JPH11237140A - Refrigerant pipeline for refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the erosion of the inside of a pipeline and permit the elimination of lock damage of a compressor by a method wherein a high temperature side pipeline, connected to the delivery side of the compressor, and a low temperature side pipeline, laid at the returning side of refrigerant, are arranged by combining copper series metallic pipes and refrigerating machine oil deterioration preventing metallic tubes. SOLUTION: Fundamental structural pipelines among pipelines, connecting a compressor 1, an oil separator 3, a condenser 4, a liquid receiver 5, an expansion valve 6 and an evaporator 7, are connected through stainless steel pipes 9, a high-temperature side pipeline 2 is connected between the compressor 1 and the condenser 4 while a low-temperature side pipeline 8 is connected between the evaporator 7 and the compressor 1. In this case, a copper tube is employed for the high-temperature side pipeline 2 and an aluminum tube is employed for the low-temperature side pipeline 8. According to this method, deposition of metallic copper in the bearing parts of the compressor is reduced, the deterioration of refrigerating oil due to oxidization is reduced, erosion in the refrigerant pipelines for a refrigerating machine can be prevented effectively and, further, the damage of the compressor due to locking can be eliminated completely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant pipe for a refrigerator. More specifically, the present invention relates to refrigerant piping for refrigeration / cooling equipment such as home air conditioners, business air conditioners, automobile air conditioners, home refrigerators, business refrigerators, and the like.

[0002]

2. Description of the Related Art Refrigerating / cooling devices such as air conditioners and refrigerators are provided with pipes for connecting compressors, oil separators, condensers, liquid receivers, expansion valves, evaporators and the like.

[0003] Among these pipes, the basic constituent pipes are connected by stainless steel pipes, but the high-temperature side pipe connected to the refrigerant delivery side of the compressor and the low-temperature side pipe connected to the refrigerant return side are copper-based metal pipes (copper-based pipes). Pipe or copper alloy pipe).

[0004] Refrigerant circulates in these pipes. Further, a lubricating oil for a compressor, which is called a refrigerating machine oil, is dissolved in the refrigerant, so that the refrigerating machine oil-dissolved refrigerant circulates in these pipes.

[0005] The reason why the copper-based metal pipe is connected to the high-temperature side pipe connected to the refrigerant delivery side of the compressor and the low-temperature side pipe connected to the refrigerant return side is that pipe workability, caulking, welding, and so on. This is because workability, thermal conductivity, mechanical strength, durability and the like are excellent.

However, according to recent studies, it has been found that copper-based metal tubes deteriorate refrigerant and refrigerating machine oil when refrigeration / cooling equipment is subjected to severe operation for a long period of time.

That is, a part of the refrigerant or the refrigerating machine oil becomes an acidic or oxidative corrosive substance when it comes into contact with a copper pipe or a copper alloy pipe which has become hot due to severe operation. The corrosive substance generated here corrodes the copper tube or the copper alloy tube. Further, the copper ions generated by this corrosion undergo an electrochemical displacement reaction with the iron bearing of the compressor, and as a result, metallic copper is deposited on the iron bearing. In a compressor in which metallic copper is deposited on an iron bearing, the slidability of a sliding portion deteriorates, and in severe cases, there is a concern that lock damage of the compressor may occur.

Conventionally, the following measures have been taken to prevent such corrosion of copper-based metal tubes.

A. Addition of a conversion agent This method is a method in which a conversion agent capable of neutralizing or reducing a corrosive substance is previously added to a refrigerant oil-soluble refrigerant.

B. Reduce the length of copper or copper alloy pipes
Contraction this method is to reduce the length of the easy copper-based metal tube Copper tube to deteriorate the refrigerant and the refrigerating machine oil as much as possible.

[0011] c. Corrosion-resistant metal plating on the inner wall of a copper-based metal tube This method is a method in which a corrosion-resistant metal plating is applied to a copper-based metal tube or an inner wall of a copper tube that easily deteriorates a refrigerant or a refrigerating machine oil.

