JPH05248735A - Compression type freezing machine - Google Patents

Abstract

PURPOSE:To obtain a compression type freezing machine capable of efficiently removing moisture in a refrigerant and gas produced by the decomposition of freezing machine oil, preventing the direct contact of the freezing machine oil with sorbents, preventing the decomposition of the freezing machine oil, and preventing the clogging of capillaries due to the outflow of the sorbents and the abrasion of sliding portions. CONSTITUTION:In a compression type freezing machine, sorbents are employed in a refrigerant flow passage to remove moisture contained in a refrigerant and gas produced by the decomposition of freezing machine oil. A sorbent pack 11 in which the sorbents 12 are covered with permeable membranes 13 having gaseous molecule permeability is brought into contact with the refrigerant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression refrigerating machine equipped with an absorbent, and more particularly to a compression refrigerating machine used as an electric refrigerator, room air conditioner, car air conditioner or the like.

[0002]

2. Description of the Related Art In a compression type refrigerator used for household electric refrigerators, room air conditioners, car air conditioners, etc., a dryer in which a molded body such as silica gel or molecular sieve is packed in a metal net or cloth is placed in a refrigerant pipe, Is removing water.

In such a compression type refrigerator, 1, CFC (chlorofluorocarbon) is replaced by 1,
HFCs (hydrofluorocarbons) such as 1,1,2-tetrafluoroethane have been used as ozone layer nondestructive refrigerants.

However, H, which is such a new refrigerant,
FC is structurally more hygroscopic than conventional CFCs. Further, polyalkylene glycol or its derivatives, carboxylic acid ester derivatives, carbonic acid ester derivatives and the like, which have been developed as refrigerating machine oils for HFC, have higher hygroscopicity than conventional refrigerating machine oils such as mineral oils and alkylbenzenes. Therefore, the conventionally used dryer cannot sufficiently remove water.

Further, polyalkylene glycol or its derivatives, carboxylic acid ester derivatives, carbonic acid ester derivatives, etc., which have been developed as refrigerating machine oils for HFC, are
Compared with conventional mineral oils and refrigerator oils such as alkylbenzene, stability under heating and stability in the presence of water are inferior, and as a result, carbon dioxide gas, ethylene oxide,
It is feared that a decomposition gas such as propylene oxide is generated, which causes a safety problem due to an increase in pressure in the refrigerator, or deteriorates the refrigeration performance.

Therefore, as a sorbent for a dryer for HFC, one having a low decomposability and a high hygroscopic property has been developed. For example, molecular sieves XH-7 and XH-9 having a pore size of 3 to 4 angstroms have been developed. (Manufactured by Union Showa Co., Ltd., trade name), and Zeorum A-39, A-4SH
(Made by Tosoh Corporation, product name), etc. In addition to this, JP-A-3
No. 28168 discloses that sodium fluoride is used as a sorbent for hydrofluoric acid which is a decomposition component of HFC.

In the case of an electric refrigerator, a dryer using these sorbents has a structure in which silica gel particles or molded molecular sieve particles are packed in a copper pipe partitioned by a metal net, and the filler is more than conventional. The internal volume is designed so that it can be filled in large quantities. Further, in a car air conditioner, silica gel particles and molecular sieve particles are packed in a liquefied refrigerant receiver sandwiched between metal mesh plates.

However, in the conventional compression type refrigerator using such a dryer, the refrigerant and the refrigerating machine oil are in direct contact with the sorbent, so that the sorbent, which is a strong base containing sodium and potassium, freezes the sorbent. The decomposition of machine oils, especially carboxylic acid ester derivatives and carbonic acid ester derivatives, is promoted. In addition, the sorbent, which has been broken into small pieces, flows out together with the refrigerant, causing problems such as clogging of the capillaries and abrasion of sliding parts of the compressor and pump.

[0009]

In order to solve the above problems, the object of the present invention is to efficiently remove the water in the refrigerant and the gas produced by the decomposition of the refrigerating machine oil, and to collect it with the refrigerating machine oil. It is an object of the present invention to provide a compression refrigerating machine capable of preventing direct contact of an adhesive agent to prevent decomposition of refrigerating machine oil, and preventing clogging of capillaries and abrasion of sliding parts due to outflow of a sorbent agent.

