JP4990413B2 - Manufacturing method of heat exchanger - Google Patents

Description

  The present invention relates to a method of applying an antifouling coating to a device processed into a complicated shape such as a heat exchanger for an air conditioner, and particularly relates to a process of forming a uniform film by applying a coating liquid and drying it. .

  Heat exchangers that perform heat exchange of air conditioners usually have complicated shapes of metal fins and heat transfer tubes, but in recent years, from the viewpoint of simplification of cleaning and antibacterial purposes, to prevent the adhesion of dirt and bacteria Antifouling coating is applied. Such an antifouling coating is required to have both hydrophilicity and hydrophobicity, and therefore has a high aqueous solvent ratio. When such a coating solution is applied, a drying process is important in which the gap is narrow and the residual components are left appropriately. It was necessary to make the thickness of the coating film uniform.

  For such problems, suspend the object to be processed on the hanger, transfer the object to be processed from the main conveyor to the sub-conveyor using the hanger removable conveyor, and remove excess liquid adhered in the previous process using the centrifuge. Drain the liquid. Then, return from the sub-conveyor to the main conveyor to perform the next process, prevent excess adhering liquid in the previous process from being brought into the next process, keep the concentration of the processing liquid constant, A device has been devised to make the thickness uniform and improve the quality (for example, Patent Document 1).

  Further, the heat exchanger assembly is placed in the rotating basket of the centrifuge in a mode in which the tube length direction is aligned with the radial line direction and centrifuged, and the retained liquid is sufficiently evenly distributed. A device for efficiently draining the liquid is made (for example, Patent Document 2).

JP-A-6-10150 JP-A-6-297140

  However, the above-described conventional method using centrifugal separation has a problem in terms of cost due to the large equipment. In addition, it is difficult to sufficiently drain the liquid simply by air blowing, and there is a problem that film unevenness occurs when the film is coated due to poor liquid drainage.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method capable of forming a uniform coating film without unevenness by sufficiently draining liquid with a simple configuration.

Method of manufacturing a heat exchanger according to the present invention, the heat and process for manufacturing the heat exchanger are assembled a plurality of fins and the heat transfer tube, a coating liquid hydrophobic resin particles in water medium is dispersed From the coating step to be applied to the exchanger and the gas jets provided in at least two directions above and below the heat exchanger to which the coating liquid has been applied, to the intersection of the fins of the heat exchanger and the heat transfer tubes And a gas blasting step in which the gas in the two directions is collided and blasted.

  According to the present invention, the coating liquid adhering to the apparatus can be sufficiently drained by a simple gas spraying device, and a uniform coating film without unevenness can be formed.

It is explanatory drawing which shows the outline of the coating method concerning Embodiment 1 of this invention. It is explanatory drawing which shows the outline of the coating method concerning Embodiment 1 of this invention. It is explanatory drawing which shows the outline of the coating method concerning Embodiment 1 of this invention. It is explanatory drawing which shows the outline of the coating method concerning Embodiment 1 of this invention. It is explanatory drawing which shows the outline of the coating method concerning Embodiment 2 of this invention. It is explanatory drawing which shows the outline of the coating method concerning Embodiment 2 of this invention. It is explanatory drawing which shows the outline of the manufacturing method of the heat exchanger concerning Embodiment 3 of this invention. It is a block diagram which shows the outline of the heat exchanger concerning Embodiment 3 of this invention. It is an electron micrograph of the section of the coating film concerning the present invention.

