DE2302205C2 - Refractory lining for a circular melting vessel - Google Patents

Description

- One point (34) is determined by the intersection of a connecting line (24, 24 ') between the one lateral inner edge (C) of the stone (22) and the center (28) of the circular brickwork with the circumference of a circle (30) about this center (28), _2i whose radius is half the sum of the inner radius ^r of the Ausmaue ung,

- The other point (D) is defined by the other lateral inner edge of the stone (22).

30th

The invention relates to a refractory brick lining a circular vessel for molten metal, in particular a lining of an inductively heated one Furnace, with stacked, arched, arched stones.

Refractory linings of the type indicated above are known and are shown in the attached FIGS. 1 and 2 shown. In these known linings for circular metallurgical vessels, the abutting side edge surfaces of adjacent stones each run in the plane of a corresponding radius of the circular vessel. At corresponding temperatures, thermal expansion forces occur. which run perpendicular to the abutting edge surfaces of the stones, with the result that an undesirable increase _{Μ of} the furnace diameter occurs as a result of the thermal expansion. As a consequence of such an increase in circumference, dangers for an induction coil surrounding the refractory furnace lining are created and the occurrence of cracks in the lining is favored.

The invention is based on the object of providing a refractory lining of the known type train that the harmful consequences of thermal expansion can be largely reduced.

This is the job of a refractory brick lining of the type specified in the preamble of claim 1 solved in that the laterally mutually abutting bonds Edge surfaces of the stones such an acute angle inclined in the same direction with the Form the radius of the vessel that with thermal expansion of the Brick lining the edge surfaces of the stones slide against each other.

The rnii aid of the invention tangible technical Progress is primarily to be seen in the fact that, as a result of the above-mentioned design of the laterally abutting edge surfaces, the bricks of the brick lining were given the opportunity to in the event of thermal stresses to one another while executing a slight rotary movement slide. This relative sliding of the abutting stone edges can damage the masonry and in particular be turned away from the induction coil, since those with the mentioned Rotary movement of the stones associated slight increase in the furnace outside diameter without Damage can be absorbed.

According to an advantageous embodiment of the invention, the size of the acute angle is determined the abutting edge surfaces with the radius of the vessel graphically through the direction a straight line drawn between two points, the first point being determined by the Intersection of a connecting line between the one lateral inner edge of the stone and the center point the circular brickwork with the circumference of a circle around this center, the radius of which is the has half the amount of the inner radius of the brickwork, and with the second point through the other lateral Inside edge of the stone is set.

The invention is explained below using an exemplary embodiment with reference to the drawing described in more detail. In this show

F i g. I a plan view of an induction furnace according to the state of the art,

FIG. 2 shows a section through a furnace according to the prior art according to FIG. 1.

F i g. 3 is a plan view of a furnace provided according to the invention;

Fig.4 shows the manner in which the angle of inclination the abutting stone edges within the furnace is determined and

FIG. 5 shows a section of the one shown in FIG Arrangement, whereby the forces acting in Jen abutting edge surfaces of the stones according to the invention occur as a result of thermal expansion.

As best shown in Figs. I and 2, the furnace shown has a refractory Stones 12 existing cylindrical wall 10 and a bottom, which consists of a plate 14 of refractory Material is made. The wall 10 following an induction coil 16 is provided, which with a AC power source not shown can be connected. The spool 16 is of a support structure surrounded, which in the illustrated embodiment comprises a cylindrical jacket 18, which on un floor plate 20 rests. A layer 15 is located between the stones 12 and the induction coil 16 rammed mortar. Like F i g. I shows, the stones 12 have a curved shape and abut one another Edge surfaces which touch one another along the radius of the circular wall 10. As a result, the mutually touching surfaces lie on lines that go through the center point of the circular structure. In a jar-like arrangement, the leads within the melting vessel generated heat to thermal expansion forces in the stones 12. Since the end edges of the stones in the Run essentially radially, the Tangentialöder circumferential forces, which ah the contact surfaces are generated between adjacent stones, too an increase in the diameter of the entire circular

shaped structure, whereby the Stampimasse 15 against the coil 16 is printed. As already explained, this can lead to permanent deformation of the surrounding area Induction coil 16, damage to the ramming mass and possibly cracks in the Lead furnace wall, which results in an outflow of metal.