[0010]

The present invention is the following compression type refrigerator. (1) In a compression refrigerator in which a sorbent is placed in the refrigerant channel to remove water contained in the refrigerant and a gas generated by decomposition of refrigerating machine oil, the sorbent permeates gaseous molecules. A compression type refrigerator characterized in that a sorbent pack coated with a permeable membrane is brought into contact with a refrigerant. (2) The compression refrigerator according to (1) above, wherein the refrigerant is hydrofluorocarbon. (3) The compression refrigerator according to (1) or (2) above, wherein the refrigerator oil is a compound having a carboxylic acid ester bond or a carbonic acid ester bond. (4) The sorbent is selected from alkali metals or alkaline earth metals, their oxides or hydroxides, silica gel, molecular sieves, phosphoric anhydride and liquid bases.
The compression refrigerator according to any one of (1) to (3) above, which is one or more kinds. (5) The permeable membrane is polyimide, polyamide, polyacetal, polyester, polycarbonate, polyether,
Polysulfone, polyethylene, polypropylene, polypropylene copolymer, polybutene-1, poly-4-methylpentene, poly-4-methylpentene copolymer, butyl rubber, hydrogenated NBR, EPDM, silicone rubber, acrylic rubber, fluorine rubber and composites thereof. The compression refrigerator according to any one of the above (1) to (4), which is a membrane composed of one or more substances selected from the body. (6) The compression type refrigerator according to any one of (1) to (5) above, wherein the compression type refrigerator is an electric refrigerator, a room air conditioner or a car air conditioner.

The compression refrigerating machine to which the present invention is applied collects the refrigerant compressed by the compressor and condensed by the condenser from the capillary or the expansion valve to the evaporator to evaporate and circulate the refrigerant. A binder is arranged to remove the water contained in the refrigerant and the gas produced by the decomposition of the refrigerating machine oil. Examples of such a compression refrigerator include an electric refrigerator for home use, a room air conditioner, and a car air conditioner.

The refrigerant used in the present invention is HFC
, But other ones may be used. HFC is a hydrocarbon to which fluorine is bound, and is non-destructive to the ozone layer,
1,1,1,2-Tetrafluoroethane (R-134
a), 1,1,1,1-tetrafluoroethane (R-1
34), 1,1-difluoroethane (R-152a) and the like.

As the refrigerating machine oil, those conventionally used can be used, but those having a carboxylic acid ester bond or a carbonic acid ester bond are particularly preferred. Examples of the carboxylic acid ester bond-containing refrigerating machine oil include polyhydric alcohols having C ₁₅ or less, trihydric or higher, and C _{2 to} C ₁₈ monohydric fatty acid esters disclosed in JP-A-3-128992.
Ester disclosed in JP-A-3-21749, JP-A-4
-20597 can be used, and examples of the carbonate ester bond-containing refrigerating machine oil include carbonate esters shown in JP-A-4-18490, but the invention is not limited thereto. ..

The sorbent is a concept including an adsorbent and an absorbent, and removes moisture contained in the refrigerant and volatile product gas produced by decomposition of the refrigerating machine oil by sorption, that is, adsorption and / or absorption. It is a drug that can. The produced gas includes hydrogen fluoride, hydrogen chloride, carbon dioxide, ethylene oxide, propylene oxide and the like. These volatile gas and water are circulated together with the refrigerant to reduce the refrigerating efficiency, so that they are removed by the sorbent.

As sorbents for water, Li, N
a, K, Rb, Cs and other alkali metals and oxides thereof, hydroxides, Be, Mg, Ca, Sr, Ba and other alkaline earth metals and oxides and hydroxides thereof, as well as silica gel, molecular sieves, Activated carbon and phosphoric anhydride can also be used. As the sorbent for the produced gas, liquid bases such as mono-, di-, triethanolamine, aniline, dimethylaniline, and polyetherpolyamine can be used in addition to the sorbent for the water. These sorbents are preferably used properly according to the produced gas, and in this case, it is preferable to use a plurality of sorbents in combination. These sorbents may be used in solid form or in liquid form. The sorbent can also be used in a state of being carried on a sintered metal or a carrier having pores.

In the present invention, a sorbent pack in which these sorbents are coated with a permeable membrane permeable to gaseous molecules is used. Such a permeable membrane is a membrane in which moisture and product gas components to be sorbed are permeable in the form of gaseous molecules. Refrigerant may be permeable, but refrigerating machine oil must be impermeable. Further, as the permeable membrane, one that is not affected by the sorbent before and after sorption can be used.

The material of the permeable membrane is not limited as long as it has the above-mentioned permeability, but polyimide, polyamide, polyacetal, polyester, polycarbonate, polyether, polysulfone, polyethylene, polypropylene, polypropylene are preferred. Copolymer, polybutene-1, poly-4-methylpentene, poly-4-methylpentene copolymer, butyl rubber, hydrogenated NBR, EPDM, silicone rubber, acrylic rubber,
Membranes made of one or more selected from fluororubber and their composites can be used.

