US2265511A - Bessemer converter - Google Patents

Description

Dec, 9, 1941. H. A. BRAssERT BESSEMER 'CONVERTER Filed Dec. 1 193s 2 Smets-'sheet 1 Dec. 9, 1941.

H. A. BRASSERT BESSEMER CONVERTER Filed Dec. l, 1938 2 Sheets-Sheet 2 Patented Dec. 9, 1941 UNITED STATES PATENT OFFICE BESSEMER CONVERTER Herman Alexander Brassert, Bovington, England, assignor to H. A. Brassert & Company, Chicago, Ill., a corporation of Illinois Application December 1, 1938, Serial No. 243,300 In Great Britain December 8, 1937 (Cl. 26S-35) 2 Claims.

j to be used under better control.

In the accompanying diagrammatic drawings are shown, in

. Figures 1 and 2, side and front elevationsv respectively of a converter constructed in accordance with the'present invention; and, in

Figures 3 and 4, side and front elevations respectively of a modification of the converter shown in Figures 1 and 2.

The ordinary converter, since the date of its invention by Bessemer, has been in the form of a cylindrical vessel, tapered off at the bottom, and contracted at the nose to form a spout, the main portion of the belly being cylindrical. 'I'he bottom is perforated by the conventional number of tuyre holes; the lower periphery of the converter lining approximately coincides with the periphery of the converter bottom on which the metal. bath stands. The converter lining slopes upward from this periphery at a steep angle to the centre cylindrical portion of the converter.

Practice has shown that a converter newly lined in this manner does not give the best results with regard to output, yield and metal losses. A newly lined converter suiiers from heavier spitting and colder working than a converter in which the lining has been partially eaten away. The reason for this is that the metal driven upwards in the direction of the wind above the tuyres finds no return path to the bottom, whereas when the converter is more worn, the metal runs upward above the tuyres and flows downwards along the walls, partially permitting a revolving motion.

This invention has as its purpose to facilitate this circulationof the bath in a new converter,

' preventing the metal and slag being driven upward and out of the nose of the vessel and, on the contrary, allowing the bath to remain quiet and in a smooth upwardly flowing motion from the tuyres and downwardly'along the walls. By this motion, a uniform action of the oxygen of the air on the metal is produced during lthe upward ilow, metal returning on the periphery of v the vessel only'when it is again exposed to the action of theair blast, this cycle being repeated continuously., with the result that every part of the metal is brought in contact with the air and no part of it is over oxidised compared with other parte. asmust bethecase whengreat metal are thrown up in a boiling mass in the centre. Wind going through the tuyres in the majority of known converters met .with uneven and constantly varying quantities of metal resulting in uneven action, and it is another object of the present invention to eliminate this disadvantage.

v.According to the present invention there is provided a Bessemer converter having a partspherical base tted with a tuyre box of circular section, wherein the ratio of the volume of metal in an imaginary cylinder above the tuyres to the volume in the annulus surrounding that cylinder is not greater than 3/1 in the newly lined converter.

According to another feature of the invention there is provided a Bessemer converter having a part-spherical base tted with a tuyre box of circular section, wherein the ratio of the radius of the converter at 750 mms. above the bottom to the radius of the tuyre box is not less than 3/2.

Preferably the part-spherical base merges into a frusto-conical belly portion, and that part of the base which carries the metal during blowing is lined with a refractory material such as one or more of chromium oxide, clay and magnesia.

One form of converter constructed in accordance with the invention is shown in Figures 1 and 2. The lower portion of the walls I1 is substantially spherical and merges smoothly into an upper frusto-conical belly portion I8. In Figures 3 and 4 is shown a modiiication which is some-4 what narrower than that shown in Figures 1 and 2. As before, it comprises a spherical lower portion merging into a frusto-conical portion.

In both forms -of the inventionv` illustrated, it

will be seen that the volume of metal in an imaginary; cylinder I9 above the tuyres is approximately the same as the content of the metal in the annular ring 20 around this cylinder, even when' the converter lining is new. When the converter lining becomes worn the proportion becomes still more favourable for the return of the metal to the bottom. Infany case the ratio of the 'volume in the cylinder I9 to that in the annulus 2n isnOt'gx'eater than three to one in a newly lined-converter.

Y In both forms of the invention illustrated in Figures 1, 2, 3 and 4, the height h of the bath is assumed to be '750 mms. and at this height above the bottom of the converter the ratioof masses of o1 the tuyre box" is meant the radius o! that circular area of the box over which are distributed the tuyre passages.

f In the narrow form of converter shown in Figures 3 and 4,. the wind box is made of smaller section in order to accommodate the larger volume of metal and slag, although the total area of they air blast is maintained the same as usual. It will be seen that in a converter of this shape the blow is quieter, because the metal tends to circulate smoothly in the general direction indicated by the arrows A, upward4 above the tuyres, and downward near the walls, the spherical shape of the walls assisting this action. The spitting is thus reduced to a minimum, the losses are thereby much reduced, and also are less because by the quiet working of the blow, the over-oxidation of parts of the bath is avoided.

Lastly, with a converter of this shape a larger slag volume can be carried without the danger of spitting because of the greater room in the bottom of the converter to carry this slag. This means that, for instance, in the basic Bessemer process a higher percentage of silicon can be 'carried in the metal requiring larger additions A bridging piece 2| substantially of wedge shape is inserted between the usual trunnion ring 22 and the frusta-conical wall I8 of the new converters, said bridging piece being surmounted by a ring 23 of angle section bolted to the trunnion ring and the converter shell.

As shown in Figures 1, 2, 3 and 4; that portion of the converter lining carrying the molten metal during the blowing process is lined with a refractory material 24 such as one or more of chromium oxide, clay and magnesia. By this means Wear is reduced and the circulating effect due to the new shape is kept substantially constant at the optimum.

I claim 1. A Bessemer converter comprising a central tuyre box in the bottom, and bottom and side walls substantially spherical in shape extending from adjacent the outer tuyre openings and I merging directly into inwardly inclined frustoconical Walls.

2. A Bessemer converter comprising a central tuyre box in the bottom, and bottom and side Walls substantially spherical in shape extending from adjacent the outer tuyre openings and merging directly into inwardly inclined frustoconical walls wherein the ratio of the radius of the 4converter at the height of the bath to thev radius of the effective tuyre area is not less than three to two.

HERMAN ALEXANDER BRASSERT.

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