A plan view of a melting vessel which is lined up according to the invention is shown in FIG. 3 shown. The in F i g. 3 and Fig. 1 agree with the exception that in the construction according to the invention according to FIG. 3, the abutting edge surfaces of the stones 22 now run along the lines 23 which form an acute angle with the radius of the circular vessel. This is best seen in FIGS. 4 and 5. The radius of the melting vessel is shown by line 24. It should be noted that the laterally adjoining edge surfaces ο 23 inclined in the same direction acute angle with the radius 24 form the vessel. When the stones expand as a result of the heat, each refractory stone experiences thermal expansion, which causes tangential forces F ₁ (Fig. 5) and stresses between the stones.The tangential force F, can be divided into two components, F and F _p . The force F ₉ is perpendicular to the edge surface 23, while the force F _{r runs} in the plane of contact between two adjacent stones. Whenever the force F, reaches a value in which the force F _{r is} greater than the frictional force acting in the contact plane between the stones, a sliding movement occurs between the stones and each stone is made to stretch in a clockwise direction. that the top and bottom edges of the stone are caused to move a very small distance towards the dashed line location 26 in FIG. 5 to move, in which this process is shown enlarged for the purpose of better explanation. This rotary movement serves to reduce a diameter-wise or circumferential enlargement of the original circular brickwork under the influence of thermal expansion.

It can be seen from Fig. 5 that conventional stones have corners which are defined by points abc d . Under these circumstances, the forces F _n and F _r do not occur, since the thermal expansion force F, is perpendicular to a line bc which runs on the radius of the circular vessel. The stone shape according to the invention is defined by the corners A, B, C, D. It should be underlined that the abutting edges of the stones, which are defined by the lines AD and fl-CT, do not run on radii 24 of the circular furnace.

The angular relationship of the lines AD and BC ίο is determined by first drawing a circle, which in FIG. 4 is provided with the reference number 30.The radius of this circle must be greater than 0 and smaller than the inner radius R ₀ of the brickwork formed by the stones 22, is preferably the radius of the circle 30 is half of the inner radius R ₀ , which means that the Can express the size of the radius of the circle 30 as RJl. To determine the size and shape of the stones, assuming that 20 stones are to be used to form the furnace wall, circle 30 is divided into 20 equal circular arc sections. ilt, 4 of which in FIG. 4 and are denoted by the reference numerals 32/1, 323, 32C and 32D. By drawing radii through the points 34 at the ends of each equally sized arcuate section 32A, 325, etc., the inner edges CD of each arcuate curved stone can be found. Then the angle α of the edges 23 with the radius 24 is determined, for which purpose a line is drawn from the inner in radial end D, for example an edge surface of a stone, to a point 34 on the circle 30. This point 34 is determined by the intersection of a connecting line, which coincides with a radius 24, between the one lateral υ inner edge (T of the stone 22 and the center 28 of the circular brick lining with the circumference of the circle 30 around this center. The point Dist through the defined other lateral inner edge of the stone 22. As already explained, the radius d = s circle 30 need not be equal to half the radius of the inner circumference of the furnace wall, although this is encouraged. If the radius of the circle 30 is increased, the angle o thus also increases. If, on the other hand, the radius of the circle 30 is reduced, see 4, the angle 0 is correspondingly reduced.

For this purpose 2 sheets of drawings

Claims (2)

Patent claims: 1. Refractory lining of a krcisiormigen A vessel for molten metal, in particular the lining of an inductively heated furnace Stacked, arched, arched stones, characterized in that the laterally abutting edge surfaces (23) of the stones (22) such in the same direction inclined acute angle (o) with the radius (24) of the vessel, that with thermal expansion of the Brick lining the edge surfaces of the stones slide against each other. 2. Refractory lining according to claim 1, characterized in that the size of the, _ angle (o) graphically determined by the direction of a straight line drawn between two points (D, 34) , wherein