Support structure of furnace lid

Abstract

To provide a support structure of a furnace lid of a ladle refining furnace with high reliability.SOLUTION: In a support structure, a furnace lid is arranged at an upper part opening of a ladle of a ladle refining furnace. The support structure includes: a cylinder rod moving up / down in the vertical direction at a position separated from a side peripheral part of the ladle; and a locking piece at the outside of the movement path of the cylinder rod, for restricting the lower limit movement position of the furnace lid. The cylinder rod is provided at a plurality of positions in the vicinity of the side peripheral part of the ladle by being paired up with the locking piece. At a top part of the cylinder rod, a receiving part provided at a peripheral edge part of the furnace lid is placed, and the furnace lid can move up / down on the vertical line of the upper part opening of the ladle. The receiving part is placed on the locking piece, and when the top part of the cylinder rod is separated downward of the receiving part, a furnace lid is arranged at a position spaced a predetermined interval from an upper side of the upper part opening of the ladle.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a support structure for a furnace roof of a ladle refining furnace. [Background technology]

[0002] A ladle refining furnace (LF) is a device used for reduction refining to deoxidize, desulfurize, and remove non-metallic inclusions. Molten steel is loaded and unloaded through the top opening of the ladle-shaped furnace body (ladle). During refining, a furnace lid is placed over the top opening, and electrodes are inserted through holes in the lid to refine the molten steel. Therefore, a device for placing the lid on the furnace body is required.

[0003] For example, Patent Document 1 discloses a furnace cover lifting device for a ladle refining furnace that raises and lowers the cover in a horizontal position by synchronously operating two cylinders. A plurality of guide members that guide the cover as it rises and falls are installed at separate positions along the outer periphery of the furnace cover, and a member that is inserted vertically into the guide members and guided is provided on the cover. One end of a chain is attached to each side of the cover, and the other end is attached to a cylinder rod, driving the chain to raise and lower the cover along the guide members. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 62-250114 Summary of the Invention [Problem to be solved by the invention]

[0005] During refining operations in a ladle refining furnace, arc discharge generates splashes of molten metal, which fly to the inside of the furnace lid, solidify, and adhere to it. Therefore, if the lid is placed on the furnace body and tightly adheres to it, the molten metal will adhere and solidify along the contact area, making it impossible to open the lid. Even if the lid opens, the solidified metal will fall onto the molten metal, changing its composition. Therefore, it is preferable to operate the furnace lid with a slight gap from the furnace body. In this case, in a support mechanism that supports the lid with a cylinder mechanism, the weight of the heavy lid continues to be applied to the cylinder, which reduces the durability of the cylinder and poses the risk of damage, which can seriously hinder operation.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a highly reliable support structure for a furnace cover of a ladle refining furnace. [Means for solving the problem]

[0007] The present invention provides a support structure for placing a furnace cover on the upper opening of a ladle of a ladle refining furnace, comprising a cylinder rod that moves up and down vertically at a position spaced apart from the side periphery of the ladle, and a locking piece that is outside the movement path of the cylinder rod and determines the lower limit movement position of the furnace cover, the cylinder rod and the locking piece being provided as a pair at multiple positions near the side periphery of the ladle, a receiving part provided on the peripheral part of the furnace cover is placed on the top of the cylinder rod, allowing the furnace cover to move up and down on a vertical line with the upper opening of the ladle, and when the receiving part is placed on the locking piece and the top of the cylinder rod is spaced apart below the receiving part, the furnace cover is positioned at a position a predetermined distance above the upper opening of the ladle.

[0008] According to this feature, the furnace cover can be stably positioned in a predetermined position relative to the ladle without applying an excessive load to the cylinder rod, thereby achieving high reliability.

[0009] In the above-described invention, the cylinder rod and the locking piece may be mounted on a base that is electrically insulated from the ladle, which prevents sparks from the electrodes and ensures high reliability.

[0010] In the above-mentioned invention, the locking piece may be attached to the base so that its upper and lower fixing positions can be changed to adjust the predetermined distance. This feature prevents sparks from occurring between the ladle and the furnace cover, and ensures high reliability. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a side view of a ladle smelting furnace and a furnace roof support structure. [Figure 2] FIG. 2 is a top view of the furnace hood and the support structure for the furnace hood. [Figure 3] 10A and 10B are side views of the support portion when the cylinder rod is raised and lowered, respectively. [Figure 4] FIG. 2 is a side cross-sectional view of a main part of the support part. DETAILED DESCRIPTION OF THE INVENTION

[0012] A support structure for a furnace roof of a ladle refining furnace as one embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG.

[0013] As shown in Fig. 1, the ladle smelting furnace 1 includes a ladle 2, which is a substantially cylindrical container with a bottom, and a furnace lid 3, which is substantially circular in top view and is disposed at its upper opening 2a. The furnace lid 3 is supported by a support 10 disposed at a position spaced apart from the side periphery of the ladle 2, and can be moved up and down by the operation of the support 10.

[0014] Referring also to Figure 2, the furnace cover 3 has multiple arms 4 fixed to its upper surface that extend toward the periphery, with receiving parts 5 at the tips of the arms located on its periphery. The receiving parts 5 are placed on supports 10 that are arranged at multiple positions near the side periphery of the ladle 2. This allows the furnace cover 3 to be supported by the supports 10. Here, there are four combinations of arms 4, receiving parts 5, and supports 10. The supports 10 are fixed onto beams 11 that extend substantially horizontally, and the beams 11 support the load received from the furnace cover 3. The beams 11 may be, for example, H-shaped steel.

