JPH0236878B2 - - Google Patents

Abstract

PURPOSE:To prevent the accident of breakage by a method wherein the title device is constituted by combining a sealing member provided with a thin part, which moves by the internal pressure of a heat pipe, at the end of the heat pipe, and a rapture assisting member provided with a pointed edge, opposed to the outer surface of the thin part and fixed at the end of the heat pipe. CONSTITUTION:A sealing member 14, which seals the end of a heat pipe 5, is provided with a thin part 14a, movable and rapturable by the internal pressure of the heat pipe 5, while the end of the heat pipe 5 and the sealing member 14 are connected by welding 15. A rapture assisting member 16, provided at the back surface of the thin part 14a, is connected to the sealing member 14 by welding 17. Further, a knife 16a, fixed to the end of the heat pipe 5 and capable of rapturing the thin part 14a, and a communicating hole 16b, which releases the internal pressure of the heat pipe 5, are provided in the title device. When the internal pressure rises abnormally, the thin part 14a is raptured by the internal pressure through the knife 16a, whereby the internal pressure may be released to atmosphere through the communicating hole 16b. Accordingly, the accident of breakage of the heat pipe itself may be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a heat pipe used in a waste heat recovery device that recovers sensible heat from a high-temperature slab, and particularly to a protection device for preventing damage to the heat pipe. It is.

[Conventional technology]

For example, in a steel mill, when a rectangular ingot (hereinafter referred to as a slab) is melted and rolled, it generates waste heat of over 1000℃, or it is heated in a blast furnace in the slag from various smelting furnaces. Mine slag (hereinafter referred to as slag) is huge both in quantity and heat, so from the standpoint of energy conservation, each steelworks has installed waste heat boilers and heat pipes to effectively utilize this waste heat. A type of waste heat recovery device is installed.

Conventionally, this type of waste heat recovery apparatus 1, as shown in FIGS. 1 and 2, uses a conveying device 2 composed of rollers, walking beams, etc. to collect slabs,
Since the heat source 3 such as slag generates radiant heat 4 while being transported, the heat absorbing part 5a of the heat pipe 5 is arranged close to the moving heat source 3 as shown in FIG. It was arranged in a drum 7 having a liquid 6 to be heated.

Therefore, the sensible heat possessed by the heat source 3 is transferred as radiant heat 4 to the heat absorption part 5a of the heat pipe 5 or the fin 8.
The heat is recovered in the heat absorbing part 5a of the heat pipe 5 through
is carried out by repeating evaporation and condensation.

In the drum 7, a heat pipe 5
The heated liquid 6 that has received heat from the heat radiation section 5b is heated and becomes generated steam 10 in the drum 7, and the heat is recovered as steam 12 from the steam pipe 11, and the waste heat is effectively used.

[Problems to be Solved by the Invention] However, when the supply of the heated liquid 6 into the drum 7 in the waste heat recovery device 1 stops, or when the surface 13 of the heated liquid 6 suddenly decreases, The problem is that the heat dissipation section 5b of the heat pipe 5 is not cooled, and on the other hand, the heat medium 9 continues to evaporate in the heat absorption section 5a, causing an abnormal increase in internal pressure, which may eventually lead to the failure of the heat pipe 5. be.

Therefore, it is conceivable to provide a bypass in the conveyance system for slabs, slag, etc., and use the bypass to stop the heat supply to the heat pipe 5 in the above-mentioned case. Therefore, it is difficult to provide a bypass in the conveyance system for slabs, etc. Further, it is not preferable to restrict the flow of these heat sources 3 because it affects the operation rate of the entire plant.

In order to prevent damage to the heat pipe, for example, as described in Japanese Utility Model Application No. 52-113467, a pressure plug made of a thin metal plate is provided at the end of the heat pipe to prevent the internal pressure of the heat pipe from becoming too high. A structure has been proposed in which the pressure plug is ruptured by the pressure caused by the pressure.

However, in order to break a thin metal plate using only the constant internal pressure of the heat pipe, it is necessary to control the material and thickness of the thin metal plate, as well as the tensile strength when the thin metal plate is attached, etc., very strictly. This results in higher costs and lower productivity. Furthermore, if the metal plate becomes even slightly thick, the metal plate will not break due to internal pressure alone, and even if a pressure plug is provided, there is a risk that the heat pipe may explode.

