SE425866B - LOCK FOR AN ELECTRIC LIGHT BAG - Google Patents

Description

7903587-9 2 From the literature, a lid for an electric arc furnace is known, namely from the "Fachberichte H" ttenpraxis Metallverarbeitung "1978, pages 77 - 81, which lid consists of a refractory inner part and a water-cooled one outer part. The water-cooled outer part consists of trapezoidal segments in a pipe / weld construction. The pipe / weld construction provides one forced control of the cooling water in order to avoid the occurrence of cushions. The segments are suspended in a truss construction.

Against the background of the according to German DS 2 639 378 consisting of segments the inner part of the present invention has for its object to provide a of chilled segments consisting of lids, which on the oven side does not require any refractory lining, and which next to the electrodes is specially designed resistant. Thus, the lid should be intended to on a special be able to absorb radial shock loads, which are caused by horizontal sontal movements of the electrodes.

This object is solved according to the invention by the inner part consists of three anchor-like segments, each of which is circularly encloses two electrodes and ear designed for forced control of the coolant, and wherein the surfaces facing the melt to the The coolant-permeable segments are designed with only electrically thin insulating protective layer. According to a preferred embodiment, each anchor-shaped segment formed with several chambers, each cooling chamber leading to the center of the oven. Each cold room contains a forced control, suitably in in the form of guide plates, so that the cooling water is safely led into each segment zone. It is particularly advantageous that an anchor-shaped segment is formed with two separate cold rooms, the partition wall extending radially out from the center of the lid. In each partition, the joint plates are there which are directed towards the arranged opening for passage of the electrodes. Thus, they run in the vicinity of the electrode bushings arranged the articulated plates approximately concentrically with the opening, while the ell further away existing joint plates are more closed out in their curvature.

The water inlets and water outlets are arranged in this way with regard to the oven tipping movement, that the water outlet is arranged at a higher level if possible than the water intake. This avoids the appearance of steam cushions. The the anchor-shaped segments are insulated against the electrodes by a fire solid lining. The radial thickness of this liner can be exemplified. be l0 - 20 cm, and the refractory lining can be achieved with 7903587-9 by means of bricks, which are suspended against the anchor-shaped segments.

The thin electrically conductive protective layer on the surface of the cooling the elements facing the melt are preferably provided by a 0.5 - 3 mm thick layer of a ceramic oxide material. This protective layer prevents electrical contact from the scrap area, which could lead to a premature wear of the cooling elements.

The individual segments are electrically isolated from each other and preferably also from the suspension means in the supporting structure.

In the segment area, the insulation can be formed by strips of elastic and heat durable material. In an advantageous embodiment, they have ments arranged the strips a thickness of 2 - 5 cm. A suitable material is a fiber mat of asbestos. These strips have several different functions. The are first of all necessary to provide an electrical insulation, since eddy current formation can cause damage to the cooling element. ten. In addition, the strips serve as damping means, which depending on their elasticity can absorb shock loads. The insulation strips provide at the same time a seal between the segments among themselves. The strips follow the lid structure such as a suspended, arched structure. According to a preferred embodiment, the load-bearing structure (truss structure) is formed with an outer and an inner support ring, which are connected via support means with each other, three collar arms extending inwardly from the interior the bearing ring. Each segment is suspended separately in the support structure. Suitable the anchor-shaped segments are suspended at three points, namely at collar arm and with two suspension points in the support ring. The outer ones the segments can suitably be suspended in two pieces located internally points and two externally located points in the support structure.

It has proved advantageous that the suspension means for the cooling elements are so constructed that there is no current transfer from the cooling the elements of the supporting structure. This is accomplished by the suspension takes place via insulated bolts and bushings. Furthermore, it is beneficial if the suspension points located closer to the center of the furnace to the segments lead through elongate holes, so that the suspension means can move in radial suffered at thermal stresses, and so that you get an elasticity in the whole system.

As mentioned above, the cooling elements are suitably covered by a refractory layer with a thickness of, for example, 5 to 10 cm. This layer prevents short-circuiting which could arise from dust deposits, and it improves the tightness of the lid. 79035-87-9 The construction according to the invention opens up an opportunity to produce set the inner part to the lid of water-cooled segments, which have a long sustainability. For this purpose, it is essential that between the the anchor-shaped step arranged has an optimally small width and with optimally low stability, and that this step is intensively flowed by coolant. The strong flow of coolant is achieved with using the device with hinge plates. At the same time, it causes anchorage the construction has the advantage that radial impact loads, which can caused by horizontal movements in the electrodes, the wells of each are intercepted individual segment. The insulation strips arranged between the segments are judged couple of such shock loads. Because the cooling water is under forced control caused to flow around the electrode openings, a uniform cooling is obtained of the electrode zones. Due to the anchor-shaped construction, the cooling takes place all the way to the center of the lid. The segments can not be damaged due to vortex formation, as the segments are electrically isolated from each other.

