JPH04366395A - Heat exchanger and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve hydrophilic properties of a surface film of a heat exchanger of an evaporator, etc., and to prevent occurrence of cracks and offensive odor. CONSTITUTION:An inorganic series hydrophilic film 12 to be formed on an outer surface of a tube 1, a fin 2 of an evaporator E, is formed of a polymer silica film containing polymer silica 11 as a main ingredient, water dispersive polyamide series resin (or water dispersive polyamine series resin) 9 and antibacterial reagent 10. The contents are, for example, 60-80wt.% the silica 11, 10-40wt.% the polyamide series resin 9, and 3-10wt.% the reagent 10. When the film 12 is provided in the evaporator E, its hydro-extraction is conducted by increasing an air flow speed distribution more toward downward by an air blow, and conducted while inclining the evaporator E at least in one of longitudinal and lateral directions.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger used in an evaporator of a refrigeration cycle, such as an air conditioner for an automobile, and a method for manufacturing the same.

0002

[Prior Art] Conventionally, aluminum heat exchangers (aluminum in this specification includes aluminum alloys)
A surface treatment is performed on the surface for the purpose of preventing white rust due to corrosion, and the surface treatment includes chromate conversion treatment and the like.

[0003] Also, among heat exchangers, in evaporators,
Since condensed water is generated on the surface, water droplets accumulate between the fins, increasing ventilation resistance and easily causing performance deterioration. There was a problem in that microorganisms (hereinafter collectively referred to as "microorganisms") were likely to occur, and that the microorganisms generated off-flavors.

Among the above problems, regarding the problem of condensed water, it may be considered to form a film of an inorganic substance such as silica on the chemical conversion film in order to improve hydrophilicity. However, in general, inorganic substances, especially polymeric silica, are easily detached from the film and are scattered as fine powder, which tends to lead to a decrease in hydrophilic performance.
Furthermore, there is a problem in that the scattered particles stimulate the user's sense of smell and give off an unpleasant odor.

[0005] Therefore, as described in JP-A-60-50397 and JP-A-61-250495, in order to improve antibacterial and hydrophilic properties, the outer surface of the heat exchanger was coated with
Surface treatment techniques have been proposed that form organic polymer resin films based on organic polymer resins (for example, water-soluble polyamide resins) containing polymer silica and antibacterial agents.

Examples of antibacterial agents include 2-(4-thiazolyl)-benzimidazole, N-(fluorodichloromethylthio)-phthalimide, and N-dimethyl-N'-phenol-N'-(fluorodichloromethylthio). )-sulfamide, 10-10'-oxybisphenoxyarsine, etc. are used.

[0007]

[Problem to be solved by the invention] Among the above conventional techniques,
When a film based on an organic polymer resin is used as the film formed on the outer surface of the heat exchanger, the organic polymer resin is generally water-repellent [even if it has hydroxyl groups that have good affinity with water]. Even if a water-soluble (water-dispersible) resin is used, this is a problem limited to the resin; it is essentially water-repellent), and its hydrophilicity is lower than that of silica or the like.

Furthermore, when the content of the organic polymer resin exceeds 50% by weight, the properties of the surface treatment liquid change and the viscosity of the surface treatment liquid increases rapidly, causing the surface treatment liquid that adheres to the heat exchanger surface to deteriorate. The amount increases, and the surface treatment film becomes thicker. The surface of a heat exchanger, especially the surface of a heat exchanger manufactured by a brazing method using flux, is a very porous surface, and if the surface treatment film exceeds a certain thickness, the surface treatment film will deteriorate. cracks are more likely to occur.

[0009] Normally, a heat exchanger is used in such a manner that there is a large temperature difference between when it is in operation and when it is stopped, and the heat exchanger repeats a cooling/heating cycle. Therefore, if a crack occurs in the surface treatment film, it will fall off and scatter due to the cooling/heating cycle, resulting in a decrease in hydrophilic and antibacterial performance, and the scattered particles will irritate the user's sense of smell and cause unpleasant odor. .