Furthermore, a structure for preventing damage to a heat pipe has been proposed as described in Japanese Patent Application Laid-Open No. 53-80047. This damage prevention structure is fixed by pressing a thin film in a stretched state to a stepped portion provided near the end of the heat pipe using packing and a holding ring. On the other hand, by providing a through hole in the side wall of the heat pipe,
One opening of a conduction pipe bent into a substantially C-shape is fixed so as to communicate with the through hole, and a bellows is attached to the other opening, and a needle body is fixed to the lower surface of the bellows. It is arranged so as to face the stretched thin film.

When the internal pressure of the heat pipe increases, the internal pressure acts on the bellows through the through hole and the conduction pipe, and the bellows stretches, moving the needle and breaking the thin film, releasing the gas inside the heat pipe to the atmosphere. The system is set up to do so.

However, this structure uses bellows, which are exposed to the outside, so such heat pipes cannot be used, for example, in waste heat recovery equipment at steel plants, which operate at high temperatures and are relatively dusty. If used under these conditions for a long period of time, the bellows may deteriorate or
Dust adheres to and accumulates on the bellows' bellows, which may deteriorate its pressure response and prevent it from operating properly.

In addition, since the thin film is always under tension and comes into contact with the vapor of the high-temperature heat medium, if it is used for a long period of time, its mechanical strength may decrease or change in quality. If the heat pipe rises, cracks or pinholes may occur in the thin film, causing heat transfer to be released into the atmosphere and wasting the heat pipe.

Furthermore, if the entire bellows stretches evenly,
The needle can be inserted perpendicularly to the membrane and break the membrane, but if the bellows tends to stretch even slightly, the needle will become oblique to the membrane.
When the tip of the needle comes into contact with the membrane, it collapses as the needle is inserted. Therefore, the thin film cannot be broken, and the heat pipe may be damaged even though a heat pipe is equipped with a protective device to prevent damage.

The present invention attempts to overcome these conventional drawbacks, and its purpose is to prevent heat pipes from being damaged.

[Means for solving problems]

In short, in order to achieve this object, the present invention includes a sealing member having a thin wall portion that expands due to the internal pressure of the heat pipe, and a bursting auxiliary member having a pointed end facing the outer surface of the thin wall portion. fixed to the end of the heat pipe, the thin wall portion expands toward the pointed end due to an increase in the internal pressure of the heat pipe, and the expanded thin wall portion ruptures at the fixed end of the heat pipe; Further, the rupture assisting member is provided with a communication hole through which the internal pressure inside the heat pipe is released to the outside of the heat pipe system when the heat pipe ruptures.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 3, which is an enlarged cross-sectional view of the end of the heat pipe 5. As shown in FIG.

In the figure, reference numeral 14 denotes a sealing member that seals the end of the heat pipe 5. The sealing member 14 is provided with a thin wall portion 14a that moves and ruptures due to the internal pressure of the heat pipe 5. The part and the sealing member 14 are joined by welding 15.

Reference numeral 16 denotes a rupture auxiliary member provided on the back surface of the thin wall portion 14a. In addition, a knife 16a for damaging the thin wall portion 14a and a communication hole 16b for releasing the internal pressure inside the heat pipe 5 are provided.

In such a structure, if the internal pressure of the heat pipe 5 rises abnormally, the thin wall portion 14 will be damaged by the internal pressure.
a bulges from the position shown by the solid line in FIG.
This allows the internal pressure of the heat pipe 5 to escape to the atmosphere through the communication hole 16b.

Hereinafter, calculated values and actual measured values of the bursting pressure P of the thin wall portion 14a and the plate thickness h of the thin wall portion 14a, which were performed by the inventor, will be explained using FIG. 4.

Bursting pressure P can be determined by the following formula.

P≒k×64×E× ^h3 ×w/12×(1− ^r2 )× ^a4 ×
100 However, P: Burst pressure (Kg/cm ² G) k: Coefficient E: Longitudinal elastic modulus of thin wall portion 14a (Kg/mm ² ) h: Thickness of thin wall portion 14a (mm) w: Center of thin wall portion 14a Deflection amount (mm) r: Poisson's ratio of thin wall portion 14a a: Radius of thin wall portion 14a (mm) At this time, SUS304 is used as the material of thin wall portion 14a, E = 2.0×10 ⁴ (Kg/mm ² ), r=0.3, w=2.5
(mm), and a=9 (mm). In Fig. 4, the ○ mark indicates the calculated value, the △ mark indicates the confirmation test result, and the thin part 14a
Experiments were conducted with the plate thickness h of 0.2 mm, 0.3 mm, 0.35 mm, and 0.4 mm, respectively, and as shown in Figure 4, it was confirmed that the heat pipe ruptured around the calculated value.
It was also demonstrated that it is effective as an end plate.

