Continuous furnace hearth

Abstract

FIELD: metallurgy.SUBSTANCE: invention relates to the design of heating furnaces. The continuous furnace hearth comprises a foundation with concrete blocks installed on it. Concrete blocks are made in the shape of a parallelepiped with a groove cut along the entire length of the block, forming an elongated groove along the hearth. On one of the mating surfaces of each concrete block, a connecting element in the form of an inverted letter U is made, and on the opposite mating surface, a corresponding groove is made, ensuring the connection of the concrete blocks to each other in a protrusion-depression manner. Ceramic guides made in the shape of a parallelepiped are installed in the groove. The upper working surface of the ceramic guide is chamfered across the width, and the lower surface is rounded along the entire length, with the ceramic guides located in the groove of the concrete blocks in two rows in a staggered pattern relative to each other, overlapping the lowered plane formed by the chamfers to form a flat surface without joints. The groove in concrete blocks is made with a depth of 1 / 3 to 1 / 2 the height of the concrete block, with a width of 1 / 2 to 2 / 3 the width of the concrete block along the entire length. The chamfers on the ceramic guides are made with a size from 1 / 6 to 1 / 4 of the length of the ceramic guide and from 1 / 20 to 1 / 10 of the height of the ceramic guide. The blocks are made of concrete comprising, %: Al2O3 not less than 62, CaO not more than 3, Fe2O3 not more than 1, and have an open porosity of not more than 20%, and ceramic guides comprise, %: Al2O3 not less than 85, Fe2O3 not more than 1.EFFECT: increasing the reliability of the design of the continuous furnace hearth by preventing jamming of workpieces in the furnace and reducing the risk of extreme loads on the furnace pushing system, hearth and roof.2 cl, 5 dwg

Description

[0001] The invention relates to the field of metallurgy, in particular to the design of heating furnaces.

[0002] A continuous pusher furnace is known from the prior art [RU 198174, IPC F27D 3 / 12, F27B 9 / 24, published 06 / 22 / 2020, Bulletin No. 18], comprising a hearth made of refractory brickwork, on the surface of which flexible metal elements lie. The flexible elements are made in the form of strips or rods. One ends of the flexible metal elements are fixed at point A. A load is freely suspended from a roller to the other ends of the flexible metal elements 2 after they have been bent around them. A pusher is installed at the inlet of the continuous pusher furnace with end feed. A slide, a receiving roller table, and a damping device are installed at the outlet of the continuous pusher furnace with end discharge. A chute is installed at the outlet of the continuous pusher furnace with side discharge.

[0003] Also from the source "Construction of Industrial Furnaces." 5th edition, revised and enlarged. Ed. by I.A. Shishkov. Moscow, Stroyizdat, 1978 (see p. 112), it is known that fireclay brick is the most common material used for lining heating furnaces. Furnace hearths are laid out of magnesite or talc brick, as they are the most resistant to scale and slag. Furthermore, there is positive experience with continuous furnaces in which the hearth is laid on a foundation made of concrete blocks with forsterite filler.

[0004] The main drawback of such hearth designs is that during furnace operation, particularly when pushing and / or moving heat-treated workpieces, the workpieces become stuck at the joints of the concrete blocks, leading to deformation and displacement of the concrete blocks and metal guides. These circumstances lead to workpieces becoming stuck in the furnace, destruction of the furnace walls and ceiling, and the furnace being shut down for premature repairs and production downtime.

[0005] This design of the continuous furnace hearth was chosen by the authors as a prototype.

[0006] The problem that the claimed invention is aimed at solving is to create a design for the hearth of a continuous furnace that prevents the occurrence of extreme loads on the furnace pushing system, hearth and roof, leading to their destruction.

[0007] The technical result of the claimed invention consists in increasing the reliability of the design of the continuous furnace hearth by preventing jamming of workpieces in the furnace and reducing the risk of extreme loads on the furnace pushing system, hearth and roof.

[0008] In addition, this solution ensures stable and uninterrupted operation of the furnace, and ease of installation of ceramic guides by reducing their weight and dimensions.

