US32426A - Improvement in furnaces for smelting iron ore - Google Patents

Description

P. KERR. I

Blast Furriace.

No. 32,426. Patented May '28,-1861.

NITED, STATES PATENT FICE.

PATRICK KERR, OF NEW BETHLEHEM, PENNSYLVANIA.

Specification forming part of Letters Patent No. 32,426, dated May '28, 1861.

Y0 all whom it may concern.-

Be it known that I, PATRICK KERR, of New Bethlehem, in the county of Olarion and State of Pennsylvania, have invented and discovered certain new and useful Improvements in Smelting Iron Ore with Raw Bituminous Coal;

and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawing, making a part of this specification.

I only consider it requisite to describe the interior of the furnace.

Ais the stack above the bosh; B, the chamber between the boshes, termed the hearth C, an openmetallic thimble at the top of the stack; a a, the cap-plate. D D are fines partially opposite the thimble, and D flue placed below the others; E E, openings for the tuyeres; c, an opening at the back of the hearth at a slightlyhigher level than others. I) b and 1 1 are the lines of the bosh which are continued up at a second angle to d. '00 and 2 2, continued to d d, is a second form,while 3 3, continued in an unbroken line to cl (1, is a third form, which may be called a hearth and no bosh; and these modifications are more specifically described hereinafter.

Theinnerbosh (marked 1 1) is the form-to be employed when semi-bituminous coal is to be used. The intermediate form (marked 22, 8m. is that for ordinary bituminous, and that marked 3 3, &c., for coal in which the bituminous is in excess. There may be other modifications of form under the controlling law that as the coal becomes more bituminous the elbow or bosh is to be proportionally diminished.

It is well known that in bituminous coal there is a great difference of quality, arising, chiefly, from the proportion or quantity of bitumen therein. Previousto my discovery of taking advantage of these qualities the employment of these coals in a crude or raw state had been attended with difficulties so greatas to prevent there use in successfully smelting iron ore. By a long continued course of operations and observations I have traced one of the difficulties to that property of expansion or swelling of the bitumen in the coal by which the proper working of the furnace was impeded, thus causing the' charge of coal and ore to hang and work unevenly, and the furnace to jump when a very large amount of stock comes to work at once. I further effect a great saving of fuel by my improvementsat least twenty-five bushels of coal foreach ton of metal madeand by the creation ofa more intense heat from the consumption of the gases (otherwise lost in coking) a greater. amount of steam from the boilers employed in the blast is obtained, while the hot-blast itself is increased in temperature. The increase of heat also throws off the sulphur into the slag or dissipates it.

The nature of my improvement consists in the discovery of such modifications of form to be given to the furnace that each variety of bituminous coal may have a form of construction to suitits'properties, and thus all descrip tions of raw bituminous coal may be employed for smelting iron ore. In addition to the advantages above alluded to the quality of the iron is decidedly improved and quantity in-- creased. out of the same amount of stock. The saving of labor in handling the coal in coking is not to be overlooked, and the prevention of jumping, which secures the even working of the furnace by the regularity of setting,prevents the chilling thereof, which is a very important item. The improvement in the quality of the iron by the-reduction of the amount of fuellessens the consequent quantity of sulphur in the charge, and the increased degree of intensity of heat liquefies the metal, thus allowing of its being more perfectly purified in its passage through the cinder. My introduction of a thimble in connection with the openings for the flues conveying the escaped gases to the boilers and hot-blast delivers the stock more in the center of the furnace, keeps it from the walls, prevents the escape of gas at the tunnel-head, and enables me to work with a lower stack.

The following directions for the inside may serve as a general guide in building one of my furnaces. That shown in the drawing is twelve feet across the bosh and forty feet high. The inclination of the line of the hearth from 1 to b is two inches to the foot-rise, then from b to e five inches inclination. This is for asemibituminous coal. For bituminous, the bosh is to be between the extremes delineated 2, c, and d. The exterior figure-via, from 3 to d, and which is without an angle-is for coal in which the bitumen is in excess, The bottom of the smallest hearth is four feet at its base, the next six, and the outside one eight feet in diameter, with a projection of about three feet beyond thislast circle, and in width two feet. The dam f two feet high, the side tuyeres, E E, are five inches, and the back tuyere, 6, seven inches above the top of the dam. The nozzles are three inches in diameter, observing that the bottom of the openings and tuyeres should be level. The thimble 0 should be four feet high and of the inner diameter of the stack at the tunnel-headviz., four feet. It is best made of boiler-iron having a flange which catches on the cap-plate. About a foot below its top there are three holes for the admission of atmospheric air and igniting the gas in the thimble when the charge is above the bottom thereof. The openings D D for the flues are three feet high and twenty inches wide, arched at top, so placed that their bottoms will be seven feet below the'capplate and rising one foot above the lower edge of the thimble. The second pair of. flue-holes, D (one shown) have their bottoms about tcn feet below the cap-plate.

In charging the furnace, the quantity of coal should not exceed fifteen bushels.

Having described my improvement, whatI claim as my invention, and desire to secure by Letters Patent, is

The use of bosh and hearth constructed as hereinbefore described and set forth, in which the width or proportion is reduced or enlarged as the quantity of bitumen in the coal employed as fuel is increased or diminished.

' In testimony whereof Ihave hereunto signed my name before two subscribing witnesses.

Witnesses:

JOHN F. CLARK, EDM. F. BRoWN.

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