RU2251648C1 - Furnace arch - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: furnace arch comprises housing having ring brickwork courses laid with the use of a fireclay mortar, with ring courses made of blocks of fireclay bricks provided with openings, metallic plates with openings secured to the housing, pins, and lining of the central section. Each fireclay brick is provided with a flat groove and opening on one side and opening on the opposite side adjacent to the flat groove and opening in the adjacent brick in the ring course. The blocks of each ring course are interposed between two metallic plates. The end fire bricks of the blocks are interconnected through pins set in the openings of the plates. The openings without pins in the fire bricks are filled with a fireproof solution. The size of the flat groove corresponds to the size of the plate. The openings in the fireproof brick and plate are axially aligned.

EFFECT: enhanced reliability of the arch.

4 cl, 1 ex

Description

The invention relates to metallurgy and can be used in the production of metals in arc melting furnaces.

Known for the arch of an electric arc furnace, including refractory masonry from vaulted products and the seams between them, filled with refractory mortar. Moreover, the thickness of the joints between the bricks is 2-3 mm (Kaybicheva MN “Lining of electric furnaces”, M., 1975, p. 36).

The disadvantage of this design of the arch is the low resistance of the lining, because thin seam does not sufficiently compensate for the thermal expansion of bricks during operation. There is a mechanical chipping of pieces of brick.

Similar disadvantages have the well-known arch of the industrial furnace, including refractory masonry of the periphery of the arched products and the joints between them, filled with refractory mortar, 0.15-0.25 thickness of the arched products thickness (Aut. St. No. 832289, F 27 D 1/02, 1979).

The proposal to use a combined masonry with increased thickness of the seams at the periphery and a twofold decrease in the thickness in the central part of the roof also does not compensate for internal temperature stresses in the refractory (Aut. St. No. 991123, F 27 D 1/02, 1983).

A refractory stone is known for lining metallurgical units, in which, in order to increase the thermal stability of the lining of metallurgical units, increase the tightness of masonry and reduce heat loss to the environment, recesses are made on the lateral faces of the auxiliary section, and protrusions repeating the shape of the recesses are made on opposite sides. The conjugation of adjacent refractories occurs when the lining is closed into a continuous geometric structure, the locking part of which prevents the loss of individual blocks with the possible destruction of the suspension system (Russian Patent No. 2082928, 6 F 27 D 1/04, 1997).

The disadvantages of such a refractory stone, if used in the arches of furnaces with high heat load, requiring the use of forced, for example, water, cooling of the elements of its structure or the entire surface of the arch, are its low reliability and low durability of the lining. Performed on adjacent lateral faces of the refractory stone along the entire length of the surfaces of the faces and the notches mating with each other, under conditions of strong temperature loads, they will play the role of centers of concentration of internal stresses at the boundary between the main and auxiliary parts of the stone. This will lead to chipping of the main part, especially since the resulting destructive stresses will be amplified by a bending moment on the main part of the stone relative to the recess, resulting from the wedging action of the melting products falling into the gap between the surfaces of the working parts of neighboring stones and the inability to move the auxiliary parts of neighboring stones, which will be pinched under the compressive force of thermal stresses.

Known water-cooled arch containing a metal water-cooled housing with a lining on the side of the working space of the furnace, in which, in order to increase its durability, the metal housing is equipped with a metal partition with a bottom located along its entire perimeter and made continuous with a gap from the bottom equal to 0.003-0.005 the diameter of the arch, and in the basement part of the arch are openings around the entire circumference of the bottom for supplying water to the gap. Two pipes are installed between the upper wall of the casing and the partition one against the other, with openings in the side surfaces, and pipes are attached to the middle of each pipe, one of which is connected with a gap in the center of the partition, the other is connected to the side surface of the casing, the ribs of which performing the role of fixing the lining, protrude through the lower surface of the arch and form cells for applying the lining - refractory coating (Ed. St. No. 872930, F 27 D 1/02, 1981).

The disadvantage of this device, when used in furnaces with a large thermal load, is the low resistance of the lining. This is due to the fact that, as the holes are removed from the cooler inlet, due to an increase in resistance to movement, the flow rate decreases and the number of the cooler collector flowing out of the holes decreases. And this leads to uneven intensity of heat removal from the heat-absorbing surface of the arch, which sharply reduces the physicomechanical properties of the metal of which this part of the arch is made, the arch is deformed, and the refractory coating undergoes cracking and destruction.

