, an oil separator or the like is not required. Therefore, unlike the prior art shown in FIG. 6, an oil reservoir is not provided at the bottom of the liquid receiver, and a double riser 17 is not provided. However, since a local oil sump 17 2 is provided, it is mixed and melted again and introduced into the compressor 11 侧. becomes unnecessary, rhino _r the present embodiment cycle structure is very simplified in order lubricating oil compatible refrigerant even less evaporation temperature, above the vacuum refrigerant expansion valve 1 3 after passing through the evaporator 1 5 Top feed to be introduced The structure allows the refrigerant to pass through the evaporator along with the IS force, which eliminates the need for a so-called liquid-filled structure. As compared with the conventional example shown in FIG. 6, even if the amount of the refrigerant was reduced by 10% or more in the II amount ratio, a higher cooling effect could be obtained as compared with the conventional example.

In the present embodiment, even if the ammonia refrigerant and the lubricating oil were filled at a ratio of 90 A: 10 parts by weight, a certain amount of the lubricating oil was stored in the compressor 11, so that the refrigeration system was not used. Since the ratio of the amount of the working fluid composition circulating in the vessel is lower than the above filling weight ratio, and particularly the mixing ratio of circulating in the evaporator is 5% or less, the heat transfer efficiency on the evaporator side is further improved.

The compressor is suitable for a variable blade type rotary compressor or a reciprocating compressor. 6

Further, in this embodiment, the evaporation temperature is set to 115 to 12 (TC and the force operated with a higher compression ratio than that of the conventional technique). For a long period of time without bridging !: High reliability can be obtained.

In addition, the lubricating oil does not adhere to the wall of the heat exchange coil in the pre-condenser 12 or evaporator i5, and the heat transfer efficiency is higher than that of the conventional example shown in Fig. 6 using a naphthenic mineral oil-based refrigerating machine oil. By more than 60%, it has improved.

In addition, since the ammonia and the lubricating oil constituting the working fluid have the ability to dissolve water, there is no need to provide a dehumidifying agent such as silica gel or a dehumidifying mechanism as in a fluorinated refrigeration cycle. Good.

Now, the working fluid is required to increase the proportion of the refrigerant within a range where the lubricity of the compressor i i is not reduced. Actually, when the lubricating oil is set to 5% by weight or less, the lubricating ability is reduced.

Therefore, in such a case, as described above, a cluster diamond having an average particle size of about 50 A or less. A carbon cluster in which the graphite is coated on the cluster diamond. By adding 2 to 3% by weight of a diamond to the lubricating oil, the blending ratio of the lubricating oil in the working fluid could be further reduced.

Also, as shown in FIG. 3, for example, the double riser 17 also uses a liquid refrigerant after passing through a condenser 14 to use a working fluid composition containing oil that has been slightly separated by evaporation in the evaporator 15. Is heated by the heat exchanger 150, so that the separated oil melts in the composition at once and the double riser becomes unnecessary.

In order to improve lubricity, the mixing ratio of the lubricating oil in the working fluid composition was increased, and the output of the compressor was changed to the Shan separator 25 and the separator. A measure may be taken to provide a return circuit 2f; for returning the oil separated in 25 back to the compressor 11 side.

In particular, in the case of an oil-cooled screw compressor, the oil separator 25 and the oil separated by the separator 25 are returned to the compressor side again at the outlet side of the compressor 11 1. 6 is better.

In this case, the filling weight specific gravity of the ammonia refrigerant and the lubricating oil is 90 to 80 parts by weight: Even if the filling is performed at a ratio of 10 to 20 parts by weight, the compressor 11 / oil separator 25 / powder Increase the mixing ratio of lubricating oil in the closed cycle of circuit 26, and minimize the mixing ratio of lubricating oil in other refrigeration cycles.For example, 90% or more of lubricating oil on compressor 11 side, evaporator 1 It is possible to set the mixing ratio of the lubricating oil on the 5 side to 3% or less, and further to about 0.5%.