As described above, due to the rupture of the thin wall portion 14a, the internal pressure inside the heat pipe 5 is reduced between the thin wall portion 14a and the communication hole 16b.
This allows the heat pipe 5 itself to be prevented from bursting.

Furthermore, in the embodiment of the present invention, even if the internal pressure of the heat pipe 5 increases abnormally, only the thin wall portion 14a will rupture, and the heat pipe 5 itself can be prevented from rupturing. Therefore, the sealing member 14 is replaced with a new one. This makes it possible to reuse the heat pipe 5, eliminate the trouble of replacing it with a new heat pipe 5, and enable quick repair.

As described above, in the embodiment of the present invention, the thin wall portion 14a that moves due to the internal pressure of the heat pipe 5,
Knife 16a fixed to the end of the heat pipe 5
Since the protective device is constructed by
The distance between the heat pipe 5 and the knife 16a can be adjusted accurately, and damage to the protection device can be adjusted as desired according to the rising pressure of the heat pipe 5.

The one in FIG. 5 is shown in another embodiment, and the difference from the one in FIG. 3 is that in the one in FIG.
In the case shown in FIG. 5, the sealing member 14 is fastened to the end of the heat pipe 5 with a mounting nut 18.

As a result, by removing and tightening the mounting nut 18, the new thin-walled portion 14a can be easily installed.
It can be replaced with .

〔Effect of the invention〕

The present invention has the above-mentioned configuration, and even if the internal pressure of the heat pipe increases abnormally, it can be released to the atmosphere, so damage to the heat pipe itself can be prevented, and existing Even if it is, it can be easily modified by simple modification work.

Furthermore, a rupture auxiliary member is provided that has a pointed end facing the outer surface of the thin-walled portion, and the thin-walled portion can be easily ruptured as the internal pressure increases. Compared to conventional products, there is no need to strictly control the material and thickness of thin-walled parts, which reduces costs and improves productivity. Furthermore, since a bursting auxiliary member is provided to easily tear the thin walled part, the operation reliability as a safety device is high, and even though the heat pipe is equipped with a safety device like the one proposed previously, the heat pipe will explode. You don't have to worry about it happening.

Furthermore, since the thin-walled portion of the present invention is held to such an extent that it moves and expands due to the increase in internal pressure of the heat pipe, the thin-walled portion is not always fixed in a tensioned state as in conventional proposals. There is little deterioration in mechanical strength, etc., even when exposed to heat medium vapor. Further, since no bellows or the like is used, and the internal pressure of the heat pipe directly expands and ruptures the thin-walled portion, the pressure response is good. Furthermore, since the rupture assisting member is fixed to the end of the heat pipe, the tip thereof does not wobble, and the thin wall portion can be reliably ruptured.

[Brief explanation of drawings]

Figures 1 and 2 show a waste heat recovery device, with Figure 1 being a plan view, Figure 2 being a cross-sectional view taken along the line - - of Figure 1, and Figure 3 showing the end of the heat pipe of the present invention. FIG. 4 is an enlarged view of the attached protection device, FIG. 4 is a characteristic curve diagram showing the relationship between bursting pressure and plate thickness, and FIG. 5 is an enlarged view of another embodiment of FIG. 3. 5...Heat pipe, 14...Sealing member, 14
a... Thin wall portion, 16... Supporting member, 16a... Knife, 16b... Communication hole.

Claims (1)

[Claims] 1. A sealing member having a thin-walled portion that expands due to the internal pressure of the heat pipe, and a bursting auxiliary member having a pointed end facing the outer surface of the thin-walled portion are both fixed to the end of the heat pipe, and the heat pipe is The structure is configured such that the thin wall portion expands toward the pointed end due to an increase in internal pressure, and the expanded thin wall portion ruptures at the fixed pointed end, and when the bursting occurs, the internal pressure within the heat pipe is heated. A heat pipe characterized in that the bursting auxiliary member is provided with a communication hole through which the heat escapes to the outside of the pipe system.