US1445980A - Copper-matting furnace and method of consuming fuel therein - Google Patents

Description

H. H. STOUT.

Feb. 20, 1923.

COPPER MATTING FURNACE AND METHOD OF CONSUMING FUEL THEREIN.

FILED FEB. 3.1919.

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Patented Feb. 20, 1923.

Units stares 3,445,980 smear ries.

HARRY HOWARD STOUT, OF DOUGLAS, ARIZONA, ASSIGNOR OF FIFTY-FIVE PER CENT TO PHELPS DODGE CORPORATION, A CORPORATION OF NEW YORK.

COPPER-MATTING FURNACE AND METHOD OFOONSUMING FUEL THEREIN.

Application filed February 3, 1919. Serial No. 274,829.

To all whom it may concern:

Be itknown that I, HARRY HOWARD STOUT, a citizen of the United States, residing at Douglas, in the county of Cochise and State of Arizona, have invented certain new and useful Improvements in Copper-Matting Furnaces and Methods of Consuming Fuel Therein, of which'the following is a specification. I

This invention relates to improvements in copper matting furnaces and methods of consuming fuel therein.

I have discovered in the operation of reverberatory furnaces, in the production of copper ore that the rated or actual capacity of such a furnace is far below its maximum or possible capacity. This deficiency in output, I attribute to the very principles upon which the construction of reverberatory furnaces is based, namely, the continual dropping of the arch of the furnace from the firing end to the skimming end. As is well known, the arch is dropped in this manner in order to obtain a reverberation of the flame and its deflection toward and over the ore upon the floor of the furnace, the generally accepted presumption having heretofore been that the heat is transferred to the ore by convection rather than by radiation. I have made the discovery through careful investigation, that the principles upon which the reverberatory furnace is constructed are erroneous and that the most effective method of transferring the heat is by radiation.

Therefore one of the important objects of the present invention is to provide a copper matting furnace Wholly distinct in its characteristic features of construction from the usually employed reverberatory furnace and in which the transfer of heat by radiation, and by radiation alone, is assured, the fur-- nace of the present invention being therefore designed upon principles diametrically opposed to those upon which-the reverberain a givenperi'od of time in a matting furnace'; of; this general type is the controlling factor-in establishing the capacity or output of thejffurnace; the more fuel it is possible to consume in such a furnace, the greater will be the output of the furnace. In the reverberatory furnace, because of the dropping of the arch from the firing end to the skimming end which is considered essential in such a furnace, it is not possible to pass sufficient air through the furnace to support the combustion of a maximum quantity of fuel. The very nature of the furnace inhibits free and unrestricted passage of air therethrough and therefore the quantity of fuel which can be consumed is limited. In other words, in the reverberatory type of furnace the gas outlet is restricted, and as this is one of the disadvantages presented by this type of furnace, it is an object of the present invention to provide a copper mat-- ting furnace having an enlarged gas outlet so that the passage of air through the furnace is unrestricted thus enabling me to consume in the furnace a maximum quantity of fuel. In fact, my method of consuming fuel in a copper. matting furnace constructed in accordance with my invention, involves the principle of utilizing the entire transverse combustion-sustaining area of the furnace for this purpose, and in this respect my invention differs radically from the reverberatory type of furnace in which, in fact, in addition to the restriction of the passage of air through the furnace, combustion is effected only in a more or less hoi izontal zone immediately above the slag line, thus utilizing only a relatively small portion of the transverse combustion-sustaining area of the furnace.

As before stated, one of the objects which I have in view is to provide for the consumption of a maximum quantity of fuel in any given period of time so as to proportionately increase the capacity or output of the furnace, and in addition I employ in my furnace at the firing end a plurality of rows of of a copper matting furnace devoid of the dropping arch, which is the distinguishing feature of the reverberatory furnace, and having an enlarged gas outlet; and second the utilization of a plurality of rows of burners as distinguished from the single row ordinarily employed in the reverberatory type of furnace.

