JP4460941B2 - Heat exchange mechanism with corrosion prevention function - Google Patents

Description

The present invention relates to a heat exchange mechanism having a corrosion prevention function .

  One type of heat exchange mechanism is a heat exchange mechanism (heat exchanger) having a plurality of aluminum fins on the outer periphery of a copper pipe. The heat exchanger performs heat exchange between a heat exchange medium flowing through a copper pipe and outside air or inside air, and is used by being placed inside or outside a refrigerator, outside a freezer, inside an air conditioner, or the like. .

  In the heat exchanger in which such a usage mode is adopted, when exposed to a corrosive gas generated in the refrigerator, or when exposed to a corrosive gas contained in the outside air for a long period of time. The copper pipes and aluminum fins constituting the heat exchanger are gradually corroded. In the heat exchanger, corrosion also occurs due to a potential difference caused by the combination of the copper pipe and the aluminum fin. The occurrence of corrosion of copper pipes and aluminum fins due to these is significant when the heat exchanger is in a humid environment.

  Further, as another form of the heat exchange mechanism, heat provided with a copper pipe for circulating a heat exchange medium and a stainless steel partition wall portion that contacts the outer periphery of the copper pipe and dissipates heat transmitted from the copper pipe. There is an exchange mechanism. The heat exchange mechanism of this type directly cools the refrigerator compartment, freezer compartment, or ice making compartment partitioned by the partition wall, but has the same problem as the heat exchanger described above.

  Therefore, in the heat exchange mechanism of this type, in order to prevent the occurrence of the above-mentioned corrosion, a corrosion inhibitor mainly comprising a resin component is applied to the outer surface of the heat exchange mechanism, and the outer surface of the heat exchange mechanism is applied. Is covered with a resin film. The resin film functions to prevent contact between the outer surface of the heat exchange mechanism and the corrosive gas or moisture to prevent the occurrence of corrosion in the heat exchange mechanism (see Patent Document 1).

However, the resin film formed on the outer surface of the heat exchange mechanism of this type has poor heat conductivity compared to metal, and reduces the heat exchange efficiency in the heat exchange mechanism. For this reason, in the heat exchange mechanism proposed in Patent Document 1 described above, the surface of the resin film is made uneven to prevent a decrease in heat exchange efficiency in the heat exchange mechanism, and furthermore, fine particles such as metal Means for adhering are also taken. Further, the resin film formed by the corrosion inhibitor used in the invention described in Patent Document 1 described above cannot be said to have a sufficient corrosion prevention effect in a severe corrosive gas atmosphere.
JP 58-136995 A

  As described above, as a countermeasure for preventing corrosion of the heat exchange mechanism of this type, basically, a corrosion inhibitor mainly including a resin component is applied to the outer surface of the heat exchange mechanism to A means for forming a resin film on the surface is employed, thereby obtaining the effect of preventing the occurrence of corrosion in the heat exchange mechanism.

  By the way, the most important thing when taking the corrosion prevention measures is to select the type of the corrosion inhibitor and to prevent the heat exchange efficiency in the heat exchange mechanism from being lowered. The corrosion inhibitor currently used is a resin coating mainly composed of a polyester resin or a polyacrylic resin.

  In the resin film formed by these resin coatings, when condensed water in which a corrosive gas such as hydrogen sulfide gas or acetic acid gas dissolves penetrates into the resin film, specific molecular bonding sites in the resin forming the resin film are present. Deteriorated due to damage such as being cut. As a result, the resin film is locally broken or the resin film is peeled off from the outer surface of the heat exchange mechanism, and the contact blocking function against corrosive gas and moisture on the outer surface of the heat exchange mechanism is impaired.

  In addition, in the case of conventional corrosion inhibitors mainly composed of resin components, it is important to prevent a decrease in heat exchange efficiency in the heat exchange mechanism apart from the problem of selection. In addition to the means for applying a corrosion inhibitor on the surface and forming a resin film on the outer surface, it is necessary to take some means for preventing a decrease in heat exchange efficiency.

Therefore, the object of the present invention is that the resin film formed on the outer surface of the heat exchange mechanism is not easily deteriorated even by condensed water that dissolves corrosive gas, and the heat exchange efficiency in the heat exchange mechanism is greatly reduced. It is an object of the present invention to provide a heat exchange mechanism having a corrosion prevention function that can be suppressed.

The present invention relates to a heat exchange mechanism having a corrosion prevention function . The heat exchange mechanism to which the present invention is applied is made of a different metal from the copper pipe that circulates the heat exchange medium and the copper pipe that contacts the copper pipe and dissipates heat transmitted from the copper pipe. A heat dissipating member is provided, and the copper pipe and the heat dissipating member are coated with a corrosion-preventing film, and an atmosphere exposed to corrosive gas is formed inside / outside the refrigerator, outside the freezer, ice making mechanism It is a heat exchange mechanism provided with a corrosion prevention function of the type installed in the mechanism of the above or in the apparatus of the air conditioner .

Thus, in the heat exchange mechanism having a corrosion prevention function according to the present invention, the corrosion prevention film is mainly composed of a phenol-modified epoxy resin paint , benzotriazole, and aluminum powder , and the aluminum powder together with benzotriazole It is formed by a corrosion inhibitor mixed in the phenol-modified epoxy resin paint .

In the heat exchange mechanism having a corrosion prevention function according to the present invention, a corrosion inhibitor containing an acetylacetone metal salt that functions as a surfactant can be employed as the corrosion inhibitor that forms the corrosion prevention film. .

Further, in the heat exchange mechanism having a corrosion prevention function according to the present invention, a copper pipe that circulates the heat exchange medium, and a plurality of aluminum that is provided on the outer periphery of the copper pipe and dissipates heat transmitted from the copper pipe. A heat exchange mechanism having a structure including fins can be employed.

Further, in the heat exchange mechanism having a corrosion prevention function according to the present invention, a copper pipe that circulates the heat exchange medium, and a stainless steel that dissipates heat transmitted from the copper pipe in contact with the outer periphery of the copper pipe. A heat exchange mechanism having a configuration including a partition wall can be employed.

The corrosion prevention film for coating the outer surface of the heat exchange mechanism having a corrosion prevention function according to the present invention comprises a phenol-modified epoxy resin paint, benzotriazole, and aluminum powder as main components, and the aluminum powder together with benzotriazole is the phenol. It is formed with a corrosion inhibitor mixed in the modified epoxy resin paint. For this reason, in the resin film, the phenol-modified epoxy resin film blocks the contact of corrosive gas and moisture with the outer surface of the heat exchange mechanism, and in particular, aluminum powder mixed in the resin film of the phenol-modified epoxy resin. It functions to prevent the intrusion of condensed water, etc., in which corrosive components are dissolved, into the resin film.

In the corrosion-preventing film , the phenol-modified epoxy resin also functions as a binder for holding the aluminum powder in an aligned state, but the main chain of the molecular structure of the phenol-modified epoxy resin is mainly an ether bond, and an ester bond. Not included. The ether bond is superior in water resistance and chemical resistance compared to the ester bond, and depending on the corrosive component of the corrosive gas such as hydrogen sulfide gas and acetic acid gas, the bond of the molecular bond is damaged. There are few things.

In addition, in the corrosion prevention film, it is recognized that the aluminum powder innumerably mixed in the resin film functions as a sacrificial anode electrically with respect to the copper pipe, and the condensed water and the like have entered the resin film. However, it is recognized that corrosion of copper pipes can be prevented. In addition, the corrosion-preventing film contains benzotriazole in particular. Since benzotriazole is an extremely effective chemical substance for preventing corrosion of copper pipes, it has a further effect of preventing corrosion.

