US3756172A

US3756172A - Furnace roof construction

Info

Publication number: US3756172A
Application number: US00209315A
Authority: US
Inventors: R Brereton; T Lythe
Original assignee: Steetley Ltd
Current assignee: STEETLY Ltd GB; Steetley Ltd
Priority date: 1970-12-22
Filing date: 1971-12-17
Publication date: 1973-09-04
Anticipated expiration: 1990-09-04
Also published as: NO129589B; ZA718386B; DE2163613A1; FI51533B; SE376298B; GB1331459A; AU3718371A; ES398199A1; AU459294B2; FI51533C; CA937963A; FR2119587A5; IT943319B

Abstract

At least one element is hinged to a retaining ring that supports the roof of an electric arc furnace, and is movable from an operative position over the roof to an inoperative position free of the roof. The individual bricks comprising the roof can be held up and/or held down by the hinged element when such is in its operative position, and means are provided for removably fixing the hinged element in its operative position.

Description

ilte States aiem [191 [111 3,756,1 2

Brereton et a1. Sept. 4, 1973 [54] FURNACE ROOF CONSTRUCTION 3,367,292 2/1968 Woodruff et al. 110/99 2,551,941 5/1951 Greene 110/99 [75] Invemms: Ray'mnd memo; 1 773 359 8/1930 Hilliard 263/46 Wilkinson Lythe, both of Worksop, land FOREIGN PATENTS OR APPLICATIONS [73] Assignee: Steetly (Mfg) Ltd., 1,205,692 9/1970 Great Britain 263/46 Nottinghamshire, England [22] Filed: Dec. 17, 1971 Primary ExaminerJohn J. Camby pp No: 209,315 Assistant ExammerHenry C. Yuen Att0rney.iesse B. Grove, Jr.

[30] Foreign Application Priority Data Dec. 22, 1970 Great Britain 60,863/70 1 ABSTRACT At least one element is hinged to a retaining ring that [52] US. Cl 110/99, 13/35, 45322/76429, Supports the roof Ofan electric arc furnace and is [51] Int Cl F23m 5/02 able from an operative position over the roof to an in- [58] Fieid 6 263/46 operative position free of the roof. The individual 52/749 bricks comprising the roof can be held up and/or held down by the hinged element when such is in its operative position, and means are provided for removably [56] References C'ted fixing the hinged element in its operative position.

UNITED STATES PATENTS 3,448,703 6/1969 Hansen et al 110/99 7 Claims, 6 Drawing Figures 9 7 I L\i K 4 PATENTEDSEP 4 um SHEEI 1 OF 4 PATENTED SEP 4 I975 SHEET 2 OF 4 PATENTED SEP 4 I975 SHEEI 3 UF 4 roofs.

Electric arc furnace roofs are generally dome-shaped and the construction of such roofs is usually accomplished by building up the roof within a retaining ring upon a former remote from the furnace. Installation of the roof and its associated retaining ring is achieved by lifiting the roof and ring bodily onto the electric arc furnace as a unit.

If certain types of refractory bricks e.g., basic bricks are employed for the roof, it may be necessary to use a superstructure acting both to support the roof and to prevent the roof bulging upwards during service a socalled hold-up hold-down system. The superstructure provides support, or hold-up, by suspending some or all of the bricks 'of the roof therefrom; it prevents bulging upwards of the roof during service i.e., it provides holddown, by contact between the superstructure and the upper surface of some or all of the bricks. The superstructure is attached to the furnace roof and ring while they are on the former. It is therefore necessary to build the roof within the ring on the former and then, as a subsequent operation, to lift on the integral superstructure and attach the bricks on the roof to the superstructure by means of an appropriate attachment.

When a roof built of refractory bricks is to be repaired the removal of damaged bricks and their replacement by new bricks is considerably complicated by the presence of the superstructure. Overall, therefore, the presence of the superstructure is a problem during repair or replacement of the roof.

It has now been found that the replacement and repair of brick roofs for electric arc furnaces, where such roofs have associated superstructures performing holdup and/or hold-down functions, are appreciably facilitated if the superstructure is constructed as a number of elements adapted to be independently rotatable about peripherally located hinges.

