JPH11166397A - Covered conduit excellent in corrosion resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the corrosion resistance of a covered conduit by enclosing the inner empty part with a titanium thin plate, and filling concrete to the back surface of the titanium thin plate. SOLUTION: The whole inner empty part 4 of a covered conduit is enclosed by a cylindrical titanium thin plate 1 having a circular section and formed of mutually connected corrugated plates, and concrete 2 is poured to the back surface of the titanium thin plate 1. Since a cylindrical structure formed of the corrugated titanium thin plate 1 has shape holding performance by itself, the concrete 2 can be poured to the outside without constructing a form for holding the shape, and the construction cost can be minimized. After the concrete 2 is solidified, the concrete 2 protects the titanium thin plate 1 from an external impact, and the titanium thin plate 1 has the function of protecting the concrete from corrosion. When a fluid carried in the conduit has a high temperature, for example, a cooling piping 3 is set on the outside of the titanium thin plate 1 to cool the conduit, whereby the titanium thin plate 1 and the concrete 2 can be cooled to improve the durability of the covered conduit. Since the corrosion resistance of the covered conduit is high even under corrosive environment, this conduit is extremely useful.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a culvert having excellent corrosion resistance in a corrosive environment.

[0002]

2. Description of the Related Art In a flue for guiding exhaust gas of a high-temperature heating furnace from a heating furnace to a chimney, a pipe for seawater or an acidic aqueous solution, or a common groove for laying an electric wiring, etc. It may be a tunnel-shaped culvert installed inside or under the structure. These culverts
If it is necessary to withstand long-term use, and if the constituent materials deteriorate, it is difficult or expensive to repair the pipe compared to pipes exposed outside the building. If the surrounding environment is slightly corrosive, it is necessary to consider the corrosion resistance of the material constituting the culvert.

[0003] When a flue of exhaust gas from a high-temperature heating furnace, for example, a heating furnace of a continuous hot rolling apparatus for steel is installed underground, the flue is conventionally made into a box-shaped or rectangular reinforced concrete structure.
A structure in which refractory bricks were arranged on the inner surface was adopted.
However, the exhaust gas is hot and some SO _x , N
O _x system and contain corrosive components such as a gas, and since the joints of the refractory bricks of the inner surface of the flue does not have air-tightness, when passed a long period is reinforced concrete that constitutes the flue deteriorated There is a problem that a crack occurs in the reinforced concrete portion and the reinforced concrete portion peels off. In addition, since bending cracks and the like that occur in reinforced concrete are inevitable, in the case of a flue installed underground, groundwater infiltrates cracks, especially when the chlorine concentration of groundwater in landfills at seaside is 100 ppm.
In the above-mentioned areas, the corrosion of reinforcing bars progresses violently due to the synergistic action with the action of the exhaust gas. Corrosion of the reinforcing steel lowers the tensile strength of the ceiling of the culvert and may cause the ceiling to fall. If the cracks intensely progress on the concrete surface in contact with the inner space of the culvert, the surface will peel off. In a culvert, it is difficult to confirm the progress of such deterioration, and even if repair is performed, bricks must be demolished, so that the construction period is long and the cost required for repair is high.

In addition, when the temperature of the fluid passing through the culvert is high, there has been a demand for a means for cooling the culvert and which is not corroded by the environment.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the structure does not corrode for a long period of time even when the fluid flowing through the underdrain has corrosiveness or when the surrounding area is soil that induces corrosion.
It is another object of the present invention to provide an underdrain which is inexpensive to manufacture and has excellent corrosion resistance.

Another object of the present invention is to provide a cooling means for cooling the underdrain, which is not corroded by the environment.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the gist thereof is as follows.

A first aspect of the present invention is a culvert having excellent corrosion resistance, comprising a titanium thin plate surrounding an inner space of the culvert and concrete filled on the back surface of the titanium thin plate. More preferably, the titanium thin plate has an arc-shaped cross section at least at the ceiling of the culvert. Titanium has extremely good corrosion resistance, so by arranging the titanium sheet so as to surround the inner space of the culvert, the influence of the corrosive environment of the culvert does not reach the concrete part on the back of the titanium sheet. Since the thin plate can maintain its soundness without being corroded for a long period of time, the concrete portion is not deteriorated by the corrosive environment and cracks do not progress. In addition, by making the cross section of the ceiling of the culvert arc-shaped, the shape of the culvert can be maintained only by the compressive strength of concrete, so the concrete part can be made of plain concrete, Be released. The arc shape is a shape that includes an arc shape and a part of an ellipse, and is a shape that allows an arch to be formed and the shape to be maintained only by compressive force. Since the back surface of the titanium thin plate is filled with concrete, even if the titanium thin plate is thin, it is not damaged or deformed even by an impact such as a collision of a foreign substance.

