Gas injection pipe

Abstract

To provide a gas blowpipe that reduces falling off of a tip end.SOLUTION: A gas blowpipe 1 includes: a cylindrical pipe member 2 having a pipe first end 7 on the downstream side and a pipe second end 8 on the upstream side; a porous member 3 formed inside the pipe member 2; and a gas pipe 4 connected to the pipe second end 8 side of the pipe member 2 via a connecting member 24. When the gas blowpipe 1 is immersed in a molten metal 23, the gas pipe 4 is used with its surroundings protected by the protective material 21. The tube member 2 has a predetermined thickness in the axial direction at the pipe first end 7, and a protrusion 6 that protrudes inward from the pipe wall 5 is formed. At the pipe first end 7, the porous member 3 is partially exposed and partially covered with the protrusion. When the gas blowpipe is immersed in the molten metal 23 in a molten metal container 22 and gas G is introduced into the gas pipe 4, the gas G is blown into the molten metal container 22 through the porous member 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas injection pipe that is immersed in a molten metal in a molten metal container and injects gas into the molten metal. [Background technology]

[0002] Conventionally, gas injection, in which an inert gas is injected into molten metal, has been performed to remove gases such as oxygen and hydrogen that have become mixed into the molten metal. For example, a conventional gas injection device for a holding furnace described in Patent Document 1 has a gas injection pipe installed in a molten metal holding furnace, with the tip of the gas injection pipe extending to the vicinity of the bottom of the molten metal holding furnace. A porous injection tool is connected to the tip of the gas injection pipe. The inert gas flows into the holding furnace through the injection pipe and diffuses into the molten metal through the pores of the injection tool. With this configuration, the inert gas physically adsorbs to the oxygen in the molten metal, rendering the oxygen inert. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 4-200858 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional example, the blowing tool is connected only to the tip of the gas blowing pipe, so there is a risk that the blowing tool will fall off and be damaged by the gas pressure when the gas is blown in. In that case, there is a risk of bumping, where gas is forcefully blown out from the tip. Furthermore, if pressure is applied inside the holding furnace, there is a risk of the molten metal flowing back into the gas blowing pipe.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a gas injector tube that reduces the likelihood of the tip coming off. [Means for solving the problem]

[0006] A gas blowing pipe according to an aspect of the present invention is immersed in a molten metal in a molten metal vessel to blow in gas, and the gas blowing pipe comprises a cylindrical tubular member having a first tubular end on the downstream side and a second tubular end on the upstream side, a porous member formed inside the tubular member, and a gas pipe connected to the second tubular end side of the tubular member via a connecting member, and the center side of the tubular member is located inside a tubular wall portion that forms the outer periphery of the tubular member, and the center the opposite side to the first end of the tube is defined as the outside, the direction connecting the first end of the tube and the second end of the tube is defined as the axial direction, and the direction perpendicular to the axial direction is defined as the radial direction; the tube member has a predetermined thickness in the axial direction at the first end of the tube, and a protrusion is formed that protrudes inward from the tube wall portion; at the first end of the tube, the porous member is partially exposed and partially covered by the protrusion, and is immersed in the molten metal in the molten metal container; and when the gas is introduced into the gas pipe, the gas passes through the porous member and is blown into the molten metal container.

[0007] According to this, a part of the porous member is exposed at the first end of the tube, so that fine gas particles formed by the porous member are blown in. Also, a part of the porous member is covered by the protrusion at the first end of the tube, so that the porous member is less likely to fall off downstream.

[0008] Furthermore, the gas blowing pipe may have the protruding portion formed in a continuous ring shape in the circumferential direction along the pipe wall. In this case, since the protruding portion is formed in a continuous ring shape in the circumferential direction, the gas blowing pipe can reduce the possibility of the porous member falling off at the tip. Furthermore, since the porous member is exposed in a continuous state in the circumferential direction at the first end of the pipe, gas can be blown in a constant blowing manner regardless of the state in which the gas blowing pipe is placed in the vessel for the molten metal.

[0009] Furthermore, the protrusion of the gas blowing pipe may be formed continuously along at least a portion of the pipe wall in the circumferential direction, which can reduce the likelihood of the porous member falling off at the tip of the gas blowing pipe.

[0010] The gas blowing pipe may have a plurality of protruding portions formed at equal angular intervals in the circumferential direction. In this case, the gas blowing pipe can reduce the possibility of the porous member falling off at the tip. Furthermore, the end of the porous member has an equal proportion of exposed portions and covered portions in the circumferential direction at the first end of the pipe. Therefore, the gas blowing pipe can blow gas in a consistent manner regardless of the state in which it is placed in the molten metal vessel.

[0011] Furthermore, the gas blowing pipe may have a chord formed at the protruding portion in a direction perpendicular to the axial direction, in which case the porous member at the tip of the gas blowing pipe can be further reduced from falling off.

[0012] Furthermore, the gas injecting pipe may be configured so that the porous member end, which is the end of the porous member on the downstream side, is on the same plane in the axial direction as the protruding portion end, which is the end of the protruding portion on the downstream side, or protrudes downstream. In this case, the gas injected from the porous member is directly injected into the molten metal in a finer state without being obstructed.

[0013] Furthermore, the gas blowing pipe may be in a state where the porous member and the protruding portion are joined together at the first pipe end by a monolithic refractory material. In this case, the gap between the porous member and the protruding portion at the first pipe end of the gas blowing pipe is filled, and it is possible to reduce the accumulation and aggregation of gas, which causes bubbles to become larger.

[0014] Furthermore, the downstream end of the protruding portion of the gas blowing pipe may protrude further downstream than the downstream end of the porous member, which is the downstream end of the porous member. In this case, the downstream end of the porous member can be made flat, which makes it easy to process.

