JP3029522B2 - Hydrophilic metal heat transfer material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow in which a fluid flows down on one side of a heat transfer surface in an absorption refrigerator, an absorption chiller / heater and the like while spreading in a film form, and exchanges heat with the fluid flowing on the opposite side. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal heat transfer material used for a liquid film heat exchanger and the like, which has excellent hydrophilicity and is less likely to deteriorate in hydrophilicity.

[0002]

2. Description of the Related Art A falling film heat exchanger such as an absorption refrigerator has a liquid flowing down on one side and exchanges heat with a fluid on the other side. For this reason, the material used for the falling liquid film type heat exchanger is required to have wettability and spreadability of the surface, that is, hydrophilicity. If the hydrophilicity is poor, the heat transfer performance of the heat exchanger is reduced. Therefore, usually, in this type of heat exchanger, a product is shipped after a test operation and a running-in operation for several days to confirm a predetermined performance.

[0003] On the other hand, this kind of metal heat transfer material is drawn and processed.
At the time of plastic working such as rolling processing or cutting work, processing oil such as drawing oil or rolling oil adheres to the surface, and when heat treatment is performed after processing, the hydrophobic groups [-CH] such as residual oil remaining are removed. The organic substances and the like that adhere to the surface. Therefore, as a material subjected to the following treatment, the time for trial operation and break-in operation has been reduced.

(1) Material subjected to mechanical polishing treatment The surface of a metal material is polished with a wire brush or sandpaper to remove organic substances and the like adhering to the material surface, thereby improving the surface hydrophilicity. Material. Alternatively, in order to further improve the hydrophilicity, the material is washed with an organic solvent or the like and then subjected to the above polishing treatment.

(2) Tubes subjected to surface chemical treatment A material whose surface hydrophilicity is improved by cleaning and activating the surface with sulfuric acid and a surfactant.

[0006]

However, since the material subjected to the above-mentioned hydrophilic treatment has a somewhat improved hydrophilicity, the time required for the trial operation and the break-in operation of the heat exchanger can be shortened somewhat, but the predetermined performance is not improved. In order to start the operation, a long time of trial operation and running-in operation was required. Further, those using the above-mentioned material subjected to the hydrophilic treatment have a disadvantage that the hydrophilicity is rapidly deteriorated as time passes.

[0007] Therefore, when the material is stored for one month or more before being incorporated into the heat exchanger, the above-mentioned test operation time is further extended due to deterioration of hydrophilicity with time.

In view of the above problems, the present invention provides a hydrophilic metal material which is excellent in surface hydrophilicity, has little deterioration over time, has excellent heat transfer performance, and can contribute to shortening of a trial run time. It is intended to do so.

[0009]

Means for Solving the Problems As a means for solving the above-mentioned problems, the present invention relates to a method for analyzing the organic matter remaining on the surface by X-ray spectroscopy. The gist of the present invention is a hydrophilic metal heat transfer material characterized by being larger than the peak spectrum intensity of the group [-CH], or further having an oxide film having an average thickness of 300 to 1400 ° on the surface.

In another aspect of the present invention, when an organic substance remaining on the surface is analyzed by X-ray spectroscopy, the peak spectral intensity of the hydrophilic group [—C ＝ O] is larger than the peak spectral intensity of the hydrophobic group [—CH]. In addition, the ratio of the peak spectrum intensity obtained by adding the peak spectrum intensities of the hydrophilic group [-C = O] and the hydrophobic group [-CH] to the peak spectrum intensity of X-ray spectroscopic analysis of copper ｛[-C = O] + [ -CH]｝ / Cu is less than 1, or the surface has an average thickness of 30
A gist is a hydrophilic copper or copper alloy heat transfer material having an oxide film of 0 to 1400 °.

[0011]

[Action]

Hereinafter, the present invention will be described in more detail.

In the present invention, when an organic substance remaining on the surface of a metal material is subjected to X-ray spectroscopy (XPS),
The peak spectral intensity of the hydrophilic group [-C = O] is larger than the peak spectral intensity of the hydrophobic group [-CH].

