JPS608422B2 - Manufacturing method of solar heat collector plate - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a solar heat collecting plate.

Solar heat collecting plates that use aluminum or its alloy as a substrate are lightweight, thermally conductive, have good formability, and have excellent selective absorption and durability on the surface due to electrolytic coloring properties. It is widely used in general because it has advantages such as forming scales.However, further requirements that are desired for this are as follows.
These include reducing costs, increasing strength and durability, and further improving the actual heat absorption efficiency transferred to the heat absorption tubes. The purpose of the present invention is to provide a method for manufacturing a heat collecting plate.

Therefore, this invention uses aluminum material as a means to form a good selective absorption film exclusively on the surface of L,
In order to meet various demands such as cost reduction and improvement of strength, durability, and effective heat absorption efficiency, the main purpose is to bond different metals that meet the above requirements to the aluminum material using adhesive to form a laminated board. It is something.

That is, this invention includes a process of anodizing a coiled aluminum foil (including aluminum alloy foil) and then electrolytically treating it in an aqueous solution containing a metal salt to form a selective solar energy absorption film on the surface, and this selection process. The gist of this invention is a method for manufacturing a solar heat collecting plate, which comprises a step of bonding an aluminum foil provided with an absorbing film to a dissimilar metal plate such as steel using an adhesive to integrate the two. The aluminum foil used as a material in this invention preferably has a thickness of about 5 to 500 mm.

If the thickness is less than 5, it is difficult to perform continuous electrolytic coloring using a coil, and on the other hand, if the thickness exceeds 500, it is difficult to expect the desired benefits of the present invention.
Particularly preferably, one having a thickness of about 100 mm is used. After this aluminum foil is subjected to continuous electrolytic coloring to form a selective solar energy absorption film on its surface, the type of dissimilar metal plate used as the base to which it is bonded is determined to match the type of solar heat collector plate to be obtained. It is selected mainly in response to the required requirements, and generally includes iron and copper.

When using iron, it is advantageous when the main focus is on improving economy and strength, and when using copper, it is advantageous to improve the actual heat absorption rate. This is advantageous when the main objective is to improve the efficiency of heat transfer to the heat absorbing tube (which is made of copper) and to improve the work crew based on the ease of welding with the heat absorbing tube. . The thickness of the dissimilar metal plate in the brackets is 1
It is suitable to set it to about 00 Buddha to 1 Yanagi. This plate thickness is 1
Making it thinner than 0.00 french is surprising since I was expecting the desired thickness of this invention.On the other hand, making it thicker than 1 yanagi will only increase the weight and increase the cost, which exceeds that. I cannot expect any special benefits from doing so. Particularly preferably, one having a thickness of about 600 peaks should be used.
The bonding of the above-mentioned dissimilar metal plates to the aluminum foil with an adhesive is carried out after the solar heat selective absorption film generation process. In order to avoid this, it is difficult to form a good selective absorption film on the aluminum surface due to dissimilar metals leaving the port.
It is possible to perform electrolytic treatment by masking the surface of the dissimilar metal plate in advance, but this has the drawback that the operation becomes somewhat troublesome.

However, the selective absorption film formed on the aluminum surface is
Since it is extremely thin and has low strength, it is easily damaged during the bonding process of dissimilar metal plates with an adhesive and the subsequent suction process. In order to prevent this, after electrolytically coloring the aluminum foil and before the above bonding, a synthetic resin protective film such as polyethylene or polypropylene is selectively applied to the absorbent film surface using a rubber pressure roll or the like. It is desirable that they be bonded together continuously so that they can be peeled off with pressure.
By the way, the electrolytic treatment conditions of the anodizing treatment and the metal salt electrolytic treatment performed on the coiled aluminum foil are not particularly limited in the present invention.

However, since this process is a continuous process using coil material as mentioned above, it goes without saying that it is desirable to be able to process it in as short a time as possible.Based on this request, various experiments were carried out. According to the research results, as the electrolytic treatment in each of the above steps for selectively absorbing membrane production, the first step of anodizing treatment is particularly performed in a phosphoric acid aqueous solution with a liquid concentration of 50% or more. in,
And the liquid temperature shall be maintained at 35 to 80 degrees.
In addition, the second step of metal salt treatment for blackening the film is that the concentration of metal salt in the electrolytic solution is not suitable for conventional electrolytic treatment.
Relatively higher concentration than the solution concentration, for example, 50 to 200 m/s for nickel salt, 50 to 200 m/s for cobalt salt, 15 to 10 m/s for saving salt,
In a metal salt aqueous solution with a concentration of 5 to 50 min/night for tin salts and 5 to 50 min/night for iron salts, and at a high temperature,
It is preferable that the temperature is maintained at 5 to 85 oC'. According to these processing conditions, ``the total processing time for both steps is about 1 to 5 minutes,'' and the film thickness t = 1 French or less, absorption rate = 0.9 or more, emissivity 2 = 0.1 or less. A solar heat selective absorption film having excellent selective absorption performance can be produced.

The reason why it is especially preferable to use a phosphoric acid aqueous solution as the electrolyte in the anodizing process is that the film that can be formed is thinner than when using an aqueous solution such as sulfuric acid or oxalic acid.
Moreover, it is possible to obtain a membrane with large micropores, and as a result, the amount of metal precipitated can be increased, resulting in an even better selective absorption membrane.

