US3828509A

US3828509A - Refractory block for lining firing and melting chambers

Info

Publication number: US3828509A
Application number: US00319703A
Authority: US
Inventors: P Ottmar; H Stein
Original assignee: Didier Werke AG
Current assignee: Didier Werke AG
Priority date: 1972-01-03
Filing date: 1972-12-29
Publication date: 1974-08-13
Anticipated expiration: 1991-08-13
Also published as: CA1000052A; FR2174509A5; AT330060B; ATA973A; JPS4874404A; BE793509A; JPS5147B2; DE2200081A1; GB1386898A; DE2200081C3; SE384407B; DE2200081B2; CH559344A5

Abstract

A refractory block for lining the firing and melting chambers of metallurgical furnaces or melting equipment includes a metal support in the form of a lattice consisting of longitudinal and transverse bars forming openings. In each opening is positioned at least one brick. Each brick is provided adjacent one end thereof on one longitudinal side thereof with a groove for the reception of the bars extending in one direction of the lattice, and on adjoining longitudinal sides with recessed portions for the reception of the bars extending in the other direction.

Description

United states Patent 1191 Ottmar et al.

1451 Aug. 13, 1974 REFRACTORY BLOCK FOR LINING FIRING AND MELTING CHAMBERS Inventors: Paul Ottmar,

Wiesbaden-Erbenheim', Hermann Stein, Bad Durkheim, both of Germany Assignee:

Didier-Werke A.G., Wiesbaden,

Germany [22] Filed:

Jan. 3, 1972 US. Cl...,

Int. Cl.

Dec. 29, 1972 Appl. No.1 319,703

Foreign Application Priority Data Germany 2200081 F276 1/04 Field of Search 52/575, 596, 598, 605,

110/1 A, l B, 99 R; 432/247 References Cited UNITED STATES PATENTS Griffiths 1 10/] B 1,529,183 3/1925 l-lowren 110/1 B 2,075,602 3/1937 Davey 52/598 X 2,125,192 7/1938 Morlock 52/575 X 3,148,482 9/1964 Neale 52/388 X 3,252,261 5/1966 Rigby 52/605 X I Primary Examiner-Price C. Faw, Jr.

Attorney, Agent, or Firm-Wenderoth, Lind & Ponack 57 ABSTRACT A refractory block for lining the firing and melting chambers of metallurgical furnaces or melting equipment includes a metal support in the form of a lattice consisting of longitudinal and transverse bars forming openings. In each opening is positioned at least one brick. Each brick is provided adjacent one end thereof on one longitudinal side thereof with a groove for the reception of the bars extending in one direction of the lattice, and on adjoining longitudinal sides with recessed portions for the reception of the bars extending in the other direction.

7 5 Claims, 4 Drawing Figures REFRACTORY BLOCK FOR LINING FIRING AND MELTING CHAMBERS BACKGROUND OF THE INVENTION The invention relates to refractory blocks of adhesively bonded bricks and a metal support, for lining the firing and melting chambers of metallurgical furnaces or melting equipment.

The employment of preassembled blocks for forming the refractory lining of metallurgical vessels can substantially reduce the time needed for the construction of the lining. This is particularly important in view of the fact that the basic refractory linings of electric arc furnaces, converters and ring-shaped induction furnaces are subjected to considerable wear and require renewal at frequent intervals.

The blocks may consist of rammed tar-bound dolomite reinforced with metal insertions provided with carrier elements. ln order to avoid the drawbacks inherent in rammed blocks regarding their density and strength it is necessary to produce blocks consisting of pressed, chemically bound, tar-bound or bumedbasic bricks. Furthermore, to ensure that blocks thus composed of individual bricks will form a coherent assembly, cement, adhesive bonding agents and metal supports are used.

The conditions governing the employment oflargesized blocks are substantially as follows:- The blocks should permit linings to be quickly erected and if possible they should be the only building element, as is the case for instance in electric arc furnaces. The expenditure in bricks, bonding agents and support means should be a minimum. Moreover, it is also desirable that in'the course of progressive and uneven wear during service the blocks shouldbe secure against collapse. Last but not least, an economic use of blocks also depends upon the worn lining being capable of being removed quickly without the creation of large amounts of loose rubble.

Hitherto blocks were composed of individual bricks cemented or adhesively bonded together and the blocks were provided with separate metal carriers fitted vertically on the face and back of each block to enable the block to be handled as a hanging load. However, these carriers are unsuitable for securing the brickwork in service or as aids when the lining is to be broken out. In the case of blocks of more ambitious construction comprising a metal baseplate and a number of iron hangers at the back as well as straps for holding the assembly together, better cohesion of the block during progressive wear may be achieved, but this is still not reliable.