[0015] Furthermore, the gas blowing pipe may be in a state where the porous member and the protruding portion are joined together at the first pipe end by a monolithic refractory material. In this case, the gap between the porous member and the protruding portion at the first pipe end of the gas blowing pipe is filled, and it is possible to reduce the accumulation and aggregation of gas, which causes bubbles to become larger. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a view showing a state in which the gas-blowing tube 1 of the present invention is immersed in a molten metal vessel 22. [Figure 2] 1A and 1B show a gas injection pipe 1a according to a first embodiment of the present invention, in which (a) is a cross-sectional view taken along the axial center C of a pipe member 2a, and (b) is a view showing the state in which the pipe is installed in a molten metal 23 and gas G is injected therein. [Figure 3] 1 is a perspective view showing a gas blowing pipe 1a according to a first embodiment of the present invention. [Figure 4] FIG. 1 is a perspective view showing a pipe member 2a and a porous member 3a in a gas blowing pipe 1a according to a first embodiment of the present invention. [Figure 5] 1A and 1B show a gas blowing pipe 1b according to a second embodiment of the present invention, in which (a) is a cross-sectional view taken along the axial center C of a pipe member 2b, and (b) is a view showing the state in which the pipe is installed in a molten metal 23 and gas G is blown in. [Figure 6] FIG. 1 is a diagram showing a gas blowing pipe 1b according to a second embodiment of the present invention, and is a perspective view showing the gas blowing pipe 1b and a porous member 3b. [Figure 7] FIG. 10 is a cross-sectional view showing a gas blowing pipe 1c according to a third embodiment of the present invention, taken along the axial center C of a pipe member 2c. [Figure 8] FIG. 10 is a diagram showing a gas blowing pipe 1c according to a third embodiment of the present invention, and is a perspective view showing the gas blowing pipe 1c and a porous member 3c. [Figure 9] FIG. 10 is a diagram showing a gas blowing pipe 1d according to a fourth embodiment of the present invention, and is a perspective view showing the gas blowing pipe 1d and a porous member 3d. [Figure 10] FIG. 10 is a diagram showing a gas blowing pipe 1e according to a fifth embodiment of the present invention, and is a perspective view showing the gas blowing pipe 1e and a porous member 3e. [Figure 11] FIG. 10 is a diagram showing a gas blowing pipe 1f according to a sixth embodiment of the present invention, and is a perspective view showing the gas blowing pipe 1f and a porous member 3f. [Figure 12] FIG. 10 is a cross-sectional view showing a gas blowing pipe 1g according to a seventh embodiment of the present invention, taken along the axial center C of a pipe member 2g. [Figure 13] FIG. 10 is a perspective view showing a gas blowing pipe 1g according to a seventh embodiment of the present invention. [Figure 14] 10A and 10B show the state in which a gas blowing pipe 1g according to a seventh embodiment of the present invention is installed in a molten metal 23, in which (a) shows the state in which gas G is blown in when the protruding portion 6g is on the lower side in the vertical direction, and (b) shows the state in which gas G is blown in when the protruding portion 6g is on the upper side in the vertical direction. [Figure 15] FIG. 10 is a perspective view showing a gas blowing pipe 1h according to an eighth embodiment of the present invention. [Figure 16] FIG. 11 is a perspective view showing a gas blowing pipe 1j according to a ninth embodiment of the present invention. [Figure 17] FIG. 10 is a perspective view showing a gas blowing pipe 1k according to a tenth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] A gas injection pipe 1 embodying the present invention will be described below with reference to the drawings. The description of the preferred embodiment and the drawings are used to explain the technical features that can be adopted by the present invention. The present invention is not limited to these. The configurations shown in the drawings are merely illustrative examples and are not intended to limit the present invention.

[0018] <Configuration common to all embodiments> 1 to 3, a configuration common to each embodiment described later in a gas blowing pipe 1 according to an aspect of the present invention will be described. As shown in Fig. 1, the gas blowing pipe 1 of the present invention is immersed in a molten metal 23 in a molten metal container 22 to blow in a gas G. As shown in Fig. 2 etc., in the flow direction of the gas G, the side from which the gas G is supplied is defined as the upstream side, and the side from which the gas G is blown into the molten metal 23 is defined as the downstream side.

[0019] As shown in Figure 2 etc., the gas blowing pipe 1 comprises a cylindrical pipe member 2 having a first pipe end 7 on the downstream side and a second pipe end 8 on the upstream side, a porous member 3 formed inside the pipe member 2, and a gas pipe 4 connected to the second pipe end 8 side of the pipe member 2 via a connecting member 24. As shown in Figure 1, when the gas blowing pipe 1 is immersed in the molten metal 23, it is used with the gas pipe 4 surrounded by a protective material 21.

[0020] As shown in Figure 2 etc., the center side of the pipe member 2 is the inside and the side opposite to the center is the outside with respect to the pipe wall portion 5 that forms the outer periphery of the pipe member 2. As shown in Figure 3 etc., the direction connecting the pipe first end portion 7 and the pipe second end portion 8 is the axial direction, and the direction perpendicular to the axial direction is the radial direction.

[0021] The tube member 2 has a predetermined thickness in the axial direction at the tube first end 7, and is formed with a protruding portion 6 that protrudes inward from the tube wall portion 5. At the tube first end 7, the porous member 3 is partially exposed and partially covered by the protruding portion 6. When the tube is immersed in the molten metal 23 in the molten metal container 22 and gas G is introduced into the gas pipe 4, the gas G passes through the porous member 3 and is blown into the molten metal container 22.

[0022] The molten metal 23 is made of, for example, a non-ferrous metal such as aluminum, copper, etc. The porous member 3 includes either a shaped refractory such as ceramic fiber or shaped brick, or an unshaped refractory such as castable.

[0023] <Effects of the Configuration Common to Each Embodiment> The configuration common to the gas blowing pipe 1 described above has the following advantages. As shown in Fig. 2 etc., the pipe member 2 has a protruding portion 6 formed at the first pipe end portion 7, and a part of the porous member 3 is covered by the protruding portion 6. Therefore, the porous member 3 is less likely to fall off downstream.

[0024] In general, the hydrogen concentration in molten aluminum or copper can be reduced by injecting an inert gas, such as argon or nitrogen, into the molten metal. Furthermore, impurities such as oxides in the molten metal can be agglomerated by the gas bubbles and separated from the molten metal as slag, improving the metal's performance. Conventionally, degassing equipment has often used agitation systems, in which finely divided gas bubbles are injected from the tip of a rotating blade at high speed. However, this system is prone to equipment problems due to high speeds, and it is difficult to refine the bubbles when a large amount of gas is used.

[0025] The gas blowing pipe 1 of the present invention also solves these problems. The gas G blown from the gas blowing pipe 1 into the molten metal 23 in the molten metal vessel 22 passes through the porous member 3, which allows the bubbles to be made finer and improves degassing performance. A portion of the porous member 3 is exposed at the first pipe end 7. Therefore, the gas blowing pipe 1 can blow the gas G, which has been made finer by the porous member 3, directly from the porous member 3 into the molten metal 23. The gas G causes impurities such as oxides in the molten metal 23 to agglomerate with the bubbles of the gas G, which can be separated as slag.

[0026] <Configurations and Effects Common to the Gas Injection Pipe 1a of the First Embodiment to the Gas Injection Pipe 1f of the Sixth Embodiment> Next, a common configuration of the gas inlet pipe 1a of the first embodiment to the gas inlet pipe 1f of the sixth embodiment according to the present invention will be described with reference to Figures 2 to 11. The porous member end 11, which is the end of the downstream porous member 3, is on the same plane in the axial direction as the protruding portion end 16, which is the end of the downstream protruding portion 6, or protrudes downstream.

[0027] At the first tube end 7, the porous member 3 and the protruding portion 6 are joined by a monolithic refractory 9. As shown in the example of FIG. 2(a), at the first tube end 7, the porous member 3 and the protruding portion 6 are joined by a radial joint 17 and an axial joint 18 made of a monolithic refractory 9 such as mortar. Furthermore, a joint 20 between the inner peripheral surface of the tube wall portion 5 and the outer peripheral surface of the porous member 3 is also joined by a monolithic refractory 9 such as mortar.

[0028] <Effects of the configuration common to the gas blowing pipe 1a of the first embodiment to the gas blowing pipe 1f of the sixth embodiment> The configuration common to the gas blowing pipe 1a of the first embodiment to the gas blowing pipe 1f of the sixth embodiment described above provides the following advantages. As shown in FIG. 2(b), the gas G blown through the porous member 3 is blown directly into the molten metal 23 without being obstructed, allowing the gas G to be blown in a finer state. The gas blowing pipe 1 blows the gas G into the molten metal 23 with its tip pointing obliquely downward. Because the first pipe end 7 does not have a portion that protrudes downstream beyond the porous member 3, the gas G is blown directly from the end 11 of the porous member. Therefore, the fine gas G formed by the porous member 3 is less likely to agglomerate after blowing, and the concentration of hydrogen in the fine gas G mixed into the molten metal can be reduced.

[0029] Furthermore, in the gas blowing pipe 1, the porous member 3 and the protruding portion 6 are joined at the pipe first end 7 by a monolithic refractory material 9 such as mortar. Therefore, in the gas blowing pipe 1, the gap between the porous member 3 and the protruding portion 6 at the pipe first end 7 is filled, and it is possible to reduce the accumulation and aggregation of gas G, which causes bubbles to become larger.

[0030] <<Configuration and Effects of the Gas Injection Pipe 1 of Each Embodiment>> Next, the configuration and effects of each embodiment of the gas inlet pipe 1 according to the present invention will be described. In each embodiment, elements having similar functions are assigned similar reference numerals, and elements having similar functions but different shapes, etc. are distinguished by adding lowercase letters such as 2a.

[0031] <Configuration of the gas blowing pipe 1a of the first embodiment> The configuration of a gas blowing pipe 1a according to a first embodiment of the present invention will be described with reference to Figures 2 to 4. Explanation of the common configuration already described will be omitted. This also applies to the other embodiments described below. The protruding portion 6a of the pipe member 2a in the gas blowing pipe 1a is formed in a ring shape that is continuous in the circumferential direction along the pipe wall portion 5.

[0032] Specifically, in the example shown in FIG. 3 and other figures, the protrusion 6a is formed in a doughnut shape concentric with the center of the inner diameter of the pipe wall 5 of the pipe member 2a. The protrusion 6a may have a shape other than a concentric circle with respect to the center of the inner diameter of the pipe wall 5. For example, it may have an elliptical shape with a center different from the center of the inner diameter of the pipe wall 5. Alternatively, it may be formed in a ring shape with an inner surface having an uneven shape. The shape of the protrusion 6a is not limited as long as it is formed in a ring shape continuously in the circumferential direction along the pipe wall 5. The gas inlet pipe 1a is an example in which the porous member end 11a is on the same plane as the protrusion end 16a in the axial direction, as described in the configuration common to the gas inlet pipes 1a of the first embodiment to the gas inlet pipe 1f of the sixth embodiment.