During processing such as plastic working or cutting of a material, processing oil such as drawing oil, rolling oil, cutting oil, etc. adheres to the surface, and has conventionally been removed from the material surface by means of washing or the like. ing. Since these organic substances have a hydrophobic group [—CH] and are hydrophobic, it is necessary to completely remove these organic substances in order to obtain hydrophilicity. However, these organic substances slightly remain in ordinary industrial production. There was a tendency.

The inventor of the present invention has conducted intensive studies on measures to obtain good hydrophilicity without completely removing the residual organic substances. It has been found that the material has been changed from hydrophobic to hydrophilic, and that this material exhibits good hydrophilicity. That is, even if an organic substance remains on the material surface, it is converted from hydrophobic [—CH] to hydrophilic [—C ＝ O], so that even if there is a residual organic substance as compared with the conventional material, the organic substance remains hydrophilic. Has been found to be excellent.

The fact that the altered organic substance has hydrophilicity can be confirmed by performing X-ray spectroscopy analysis. The peak spectral intensity of the hydrophobic group [-CH] on the surface before the corona discharge treatment is determined by the hydrophilic group [-C = O], and conversely, the peak spectral intensity of the hydrophilic group [—C ＝ O] on the surface after the treatment is larger than the peak spectral intensity of the hydrophobic group [—CH].

Further, according to the present invention, the organic matter on the surface has hydrophilicity as described above, and the peak spectral intensity of the hydrophilic group [-C = O] and the hydrophobic group [-CH] in the X-ray spectroscopic analysis. Ratio of the sum of peak spectral intensities to the peak spectral intensity of copper {[-C = O] + [-CH]}
/ Cu is less than 1, that is, the residual organic substance has hydrophilicity, and the hydrophilic group [-C = O]
And the hydrophobic group [—CH] is small, the hydrophilicity is further improved.

Further, in the present invention, in order to maintain the hydrophilicity for a long time, it is effective to attach a predetermined amount of an oxide film.

Although the oxide film itself has hydrophilicity, it has a function of covering the active metal surface and preventing adsorption of dirt in the atmosphere, and is scattered in a stable and porous state. Hard to receive. The average thickness of this film is suitably 300 to 1400 °. That is, when the average thickness of the film is smaller than 300 °, the metal background is exposed in some places, and the aging of the hydrophilic property is likely to occur. For this reason, the average thickness needs to be larger than 300 °. However, although it is better that the average thickness of the oxide film is thick, even if the thickness exceeds 1400 °, the effect of improving the deterioration with time is not so large, and the productivity is rather lowered. Therefore, it is appropriate that the thickness of the oxide film is 300 to 1400 °. Here, the average film thickness means a thickness of a surface oxide film measured by a cathode reduction method described later in Examples.

Next, an embodiment of the present invention will be described.

[0021]

【Example】

Phosphorous deoxidized copper tube having an outer diameter of 16 mm and a wall thickness of 0.6 mm
Using a smooth tube of (JISC1201), dissolution as a process →
A copper tube was manufactured by the steps of extrusion → rolling → drawing → annealing → drawing. This was subjected to corona discharge or brush polishing as a surface treatment, and a part of the material was subjected to pretreatment to obtain test materials. Table 1 shows the processing conditions.

The corona discharge was carried out at a power of 830 W and 1500 W at a line speed of 5 m / min and 10 m / min using the apparatus shown in FIGS. A voltage is applied to a metal outer tube 2 provided with an insulating body tube 1 and a test material (copper tube) 1 which is brought into contact with the installation rolls 4a and 4b and passes through the metal outer tube at a fixed distance and is provided with a corona. This is to generate electric discharge. On the other hand, for brush polishing, the wire diameter was 0.8m.
The treatment was performed at a line speed of 10 m / min using a m brush.

Among the comparative examples, comparative examples 1 and 2 were also manufactured by immersion cleaning in an organic solvent as a pretreatment for brush polishing. Among the inventive examples, inventive examples 5, 6, and 7 were also manufactured by performing a heat treatment at 300 ° C. for 8 minutes in an inert atmosphere as a pretreatment for corona discharge.