The unexamined published specification of German Patent Application No. 1,433,548, published on Nov. 21, I968, describes a building unit for lining metallurgical furnaces in which the refractory bricks are bonded with a thermoplastic material, particularly tar. External support is additionally provided by metal bands and inside the block there is a metal reinforcement. However, this unit is not satisfactory, since the metal reinforcement will not continue to perform its purpose until the brickwork is broken out.

OBJECTS AND BRIEF DESCRIPTION OF THE INVENTION lt is the object of the present invention to improve the metal support and to dispose the same in the block in such a way that the cohesion of the block is assured from the time of its assembly, during transportation, erection and throughout the time of its service to the time the worn lining is finally broken out and removed.

For achieving this object, the present invention provides a support in the form of a lattice consisting of longitudinal and transverse bars which embrace the cold or outwardly facing ends of the bricks as near as possible to the outer sides of the block to allow the maximum amount of wear and loss of refractory material. Each of the bricks is provided adjacent the outer brick end, on one side face thereof, with a groove for the reception of the bars extending in one direction of the lattice and with a step or recessed portion at faces joining the one face for the reception of the bars of the lattice extending in the other direction. This arrangement provides a structurally simple and yet effective support system for the bricks in a block which with respect to its cohesion is extremely resistant to any stresses likely to arise during handling and erection. Furthermore, its cohesion is retained during service and the brickwork can wear away to the smallest possible remainder without any risk of a fracture. Worn brickwork can be removed after short periods of cooling of the metallurgical vessels, and time and work can be saved because the supporting structure remains undamaged and can be directly used for lifting out the remaining worn brickwork.

The lattices for the blocks are preferably prefabricated, the bricks being then inserted into the openings ,of the lattice mesh. In the majority of cases the lattices may be the steel mesh reincorcement conventionally used in building construction. Such reinforcements are cheap and they perform their purpose quite satisfactorily. However, if the blocks are exceptionally heavy and the lattice would have to consist of heavy gauge bars, it is preferred to assemble the lattice during the construction of the block, the bars of the lattice being inserted into the grooves and the recesses as the bricks are placed and then welded together at the crossover points. If necessary, the recesses which form openings in the outwardly facing ends of the block may be filled with a refractory grouting to cover the lattice bars.

The grooves and steps provided in the bricks of the block may be conveniently formed when the brick is molded or they may, of course, be formed by subsequent machining. The provision of an adhesive bond between the bricks ensures that the dimensions of the block will be preserved. Moreover, the adhesive bonding enables the creation of expansion joints and the response of the joints between the bricks to slag attack during service to be controlled in a desirable manner.

The blocks may be composed of square section bricks or of taper bricks or radial bricks. The bonding agent may with advantage be tar and pitch or a plastic bonding agent, particularly of the twocomponent type j in paste-like form.

Preferably each opening in the lattice is suitably dimensioned for the reception of two bricks. This enables the entire block to be fairly quickly assembled. The work is particularly simple if all the bricks are of the same shape and provided with the same kind of grooves and recesses. However, the insertion of a single brick or of any even number of bricks exceeding two in one opening is intended to be within the scope of the present invention.

The invention also includes the provision, on the lattice, of fittings for carrying the block, such as eyelets, lugs and the like. Their presence facilitates handling the block during transportation and when lining a furnace. Moreover, for improving the portability of a block as a hanging load a detachable carrier element may also be provided on the side of the block facing the fire, for instance in the form of a bracket held in position by dowels.

Preferably the bricks used for the construction of a block according to the invention may, near their cold or outwardly facing end, be provided on one longitudinal side with a transverse groove, whereas the two adjoining longitudinal sides may be recessed from the cold end of the brick to a point beyond the groove, thereby forming steps in the sides of the brick, the depth of the groove and of the recesses being equal to half the diameter of one of the lattice bars. Such bricks can be inserted singly or in even numbers into each opening of the prefabricated correspondingly dimensioned lattice. Moreover, they can also be used in the construction of blocks in which the lattice is assembled as the bricks are placed into position.

As already mentioned it is a major advantage of blocks according to the invention that the lattice and the bricks form a unit assembly in service and that this remains intact until the whole of the brickwork has been worn away excepting a small remainder which may then easily be removed. The lattice therefore constitutes a mesh which in sections of the size of the blocks covers the exterior of the brickwork throughout the life of the lining.