[0033] <Effects of the gas blowing pipe 1a of the first embodiment> The configuration of the gas blowing pipe 1a of the first embodiment described above has the following advantages. As shown in Figures 2 and 3, the gas blowing pipe 1a has the protruding portion 6a formed in a ring shape that is continuous in the circumferential direction, which reduces the likelihood of the porous member 3a falling off at the tip. Furthermore, as shown in Figure 3, the porous member end portion 11a of the porous member 3a is exposed in a circumferentially continuous state at the pipe first end portion 7. Therefore, as shown in Figure 2(b), the gas G can be blown in a constant blowing manner regardless of the state in which the gas blowing pipe 1a is placed in the molten metal container 22.

[0034] In the example shown in FIG. 4 etc., the protruding portion 6a is doughnut-shaped and concentric with the center of the inner diameter of the pipe wall portion 5 of the pipe member 2a. In this case, even if the tip of the gas blowing pipe 1a is rotated, the gas G is blown in in the same manner. Furthermore, the pipe member 2a can be easily machined by simply drilling a circular hole in the first pipe end portion 7. The porous member 3a can be easily machined by simply forming a step portion 12a in the porous member end portion 11a to match the shape of the protruding portion 6a.

[0035] <Configuration of the gas blowing pipe 1b of the second embodiment> Next, the configuration of a gas inlet pipe 1b according to a second embodiment of the present invention will be described with reference to Figures 5 and 6. The gas inlet pipe 1b differs from the gas inlet pipe 1a in that the porous member end 11b protrudes further downstream than the first pipe end 7.

[0036] 5 and the like, similar to the example of the gas blowing pipe 1a shown in Fig. 3 and the like, the protruding portion 6b of the pipe member 2b is formed in a doughnut shape concentric with the center of the inner diameter of the pipe wall portion 5 of the pipe member 2a. The porous member end 11b has a cylindrical shape that matches the inner diameter of the protruding portion 6b, the step portion 12b is formed to be longer in the axial direction than the step portion 12a of the gas blowing pipe 1a, and the porous member end 11b protrudes further downstream than the protruding portion end 16b.

[0037] As with the gas inlet pipe 1a, the protruding portion 6b may have a shape other than a concentric circle with respect to the center of the inner diameter of the pipe wall portion 5. The gas inlet pipe 1b is an example in which the porous member end 11b protrudes axially downstream from the protruding portion end 16b, as explained in the configuration common to the gas inlet pipes 1a of the first embodiment to 1f of the sixth embodiment. The gas inlet pipes 1c of the third embodiment to 1f of the sixth embodiment described below show examples in which the porous member end 11 is formed on the same plane as the protruding portion end 16 in the axial direction, but the porous member end 11 may protrude downstream from the protruding portion end 16.

[0038] <Effects of the gas blowing pipe 1b of the second embodiment> The configuration of the gas blowing pipe 1b of the second embodiment described above has the following advantages. As shown in FIGS. 5 and 6, the protruding portion 6b of the gas blowing pipe 1b is formed in a circumferentially continuous ring shape, reducing the likelihood of the porous member 3b falling off at the tip. Furthermore, as shown in FIG. 5(b), the porous member 3b is exposed in a circumferentially continuous state at the first pipe end 7. This allows the gas G to be blown in a consistent manner regardless of the state in which the gas blowing pipe 1b is placed in the molten metal vessel 22. Furthermore, the porous member 3b protrudes downstream from the protruding portion 6b, increasing the surface area exposed to the molten metal 23, making it easier to blow the gas G. The pipe member 2b and porous member 3b of the gas blowing pipe 1b can be easily fabricated, similar to the gas blowing pipe 1a.

[0039] <Configuration of the gas blowing pipe 1c of the third embodiment> Next, the configuration of a gas blowing pipe 1c according to a third embodiment of the present invention will be described with reference to Figures 7 and 8. The gas blowing pipe 1c differs from the gas blowing pipe 1a in the shape of the protruding portion 6c and the porous member 3c at the first pipe end 7. The protruding portion 6c of the pipe member 2c in the gas blowing pipe 1c is formed continuously over at least a portion of the circumferential direction along the pipe wall portion 5. The porous member end 11c and the protruding portion end 16c are formed on the same plane in the axial direction.

[0040] Specifically, as shown in Fig. 8, the protrusions 6c are formed over a 180-degree range in the circumferential direction at the first pipe end 7. For the remaining 180-degree range, the protrusions 6c are not formed, and the first pipe end 7 is formed by the pipe wall portion 5. As shown in Fig. 8, the porous member 3c has a step portion 12c formed to match the shape of the protrusions 6c. Note that the protrusions 6c formed over a 180-degree range in the circumferential direction is just one example, and the angle at which the protrusions 6c are continuously formed may be other angles. Alternatively, the protrusions 6c are not limited to being formed in one location, and may be formed in multiple locations.

[0041] <Effects of the gas blowing pipe 1c of the third embodiment> The configuration of the gas blowing pipe 1c of the third embodiment described above has the following advantages: The gas blowing pipe 1c has the protruding portion 6c formed continuously over at least a portion of the circumference thereof, which reduces the likelihood of the porous member 3c falling off at the tip end.

[0042] <Configuration of the gas blowing pipe 1d of the fourth embodiment and the gas blowing pipe 1e of the fifth embodiment> Next, the configurations of a gas inlet pipe 1d of a fourth embodiment and a gas inlet pipe 1e of a fifth embodiment according to the present invention will be described with reference to Figures 9 and 10. The gas inlet pipe 1d and the gas inlet pipe 1e differ from the gas inlet pipe 1a in the shapes of the protrusions 6d, 6e and the porous members 3d, 3e at the first pipe end 7. The protrusions 6d, 6e are formed in plurality at equal angular intervals in the circumferential direction. The porous member end 11d and the protrusion end 16d, and the porous member end 11e and the protrusion end 16e, are formed on the same plane in the axial direction.

