JPH0432695A - Sealing up of heat pipe - Google Patents

Abstract

PURPOSE:To achieve a better sealability without disturbing the pressure seal interface by performing a sealing work after substantially smoothing the irregularities caused by the groove in the internal circumferential wall at an open end of a metal pipe. CONSTITUTION:A mandrel 2 made of a material higher in hardness than a heat pipe 1 is inserted into a hollow member at an open end 12 of the head pipe 1. Then, for example, an open end member 12 undergoes a swaging being reduced in diameter with the application of a mechanical pressure from the outer circumference by a rotary swaging machine or the like. In this swaging work, a groove 11 carved in a circumferential wall 10 of the open end 12 is squeezed with the existence of the mandrel 2 so that the inner circumferential surface 10 of the open end 12 is made almost smooth. After the end of the swaging work, the mandrel 2 is pulled out and after the inside of the heat pipe 1 is cleaned up by a detergent to be evacuated, a working liquid such as pure water is injected thereinto. The open end 12 finer in diameter is cold pressure welded using a pressure welding machine 3 and the pipe is cut at a pressure welded part 13 on the final end side of the heat pipe 1. Using a welder 4, a weld part 40 is formed on a cut end face 14 to seal up the heat pipe 1 completely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of sealing a beat pipe having a groove-shaped wick after injecting a working fluid into the beat pipe.

[Prior art] The inner circumferential wall of a metal pipe such as copper or aluminum used as a heat vibrator usually has thin grooves in order to improve the reflux efficiency of working fluid such as pure water and reduce the thermal resistance of the heat vibrator. installed in the longitudinal direction. That is, as shown in FIG. 1, the inner circumferential wall 10 of the cross section of the metal pipe has a gear-like shape due to the presence of the groove 11.

Generally, when manufacturing a heat vibrator, the opening of a grooved metal pipe that is open at one end and sealed at the other end is swaged (formed by applying mechanical pressure to the pipe from the outside). After reducing the diameter by vacuuming, injecting working fluid, and temporarily sealing the narrow diameter part by cold pressure welding, the pipe is crushed into a flat shape), and then welded by TIG etc. to seal the metal vibrator. Work is being done to

[Problems to be Solved by the Invention] However, in the conventional method, it is very difficult to completely seal the metal vibrator during the above-mentioned cold pressure welding. That is, since grooves are cut into the inner circumferential wall of the metal pipe, when the pipe is crushed into a flat shape, the grooves join together, which tends to cause interface disturbance. In order to completely seal the hydraulic fluid by eliminating the interface disturbance at the joint surfaces of the grooves, it was necessary to press the grooves together until the wall thickness of the sealing part became considerably thinner. Further, in this case, since the sealing portion is thin, there is also a problem in that the mechanical strength is reduced.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide a method that can easily and completely seal a heat pipe after the working fluid is injected into the heat pipe.

[Means for Solving the Problems] The method for sealing a beat pipe of the present invention includes injecting a working fluid into a metal vibrator having an open end at one end and then hermetically sealing the open end. At this time, the sealing process is performed after smoothing the inner circumferential wall of the open end of the metal pipe.

[The reason why the opening end of the metal pipe cannot be sealed well is because the grooves are cut into the inner circumferential wall of the metal pipe as described above. If the sealing process is performed after smoothing, there will be no disturbance of the interface of the sealing part due to the joining of the grooves, and the open end of the metal pipe can be easily sealed with a good degree of sealing.

[Example] An example of the present invention will be described in detail below based on the drawings.

FIG. 1 is a sectional view of the heat vibrator 1, and its inner peripheral wall 1
0, a groove 11 for working fluid circulation is formed in the longitudinal direction. As the heat vibrator 1, a metal pipe having good thermal conductivity, such as copper or aluminum, is used.