As described above, in the heat exchange mechanism having a corrosion prevention function according to the present invention, the corrosion prevention film covering the outer surface of course blocks the contact of corrosive gas and moisture with the outer surface of the heat exchange mechanism. However, it prevents the penetration and penetration of the aqueous solution in which the corrosive component of the corrosive gas is dissolved, thereby preventing local destruction of the resin film and peeling of the resin film. In addition to this function, the aluminum powder functions to increase the heat conduction of the resin film, which greatly reduces the heat exchange efficiency in the heat exchange mechanism due to the corrosion prevention film formed on the outer surface of the heat exchange mechanism. Can be suppressed.

The present invention relates to a heat exchange mechanism having a corrosion prevention function, in which an outer surface is coated with a corrosion prevention film. The heat exchange mechanism according to the present invention includes a copper pipe that circulates a heat exchange medium, and a metal heat radiating member that is different from the copper pipe that contacts the copper pipe and dissipates heat transmitted from the copper pipe. a heat exchanger structure comprising, the refrigerator inside and outside the atmosphere to be exposed to corrosive gases are formed, the refrigerator outside the freezer, the mechanism of the ice-making mechanism, or heat exchange system to be installed in the apparatus of the air conditioner It is.

FIG. 1 shows a refrigeration circuit having a heat exchanger which is an embodiment of the heat exchange mechanism according to the present invention. FIG. 2 shows the heat exchanger in an enlarged manner. The heat exchanger is disposed in the refrigerator circuit, for example, as a cooler in the refrigerator, and functions to cool the air in the refrigerator by exchanging heat in the refrigerator. .

  The refrigeration circuit 10 includes a compressor 12 that compresses a refrigerant, a condenser 13 that condenses the refrigerant compressed by the compressor 12, and a refrigerant that is condensed by the condenser 13 in a circulation line 11 of a cooling medium (refrigerant). The heat exchanger 20 is interposed in the circulation line 11 of the refrigeration circuit 10.

  As shown in FIG. 2, the heat exchanger 20 is composed of a plurality of copper pipes 21 and a number of aluminum fins 22. Each copper pipe 21 is brazed with a copper U-shaped vent 23. The refrigerant pipes are connected to each other and bent several times. Each aluminum fin 22 is fixed to the outer periphery of each copper pipe 21 by expanding each copper pipe 21 radially outward in a state of passing through each copper pipe 21. The heat exchanger 20 is disposed in the upper part of the refrigerator as a cooler, and performs heat exchange between the air in the refrigerator and the refrigerant flowing through the copper pipes 21 to cool the air in the refrigerator. Thus, the air is cooled at a predetermined temperature.

  The heat exchanger 20 is always exposed to various corrosive gases generated from food and food stored in the refrigerator when the refrigerator is disposed in the refrigerator. For example, a corrosive gas containing sulfur such as hydrogen sulfide is generated from boiled eggs or fried eggs, and a corrosive gas including acetic acid such as acetic acid gas is generated from vinegar, bread dough or mayonnaise.

  Also, in refrigerators and freezers installed in an environment where corrosive gas is generated, for example, corrosive gas such as hydrogen sulfide generated from a hot spring source such as sulfur springs enters the warehouse, In a refrigerator, a freezer, or the like installed near a vinegar factory or in the same place, there is a risk that acetic acid gas may enter the cabinet. For this reason, the said heat exchanger 20 installed in the store | warehouse | chamber is exposed to these corrosive gas which penetrate | invades in the store | warehouse | chamber. In the type in which the heat exchanger 20 is installed outside the main body, the heat exchanger 20 is directly exposed to the outside air containing corrosive gas.

In the heat exchanger 20, as described above, when exposed to various corrosive gases, the occurrence of corrosion is gradually promoted and the life is shortened. Therefore, each copper pipe 21 that is the outer periphery of the heat exchanger 20 is used. In addition, a means for applying a resin paint as a corrosion inhibitor to the surface of each aluminum fin 22 to form a resin film on the outer surface of the heat exchanger 20 is employed. The resin film is a corrosion prevention film, and functions to block contact of the internal air and the external air with the outer surface of the heat exchanger 20. Thereby, the early corrosion of the said heat exchanger 20 can be prevented, and a useful life is improved.

The anti-corrosion measure for the heat exchanger 20 is basically a means for applying a corrosion inhibitor mainly comprising a resin component to the outer surface of the heat exchanger 20 and forming a resin film on the outer surface. In the present invention, the resin film is defined as a corrosion prevention film. Conventionally, a corrosion inhibitor mainly comprising a polyester resin paint or a polyacrylic resin paint has been employed. The resin film formed by the corrosion inhibitor has a problem that the durability against the corrosive gas to be exposed is inferior, and the resin film has a problem that the heat exchange efficiency of the heat exchanger is lowered. In the present invention, as the corrosion inhibitor, the most suitable corrosion inhibitor for the corrosion prevention of the heat exchanger 20 installed in the atmosphere of the corrosive gas is selected, and the corrosion prevention of the heat exchanger 20 is selected. It is something to deal with.

In the anti-corrosion measures in the present invention, a usage mode in which the selected optimum corrosion inhibitor is applied to the outer periphery of the heat exchanger 20 is adopted, and the corrosion inhibitor is applied to the outer surface of the heat exchanger 20. A resin film, which is a corrosion prevention film, is formed on the outer surface of the heat exchanger 20. FIG. 4 schematically shows a resin film formed by the optimum corrosion inhibitor selected in the present invention. FIG. 5 schematically shows a resin film formed by a conventionally employed corrosion inhibitor. The configuration, characteristics, functions and the like of these resin films will be described later.

  FIG. 3 shows a cooling mechanism that is another embodiment of the heat exchange mechanism that is the subject of the present invention to prevent corrosion. FIG. 3 shows a part of the cross section of the wall portion constituting the refrigerator, and the cooling mechanism portion 30 is configured in the wall portion. The wall portion is formed in a space formed by the stainless steel exterior plate 31 and the interior plate 32, the copper pipe 33, the exterior plate 31 and the interior plate 32 that are spirally disposed in contact with the back surface of the interior plate 32. It is comprised with the heat insulating materials 34, such as filled urethane foam. The cooling mechanism 30 is constituted by a copper pipe 33 and a stainless steel interior plate 32.

In the cooling mechanism 30, a cooling medium is introduced into the copper pipe 33 and circulates and flows. During this time, the heat of the cooling medium is transferred from the copper pipe 33 to the interior plate 32, and the refrigerator is refrigerated via the interior plate 32. Cool the room. In the cooling mechanism 30, a means for applying a corrosion inhibitor having a resin component as a main component to the outer surface of the copper pipe 33 and forming a resin film 33 a on the outer surface is employed. In the cooling mechanism section 30, a corrosion inhibitor may be applied also to the back side of the interior plate 32 with which the copper pipe 33 contacts. As the corrosion inhibitor, the optimum corrosion inhibitor selected in the present invention is employed.

The optimum corrosion inhibitor selected in the present invention is mainly composed of phenol-modified epoxy resin paint, benzotriazole, and aluminum flakes, and aluminum powder together with benzotriazole is innumerable in phenol-modified epoxy resin paint. It is a mixture.

An example of the corrosion inhibitor selected in the present invention includes 70 to 80 parts of an epoxy resin as a main agent, 20 to 30 parts of a phenol resin as a curing agent, 10 to 30 parts of aluminum powder , and 0.1 to 1 of benzotriazole. It is a one-component heat-curing anticorrosive paint having a composition of 5 parts , and preferably, 0.1 to 1.5 parts of an acetylacetone metal salt functioning as a surfactant is added to the blend of these components Is.

As the phenol-modified epoxy resin paint which is one component of the corrosion inhibitor , for example, a phenol-modified epoxy resin clear (Olga 1000H clear: manufactured by Nippon Paint Co., Ltd.) which does not contain a pigment can be suitably employed. The aluminum powder which is one component in the corrosion inhibitor preferably has an average particle diameter of several μm to several tens of μm, for example, flaky aluminum having an average particle diameter of 5 μm (Al-S NO. 22000: Yamato Metal). Flour Industries Co., Ltd.) and flaky aluminum having an average particle size of 33 μm (Al-S NO. 600: manufactured by Yamato Metal Powder Industries Co., Ltd.) can be suitably employed.