[0043] As shown in Fig. 9, the gas blowing pipe 1d has two protrusions 6d formed on a pipe member 2d at opposing positions spaced 180 degrees apart in the circumferential direction. In the example shown in Fig. 9, the protrusions 6d are each formed over a 90-degree range in the circumferential direction, which is the same angular range as the range in which no protrusions 6d are formed. In addition to this example, the range in which the protrusions 6d are formed may be greater or smaller than 90 degrees. The porous member 3d has a step 12d formed to match the shape of the protrusions 6d.

[0044] As shown in Fig. 10, the gas blowing pipe 1e has four protrusions 6e formed on a pipe member 2e at 90-degree intervals in the circumferential direction. In the example shown in Fig. 10, the angular range in which the protrusions 6e are formed in the circumferential direction is equal to the angular range in which they are not formed. In addition to this example, the intervals at which the protrusions 6e are formed may be greater or smaller than 90 degrees. Furthermore, the angular range in which the protrusions 6e are formed in the circumferential direction may differ from the angular range in which they are not formed. The porous member 3e has a step 12e formed to match the shape of the protrusions 6e.

[0045] <Effects of the gas blowing pipe 1d of the fourth embodiment and the gas blowing pipe 1e of the fifth embodiment> The configurations of the gas blowing pipe 1d of the fourth embodiment and the gas blowing pipe 1e of the fifth embodiment described above provide the following advantages. Because the protrusions 6d, 6e are formed at equal angular intervals in the circumferential direction, the gas blowing pipes 1d, 1e can reduce the likelihood of the porous members 3d, 3e falling off at their tip ends. Furthermore, the exposed portions of the porous members 3d, 3e and the portions covered by the protrusions 6d, 6e are equal in the circumferential direction at the first pipe end 7. Therefore, the gas blowing pipes 1d, 1e can blow the gas G in a consistent manner regardless of the state in which they are installed in the molten metal vessel 22. That is, regardless of the angle at which the tip of the gas blowing pipes 1d, 1e is rotated relative to the axial center C of the pipe members 2d, 2e when installed in the molten metal 23, the gas G is blown in the form of fine particles formed by the porous members 3d, 3e.

[0046] <Configuration of the gas blowing pipe 1f of the sixth embodiment> Next, the configuration of a gas inlet pipe 1f according to a sixth embodiment of the present invention will be described with reference to Fig. 11. The gas inlet pipe 1f differs from the gas inlet pipe 1a in the shape of the protruding portion 6f and the porous member 3f at the first pipe end 7. The protruding portion 6f of the pipe member 2f in the gas inlet pipe 1f forms a continuous chord in a direction perpendicular to the axial direction. The porous member end 11f and the protruding portion end 16f are formed on the same plane in the axial direction. The porous member 3f has a step portion 12f formed to match the shape of the protruding portion 6f.

[0047] Specifically, as shown in Fig. 11, the protrusion 6f passes through the axial center C and forms a rib-like string. Two strings are formed so as to be perpendicular to each other at the axial center C. Note that the example shown in Fig. 11 is not limiting, and the number of strings may be one, three or more, and the strings do not necessarily have to pass through the axial center C.

[0048] <Effects of the gas blowing pipe 1f of the sixth embodiment> The configuration of the gas blowing pipe 1f of the sixth embodiment described above has the following advantages. In the gas blowing pipe 1f, the protruding portions 6f form continuous chords in a direction perpendicular to the axial direction. Therefore, the protruding portions 6f can support the porous member 3f not only at the periphery of the pipe wall portion 5 but also radially inside, further reducing the likelihood of the porous member 3f falling off.

[0049] <Configurations and Effects Common to the Gas Injection Pipe 1g of the Seventh Embodiment to the Gas Injection Pipe 1k of the Tenth Embodiment> Next, a common configuration will be described for the gas blowing pipe 1g of the seventh embodiment to the gas blowing pipe 1k of the tenth embodiment with reference to Figures 12 to 17. In the gas blowing pipes 1g to 1k, the protruding portion end 16, which is the end of the downstream protruding portion 6, protrudes further downstream in the axial direction than the porous member end 11, which is the end of the downstream porous member 3. In addition to the effects of the common configuration, this configuration makes it easy to process the porous member end 11 at the pipe first end 7 because it only needs to be flat.

[0050] Furthermore, at the first pipe end 7, the porous member 3 and the protruding portion 6 are joined by a monolithic refractory 9. As in the example shown in FIG. 12 , at the first pipe end 7, the porous member 3 and the protruding portion 6 are joined at an axial joint 18 by a monolithic refractory 9 such as mortar between them. Furthermore, a joint 20 between the inner peripheral surface of the pipe wall portion 5 and the outer peripheral surface of the porous member 3 is also joined by a monolithic refractory 9 such as mortar. Therefore, in the gas injection pipe 1, the gap between the porous member 3 and the protruding portion 6 at the first pipe end 7 is filled, and it is possible to reduce the accumulation and aggregation of gas G, which causes bubbles to become larger.

[0051] <Configuration of the gas blowing pipe 1g of the seventh embodiment> Next, the configuration of a gas inlet pipe 1g according to a seventh embodiment of the present invention will be described with reference to Figures 12 to 14. The gas inlet pipe 1g differs from the gas inlet pipe 1c of the third embodiment already described in terms of the shape of the protruding portion 6g and the porous member 3g at the first pipe end 7. The protruding portion 6g of the pipe member 2g is formed in a continuous ring shape in the circumferential direction, and the protruding portion end 16g protrudes downstream beyond the first pipe end 7. The porous member end 11g is formed on the same plane as the first pipe end 7. The angular range in which the protruding portion 6g is formed is 180 degrees, and the angular range 13g in which the protruding portion 6g is not formed is also 180 degrees.

