US2507257A - Blast furnace construction - Google Patents

Description

May 9, 1950 s. P.'KINNEY ETAL.

BLAST FURNACE CONSTRUCTION I 5 Sheets-Sheet 1 Filed Aug. 1, 1947 May 9, 1950 s. P. KINNEY ET AL BLAST FURNACE CONSTRUCTION 3 Sheets-Sheet 2 Filed Aug. 1, 1947 May 1950 s. P. KlNNEY ET AL 2,507,257

BLAST FURNACE CONSTRUCTION Filed Aug. 1, 1947 3 Sheets-Sheet 5 3n ta 5 26 SeZwyne fifii'nn g j. [oasis Mfianwick 4% M r W Qttornegs Patented May 9, 1950 2,507,257 BLAST FURNACE CONSTRUCTION Selwyne P. Kinney,

wick, Beaver, Pa.,

Grafton, and Louis M. Hartassignors to S. P. Kinney Engineers, Inc., Pittsburgh, Pa., a corporation of Pennsylvania Application August 1, 1947, Serial No. 765,430

2 Claims.

This invention relates to blast furnaces and is for an improved top construction therefor, better designed to carry the load at the top of the structure, and more particularly to reduce the dust carried out of the furnace at the top by lowering the velocity of the outflowing gases.

The conventional blast furnace as presently constructed has a metal shell lined with brickwork terminating in a top usually made from cast metal and which is of upwardly and inwardly decreasing diameter. Within this conical top is a lower bell through which the charge is introduced into the stock column in the furnace. Above this there is usually a smaller bell located at the bottom of hopper. The charging skip that elevates the charge to the hopper travels on an incline located at one side of the furnace, and a bridge structure over the hopper supports the end of the incline, the dump for the skip, the valve operating mechanism, etc.

As usually constructed, four circular gas uptake pipes lead out of the cone at equally spaced points around the center. They are usually carried up to a great height with the idea that some of the dust entrained in the gases flowing up these pipes may drop back into the furnace, although the high velocity of the gases operates against this. The diameter of these pipes is limited by the diameter of the cone forming the top of the furnace and the space required for the skip and bridge. If their diameter is too great there is not room on the cone for them, and there would not be room between them for the bridge and the skip, etc. Because of their relatively small diameter, the gas velocity in the uptakes is of the order of 3200 cu. ft. per minute.

The uptake pipes of the conventional furnace generally converge, two at each side of the bridge, and join a downtake pipe, known in the art as a downcomer."

Our invention is applicable in the first instance to conventional blast furnaces without substantial alteration therein, and secondly and preferably embodies a reconstruction of the blast furnace top to cheapen it and substantially improve it. The purpose of the present invention is to reduce gas velocities in the top of the furmace and in the uptakes, thereby substantially reducing the amount of dust and size of dust particles that are carried out and at the same time imposing less back pressure on the furnace.

In the accompanying drawings, the invention will be first described as applied to a conventional blast furnace, and then in its more preferred form where the top of the furnace is reconstructed to substantially improve its construction by the use of our invention.

In the drawings:

Fig. l is a front elevation of the upper part of a blast furnace to which our invention is in part applied;

Fig. 2 is a side view thereof:

Fig. 3 is a conventional top plan view;

Fig. 4 is a top plan View, partly in section, of the top of an improved furnace top embodying our invention, the view being a section in the plane of line IV-IV of Fig. 5; and

Fig. 5 is a fragmentary vertical section through the top portion of the furnace structure shown in Fig. 4 with the bell valve shown in elevation.

In the drawings, referring first to Figs. 1 to 3 inclusive, 2 designates the conical top of a conventional blast furnace, and within the top is a lower bell element 3. At the center of the top s a second bell 4 and above this is a hopper In this embodiment of the invention, the customary four uptake pipes are eliminated and in lieu thereof, the sides of the cone below the ring 6 are provided with large elliptical openings which are diametrically opposite each other, and which are at opposite sides of the bridge structure. Extending up from each of these elliptical openings is an elliptical pipe or uptake Hi. The general elliptical shape of these pipes enables them to be of large capacity, as their length on the major axis may be practically as large as is desired, while their dimension on the minor axis of the ellipse is no greater than the conventional round uptake pipes heretofore provided. In other words, the ellipses may extend a substantial distance around the conical top of the furnace, but in the direction of their minor axes they require no more circular pipe which can be led from the conical top of the furnace below the ring 6.

At a point well above the top of the furnace, each of these two elliptical pipes has a downcomer I5 leading from it, the downcomer pipes carrying the blast furnace gases down to the ground level where they are utilized the same as with present blast furnace equipment. Above the point where the downcomers join the uptakes, the uptakes are reduced, providing extensions N5 of smaller diameter, but which are in axial alignment with the main uptakes M. For equalizing pressures, the two uptakes may also be joined by upwardly converging pipes ll. Each of the extensions I6 may be provided with an explosion door I8, and there may be a short pipe l9 leading upwardly from the converging pipes i1, and which is also provided with an explosion door l8.