Embodiment 1 FIG.
FIG. 1 is an explanatory diagram showing an outline of a coating method for equipment in Embodiment 1 of the present invention. A cleaning step (a) in which the heat exchanger 1 including the fins 15 and the heat transfer tubes 3 is immersed in the cleaning liquid 2 in the dip tank 51, and a rinsing step in which the heat exchanger 3 is immersed in the rinsing liquid 6 in the dip tank 52 ( b) and a coating step (c) in which the heat exchanger 1 is immersed in the coating liquid 7 in which hydrophobic resin particles are dispersed in the aqueous medium in the dip tank 53.
Further, as shown in FIG. 2, air is supplied to predetermined positions of the heat exchanger 1 from gas jets 91 and 92 provided in at least two directions above and below the heat exchanger 1 to which the coating liquid 7 is applied. The heat exchanger 1 is moved while spraying 101 and 102.
Here, for example, the airs 101 and 102 are sent from the blowers 81 and 82 and are moved by the conveyor 11 that holds the end of the heat exchanger 1, so that the air 101 and 102 are almost the same predetermined heat exchanger 1. Spray to the position.
The air currents of the air 101 and 102 collide with each other to always create an air current collision region. As a result, the pressure in the vicinity of a complicated shape such as the intersection of the fin 15 of the heat exchanger 1 and the heat transfer tube 3 rises, and the hydrophobic resin particles are removed from the heat exchanger in order to remove the aqueous medium in the coating liquid 7. 1 can be uniformly applied to the surface. When the airflow is only in one direction, the coating liquid 7 tends to accumulate on the surfaces of the fins 15 and the heat transfer tubes 3, and the film partially thickens, which is one of the causes of unevenness.

  Here, it is preferable that the jet outlets 91 and 92 have the width of the heat exchanger 1 because the air 101 and 102 can be efficiently moved to the entire heat exchanger 1. If an airflow collision region with a wind speed of 30 m / s can be obtained, the aqueous medium can be sufficiently removed by the collision and can be uniformly applied to the surface. Usually, the wind speed of air can be supplied at about 15 to 20 m / s, and the width of the heat exchanger 1 is about 60 cm. Therefore, in order to obtain an airflow collision region with a wind speed of 30 m / s, the short side should be 10 cm or less. Is preferred.

  That is, by making the short side 10 cm or less, the air flow generated from the jet outlets 91 and 92 becomes sharp, and when the gas collides, the pressure in the vicinity of the complicated shape by the heat transfer tube 3 of the heat exchanger 1 increases. In order to remove the aqueous medium in the coating liquid 7, the hydrophobic resin particles can be uniformly applied to the surface of the heat exchanger 1. On the other hand, since an aqueous medium will remain if an air flow is generated too much, the short side is preferably 3 cm or more.

The blowing position of the air 101, 102 is about 5 cm from the surface of the heat exchanger 1, and the wind speed is preferably 20 m / s or more and 40 m / s or less. If it is less than 20 m / s, a sufficient pressure rise cannot be expected even if a collision airflow is generated. If it is 40 m / s or more, the heat exchanger 1 that moves on the conveyor 11 may fall. More preferably, it is 25 m / s or more and 35 m / s or less.
The temperature of the air 101, 102 is preferably 25 ° C. or higher and 50 ° C. or lower. If it is too low, the coating liquid 7 remains. If it is too high, the coating liquid 7 is dried before it blows off from the surface of the heat exchanger 1, and the film thickness becomes uneven.

Furthermore, the remaining aqueous medium is removed by providing a drying step of about 90 ° C. or higher and 110 ° C. or lower after the step of blowing air. As a result, odor adsorption and mold generation due to the residual aqueous medium can be prevented.
Drying in the drying step can be performed using warm air, infrared rays, or a heating furnace. If the drying temperature is low, the coating liquid 7 remaining inside the heat exchanger 1 cannot be completely removed, and if it is too high, the performance of the formed coating film may be deteriorated. When hydrophilic particles are included in the coating liquid 7 by the drying step, there is also an effect of firmly adhering the particles and the base material of the heat exchanger 1. The wind speed in the drying step is preferably 10 m / s or less.

  In the present embodiment, the air exchangers 91 and 92 provided in at least two directions above and below the device 1, for example, a heat exchanger to which the coating liquid 7 is applied, are placed at predetermined positions on the device 1. In the air blasting process in which the device 1 is moved while the two airs 101 and 102 collide with each other, the upper and lower air angles are made to collide with the surface of the device approximately 90 degrees using FIG. Although the example has been described, as shown in FIG. 3, angles 103 and 104 of the upper and lower air with respect to the device surface may be provided, and the positions may be determined and collided. In FIG. 3, the upper air angle 103 with respect to the device surface is an acute angle, and the lower air angle 104 is an obtuse angle. In FIG. 4, both the angles 103 and 104 are acute angles. In order to secure the wind velocity and airflow collision area, sufficiently remove the aqueous medium by gas collision, and make the coating film 18 uniform, it is preferable to determine the angles 103 and 104 within a range of 40 degrees to 135 degrees. . This is because, particularly when the shape of the device 1 is complicated, it is necessary to give a sufficient collision force to the upper and lower gases to effectively increase the pressure. This pressure can also prevent the coating liquid pool from remaining in the device.