FIGS. 4 (a) shows the resin film 20a that optimum corrosion inhibitors selected in the present invention is formed on the outer surface of the base of the heat exchanger 20, FIG. (B) is conventionally The resin film 20b which the corrosion inhibitor currently used forms in the outer surface of the base material of the heat exchanger 20 is shown. The resin film 20a is formed by a resin layer a1 mainly composed of a phenol-modified epoxy resin paint and an infinite number of aluminum powders (aluminum flake group a2) as one component arranged in the resin layer a1. It is. In contrast, the resin film 20b is formed only of the resin layer b mainly composed of a phenol-modified epoxy resin clear, which is a conventional corrosion inhibitor. In the usage mode of each corrosion inhibitor according to the present invention, the resin film 20 a covers the entire outer surface of the heat exchanger 20.

In the heat exchanger 20 of one embodiment according to the present invention, a resin film 20a is formed on the outer surface thereof. In the resin film 20a, the resin layer a1 functions to block the contact of corrosive gas and moisture with the outer surface of the heat exchanger 20, and the countless aluminum flakes a2 arranged in the resin layer a1 are corroded. It functions to prevent intrusion into the resin layer a1 of condensed water or the like that dissolves the corrosive component of the reactive gas. It is recognized that the countless aluminum flake group a2 functions as a sacrificial anode for the copper pipe 21 constituting the heat exchanger 20. For this reason, even if the condensed water containing a corrosive component enters the resin layer a1, the occurrence of corrosion of the copper pipe 21 is prevented.

  In the resin coating 20a, the resin coating forming the resin layer a1 also functions as a binder for holding the aluminum flake group a2 in an arrayed state. However, in the resin coating, in the main chain of the molecular structure. There is no ester bond, and there is an ether bond instead. The ether bond in the main chain of the molecular structure is superior in water resistance and chemical resistance compared to the ester bond, and the site of the molecular bond is cleaved by the corrosive component of corrosive gas such as hydrogen sulfide gas and acetic acid gas. There is little damage such as.

  Accordingly, the resin film 20a naturally blocks the contact of the corrosive gas and moisture with the outer surface of the heat exchanger 20, but prevents the penetration and penetration of the aqueous solution in which the corrosive component of the corrosive gas is dissolved. Inhibiting, the local destruction of the resin film 20a and the peeling of the resin film 20a from the outer surface of the heat exchanger 20 are prevented.

  In the resin film 20a, in addition to this function, the countless aluminum flake group a2 functions as a pseudo electrode to prevent the occurrence of corrosion due to the potential difference of the aluminum fins 22, and to conduct the heat conduction of the resin film 20a. It functions to increase and greatly prevents a decrease in heat exchange efficiency in the heat exchanger 20 resulting from the formation of the resin film 20a on the outer surface of the heat exchanger 20.

In the resin film 20a formed by the corrosion inhibitor employed in the present invention , the resin layer a1 contains benzotriazole, which is extremely effective for preventing corrosion of the copper pipe 21, as the third component. A further corrosion prevention effect for the heat exchanger 20 will be exhibited.

The description of the function of the corrosion inhibitor employed in the present invention described above applies to the heat exchanger 20 which is one form of the heat exchange mechanism, but the corrosion inhibitor employed in the present invention is a heat exchanger. A resin film similar to the resin film 20a is formed on the cooling mechanism 30 which is another embodiment of the mechanism, and the same effects are obtained.

In this example, an experiment using the corrosion inhibitor defined in the present invention (Example) and an experiment using the same type of corrosion inhibitor similar to the corrosion inhibitor defined in the present invention (Example) Comparative Examples) and experiments (comparative examples) using conventional corrosion inhibitors that are generally used were tried, and their corrosion prevention effects were confirmed. In each experiment, a heat exchanger 20 in which the entire outer surface is covered with a resin film (20a1... Example, 20a2... Comparative example, 20b... Comparative example) of each corrosion inhibitor (test agent) is used as a refrigerator. The cooling operation of the refrigerator is performed for a long time in an air atmosphere containing a corrosive gas of a predetermined concentration, and the corrosion state of the heat exchanger 20 during the cooling operation, The gas leakage was confirmed. The obtained results are shown in Table 1.