The thickness of the permeable membrane made of the above materials varies depending on the respective materials, the film forming method, the use environment, etc.
Generally, 0.005 to 5 mm is suitable. The pore size of the permeable membrane is not constant depending on the material, the film forming method, etc., but may be any pore size that allows moisture and generated gas to permeate in the form of gaseous molecules and does not permeate refrigerating machine oil. If the amount of water or decomposed gas generated is small, or if the material has high permeability, the film thickness can be increased considerably.For example, in the case of silicone rubber, the sorbent can be packed in a thick tube. Can be used.

The method of coating the sorbent with the permeable membrane is not limited, but in addition to the method of coating the sorbent or the carrier carrying the sorbent with the permeable membrane formed into a film in advance, the surface of the sorbent May be directly formed into a film and coated. In the case of coating with a permeable membrane that has been film-formed in advance, the sorbent pack can be formed by hermetically coating with a normal packaging method such as heat sealing or vacuum packaging. In the case of directly forming a film, the sorbent pack can be formed by directly coating the surface of the sorbent or the carrier by a casting method from a solution, a melt casting method, or the like.

[0020]

In the compression refrigerating machine of the present invention, a sorbent pack having a sorbent coated with a permeable membrane is placed in the refrigerant flow path and brought into contact with the refrigerant. The position for placing the sorbent pack is not limited, but a position from the condenser to the capillary or the expansion valve is preferable.

In the above-mentioned compression refrigerator, the refrigerant compressed by the compressor and released by the condenser to be condensed is guided from the capillary or the expansion valve to the evaporator, where it takes heat to evaporate and circulate. At this time, the water contained in the refrigerant and the gas produced by the decomposition of the refrigerating machine oil, in the form of gaseous molecules, permeate the permeable membrane of the sorbent pack and are sorbed by the sorbent and removed. At this time, the refrigerant and the sorbent are blocked by the permeable membrane, so that a concentration gradient is generated and the sorption of water and the generated gas is promoted.

Refrigerating machine oil circulates in the system in the form of mist, but is not directly contacted with the sorbent by being blocked by the permeable membrane. Therefore, even if the sorbent is basic, it does not accelerate the decomposition of the refrigerator oil. Further, since the sorbent is covered with the permeable membrane, even if the sorbent is collapsed, the powder does not flow out, and the capillaries are not clogged and the sliding portion is not abraded.

[0023]

EXAMPLES Examples of the present invention will be described below. 1 is a system diagram showing a compression refrigerator of an embodiment, FIG. 2 is a sectional view of a sorption device, FIG. 3 is a plan perspective view of a sorbent pack, and FIG. 4 is a sectional view taken along line AA.

In FIG. 1, a compression refrigerator 1 is connected through a condenser 2, a sorption device 3, a capillary or expansion valve 4, an evaporator 5 and a compressor 6 so that a refrigerant pipe 7 forms a circulation path. Is formed.

As shown in FIG. 2, the sorption device 3 is provided between the supports 9 and 10 in the column 8 whose both ends are connected to the refrigerant pipe 7.
It is a structure in which the sorbent pack 11 is filled. As shown in FIGS. 3 and 4, the sorbent pack 11 has a structure in which a granular or pelletized sorbent 12 (for example, sodium hydroxide) 12 is coated in a permeable membrane 13 by a vacuum pack. Reference numeral 14 is a heat seal portion of the permeable membrane 13.

In the compression refrigerator 1 described above, the refrigerant compressed by the compressor 6 and released by the condenser 2 to be condensed is guided through the refrigerant pipe 7 from the capillary or expansion valve 4 to the evaporator. When the sorbent pack 11 filled in the sorption device 3 is in the form of gaseous molecules, the moisture contained in the refrigerant and the gas produced by the decomposition of the refrigerating machine oil are taken in when they are circulated by taking heat away from the sorbent pack 11. It permeates the permeable membrane 13 and is adsorbed by the sorbent 12 and removed. At this time, the refrigerant and the sorbent 1
Since No. 2 is blocked by the permeable membrane 13, a concentration gradient is generated, and sorption of moisture and generated gas is promoted.

The refrigerating machine oil circulates in the system together with the refrigerant in the mist state, but is not blocked by the permeable membrane 13 and does not come into direct contact with the sorbent 12. Therefore, even if the sorbent 12 is basic, it does not accelerate the decomposition of the refrigerator oil. Since the sorbent 12 is covered with the permeable membrane 13,
Even if the sorbent 12 collapses, the powder does not flow out,
There is no clogging of the capillaries and abrasion of sliding parts such as pumps and compressors.

In the case where the sorbing device 13 of the present invention is replaced by a removing device consisting of only a permeable membrane, due to the principle of diffusion due to the concentration gradient, moisture enters from the outside into the refrigerator in a humid environment. At the same time, the refrigerant leaks, which is not preferable.