A second aspect of the present invention is the underdrain excellent in corrosion resistance according to the first aspect, wherein the titanium thin plate has a corrugated shape. The rigidity of the thin plate can be increased by forming the titanium plate into a corrugated shape instead of a flat plate, and when filling the concrete on the back of the titanium thin plate after disposing the titanium thin plate, the formwork is also performed while the concrete is uncured. It is possible to maintain the shape of the titanium thin plate without using.
Further, the use of a corrugated shape makes it possible to use a thinner titanium plate.

A third aspect of the present invention is the first aspect of the present invention, wherein the titanium thin plate is formed by winding a titanium thin strip in a spiral shape, and joining portions of adjacent strips are joined by goby folding. Or a second culvert excellent in corrosion resistance. Thereby, since the titanium thin plate is formed in a pipe shape in advance, the construction at the site is easy, and since the joint between the strips is not a welded structure, the processing cost can be reduced.

A fourth aspect of the present invention is the underdrain excellent in corrosion resistance according to the first to third aspects of the present invention, wherein cooling pipes are arranged on the back surface or the inner surface of the titanium plate. As a material of the cooling pipe, titanium is preferable. Further, it is more preferable that the cooling pipe is formed by winding a titanium sheet strip in a spiral shape, and joining portions of adjacent strips are joined by goby folding. Thereby, even if the fluid flowing through the underdrain is at a high temperature, it is possible to cool the titanium plate constituting the underdrain and the concrete on the back surface thereof. By using titanium for the material of the cooling pipe, the corrosion resistance of the cooling pipe can be improved.

A fifth aspect of the present invention is the first aspect of the present invention, wherein a fire-resistant and heat-insulating material is provided on the inner surface of the titanium thin plate.
This is an underdrain excellent in corrosion resistance of Nos. 1 to 4. Thereby, even when the fluid flowing through the underdrain is at a high temperature, it is possible to prevent the titanium plate constituting the underdrain and the concrete on the back surface thereof from being directly exposed to the high temperature.

In the present invention, the "underdrain" is a tunnel-shaped passage installed inside a structure or underground, and the passage through which a fluid such as gas or liquid flows, and electric wiring This is a concept that includes grooves for laying and the like.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a sectional shape of a culvert, a circular shape, an arch type, a ceiling trapezoidal type and the like as shown in FIG. 3 can be selected. The titanium sheet surrounding the inside of the culvert is
It is arranged according to the cross-sectional shape of the inside of the culvert, and its back is filled with concrete. When the temperature of the fluid passing through the culvert is high, a fire-resistant and heat-insulating material is disposed on the inner surface of the titanium sheet.

When the cross-sectional shape is formed by a combination of flat surfaces such as a trapezoidal ceiling, the titanium thin plate used is also a flat plate. Adopt a method of attaching a titanium sheet to the concrete surface after constructing the reinforced concrete part on the back, or a method of placing the titanium sheet on a concrete form before pouring concrete, and simultaneously casting concrete and attaching the titanium sheet. be able to. After the concrete is solidified, the concrete has a function of protecting the titanium sheet from damage such as impact, and the titanium sheet has a function of protecting the concrete from corrosion.

When the cross-sectional shape is circular or the ceiling has an arc shape such as an arch shape, the durability of the culvert can be further improved. As for the concrete part, it is possible to maintain a strong structure based on the shape retention ability of the arch. Since the shape of the culvert can be maintained only by the compressive strength of the concrete, the concrete can be made straight and the problem of corrosion of the reinforcing steel is released. Also, when the surface of the ceiling has a flat surface, it is necessary to attach the titanium plate to the concrete part so as not to peel off from the concrete part, but if the cross section is circular or the ceiling is arched,
Due to the shape retention capability of the arch, the titanium sheet does not fall by itself.

When the ceiling has an arch shape, the cross-sectional area of the culvert is small when the cross-sectional shape of the culvert is semicircular, and when the culvert has a flat portion on the side surface, the titanium thin plate is formed even if it is not as large as the flat portion of the ceiling. There is a possibility of peeling and concrete peeling. On the other hand, if the cross section is circular, there is an advantage that the cross sectional area is large, and there is no possibility that the titanium thin plate or concrete is peeled off at any part of the cross section.