(Test agent): Test agent 1 is of the same type as that of the corrosion inhibitor defined in the present invention , and is a baking type mainly composed of 70 wt% phenol-modified epoxy resin paint and 30 wt% aluminum flakes. It is a paint and contains 1.5 wt% of acetylacetone metal salt.

Specimen 2 corresponds to the corrosion inhibitor defined in the present invention , and is a baking type paint mainly composed of 70 wt% phenol-modified epoxy resin paint, 30 wt% aluminum powder, and 1 wt% benzotriazole. In this, 1.5 wt% of acetylacetone metal salt is contained.

  The test agent 3 is a baking-type paint that has been used in the past, with a phenol-modified epoxy resin clear as a main constituent.

  The phenol-modified epoxy resin paint in each of the test agents 1 and 2 is “Olga 1000H Clear” manufactured by Nippon Paint Co., Ltd., having an epoxy resin varnish of 60.5 wt%, an epoxy-soluble phenol resin varnish of 31.7 wt%, and a solvent 7 .6 wt% and additive 0.2 wt%. Moreover, a solvent is a mixed solvent which consists of toluene (15-20 wt%), n-butyl alcohol (5-10 wt%), isobutyl alcohol (5-10 wt%), and diacetone alcohol (15-20 wt%).

  The aluminum powder in each of the test agents 1 and 2 is an aluminum powder (Al-S NO. 22000) manufactured by Daiwa Metal Powder Industry Co., Ltd. The aluminum powder is aluminum flakes having a flake shape with an average particle diameter of about 5 μm with a purity of composition of Al 99.3 wt%, (Fe + Si) 0.7 wt%, Cu 0.1 wt%, (Mn + Mg + Zn) 0.15 wt%. . In addition, it may replace with the said aluminum powder and may employ | adopt the aluminum powder (Al-S NO.600) by Yamato Metal Powder Industry Co., Ltd. The aluminum powder is aluminum flakes having a scale shape with an average particle diameter of about 33 μm.

Further, the acetylacetone metal salt in each of the test agents 1 and 2 is Al (C ₅ H ₇ O ₂ ) ₃ , which is nursem aluminum manufactured by Nippon Chemical Industry Co., Ltd. The acetylacetone metal salt is added in an amount of about 5.5 wt% of the aluminum powder in order to stabilize the dispersion state of the aluminum powder. In addition, you may reduce the addition amount of the said acetylacetone metal salt to about 1.0 wt%, for example.

(Formation of resin film): The resin film is formed on the outer surface of the heat exchanger 20 by applying the corresponding test agent on the outer surface of each heat exchanger 20 and baking means (20 at 180 ° C.). Minutes). The resin film formed with the test agent 1 is the resin film 20a1 (Example) , the resin film formed with the test agent 2 is the resin film 20a2 (Comparative example) , and the test agent 3 The resin film thus formed is referred to as a resin film 20b (comparative example) . The film thickness of each resin film 20a1, 20a2, 20b was in the range of 30-50 μm.

  (Operating conditions of the refrigerator): Using each heat exchanger 20 having the resin films 20a1, 20a2, and 20b formed on the outer surface as coolers, preparing each refrigerator, the refrigerator is provided in the refrigerator. Was formed in a corrosive gas atmosphere (hydrogen sulfide concentration of about 6 ppm + acetic acid concentration of about 1 ppm), and each refrigerator was cooled for a long period of time.

