Lid body and exhaust port closing device

Abstract

To provide a lid body capable of reducing a welding amount during manufacturing and reducing a manufacturing cost, and an exhaust port closing device.SOLUTION: A lid body used to close an exhaust port in a treatment tank, has a spiral pipe conduit in which a fluid pipe having a membrane structure through which fluid flows is formed in a spiral shape. The spiral pipe conduit also has a water supply pipe part through which the fluid flows toward the center of the spiral pipe conduit, and a drain pipe part through which the fluid flows away from the center of the spiral pipe conduit. The water supply pipe part and the drain pipe part are alternately provided from the center of the spiral pipe conduit toward an outer edge.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a lid and an exhaust port closing device used for closing an exhaust port in a treatment tank.

Background Art

[0002] In the refining process of molten steel, a RH type or DH type vacuum degassing device (hereinafter also referred to as "treatment tank") is used to adjust the components of molten steel by treatments such as deoxidation. In the refining process of molten steel in the treatment tank, the treatment is performed by connecting an exhaust port provided in the treatment tank to an external exhaust device. Further, during the maintenance of the treatment tank, the connection between the exhaust port and the external exhaust device is released, and in order to prevent radiant heat, high-temperature gas, etc. from flowing out from the inside of the treatment tank, the exhaust port is closed using a lid.

[0003] As the lid for closing the exhaust port, a plate-shaped member is used. Further, the lid is required to have heat resistance against heat loads received from radiant heat, high-temperature gas, etc., and conventionally, examinations such as the application of a refractory lining and an internal cooling structure enabling the flow of cooling water have been made. For example, Patent Document 1 discloses a slide valve for a high-temperature gas pipeline that employs a jacket structure through which a cooling fluid can flow as a lid having heat resistance.

[0004] Further, the lid employs a membrane structure having a pipe for flowing a cooling fluid and a fin member for connecting a plurality of pipes. In this case, the pipes are composed of straight pipes and elbow pipes (bent pipes). Then, the cooling fluid is introduced from one outer edge portion of the lid, flows through all the straight pipes and elbow pipes, and is then led out from the other outer edge portion of the lid.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, for the lid with a refractory lining to ensure heat resistance, as the usage time accumulates, the refractory falls off, and the main body (iron sheet) of the lid is exposed. Therefore, it becomes difficult to maintain heat resistance over a long period of time.

[0007] The lid described in Patent Document 1 adopts a jacket structure and thus has excellent cooling performance. However, in order to ensure the mechanical strength of the lid, it is necessary to increase the thickness of the pipeline through which the fluid flows. If the thickness of the pipeline is increased, there is a problem that the cooling performance deteriorates. Further, in a configuration adopting a jacket structure, when an external stress load acts on the lid, although it is easy to repair the damage generated on the surface of the lid, it is difficult to repair the damage generated inside due to the complexity of the jacket structure configuration. Furthermore, due to the complexity of the configuration, there is a problem in terms of manufacturing cost.

[0008] When adopting a membrane structure having a pipeline through which a fluid flows and a fin member connecting a plurality of pipelines, since a large number of straight pipes and elbow pipes are used, the amount of welding during manufacturing increases, and there is a problem in terms of manufacturing cost. Further, since a large number of elbow pipes are used, depending on the cleanliness of the flowing fluid, the pipeline may sometimes become clogged. Furthermore, the fin member connecting the plurality of pipelines forms a concave portion (depression) on the surface of the pipeline, and dust such as dust accumulates as the usage time accumulates. Then, there is a problem that uneven heat stress is generated on the surface of the lid due to the heat action of the accumulated dust. Regarding the fin slit provided in consideration of the thermal expansion difference between adjacent straight pipes arranged so that the straight pipes extend horizontally, there is also a problem that dust such as dust accumulates.

[0009] The present invention has been made in view of the above circumstances, and an object thereof is to provide a lid and an exhaust port closing device that can reduce the amount of welding during manufacturing and reduce the manufacturing cost.

Means for Solving the Problems

[0010] [1] A lid used for closing an exhaust port in a treatment tank, the lid having a spiral pipeline formed by spirally forming a fluid pipe having a membrane structure through which fluid flows. [2] The spiral pipeline has a water supply pipe portion through which the fluid flows toward the center of the spiral pipeline and a drain pipe portion through which the fluid flows away from the center of the spiral pipeline, and the water supply pipe portion and the drain pipe portion are alternately provided from the center to the outer edge of the spiral pipeline. The lid according to [1]. [3] The adjacent fluid pipes from the center to the outer edge of the spiral pipeline are joined to each other by welding. The lid according to [1] or [2]. [4] The central portion of the spiral pipeline is composed of a fluid pipe having a jacket structure. The lid according to [3]. [5] An exhaust port closing device having the lid according to [3]. [6] An exhaust port closing device provided with a flange portion and a seal portion at the outer edge of the lid according to [3].