According to the present invention there is provided a superstructure for an electric arc furnace roof adapted to hold-up and/or hold-down part of said roof, which superstructure is substantially annular or part annular in plan view and comprises one or more elements independently hinged to a roof retaining ring.

As well as being useful for dome-shaped roofs, such a superstructure can be used in connection with electric arc furnace roofs which are substantially flat in elevation.

Appropriately each element comprises at least two substantially concentric arc-shaped members connected by one or more transverse members. Preferably transverse members of the element are hinged at the retaining ring but it is possible for the peripheral arcshaped member to be so hinged instead. Preferably any arc-shaped member has an underlying relationship to any shorter arc-shaped members. The arc-shaped members may be adapted to hold-up and/or hold-down the brickwork of the roof.

In one aspect of the invention, bricks which are held down by arc-shaped members are not held-up. Preferably alternate rings of bricks are held down by arcshaped members, the remaining rings of bricks which themselves are not held down being suspended from some or all of the arc-shaped members.

In another aspect of the invention each of the bricks in pairs of adjacent rings of bricks are subject to holddown, preferably by a common arc-shaped member. Desirably the arc-shaped member is also adapted to hold-up the same pair of adjacent rings of bricks. These pairs of rings may adjoin a similarly collocated pair or pairs of rings, or may adjoin rings of bricks subject to either hold-up only or hold-down only or neither holdup nor hold-down.

It is to be understood that the invention further provides an electric arc furnace wherein part of the roof is held-up and/or held-down by a superstructure as hereinbefore described.

The invention will now be illustrated by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a section on the line I l of the view in plan of the roof and superstructure shown in FIG. 2,

FIG. 2 is a view in plan of one embodiment of an electric arc furnace roof and its associated superstructure,

FIGS. 3, 4 and 5 are diagrammatic illustrations of certain methods of hold-up/hold-down used for the roof, and

FIG. 6 is a view in plan of another embodiment of an electric arc furnace roof and its associated superstructure.

Referring to FIGS. 1 and 2, there is illustrated a roof indicated generally by 1 and superstructure therefor indicated generally by 2.

Roof 1 comprises a series of bricks 3 arranged in concentric rings to form a substantially dome-shaped configuration resting on retaining roof ring 4. Alternate rings of these bricks are provided with suspension tabs 5. The roof 1 is provided with electrode ports 12. The roof may or may not be self-supporting and may or may not be arched.

The superstructure 2 consists of a plurality of hinged elements 6 which together in the hinged inwards position, form an annular framework adapted to hold-up and hold-down the underlying brickwork. Each element 6 consists of a series of steel arc-shaped members 7 adapted to overlie alternate rings of bricks, the arcshaped members being joined to and by transverse members 8 which lie radially to the centre of the furace roof. The transverse members 8 are provided with hinges 9 at their outer ends which connect the transverse members with a circular support 10 attached to or integral with the retaining roof ring 4.

During construction of a new refractory roof on a former the elements 6 are folded outwards. When con struction of the roof is completed the elements are folded inwards, each element 6 being locked by means of bolts 11 or other fastening devices to its adjoining elements. The bricks are then attached to the superstructure as necessary. When it is required to repair part of the furnace roof, the necessary number of elements are folded outwards (in FIG. 2 one such element is shown in the folded outwards position) after severing the suspension between the bricks and the elements. The worn bricks can then be removed and replaced without any interference from the hold-up/hold-down superstructure. When the repair has been effected the outwardly folded elements 6 can be returned to their inwardly folded position, locked and the bricks attached to the element by the suspension means.

Some of the various methods which can be used to hold-up/hold-down the bricks are illustrated in FIGS. 3-5.

Referring to FIG. 3 alternate rings of bricks 20 are provided with loops 2i. Hook 22 is attached to the loop of one brick, passed over arc-shaped member 23 and attached to the loop of a brick in the next but one ring of bricks. Alternatively separate hooks can be used to suspend bricks from either of the adjacent arc-shaped members. The arc-shaped member 23 is located above the intervening ring of bricks and serves to prevent any upward movement of this ring.