Furthermore, when the viscosity of the surface treatment liquid increases,
A film of organic polymer resin may be formed between the fins, increasing ventilation resistance and deteriorating performance. Furthermore, organic polymer resins have the property of expelling impurities contained therein (hereinafter referred to as bleed-out); for example, agents (antibacterial agents) for mold, bacteria, etc. If mixed, there was a problem that the antibacterial agent would bleed out.

The present invention has been made in view of the above points, and its objects are to improve the performance of a heat exchanger by improving hydrophilicity, preventing the proliferation of microorganisms, and effectively preventing detachment and scattering of the surface treatment film itself. The objective is to prevent the deterioration and suppress the occurrence of strange odors.

0012

[Means for Solving the Problems] In order to achieve the above object, the present invention basically proposes the following means for solving the problems.

One is a heat exchanger comprising tubes and fins through which a refrigerant flows, and the outer surface (hereinafter simply referred to as the surface) of this heat exchanger is coated with water-dispersible polymer silica as a main component. We propose a heat exchanger coated with a polymeric silica film containing at least one type of resin, polyamide resin and water-dispersible polyamine resin, and an agent (antibacterial agent) that prevents the growth of mold and bacteria. . (These are the first means of solving the problem).

[0014] The other problem is regarding the method for manufacturing a heat exchanger. In the surface treatment process of the heat exchanger, the heat exchanger made of tubes, fins, etc. is immersed in a surface treatment liquid, and then the liquid is drained and dried. An air blowing method is used to blow air onto the heat exchanger, and the air blowing speed is set at a blowing position where the wind speed blowing at the bottom of the heat exchanger is set higher than the wind speed blowing onto other parts. We propose a so-called wind speed distribution change method (
This will be the second problem-solving method).

[0015] Another method of manufacturing a heat exchanger is to propose a method in which the liquid draining using the air blow method is performed while tilting the heat exchanger in at least one direction of the front and back or left and right directions (this is the third problem). as a solution).

[0016]

[Effect]

[Operation of the first problem-solving means] (a) Considering only hydrophilic performance, the film on the surface of the heat exchanger is made of polymeric silica 1
00% by weight is the best, but as mentioned above, if the film is made only of silica, the silica particles will separate from the film and scatter as fine powder, causing durability problems such as deterioration of hydrophilic performance over time. There are also problems with odor generation.

On the other hand, as in the present invention, the film on the surface of the heat exchanger is made of polymer silica as the main component (base).
When at least one type of water-dispersible polyamide resin and water-dispersible polyamine resin (hereinafter collectively referred to as water-dispersible polyamide resin, etc.) is contained as , fixes the antibacterial agent and suppresses desorption and scattering of the above-mentioned polymer silica and antibacterial agent, which are components of the surface treatment film.

[0018] Furthermore, even if the above-mentioned polymeric silica and antibacterial agent are likely to detach or scatter from the surface treatment film in the worst case, water-dispersible polyamide resins etc. have the property of being slightly soluble in water, and the surface Components that are likely to be desorbed or scattered from the treated film are washed away together with condensed water, thus preventing components such as silica from being desorbed or scattered from the dry surface treatment film.

[0019] When the base of the film formed on the surface of the heat exchanger is polymer silica as in the present invention, it is much more hydrophilic than when it is based on organic polymer resin as in the past. Significantly improve performance.

[0020] When polymeric silica is used as a base and contains a water-dispersible polyamide resin or the like, the hydrophilicity decreases compared to 100% by weight of silica, but this decrease is within a range that does not cause any practical problems. It is.

In addition, although water-dispersible polyamide resins are inferior in hydrophilicity to silica, they have hydroxyl groups that have good affinity with water, so they are superior to other organic polymer resins at the level of organic polymer resins. In comparison, it has an order of magnitude greater affinity for water, and in that sense, it can be said that among the means for fixing polymeric silica and antibacterial agents, it has the ability to minimize the decrease in hydrophilicity.