[0009] The stated problem is solved, and the technical result is achieved by the fact that the bottom of the continuous furnace contains a base with concrete blocks installed thereon, made in the form of a parallelepiped with a groove cut along the entire length of the block, forming an elongated groove along the hearth, while on one of the mating surfaces of each concrete block a connecting element in the form of an inverted letter U is made, and on the opposite mating surface a corresponding groove is made, ensuring the connection of the concrete blocks between themselves according to the "protrusion-depression" type, while ceramic guides made in the form of a parallelepiped are installed in the groove, on the upper working surface of the ceramic guide chamfers are made along the width, and on the lower surface a rounding is made along the entire length, wherein the ceramic guides are located in the groove of the concrete blocks in two rows in a checkerboard pattern relative to one another, with an overlap of the lowered plane formed by the chamfers,forming a smooth surface without joints,

[0010] The groove in the concrete blocks is made with a depth of 1 / 3to 1 / 2 the height of the concrete block, with a width of 1 / 2to 2 / 3 the width of the concrete block along the entire length.

[0011] The chamfers on the ceramic guides are made in sizes from 1 / 6to 1 / 4along the length of the ceramic guide and from 1 / 20 to 1 / 10 by height.

[0012] The connecting element and the mating groove have a semi-cylindrical cross-section.

[0013] The essence of the claimed invention is explained by graphic material.

[0014] FIG. 1 - Under the continuous furnace;

[0015] FIG. 2 - Concrete block (main view);

[0016] FIG. 3 - Concrete block (Fig. 2, top view);

[0017] FIG. 4 - Guide (main view);

[0018] FIG. 5 - Guide (Fig. 4, left view).

[0019] The base of the continuous furnace (FIG. 1) contains a base 3 with concrete blocks 1 installed on it, which in cross-section represent a structure that is a parallelepiped with a cut groove 1.1 along the entire length of the block.

[0020] On one of the mating surfaces (not indicated on the drawings) of each concrete block 1 there is a connecting element 1.2, and on the opposite mating surface a mating groove 1.3 is made. The implementation of connecting elements 1.2 and mating grooves 1.3 on the mating surfaces of concrete blocks 1 makes it possible to obtain a connection of the "protrusion-depression" type.

[0021] Connecting elements 1.2 and mating grooves 1.3 are preferably made in the form of a semi-cylindrical section in the shape of an inverted letter P.

[0022] Concrete block 1 is made with height H, width A, length L, groove 1.1 is made with depth h, width A1, length L.

[0023] When assembled together, concrete blocks 1 form an elongated longitudinal groove along the entire hearth. Ceramic parallelepiped guides 2 are placed in this groove.

[0024] On the upper working surface of the ceramic guide 2, chamfers 2.1 are made across the width, and on the lower surface, rounding 2.2 is made along the entire length.

[0025] Ceramic guide 2 is made with height H1, length L1, width A2, chamfers with height h1, length L2 and width A2.

[0026] Ceramic guides 2 are installed in the groove formed by concrete blocks 1, in two rows with a staggered arrangement relative to each other, covering the lowered surface formed by chamfers 2.1, forming a smooth surface without joints for the placement of workpieces.

[0027] Example of the implementation of the claimed invention

[0028] The base of a continuous furnace comprises a base 3 with concrete blocks 1 installed on it. The cross-section of the blocks is a parallelepiped with a groove 1.1 cut along the entire length of the block. Concrete blocks 1 are manufactured with the following parameters:

[0029] - length L equal to 295 mm, height H equal to 440 mm, width A equal to 460 mm,

[0030] - groove 1.1 is made with a depth of h 160 mm (corresponds to 1 / 3 of the block height), the width of the groove A1 equal to 220 mm (corresponds to 1 / 2 block width) for a block length L equal to 295 mm, the connecting element 1.2 and the mating groove 1.3 are made in the form of a semi-cylindrical section in the shape of an inverted letter P with a radius of 15 mm.

[0031] Ceramic guides 2 are made with the following parameters:

[0032] - height H1 equal to 200 mm, length L1 equal to 500 mm, width A2 equal to 105 mm;

[0033] - chamfers 2.1 height h1 equal to 10 mm (corresponds to 1 / 20height of the guide), length L2 equal to 100 mm (corresponds to 1 / 5 of the guide length) to the width A2 equal to 105 mm;

[0034] - rounding 2.2 is made with a radius of 20 mm.