Referring to FIG. 4, the rings of bricks can be considered in triplets, one ring 24 of which is located below a hold-down arc-shaped member 25 and two

rings

26 and 27 of which are located below an arc-shaped member 28. These latter two rings are provided with

loops

29 and 30 which are attached to a hook 31 which passes over members 28 thereby suspending the bricks. Alternatively separate hooks can be used to suspend bricks from either of the adjacent arc-shaped members. All three rings in this arrangement are subject to holddown but only two rings are subject to hold-up. The

outermost rings are not subject to hold-up or holddown.

Referring to FIG. 5, all but the outermost rings of bricks are provided with loops, typical being 32 and 33. Considering the rings in pairs it is to be noted that each pair of rings such as 34 and 35 are located below an arc-shaped member such as 36.

Loops

32 and 33 are attached to a hook 37 which passes over arc-shaped member 36 thereby suspending the rings of bricks. Equally, member 36 prevents any excessive rise of these rings of bricks, consequently all the rings of bricks in this embodiment are held-up and held-down.

In any of the embodiments illustrated in FIGS. 3, 4 and 5, it is not necessary that every brick in any given ring should be suspended and it is possible, for instance, that only alternate bricks in any given ring are suspended. Also in FIGS. 3, 4 and the outer two rings of bricks may be subject to hold-up and/or hold-down although this is not illustrated as being so.

Referring to FIG. 6 of the drawings, there is illustrated an embodiment of the invention wherein, instead of a superstructure substantially annular in plan view as illustrated in FIG. 1, the superstructure 40 is part annular in plan view and consists of one hinged element 41, attached by fasteners 42 to a centrally located support member 43. Support member 43 consists of three

arcshaped members

44, 45 and 46 connected to a retaining ring 47 by means of radial supports 48.

Naturally more than one such element 41 may be provided if conditions demand it, these elements being located where required.

We claim:

1. In an electric arc furnace, a roof comprised of a plurality of bricks arranged in a pattern, and a superstructure adapted for holding up and/or holding down at least a part of said bricks, said furnace including a roof retaining ring upon which the outer, lower portion of said roof rests, and said superstructure including: at least one superstructure element hinged at one end thereof to said retaining ring, whereby said element is pivotally movable from an operative position lying over said roof, to an inoperative position wherein said element is free of said roof to provide access to bricks lying thereunder when said element is in its operative position, said element when in said operative position having means for holding up and/or holding down at least some of the bricks lying thereunder; and releasable means engageable with said element, and operable for fixing said element in said operative position.

2. In an electric arc furnace as recited in claim 1, wherein said element comprises: at least two spaced, substantially concentric arc-shaped members, connected by at least one transverse member, said transverse member being hinged at its outer end to said retaining ring.

3. In an electric arc furnace as recited in claim 2, wherein said bricks are arranged in concentric rings to form said roof, the bricks in at least some of said rings underlying said element when said element is in said operative position thereof being suspended from said arc-shaped members of said element.

4. In an electric arc furnace as recited in claim 3, wherein the bricks in others of said rings are held down by said arc-shaped members.

5. In an electric arc furance as recited in claim 2, wherein said bricks are arranged in concentric rings to form said roof, the bricks in at least some of said rings underlying said element when said element is in said operative position thereof being held down by said arcshaped members of said element.

6. In an electric arc furnace as recited in claim 1, wherein a plurality of said elements are employed, said elements being arc shaped, and when taken together in their operative positions forming an annular array disposed over said roof, and said means for fixing said elements in their operative positions comprising removable fasteners interconnecting adjacent portions of said elements near the inner ends thereof.

7. In an electric arc furnace as recited in claim 1, wherein said means for fixing said element in its operative position includes: a structural member supported over the central portion of said roof; and removable fastener means adapted to secure the inner end of said element to said supported structural member.

Claims

5. In an electric arc furance as rEcited in claim 2, wherein said bricks are arranged in concentric rings to form said roof, the bricks in at least some of said rings underlying said element when said element is in said operative position thereof being held down by said arc-shaped members of said element.