Embodiment 2. FIG.
FIG. 5 is an explanatory diagram showing an outline of a coating method for equipment in the second embodiment of the present invention. As in the first embodiment, after passing through the washing step (a), the rinsing step (b), and the coating step (c), it is provided in at least two directions above and below the heat exchanger 1 to which the coating liquid 7 is applied. The heat exchanger 1 is moved from the gas jets 91 and 92 while jetting air 101 and 102 to predetermined positions of the heat exchanger 1.
Here, for example, the air 101 and 102 are sent from the blowers 91 and 92 having a predetermined wind speed, and are sprayed to substantially the same predetermined position of the heat exchanger 1. Further, the air 101 and 102 are jetted from above and below by moving the blowers 91 and 92 in synchronization by the jet outlet moving mechanisms 131 and 132. The blowers 91 and 92 may be fixed and the heat exchanger 1 may be moved.
The air currents of the airs 101 and 102 collide with each other in the same manner as in the first embodiment to always create an air current collision region. As a result, the pressure in the vicinity of the complicated shape by the heat transfer tube 3 of the heat exchanger 1 rises, and hydrophobic resin particles are uniformly applied to the surface of the heat exchanger 1 in order to remove the aqueous medium in the coating liquid 7. can do.
Furthermore, if the heat exchanger 1 is moved by the conveyor 11, air can be sprayed on the entire surface of the heat exchanger 1.
As in the first embodiment, the air blowing position is about 5 cm from the surface of the heat exchanger 1, and the wind speed is preferably 20 m / s or more and 40 m / s or less. More preferably, it is 25 m / s or more and 35 m / s or less. The air temperature is preferably 25 ° C. or higher and 50 ° C. or lower.

  In the present embodiment, the air exchangers 91 and 92 provided in at least two directions above and below the device 1, for example, a heat exchanger to which the coating liquid 7 is applied, are placed at predetermined positions on the device 1. Regarding the air blasting process in which the device 1 is moved while being struck by causing the air 101 and 102 in two directions to collide with each other, the angles of the upper and lower airs 101 and 102 with respect to the surface of the device 1 are approximately Although the example in which the collision is performed at 90 degrees has been described, as in the first embodiment, for example, as shown in FIG. You may make it swing the upper and lower air, respectively. In order to secure the wind velocity and airflow collision area, sufficiently remove the aqueous medium by gas collision, and make the coating film 18 uniform, it is preferable to determine the angles 103 and 104 within a range of 40 degrees to 135 degrees. .

  In the first and second embodiments, the method of generating airflow using air has been described. However, other gases such as nitrogen and argon may be used.

  Although an example in which gas is sent from two directions has been described, an airflow collision region may be created by sending three or more directions.

  Although the example which uses the apparatus to coat as the metal heat exchanger 1 was shown, apparatuses, such as a housing | casing and filter of an air conditioner which has a vane, may be sufficient. It may be a plastic member. Even when coating on a device having a complicated shape such as a blade body of a ventilation fan, the effect of the present invention can be produced, which can form a uniform coating film without unevenness.

  Although the method of immersing the heat exchanger 1 in the dip tank 53 and applying the coating liquid 7 has been described, the method of applying may be sprayed with a spray or the like.

Although the example using the coating liquid 7 in which hydrophobic resin particles are dispersed in an aqueous medium has been described, the coating liquid 7 may include hydrophilic inorganic particles.
It is preferable that silica fine particles, titanium fine particles, titania, alumina, and the like are appropriately contained because water is compatible with the coating layer. Silica fine particles have a refractive index close to that of plastic, glass, etc., and thus can give a transparent feeling. By including these inorganic fine particles, it is possible to avoid whitening or glare due to light reflection at the interface or surface with the base material. The average particle size of the inorganic fine particles is preferably about 15 nm or less. This is because the hydrophobic resin particles are projected onto the surface, and the substrate of the coating film is formed with fine fine particles.
In particular, in the case of silica fine particles having a particle diameter in the range of 4 to 15 nm, the surface portion corresponding to approximately 15 to 30% of the weight of the silica fine particles is about half of water in the coating liquid containing the aqueous medium. It is in a dissolved state. When the average particle diameter exceeds 15 nm, the weight of the silica component dissolved in the water in the coating liquid with respect to the weight of the silica fine particles decreases, and the action as a binder cannot be obtained. For this reason, the coating film formed on the article does not have sufficient strength, and cracks easily occur. On the other hand, in the silica fine particles having an average particle size of less than 4 nm, the ratio of the silica component dissolved in water becomes too high, and the silica particles are aggregated. The particle size of the silica fine particles also affects the appearance of the formed coating film. If the silica fine particles have an average particle size of 15 nm or less, the scattering of light reflected by the coating film is reduced, thereby improving the transparency of the coating film and suppressing changes in the color tone and texture of the coating object. The color tone and texture can be maintained.