It also means an advantage that the suspension is effected by a lattice shaped structure, as this suspension provides a static stability tet. The suspension also allows the absorption of radial shock loads, since the long holes in the suspension allow a movement of the individual segments.

The invention will now be described in more detail with reference to attached drawings, which refer to an embodiment. On the drawings shows figure 1 is a top view of the lid according to the invention, and figure 2 is one section along the line II - II in figure l.

The lid consists mainly of an inner part, which is made up of three pieces anchor-shaped segments 2. Radially outwards is an annular outer part connected, which consists of a plurality of trapezoidal segments 3. Each segments 2, 3 in the outer part and the inner part are separately suspended in a grid similar support structure 1. The support structure rests with its outer ring 4 on top of the oven wall 5.

The support structure 1 consists in more detail of the outer ring 4 and the inner ring 6. Outer ring 4 and ring 6 are interconnected through beams 7. From the inner ring 6 extend three pieces of collar arms 8 radially inwards, and these collar arms 8 are distributed at an angle of 180 °.

At their front or inner ends, each collar arm is provided with a longitudinal hole 9 for suspending an anchor-shaped segment 2 in each collar arm. . _ ___ ”. __..__._... _..___ í ...._._...._._..., .., ._._....._.__. 7903587-9 Each anchorage segment 2 is suspended at three points. Two of the suspension points are located on the inner collar ring 6. Where and one of the trapezoidal segments 3 to the outer part are suspended in two beams 7. Each beam 7 has an outer suspension point 10 and an internal suspension point ll. The inner suspension point ll is designed as a long hole to enable radial movement.

As the horizontal projection in Figure 1 shows encloses each one of the anchor-shaped segments 2 on a semicircular sweet two-piece electrode openings, so that each anchor-shaped segment 2 with a wide, coolant-permeable step is arranged between two electrodes. Each segment 2 is divided into two equally large cold rooms by means of partially running partitions 13. Each cold room is designed with a water inlet 14 and a water outlet 15. For forced control of the water is available a number of articulated plates 16. The first articulated plate runs essentially semi-circular kel-shaped and extends from the water intake l4 all the way into the space between the two electrodes. This construction provides intense cooling in this space or step.

Between the anchor-shaped segments 2 and the opening for the electrodes an approximately 15 cm thick refractory liner 17 is provided. Infodríngen may consist of separate bricks, which are suspended in the anchor-shaped segment 2.

The anchor-shaped segment 2 and the segment-shaped cooling elements are insulated from each other by insulating tape 18 of asbestos. These asbestos- strips may, for example, have a thickness of 3 cm. On the one hand, they serve to to provide electrical insulation, partly also to provide a damping of shock loads. As shown in Figure 2, the belts 18 preferably have T shaped cross-section and supports the curved construction through its spatial shape on the segmented lid. Between the outer ring 4 and the cooling segment 3, a refractory liner 19 is provided. The cooling segment 3 ends in diell led In front of the lining 20 of the oven wall 5. This prevents that water in the event of water damage to the lid penetrates between the oven wall 5 and the associated lining 20.

The water-cooled segments have one side facing the melt layers of ceramic oxide with a thickness of only 0.5 - 3 mm In order to come an electrical insulation of the water-cooled segments against it in the kiln scrap. The lid therefore consists practically exclusively 7903587-9 O'\ Of importance for sustainability is that these water-cooled segments are arranged to forcibly direct the water, which spirit of water-cooled segments. is done with the help of guide plates. At the outer segments, the articulated plates run practically concentric with each other, but they are arranged so that the alternating ones extend from the radially extending side walls, and so that a transfer chamber is formed For the cooling water at these side walls.

With regard to the tilting movement of the lid, the cooling water intake is arranged at one low-lying place to the segments. ' At the anchor-shaped segments of the inner part a forced pipe of cooling water all the way to the middle of the lid likewise with the help of guide plates, which lead all the way into the anchor part between the electrodes. Water- the inlet and the water outlet are arranged in such a way with regard to the tilting movement of the lid, that the outlet is as far as possible arranged at a higher level than intake. Thereby an intense and uniform is achieved cooling of the electrode area.

Claims (2)

n. __-......._. A lid for an electric arc furnace with an annular outer part consisting of segments (3), which are flowed through by coolant, and an inner part, which consists of segments (2), which are passed through of coolant, and the inner part is formed with refractory insulated openings (17) for the passage of electrodes, and wherein the segments (2, 3) are electrically insulated from each other and are suspended in a support structure, which supports against the furnace wall (5 ), characterized in that the inner part consists of three anchor-shaped segments (2), each enclosing two electrodes on a semicircular sweet, and which are formed with a forced guide (16) for coolant, and in that it against the melt facing the surface to the segments flowing through coolant (2, 3) are provided with only a thin electrically insulating protective layer. Lid according to claim 1, characterized in that each of the anchorage segments (2) of the inner part is formed with a plurality of compartments, each such compartment, which is formed with forced control (16) for cooling water, extending all the way to the middle of the oven.