JPS58208593A - Hidrophilic treatment of heat exchanger - Google Patents

Abstract

PURPOSE:To prevent the contamination from peeling and improve the efficiency of heat exchange, also lower the noise by the formation treatment of a hidrophilic film, further provide the hidrophilic treatment of heat exchanger designed for through-view prevention by the black color of said hidrophilic film. CONSTITUTION:A well-known heat exchanger 1 is consist of many thin plate fins 3 made of aluminum which is penetrated and extended by a heat exchange pipe 2 made of cupper and pipe plates 4 fitted to the both sides thereof. The surface of said fins 3 are treated solvent degreasing process by the solvent, also said surface of said fins 3 are activated by dipping said heat exchanger 1 in the alkali cleaning agent liquid solution, then its surface is made in rough condition. After said alkali cleaning liquid is removed by the water cleaning, said surface of said fins 3 are treated by chemical deposition 5 with zinc, water cleaning again, said fins 3 are covered by black color Molyblack family film 6, then last water cleaning, the hidrophilic treatment process is finished.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for hydrophilic treatment of a heat exchanger in which a heat exchange pipe is provided with a large number of aluminum thin plate fins.

For example, in a heat exchanger used as an evaporator in an air conditioner, dew water adheres to the entire surface of the aluminum fins during cooling operation, and if a bridge forms between the fins, the ventilation path becomes narrow, increasing noise and reducing heat exchange efficiency. invitation (there is a drawback)

For this reason, conventionally, hydrophilic paints made of synthetic silica, surfactants, acrylic synthetic resins, etc. were applied to the fins.
Heat exchangers are exposed to extremely harsh conditions in which dew condenses during cooling operation and dries when the operation is stopped, so-called wetting and drying cycles are repeated, so the hydrophilic paint peels off from the fins, and this coating becomes powdery and is exposed to wind. There was a risk that it would be blown out into the room.

In view of the above, the present invention aims to chemically treat the hydrophilic film to eliminate contamination due to peeling, improve heat exchange efficiency, reduce noise, and prevent see-through by using the black color of the hydrophilic film. The object of the present invention is to provide a hydrophilic treatment method for a heat exchanger, and in order to achieve this purpose, the surface of an aluminum fin is treated with alkali, zinc plated, and then coated with a moly black film. be.

Below, embodiments of the present invention will be explained based on the drawings.
In the figure, (1) shows a copper heat exchange pipe (2) and a large number of aluminum thin plate fins (2) extending through the pipe.
3) and tube plates (4) (4) fitted on both sides of the fins.
A well-known heat exchanger consisting of a fin (3
) The surface is treated with hydrophilic treatment as shown in the enlarged half-sectional view shown in FIG.

That is, a solvent degreasing step is carried out in which the surface of the fins (3) of the heat exchanger (1), which is constructed as shown in Fig. 1, is steam-cleaned with a solvent such as triethane or trichlene to remove dirt such as oil on the surface. After this, the heat exchanger ( ) is immersed in an alkaline detergent solution such as silicic acid (IJ) or caustic soda to activate the surface of the fins (3) and make the surface rough so that the plating described below will easily adhere to it. Toso-ku. Incidentally, since dirt such as oil can be removed at the same time in this alkali treatment step, it is not necessarily necessary to go through the solvent degreasing step described above.

After the alkali cleaning agent mentioned above is removed by washing with water, the surface of the fin (3) is chemically plated with zinc (5) to make it easier for a moly black film (6) to be described later to adhere thereto.

Next, after washing again with water, the fin (3) surface is coated with a black molyblank film (6) by immersing it in a moly black chemical solution containing ammonium molybdate and ammonium sulfate as main components, and washing with water 11:
And the hydrophilic treatment process is completed.

Since the moly black coating (6) has ultra-fine pores (7), it is preferable to seal the pores with chromate (8) to improve corrosion resistance.