  The amount of silica fine particles added in the coating liquid 7 is preferably 0.5% by mass or more and 5% by mass or less, and more preferably 1% by mass or more and 4% by mass or less. If the amount is too small, the inorganic fine particles are sparse and the base of the film cannot be formed. If the amount is too large, the substrate of the film becomes too thick and cracks are likely to occur.

Embodiment 3 FIG.
FIG. 7 is an explanatory diagram showing an outline of a method for manufacturing a heat exchanger according to Embodiment 3 of the present invention. For example, a plurality of aluminum fins 15 and the heat transfer tubes 3 are assembled to produce the heat exchanger 1 (FIG. 7A), the heat exchanger 1 is immersed in the cleaning liquid 2, and the heat exchanger 1 is rinsed 6 The coating liquid 7 in which hydrophobic resin particles are dispersed in an aqueous medium is applied to the heat exchanger 1. As a result, the coating liquid 7 tends to accumulate at the intersection of the fins 15 and the heat transfer tubes 3 due to surface tension, and it is difficult for the liquid to run out (FIG. 7B).
Next, the gas 101, 102 in two directions collides with a predetermined position of the heat exchanger 1 from the gas outlets 91, 92 provided in at least two directions above and below the heat exchanger 1 to which the coating liquid 7 is applied. Let it spout. The aqueous medium in the coating liquid 7 is removed by the pressure increase in the region where the airflow collides. Thereafter, the coating liquid 7 is dried, and the brazing ports 4 of the heat transfer tubes 3 are connected by a plurality of pipes 16 to form a medium passage (FIG. 7C). Through the above-described steps, a uniform coating film without unevenness is formed, and the heat exchanger 17 having excellent appearance and antifouling properties can be manufactured (FIG. 8).

In the present embodiment and the first and second embodiments, the thickness of the coating film 18 formed by the drying process is not particularly limited, but is preferably 0.1 μm or more and 0.5 μm or less. If the thickness exceeds 0.5 μm, the uniformity of the coating film 18 is impaired and cracks are likely to occur, and dirt may accumulate in the cracks, resulting in a decrease in antifouling performance. If the thickness is less than 0.1 μm, hydrophobic resin particles cannot be sufficiently dispersed on the surface of the coating film 18 and sufficient antifouling performance cannot be exhibited.
FIG. 9 is an electron micrograph of a cross section of the coating film 18 when the thickness of the coating film 18 is changed. When the film thickness is 0.35 μm (a), the uniform coating film 18 is formed on the surface of the device 1, whereas when the film thickness is 0.66 μm, the uniformity is obtained (b). It turned out to be difficult to secure.

  Hereinafter, by showing specific examples, it will be described using comparative examples that a uniform coating film without unevenness can be formed by the coating method according to the present invention and that good appearance characteristics and antifouling characteristics can be obtained. To do.

  In Examples 1 to 11 and Comparative Examples 1 and 2, the heat exchanger 1 for an air conditioner having a large number of aluminum heat transfer tubes 3 was used.

Example 1.
A coating liquid 7 was prepared by stirring and mixing deionized water and 2% by mass of titanium oxide sol (made by Showa Denko) having an average particle diameter of 20 nm, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Machinery Co., Ltd.) in the gas spraying process has a long side of 60 cm and a short side of 10 cm, and the apparatus shown in FIG. I collided. The air velocity was 35 m / s and the temperature was 40 ° C. Further, drying was performed at a wind speed of 10 m / s and a temperature of 95 ° C. The speed of the conveyor 11 was 1.2 m / min.