[0052] <Method of Using the Gas Injection Tube 1g of the Seventh Embodiment> Next, a method of using the gas blowing pipe 1g will be described with reference to FIG. 14. FIGS. 14(a) and 14(b) are diagrams illustrating how the state of the blown gas G differs depending on the method of use. FIG. 14(a) shows a case in which the gas blowing pipe 1g is installed with the protruding portion 6g facing downward at the first pipe end 7. That is, the case in which the gas blowing pipe 1g is installed with the angular range 13g in which the protruding portion 6g is not formed facing upward. In this case, the gas G is blown directly into the molten metal 23 from the porous member end 11g and rises, so the fine state formed by the porous member 3g is maintained.

[0053] FIG. 14(b) shows a case where the first end 7 of the gas blowing pipe 1g is installed with the protruding portion 6g facing upward. That is, the angle range 13g where the protruding portion 6g is not formed is facing downward. In this case, when the gas G is blown into the molten metal 23 from the end 11g of the porous member and rises, it is retained by the protruding portion 6g and aggregates, forming large bubbles, which rise intermittently. Because the state of the blown gas G differs depending on the installation state of the tip, it is desirable to install the gas blowing pipe 1g with the protruding portion 6g facing downward.

[0054] The configuration of the gas blowing pipe 1g of the seventh embodiment described above has the following advantages. Like the gas blowing pipe 1c, the gas blowing pipe 1g has the protruding portion 6g formed continuously in at least a portion of the circumferential direction, which reduces the likelihood of the porous member 3g falling off at the tip. Furthermore, if the gas blowing pipe 1g is installed so that the protruding portion 6g faces downward at the tip, the fine gas G formed by the porous member 3g can be blown directly into the molten metal 23.

[0055] <Configuration of the gas blowing pipe 1h of the eighth embodiment and the gas blowing pipe 1j of the ninth embodiment> Next, the configurations of a gas blowing pipe 1h of an eighth embodiment and a gas blowing pipe 1j of a ninth embodiment according to the present invention will be described with reference to Figures 15 and 16. The gas blowing pipe 1h and the gas blowing pipe 1j differ from the gas blowing pipe 1d of the fourth embodiment and the gas blowing pipe 1e of the fifth embodiment already described, respectively, in the shapes of the protrusions 6h, 6j at the pipe first end 7 and the porous members 3h, 3j.

[0056] As shown in FIG. 15, the gas blowing pipe 1h has two protruding portions 6h of a pipe member 2h formed at opposing positions 180 degrees apart in the circumferential direction, similar to the gas blowing pipe 1d. In the example shown in FIG. 15, the protruding portions 6h are each formed over a 90-degree range in the circumferential direction, which is the same angular range as the angular range 13h in which no protruding portion 6h is formed. A protruding portion end 16h of the protruding portion 6h is formed to protrude downstream from the first pipe end 7. In addition to this example, the range in which the protruding portion 6h is formed may be greater or less than 90 degrees. The porous member end 11h is formed on the same plane as the first pipe end 7 in the axial direction, regardless of the shape of the protruding portion 6h.

[0057] As shown in FIG. 16, the gas blowing pipe 1j has four protrusions 6j formed on a pipe member 2j at 90-degree intervals in the circumferential direction, similar to the gas blowing pipe 1e. Protrusion end portions 16j of the protrusions 6j are formed so as to protrude downstream from the first pipe end portion 7. The porous member end portion 11j of the porous member 3j is formed on the same plane as the first pipe end portion 7 in the axial direction, regardless of the shape of the protrusions 6j. In the example shown in FIG. 16, the angular ranges in which the protrusions 6j are formed in the circumferential direction and the angular ranges 13j in which they are not formed are equivalent. In addition to this example, the angular ranges in which the protrusions 6j are formed in the circumferential direction and the angular ranges 13j in which they are not formed may be different.

[0058] <Effects of the gas blowing pipe 1h of the eighth embodiment and the gas blowing pipe 1j of the ninth embodiment> The configurations of the gas blowing pipe 1h of the eighth embodiment and the gas blowing pipe 1j of the ninth embodiment described above provide the following advantages. Because the protrusions 6h, 6j are formed at equal angular intervals in the circumferential direction, the gas blowing pipes 1h, 1j can reduce the likelihood of the porous members 3h, 3j falling off at their tip ends. Furthermore, the porous members 3h, 3j exposed at the first pipe end 7 have uniform angular ranges 13h, 13j in the circumferential direction, where the portions exposed inside the protrusions 6h, 6j are equal to the portions exposed inside the pipe wall 5, i.e., where the protrusions 6h, 6j are not formed. Therefore, the gas blowing pipes 1h, 1j can blow the gas G in a consistent manner regardless of the state in which they are installed in the molten metal container 22.

[0059] The protrusions 6h, 6j protrude downstream beyond the first pipe end 7, but are formed at equal angles in the circumferential direction. The gas blowing pipes 1h, 1j have angular ranges 13h, 13j within which the gas G is not retained by the protrusions 6h, 6j when it is blown upward, regardless of the state in which the tip of the gas blowing pipe 1h, 1j is placed in the molten metal 23. Furthermore, by positioning the angular ranges 13h, 13j within which the protrusions 6h, 6j are not formed on the upper side when the tip of the gas blowing pipe 1h, 1j is placed in the molten metal 23, the effect of preventing retention can be further enhanced. Therefore, fine gas G formed by the porous members 3h, 3j can be blown directly into the molten metal 23.

[0060] <Configuration of the gas blowing pipe 1k according to the tenth embodiment> Next, the configuration of a gas inlet pipe 1k according to a tenth embodiment of the present invention will be described with reference to Fig. 17. The gas inlet pipe 1k differs from the gas inlet pipe 1f of the sixth embodiment already described in terms of the shape of the protruding portion 6k and the porous member 3k at the first pipe end 7. The protruding portion 6k of the pipe member 2k in the gas inlet pipe 1k forms a continuous chord in a direction perpendicular to the axial direction. The protruding portion end 16k of the protruding portion 6k is formed so as to protrude downstream from the first pipe end 7. The porous member end 11k is formed on the same plane as the first pipe end 7.