[0022] To give an optimal example here, in order to improve hydrophilicity, the base of the film (polymer silica) should be 60% by weight.
In order to reduce the odor by preventing the detachment and scattering of fine silica particles, the content of polymeric silica should be 80% by weight or less, and the content of water-dispersible polyamide resin, etc. should be 10% by weight. As mentioned above, the best results were obtained when the antibacterial agent content was 10% by weight or less.

As the antibacterial agent, for example, 2-(4-thiazolyl)-benzimidazole and 2.3.5.6-tetrachloro-4-(methylsulfonyl)pyridine are used, and the content thereof is 3 to 3. Make it 10% by weight.

Among these ingredients, 2-(4-thiazolyl)-benzimidazole has an antibacterial effect against mold, and 2.3.5.6-tetrachloro-4-(methylsulfonyl)pyridine has an antibacterial effect on mold. It has a wide range of antibacterial effects against microorganisms such as mold, bacteria, yeast, and actinomycetes.

(b) When polymer silica is used as a base, the viscosity of the surface treatment liquid can be kept low by appropriately setting the content of water-dispersible polyamide resin contained in the polymer silica. Therefore, the thickness of the surface treatment film (polymer silica film) can be reduced. As a result, cracking of the surface treatment film is prevented, and the surface treatment film itself is prevented from detaching.
It can prevent scattering and also prevent the surface treatment film from becoming sticky.

From the viewpoint of preventing cracks, the thickness of the polymer silica film is most preferably 1 μm or less, and according to the configuration of the present problem-solving means, such a film thickness can also be set.

[0027] From the viewpoint of preventing the above-mentioned cracking and film formation, it is preferable that the content of the water-dispersible polyamide resin, etc. is 40% by weight or less.

[0028] By performing the above actions (a) and (b),
The present invention exhibits excellent functions in terms of total hydrophilicity, durability, and odor resistance.

[Operation of the second problem-solving means] When the tubes, fins, etc. of the heat exchanger are immersed in a surface treatment liquid (for example, the treatment liquid that forms the polymer silica film) and then drained by air blowing, the set The surface treatment liquid tends to accumulate at the top and bottom of the heat exchanger, especially at the bottom of the heat exchanger, and the film tends to become very thick when dried.

However, according to the present problem solving means, the surface treatment liquid is Improves the ability to remove liquid from the lower part of the heat exchanger, where liquid tends to accumulate. As a result, unevenness in liquid drainage can be eliminated, the thickness of the coating can be set to an optimum thickness (for example, 1 μm or less), and cracking of the surface-treated coating can be prevented.

[Operation of the third problem-solving means] When draining the surface treatment liquid from the hydrophilic film of the heat exchanger, when the heat exchanger is set lying down or completely standing up, When the heat exchanger is set, a pool of liquid tends to form in the lower part (lower part) of the heat exchanger, and it takes time for the liquid to drain.

On the other hand, if the heat exchanger is drained by tilting it to some extent in the front-rear direction or left-right direction, the liquid pools can be suppressed, the time for draining the liquid can be shortened, and the uneven thickness of the top and bottom of the heat exchanger can be reduced. It turned out to be suppressed. Please refer to the experimental data described in the Examples section.

[0033]

[Embodiment] An embodiment of the present invention will be explained based on the drawings.

FIG. 1(a) is a perspective view of an evaporator (heat exchanger) to which the present invention is applied. The evaporator E of this example is a so-called serpentine-type evaporator in which fins 2 are arranged in a space formed by bending a heat transfer tube 1 into a meandering shape.

[0035] This evaporator E is a refrigeration cycle (not shown).
The refrigerant flowing through the refrigerant inlet 3 gradually vaporizes as it passes through the tube (heat transfer tube) 1 and flows out through the refrigerant outlet 4. When the refrigerant vaporizes, it removes heat of vaporization, and in this case, the air passing through the evaporator E is cooled by removing heat through the fins 2.