Advantages of the Invention

[0011] According to the present invention, it is possible to reduce the amount of welding during manufacturing and reduce the manufacturing cost.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Best Mode for Carrying Out the Invention

[0013] First, the configuration of the conventional lid 10 will be described with reference to FIGS. 4 to 6. FIG. 4 shows a plan schematic view which is an example of the schematic configuration of the conventional lid 10. FIG. 5 shows a partial plan schematic view which is an example of the schematic configuration of the straight pipe 12 and the elbow pipe 13 of the conventional lid 10. FIG. 6 shows a partial cross-sectional schematic view which is an example of the schematic configuration of the straight pipe 12 and the fin portion 14 of the conventional lid 10. Note that FIG. 5 is a partially enlarged view of the schematic configuration of the straight pipe 12 and the elbow pipe 13 shown in FIG. 4. FIG. 6 is a partial cross-sectional schematic view of a plurality of straight pipes 12 with respect to the schematic configuration of the lid 10 shown in FIG. 4.

[0014] As shown in FIGS. 4 and 5, the conventional lid 10 has a straight pipe 12 and an elbow pipe 13 through which fluid can flow. The lid 10 adopts a membrane structure in which a plurality of adjacent straight pipes 12 are connected to each other with a fin portion 14 interposed therebetween. And, since a large number of straight pipes 12 and elbow pipes 13 are used, the amount of welding during manufacturing increases, which is a problem in terms of manufacturing cost. Also, since a large number of elbow pipes 13 are used, blockage of the pipeline (straight pipe 12 or elbow pipe 13) sometimes occurs depending on the cleanliness of the flowing fluid.

[0015] Furthermore, in the lid 10, the cooling fluid is introduced from one outer edge (the lower side in FIG. 4) of the lid 10, flows through all the straight pipes 12 and elbow pipes 13, and then is led out from the other outer edge (the upper side in FIG. 4) of the lid 10. Therefore, in the lid 10, a biased temperature distribution occurs, and there is a risk of causing damage such as deformation with the accumulation of the usage time. Also, as shown in FIG. 6, the fin portion 14 connecting the plurality of straight pipes 12 is a concave portion (depression) with respect to the surface of the straight pipe 12. For this reason, dust such as dust accumulates on the surface of the fin portion 14 as the usage time of the lid 10 accumulates. Therefore, there is a problem that uneven heat stress is generated on the surface of the lid 10 due to the heat action of the accumulated dust, resulting in uneven heat stress.

[0016] Next, embodiments of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 shows a schematic diagram of an example of the schematic configuration of the lid body 1 of the present invention. FIG. 1(a) shows a plan schematic diagram of an example of the schematic configuration of the lid body 1 of the present invention. FIG. 1(b) shows a side schematic diagram of an example of the schematic configuration of the lid body 1 of the present invention. FIG. 2 shows a partial cross-sectional schematic diagram of an example of the schematic configuration of the fluid pipe 2 of the lid body 1 of the present invention. FIG. 3 shows a plan schematic diagram of an example of the schematic configuration of the jacket pipe 4 at the center O of the lid body 1 of the present invention. Note that FIG. 2 is a partial cross-sectional schematic diagram of a plurality of fluid pipes 2 with respect to the schematic configuration of the lid body 1 shown in FIG. 1.

[0017] The lid body 1 according to the present invention is used for closing the exhaust port in a treatment tank such as a vacuum degassing device. As shown in FIG. 1, the lid body 1 has a spiral pipe path 3 formed by spirally forming a fluid pipe 2 having a membrane structure through which fluid flows. That is, by bending the fluid pipe 2 which is a long pipe, a spiral pipe path 3 formed in a spiral shape can be manufactured. For this reason, it is possible to reduce the amount of welding during the manufacture of the lid body 1 and reduce the manufacturing cost as compared with the conventional lid body 10. Furthermore, since a bent fluid pipe such as an elbow pipe is not required, regardless of the cleanliness of the fluid flowing through it, the deposition of scale (fluid contents) inside the fluid pipe 2 can be suppressed, and as a result, clogging of the fluid pipe 2 can be prevented.