The closest in technical essence and the achieved result is the arch of the arc furnace containing a vault ring, masonry of the peripheral part, a central ring mounted on the vault and central rings of the hanging beams, fastened with plates and pins with bricks, and support beams rigidly connected to the central ring in which, in order to reduce stresses in the masonry of the arch and increase its durability, the arch is equipped with springs, on which support beams are mounted, installed in guides on the lower movable cross-arms, connected with the upper traverses mounted on the shoulders of the guides, which are rigidly fixed on the arch ring (Aut. St. No. 728457, F 27 D 1/02, 1986).

The disadvantage of this device, when used in furnaces with a large thermal load, is the low resistance of the lining. This is due to the fact that at high heat load the proposed partial unloading of the arch, leading to a certain decrease in thermal stresses, will have a positive effect during the heating of the lining and in the initial period when the wear of the lining is determined by chips of refractories. With a greater thermal load, when predominant wear of refractory materials by fusion is observed, the organization of forced heat removal is required, as described in the description of the invention with respect to the central part of the arch, and it is also necessary to take measures to ensure the solidity and mechanical strength of the lining, its reliable fixation on the heat-removing surface of the arch.

The objective of the invention is to increase the durability of the arch.

The technical result from the use of the invention is to increase the durability of the arch due to the possibility of operating the lining to a smaller residual thickness.

The essence of the invention lies in the fact that in the arch of the arc furnace, including a housing with annular rows of masonry on a refractory mortar, each row of which is made in the form of blocks of refractory bricks with holes, metal plates with holes fixedly mounted on the housing, pins and lining of the central parts, according to the invention, each refractory brick is made with a flat groove and a hole on one side and a hole on the opposite side adjacent to a flat groove and a hole adjacent to the ring next to the brick row, the blocks of each annular row are located between two metal plates, the extreme refractory bricks of the blocks are connected using pins installed in the holes of the plates, the holes without pins in the refractory bricks are filled with refractory mortar, the size of the flat groove corresponding to the size of the plate, and the holes in the refractory brick and plate are aligned.

The execution on each refractory brick of a flat groove on one side is necessary to cover the metal plate from the damaging effects of high temperature and the furnace environment, reduce the seam between the surfaces of the refractories, faster and better install and fix the brick relative to the plate and, accordingly, the brick in the block and block on surface of the arch.

The execution on each refractory brick on the side of the flat groove of the hole is necessary to install a rod that simultaneously enters the hole in the plate and into the hole of a brick adjacent to the ring row, which ensures installation and fixation to the surface of the brick arch and the block as a whole. If this brick does not require the installation of a plate when assembling the block, then the hole is necessary for the formation, together with the hole of the adjacent brick in the annular row, of a space in which a peculiar mechanical connection will form with changing properties depending on the length of time of its formation and on the intensity of exposure on it the temperature of the furnace environment.

A hole is made on each refractory brick on the side adjacent to the flat groove and the hole of a brick adjacent to the ring row in the ring row, it is necessary to install a rod that simultaneously enters the hole in the plate and into the hole of the brick adjacent to the ring row, which ensures installation and fixation to the surface of the roof brick and block as a whole. If this brick does not require the installation of a plate when assembling the block, then the hole is necessary for the formation, together with the flat groove and the hole of the adjacent brick in the annular row, of a space in which a peculiar mechanical connection will form with changing properties depending on the length of time of its formation and from the intensity of exposure to the temperature of the furnace environment.

The location of the blocks of each annular row between two metal plates is necessary to create mechanical strength and rigidity of the block, its reliable fastening on the surface of the arch.

The connection of the extreme refractory bricks of the blocks with the help of pins installed in the holes of the plates is necessary for reliable connection and fastening of the blocks together in an annular row of masonry and on the surface of the arch, creating the necessary mechanical strength and stiffness of the annular row of masonry.

Filling holes without pins in the refractory bricks with a refractory mortar is necessary so that the refractory mortar in the curing process forms in the space formed by the holes a kind of mechanical connection between the refractory bricks - a refractory rod, which, depending on the length of time of its formation and on the intensity of exposure to it the temperature of the furnace environment will have the necessary, during a certain period of operation, properties, which, in turn, will determine the necessary for operating a series of annular clutch properties and durability of masonry as a whole.

The execution of the size of a flat groove corresponding to the size of the plate is necessary for quick and accurate location and fixation in a given position of the brick in the block and the block on the surface of the arch.

Coaxial arrangement of the holes in the refractory brick and in the plate is necessary for high-quality and quick assembly of refractory bricks into blocks and blocks into ring masonry.

The execution of each annular row of masonry in the form of blocks of refractory bricks is carried out in order to form an arrangement structure in which the connection of two adjacent refractory bricks alternates with a rigid mechanical connection - a metal rod - with the connection of one or two refractory bricks installed next to them with a connection with variable properties depending on the intensity of the temperature field, i.e. field temperature and its duration.