Evaporator E has a predetermined amount of chromate conversion film applied to the outer surface (surfaces of tubes, fins, etc.), and then a water-dispersible polyamide resin containing polymeric silica as the main component and an antibacterial agent. The evaporator E is immersed in the containing processing liquid for a predetermined time, and then the evaporator E is taken out from the processing liquid, and the processing liquid adhering to the evaporator E is adjusted to a predetermined thickness by air blowing. Next, the evaporator E is dried for a predetermined time in a drying oven set at a predetermined temperature. A schematic diagram of the surface treatment formed in this manner is shown in FIG. 1(b).

FIG. 1(b) shows the surface treatment structure of the fin 2. Reference numeral 5 indicates the aluminum base material constituting the fin 2, and the surface thereof is coated with crystals 6 of aluminum and silicon in the brazing filler metal, and residual flux. 7, on its upper surface is a chromic acid chromate conversion coating 8, further on its upper surface is a water-dispersible polyamide resin 9 embodying the present invention and an antibacterial agent 10.
An inorganic hydrophilic film 12 of polymeric silica 11 containing the following is formed, and the film has approximately two layers in total.

The coating 12 of this example is made of polymeric silica 11.
The content of water-dispersible polyamide resin 9 was 35% by weight, the content of antibacterial agent 10 was 5% by weight, and the film thickness was 1 μm or less. The details will be explained below.

First, the content of polymeric silica 11, which is the base of the present invention, will be explained. The purpose of polymer silica 11 is to be hydrophilic, and as shown in FIG. (If the resin 9 is the base), the water 13 adhering to the surface of the film becomes water droplets and acts as a resistance to the air passing through the evaporator E. On the other hand, as shown in Figure 3, if polymer silica 11 is the base and the silica content accounts for a large proportion of the entire film component, water attached to the film surface 1
3 forms a film and does not easily create resistance to the air passing through the evaporator E.

Therefore, the lower limit of the content of polymeric silica 11 was determined by first evaluating the hydrophilicity. Hydrophilicity was evaluated by the difference in ventilation resistance between wet and dry conditions when the front wind speed of evaporator E was 2.5 m/s. Further, in practical terms, the difference in ventilation resistance needs to be 20 (Pa) or less, and in consideration of durability, it needs to be 10 (Pa) or less. As shown in FIG. 4, the evaluation results show that if the content of polymer silica 11 is 60% by weight or more, the difference in ventilation resistance is 10 (Pa
) can be done. Therefore, the content of polymeric silica 11 needs to be 60% by weight or more. In this case, the content of the antibacterial agent 10 was set to be 10% by weight or less, and the maximum amount that could be contained within the range of 10% by weight or less was set.

On the other hand, if the content of polymer silica 11 is too large, polymer silica 11 is detached from inorganic hydrophilic film 12 and scattered as shown in FIG. Therefore, the relationship between the content of polymeric silica 11 and odor was investigated by sensory evaluation. The results of the sensory evaluation are shown in FIG. The odor evaluation values in FIG. 6 are as shown in Table 1.

[0042]

[Table 1]

The odor evaluation value needs to be 1 or less for practical purposes, and the odor evaluation value can be reduced to 1 or less if the content of polymeric silica 11 is 80% by weight or less. The odor evaluation values in FIG. 6 are the averages of eight panelists. From the viewpoint of odor, the content of polymeric silica 11 needs to be 80% by weight or less. As mentioned above, the polymer silica 11 is an inorganic hydrophilic film 1.
Since there is a risk of desorption from 2, it is necessary to minimize the content, and in this example, the content was set to 60% by weight.

Next, the content of the water-dispersible polyamide resin 9 will be explained. As shown in FIG. 7, if the content of the water-dispersible polyamide resin 9 is 10% by weight or more, the odor evaluation value can be made 1 or less. The odor evaluation values in FIG. 7 are the averages of eight panelists, and the odor evaluation values are as shown in Table 1.