[0015] As shown in FIG. 3(a), the support 10 is fixed to a beam 11 and a base 12 fixed to its upper surface. It includes a guide 16 and a hydraulic cylinder drive unit 13. The drive unit 13 includes a cylinder 13a fixed to the base 12 and a cylinder rod 13b that moves up and down vertically relative to the cylinder 13a. A contact member 14 is fixed to the tip of the cylinder rod 13b, forming the top of the cylinder rod 13b. When the cylinder rod 13b is moved upward, the contact member 14 contacts the underside of a receiving bracket 6 fixed to the underside of the receiving part 5, and the receiving part 5 is placed on the receiving bracket 6. At this time, the contact member 14, which is the top of the cylinder rod 13b, supports the furnace lid 3 via the receiving part 5 and the arm 4. In other words, the up and down movement of the cylinder rod 13b allows the furnace lid 3 to move up and down along the vertical line of the upper opening 2a.

[0016] On the other hand, the guide 16 extends vertically along the outer edge of the path along which the receiving part 5 moves up and down, and is arranged so as to close two outer faces of the receiving part 5 (outward from the furnace lid 3). The guide 16 has a plate-like body 16a arranged on the inside to guide the up and down movement of the receiving part 5, and is provided with a rib 16b on the back surface of the plate-like body 16a to reinforce the plate-like body 16a. In addition, a locking piece 15 is fixed to the plate-like body 16a so as to protrude inward.

[0017] As shown in FIG. 1(b), the locking piece 15 is positioned outside the vertical movement path of the cylinder rod 13b and the abutment member 14 and is arranged to abut against the receiving bracket 6 when the lid 3 is lowered. When the receiving bracket 6 abuts against the locking piece 15 and is placed on it together with the receiving part 5, the locking piece 15 prevents further lowering, and the lid 3 is supported on the locking piece 15. In other words, the locking piece 15 determines the lowest movement position of the lid 3. This lowest movement position is determined so that the lid 3 is positioned at a predetermined distance above the upper opening 2a of the ladle 2. This predetermined distance is determined so as to prevent the lid 3 from adhering to the ladle 2 even if molten metal splashes during refining, and to prevent the falling of solidified metal from changing the composition of the molten metal.

[0018] With the support structure for the furnace cover 3 described above, the cover 3 can be raised by driving the cylinder rod 13b upward, allowing molten metal to be loaded and unloaded through the upper opening 2a of the ladle 2. On the other hand, the cover 3 can also be lowered by driving the cylinder rod 13b downward. When the cover 3 reaches its lowest limit, it is supported by the locking piece 15. At this time, the abutment member 14 at the tip of the cylinder rod 13b moves away from the receiving bracket 6, preventing a load from being applied to the cylinder rod 13b. In other words, the cover 3 can be stably positioned relative to the ladle 2 without applying an excessive load to the cylinder rod 13b, ensuring high reliability.

[0019] It is also preferable that the upper and lower fixing positions of the locking pieces 15 are variable so that the above-mentioned predetermined interval can be adjusted. For example, the locking pieces 15 are fixed to the plate-like body 16a by fastening bolts using fastening holes, and a plurality of fastening holes are provided at different upper and lower fixing positions.

[0020] As shown in Figure 4, the horizontal position of the receiving part 5 can also be stabilized by the shape of the contact surface between the contact member 14, which is the top of the cylinder rod 13b, and the receiving bracket 6 of the receiving part 5. The upper surface 14a of the contact member 14 is made convex upward, and a recess 6a with an upward convex curved surface is provided in the center of the lower surface of the receiving bracket 6. It is preferable to make the radius of curvature of the upper surface 14a smaller than the radius of curvature of the recess 6a. With this shape, the horizontal position of the receiving part 5 is adjusted so that the upper surface 14a is positioned deepest into the recess 6a each time the contact member 14 is made to contact the receiving bracket 6, thereby stably maintaining the horizontal position of the furnace lid 3.

[0021] It is preferable that the beam 11 and the base 12 are configured so as to be electrically insulated from the ladle 2. The insulation can prevent sparks from the electrodes inserted into the furnace cover 3.

[0022] While typical embodiments of the present invention and modifications based thereon have been described above, the present invention is not necessarily limited to these, and a person skilled in the art will be able to find various alternative embodiments and modifications without departing from the spirit of the present invention or the scope of the appended claims. [Explanation of symbols]

[0023] 1 Ladle smelting furnace 2 Ladle 2a Top opening 3 Hearth cover 4 Arm 5 Receiving 10 Support part

Claims

1. A support structure for placing a furnace cover on an upper opening of a ladle of a ladle refining furnace, a cylinder rod that moves up and down in a vertical direction at a position spaced apart from the side periphery of the ladle; and a locking piece that is located outside the movement path of the cylinder rod and determines the lower limit movement position of the furnace cover, a support structure for a furnace lid of a ladle refining furnace, characterized in that the cylinder rods are provided in pairs with the locking pieces at a plurality of positions near the side periphery of the ladle, a receiving portion provided on the peripheral portion of the furnace lid is placed on the top of the cylinder rod, allowing the furnace lid to move up and down on a vertical line with the upper opening of the ladle, and when the receiving portion is placed on the locking piece and the top of the cylinder rod is moved away below the receiving portion, the furnace lid is positioned at a position above the upper opening of the ladle at a predetermined distance.

2. 2. The support structure for a furnace cover of a ladle refining furnace according to claim 1, wherein the cylinder rod and the locking piece are mounted on a base that is electrically insulated from the ladle.

3. 3. A support structure for a furnace cover of a ladle refining furnace according to claim 2, wherein the locking pieces are attached to the base so that their upper and lower fixing positions can be changed to adjust the predetermined interval.

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