US2888255A

US2888255A - Boelens

Info

Publication number: US2888255A
Authority: US
Publication date: 1959-05-26
Anticipated expiration: 1976-05-26

Description

6 1959 E. BOELENS 2,888,255

OPEN-HEARTH FURNACE WITH INCLINED SIDE WALLS Filed March 2, 1953 INVENTOR.

[DE/9RD Bantams a/iiwz/ 1M United States Patent OPEN-HEARTH FURNACE WITH INCLINED SIDE WALLS Edgard Boelens, Grivegnee, Belgium, assignor, by mesne assignments, to Socit anonyme Cockerill-Ougree, Seraing, Belgium Application March 2, 1953, Serial No. 339,668 Claims priority, application Belgium March 7, 1952 3 Claims. (Cl. 263-46) The present invention relates to a furnace which is used in heavy metallurgy and such for example, as a furnace for melting, refining, reheating, thermal and other treatments.

It is known that, in certain furnaces, the necessary heat is supplied by hot gases resulting from a combustion or by an effect due to an electric current.

In present-day furnaces of large dimensions, for heavy metallurgy, heated by hot gases resulting from a combustion, the walls are generally vertical as in reheating furnaces or firing furnaces or inclined towards the exterior of the furnace, as for example, in Martin furnaces that is to say that, in known large furnaces the size of the transverse cross section inside the furnace is constant or runs in a curve in a continuous manner from the hearth to the arch.

Known furnaces of this type have disadvantages among which may be mentioned particularly, the presence of waste spaces at the apex of the pillars near the arch. There exist in these localities turbulent gaseous currents which cause local wear in the refractory lining and diminish the efiiciency of the transmission of heat between the materials to be heated and the hot gases. Furthermore, the components of the arch may partially melt and fall in droplets on the pillars which they attack it being assumed that they are often of a different chemical nature.

The present invention consists in providing in a furnace of a large dimension for heavy metallurgy an arch independently formed of a plurality of elements and overhanging the side walls having internal surfaces shaped in such a manner that if they are extended they intersect at a point which is a finite distance above the hearth.

According to an essential feature of the invention, the independent arch is composed of a number of elements held in a frame if desired braced and constituting an assembly independent of the side walls. The internal surfaces may be flat or curved and they extend in a continuous fashion between the hearth and the arch beyond the openings of the working doors. In the case where the surfaces are flat, they make, with the horizontal plane passing at the level of the hearth, an angle which varies according to the type of apparatus, the working conditions, etc. The angle of inclination of the surfaces to the horizontal is generally between 45 and 85. If the internal surfaces of the lateral walls are curved, the concavity is directed towards the interior of the apparatus. In some embodiments the opposing curved surfaces have, at points at the same level, identical radii of curvature, the radii of curvature can also be different so that it is also possible to give to the lateral walls and to the independent arch the same radii of curvature.

The present invention will be more easily understood by reference to the following description of the attached drawing which shows purely as an illustration, an embodiment by way of example of the invention.

The figure is a diagrammatic view, in part perspective, of a Siemens-Martin furnace, the front surface being removed.

It will be seen from the figure that a Siemens-Martin furnace comprises a heanth 2 mounted, for example, on the support beams 2 On the hearth are mounted the lateral walls 3 which, according to the invention, are inclined towards the interior of the furnace that is to say the interior surfaces 3 are brought closer together as they approach the arch 4. The latter, independent of the inner walls 3, is composed of a plurality of separate elements such as bricks, the whole of which is kept together in a frame not shown. On both sides of the arch 4 which overhangs the inner walls 3, are placed the suspension beams 4 of the said arch and to which are attached rods such as 4 In one wall 3 are arranged charging doors such as 3 in front of which, in the opposite Wall tapholes such as 3 are situated. It can be seen in the figure that the surfaces 3 are curved and extend in a continuous manner between the hearth and the arch.

One characteristic of an apparatus constructed according to the invention resides in the fact that the independent arch, of a plurality of elements, possesses a surface the projection of which onto a horizontal plane is less than that of the hearth projected onto the same plane.

Among the various advantages of a furnace according to the invention may particularly be mentioned the very appreciable reduction of the span of :the arch which results in a decrease in weight of the refractory, increased strength and much more rapid and easier repairs.

In addition, in the case where the refractories of the arch and the lateral walls are of different chemical natures capable of giving rise to destructive reactions for one or other of these parts, the structure of a furnace according to the invention prevents the direct contact between the fusion products of the refractory components and, as a result, prevents a chemical reaction between them and the consequent accelerated deterioration of these linings such as is produced by the sweating of the arch.

Moreover, the most rational section of the furnace produces a better distribution of the hot gases of the flame which are driven down towards the bath or towards the objects to be heated and the elimination of the waste spaces which, in the present-day furnaces of straight transversal section or flared upwardly, favour the upward movement of the hot gases.

Finally for the same hearth surface the refractory linings overhanging the latter have an external radiating surface less than the correspondingly known furnaces; the loss of heat in a furnace formed according to the invention will thus be less than in the latter.

What I claim is:

1. An open hearth furnace of the Siemens-Martin type having a hearth, side walls alongside said hearth, an arch overhanging said walls, said side walls having inwardly inclined surfaces so as to reduce the span of said arch.

2. An open hearth furnace of the Siemens-Martin type having a hearth, side walls alongside said hearth, an arch overhanging said walls, said side walls having inwardly inclined surfaces so as to reduce the span of said arch, said surfaces being flat and inclined in a continuous manner between said hearth and said arch.

3. An open hearth furnace of the Seimens-Martin type having a hearth, side walls alongside said hearth, an arch overhanging said walls, said side walls having inwardly inclined surfaces so as to reduce the span of said arch, said surfaces being fiat and inclined in a continuous manner between said hearth and said arch J at an acute angle comprised between 45 and 85 with the horizontal plane at the level of said hearth.

References Cited in the file of this patent UNITED STATES PATENTS 743,271 Grifiiths Nov. 3, 1903 796,175 Baggaley Aug. 1, 1905 931,945 Mehner Aug. 24, 1909 1,286,794 Sahlin Dec. 3, 1918 1,297,149 Greene Mar. 11, 1919 41, Tcroutman Mar. 24, 1925 Norton Oct. 9, 1928 Wonning July 1, 1930 Moore May 23, 1939 Robertson Apr. 1, 1941 Pollen June 9, 1953 FOREIGN PATENTS Australia Oct. 25, 1951 Australia Nov. 26, 1951