In the accompanying drawings:

Figure "1 is a vertical longitudinal sectional view through a copper matting furnace constructed in accordance with the principles of the pres t invention and in which the methodv of onsuming fuel contemplated by the present invention may be followed out v Fig. 2 is a vertical transverse sectional view through the furnace looking in the direction of the firing end;

Fig. 3 is a similar view looking in the direction of'the skimming end.

It is to be understood that the accompanying drawings are not intended to disclose a constructionwhich must be strictly adhered to in utilizing the principles of the present invention, but that the views of the drawings are intended only to illustrate in a. general'way'an example of a furnace embodying the principles of the invention and in which the method of the invention may be practiced.

In the drawings, the arch of the furnace is indicated by the numeral 1, the floor of the furnace by the numeral 2, the firing end of the furnace by the numeral 3, and the gas outlet in the skimmin end of the furnace by the numeral 4. 'l lie approximate slag line is indicated by the numeral 5.

In the general oblong form of its floor or hearth, the furnace of the present invention does not differ materially from the ordinary reverberatory furnace, and as the length and breadth of the hearths or reverberatory furnaces and, consequently, their hearth areas vary, so with my type of furnace the hearth dimensions may likewise vary although the elongated form thereof is retained.

One of the distinguishing features of my furnace, however, resides in the fact that the arch 1 extends horizontally throughout substantially its entire length. It is true that this arch from a point near the firing end of the furnace is slightly inclined up Wardly in the direction of the said end but this is done solely to decrease deterioration of the arch due to the licking of the flames against this portion thereof. The fact remains that, as stated above, the arch is horizontal throughout substantially its entire length, and by the term horizontal I mean that this arch does not drop continuously from the firing end to the skimming end of the furnace as is invariably the case in the reverberatory type of furnace. In other words, the interior of-the furnace is no more feet in length, the arch being about 84 feet in length and extending horizontally throughout this length except for approximately 23 feet at the firing end where it is inclined with a rise of one foot in the 23. As above stated, this slight inclination of the arch near the firing end is provided solely to decrease deterioration of the arch due to the licking of the flames and it is not intended to, nor can it possibly effect any reverberation of the flames, and in fact may be entirely dispensed with if found desirable. The point to be considered is that the distance between the furnace arch at the skimming end and the slag line is equal to or no less than the distance between the said arch and the Slag line at a point relatively close to the burners at the firing end of the furnace and that between these two points the said arch extends horizontally and is neither dropped nor inclined. In other words, the transverse combustion-sustaining area of the furnace is uniform substantially through the entire length of the furnace.

As before noted, another feature of the invention is the enlargement of the gas outlet 4. Due to the fact that the furnace arch is horizontally disposed throughout its length and the transverse combustion area of the furnace is therefore uniform throughout the length of the furnace, this space is not restricted at the skimming end of the furnace as in the reverberatory type of furnace sothat there is unrestricted passage of. air through this space'and to the gas outlet 4. In stating that this outlet is enlarged,

I- mean that the same is larger in proportion to the other dimensions of the furnace than would be considered good practice in the designing of a furnace of the reverberatory type. In factthe area of this outlet will be such that the flow of gaseous prodnets of combustion from the furnace will approximate 35 feet per second calculated at the temperature of the gases.

In general, in the reverberatory type of furnace but a single row of fuel burners is provided and this row is located transverse- 1y of the firing end of the furnace and at a I larged gas outlet, so that there may be .a non-restricted passage of air through the furnace, and of the gaseous products of combustion from the furnace, which features combined enable me to utilize the entire transverse combustion-sustaining area of the furnace in supporting the combustion of fuel, I provide means whereby a greatly increased amount of fuel may be supplied for combustion, properly distributed, and thoroughly mixed with the air as it is consumed. In accomplishing this result I employ, instead of the single row of horizontal,

burners previously employed and located immediately above the slag line, a plurality of such rows as illustrated in the drawings and indicated by the numeral 6, these rows ofburners being supplied with fuel, as for example by a manifold 7 or each row of burners may be independently controlled without in any way departing from the invention. In the arrangement illustrated 1n the drawings, I make use of three rows of burners, one row, which is the lowermost row and which corresponds to the row heretofore employed in the reverberatory furnace, being located immediately above the slag line, another row which is the uppermost row, being located immediately below the arch 1 of the furnace, and the third row being located sulbstantially midway between the first and second-mentioned rows. Qf course, I am at liberty to employ a greater or less number of rows of the burners, and

the number of burners in each row may be.