[0035] When assembled together, concrete blocks 1 form an elongated longitudinal groove along the entire hearth. Ceramic guides 2 are installed in this groove, in two staggered rows, overlapping the lowered surface formed by chamfers 2.1, creating a smooth, seamless surface for the workpieces, thereby reducing the risk of workpieces getting stuck in the kiln during movement.

[0036] Execution of concrete block 1 with groove 1.1 of depth h less than 1 / 3 of the height H reduces the height H1 of the guide 2 and, as a consequence, its strength. With a depth h of the groove 1.1 more 1 / 2 of the height H of a concrete block reduces its strength.

[0037] Execution of concrete block 1 with a groove of width A1 less 1 / 2 of width A reduces the width A2 of the ceramic guide 2 and, as a consequence, its strength. With a groove width A1 greater 2 / 3 of the width A there is a decrease in the strength of the concrete block 1.

[0038] Execution on ceramic guides 2 chamfers 2.1 size L2 less 1 / 6 along the length L1 does not give the effect of smooth sliding of the workpiece, and with the length L2 more 1 / 4L1- not effective; chamfer 2.1 with size h1 less 1 / 20 in terms of height H1 is not effective, but at h1 it is more 1 / 10 size H1 - does not provide the effect of smooth sliding of the workpiece.

[0039] Blocks 1 can be made of concrete containing in the chemical composition Al2O3 not less than 62%, CaO not more than 3%, Fe2O3 not more than 1%, while the open porosity is not more than 20%.

[0040] Ceramic guides may contain at least 85% Al2O3 and no more than 1% Fe2O3 in their chemical composition, with a compressive strength of at least 65 MPa and a maximum service temperature of 1650°C. Blocks and guides undergo high-temperature kiln treatment at a temperature of at least 1400°C. Using these products in the hearth design of a continuous furnace with a high Al2O3 content will achieve the following performance indicators:

[0041] - high compressive, tensile and bending strength;

[0042] - resistance to deformation and cracking;

[0043] - chemical resistance;

[0044] - low weight compared to heat-resistant steel grills, high quality and heating efficiency.

[0045] The claimed design of the continuous furnace hearth, consisting of concrete blocks and ceramic guides, has a number of advantages over the prototype, namely:

[0046] - eliminates the possibility of workpieces getting stuck in the furnace working space when moving;

[0047] - guides made of high-strength concrete have significantly smaller dimensions and weight per unit of product, do not require disassembly and assembly of the furnace arch and the use of an overhead crane during (de)installation during repair work;

[0048] - the furnace hearth lining consists of a much smaller number of assembly units;

[0049] - the modular design allows for the replacement of individual elements without completely disassembling the furnace hearth and removing all guides;

[0050] - reduction of repair complexity and, as a result, a significant reduction in the time required for repair work and forced equipment downtime.

Claims

1. A continuous furnace hearth comprising a base with concrete blocks installed thereon, characterized in that the concrete blocks are made in the shape of a parallelepiped with a groove cut along the entire length of the block, forming an elongated groove along the hearth, wherein on one of the mating surfaces of each concrete block a connecting element in the shape of an inverted letter U is made, and on the opposite mating surface a corresponding groove is made, ensuring the connection of the concrete blocks to each other according to the protrusion-depression type, wherein ceramic guides made in the shape of a parallelepiped are installed in the groove, on the upper working surface of the ceramic guide chamfers are made along the width, and on the lower surface a rounding is made along the entire length, wherein the ceramic guides are located in the groove of the concrete blocks in two rows in a checkerboard pattern relative to one another, with an overlap of the lowered plane formed by the chamfers with the formation of a flat surface without joints,the groove in the concrete blocks is made with a depth of 1 / 3 to 1 / 2 the height of the concrete block, with a width of 1 / 2 to 2 / 3 the width of the concrete block along the entire length, the chamfers on the ceramic guides are made with a size of 1 / 6 to 1 / 4 the length of the ceramic guide and from 1 / 20 to 1 / 10 the height of the ceramic guide, while the blocks are made of concrete containing, %: Al2O3 not less than 62, CaO not more than 3, Fe2O3 not more than 1, and have an open porosity of not more than 20%, and the ceramic guides contain, %: Al2O3 not less than 85, Fe2O3 not more than 1., 2. The base of a continuous furnace according to paragraph 1, characterized in that the connecting element and the mating groove have a semi-cylindrical cross-section.

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