FIGS. 2(a) to 2(e) are diagrams for explaining specific examples of the sealing method of the present invention. First, as shown in FIG. 2(a), a mandrel 2 made of a material harder than the heat vibe 1 is inserted into the hollow H of the open end 12 of the heat vibe 1. Next, as shown in FIG. 2(b), a swaging process is performed on the open end 12 to reduce its diameter by applying mechanical pressure from the outer circumference of the pipe using, for example, a rotary swaging machine. During this swaging process, the groove 11 carved in the inner peripheral wall 10 of the open end 12 is crushed by the presence of the mandrel 2, and the inner peripheral wall 10 of the open end 12 is crushed.
is assumed to be a substantially smooth surface. After the swaging process is completed, the mandrel 2 is pulled out, the inside of the heat vibrator 1 is cleaned with a cleaning liquid, and after being evacuated, a working fluid such as pure water is injected. Note that the term "smoothing" as used in the present invention does not refer only to a completely smooth surface, but may be smoothing to the extent that some unevenness is present as long as there is no problem during the press-welding process described later.

Then, as shown in FIG. 2(C), the reduced diameter opening end 12 is cold-welded using the pressure welding machine 3, and the heat vibrator 1 is temporarily sealed by forming pressure-welded parts 13 at two locations, for example. Stop. Roughly as shown in FIG. 2(d), the pipe is cut at the pressure contact portion 13 on the terminal end side of the heat vibe 1. FIG. 3 shows the cross-sectional shape of the cut end surface 14 at this time,
Since the inner circumferential wall of the open end 12 of the heat vibrator 1 does not have the groove 11 and is pressed in a substantially smooth state,
As shown in the figure, the bonding interface S due to pressure welding can be flat and have excellent sealing properties. As in the present invention,
For example, if cold pressure welding is performed without smoothing the groove 11 on the inner circumferential wall of the opening end 12 during swaging, as shown in FIG. In order to achieve the same sealing performance as in the method of the present invention, it is necessary to increase the amount of pressure welding and make it more flat, which reduces the mechanical strength of the pressure welded part. Undesirable.

Thereafter, as shown in FIG. 2(e), a welding section 40 is formed on the cut end surface 14 using a welding machine 4, and the heat vibe 1 is completely sealed.

Another method for smoothing the inner circumferential wall 10 of the open end 12 is to cut the groove 11 with a cutting tool using a lathe or the like before reducing the diameter of the open end 12 or after reducing the diameter by performing a swaging process. etc. In any case, Fig. 2(c)
Any means may be used as long as the groove 11 in the inner circumferential wall 10 of the open end 12 is removed and smoothed before the temporary sealing process of the open end 12 as shown in FIG. However, compared to the means of cutting the groove 11 with a lathe or the like, the means of inserting the mandrel 2 shown in this embodiment is different from the means of inserting the mandrel 2 shown in this embodiment, since the swaging process is originally an essential step when sealing the beat pipe 1. The method of this embodiment is preferable because it has the advantage that it is only necessary to insert the mandrel 2 and the number of steps does not increase as much as in lathe processing.

[Effects] According to the heat pipe sealing method of the present invention as explained above, the sealing process is performed after substantially smoothing the unevenness caused by the grooves on the inner circumferential wall of the opening end of the metal vibrator, so that the sealing pressure interface Good sealing performance can be achieved without causing any disturbance. In other words, the pressure welding work can be performed easily and reliably. Therefore, a high degree of vacuum can be maintained for a long period of time, and a highly reliable beat pipe can be provided.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the cross-sectional shape of a heat pipe, FIGS. 2(a) to (e) are explanatory diagrams arranged in the order of steps to explain an example of the sealing method according to the present invention, and FIG. 4 is a diagram showing an end face sealed by the method of the present invention, and FIG. 4 is a diagram showing an end face sealed by the conventional method. 1... Heat pipe, 10... Inner peripheral wall, 11...
Groove, 12... Opening end, 13... Pressure contact part, 14...
・Sealing end, 2...Mandrel Figure 2

Claims (1)

[Claims] When a working fluid is injected into a metal pipe with an open end at one end having a groove for circulating the working fluid in the inner peripheral wall and the open end is hermetically sealed, the inner peripheral wall of the open end of the metal pipe is smoothed and then the sealing process is performed. A heat pipe sealing method characterized by: