JPS6136156B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for processing the end of a leaded heat pipe that improves workability.

In general, a heat exchanger for waste heat recovery using a heat pipe places the heat absorption side of the heat pipe in a duct where high-temperature waste gas flows, and the heat radiation side of the heat pipe in a duct where clean air or low-temperature gas flows. It is being done to collect waste heat.

However, when fuel oil containing sulfur is used, the combustion gas contains sulfur oxides (SOx),
When this waste gas comes into contact with the heat pipe and its temperature drops below the sulfuric acid dew point, sulfuric acid is produced on the surface, which causes corrosion.

For this reason, the present inventors have previously developed and proposed a method for manufacturing a lead-covered heat pipe in which the outer pipe is coated with lead or a lead alloy having excellent sulfuric acid dew point corrosion resistance.

In this method, semi-molten lead or lead alloy is placed around the outer periphery of a pre-formed heat pipe, which serves as an inner pipe, through a lead-covered machine that combines a nipple and a die, with both ends protruding from the heat pipe. Coat and solidify. Next, the formed leaded heat pipe is mounted on a rotary table and rotated while pressing a spatula against both ends of the protruding lead outer tube to perform a spatula drawing process, and then the small hole in the center of the drawn pipe is sealed. It is.

However, in this method, the end of the leaded heat pipe is drawn by a spatula drawing process, so the feed of the spatula must be adjusted sequentially to form it into a hemispherical shape.Moreover, centering is time-consuming, which reduces work efficiency. It was extremely bad. In addition, in the spatula drawing process, the leaded heat pipe is attached to a rotary table and rotated, so in the case of a particularly long heat pipe, a large rotary table is required, work efficiency is poor, and long heat pipes are rotated. leaded heat pipes were difficult to manufacture.

In view of these conventional drawbacks, the present invention has been developed as a result of various researches, and as a result, the present invention has developed a method for processing the end of a leaded heat pipe, which improves the workability of drawing and makes it possible to manufacture long leaded heat pipes. This is what we discovered.

That is, in the method of the present invention, semi-molten lead or lead alloy is passed through a heat pipe that serves as an inner tube through a leaded machine that combines a nipple and a die, and the semi-molten lead or lead alloy is passed into the outer tube.
After the coating was solidified so that both ends thereof protruded from the heat pipe, a concave circular die was pressed against both ends of the protruding lead outer tube of the formed leaded heat pipe, and drawing processing was performed. It is characterized by sealing the small hole in the center.

Hereinafter, the method of the present invention will be explained in detail with reference to the drawings.

1 to 7 show one method of the present invention. First, as shown in FIG. 1, a metal with open ends, such as copper, copper alloy, aluminum, aluminum alloy, carbon steel, or alloy steel, Prepare a tube and call it inner tube 1. As shown in FIG. 2, a circular cap 2a is brazed to one open end, and a cap 2b having an injection capillary 3 is brazed to the other open end.

Next, this injection tube 3 is connected to a vacuum pump (not shown) to deaerate the inside of the inner tube 1, and then a working fluid 4 such as water or chlorofluorocarbon is sealed inside, and then the injection tube 3 is sealed off. A heat pipe 5 as shown in FIG. 3 is formed.

The heat pipe 5 thus obtained is passed through a leaded machine 8 that combines a nipple 6 shown in FIG. lead or lead alloy9
After covering and solidifying the lead outer tube 9, it is passed through a water-cooled die 7 to adjust the thickness to a predetermined thickness. Furthermore, this tip side is cooled with water using a shower 10 to complete the lead coating while cooling the heat pipe 5, so that both ends of the lead outer tube 9 protrude from both ends of the heat pipe 5 as shown in FIG. Form. Also, during this leaded processing, the heat pipe 5 is heated by contacting the high temperature lead or lead alloy 9a, but the tip side is heated by the shower 1.
Since the heat pipe 5 is cooled with water, the entire body is cooled by the rapid heat transfer action of the heat pipe 5, and damage to the heat pipe 5 and poor adhesion between the inner tube 1 and the outer lead tube 9 can be prevented.

Next, the leaded heat pipe 1 formed as described above
1 to a support stand (not shown) and fix it.
A concave circular die 12 is rotated and pressed against both ends of the lead outer tube 9 protruding from the heat pipe 5 to perform a drawing process. This concave circular die 1
2 is a tapered part 12a formed to smoothly enter the die even if the end of the lead outer tube 9 is slightly bent or deformed, and to prevent blisters from occurring in the lead outer tube 9 during drawing processing. Parallel part 12b provided for
and a concave curved surface part 1 finished in a hemispherical shape with protruding ends.
2c, and an air vent hole 12d at the base end to quickly vent air during drawing.
is provided.

After drawing both ends of the leaded outer tube 9 with the concave circular die 12 in this way, the small hole 13 formed in the center of the drawn portion is sealed to form a leaded heat pipe as shown in FIG. Complete 11 terminal processing. The small hole 13 may be sealed by a gas welding method using lead or a lead alloy as a brazing material, a welding method using an electric soldering iron, an ultrasonic welding method, a pressure welding method, a lead plug press-in method, etc., which have good airtightness. Any method may be used as long as it is sealed.

Therefore, according to the present invention, since the end is drawn by pressing the concave circular die 12 which has a concave curved surface in advance to obtain the finished shape, the core of the leaded heat pipe is Since there is no need to strictly carry out unloading, and there is no need to adjust the feed of the spatula, the end can be processed in a short time and with high precision. In addition, in the above method, the leaded heat pipe 11 is fixed to the support base and the concave circular die 12 is rotated, so there is no need to provide a rotation drive mechanism on the support base, which is particularly suitable for manufacturing a long leaded heat pipe 11. Not only is it effective, but it also does not damage the soft lead outer tube 9, so it can be of excellent quality.

In addition, in the above explanation, a method was shown in which the leaded heat pipe 11 is fixed to a support base and the concave circular die 12 is pressed while rotating, but this method is different when the leaded heat pipe 11 is short. Conversely, a method may also be used in which the leaded heat pipe 11 is rotated and the concave circular die 12 is pressed against it.

Next, specific examples of the present invention will be described. A heat pipe 5 was prepared by using a copper tube with an outer diameter of 25.4 mmφ and a length of 1.5 m as the inner tube 1, attaching caps 2a and 2b to both ends thereof, and sealing water as the working fluid 4. This heat pipe 5 is passed through a leaded machine 8, and a lead alloy (Pb-1.3% by weight Sn-
The lead outer tube 9 was coated with lead (0.1% by weight Sb) so that both ends of the lead outer tube 9 protruded as shown in FIG. Next, this leaded heat pipe 11 is fixed to a support base, and the concave circular die 12 is rotated and pressed against both ends of the lead outer tube 9 to draw it. The hole 13 was sealed by gas welding using a lead rod, and the end processing was completed.

In this way, the method using the concave circular die 12 can reduce the machining time to about 1/5 compared to the conventional end machining method using a spatula drawing process, and has excellent workability and high accuracy. The drawing process could be carried out, and no harmful damage was observed in the lead outer tube 9 of the lead-covered heat pipe 11 obtained.

As explained above, the method for processing the end of a leaded heat pipe according to the present invention not only improves the workability of the end processing by drawing, but also makes it possible to manufacture particularly long leaded heat pipes. It is effective.

[Brief explanation of the drawing]

Figures 1 to 7 show the method of the present invention step by step, in which Figure 1 is a sectional view of the inner tube, Figure 2 is a sectional view of the inner tube with the cap attached, and Figure 3 is the heat treatment method. A cross-sectional view of the pipe, Figure 4 is a cross-sectional view of the leaded machine showing the state in which the heat pipe is leaded, Figure 5 is a cross-sectional view showing the heat pipe after being leaded, and Figure 6 is the state in which the end is processed. FIG. 7 is a cross-sectional view of a leaded heat pipe that has undergone terminal processing. 1... Inner tube, 4... Working fluid, 5... Heat pipe, 8... Leaded machine, 9... Lead outer tube, 11... Leaded heat pipe, 12... Concave circular die.

Claims (1)

[Claims] 1 Pass a heat pipe which becomes an inner pipe through a lead-covered machine that combines a nipple and a die, cover this outer pipe with semi-molten lead or lead alloy so that both ends protrude from the heat pipe, and then solidify it. A leaded heat pipe characterized in that a concave circular die is pressed against both ends of the protruding lead outer tube of the formed leaded heat pipe to perform drawing processing, and then a small hole in the drawn center is sealed. terminal processing method.