Example 2
A coating liquid 7 was prepared by stirring and mixing deionized water and 2% by mass of colloidal silica (Nissan Chemical Co., Ltd.) having an average particle diameter of 5 nm, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Industries Co., Ltd.) in the gas blowing process has a long side of 60 cm and a short side of 11 cm, and the upper air 101 and the lower air 102 are at an angle of 90 ° using the apparatus shown in FIG. I collided. The air speed was 35 m / s and the temperature was 25 ° C. A drying step was provided in the same manner as in Example 1. The speed of the conveyor 11 was set to 1.2 m / min as in the first embodiment.

Example 3
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Industry Co., Ltd.) has a long side of 60 cm and a short side of 8 cm in the gas blowing process. The apparatus shown in FIG. 2 is used, and the upper air 101 and the lower air 102 are at an angle of 90 °. I collided. The air velocity was 35 m / s and the temperature was 50 ° C. A drying step was provided in the same manner as in Example 1. The speed of the conveyor 11 was set to 1.2 m / min as in the first embodiment.

Example 4
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Industry Co., Ltd.) has a long side of 60 cm and a short side of 8 cm in the gas blowing process. The apparatus shown in FIG. 2 is used, and the upper air 101 and the lower air 102 are at an angle of 90 °. I collided. The air speed was 35 m / s and the temperature was 20 ° C. A drying step was provided in the same manner as in Example 1. The speed of the conveyor 11 was set to 1.2 m / min as in the first embodiment.

Example 5 FIG.
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Industry Co., Ltd.) has a long side of 60 cm and a short side of 8 cm in the gas blowing process. The apparatus shown in FIG. 2 is used, and the upper air 101 and the lower air 102 are at an angle of 90 °. I collided. The air speed was 35 m / s and the temperature was 55 ° C. A drying step was provided in the same manner as in Example 1. The speed of the conveyor 11 was set to 1.2 m / min as in the first embodiment.

Example 6
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Industry Co., Ltd.) in the gas spraying process has a long side of 60 cm and a short side of 5 cm, and the apparatus shown in FIG. I collided. The air speed was 40 m / s and the temperature was 40 ° C. A drying step was provided in the same manner as in Example 1. The speed of the conveyor 11 was set to 1.2 m / min as in the first embodiment.

Example 7
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Machinery Co., Ltd.) in the gas blowing process has a long side of 60 cm and a short side of 20 cm, and the apparatus shown in FIG. I collided. The air velocity was 15 m / s and the temperature was 40 ° C. A drying step was provided in the same manner as in Example 1. The speed of the conveyor 11 was set to 1.2 m / min as in the first embodiment.

Example 8 FIG.
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Industry Co., Ltd.) has a long side of 60 cm and a short side of 8 cm in the gas blowing process. The apparatus shown in FIG. 2 is used, and the upper air 101 and the lower air 102 are at an angle of 90 °. I collided. Moreover, the wind speed of air was 35 m / s and the temperature was 40 degreeC. Further, drying was performed at a wind speed of 10 m / s and a temperature of 120 ° C. The speed of the conveyor 11 was 1.2 m / min.

Example 9
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Industry Co., Ltd.) has a long side of 60 cm and a short side of 8 cm in the gas blowing process. The apparatus shown in FIG. 2 is used, and the upper air 101 and the lower air 102 are at an angle of 90 °. I collided. Moreover, the wind speed of air was 35 m / s and the temperature was 40 degreeC. Further, drying was performed at a wind speed of 10 m / s and a temperature of 85 ° C. The speed of the conveyor 11 was 1.2 m / min.

Example 10
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Industries Co., Ltd.) in the gas blowing process has a long side of 60 cm and a short side of 8 cm, and the upper air 101 and the lower air 102 are at an angle of 45 ° using the apparatus shown in FIG. I collided. Moreover, the wind speed of air was 35 m / s and the temperature was 40 degreeC. Further, drying was performed at a wind speed of 10 m / s and a temperature of 95 ° C. The speed of the conveyor 11 was 1.2 m / min.

Example 11
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Industry Co., Ltd.) in the gas blowing process has a long side of 60 cm and a short side of 8 cm, and the apparatus shown in FIG. I collided. Moreover, the wind speed of air was 35 m / s and the temperature was 40 degreeC. Further, drying was performed at a wind speed of 10 m / s and a temperature of 95 ° C. The speed of the conveyor 11 was 1.2 m / min.