The upper limit of the content of the water-dispersible polyamide resin 9 is evaluated based on cracks in the surface treatment film (inorganic hydrophilic film) 12 and film thickness of the surface treatment liquid during the film treatment process.

That is, as the content of the water-dispersible polyamide resin 9 is increased, the properties of the surface treatment liquid change when the content exceeds 50% by weight, and the surface treatment film 1
Cracks occur in 2. The reason for this is that when the viscosity of the surface treatment liquid increases due to the addition of the water-dispersible polyamide resin 9, the amount of surface treatment liquid that adheres to the surface of the evaporator E increases, and as a result, the film 12 becomes too thick. be. Figure 10
As shown in FIG.
There is a proportional relationship with the surface treatment liquid that adheres to the surface, and according to experiments on heating and cooling cycles, cracks occur when the thickness of the film becomes 1 μm or more. From the above, the thickness of the inorganic hydrophilic film 12 is set to 1 μm or less.

A specific example of a surface treatment technique for reducing the thickness of the film 12 to 1 μm or less will be described later.

Furthermore, when the content of the water-dispersible polyamide resin 9 becomes too large, a film 14 of the surface treatment liquid is formed so as to bridge the fins, as shown in FIG. The reason for this is that the viscosity of the surface treatment liquid is
This is because the surface treatment liquid is not completely drained because the surface treatment liquid rises due to an increase in the amount of water.

FIG. 9 shows the relationship between the viscosity of the surface treatment liquid and the film thickness. Here, the film coverage ratio is the ratio of the number of fins with film coverage to the total number of fins. When the blending ratio of the water-dispersible polyamide resin 9 exceeds 50% by weight and becomes resin-rich, the properties of the surface treatment liquid change as described above and the viscosity of the surface treatment liquid increases rapidly. In addition, the film tension ratio is zero when the blending ratio of the water-dispersible polyamide resin 9 ranges from 0 to 40% by weight, but it occurs when it exceeds 40% by weight, and increases rapidly when it exceeds 50% by weight. It can be seen that there is a correlation with the increase in viscosity of the processing liquid.

In this example, in order to improve hydrophilicity, P having a hydroxyl group was used as the water-dispersible polyamide resin 9.
VP (polyvinylpyrrolidone) was used, and the content was set to 35% by weight in consideration of the durability and odor of the film.

Next, the antibacterial agent 10 contains 2-(4-thiazolyl)-benzimidazole as an ingredient against mold, and 2.3.5 as an antibacterial agent against mold, bacteria, etc.
6-Tetrachloro-4-(methylsulfonyl)pyridine is blended in a predetermined ratio based on antibacterial activity, toxicity, cost, etc. The composition of this antibacterial agent is 2-(4-thiazolyl)-benzimidazole and 2.3.5.6-tetrachloro-4-(methylsulfonyl)pyridine in a ratio of 1:0.17 to 0.25. is preferable.

When such an antibacterial agent 10 is contained, mold resistance test (JIS Z2911) shown in FIG.
) As shown in the results, mold growth can be prevented at 3% by weight or more.

The evaluation values (0) to (3) used in FIG. 11 are as shown in Table 2.

[0054]

[Table 2]

[0055] The five types of test bacteria used in this case were Aspergillus, Penicillium, Aureobasidium, Gliocladium, and Pacilomyces.

[0056] Figure 1 shows the relationship between the content of antibacterial agent 10 and odor.
Shown in 2. The odor evaluation value is the average value of 8 panelists.
The evaluation criteria are as shown in Table 1 above. As shown in FIG. 12, it can be seen that when the antibacterial agent content is 10% by weight or less, the odor level is equivalent to that of a sample that does not contain antibacterial agent 10. The odor evaluation value increases when the amount is 10% by weight or more, as shown in Figure 13.
This is because the antibacterial agent 10 cannot be retained and bleeds out outside the film, and the bled-out antibacterial agent 10 is felt as an odor. From the above results, it is optimal that the content of the antibacterial agent 10 is 3 to 10% by weight. In this example, the content of antibacterial agent 10 was 5% by weight in consideration of durability.
And so.