Conventional general treatment conditions for anodizing using a phosphoric acid aqueous solution are ~liquid concentration 20~30, Tanoguchi liquid overflow 20~300
0 "Current density 0.2-0.4 A nod co-Q.C"
The processing time was already about 15 minutes. Even compared to such conventional general processing conditions, the above liquid concentration and liquid temperature are set to considerably higher values. Considering the condition, it is thought to be around 8002.
On the other hand, if the concentration is less than 50%, it will take a long time to obtain the required film thickness, and a stable film cannot be obtained in a short period of time.
It has 3002 sleeves. Furthermore, ``the liquid temperature is determined by the relative relationship with the liquid concentration, but if it is less than 35℃, it will take a long time to obtain the required oxide film thickness, and a stable film will not be obtained. If the temperature exceeds 80 oo, the dissolution effect of the film becomes large, making it difficult to obtain the required film thickness, and resulting in a powdery milky white film.Relationship between liquid concentration and temperature To show the relative preferable range, the concentration is 70 to 150 to 45 overflow.
A range of approximately 55 oo is preferable. Furthermore, ``In the metal salt treatment for blackening the film, the concentration and temperature of the aqueous solution containing the metal salt are set within the above ranges.'' If they are both below the lower limit, a good selective absorption film will be formed. However, if the concentration exceeds the upper limit, the cost will increase, the colorability will deteriorate, making it difficult to form a good selective absorption film, and if the temperature exceeds the upper limit, it will be difficult to form a good selective absorption film. This is because the dissolving action of the film increases, making it impossible to obtain a good selective absorption film.

A particularly preferred concentration range for nickel salts is 80 to 1
30 evenings/Z, 80 to 130 tanos in cobalt salt,
30-5G tanoso in copper salt, 15-3 in tin salt
It is preferably in the range of 60 to 10 M/day for iron salt, and the temperature is particularly preferably in the range of 40 to 60 o'clock.
To further explain the method of the present invention based on the illustrated embodiment, reference numeral 1 is a coiled aluminum foil, which is continuously desalted and first introduced into a pretreatment section 2 where it is subjected to pretreatment such as predetermined degreasing. give

This is then led to the next anodizing section 3, where it is anodized using an aqueous solution of sulfuric acid, oxalic acid, phosphoric acid, etc. as an electrolyte to form a porous anodic oxide film on the surface of the aluminum foil. Next, the aluminum foil on which this oxide film has been formed is led to the next electrolytic coloring treatment section 4, where an aqueous solution containing one or more metal salts such as nickel salt, copper salt, tin salt, cobalt salt, iron salt, etc. An electrolytic treatment is performed as an electrolytic solution, and metal is precipitated and filled into the fine pores of the oxide film to form a blackened solar heat energy selective absorption film on the aluminum surface. Next, after drying this to some extent, it is guided to a natural roll coater for applying adhesive, which has an aluminum foil placed next to it, and the adhesive is applied using this.

As for the roll coater, it is preferable to use a gravure roll with a thickness of 60 to 15 mm, and as an adhesive, it is preferable to use a gravure roll with a
Resin-based materials having a heat resistance of 0 or more are preferred, and for example, silicone resin, silicone rubber-based, polyamide resin-based, and acrylic resin-based materials are optimal. If the adhesive is a dry adhesive type, the aluminum foil coated with adhesive is then guided to a drying zone (not shown) to dry; if the adhesive is a wet adhesive type,
The above drying step is omitted and the sheet is continuously guided between the next pair of rubber pressure bonding rolls 5, 5, and at the same time, a dissimilar metal plate 6 such as iron or copper formed into a coil shape is fed out and the above pressure bonded at the same time. This is guided into a roll and laminated on the back side of the aluminum foil to obtain the desired solar heat collecting plate 7 as an integrated laminated plate. After the above bonding, if the adhesive used is a curing type, it is further led to a drying zone for curing. Of course, if the adhesive is a type that dries at room temperature, such a curing step is not necessary. The solar heat collecting plate manufactured in this manner is subjected to predetermined processing and shaping for attaching heat absorption tubes, etc., and is then cut into predetermined dimensions to produce a final product. According to the present invention, as described above, since the base material of the solar heat collecting plate is composed of dissimilar metal plates such as iron and copper on which aluminum foil is bonded, the type of the dissimilar metal plates is determined. By selection,
Compared to solar heat collector plates that are made only of aluminum material,
It becomes possible to arbitrarily obtain a solar heat collecting plate that is more excellent in economy, strength, durability, substantial heat absorption efficiency, workability, etc.

Moreover, since the selective absorption film is formed by electrolytic treatment of a single coiled aluminum foil, it is possible to form a selective absorption film with excellent selective absorption performance continuously and with high efficiency. After processing, the aluminum foil is bonded to a dissimilar metal plate and integrated with it, resulting in a highly efficient solar heat collection plate that has excellent selective absorption of solar heat energy but is comparable in terms of strength. be able to.

[Brief explanation of drawings]

The drawings are block diagrams illustrating embodiments of the invention. 1...Aluminum foil, 3...Anodizing treatment section, 4...Electrolytic coloring treatment section, 5...Crimping roll, 6...Different metal plate, 7...... ...Solar heat collector plate.

Claims (1)

[Claims] 1 After anodizing the coiled aluminum foil,
The process involves electrolytically treating the surface in an aqueous solution containing metal salts to form a film that selectively absorbs solar energy on the surface, and then bonding the aluminum foil with this selective absorption film to a plate of dissimilar metals such as iron or copper. A method of manufacturing a solar heat collector plate that includes an integrated process.