With respect to the surface treatment state of these test materials, an X-ray photoelectron spectrometer was used to measure an area of 1000 μm ² at an output of 300 W and a molecular bond energy ｛[−C = O], The status of [-CH]} is determined by a counter of an X-ray spectrometer to determine the peak count, and the peak count of {[-C = O] + [-CH]} is obtained.
Intensity ratio to the peak count number of Cu ｛[-C = O] +
[-CH]｝ / Cu was calculated. Table 2 shows the results. FIGS. 1 and 2 show the spectra of some test materials.

The oxide film thickness was measured using a copper tube as a cathode and a cathode reduction method. That is,
A copper tube is put into a 0.1N potassium chloride aqueous solution, the current is set to be constant by using the copper tube as a cathode, and the time until the voltage no longer changes is measured. did. Table 2 shows the results.

Table 3 shows the results of the evaluation of the hydrophilicity of each surface condition immediately after the treatment and after the lapse of a predetermined period of time for the surface-treated copper tube.

Here, for the evaluation of hydrophilicity, 2 cc of water was dropped from the upper surface of the copper tube by 20 mm with a syringe, and the state of spreading of the water was observed by leaving it for 5 seconds. The evaluation criteria were as follows: water adhered in a thin film state for 5 seconds after dropping, ◎ (excellent) if there was no shrinkage of water, ○ (good) if there was a slight increase in film thickness after dropping, shrinkage partially When it occurred, it was evaluated as △ (somewhat inferior), and when it shrunk as a whole and became granular, it was evaluated as x (inferior).

FIG. 1 shows the spectrum of an organic substance remaining on the surface of the test material (corona discharge only) of Example 2 of the present invention. The peak of the molecular bond energy, which is the spectrum of the hydrophilic group [—C ＝ O], at about 289 eV. And a hydrophobic group [-C
H] has a molecular binding energy of about 285.
It shows a peak at eV. And the hydrophilic group [-C
= O] peak spectral intensity (count about 6400)
Is larger than the peak spectrum intensity of the hydrophobic group [-CH] (count number: about 2800). This indicates that Example 2 of the present invention has high hydrophilicity.

On the other hand, FIG. 2 shows the test material of Comparative Example 1 (+
(Brush polishing) is a spectrum of an organic substance remaining on the surface, and shows a peak at a molecular binding energy of about 285 eV, which is a spectrum of a hydrophobic group [-CH], and a molecular binding energy, which is a spectrum of a hydrophilic group [-C = O]. Shows a peak at about 289 eV. Then, the peak spectral intensity of the hydrophobic group [-CH] (count number of about 5
500) is the peak spectral intensity of the hydrophilic group [-C = O].
(Count number about 1700). This indicates that Comparative Example 1 is inferior in hydrophilicity to Invention Example 2. That is, it can be seen that all of the examples of the present invention have high hydrophilicity, and all of the comparative examples have high hydrophobicity.

As shown in Table 3, it can be seen that each of the copper tubes of the present invention has a large hydrophilic property and good wettability. In particular, in Examples 1, 2, and 3 of the present invention, which show excellent hydrophilicity at the initial stage, the degree of hydrophilicity is reduced to some extent with the lapse of time, but the hydrophilicity and the XPS intensity ratio [[-C = O] + [-CH]｝ / Cu
In Examples 4, 5, 6, and 7 of the present invention having an oxide film having a thickness smaller than 1 and a predetermined thickness, even after 120 days from the treatment, hydrophilicity did not deteriorate due to a synergistic effect.

On the other hand, in the comparative examples, the hydrophobicity was high in all cases, and the one polished by brushing after washing as a pretreatment was slightly better immediately after the treatment, but the performance deteriorated with the passage of time.

Further, when Examples 4 and 5 of the present invention are compared, XP
The result that the S peak intensity ratio {[-C = O] + [-CH]} / Cu and the oxide film (Å) are almost equal was obtained. By applying heat treatment as a pretreatment as the processing condition of Example 5 of the present invention, the corona discharge condition can be set to a discharge output of 1500 W and a line speed of 10 m / min. 5m /
The line speed can be doubled compared to the minute and the productivity is improved.