Further, as shown in Examples 4, 6, 7, and 8 in the above table, the liquid pump is recirculated by forming the working fluid using a lubricating oil having a two-layer separation temperature of 150 ° C or less. A cryogenic refrigeration system can be easily configured without taking a ring system configuration. FIG. 2 shows a brief description of the structure based on FIG. 2. R-717 (ammonia refrigerant) is used as a refrigerant and the polyether of Example 6 is used as a lubricating oil. A cryogenic refrigeration system filled into a refrigeration cycle at a ratio of 5 parts by weight. 2) is a low-stage compressor, and the compressed working fluid in which the ammonia refrigerant and lubricating oil are compatible is mixed in an intercooler 22. 0. It is cooled to around C and guided to the high-stage compressor 11.

The refrigerant working fluid compressed by the high-stage compressor] 1 is directly led to the condenser 12, and exchanges heat with the cooling water (cooling water pipe 18) (condensed heat: 3) in the condenser 12. (Around 5 ° C).

Then, after the condensed working fluid is stored in the high-pressure receiver 14, it is decompressed and vaporized by the expansion valve 20 to cool the intermediate cooler 22 to about 110 ° C. The re-liquefied working fluid is introduced into the evaporator 15 from the inlet 15a provided at the upper end of the evaporator 15 by a top feed, and the blast load supplied from the fan 16 After the heat exchange (acquisition heat: -50 "C), the refrigerant is sucked into the intake side of the compressor 21 through the double riser 17 and the refrigeration cycle is repeated.

Therefore, in this embodiment as well, the oil sump and the oil recovery structure in the high-pressure receiver 1 and the intercooler 22 become unnecessary, and the low-pressure receiver and evaporator shown in FIG. A liquid pump recirculation cycle for circulating the refrigerant liquid is not required, and the configuration of the refrigeration cycle is greatly simplified.

As shown in Table 3, the working fluid composition used in this example It has good compatibility with the refrigerant even at a temperature of 50 "C below the temperature, and has good fluidity.Because it is as good as 4.5 seconds ago, it can take a top feed structure and use less refrigerant. In particular, it is possible to obtain a higher refrigerating effect than in the conventional example of the bottom feed structure, and the heat transfer efficiency in the cryogenic evaporator is improved.

In addition, since it is sufficient to provide only a local oil reservoir such as a double riser provided on the outlet side of the evaporator 15 and a remixing / melting structure, there is no need to pause for oil drainage. Can be continued for the R period, which facilitates unmanned operation and free maintenance.

By adopting the above configuration, the problem of insolubility of ammonia and refrigerant has been solved.

The problem of the strong corrosiveness and conductivity of ammonia, especially the corrosion of electrolytic copper wire, has not been solved, and it is difficult to apply it to hermetic compressors, especially refrigerators for home use, unless these problems are solved. is there ,,

The first is the application of canned motors.

That is, in a sealed electric motor directly connected to a fluid machine using an ammonia refrigerant, a cylindrical cylinder-shaped can is inserted and fixed between the stator and the rotor, and up to the stator located on the outer peripheral side of the can. The use of a can-type motor that does not leak ammonia refrigerant is considered.

However, high-density alternating magnetic flux is interlinked in the can, which increases eddy current loss and magnetic resistance in the air gap including the can, and generates a large amount of heat due to excitation loss and the like. Reduce the efficiency of

Therefore, there is no particular problem if the stator and the rotor can be partitioned without using a can and leakage of ammonia on the stator side can be sealed.

Fig. 4 and Fig. 5 show an embodiment of such a configuration, showing a main configuration of a hermetic compressor in which an electric motor and a screw compressor are directly connected. First, the horizontal structure of the screw compressor A side is shown. To explain, 31 is a suction hole which is taken in to compress the compatible working fluid as shown by an arrow, and 32 is a refrigerant gas compressed by the screw euro 30. A discharge port for discharging to the condenser side, 33 is a rotor housing that covers this, 34 A is a bearing fitted to a disc-shaped bearing housing 35, and a rotating shaft 36 on the motor B side The sprocket shaft mated with the mouth shaft 37a is supported. The rotor shaft 37 b on the other side is supported by a bearing 34 B.