Comparative Example 1
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Industry Co., Ltd.) in the gas blasting process had a long side of 60 cm and a short side of 8 cm, and only the upper air 101 was sprayed at 90 ° using the apparatus shown in FIG. Moreover, the wind speed of air was 35 m / s and the temperature was 40 degreeC. Further, drying was performed at a wind speed of 10 m / s and a temperature of 95 ° C. The speed of the conveyor 11 was 1.2 m / min.

Comparative Example 2
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Machinery Co., Ltd.) has a long side of 60 cm and a short side of 20 cm in the gas blowing process. The apparatus shown in FIG. 2 is used, and the upper air 101 is 110 ° and the lower air 102 is 45 °. (The upper air and the lower air do not collide). Moreover, the wind speed of air was 35 m / s and the temperature was 40 degreeC. Further, drying was performed at a wind speed of 10 m / s and a temperature of 95 ° C. The speed of the conveyor 11 was 1.2 m / min.

  Table 1 summarizes the general conditions and evaluation results for Examples 1 to 11 and Comparative Examples 1 and 2.

The film appearance is visually. The mass difference before and after drying was determined, and the residual state of the coating solution was evaluated. The larger the value, the more coating liquid remains, and the drying is not sufficient.
The contact angle θ was measured with a contact angle meter (DM100 manufactured by Kyowa Interface Chemical Co., Ltd.). If the numerical value was less than 20, it was judged that good hydrophilicity was shown.
Adhesion was evaluated by spraying carbon black, a hydrophobic (oil-based) fouling substance. By visual observation, ◎ indicates that the amount of adhesion is very small, ◯ indicates that the amount of adhesion is small, △ indicates that there is little adhesion, and X indicates that the amount of adhesion is large. did. When the coating film has a lot of film unevenness, carbon black tends to adhere due to surface irregularities.

  Table 1 shows that both the film appearance and the carbon black adhesion preventing property are improved when the gas spraying steps of Examples 1 to 11 according to the present invention are provided. In particular, when the blower short side dimension was set to 10 cm or less, a thin coating film having a uniform thickness could be formed. From the electron microscope image, the coating film thickness was about 100 nm to 200 nm. It was confirmed by visual observation that the film was transparent.

  In Example 5, the temperature in the gas spraying process was high, and it seemed that the coating liquid 7 was dried and solidified before the coating liquid 7 was blown off, and a part of the film became a cloudy film. The temperature in the gas blowing step is preferably 25 ° C. or higher and 50 ° C. or lower.

  In Example 7, it was considered that the coating liquid remained in part because the gas wind speed was low in the gas spraying process, and the part became a cloudy film when fixed by the drying process. The wind speed is preferably 20 m / s or more and 40 m / s or less.

  It was also found that the film appearance and carbon black adhesion can be further improved by considering the conditions of the wind speed and temperature of the upper and lower gases in the gas blowing step. In Example 3, the anti-adhesion property was most improved under the conditions of a gas angle of 90 °, a blower short side of 10 cm, a wind speed of 35 m / s, and a temperature of 50 ° C.

  In Comparative Example 1, since only the upward spraying is performed, the pressure at a complicated portion in the heat exchanger 1 cannot be increased, and the coating liquid 7 remains. It can also be seen that the mass difference before and after the drying treatment is large. It seems that the remaining part of the coating film is thick and becomes a white turbid film. When carbon black is attached, it is likely that the film will be caught due to unevenness of the film, so that it is considered impossible to secure adhesion prevention.

  In Comparative Example 2, air was sprayed from above and below, but if the angles do not match, the collision does not occur, and the effect cannot be expressed.

Example 12
A coating liquid 7 was prepared in the same manner as in Example 2, and the heat exchanger 1 was immersed therein. The blower device (manufactured by Asia Chemical Machinery Co., Ltd.) in the gas blowing process has a long side of 60 cm, a short side of 5 cm, and an angle 103 with respect to the surface of the heat exchanger 1 of the upper air 101 using the device shown in FIG. The angle 104 of the lower air 102 with respect to the surface of the heat exchange element 1 was collided at 30 degrees. Moreover, the wind speed of air was 35 m / s and the temperature was 40 degreeC. Further, drying was performed at a wind speed of 10 m / s and a temperature of 95 ° C. The speed of the conveyor 11 was 1.2 m / min.