[0018] Also, as shown in FIG. 1, the spiral pipe path 3 has a water supply pipe portion 3a in which the fluid swirls as the fluid flows through the fluid pipe 2 and heads toward the center (central portion O) of the spiral pipe path 3, and a drain pipe portion 3b in which the fluid swirls as the fluid flows through the fluid pipe 2 and moves away from the center (central portion O) of the spiral pipe path 3. Then, the water supply pipe portion 3a and the drain pipe portion 3b are alternately adjacent to each other from the center (central portion O) to the outer edge (outer edge portion S) of the spiral pipe path 3. For this reason, in all regions of the lid body 1, heat exchange always occurs between the low-temperature fluid flowing through the water supply pipe portion 3a and the high-temperature fluid flowing through the drain pipe portion 3b, and the temperature can be made uniform in the lid body 1. And by suppressing the generation of a thermal stress difference due to uneven heat, the deformation and cracking of the fluid pipe 2 can be prevented. That is, the heat resistance of the lid body 1 can be improved.

[0019] Furthermore, as shown in FIG. 2, a plurality of adjacent fluid pipes 2 are joined to each other by welding from the center to the outer edge of the spiral pipe 3. That is, compared with the fin portion 14 in the conventional configuration, the area and depth of the concave portion (depression) on the surface of the fluid pipe 2 can be reduced. For this reason, the deposition of dust on the surface of the lid 1 can be suppressed, and the generation of uneven heat caused by the thermal action of the dust can also be suppressed. In addition, since the plurality of adjacent fluid pipes 2 are the water supply pipe portion 3a and the drain pipe portion 3b in the spiral pipe 3, by joining the water supply pipe portion 3a and the drain pipe portion 3b to each other by welding, the effect of temperature uniformity in the lid 1 can be further improved.

[0020] Moreover, since a plurality of adjacent fluid pipes 2 are joined to each other, even when the thickness of the pipe member of the fluid pipe 2 is reduced, the strength of the lid 1 can be ensured. Specifically, the thickness of the pipe member of the fluid pipe 2 is preferably 4 mm or more and 5 mm or less. When the thickness of the pipe member of the fluid pipe 2 is less than 4 mm, with the increase in thermal stress due to uneven heat, the occurrence of distortion and cracks in the fluid pipe 2, and damage due to wear and corrosion will be induced. Also, when the thickness of the pipe member of the fluid pipe 2 is greater than 5 mm, the temperature difference between the inner surface and the outer surface of the fluid pipe 2 becomes large, and cracks in the fluid pipe 2 are likely to occur due to the thermal stress caused by the temperature difference, and the cooling capacity will decrease.

[0021] Next, the jacket pipe 4 at the center O of the lid body 1 will be described. As shown in FIG. 1, the center O of the spiral pipeline 3 is composed of a fluid pipe (jacket pipe 4) with a jacket structure. And, as shown in FIG. 3, the jacket pipe 4 has a partition plate 5, a guide portion 6, a water inlet 7, and a drain outlet 8. The partition plate 5 and the guide portion 6 define a flow path for the fluid flowing inside. The water inlet 7 is connected to the water supply pipe portion 3a in the spiral pipeline 3 and receives the fluid supplied from the water supply pipe portion 3a into the jacket pipe 4. The drain outlet 8 is connected to the drain pipe portion 3b in the spiral pipeline 3 and flows the fluid that has flowed through the inside of the jacket pipe 4 into the drain pipe portion 3b. That is, the fluid supplied to the lid body 1 flows through the water supply pipe portion 3a in the spiral pipeline 3, then passes through the jacket pipe 4, flows through the drain pipe portion 3b in the spiral pipeline 3, and is discharged to the outside.

[0022] The lid body 1 can be manufactured by first manufacturing the water supply pipe portion 3a and the drain pipe portion 3b in the spiral pipeline 3 by bending a long fluid pipe 2. Then, the lid body 1 can be manufactured by combining the jacket pipe 4 and the spiral pipeline 3 (the water supply pipe portion 3a and the drain pipe portion 3b). Here, the fluid pipe 2 to be bent is preferably about 5.5 m in consideration of the size (length of the pipe portion) of the water supply pipe portion 3a or the drain pipe portion 3b. The outer diameter of the fluid pipe 2 is preferably about 38.1 mm in consideration of the cooling capacity of the fluid flowing inside and the strength of the fluid pipe 2. The fluid pipe 2 is preferably an industrial steel pipe of carbon steel considering the material.