In this case, the rotor shaft 37a and the bearing 34a constitute an imperfectly sealed state so that the working fluid composition can be introduced from the compressor A side to the electric motor 13 side. On the side of housing 35, the operation flowed to motor B side A return hole 39 for fluid is provided to equalize the pressure in the rotor 41 space on the compressor A side and the motor side.

On the other hand, the motor B side includes a rotor 41 fixed to the rotating shaft 36, and a stator 42 surrounding the rotor 41, and the stator 42 shown in FIG. Thus, a stator core 43 formed by laminating a large number of field core plates 43a and a cross section extending in the axial direction on the inner peripheral surface side of the stator core 43. The winding wire 45 housed in the U-shaped open groove 44 and 45 a located on both axial sides of the stator core 43 are portions where the winding coil is extended. Then, the stator core 43 is air-tightly sealed by applying an insulating resin coating agent or other adhesive 46 on the lamination of a large number of field core plates 43a. Alternatively, both are solidified integrally by thermocompression bonding with a thermally fusible insulating film 46 interposed therebetween, and are airtightly maintained to withstand pressure 9. Further, the non-magnetic thin plate 47 or the resin thin film 47 is press-fitted on the inner peripheral surface side of the stator core 43 to form a coating, thereby further improving the airtightness.

The stator core 43 has a substantially cylindrical shape, and the both ends of the stator core 43 in the axial direction are fixed to the bearing housing 35 on the compressor A side in a gas-tight manner by the flange 48 a of the outer frame housing 48 and the flange 48 a. The rotating shaft 36 is brought into contact with the flange portion 28a of the end plate housing 28 integrated with the free end bearing 29 of the rotating shaft 36 to be integrally and airtightly fixed.

According to such a configuration, the stator core 43 is located on the free end side of the outer frame housing 48 and the rotary shaft 36 airtightly fixed to the compressor A side at both ends as described above. end plate-shaped housing 2 8 acts as a by Li pressure vessel to the cooperative operation between these members to be integrally fixed obtained, therefore, the compressed refrigerant gas 2 0 K g Z m ² Sufficient pressure resistance can be ensured even for refrigerators that extend over time.

On the other hand, since the winding 45 housed in the groove 44 of the stator core 43 is located in the same space as the rotor 41, the compressor A in an imperfectly sealed state is provided. Since the working fluid composition containing the corrosive ammonia refrigerant intrudes into the electric motor B from between the rotor shaft 37a and the bearing 34, the winding 4 is provided together with the rotor 41. Corrosion-resistant insulation must be applied, but it is difficult to perform ammonium insulation treatment on windings.

Therefore, as shown in FIG. 5 (B), the open groove 44 is filled with a binder tree ^ 49, and the insulating resin thin film 47 'is covered on the inner peripheral side thereof to be airtight. As shown in FIG. 5 (A), the binder resin is filled into the opening 44, and both ends are placed at the open end of the opening 4 as shown in FIG. A sealing plate 27 with a tapered side is fitted. A back pressure is applied from the back side of the sealing plate 27 by the refrigerant gas pressure in the container. The ends can be fitted and hermetically sealed. As a result, while the stator winding 4 4 is fixed in the ^ groove 12, the m-face is closed, and at the same time, strong mechanical strength, touch resistance and airtightness can be maintained. And can

“Usability on 槳”

INDUSTRIAL APPLICABILITY The lubricating working fluid composition for a lubricating shroud and a refrigerator according to the present invention has excellent dissolution stability even at a low temperature with ammonia, and exhibits excellent lubricating properties in an ammonia refrigerant atmosphere, and is compressed. No solid matter is generated during the C operation, and therefore, the Shane recovery equipment, which was indispensable in the conventional ammonia refrigerant refrigeration system, can be omitted, and therefore, it can also be applied as a small refrigerator. This will be possible. The refrigeration apparatus of the second invention is configured such that the working fluid composition of the lubricating oil and ammonia circulates through a refrigeration or heat pump cycle, thereby simplifying the apparatus configuration and improving heat transfer efficiency. Thus, it is possible to provide a cooling device that is extremely advantageous in practice.

In particular, in a preferred embodiment of the present invention, ammonia is insoluble in the lubricating oil and the erosion is eliminated, whereby an ammonia sealed compressor can be easily provided. Is extremely large.