[0061] Specifically, as shown in Fig. 17, the protrusion 6k passes through the axial center C and has a rib-like chord formed thereon. Two chords are formed so as to be perpendicular to each other at the axial center C. Note that the example shown in Fig. 17 is not limiting, and the number of strings may be one, three or more, and the strings do not necessarily have to pass through the axial center C.

[0062] <Effects of the gas blowing pipe 1k of the tenth embodiment> The configuration of the gas blowing pipe 1k of the tenth embodiment described above has the following advantages. In the gas blowing pipe 1k, the protruding portion 6k forms a continuous chord in a direction perpendicular to the axial direction. Therefore, the protruding portion 6k can support the porous member 3k not only at the periphery of the pipe wall portion 5 but also inside in the radial direction, further reducing the possibility of the porous member 3k falling off.

Explanation of Symbols

[0063] 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1j, 1k Gas injection tubes 2, 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2j, 2k Pipe members 3, 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3j, 3k Porous members 4 Gas pipe 5 Pipe wall part 6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6j, 6k Protrusions 7 First end of the pipe 8 Second end of the pipe 9 Refractory 11, 11a, 11b, 11c, 11d, 11e, 11f, 11g, 11h, 11j, 11k Ends of the porous member 16, 16a, 16b, 16c, 16d, 16e, 16f, 16g, 16h, 16j, 16k Ends of the protrusion 22 Molten metal container 23 Molten metal 24 Connecting member G Gas

Claims

1. A gas injection pipe that is immersed in the molten metal in the molten metal container and injects gas, In the gas flow direction, the side where the gas is supplied is defined as an upstream side, and the side where the gas is injected into the molten metal is defined as a downstream side, a cylindrical pipe member having a first pipe end portion on the downstream side and a second pipe end portion on the upstream side; a porous member formed inside the tubular member; a gas pipe connected to the second end of the pipe member via a connecting member; With respect to a pipe wall portion that forms the outer periphery of the pipe member, the center side of the pipe member is defined as the inner side, and the side opposite to the center is defined as the outer side, the direction connecting the first pipe end portion and the second pipe end portion is defined as the axial direction, and the direction perpendicular to the axial direction is defined as the radial direction, the pipe member has a predetermined thickness in the axial direction at the first pipe end portion, and includes a protrusion protruding inward from the pipe wall portion; the pipe member, the pipe wall portion, and the protrusion portion are integrally formed, At the first end of the tube, the porous member is partially exposed and partially covered by the protrusion; a gas blowing pipe that is immersed in the molten metal in the molten metal vessel, and when the gas is introduced into the gas pipe, the gas passes through the porous member and is blown into the molten metal vessel;

2. A gas injection pipe that is immersed in molten metal in a molten metal container and injects gas, In the gas flow direction, the side where the gas is supplied is defined as an upstream side, and the side where the gas is injected into the molten metal is defined as a downstream side, a cylindrical pipe member having a first pipe end portion on the downstream side and a second pipe end portion on the upstream side; a porous member formed inside the tubular member; a gas pipe connected to the second end of the pipe member via a connecting member; With respect to a pipe wall portion that forms the outer periphery of the pipe member, the center side of the pipe member is defined as the inner side, and the side opposite to the center is defined as the outer side, the direction connecting the first pipe end portion and the second pipe end portion is defined as the axial direction, and the direction perpendicular to the axial direction is defined as the radial direction, The pipe member has a predetermined thickness in the axial direction at the first pipe end portion, and a protrusion protruding inward from the pipe wall portion is formed, the protrusion and the porous member are joined at the axial joint at the first end of the pipe, the porous member has a structure in which a distance between the joint and the downstream end in the axial direction is shorter than a distance between the joint and the upstream end, The porous member end portion, which is the end portion of the porous member on the downstream side, is on the same plane as the protruding portion end portion, which is the end portion of the protruding portion on the downstream side, in the axial direction, or protrudes to the downstream side; At the first end of the tube, the porous member is partially exposed and partially covered by the protrusion; a gas blowing pipe that is immersed in the molten metal in the molten metal vessel, and when the gas is introduced into the gas pipe, the gas passes through the porous member and is blown into the molten metal vessel;

3. A gas injection pipe that is immersed in molten metal in a molten metal container and injects gas, In the gas flow direction, the side where the gas is supplied is defined as an upstream side, and the side where the gas is injected into the molten metal is defined as a downstream side, a cylindrical pipe member having a first pipe end portion on the downstream side and a second pipe end portion on the upstream side; a porous member formed inside the tubular member; a gas pipe connected to the second end of the pipe member via a connecting member; With respect to a pipe wall portion that forms the outer periphery of the pipe member, the center side of the pipe member is defined as the inner side, and the side opposite to the center is defined as the outer side, the direction connecting the first pipe end portion and the second pipe end portion is defined as the axial direction, and the direction perpendicular to the axial direction is defined as the radial direction, The pipe member has a predetermined thickness in the axial direction at the first pipe end portion, and a protrusion protruding inward from the pipe wall portion is formed, The porous member has a step portion formed at the first end of the pipe, the step portion being recessed radially inward to match the shape of the protruding portion, In the axial direction, the length of the step portion is shorter than the length of the portion of the porous member other than the step portion, The porous member end portion, which is the end portion of the porous member on the downstream side, is on the same plane as the protruding portion end portion, which is the end portion of the protruding portion on the downstream side, in the axial direction, or protrudes to the downstream side; At the first end of the tube, the porous member is partially exposed and partially covered by the protrusion; a gas blowing pipe that is immersed in the molten metal in the molten metal vessel, and when the gas is introduced into the gas pipe, the gas passes through the porous member and is blown into the molten metal vessel;