Example 13
In the same manner as in Example 12, air was sprayed from above and below the heat exchanger 1 to which the coating liquid 7 was applied. The upper air angle 103 and the lower air angle 104 were each 40 degrees.

Example 14
In the same manner as in Example 12, air was sprayed from above and below the heat exchanger 1 to which the coating liquid 7 was applied. The upper air angle 103 and the lower air angle 104 were each 135 degrees.

Example 15.
In the same manner as in Example 12, air was sprayed from above and below the heat exchanger 1 to which the coating liquid 7 was applied. The upper air angle 103 and the lower air angle 104 were 140 degrees.

Table 2 shows the conditions and evaluation results of Examples 12 to 15. In any case, the contact angle θ is less than 20 and shows good hydrophilicity. However, as for the film appearance, Example 13 in which the upper air angle 103 and the lower air angle 104 (spraying angle) are 40 degrees and 135 degrees is shown. 14, a transparent film was formed and the visibility was excellent, but in Examples 12 and 15 in which the angle 103 was 30 degrees and 140 degrees, slight cloudiness was observed.
When the spray angle 103 is less than 40 degrees or exceeds 135 degrees, a sufficient collision force cannot be obtained at the time of gas collision, and the pressure cannot be sufficiently increased. Therefore, it is considered that the coating liquid can be accumulated in a particularly complicated portion of the device 1 and the uniformity is impaired. Further, in Examples 12 and 15, it was considered that the coating film was uneven and carbon black was easily attached.

1 Equipment, heat exchanger, 2 cleaning liquid, 3 heat transfer tube, 4 brazing port, 51, 52, 53 dip tank, 6 rinse liquid, 7 coating liquid, 81, 82 blower, 91, 92 jet outlet, 101, 102 air , 103, 104 Gas angle, 11 Conveyor, 12 Movement direction, 131, 132 Jet outlet movement mechanism, 141, 142 Air movement direction, 15 Fin, 16 Pipe, 17 Heat exchanger, 18 Coating film

Claims (10)

Assembling a plurality of fins and heat transfer tubes to produce a heat exchanger ,
Water medium coating solution hydrophobic resin particles dispersed in a coating step of applying to the device,
Gas that moves the device while the gas in two directions collides with a predetermined position of the device from a gas outlet provided in at least two directions above and below the device to which the coating liquid is applied. Spraying process and
A method of manufacturing a heat exchanger, comprising: The heat exchanger according to claim 1, further comprising a drying step for drying the coating solution, wherein the coating film formed in the drying step has a thickness of 0.1 µm to 0.5 µm. Method. Long side of the upper and lower the gas injection outlet is parallel to the heat transfer tube of the heat exchanger, the heat exchanger according to claim 1, characterized in that perpendicular to the fin Production method. The angle of the upper and lower gas in the gas blowing process with respect to the device surface is in the range of 40 degrees or more and 135 degrees or less, and each position and the angle so that the upper gas and the lower gas collide with each other. The method for manufacturing a heat exchanger according to claim 1, wherein: is determined. 2. The method for manufacturing a heat exchanger according to claim 1, wherein a short side of the gas outlet in the gas injection step is 3 cm or more and 10 cm or less. The method for manufacturing a heat exchanger according to claim 1, wherein the wind speed of the gas in the gas blowing step is 20 m / s or more and 40 m / s or less. The method for producing a heat exchanger according to claim 1, wherein the temperature of the gas in the gas blowing step is 25 ° C or higher and 50 ° C or lower. The method for producing a heat exchanger according to claim 1, wherein the drying temperature in the drying step is 90 ° C. or higher and 110 ° C. or lower. A cleaning step of immersing the above Symbol heat exchanger in the cleaning liquid,
A rinsing step of immersing the heat exchanger in a rinsing liquid ;
A drying step of drying the upper Symbol coating solution,
The method for manufacturing a heat exchanger according to claim 1, further comprising a step of connecting a brazing port of the heat transfer tube with a plurality of pipes to form a medium passage. The method for producing a heat exchanger according to claim 1, wherein the coating liquid contains an aqueous medium and silica particles.

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