[0023] The above lid body 1 can be applied to a vacuum degassing device which is a treatment tank. Specifically, for closing the exhaust port in the vacuum degassing device, the exhaust port can be closed using the lid body 1 by the operation of the exhaust port closing device in the vacuum degassing device.

[0024] In this case, a flange portion and a seal portion may be provided on the outer edge portion S of the lid body 1. Specifically, in the direction from the central portion O of the lid body 1 toward the outer edge portion S, a flange portion extending from the outer edge portion S may be provided, and a seal portion may be provided on the surface of the flange portion. The flange portion and the seal portion may be made of a heat-resistant rubber member or a metal member (metal touch). By providing the flange portion and the seal portion on the outer edge portion S of the lid body 1, when the exhaust port is closed by the lid body 1, the exhaust port can be hermetically sealed to reliably prevent the outflow of radiant heat, high-temperature gas, etc.

Example

[0025] The results of implementing the lid body and the exhaust port closing device according to the present invention will be described. Specifically, first, a plurality of fluid pipes having an inner diameter of 38.1 mm were prepared, and the water supply pipe portion and the drain pipe portion were manufactured by bending these fluid pipes. Then, the jacket pipe, the water supply pipe portion, and the drain pipe portion were combined to manufacture the lid body. The diameter (fluid pipe panel diameter) of the manufactured lid body was 2170 mm.

[0026] Next, during the maintenance of the vacuum degassing device, the connection between the exhaust port of the vacuum degassing device and the external exhaust device was released, and the exhaust port was closed using the lid body. Then, in order to cool the lid body, a fluid having a flow rate of 80 l / min was supplied to the lid body. The pressure of the fluid flowing through the inside of the lid body was 0.3 MPa. The temperature of the fluid was 32 °C on the inlet side of the lid body and 70 °C on the outlet side, and the temperature difference between the inlet side and the outlet side of the fluid was 38 °C. At this time, the temperature inside the tank of the vacuum degassing device was about 800 °C.

[0027] As a result of the above implementation, regarding the manufacture of the lid body, compared with the manufacture of the lid body adopting the conventional structure (see FIGS. 4 to 6), a significant reduction in the amount of welding and a reduction in manufacturing costs could be achieved. Specifically, by configuring the fluid pipe 2 as a spiral pipeline 3, the use of short straight pipes and elbow pipes could be abolished. As a result, the number of butt welds of multiple fluid pipes could be reduced to about 1 / 8 of the conventional level. The manufacturing cost could be reduced to about 1 / 4 of the conventional level. In addition, since it has a spiral pipeline formed in a spiral shape, the deposition of scale inside the fluid pipe could be suppressed. Specifically, compared with the conventional membrane structure with a cleaning frequency of the fluid pipe of once every six months, the cleaning frequency could be once every three years.

[0028] Furthermore, since the water supply pipe part and the drain pipe part are alternately and adjacently provided and joined to each other by welding, the temperature uniformity in the lid body could be promoted, the generation of thermal stress difference due to uneven heat could be suppressed, and the deformation and cracking of the fluid pipe could be prevented. For this reason, compared with the conventional membrane structure with a replacement cycle of the lid body of once every five years, the replacement cycle could be once every ten years.

Explanation of Signs

[0029] 1 Lid body 2 Fluid pipe 3 Spiral pipeline 3a Water supply pipe part 3b Drain pipe part 4 Jacket pipe 5 Partition plate 6 Guide part 7 Water inlet 8 Drain outlet O Central part S Outer edge part

Claims

1. A lid used for closing an exhaust port in a treatment tank, the lid having a spiral pipeline formed by spirally forming a fluid pipe with a membrane structure through which fluid flows.

2. The spiral pipeline has a water supply pipe portion through which the fluid flows toward the center of the spiral pipeline and a drain pipe portion through which the fluid moves away from the center of the spiral pipeline, and the water supply pipe portion and the drain pipe portion are alternately provided from the center to the outer edge of the spiral pipeline. The lid according to Claim 1.

3. The adjacent fluid pipes from the center to the outer edge of the spiral pipeline are joined to each other by welding. The lid according to Claim 1 or 2.

4. The central portion of the spiral pipeline is composed of a fluid pipe with a jacket structure. The lid according to Claim 3.

5. An exhaust port closing device having the lid according to Claim 3.

6. An exhaust port closing device provided with a flange portion and a seal portion at the outer edge of the lid according to Claim 3.

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