These results can be clarified also from the difference in heat transfer performance. That is, since the higher the hydrophilic property, the higher the heat transfer performance, the heat transfer performance evaluation test was carried out one day after the treatment with respect to Example 2 of the present invention and Comparative Example 1 after the treatment.

As a method of performance evaluation, a copper tube treated as described above was attached to an evaporator of an absorption refrigerator as a type of a falling film heat exchanger, and an evaporation temperature of about 4 ° C. and a cold water flow rate of 1. 5m /
The test was performed under the conditions of s and the amount of refrigerant sprayed from 0.75 to 1.25 kg / (m · min). The result is shown in FIG.

As shown in FIG. 3, the copper tube of the present invention example 2
An improvement of about 13% in performance was obtained as compared with Comparative Example 1, which indicates that the hydrophilic treatment material according to the present invention has excellent hydrophilicity.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

In the above embodiment, the corona discharge treatment is used as the surface treatment. However, a plasma discharge treatment may be performed instead of the corona discharge treatment, or a heat treatment in an oxidizing atmosphere may be effective as a pretreatment. is there.

In the above embodiment, a copper tube is shown as a metal heat transfer material. However, in the present invention, the material is not limited, and the invention can be applied to aluminum, iron, stainless steel and the like. Further, the shape of the heat transfer material is not limited to a pipe, and can be used for a plate material, a mold material, and the like. The pipe can be applied not only to the outer surface but also to the inner surface. In addition, the present invention can be applied not only to a smooth surface but also to a shape such as a corrugated surface having irregularities.

[0042]

As described above in detail, the metal heat transfer material according to the present invention exhibits excellent hydrophilicity, so that it is possible to shorten the time for trial operation and running-in of the heat exchanger, and to store the heat exchanger for a long time. No decrease in hydrophilicity occurs even afterwards. Therefore, it is extremely useful, for example, in a falling film heat exchanger requiring hydrophilicity.

[Brief description of the drawings]

FIG. 1 is a spectrum diagram of an organic substance remaining on the surface of a test material of the present invention 2 (corona discharge only).

FIG. 2 is a spectrum diagram of organic substances remaining on the surface of a test material (washing + brush polishing) of Comparative Example 1.

FIG. 3 is a graph showing the evaporation performance of an absorption refrigerator to which a test material obtained in an example is applied.

FIG. 4 is a schematic view showing an outline of a corona discharge treatment apparatus used in the embodiment.

FIG. 5 is a sectional view of the electrode shown in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulated body tube 2 Metal outer tube 3 Test material (metal tube) 4a, 4b Grounding roll 5 Electrode 6 Transformer 7 Oscillator 8 AC power supply

Claims (3)

(57) [Claims] An organic substance remaining on the surface is converted into a hydrophilic group.
When the organic substance remaining on the surface of the metal heat transfer material subjected to the hydrophilic treatment for transforming the surface into a hydrophilic substance is analyzed by X-ray spectroscopy, the peak spectral intensity of the hydrophilic group [-C = O] is changed to the hydrophobic group [-C
H], which is higher than the peak spectrum intensity. 2. The method according to claim 1, wherein the hydrophobic group of the organic substance remaining on the surface is converted to a hydrophilic group.
Made of copper or copper alloy subjected to hydrophilic treatment
In the heat transfer material of the genus, when the organic matter remaining on the surface is analyzed by X-ray spectroscopy, the peak spectral intensity of the hydrophilic group [-C = O] is larger than the peak spectral intensity of the hydrophobic group [-CH], and the hydrophilic group [ -C = O] and the ratio of the peak spectral intensity obtained by adding the peak spectral intensity of the hydrophobic group [-CH] to the peak spectral intensity of the X-ray spectroscopic analysis of copper ｛[-C =
O] + [- CH]} / Cu hydrophilic metal heat transfer material, characterized in that less than 1. 3. A hydrophilic metallic heat transfer material according to claim 1 or 2, characterized in that it has an oxide film having an average thickness of 300~1400Å the surface.