In this connection the invention further proposes that the brickwork should directly bear against the structure of the furnace or melting equipment in such manner that the columns of the structure support the back of the blocks at the vertical joints between neighboring blocks. This arrangement allows the costly outer shell or armor casing of the furnace or melting equipment to be unnecessary, whereby the overall cost of construction can be greatly reduced. A fracture of the brickwork by the pressure existing inside the furnace chamber need not be feared becasue the lattice embracing the outside of the brickwork can absorb the internal furnace pressure acting on the bricks, to the extent this pressure is not transmitted by the bricks directly to the furnace structure. The lattices of the blocks are therefore able, without any qualification, to undertake the functions of a shell or armor casing, namely to hold the brickwork together around the furnace chamber. Brickwork lacking an external shell is directly exposed to the cooling effect of the outside atmosphere so that special cooling means will generally not be needed. Moreover, worn brickwork can be broken out and fresh brickwork erected much more quickly and conveniently in the absence of an obstructing shell. If it is desired to insulate the outer face of the brickwork, then this can be quite easily done, for instance by pinning insulating mats on the back of the brickwork with the help of a pin driving gun.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be more particularly described with reference to the drawing:

FIG. 1 is a perspective view of a block during assembly, two bricks being insertable into each opening of the mesh,

FIG. 2 shows one of the bricks used for the assembly of a block, from the side and from above,

FIG. 3 is a perspective view of the cold or outwardly facing end of a brick and FIG. 4 is a top plan view of a block of bricks placed with its back against a furnace structure.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1 longitudinal bars 1 and transverse bars 2 are welded together at their crossover points to from a lattice 3 having rectangular openings 4. Each opening 4 is adapted to receive two bricks 5 of identical configuration, the cold or outwardly facing end 6 of each brick being provided on one longitudinal side with a transverse groove 7, whereas the faces of the two ad joining longitudinal sides are stepped inwardly at 8 to form a reduced section portion of the brick extending from the cold end to beyond the groove 7. The depth of the groove and of each step slightly exceeds half the diameter of a bar 1 or 2 of the lattice.

For assembling a block the lattice 3 is erected with its longitudinal bars 1 facing the bricks 5. The bricks are then inserted into the openings 4 of the lattice, starting from the bottom. The first brick 5 to be inserted into an opening 4 is inserted between the longitudinal bars 1 with its reduced end foremost and the smooth unbroken longitudinal face uppermost. The groove 7 is brought into engagement with the transverse bar 2 forming the bottom of the opening 4. The second brick is inserted into the same opening but with its smooth side facing downwardly. The free end of the second brick is slightly raised (FIG. 1) to be lowered on the brick underneath as soon as the groove 7 in the brick is in engagement with the transverse bar 2 forming the top of the opening. While the bricks are being thus placed the contacting face of neighboring bricks are provided with a coating of an adhesive bonding agent which bonds the bricks together in the form of a monolithic block.

In the completed block the vertical bars 1 of the lattice 3 bear against the step 8 which conforms in shape with the bar section, whereas the transverse bars 2 are contained in the appropriately formed grooves 7. The lattice 3 is thus firmly incorporated in the finished brickwork block.

For handling the block the lattice 3 is provided with lugs 9 and eyelets 10.

The block shown in FIG. 1 is composed of tapering bricks and the resultant block is therefore suitable for melting equipment containing ring-shaped brickwork, such as an electric arc furnace.

The block illustrated in FIG. 4 is intended for a flat brickwork wall in a melting chamber that requires no special external shell or armor casing. The cold ends of the bricks are fitted into the openings of the lattice 12 to which fastening members in the form of lugs 13 are attached. At its lateral ends 14 which form vertical expansion joints with the ends of the adjoining blocks the cold back of the completed block bears against vertical columns 15 of the furnace structure. The columns each consist of an H-section l6 and a U-section I? placed with its web against the flange of the l-l-section facing the block. The flanges of the open side of the U-section 17 support the ends 14 of the adjoining blocks. The

pressure acting on the inside face 18 of the blocks is transmitted by the lattices 12 to the vertical columns 15.

In an alternative form of construction the ends of the lattice bars of neighboring blocks may be connected for instance where the blocks adjoin at their transverse faces, the connection being rigid if no expansion joint is required and flexible if the joint is to function as an expansion joint.

What is claimed is: i

1. A refractory block for lining the firing and melting chambers of metallurgical furnaces or melting equipment, said block comprising a metal support in the form of a lattice consisting of longitudinal and transverse bars forming rectangular openings and at least one brick positioned in each of said openings of said lattice, each of said bricks adjacent the outwardly facing end thereof having a groove on one longitudinal side thereof, and recessed portions on the adjoining sides thereof, said grooves fitted to said bars extending in one direction, and said recessed portions fitted to said bars extending in the transverse direction.

2. A block as claimed in claim 1, wherein each of said openings of said lattice has positioned therein two of said bricks.

3. A block as claimed in claim 1, wherein said lattice is provided with means for suspending the same, said means comprising lugs and eyelets.

4. A block as claimed in claim 1, wherein the inner face thereof bears directly against the support structure of said furnace or equipment in such manner that columns of said support structure support the end of said block at vertical joints between neighboring blocks.

5. A block as claimed in claim 1, wherein said recessed portions in said adjoining sides of each of said bricks extend from said outwardly facing end of said brick to positions on said adjoining sides beyond said groove.