The two uptakes l4 may be braced and secured to the uprights I! that support the bridge above the furnace top, this arrangement providing a novel construction for bracing the uptakes.

On a conventional blast furnace, these uptakes may extend up as high as one hundred feet on the theory that some dust may drop back, but since it must fall through a rising stream of gas, little useful effect is secured.

room than the maximum diameter.

area, or over four times the area without reduc-- ing in any way the useful space at the top of the furnace, the long axes of the ellipses being parallel with the ways over the top of the furnace for the skip, that is, the long axes are generally tangential to the charging opening. The gas velocity is less than four times as great, with our invention, with the result that far less and only smaller particles are entrained and carried in the gas, which inthe particular furnace referred to, is generated at a rate of about 63,000 cu. ft. per minute figured at a temperature of 60 F., whereas the actual temperature is about 600 F. No advantage is gained by carrying the uptakes above sixty feet, thereby saving a large amount of metal over the conventional construction.

For new construction or general reconstruction of the top, the arrangement shown in Figs. 4 and 5 is even more preferable. In this construction the upper part of the furnace wall has about the same interior contour as at present, but the outside is flared outwardly at 26. The metal shell 21 of the furnace is correspondingly flared out at 28 and is continued above the refractory lining.

A structural metal member or ring 29 encircles the shell of the furnacejust below this flare and may be secured to the shell by gusset plates as shown. A frame'comprised of structural sections 30 extends up from'this ring supportinga circular platform 31 around the top of flared-out top 28 of the shell.

There is a structural frame formed of sections 32 and cross members 33: carried on this platform, and a cast metal charging cone as is carried in this frame along with a bell 35. The operating parts for the bell are not shown, but above this structure the furnace may be constructed in the usual way, there being structural uprights H" to carry the super-structure.

An annular ledge 38 inside portion 28 of the shell supports an outwardly flared lining of refractory 59. Refractory 3S- thussupported independently of the main refractory wall of the furnace.

There are two generally elliptical uptakes 40 from the metal cover plate 4! surrounding the cone. These uptakes are outside the frame members 32. Instead of being true ellipses, they are more nearly of the shape of the segment of a circle with the chord generally tangential to the charging cone. The inner face of each is flat and the outer face rounded. The long axes of these two uptakes are parallel with each other and adequate space is provided between them for a skip to be entered.

With this arrangement the conical top of the present furnace, which is a point of weakn ss, is eliminated and the space increases radially above the top of the stock column to avoid too direct channeling of the gases into the uptakes The weight of the top and super-structure is carried entirely by the shell of the furnace and not by the refractory lining.

With either construction the area of the uptakes is enlarged by using only two uptakes, but putting them diametrically opposite each other and at the sides of the skip trackway or bridge across the furnace top, together with elliptical shape of the uptakes- Plenty of room is provided for the installation or removal of the bell. The form shown in Figs. 4 and 5 has the further virtue of providing an improved top less vulnerable than present ones, and one wherein because of the radial expansion at the top, gas velocities are likely to decrease toward the uptakes, and the tendency is to drop dust before it is carried into the uptakes.

While we have shown and described certain specific embodiments of our invention, it will be understood that various changes and modifications may be made therein in accordance with our invention.

We claim:

1. A blast furnace having a circular top with a central charging opening and a cover in an annular area about said opening, and a single pair of uptake pipes respectively at diametrically opposite sides of the charging opening and in communication with said furnace through said cover, each of said pipes being substantially a segment of a cylinder with its horizontal chord dimension extending substantially tangential to said charging opening and the central point of its arcuate dimension spaced radially from its chord dimension a distance substantially the same as the radial width of said annular area, said chord dimension having a length substantiall greater than the radial width of said annular area, the ends of said chord dimension terminating within the outer periphery of said annular area.

2. A blast furnace having a circular top with a central charging opening and a cover in an annular area about said opening, and a single pair of uptake pipes respectively at diametrically opposite sides of the charging opening and in communication with said furnace through said cover, each of said pipes being shaped in the form of a cylindrical segment having a vertical axis substantially concentric with said opening and annular area, each of said pipes thereby having a flat boundary extending substantially tangential to the periphery of. said opening and the inner periphery of said annular area, and an arcuate boundary having a radius substantially the same as the radius of the outerperiphery of said area, said fiat boundary having a chord dimension in a horizontal plane the ends of which terminate within the outer periphery of said annular area, said chord dimension having a length substantially greater than the radial width of said an nular area.

SELWYNE P. KINNEY. LOUIS M. HARTWICK.

REFERENCES CITED The foliowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 669,012 Kennedy Feb. 26, 1901 1,897,750 Brassert 1- Feb. 14, 1933 2,021,555 Juengling Nov. 19, 1935 FOREIGN PATENTS Number Country Date 701,702 Germany Jan. 22, 1941 OTHER REFERENCES Clements, Blast Furnace Practice, vol. II, Published 1929, by Ernest Benn Limited, London, Bouverie House, E. C. 4, pp 250-252.

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