Table 3 Dissolution characteristics of ammonia and refrigerator Characteristics Compatibility C Flowability

(Two-phase;;! Temperature)-30 j-δ 0 naphthenic material? 物!] Room temperature g 1 0 3 1 3 〇 0 or more Oku Example 6-0! Less than !

1

(;;!;

: Then i (δ1) to Ν (i! ;;; ::; 7:

2 ~? cooled in c / mi _n, two i min g; the degree m

^: <;'l ί !:: () ° C for 1 minute !! ij shake, (TC' Ode 1 で 'ί,'. '!]': 'Ά (Sk: (i)

m; -i 0 for 0 minutes !; · '; (Jfi ϋϊ)

After ¾, ';;! I is 50 m;!! ¾ に

1.

Talented Kisibuchire

1: 1 (! 1 m

Claims

The scope of the claims

I. A working fluid composition for a refrigerant compressor using ammonia as a refrigerant, comprising a mixture of ammonia and one or more polyether compounds represented by the general formula (I).

Rt-[-0- (P0) _m- (E0) _n -R ₂ ] x (I)

(In the general formula (I), R _t is a hydrocarbon group having 16 carbon atoms, R ₂ is an alkyl group having 16 carbon atoms, P 0 is an oxypropylene group, E 0 is an oxyethylene group, X is an integer of 1 to 4, m is a positive integer, and n is 0 or a positive integer.)

2. The working fluid composition according to claim 1, wherein in the general formula (I), the total number of carbon atoms of and R ₂ is 10 or less.

3. The working fluid composition according to claim 2, wherein and R _{2 in} the general formula (I) are each independently an alkyl group having 1 to 4 carbon atoms.

4. The working fluid composition according to claim 3, wherein and R _{2 in} the general formula (I) are each independently a methyl group or an ethyl group, and X is 1.

5. The working fluid composition according to claim 1, wherein and R _{2 in} the general formula (I) are each independently an alkyl group having 14 to 14 carbon atoms, and X is 2 to 4.

6. The working fluid composition according to claim 1, wherein in the general formula (I), a ratio of mZ (m + n) is 0.5 / 5-1.0.

7. The working fluid composition according to claim 1, comprising 2% by weight or more of the polyether compound represented by the general formula (I).

8. The working fluid composition according to claim 1, wherein the average molecular weight of the polyoxyalkyl ether compound is from 300 to 180 °.

9, when the evaporation temperature is used for the following cryogenic refrigeration apparatus-4 0 ° C, before Symbol working fluid composition of claim 1 wherein using a methyl group at R _t of general formula (I).

10.The working fluid composition according to claim 1, wherein an ultrafine diamond having an average particle size of 150 A or less, preferably an average particle size of approximately 50 A or less is added to the working fluid composition. .

II. Freeze the ammonia while circulating it with one or more polyether compounds represented by the general formula (I) through a circulation cycle including a refrigerant compressor, a condenser, an expansion valve and an evaporator. Is an ammonia refrigeration system comprising a heat pump cycle.

-[-0- (P0) _m- (E0) _n -R ₂ ] x (I) In (general formula U), is a hydrocarbon having〗 —6 carbon atoms ;;!, R _≥ is an alkyl group having 1 to 6 carbon atoms, P〇 is an oxypropylene group, E〇 is an oxyethylene group, X is an integer of 1 to 4, πι is an integer of IE, and n is 0 or a positive integer. )

12. An ammonia refrigerant and lubricating oil that can be dissolved in the ammonia refrigerant and do not separate into two layers even at the evaporation temperature of the refrigerant are filled in the refrigeration apparatus, and the filling ratio of the two is adjusted to ammonia. Ammonia refrigeration system characterized in that a refrigerant or a heat pump cycle is configured by filling lubricating oil at 2% by weight or more with refrigerant.