Surface treatment film 12 configured as described above
The durability was evaluated. The durability of the film 12 was evaluated by evaluating hydrophilicity, antibacterial properties, and odor after conducting a running water test assuming a practical situation. The running water test was conducted for 36 cycles (36 days, equivalent to 3 years of practical use), with one cycle consisting of flowing a predetermined amount of tap water through the ventilation section of evaporator E for 7 hours per day and allowing it to air dry for 17 hours. The results are as follows.

(a) Hydrophilicity was evaluated based on the above-mentioned difference in air permeability resistance, and the result was 18 (Pa), which was not a problem for practical use.

(b) The antibacterial property was evaluated by the above mold resistance test, and the result was an evaluation value (0).
No mold growth was observed.

(c) Regarding odor, as a result of the above sensory evaluation, the odor evaluation value was 0.8 on average among the 8 panelists.
The result was that there was no problem in practical use.

[0061] Here, a method for treating the inorganic hydrophilic film 12 will be explained.

In general, this type of film treatment involves immersing the evaporator E in a surface treatment liquid consisting of film components, and then draining the evaporator and
Perform drying.

[0063] There are two types of liquid drains: centrifugal separation type and air blow type. In the former case, the centrifugal separator is expensive, the device is large, and the process of setting the evaporator E in the centrifugal separator is complicated, making it difficult to create a continuous process. Based on the above, I will try to adopt the latter method. However, in this method, simply draining the evaporator E with the arrangement shown in Figure 1 will cause uneven draining at the top and bottom of the evaporator E, and especially the surface treatment liquid will accumulate at the bottom of the heat exchanger, causing the heat exchange The film at the bottom of the container becomes too thick and tends to crack.

From the viewpoint of preventing cracks, it is desirable that the inorganic hydrophilic film 12 has a thickness of 1 μm. To this end, in this embodiment, a plurality of air injection nozzles 15 are arranged in the vertical direction as shown in FIG. By changing the wind speed, the wind speed distribution was set so that the wind speed gradually increased from the upper part of the evaporator E to the lower part.

By setting the wind speed distribution as described above, the surface treatment liquid that tends to accumulate in the lower part of the evaporator E can be blown away, and the film thickness in the lower part of the evaporator E can be adjusted to 1 μm or less, which prevents cracks from occurring. Specifically, for example, the upper and lower wind speed distribution is set to have a minimum of 3 to 5 m/s and a maximum of 8 to 10 m/s, but this wind speed varies depending on the shape of the evaporator E. The line of the wind speed distribution may be either a curve or a straight line, and the point is to increase the wind speed from about 1/3 of the lower part of the evaporator where liquid pooling is likely to occur.

Another point to be improved in the air blow method is how to shorten the time required for draining the liquid.

In this embodiment, the above problem is dealt with as follows.

The evaporator E is placed on a hanger 16 as shown in FIG. 14 during the draining process.

As shown in FIG. 14, if the angle when the evaporator E is tilted in the front-rear direction is X, and the angle when it is tilted in the left-right direction is Y, then when these angles X and Y are changed, We qualitatively investigated the liquid leakage properties.

First, when the angle .

Next, when the angle X is 90°, the evaporator E is in a completely horizontal position as shown in FIG. In this case, the surface treatment liquid 17 concentrates on the lower side of the set and flows down, but due to the structure in which the fins 3 are closely arranged, the surface treatment liquid 17 pools between the fins 3 due to surface tension, causing a liquid drain. becomes worse.

Next, when we examine the case where the angle Y is changed, FIG.
As shown in 8, the surface treatment liquid 1 is poured toward the bottom of the evaporator E.
It can be seen that the liquid pool in No. 7 becomes large, indicating that the liquid leakage at the bottom of the evaporator is poor.

Therefore, the time required to reduce the amount of surface treatment liquid 17 to a predetermined amount was investigated. As a result, as shown in FIG. 19, for the angle A result was obtained in which the time required to reduce the amount of surface treatment liquid 17 to a predetermined amount was the shortest.