Example 1 After solvent degreasing with upstream ethane, immersion in a 5% 50°C solution of Ridrin 53S (trade name of Nippon Paint Co., Ltd.) containing sodium metasilicate and sodium hornsilicate as main components for 1 minute, washing with water, and then washing with water. , zinc, and nitrite) T500 (trade name of Nichifu Parkerizing Co., Ltd.) 110. ! Accelerator 4 in i'/A'
Zinc plating was carried out for 3 minutes in a 30° C. solution containing g/l. Next, wash with water and add ammonium molybdate 25p/80
011f, ammonium sulfate 20g/800m/! , immersed in a mixed solution of 2 g of iron fugide/800 WLl at 70° C. for 1 minute, and then washed with water.

As a result, the hydrophilic heat exchanger (1) was uniformly blackened, and wettability was confirmed by a water spray test and it was found to be extremely good.

Example 2 After solvent degreasing with triethane, 5% of Ridrin 53S, 4
Immerse in 0°C solution for 30 seconds and wash with water, then precoat T 500110g/A! Zinc plating was carried out for 30 seconds in a 30° C. solution containing 4⁄L promoter. Next, it was washed with water, immersed for 1 minute in a 70°C solution of Alblak T500 (trade name of Nippon Barker Rising Co., Ltd. + As a result, as shown in Table 1, the uninvented hydrophilic treated product (■) with this Molyblack-based film, the untreated product (■) in which the fin (3) surface was not subjected to hydrophilic treatment at all, and the untreated product (■) with a chromate film on the fin (3) surface. Static pressure loss and fins (3) compared with the chromate-treated product ■ that was only treated and the hydrophilic painted product ■ that was coated with the hydrophilic paint described above as a conventional example.
It was found that the amount of water held by the product was small, and the cooling capacity, blower power, and noise performance were all improved compared to the untreated product (2). In addition, in Table 1, the static pressure loss and the amount of water retained are the values when the untreated product ■ is set as 100 at a front wind speed of 0.5 m/S, and the performance of the cooling capacity and blower power The test measured the fin (3) pitch 16 with the fin (3) pitch 2 m as the standard, and the noise performance test measured the fin (3) pitch 16 with the fin (3) pitch 2 m as the standard. This is what was measured.

Table 1 Example 3 Hydrophilic treated product ■ and sealing treatment of the treated product with chromate (8) (trade name Chemimeta AL2 of Chemister Co., Ltd.
A running water test in which the treated product ■' was immersed in water for 300 hours, and a constant temperature and humidity test in which it was left in a refrigerator at 50 degrees Celsius and 95% humidity for 300 hours.
As a result of a comparison with a water sprinkling test in which one cycle of watering for 30 minutes and leaving it outside for 2 hours and 30 minutes was repeated 100 cycles, the hydrophilic treated product (■) had a very slight black moly black film, which was practically no problem. Peeling and white powder in (6) were observed, and it was found that the corrosion resistance and appearance were slightly inferior to the treated product (■').

As described above (according to the method of the present invention, by coating the fin surface with a moly black film after alkali treatment and zinc plating, it is possible to eliminate contamination due to film peeling, and the moly black film has an excellent hydrophilic effect. This improves heat exchange efficiency and reduces noise. At the same time, the blackening of the moly black film prevents external visibility of the heat exchanger incorporated in the air conditioner, thereby improving the appearance.

[Brief explanation of the drawing]

FIG. 1 is a front view of a heat exchanger subjected to hydrophilic treatment by the method of the present invention, and FIG. 2 is an enlarged half-sectional view of FIG. 1. (1)...Heat exchanger, (2)-...Heat exchange pipe, (
3)... Aluminum thin plate fin, (5)... Zinc plating, (6)... Warp black film. Applicant Sanyo Electric Co., Ltd. and one other agent Patent attorney Shizuo Sano District L Ward 2/7

Claims (1)

[Claims] (1) In a heat exchanger in which a heat exchange pipe is provided with a large number of aluminum thin plate fins, the surface of the fins is treated with alkali, zinc plated, and then coated with a moly blank film. Hydrophilic treatment method.