13. The ammonia according to claim 12, wherein a part of the lubricating oil in the working fluid composition in which the ammonia refrigerant and the lubricating oil are dissolved after being compressed by the compressor can be returned to the compressor side. Refrigeration equipment

14. The compressor and the lubricating oil contained in the working fluid composition in which the lubricating water is dissolved are introduced into the evaporator via the condenser and the expansion valve by the compressor.詰詰詰詰詰装置詰アアア詰アアアアアア

15.The working fluid composition in which the ammonia refrigerant and the lubricating oil condensed in the condenser are dissolved can be introduced into the expansion valve or the nozzle and the intermediate cooler without separating the refrigerant and the lubricating oil. Claim 11. The fan refrigerator according to claim 11.

16.The working fluid composition, in which the ammonia refrigerant and the lubricating oil have passed after passing through the expansion valve or the intercooler, is used to discharge the working fluid composition from the inlet provided at the top of the evaporator to the outlet provided at the bottom of the evaporator. 3. The ammonia refrigeration apparatus according to claim 1, wherein the ammonia refrigeration apparatus is configured to be capable of being introduced with a top feed toward the side.

17) An oil sump for storing the lubricating oil separated on the evaporator side at an intermediate point of the introduction pipe connecting the compressor from the evaporator, and the lubricating oil in the oil sump as appropriate. The ammonia refrigeration apparatus according to claim 1, further comprising a mixing section for remixing with the working fluid composition introduced into the compressor in the pipeline.

18. The working fluid composition obtained by adding at least an ultrafine diamond having an average particle diameter of 1 δ 0 Α or less, preferably an average particle diameter of about 50 A or less, to the lubricating oil. The ambition used was the Ammonia refrigeration of the war [2 _]

19.The method according to claim 1, wherein the working fluid composition derived from the evaporator is heat-exchanged with the retained heat of the working fluid composition after condensation in a condenser, and then introduced into the compressor. Ammonia cooling device described in 2

20.Ammonia refrigeration equipment according to claim 12, wherein a sealed-type ammonia compressor having an electric motor directly connected to the ammonia refrigerant compressor is used. On the inner peripheral side of the stator core located around the rotor on the motor side, the rotor is surrounded by a predetermined gap with the rotor via a hermetic seal, and the space between the rotor inner space and the compressor is provided. An ammonia refrigeration apparatus characterized by having a conducting portion through which a composition can pass.

21. The ammonia refrigeration apparatus according to claim 20, wherein said airtight seal portion is a can surrounding a rotor.

22.The stator core located around the rotor on the motor side as a pressure-resistant sealed structure container, and an insulating thin film is interposed on the inner peripheral side of the stator core. The ammonia refrigeration apparatus according to 0.

23. A stator core located around the rotor on the motor side is configured as a pressure-resistant sealed structure container, and rotation of the groove after insertion of the winding of the stator core is performed.

Two

21. The ammonia refrigeration apparatus according to claim 20, wherein a seal member is disposed on the ffi side before the child, and the inside of the groove can be hermetically sealed via the seal member.

24. A method of lubricating a refrigeration compressor, comprising lubricating an ammonia refrigerant compressor with one or more lubricating oils of the ether compound represented by the general formula (I).

-! -C-0- (P0) _m- (E0) _n -R ₂ ] x (I)

(In the general formula (I), R _t is a hydrocarbon group having 1 to 6 carbon atoms, R ₂ is an alkyl group having 16 carbon atoms, P〇 is an oxypropylene group, E 0 is an oxyethylene group, X Is an integer from 1 to 4, m is a positive integer, and n is ◦ or a positive integer.

25. The lubricating method for a refrigeration compressor according to claim ₂₄ , wherein in the general formula (I), the total number of carbon atoms of and R _≥ is 10 or less.

2 6. The 1 ^ and R ₂ force independently of the general formula (I), having 1 carbon - four lubricating how ammonia refrigeration compressor according ¾ 2 4, wherein the alkyl ¾ of.

27. The lubricating method for a refrigeration compressor according to claim 24, wherein R t and R _{2 in} the general formula (I) are each independently a methyl group or an ethyl group, and X is 1. .

. 2 8 Formula (I) of the R ₂ were each independently having 1 carbon - an alkyl group of 4, moreover X 2 - 4 a is claimed paragraph 2 4 according refrigerating compressors Lubrication method.