JPS618594A - Heat pipe and method of corrosion preventive treatment of inner surface thereof - Google Patents

Abstract

PURPOSE:To make it possible to prevent the pipe inner surface of a heat pipe that uses water as operating fluid from being attacked, by forming an oxidized film on the inner surface of an iron type pipe, and providing the inner surface with a wick. CONSTITUTION:A closed cylindrical vessel 1 is made of a metal material mainly of iron such as carbon steels, chrome-nickel steels, chrome-nickel base stainless steels, etc. The wick is made of a nonwoven fabric of metal fiber, organic fiber, or inorganic fiber, a metal mesh, or a porous sintered body produced from a metal powder, which is pressed or baked onto the inner surface of the pipe. The heat pipe uses water is operating fluid and the pipe is made of an iron type metal. To prevent the iron type metal from being attacked, the inner surface is formed with a corrosion preventive oxidized film 3.

Description

Detailed Description of the Invention (Field of Application in the Ordinary Industry) The present invention relates to heat nozzles, particularly iron-based heat nozzles, and heat nozzles whose inner surfaces are anti-corrosive by oxidation treatment, and which use water as a working fluid. The present invention relates to the processing method.

(Prior Art) Heat pipes have recently been created as a means of effectively utilizing heat.

Most typical heat pipes use an organic compound vIJ such as alcohol9, while some use water.

In addition, most of the heating materials were copper-based, with only some iron-based materials being used.

(Problems to be Solved by the Invention) Most of conventional heat pipes that use organic solvent-based working fluids decompose at temperatures around 200°C, so they cannot be used at temperatures higher than this. Although heat pipes using water as a working fluid can be stably used at temperatures ranging from room temperature to about 300°C, they did not find that there were no problems with the Nozoib material.

That is, conventionally used copper heat pipes have a high risk of breaking due to the high vapor pressure of water, and have poor pressure resistance. Therefore, we would like to use a heat pipe made of iron or a ferrous material such as steel, but due to the contact reaction between water and the ferrous material, if the heat pipe is operated for a long time, hydrogen gas will be generated, which will lead to corrosion of the pipe. Whatever it is, it ends up being destroyed.

Therefore, we can solve all these problems and create water for heat source! l1l
J? It has been desired to develop a heat nomi-ib that does not cause corrosion.

(Means for solving all 74 problems) The present invention has been made in view of the above considerations, and an oxide film is completely formed on the inward side of the iron-based pipe.

In manufacturing the heat pipe (first invention) which is fully water-operated, the inner surface of the iron-based heat pipe is treated with a dilute solution of sodium sulfur (Na2S) to completely form a film. The present invention relates to a method (second invention) and a method (third invention) of treating the inner surface of an iron-based heat pipe with a mixed aqueous solution of sodium chlorite and sodium hydroxide to completely form an oxide film.

(Function) By forming a dense oxide film on the inner surface of the iron-based e-beam, corrosion of the inner surface of the pipe can be prevented when water is used as the working fluid (first invention). ,
In manufacturing heat pipes, a dense oxide film can be formed on the inner surface of iron-based pipes by chemical treatment, which is inexpensive and has little risk. (Second and Third Inventions) (Example) Fig. 1 is an explanatory diagram of the operation of the heat nomi-ive, and Fig. 2 is a cross-sectional view of the heat pipe according to the present invention.

First, in Fig. 1, 1 is a sealed cylindrical container, 2 is a wick, and is heated in the direction of the arrow Qii, so that the 1 working fluid evaporates and the vaporized material moves to the right, becoming condensed liquid by cooling (heat exchange) in Q2. moves to the left.

The non-invention here is that the sealed cylindrical container 1 is made of iron or carbon steel.

Metal materials whose main component is iron or gold, such as chromium-nickel steel or chromium-nickel stainless steel.

In addition, Quick is a variety of metal fibers, organic fibers, inorganic fibers, non-woven fabrics, and metal mesh bodies.

It is manufactured by subjecting the inner peripheral surface of a porous sintered body of metal powder, etc., to a process such as crimping or baking.

In the present invention, in such a heat treatment, the working fluid is gold water, and the pipe is made of carbon steel.In order to completely prevent corrosion of the iron metal, the inner surface is coated with an oxide film 3. It is made of anti-corrosion material. (1st
In this case, one of the anti-corrosion measures is the method of using a sulfide film forming agent (the second invention).
NazS) PH13-I in the concentration range of 0.01-1%
The nozzle is heated at room temperature by immersing it in a hot bath at room temperature to 60°C in an alkaline solution such as sodium carbonate with a strength of about N, or by filling this treatment agent into the pipe that forms the heat pipe. The heat pipe is immersed in a hot bath of ~60°C to cause a sufficient reaction, and an oxide film is formed on the inner surface of the heat pipe.

Another method is to use oxide film forming agent sound (third invention)
A pipe constituting a heat pipe is placed in a bath solution heated to 50 to 80°C of a mixed bath solution containing chlorite (1 to 5%) and hydrated sodium (1 to 5%). or fill this processing agent into this noquizo, and
The pipe is heated and immersed in a hot bath of ~80°C to react and form an oxide film on the surface of the heat pipe (c).

In any of the above treatments, the reaction time is approximately 1 hour, followed by washing with water and drying.

We oxidized the circular surface of the iron pipe as a sample using these two methods, and compared the hydrogen gas generation and suppression effects using unoxidized iron pipe and gas chromad analysis.

As an example of the results, the untreated circular iron pipe shown in Fig. 3 has a significant H2 peak, but the oxide film (sulfide film) pipe produced by the method of the present invention is The oxide film pipes all have low H2 peaks, hardly any hydrogen gas is generated, indicating that they are difficult to corrode under long-term water working fluids.

(Effects of the Invention) As described above, the present invention provides a heat nozzle which uses water, which is the most universal and inexpensive material, and which does not easily cause internal corrosion even when an iron-based material is used as the pipe base material. In addition, we provide a chemical treatment method that is extremely simple and easy to handle for this internal corrosion protection.

4. 111 of the drawings Figure 1 is an explanatory diagram of the operation of the heat pipe, Figure 2 is a cross-sectional view showing an example of the heat pipe according to the present invention, and Figure 3 is a gas chromatogram of the circular surface of the heat pipe.・For example, (
(a) is for iron-based pipes that have not been treated inward, (b) is for iron-based pipes with an oxide film (sulfide film) on the inner surface, and (c)
considers the case of an iron-based knob with an oxide film on its circular surface.

1... Closed cylindrical valley device, 2... Wick, 3... Oxide film.

Agent: Patent Attorney Mamoru Takeuchi Figure 2 (b) Figure 3 (c)

Claims (3)

[Claims] (1) A heat pipe characterized in that an oxide film is formed on the inner surface of the iron-based pipe, a wick is provided on the inner surface, and water is used as a working fluid. (2) Sodium sulfide (Na_2) was added to the inner surface of the iron-based heat pipe.
S) A method for anticorrosion treatment of heat pipes, which comprises forming an oxide film by treating at room temperature to 60° C. with an alkaline solution having a pH of about 13 to 1N at a concentration range of 0.01 to 1%. (3) The inner surface of the iron-based heat pipe is treated with a mixed aqueous solution of 1-5% sodium chlorite and 1-5% sodium hydroxide at 50-80°C to form an oxide film. Corrosion prevention treatment method for heat pipes.