In a preferred embodiment of the present invention, R-134a is selected as the refrigerant, carbonate ester-containing lubricating oil or carboxylate ester-containing lubricating oil is selected as the refrigerating machine oil, and a rotary compressor type electric refrigerator is selected as the compression type refrigerator. In this case, the sorption pack is installed between the air-cooled condenser and the capillary or between the evaporator and the compressor inlet, and lithium hydroxide, sodium hydroxide or potassium hydroxide is used as the sorbent, and polypropylene is used as the permeable membrane. It is preferable to use a permeable membrane composed of polybutene-1, poly-4-methylpentene-1 and a copolymer thereof.

Example 1 The inside of a commercially available rotary compressor type refrigerator / freezer (manufactured by Matsushita Refrigerator Co., Ltd., trade name NR-38V3) was cleaned, and a pressure gauge, a rupture type safety valve, and a gas sampling valve were attached,
Further, instead of the dryer part, the sorption device 3 shown in FIG. 2 was attached at the position shown in FIG. This sorption device includes a sorbent 1
2 was filled with 10 g of sodium hydroxide, and a sorbent pack 11 covered by vacuum packing with a permeable membrane 13 as shown in FIGS. 2 and 3. As the permeable membrane 13, a poly-4-methylpentene-1 film (trade name Opulan, thickness: 50 μm) manufactured by Mitsui Petrochemical Engineering Co., Ltd. was used.

Next, a carbonic acid ester-containing refrigerating machine oil (manufactured by Mitsui Petrochemical Industry Co., Ltd., trade name E-
2605) was added thereto, and the mixture was further held under reduced pressure for 2 hours under vacuum. Then, 180 g of R-134a (trade name: SUVA 134a, manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) was filled. Then, as a compressor continuous mode, the operation was carried out in a thermostatic chamber at 30 ° C., gas was periodically sampled, and moisture analysis was carried out. The results obtained are shown in Table 1.

Comparative Example 1 In the apparatus used in Example 1, the sorption apparatus 3 was replaced by Union Showa KK, trade name Molecular Sieve XH-1.
A dryer filled with 3 was installed. Mineral oil as refrigeration oil (manufactured by Nippon San Oil Co., Ltd., trade name Suniso 3GSD) 18
The operation was performed in the same manner as in Example 1 except that 5 ml and 210 g of R-12 (trade name, manufactured by Showa Denko KK) were charged as the refrigerant. The results obtained are shown in Table 1.

[0033]

[Table 1]

[0034]

In the compression refrigerator of the present invention, the sorbent pack in which the sorbent is coated with the permeable membrane is brought into contact with the refrigerant, so that water in the refrigerant and gas produced by decomposition of the refrigerating machine oil are generated. Can be efficiently removed, refrigeration efficiency can be maintained at a high level, decomposition of the refrigerator can be suppressed, and clogging of capillaries and abrasion of sliding parts due to outflow of sorbent powder can be prevented.

[Brief description of drawings]

FIG. 1 is a system diagram of a compression refrigerator according to an embodiment.

FIG. 2 is a cross-sectional view of a sorption device.

FIG. 3 is a perspective plan view of a sorbent pack.

4 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

 3 Sorption Device 7 Refrigerant Pipe 9, 10 Support 11 Sorbent Pack 12 Sorbent 13 Permeable Membrane 14 Heat Seal Section

Claims (6)

[Claims] 1. A compression type refrigerating machine in which a sorbent is arranged in a refrigerant passage to remove water contained in the refrigerant and a gas produced by decomposition of refrigerating machine oil, A compression type refrigerator characterized in that a sorbent pack coated with a molecularly permeable membrane is brought into contact with a refrigerant. 2. The compression refrigerator according to claim 1, wherein the refrigerant is hydrofluorocarbon. 3. The compression refrigerator according to claim 1, wherein the refrigerator oil is a compound having a carboxylic acid ester bond or a carbonic acid ester bond. 4. The sorbent is one or more selected from alkali metals or alkaline earth metals, oxides or hydroxides thereof, silica gel, molecular sieves, phosphoric anhydride, and liquid bases. The compression refrigerator according to any one of 1. 5. The permeable membrane has polyimide, polyamide, polyacetal, polyester, polycarbonate, polyether, polysulfone, polyethylene, polypropylene, polypropylene copolymer, polybutene-1, poly4.
-Methylpentene, poly-4-methylpentene copolymer,
Butyl rubber, hydrogenated NBR, EPDM, silicone rubber,
The compression refrigerator according to any one of claims 1 to 4, which is a film made of one or more selected from acrylic rubber, fluororubber, and a composite thereof. 6. The compression refrigerator according to claim 1, wherein the compression refrigerator is an electric refrigerator, a room air conditioner or a car air conditioner.