varied'in accordance with the dimensions'of the furnace and other conditions. Also, each row may comprise the same number of burn crs or the number may differ in the various rows. By reason of this arrangement it will; be evident that in the operation of the fur- J nace a maximum quantity of fuel will be supplied for combustion, properly distributed, and thoroughly mixed with the air, and that substantially the entire transverse combustion-sustaining area of the furnace will be utilized in supporting the combustion of the fuel, and inasmuch as before stated the capacity of the furnace is increased in ratio to the increase in the amount of fuel which can be consumed therein, it is evident that the capacity or output of a furnace constructed in accordance with my invention and in which fuel is consumed by the method herein described, will be the maximum capacity. For example, the ordinary metallurgical copper matting reverberatory furnace, 18 feet wide and 90 feet long in the ordinary smelting operation has had a daily tonnage capacity of approximately 350 tons. This tonnage has not varied to anygreat extent in any of the ordinary or normal smelters in operation, and in one of these furnacesthe average capacity per day for a year was 344'tons, with a fuel ratio of 7 7/100thsYof a barrel of oil. With a similarly proportioned furnace but constructed in accordance with the principles of my invention and substantially as'illustrated in the drawings, I have succeeded, in carrying out my method, in'reaching a daily capacity of 920 tons with a fuel ratio of 66/ 100ths of a barrel of oil.

In ordinary reverberatory furnace practive, approximately 50 cubic feet of combustion space is required to sustain the comsibly result in a reverberation of the flames and is, as stated, provided merely to prevent deterioration of the arch as far as posslble due to the licking of the flames. For

all intents and purposes the arch of the mattmg furnace embodying my invention is horizontal throughout its entire length, the slight inclination at the firing end being negligible.

Y The fact will be appreciated that because of the distribution of the fuel to a large number of burners, the fuel will become more thoroughly mixed with the oxygen of the air as the fuel is consumed and there will, consequently, be a more rap-id oxidation of the fuel resulting in a more economical consumption thereof.

I have previously pointed out in the description of the furnace that the gas ,outlet is enlarged, or, in other words, is larger than would be considered good practice in the construction of the ordinary reverberatory furnace, taking into consideration the other dimensions of the furnace, and as an example of the relative size of the gas outlet and the transverse combustion sustaining areaof the furnace, such furnaces as have so far been built in accordance with my invention have a transverse combustion sustaining area of approximately eighty-nine square feet and the gas outlet has an area of approximately seventy-seven square feet.

Having thus described the invention, what is claimed as new is: a

1. The method of consuming fuel in a copper matting furnace which comprises propagatin flame over substantially the entire area of fire firing end of the furnace between the slag line and arch.

2. In a copper matting furnace, means for propagating flame over substantially the entire area of the firing end of the furnace between the slag line and the arch.

3. In a copper matting furnace, means for propagating a blast of flame longitudinally of the furnace in the direction of the skimming area thereof and throughout substantially the entire transverse combustion sustaining area of the furnace.

4. A copper matting furnace having a horizontal arch and an escape for the gaseous products of combustion proportioned to de-' aaaaeaa ately above the sla line to a point substantially ediately low the arch.

A copper matting furnace having a combustion-sustaining space of substantiall uniform dimensions, and a plurality of horizontal rows of burners at the firing end of the furnace.

8. A copper matting furnace having a non-dropping arch, and a bank of burners extending substantially from side wall to side wall of the furnace chamber at the firing end thereof.

9. A copper matting ce having a non-dropping arch, and a bank-of burners extending vertically substantially from the slag line of the roof of the furnace chamber at the firing end thereof.

10. A copper mattindg furnace having a non-droppinisarch an a bank of burners occupying su tant1ally the entire transverse area of the furnace chamber at the Ming end thereof.

In testimony whereof I a my signature.

HARRY HOWARD s'ron'r. [n 8.]

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