FIG. 20 shows a surface treatment film in which the evaporator E is tilted in this manner.

As shown in FIG. 20, the film is thicker at the bottom of the evaporator E, and the maximum thickness of this film is 1 μm.
If the thickness is adjusted to less than m, the film will not crack, so there is no problem even if there is non-uniformity in the thickness under these conditions, and the time required for draining the surface treatment liquid 17 can be shortened.

[0076] The surface treatment method for changing the air velocity distribution and the technique for draining liquid by changing the angle of the evaporator E described above are applicable to the surface treatment liquid when the above-mentioned polymeric silica, water-dispersible resin,
In addition to those containing antibacterial agents, it can also be applied to other types of films.

Further, in this example, a serpentine type evaporator E was used, but the effect is the same even if a stacked type evaporator consisting of tube elements and fins are alternately stacked. be.

Furthermore, the resin contained in the polymer silica film 12 may be a water-dispersible polyamine resin instead of the water-dispersible polyamide resin. The difference between polyamide and polyamine is that the former is better in terms of hydrophilicity, while the latter is better in terms of durability. However, in terms of absolute values, both are orders of magnitude more hydrophilic and durable than other synthetic resins. It has excellent functions.

[0079]

As described above, according to the present invention, according to the first basic problem-solving means, polymer silica is used as the main component, and a resin such as water-dispersible polyamide and an antibacterial agent are added thereto. By incorporating it and forming a surface treatment film on the evaporator, the hydrophilicity of this type of film is significantly improved compared to conventional methods, and the effect of preventing the proliferation of microorganisms is further increased, and the film is prevented from detaching and scattering. It is possible to shorten the length of a heat exchanger that satisfies the requirements and has excellent performance and durability.

Further, according to the second means for solving the problem, it is possible to improve the drainage of the surface treatment liquid in the film forming process, to suppress the thickness of the film and to make it uniform, thereby preventing cracking of the film and improving durability. It is possible to improve sexual performance.

According to the third means for solving the problem, there is an effect of shortening the time of the draining step and suppressing the thickness of the film.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an evaporator E to which the present invention is applied, and a schematic diagram of a surface treatment film applied thereto.

FIG. 2 is an explanatory diagram of water repellency.

FIG. 3 is an explanatory diagram of hydrophilicity.

FIG. 4 is a diagram showing the relationship between the content of polymeric silica and hydrophilicity.

FIG. 5 is an explanatory diagram of odor caused by polymer silica.

FIG. 6 is a diagram showing the relationship between the content of polymeric silica and odor.

FIG. 7 is a diagram showing the relationship between the content of water-dispersible polyamide resin and odor.

FIG. 8 is an explanatory diagram of the film-forming phenomenon of surface treatment.

FIG. 9 is a diagram showing the relationship between the content of water-dispersible polyamide resin, cracking of the film, film tension, and viscosity of the surface treatment liquid.

FIG. 10 is a diagram showing the relationship between the amount of surface treatment liquid deposited and the thickness of the surface treatment film.

FIG. 11 is a diagram showing the antibacterial effect of the surface treatment film of the present invention.

FIG. 12 is a diagram showing the relationship between antibacterial agent content and odor.

FIG. 13 is an explanatory diagram of odor caused by antibacterial agents.

FIG. 14 is an explanatory diagram of air blowing in the surface film forming step of the present invention.

FIG. 15 is an explanatory diagram of the wind speed distribution of the air blow.

FIG. 16 is an explanatory diagram pointing out problems when performing surface treatment of a film.

FIG. 17 is an explanatory diagram pointing out problems when performing surface treatment of a film.

FIG. 18 is an explanatory diagram pointing out problems when performing surface treatment of a film.

FIG. 19 is a diagram showing the relationship between the set angle of the evaporator and the dripping time when performing surface treatment of a film.

FIG. 20 is a diagram showing the film thickness at each position of the evaporator when the film surface treatment method of the present invention is applied.