The titanium sheet surrounding the inner space of the culvert is
It is preferable to surround the entire inner space portion. However, in the case where the bottom of the fluid passage has little influence on the rigidity of the entire culvert even if the concrete is deteriorated, it is possible to dispose the titanium thin plate only at this portion.

If a corrugated corrugated plate as shown in FIG. 2 is adopted as the titanium thin plate, and the corrugated plates are connected to each other to form a titanium thin plate cylinder, a cylindrical structure formed of the titanium thin plate can be obtained. However, the construction cost itself can be reduced by adopting a construction method in which concrete is poured into the outside without constructing a form for maintaining the shape. Further, the corrugated plate makes it possible to further reduce the thickness of the titanium thin plate necessary for maintaining the minimum shape. Since the material cost of titanium is higher than that of ordinary steel or stainless steel, reducing the thickness is extremely effective in reducing the manufacturing cost. The shape of the waveform is shown in FIG.
In addition to the triangular waveform shown in the above, a sine shape, a circular sine shape, and the like can be selected.

As the titanium material of the titanium thin plate used in the present invention, either pure titanium or a titanium alloy can be used. The titanium sheet is usually installed in a culvert by connecting a number of cut plates. If welding is to be used for joining titanium, TIG welding is required and it is expensive, so a joining method using bolts, nuts, rivets and the like is adopted. FIG. 2 shows an example of the joining of titanium thin plates when the cross section is arc-shaped and a corrugated plate is employed. Titanium cutting plates 5a, 5b, 5c,
A bolt nut 6 is employed for joining between 5d.

Since the titanium thin plates are joined to each other by employing bolts and nuts or rivets, the titanium thin plate structure itself is not an airtight structure. However, if it is a normal culvert, even if the airtightness of the joint is not completely maintained, by covering the whole with a thin titanium plate and filling the back with concrete, it is sufficient from the viewpoint of preventing concrete deterioration. It is possible to have a protection function.

When the diameter of the culvert is small, as shown in FIG. 4, it is possible to use a spiral tube in which a titanium sheet strip is previously wound in a spiral shape and joined. If a welding method is used to join the adjacent strips, the cost is increased. Therefore, a goby fold method as shown in FIG. As shown in FIG. 4 (b), when the strip of titanium sheet is a corrugated sheet and the direction of the back of the wave and the longitudinal direction of the strip are matched, the rigidity of the spiral tube can be improved and the titanium sheet can be improved. Can be made thinner.

When the fluid flowing through the culvert is hot, FIG.
By installing a cooling pipe 3 outside the titanium thin plate 1 to cool the culvert as shown in FIG. 1, it becomes possible to cool the titanium thin plate 1 and the concrete 2 behind it, thereby improving the durability of the culvert. Is effective in The cooling pipe may be installed inside the titanium thin plate 1. When the cooling pipe 3 is disposed outside the titanium thin plate 1 surrounding the culvert, it is not always necessary to use the highest corrosion resistant material. But usually
Since the underdrain is installed in a place where repair is difficult, if titanium is also used for the material of the cooling pipe, it is possible to make the underdrain unnecessary to repair for an extremely long time. Furthermore, since the cooling pipe can be a small-diameter pipe, it is possible to use a spiral pipe in which the above-mentioned titanium thin strip material is wound in advance in a spiral shape and joined. It is preferable to use the goby fold method for joining adjacent strips.

When the temperature of the fluid flowing through the underdrain is high, the temperature of the concrete and titanium sheet constituting the underdrain can be prevented by disposing a refractory and heat-insulating material inside the titanium sheet. The cooling effect is further increased if the above-mentioned cooling pipe is provided in parallel. As the heat insulating material, block-shaped brick, rock wool, ceramic fiber, or the like can be used. When a block-shaped brick is used, it is necessary to build the brick as a vaulted ceiling of the culvert. If the shape of the titanium thin plate portion is circular or arched as shown in FIG. 5, the brick 10 may be built along the surface shape of the titanium thin plate, so that brick construction is extremely easy. Having.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention was carried out in the case of constructing an underground flue for guiding exhaust gas from a heating furnace of a continuous hot rolling apparatus for steel from the heating furnace to a chimney. FIG. 1 shows the cross-sectional shape. That is,
The titanium thin plate 1 was arranged in a circular cross section, and the back of the titanium thin plate 1 was filled with unreinforced concrete 2.