[0012] d. The method piping stainless steel tube is a method of piping the stainless steel tube in place of the copper pipe or a copper alloy tube tends to degrade the refrigerant and the refrigerating machine oil.

[0013]

However, the above-mentioned a to
The method d has the following disadvantages.

A. Addition of a converting agent In this method, when the added converting agent is consumed, there is a problem that the corrosive substance increases thereafter.

Here, it is conceivable to add a large amount of the converting agent. However, in this case, there is a problem that the essential properties of the refrigerant and the refrigerating machine oil are remarkably impaired, which is practically impossible.

The conversion agent can be replenished periodically, in which case the refrigerating / cooling equipment is temporarily stopped,
There is a problem that complicated operations such as measurement of the remaining amount of the conversion agent and replenishment of the conversion agent are involved.

B. Reducing the piping length of copper-based metal pipes Even though the piping length of copper-based metal pipes is to be made as short as possible, the piping of refrigeration and cooling equipment was originally designed to be as short as possible. is there.

[0018] c. Corrosion resistant metal plating on the inner wall of the copper-based metal pipe This method requires that the corrosion-resistant metal plating be applied to the inner wall of the copper-based metal pipe so that the exposed portion of the copper is completely eliminated, and that the pipe be considerably thick and over the entire length. There is a disadvantage that the cost increases. In addition, the corrosion-resistant metal-plated tube has a problem that a copper exposed portion is generated due to partial peeling due to welding or bending during piping work, and as a result, deterioration due to the copper exposed portion cannot be prevented.

[0019] d. Stainless steel pipes Stainless steel pipes are inferior in crimpability and welding workability as compared with copper-based metal pipes, and as a result, there is a concern that stainless steel pipes may leak. In addition, there is a problem that the cost of the stainless steel tube is higher than that of the copper-based metal tube.

The present invention has been made in view of such a point, and an object of the present invention is to solve the above-mentioned drawbacks of the prior art, to prevent corrosion in the piping and to eliminate lock damage to the compressor. It is an object of the present invention to provide a refrigerant pipe for a refrigerator that can be used.

[0021]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a refrigerator for connecting a compressor, an oil separator, a condenser, a liquid receiver, an expansion valve, an evaporator and the like of a refrigeration / cooling device. In the refrigerant pipe for use, the high-temperature side pipe connected to the refrigerant delivery side of the compressor and the low-temperature side pipe connected to the refrigerant return side are formed by combining a copper-based metal pipe and a refrigerating machine oil deterioration preventing metal pipe. A refrigerant pipe for a refrigerator.

In the present invention, the refrigerating machine oil deterioration preventing metal pipe is preferably one selected from an aluminum pipe, an aluminum alloy pipe, a magnesium pipe, a magnesium alloy pipe, a zinc pipe, and a zinc alloy pipe.

In the present invention, it is preferable that the high temperature side pipe is made of a copper-based metal pipe and the low temperature side pipe is made of a refrigerating machine oil deterioration preventing metal pipe.

In the present invention, it is preferable that the inner surface area of the metal pipe for preventing deterioration of the refrigerator oil occupies 10 to 95% of the inner surface area of the entire pipe.

Here, the reason why the inner surface area of the refrigerating machine oil deterioration preventing metal pipe is limited so as to occupy 10 to 95% of the inner surface area of the entire pipe is that when it is less than 10%, the effect of preventing deterioration of refrigerant and refrigerating machine oil is small. Conversely, at 95% or more, the effect of preventing deterioration of the refrigerant and the refrigerating machine oil is saturated, and the pipe workability, caulking property, welding workability, heat conductivity,
This is because mechanical strength, durability and the like are completely lost.

The refrigerant pipe for a refrigerator according to the present invention is constituted by a copper-based metal pipe and a metal pipe for preventing deterioration of the refrigerator oil.
The deterioration of the refrigerant and the refrigerating machine oil can be significantly reduced.