  To form an atmosphere of corrosive gas (hydrogen sulfide gas + acetic acid gas), each beaker containing the following two types of aqueous solutions that are corrosive gas generation sources is used, and both beakers are stored in the same refrigerator. Stored at the same time. However, both beakers were replaced with beakers containing new aqueous solutions every 200 hours of operation. In addition, in order to hold | maintain the inside of a store | chamber in moderate humidity, the beaker which accommodates 100g of water was accommodated in the store | warehouse | chamber together with both above-mentioned beakers.

  Hydrogen sulfide gas is assumed to be corrosive gas generated from boiled eggs, sulfur springs, etc., in an aqueous solution in which 24 g of sodium sulfide is dissolved in 100 g of water in a 500 mL beaker and sodium sulfide is completely dissolved. Then, 5.44 g of potassium dihydrogen phosphate was dissolved to form a hydrogen sulfide gas generation source. A beaker containing the aqueous solution is used as a hydrogen sulfide gas generation source.

  Acetic acid gas was assumed to be corrosive gas generated from vinegar, bread dough, mayonnaise, etc., and 10 g of glacial acetic acid was completely dissolved in 90 g of water in a 500 mL beaker to form a source of acetic acid gas. A beaker containing the aqueous solution is used as an acetic acid gas generation source.

  (Test items in the experiment): The test items in each experiment were confirmed by confirming the corrosion state by observing the appearance of the heat exchanger 20, confirming the period during which the heat exchanger 20 was poorly cooled, and causing the heat exchanger 20 to leak gas. Three items for confirmation of the period to be reached.

  Appearance observation of the heat exchanger 20 was determined by taking photographs of the heat exchangers on the 16th, 44th, and 203th days before the cooling operation of the refrigerator and on the 16th, 44th, and 203th days after the start of the cooling operation. Confirmation of the cooling failure of the heat exchanger 20 was determined based on the temperature detection in the cooler and the refrigerator. Confirmation of gas leakage of the heat exchanger 20 was confirmed by visually applying nitrogen gas having a gas pressure of 1 MPa to the inside of the heat exchanger 20 coated with the check solution. In the cooling operation of the refrigerator of this experiment, the cooling operation of the refrigerator in which cooling failure or gas leakage was confirmed in the heat exchanger 20 was stopped when these were confirmed.

  (Experimental result): In the cooling operation of the refrigerator, since the inside of the refrigerator was in a severe corrosive gas atmosphere, the occurrence of corrosion was confirmed in each heat exchanger 20. Corrosion was confirmed based on the presence or absence of black and greenish blue deposits produced by the occurrence of corrosion and the amount of deposits produced. Corrosion occurs in the return bend section and defrost heater section on the tip side, and the corrosion site gradually spreads to the adjacent return bend section, and gradually spreads in the defrost heater section. It expands to all parts of the return bend and defrost heater.

In the cooling operation of the refrigerator, the tendency of the occurrence of corrosion in each heat exchanger 20 is substantially the same, but the difference in the degree of corrosion corresponding to the number of days of the cooling operation is recognized in each heat exchanger 20. In the heat exchanger 20 having the resin film 20a1 formed by the inhibitor similar to the corrosion inhibitor defined in the present invention and the resin film 20a2 formed by the corrosion inhibitor defined in the present invention , the conventional heat exchanger 20 It was confirmed that the degree of corrosion was lower than that of the heat exchanger 20 having the formed resin film 20b. Further, the degree of corrosion between the resin coating 20a2 formed by the corrosion inhibitor defined in the present invention and the resin coating 20a1 formed by the inhibitor similar to the corrosion inhibitor defined in the present invention is the former. Was confirmed to be even lower. Table 1 shows the evaluation of the obtained results.

  However, the evaluation is performed in four stages, ◎, ○, △, and ×, where ◎ is the state where no corrosion is observed, and the occurrence of corrosion is recognized, but it is local and the degree of local corrosion is low. The state is ◯, the state of corrosion that has reached the whole, the degree of overall corrosion is medium, and the state that can be assumed to be immediately before gas leakage from the heat exchanger 20 is △, and the state of corrosion is overall A state where it was assumed that the gas was leaked from the heat exchanger 20 was high because the degree of corrosion was high and the overall corrosion was high.