The diameter of the titanium thin plate portion of the flue is 3 m, the thickness of the titanium thin plate used is 2.7 mm, and the pitch is 150 mm.
mm and a height of 50 mm. 1.2m × 2.5
The titanium thin plate having a size of m was processed into an arc shape having a diameter of a flue, and the plates were joined together on site with bolts and nuts to form a pipe as shown in FIG.

Outside the titanium thin plate 1, a titanium pipe 3 for flowing cooling water for cooling is provided. A spiral tube of a titanium strip having a diameter of 200 mm and a plate thickness of 0.4 mm was used. The joint of the band is goby-folded.

First, a titanium stud was installed on the inner surface of the titanium thin plate of the flue, and further, a row of fire-resistant and heat-insulating materials 10 were arranged inside the titanium stud as shown in FIG. Since the cross section of the titanium thin plate portion has a circular shape, the refractory heat insulating material could be very easily constructed by using the shape.

As a result of constructing the flue by adopting the above structure, the cost required for the construction can be reduced.
Furthermore, since the inside of the flue is surrounded by the titanium sheet, the concrete is shielded from the corrosive atmosphere, so that the concrete does not deteriorate and peel off, the titanium sheet itself does not corrode, and its soundness is maintained. As a result, the problem of corrosion of reinforcing bars has been eliminated, and the life of the flue after construction can be maintained semi-permanently.

[0030]

According to the present invention, it is possible to obtain an underdrain excellent in corrosion resistance and extremely low in the production cost even in a corrosive environment. In addition, the culvert was effectively cooled, and the durability was further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a culvert according to the present invention.

FIG. 2 is a perspective view showing a situation in which a titanium sheet having a waveform according to the present invention is joined by bolts and nuts.

3A and 3B are cross-sectional views showing the shape of the inner space of a culvert according to the present invention, wherein FIG. 3A shows a case where the cross section is circular, FIG. 3B shows a case where the cross section is arched, and FIG. Indicates a trapezoidal shape.

FIG. 4 is a plan view (partial cross section) showing a pipe obtained by spirally winding a titanium thin strip material of the present invention, and (a).
Is a plan view using a titanium thin plate having no waveform,
(B) is a plan view in the case of using a corrugated titanium thin plate, and (c) is an enlarged cross-sectional view showing a goby fold.

FIG. 5 is a sectional view of a culvert in which the refractory brick of the present invention is installed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Titanium thin plate 2 Concrete 3 Cooling pipe 4 Inner space 5 Titanium thin plate with corrugation 6 Fastening bolt and nut 7 Spiral pipe 8 Spiral pipe 9 Goby fold joint 10 Fireproof and heat insulating material

Continuing from the front page (72) Inventor Hayato Takemura 1 Sakai City Chikko Yawatacho Inside Nippon Steel Corporation Sakai Works (72) Inventor Yasuo Takahashi 2-6-3 Otemachi, Chiyoda-ku, Tokyo New Japan Inside Steel Works

Claims (8)

[Claims] 1. A culvert having excellent corrosion resistance, comprising: a titanium thin plate surrounding an inner space portion of the culvert and concrete filled on a back surface of the titanium thin plate. 2. The underdrain having excellent corrosion resistance according to claim 1, wherein the titanium thin plate has an arc-shaped cross section at least in a ceiling portion of the underdrain. 3. The underdrain excellent in corrosion resistance according to claim 1, wherein the titanium thin plate has a corrugated shape. 4. The corrosion resistance according to claim 1, wherein the titanium sheet is formed by winding a titanium sheet strip in a spiral shape, and joining portions of adjacent strips are joined by goby folding. Excellent culvert. 5. The underdrain excellent in corrosion resistance according to claim 1, wherein a cooling pipe is arranged on a back surface or an inner surface of the titanium thin plate. 6. The underdrain excellent in corrosion resistance according to claim 5, wherein the material of the cooling pipe is titanium. 7. The corrosion resistance according to claim 6, wherein the cooling pipe is formed by spirally winding a titanium thin strip material, and joining portions of adjacent strip materials are joined by goby folding. Excellent culvert. 8. The underdrain excellent in corrosion resistance according to claim 1, wherein a fire-resistant and heat-insulating material is disposed on the inner surface of the titanium thin plate.