[Explanation of symbols]

E... Evaporator, 1... Tube, 2... Fin, 9... Water-dispersible polyamide resin, 10... Antibacterial agent, 11... Polymer silica, 12... Inorganic hydrophilic film, 15... Injection nozzle for air blow.

Claims (13)

[Claims] Claim 1: A heat exchanger comprising tubes and fins through which a refrigerant flows, and the outer surface of the heat exchanger is coated with a water-dispersible polyamide resin and a water-dispersible polyamine resin containing polymeric silica as a main component. 1. A heat exchanger comprising a polymeric silica film containing at least one type of resin and an agent for preventing the growth of mold, bacteria, etc. 2. The heat exchanger according to claim 1, wherein the content of the polymeric silica is 60 to 80% by weight. 3. According to claim 1 or 2, the content of at least one of the water-dispersible polyamide resin and the water-dispersible polyamine resin is 10 to 40% by weight.
A heat exchanger characterized by: [Claim 4] Any one of claims 1 to 3
2. The heat exchanger according to item 1, wherein the content of the chemical is 3 to 10% by weight. [Claim 5] Any one of claims 1 to 4
2, characterized in that an antibacterial agent consisting of 2-(4-thiazolyl)-benzimidazole and 2.3.5.6-tetrachloro-4-(methylsulfonyl)pyridine is used as the drug. heat exchanger. [Claim 6] Any one of claims 1 to 5
2. The heat exchanger according to item 1, wherein the polymer silica film has a thickness of 1 μm or less. [Claim 7] Any one of claims 1 to 6
2. The heat exchanger according to item 1, wherein the polymer silica film is formed on a corrosion-resistant chemical conversion film applied to the outer surface of the heat exchanger. 8. A heat exchanger manufacturing method in which a heat exchanger consisting of a tube through which a refrigerant flows, fins, etc. disposed integrally therewith is immersed in a surface treatment liquid, and then drained and dried. The processing liquid is drained using an air blow method that blows air onto the heat exchanger, and the wind speed distribution by the air blow is set so that the wind speed increases from the top to the bottom of the heat exchanger set at the blowing position. A method for manufacturing a heat exchanger characterized by performing liquid draining. 9. A method for manufacturing a heat exchanger, in which a heat exchanger consisting of a tube through which a refrigerant flows, fins, etc. disposed integrally with the tube is immersed in a surface treatment liquid, and then the liquid is drained and dried. The processing liquid is drained using an air blow method in which air is blown onto the heat exchanger, and the speed of the air blow is made so that the speed of the air blowing to the lower part of the heat exchanger set at the blowing position is higher than the wind speed blowing to other parts. A method for manufacturing a heat exchanger characterized by performing liquid draining. 10. In claim 8 or 9, the surface treatment liquid contains a drug that prevents the growth of mold, bacteria, etc. in polymeric silica, and a water-dispersible polyamide resin and a water-dispersible polyamine resin. A method for manufacturing a heat exchanger, characterized in that the treatment liquid contains at least one type of resin. 11. A heat exchanger manufacturing method in which a heat exchanger comprising a tube through which a refrigerant flows, fins etc. disposed integrally with the tube is immersed in a surface treatment liquid, and then the liquid is drained and dried. A method for manufacturing a heat exchanger, characterized in that draining of the processing liquid is performed by an air blowing method that blows air onto the heat exchanger, and is also performed while tilting at least one of the front-rear direction or left-right direction of the heat exchanger. 12. According to any one of claims 8 to 10, the draining of the surface treatment liquid is performed while tilting the heat exchanger in at least one of the front-rear direction or the left-right direction. Manufacturing method of heat exchanger. 13. In claim 11 or 12, the surface treatment liquid drain is set such that the inclination angle X in the front and back direction of the heat exchanger is set to be around 60°, and the inclination angle Y in the left and right direction of the heat exchanger is set to around 30°. A method for manufacturing a heat exchanger characterized by performing liquid draining.