4. A gas injection pipe that is immersed in molten metal in a molten metal container and injects gas, In the gas flow direction, the side where the gas is supplied is defined as an upstream side, and the side where the gas is injected into the molten metal is defined as a downstream side, a cylindrical pipe member having a first pipe end portion on the downstream side and a second pipe end portion on the upstream side; a porous member formed inside the tubular member; a gas pipe connected to the second end of the pipe member via a connecting member; With respect to a pipe wall portion that forms the outer periphery of the pipe member, the center side of the pipe member is defined as the inner side, and the side opposite to the center is defined as the outer side, the direction connecting the first pipe end portion and the second pipe end portion is defined as the axial direction, and the direction perpendicular to the axial direction is defined as the radial direction, The pipe member has a predetermined thickness in the axial direction at the first pipe end portion, and a protrusion protruding inward from the pipe wall portion is formed, At the first end of the tube, the porous member is partially exposed and partially covered by the protrusion; The porous member end portion, which is the end portion of the porous member on the downstream side, protrudes downstream in the axial direction relative to the protruding portion end portion, which is the end portion of the protruding portion on the downstream side, a gas blowing pipe that is immersed in the molten metal in the molten metal vessel, and when the gas is introduced into the gas pipe, the gas passes through the porous member and is blown into the molten metal vessel;

5. A gas injection pipe that is immersed in molten metal in a molten metal container and injects gas, In the gas flow direction, the side where the gas is supplied is defined as an upstream side, and the side where the gas is injected into the molten metal is defined as a downstream side, a cylindrical pipe member having a first pipe end portion on the downstream side and a second pipe end portion on the upstream side; a porous member formed inside the tubular member; a gas pipe connected to the second end of the pipe member via a connecting member; With respect to a pipe wall portion that forms the outer periphery of the pipe member, the center side of the pipe member is defined as the inner side, and the side opposite to the center is defined as the outer side, the direction connecting the first pipe end portion and the second pipe end portion is defined as the axial direction, and the direction perpendicular to the axial direction is defined as the radial direction, The pipe member has a predetermined thickness in the axial direction at the first pipe end portion, and a protrusion protruding inward from the pipe wall portion is formed, At the first end of the tube, the porous member is partially exposed and partially covered by the protrusion; The protruding portion end portion, which is the end portion of the protruding portion on the downstream side, protrudes downstream further than the porous member end portion, which is the end portion of the porous member on the downstream side, a gas blowing pipe that is immersed in the molten metal in the molten metal vessel, and when the gas is introduced into the gas pipe, the gas passes through the porous member and is blown into the molten metal vessel;

6. 6. The gas injection pipe according to claim 1, wherein the protrusion is formed continuously in a ring shape in the circumferential direction along the pipe wall.

7. 6. The gas injection pipe according to claim 1, wherein the protrusion is formed continuously over at least a portion of the circumferential direction along the pipe wall.

8. 6. The gas blowing pipe according to claim 1, wherein the porous member and the protruding portion are joined together at the first end of the pipe by a monolithic refractory material.

9. A gas injection pipe that is immersed in molten metal in a molten metal container and injects gas, In the gas flow direction, the side where the gas is supplied is defined as an upstream side, and the side where the gas is injected into the molten metal is defined as a downstream side, a cylindrical pipe member having a first pipe end portion on the downstream side and a second pipe end portion on the upstream side; a porous member formed inside the tubular member; a gas pipe connected to the second end of the pipe member via a connecting member; With respect to a pipe wall portion that forms the outer periphery of the pipe member, the center side of the pipe member is defined as the inner side, and the side opposite to the center is defined as the outer side, the direction connecting the first pipe end portion and the second pipe end portion is defined as the axial direction, and the direction perpendicular to the axial direction is defined as the radial direction, The pipe member has a predetermined thickness in the axial direction at the first pipe end portion, and a protrusion protruding inward from the pipe wall portion is formed, At the first end of the tube, the porous member is partially exposed and partially covered by the protrusion; the protrusion is formed continuously along at least a portion of the pipe wall in a circumferential direction, The protrusions are formed at equal angular intervals in the circumferential direction, a gas blowing pipe that is immersed in the molten metal in the molten metal vessel, and when the gas is introduced into the gas pipe, the gas passes through the porous member and is blown into the molten metal vessel;

10. A gas injection pipe that is immersed in a molten metal in a molten metal container and injects gas, In the gas flow direction, the side where the gas is supplied is defined as an upstream side, and the side where the gas is injected into the molten metal is defined as a downstream side, a cylindrical pipe member having a first pipe end portion on the downstream side and a second pipe end portion on the upstream side; a porous member formed inside the tubular member; a gas pipe connected to the second end of the pipe member via a connecting member; With respect to a pipe wall portion that forms the outer periphery of the pipe member, the center side of the pipe member is defined as the inner side, and the side opposite to the center is defined as the outer side, the direction connecting the first pipe end portion and the second pipe end portion is defined as the axial direction, and the direction perpendicular to the axial direction is defined as the radial direction, The pipe member has a predetermined thickness in the axial direction at the first pipe end portion, and a protrusion protruding inward from the pipe wall portion is formed, At the first end of the tube, the porous member is partially exposed and partially covered by the protrusion; The protrusion has a chord formed thereon that is continuous in a direction perpendicular to the axial direction, a gas blowing pipe that is immersed in the molten metal in the molten metal vessel, and when the gas is introduced into the gas pipe, the gas passes through the porous member and is blown into the molten metal vessel;

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