The combination of these and justified distinguishing features of the proposed device will allow you to get the effect of increasing the durability of the arch due to the possibility of using the lining to a lesser residual thickness due to the formation of a certain structure of blocks of refractory bricks and ring rows of masonry from these blocks, in which the connection of two adjacent bricks with a rigid mechanical connection is alternated - with a metal rod - with the connection of one or two refractory bricks installed with them adjacent to the change yuschimisya properties, the latter being dependent on the length of time of formation of the connection and the intensity of exposure to the furnace temperature environment.

The device “Arch arc furnace” is known (Aut. St. No. 691667, F 27 D, 1979), in which there is a feature similar to the claimed one, namely, in the arch of the furnace, part of the refractory bricks is made with holes into which the pins are inserted, connecting the bricks into circular and radial rows forming a framework, inside of which there are zones made of bricks not connected by pins.

However, in the known device, this feature works differently. The pins are used to connect all the bricks in the ring rows to each other or to connect three to five bricks in the ring rows with a periodically repeating number of bricks not connected by pins, while three to five of these bricks from adjacent ring rows form radial rows on the roof of the furnace. It must be emphasized that the bricks in the radial rows are not interconnected by pins, but are connected only in the annular rows. In this way, a framework of circular and radial rows is created, inside of which there are zones made of bricks not connected by pins. Only ring rows will have sufficient structural strength in such a design, which determines not initial stiffness and low durability of the arch.

In the inventive arch of the furnace, each refractory brick is made with a flat groove and a hole on one side and a hole on the opposite side adjacent to a flat groove and a hole of a brick adjacent to the ring row. The pins not only connect the extreme bricks in the adjacent blocks of each annular row, but at the same time they are installed in the holes of the metal plates fixedly located on the body of the arch. This ensures both the connection between the blocks and the fixation of the blocks to the metal surface of the arch. In addition, openings without pins in the refractory bricks are filled with a refractory mortar, which plays the role of a certain connection with the changing properties. As the outer working surface of the refractory bricks deteriorates, the temperature of the refractory solution located in the space of the formed bond will increase, which ultimately leads to its sintering and the acquisition of new properties that did not exist before, including the mechanical strength of the sintered ceramic structure, which is accompanied by volumetric expansion. The resulting volumetric stresses will be directed opposite to the thermal stresses in the refractory bricks and will partially compensate for their effect.

A detailed analysis and analysis of a similar feature shows that the proposed device achieves a new effect that could not be achieved in the known device, which indicates the compliance of the claimed object with the criterion of "inventive step".

The invention is illustrated by drawings, where in Fig.1 shows the arch of the furnace in a section, in Fig.2 - node A in Fig.1, Fig.3 is a section along BB in Fig.2, Fig.4 is a refractory brick.

The device comprises a metal casing 1, on the inner surface of which an annular masonry 2 is made, each row of which consists of adjacent refractory blocks, assembled on refractory mortar 3 of refractory bricks 4. Each refractory brick 4 has a flat groove 5 and a hole 6 on one the side adjacent to the adjacent refractory brick in the annular row, and the hole 7 on the opposite side. The extreme refractory bricks of the 4 blocks are connected to the plates 8 fixedly mounted on the housing 1 with holes 9 using the pins 10 installed in their holes, respectively holes 6 and 7 of the refractory bricks 4 and holes 9 of the plates 8. In the hole blocks 6 and 7 of the adjacent refractory bricks 4, in which the pins 10 are not located, are filled with refractory mortar 3. In each refractory brick 4, the size of the flat groove 5 corresponds to the size of the plate 8, and the holes 6 and 7 have the same diameter. The diameter of the hole 9 of the plate 8 is slightly larger than the diameter of the holes 6 and 7 of the refractory brick 4. The holes 6, 7 of the refractory brick 4 and the hole 9 of the plate 8 are aligned.