Even if the refrigerant and the refrigerating machine oil produce corrosive substances in the copper metal pipe portion, the generated corrosive substances are neutral and non-oxidizing organic in the refrigerating machine oil deterioration preventing metal pipe portion. It can be modified into a substance, and as a result, corrosion of the copper-based metal tube portion can also be effectively suppressed.

The metal pipe for preventing oil deterioration of a refrigerator can effectively capture copper ions generated by corrosion of a copper-based metal pipe portion by an electrochemical substitution reaction. As a result, copper ions generated by corrosion are deposited on an iron bearing. It does not precipitate as metallic copper, thus completely eliminating lock damage of the compressor.

[0029]

Next, an embodiment of a refrigerant pipe for a refrigerator according to the present invention will be described.

FIG. 1 is a block diagram showing an embodiment of a refrigerant pipe for a refrigerator according to the present invention.

In FIG. 1, 1 is a compressor, 2 is a high temperature side pipe (a pipe connecting the compressor 1 and the oil separator 3), 3 is an oil separator, 4 is a condenser, and 5 is a liquid receiver. , 6 is an expansion valve, 7 is an evaporator, 8 is a low temperature side pipe (a pipe connecting between the evaporator 7 and the compressor 1), and 9 is a stainless steel pipe.

As can be seen from FIG. 1, the refrigerant pipe for the refrigerator according to one embodiment of the present invention is provided between the compressor 1, the oil separator 3, the condenser 4, the liquid receiver 5, the expansion valve 6, and the evaporator 7. Consists of connecting pipes.

Of these pipes, the basic constituent pipes have an inner diameter of φ
They are connected by a 6 mm stainless steel tube 9. Compressor 1
A high temperature side pipe 2 is connected between the evaporator 7 and the condenser 4, and a low temperature side pipe 8 is connected between the evaporator 7 and the compressor 1.

Next, the conditions of the examples and comparative examples will be described.

(Conditions of Examples and Comparative Examples) High-temperature side pipes: The pipes used had an inner diameter of 6 mm. The piping material was changed according to the examples and comparative examples.

Low-temperature side pipe: The size of the pipe is the inner diameter φ.
A 6 mm one was used. The piping material was changed according to the examples and comparative examples.

A refrigerant R134a was used.

Refrigerator oil: An ester synthetic oil was used.

Refrigerator oil-soluble refrigerant: The refrigerant oil-soluble refrigerant is a mixture of refrigerant: refrigerant oil = 3: 2.

(Test Methods of Examples and Comparative Examples) Test time: 300 hours Test item: a. Observation of surface condition of copper-based metal tube b. Observation of the state of metal copper deposition on the bearing part of the compressor The results are shown at the copper deposition level. Level 100: The amount of deposited copper that locks the bearing sliding part of the compressor after six months of operation. Level 55: The amount of copper deposition that becomes practically inferior. c. After the test, the total acid value of the refrigerator oil was measured.

(Test Results of Examples and Comparative Examples) In Examples and Comparative Examples, a high-temperature side pipe 2, a low-temperature side pipe 8, a metal pipe for preventing deterioration of a refrigerating machine oil with respect to an inner surface area of a copper-based metal pipe (in the table, Cu), Table 1 shows the internal surface area ratio of the aluminum tube (Al in the table), the metal copper deposition level on the bearing portion of the compressor, and the like.

[0042]

[Table 1]

As can be seen from Table 1, in the pipe of Comparative Example 1, metal copper deposition on the bearing portion of the compressor was level 100.
And there was a big difficulty. The total acid value of the refrigerating machine oil is 5.
It was 0 mg KOH / g of refrigerating machine oil, and it was found that acidic substances had been produced.

Also in the piping of Comparative Example 2, there was a great difficulty that the deposition of metallic copper on the bearing portion of the compressor was level 60. Further, the total acid value was 2.7 mg KOH / g of refrigerating machine oil, and it was found that an acidic substance was generated.