   Regarding the cooling failure of the heat exchanger 20, the heat exchanger 20 having the resin film 20a1 is recognized on the 203th day after the start of the cooling operation, and the heat exchanger 20 having the resin film 20b is on the 44th day after the start of the cooling operation. Recognized by Further, in the heat exchanger 20 having the resin film 20a2, no cooling failure was observed even on the 203rd day after the start of the cooling operation. These results almost coincide with the confirmation results of the occurrence of corrosion shown in Table 1.

  Gas leakage from the heat exchanger 20 is recognized on the 203th day after the start of the cooling operation in the heat exchanger 20 having the resin film 20a1, and the 44th day after the start of the cooling operation in the heat exchanger 20 having the resin film 20b. Recognized by Further, in the heat exchanger 20 having the resin film 20a2, no cooling failure was observed even on the 203rd day after the start of the cooling operation. These results also almost coincide with the confirmation results of the occurrence of corrosion shown in Table 1.

This onset Akira is a schematic configuration diagram illustrating a refrigeration circuit provided with a heat exchanger which is an example of a heat exchange system as a target of anti-corrosion. It is a front view which shows the same heat exchanger. This onset Akira is a partial cross-sectional view of a refrigerator of the wall which have a more cooling mechanism, which is an example of a heat exchange system as a target of anti-corrosion. FIG. 3 is a schematic diagram showing a resin film formed by a corrosion inhibitor defined in the present invention and a corrosion inhibitor similar thereto . It is a schematic diagram which shows the resin film which the conventional corrosion inhibitor forms.

DESCRIPTION OF SYMBOLS 10 ... Refrigeration circuit, 11 ... Circulation line, 12 ... Compressor, 13 ... Condenser, 14 ... Depressurizer, 20 ... Heat exchanger, 21 ... Copper pipe, 22 ... Aluminum fin, 23 ... Vent, 20a ... Resin Coating, a1 ... resin layer, a2 ... aluminum flake group, 20b ... resin coating, b ... resin layer, 30 ... cooling mechanism, 31 ... exterior plate, 32 ... interior plate, 33 ... copper pipe, 33a ... resin layer, 34 ... insulation.

Claims (4)

The copper pipe that circulates the heat exchange medium and the copper pipe that contacts the copper pipe and dissipates the heat transmitted from the copper pipe include a metal heat dissipating member that is different from the copper pipe, and the copper pipe and the heat dissipation the outer surface of the member is covered with a corrosion prevention coating, the refrigerator inside and outside the atmosphere to be exposed to corrosive gases are formed, the refrigerator outside the freezer, the mechanism of the ice-making mechanism, or, in the apparatus of the air conditioner It is a heat exchange mechanism having a corrosion prevention function that is installed, and the corrosion prevention film comprises phenol-modified epoxy resin paint , benzotriazole, and aluminum powder as main components, and the aluminum powder together with benzotriazole is the phenol-modified epoxy resin. heat exchange with the corrosion prevention function, characterized in that it is formed by corrosion inhibitors are mixed in the paint Structure. A heat exchange mechanism having a corrosion prevention function according to claim 1, wherein the corrosion inhibitor forming the corrosion prevention film contains an acetylacetone metal salt that functions as a surfactant. Heat exchange mechanism with functions. A heat exchange mechanism having a corrosion prevention function according to claim 1 , wherein the heat exchange mechanism is provided on a copper pipe through which a heat exchange medium is circulated, and is provided on an outer periphery of the copper pipe and transmitted from the copper pipe. A heat exchange mechanism comprising a plurality of aluminum fins that dissipate heat. It is a heat exchange mechanism provided with the corrosion prevention function according to any one of claims 1 to 3 , wherein the heat exchange mechanism is in contact with a copper pipe through which a heat exchange medium flows and an outer periphery of the copper pipe. A heat exchange mechanism having a corrosion prevention function, comprising a partition wall made of stainless steel that dissipates heat transmitted from a copper pipe.

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