The device operates as follows. The vault made at the stand and dried is installed on the furnace and connected to the heat supply and exhaust lines - water (not shown). During the initial period of operation of the arch, the resulting volumetric expansion of refractories and thermal stresses in them are partially compensated by deformation of the masonry, and linear deformation of the lining of the arch is prevented by metal plates 8, which are fixedly mounted on the housing 1 on one side and have openings 9 on the other side in which metal pins 10 included in the holes 6 and 7 of the refractory bricks 4. Such a suspension and rigid fixation of the refractory bricks 4 in the blocks ensures a reliable fit of the refractory bricks 4 to the surface of the vault 1, which contributes to the organization of heat transfer from the surface of the bricks in contact with the working space of the furnace to the water-cooled surface of the body 1 of the vault without losses associated with the possible formation of voids, i.e. without heat resistance. As the outer working surface of the refractory bricks 4 deteriorates, the temperature of the refractory solution located in the holes 6 and 7 of the adjacent refractory bricks increases, which ultimately leads to its sintering and the acquisition of new, non-existent properties, including sintered mechanical strength ceramic structure, the formation of which is accompanied by volume expansion. The resulting volumetric stresses will be directed opposite to the thermal stresses in the refractory bricks and will compensate for their effect. The result is an increase in the resistance of refractory bricks 4. The strength of the sintered ceramic structure is sufficient to withstand the load from the weight of the refractory blocks at a time when a part of the metal plates 8 together with the metal pins 10 installed in their holes 9 are destroyed under the influence of temperature and atmosphere of the furnace working space. This leads to a decrease in the reliable residual operational thickness of the refractory bricks and can contribute to the formation of a skull layer on their working surface, which will increase their service life.

An example of a specific implementation of the device.

According to the TV project 2519.00.00.00. SB “Lining of the roof of the furnace RNB-5”, the device contains a metal casing, on the inner surface of which an annular masonry of 5 rows was made, each row of which consists of adjacent refractory blocks that were assembled on a refractory chromite-periclase solution of refractory bricks of the grades ХПТУ-1А, ХПТУ-8А (113А), ХПТУ-9А, ХПТУ-10А. Each refractory brick has a flat groove of 75 × 64 mm on one side. A flat groove begins at the end of the brick adjacent to the surface of the body of the arch, and is located symmetrically to the vertical axis of this side of the brick. Similarly axisymmetrically on this surface of the brick, a blind hole with a diameter of 18 mm at the entrance and 17 mm at the bottom is made at a distance of 45 mm from the end of the brick. The hole depth is 15 mm and coaxially on the opposite side of the brick a blind hole is also made with a depth of 20 mm with inlet diameters of 18 mm and 17 mm at the bottom. The layout of the refractory bricks into blocks is made in such a way that two or three refractory bricks are predominantly typed into the refractory block between the metal plates. The holes of the extreme refractory bricks of the blocks are connected using metal rods through holes in the plates welded from the inside to the metal structure of the body of the arch with holes in the adjacent refractory bricks. In the blocks, the openings in adjacent refractory bricks in which the pins are not located are filled with a refractory chromite-periclase solution. In each refractory brick, the size of the flat groove corresponds to the size of the plate, and the diameter of the through hole in the metal plate is 17.5 mm, while the hole in the refractory brick and the hole in the plate are aligned.

The composition of the chromite-periclase solution on liquid glass per 1 cubic meter m .:

- chromite-periclase aggregate (ZHPU), class 7

(bulk density 2.0-2.2 g / cc) 2000 kg (1000 l)

- liquid glass (density 1.36-1.38 g / cc) 870 kg (640 l)

- sodium silicofluoride (bulk density 1.29 g / cc) 87 kg (67 l)

Chromitopericlase solution for arch set-up is prepared at the place of masonry in mortar mixers with rotating blades of any type. The aggregate loaded into the solution mixer is moistened with liquid glass as it mixes until a thick consistency solution is obtained.

The use of the new arch design on the RNB-5 furnace allowed us to reliably reduce the residual thickness of refractory bricks to 30-35 mm, which is approximately 1.5-2.0 times less than it was. This contributed to an increase in the service life of the vault by 15-20%.

The claimed technical solution is original, does not follow obviously from the existing level of technology and meets the requirements of "inventive step".

Thus, the claimed technical solution fully fulfills the task. The claimed technical solution is currently not known in the Russian Federation and abroad and meets the requirements of the criterion of "novelty."

The technical solution can be implemented industrially in mass production using well-known technical means, technologies and materials and meets the requirements of the criterion of “industrial applicability”.

Claims (1)

The furnace vault, comprising a body with annular rows of masonry on a refractory mortar, each row of which is made in the form of blocks of refractory bricks with holes, metal plates with holes fixedly mounted on the body, pins and lining of the central part, characterized in that each refractory brick is made with a flat groove and a hole on one side and a hole on the opposite side adjacent to a flat groove and a hole of a brick adjacent to the ring row, the blocks of each ring row are located between two With metal plates, the extreme refractory bricks of the blocks are connected using pins installed in the holes of the plates, the holes without pins in the refractory bricks are filled with refractory mortar, the size of the flat groove corresponding to the size of the plate, and the holes in the refractory brick and in the plate are aligned.

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