In the pipe of Comparative Example 3, the precipitation of metallic copper on the bearing portion of the compressor was as low as level 3, and the total acid value of the refrigerating machine oil was as excellent as 0.5 mg or less KOH / g of refrigerating machine oil.
However, the inner surface area ratio of the aluminum tube described later is 90%.
Is substantially the same as that of the fourth embodiment. Thus, Comparative Example 3
Even if the inner surface area ratio of the aluminum pipe is 95%, the effect of preventing the deterioration of the refrigerant and the refrigerating machine oil is saturated, and Table 1
Although not shown, there is a disadvantage that the pipe workability, caulking property, welding workability, thermal conductivity, mechanical strength, durability, and the like of the copper-based metal pipe are completely lost.

On the other hand, in the pipes of Examples 1 to 6,
Precipitation of metallic copper on the bearing portion of the compressor is as low as 3 to 20 and the total acid value of the refrigerating machine oil is 0.5 to 0.9 mg KO.
H / refrigerating machine oil g, so that corrosion in the piping can be effectively prevented and lock damage to the compressor can be completely eliminated.

In the first to fourth embodiments, a copper pipe is used for the high-temperature side pipe 2 and an aluminum pipe is used for the low-temperature side pipe 8. On the other hand, in Examples 5 and 6, an aluminum pipe was used for the high-temperature side pipe 2 and a copper pipe was used for the low-temperature side pipe 8.

Comparing the test results between these groups, Examples 1 to 4 in which a copper pipe is used for the high-temperature pipe 2 and an aluminum pipe is used for the low-temperature pipe 8 are superior.

Therefore, it is understood that the aluminum pipe is more preferably used for the low-temperature side pipe 8.

[0050]

According to the refrigerant pipe for a refrigerator of the present invention, the deposition of metallic copper on the bearing portion of the compressor is extremely small, and the oxidation of the refrigerant oil is little deteriorated, so that corrosion in the refrigerant pipe for the refrigerator can be effectively prevented. Further, the lock damage of the compressor can be completely eliminated, and as a result, the reliability of the refrigerating / cooling device provided with the refrigerant pipe for the refrigerator of the present invention can be significantly improved,
It is industrially useful.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a refrigerant pipe for a refrigerator of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Compressor 2 High temperature side piping (Piping which connects between compressor 1 and oil separator 3) 3 Oil separator 4 Condenser 5 Liquid receiver 6 Expansion valve 7 Evaporator 8 Low temperature side piping (Evaporator 7 and (Piping connecting to compressor 1) 9 Stainless steel pipe

Claims (4)

[Claims] 1. A refrigerant pipe for a refrigerator, which connects between a compressor, an oil separator, a condenser, a liquid receiver, an expansion valve, an evaporator and the like of a refrigeration / cooling device, to a refrigerant discharge side of the compressor. A refrigerant pipe for a refrigerator, wherein the high-temperature side pipe to be connected and the low-temperature side pipe to be connected to the refrigerant return side are formed by combining a copper-based metal pipe and a refrigerating machine oil deterioration preventing metal pipe. 2. The refrigerating machine oil deterioration preventing metal pipe is one selected from an aluminum pipe, an aluminum alloy pipe, a magnesium pipe, a magnesium alloy pipe, a zinc pipe, and a zinc alloy pipe. Item 7. A refrigerant pipe for a refrigerator according to Item 1. 3. The refrigerant pipe for a refrigerator according to claim 1, wherein the high-temperature side pipe is formed of a copper-based metal pipe, and the low-temperature side pipe is formed of a refrigerating machine oil deterioration preventing metal pipe. 4. An inner surface area of a metal pipe for preventing deterioration of a refrigerator oil,
2. The refrigerant pipe for a refrigerator according to claim 1, wherein the pipe is constituted so as to occupy 10 to 95% of the inner surface area of the entire pipe.