JPS63134693A - Production of aluminum fin material for heat exchanger - Google Patents

Abstract

PURPOSE:To produce an Al fin material for a heat exchanger maintaining superior hydrophilic property by forming an alumite layer on the surface of Al or an Al alloy, impregnating a surfactant into the porous surface of the alumite layer and half-sealing the pores. CONSTITUTION:A porous alumite layer 3 having many pores 4a... is formed on the surface of an Al or Al alloy fin material 2 by anodic oxidation to obtain an unsealed alumite fin material 1. A surfactant 6 is filled into the pores 4a... and the porous alumite layer 3 is treated with compressed steam or the like to half-seal the pores 4a.... When the resulting half-sealed alumite fin material 5 is used as a fin material for a heat exchanger, the surfactant 6 leaches gradually out of the half-sealed pores 7a... to remove oil sticking to the surface of the fin material 2, so the fin material maintains superior hydrophilic property over a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing an aluminum fin material for a heat exchanger, and more particularly to a method for manufacturing an aluminum fin material for a heat exchanger having excellent hydrophilicity.

BACKGROUND OF THE INVENTION Aluminum or aluminum alloys have excellent thermal conductivity, formability, and corrosion resistance, and are widely used as fin materials for heat exchangers.

By imparting hydrophilicity to the heat exchanger fin material made of aluminum or aluminum alloy and improving water wettability, ventilation resistance when used as a heat exchanger is reduced and thermal efficiency is improved. In some cases, noise reduction may be attempted.

Examples of such hydrophilic treatment methods include silicate treatment, boehmite treatment, alumite treatment, and the like.

Problems to be Solved by the Invention However, the above-mentioned processing method has the following two problems.

(a) Press oil during fin molding is easily removed during solvent degreasing, and remains on the fin surface to provide water repellency.

(b) When used for a long period of time in air conditioners, etc., oil in the air adheres to it and it becomes water repellent.

In particular, to explain the latter problem in more detail, when dew condenses on the fin surface while operating a heat exchanger that has undergone hydrophilic treatment (usually indoor units in cooling operation and outdoor units in heating operation). The fin surface exhibits hydrophilic properties, but if oil in the air adheres to it during drying operation where the fin surface does not condense, even if the fin surface is subsequently operated with dew condensation, the fin surface will be damaged due to the influence of oil contamination. There was a problem that it showed water repellency and did not have hydrophilicity. That is, in order to maintain hydrophilicity over a long period of time, a high level of hydrophilicity is required that allows water wettability even when the fin surface is contaminated due to repeated dew condensation and drying operations.

In view of the above-mentioned problems, the present invention has been developed to provide a high degree of hydrophilicity that does not deteriorate even if press oil during press molding cannot be completely removed, and even when repeated dew condensation and drying operations are performed when used as a heat exchanger. The present invention provides a fin material for a heat exchanger having hydrophilic interlocking.

Means for Solving the Problems The present invention solves the above problems by providing unsealed pores on the fin surface (here, unsealed pores are pressurized steam).

After applying an alumite treatment (without any general pore sealing treatment such as painting) and impregnating or filling the porous layer on the surface of the alumite layer with a surfactant,
This porous layer is subjected to a semi-sealing treatment (not a complete pore-sealing treatment, but a semi-sealed state in which the pores are slightly opened) by using pressurized steam or the like.

According to the present invention, the surfactant impregnated in the porous layer on the surface of the alumite layer gradually flows out to the fin surface through the semi-sealed fine pores, and due to the action of this surfactant, In order to remove press oil adhering to the fin surface or oil in the air when used as a heat exchanger, the fin surface must always be kept clean and free of oil, and degreasing after press molding is insufficient. Even if it is used as a heat exchanger for a long time, it can always maintain hydrophilicity with high water wettability.

EXAMPLE Hereinafter, an aluminum fin material for a heat exchanger manufactured by the method of the present invention will be described with reference to the drawings.

1 is an unsealed alumite fin that has been anodized in an oxalic acid or sulfuric acid bath, etc., and has an anodized alumite layer 3 on the surface of an aluminum fin material 2, and the surface is porous. It has a large number of holes 4a, 4b, 4c, . . . . 6 uses an unsealed alumite fin 1 and fills the holes 4a and 4b.
, 4c is impregnated or filled with a surfactant e such as an anionic alkylbenzene sulfonate or a polyoxyalkyl ether, and then the pores 4 are filled with pressurized steam or the like.
A, 4b, 4c, . . . are subjected to semi-sealing treatment until they are not completely sealed, resulting in fine holes 7a, 7b.

7c,...1. In other words, it is a semi-sealed alumite fin.

Semi-sealed alumite fin 5 configured as above
Even if oil remains on the fin surface due to insufficient degreasing during press molding, and even if oil in the air adheres to the fin surface after being used as a heat exchanger for a long time, fine particles may remain on the fin surface. The surfactant 6 sealed in the pores 7a, 7b, 7c, .

7b, 7c... In order to remove oil spilled onto the surface of the alumite layer 3 and attached to the surface of the aluminum fin 2, the surface of the aluminum fin 2 is left in an environment where it is contaminated by oil for a long period of time. Even if it is present, it has the effect of maintaining excellent hydrophilicity.

Next, the hydrophilic performance of the aluminum fin for a heat exchanger of the present invention was evaluated using the following hydrophilicity evaluation method.

Hydrophilicity evaluation method (1) Water wettability: Observe water repellency after immersing in water and taking out.

(It) Contact angle with water: Measured with a goniometer.

Types of samples Sample A: Aluminum fin as rolled to a thickness of 15ff and 1m; Sample B: 2 to 3 microns of sulfuric acid alumite was applied, followed by 6 open sealing treatment with pressurized steam.

Sample C: Processed according to the present invention Sulfuric acid alumite 2-3μ
Add a nonionic surfactant to the unsealed fin material.
, after impregnation with Oo1~1my/dm, 2
Semi-sealed for ~3 minutes.

As can be seen from the above table, Sample C according to the present invention has hydrophilic properties for a long period of time regardless of whether or not it is degreased after pressing.

Effects of the Invention As described above, the present invention applies unsealed alumite treatment to the fin surface, impregnates or fills the porous layer of the alumite layer with a surfactant, and then heats the porous layer with pressurized steam or the like. The pores are semi-sealed to the extent that they are not completely sealed, and regardless of the presence or absence of degreasing after press molding, it has excellent hydrophilic performance even when used as a fin material for heat exchangers for a long period of time. can.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main part of an unsealed fin subjected to alumite treatment, which is an intermediate stage of the method for producing an aluminum fin material for a heat exchanger according to the present invention, and Fig. 2 is a sectional view of the main part of an aluminum fin for a heat exchanger manufactured according to the present invention. It is a sectional view of the main part of the material. 2...Aluminum fin, 3...Alumite layer, 6...Surfactant.

Claims (1)

[Claims] After performing an unsealed alumite treatment on the surface of aluminum or an aluminum alloy, and after co-infiltrating or filling a surfactant into the porous layer on the surface of the alumite layer, the porous layer is semi-sealed using pressurized steam or the like. A method for producing aluminum fin material for heat exchangers.