US1454024A - Reverberatory smelting furijace - Google Patents

Description

May l, 1923.

A. N. JETTE REVERBERATORY SMELTING FURNACE Filed Aug. l0 1920 5. Sheets-Sheet 2 Sum/TOL awo/muy) REVERBBRATORY SMELT I NG FURNACE Filed Aug. l0, 1920 5 Sheets-Sheet 3 @s RL attofmma Mayl, 1923.

A. N. JETTE REVERBERATORY SMELTING FURNACE Filed Aug. l0 1920 5 SheetsfSheet 4 Juve/Mwwm; me La? 5f @um 7M MM May 1, 1923. 1,454,024

A. N. JETTE 'REVERBERATORY SMELTING FURNAC Filed Aug. 1o`, 1920 5 sheets-sheet 5 Patented May 1, 192.3.

UNITED STATES ARCHIE NOEL Jarra, or ANACONDA, MONTANA.

REVERBERATOBY SMELTING FURNACE.

Application filedAugust 10, 1920. SerialrNo. 402,556.

To all whom it may concern.'

Be it known that I, ARCHIE NOEL JE'rrE, a citizen of the United States, residing at Anaconda, in the county of Deerlodge and State of Montana, have invented certain new and useful Improvements in Reverberatory Smelting Furnaces, of which the following is a specification.

This invention relates lto metallurgical smelting furnaces of the reverberatory type, and in particular to reverberatory copper smelting furnaces. l

The main-object of this invention is to provide a reverberatory furnace whereby the metallurgical and mechanical operations are made more convenient and, in general, the metallurgical as well as the mechanical eiiiciency of the furnace improved.'

The improvements relate to various features'of such furnaces including (l) an improved arrangement and construction of the flue connections by which the hot Waste gases, dust and fume from the furnace proper are carried off: (2) an improved arrangement of the furnace bottom; (3) an improved water-'cooled tap-hole and skimming-plate; (4) an improved slaglaunder; (5) an improved arrangement of the longitudinal bracing and tying provisions of a 3o reverberatory furnace, which includes a special construction of side skew-back plates which function also as supports for the main arch of the furnace roof.

The invention will best be understood in connection with the accompanying drawings in which- Fig. 1 is a side elevation, parts being broken away.

Fig. 2 is a vlongitudinal section of the` 40 furnace. l

Fig. 3 isa horizontal section of one end of the furnace.

Fig. 4 is an end elevation of the tapping end of the furnace.

a view in perspective ofthe interior'fof' the furnace at the flue connection.

^ 6 is an elevation of a portion of the end of the furnace showing the water-cooled slahg and tap holes. ig. 7 is a section on plane A-A of Fig. 6. Fig. 8 is a section on plane B-B of Fig. 6. i

Figs. 9 and 10. are a plan and perspective side elevation of the slag launder.

The various features of improvement will be discussed in detail.

1. The #ne connection.

Thisfimprovement refers chieiiy to a flueA for carrying hot waste gases, dust and fume from the furnace proper, designed and constructed with the .idea of providing what might be termed a secondary chamber or beratory type the smelting is accomplished 1 by virtue of the heat from the hot ases or products of combustion from the urnng of the fuel under the reverberatory main arch, the heat being concentrated by reflection from this arch onto the charge.

It has heretofore been the practice,`in reverberatory smelting, to retain the hot gases of combustion in the smelting chamber as long as possible, thus deriving the maximum benefit from the heat of the gases for smelting purposes. -Y The point of exit from the furnace into the flue being the terminal of the reverberatory arch, the hot gases after leaving the furnace proper, enter the enlarged flue connection and expand by Virf tue of this enlargement of chamber, decreasing, therefore, the intensity of heat and decreasing the tendency of the fusible ash and dust carried and precipitated therein to fuse or smelt. A sintering of these precipitated solids takes place permitting their removal through clean-up doors provided for that purpose.

But, in the design 'and construction of this part of reverberatory'furnaces in the past,

the slag dam, on which these sintered solids precipitate, was constructed of such height as to bring its level above the level of the reverberatory arch, thus producing a contracted area in the passageway through which the hot gases carrying the fusible ash and dust vwere compelled to pass into the flue proper. This contraction caused a concentration of heat at this point and a resultant fusing or smelting of the solid material precipitated on or carried over the iioor of the slag dam and flue entrance.

`With such a construction the floor of the rapid rate and resulted in the closing up of" the opening. As this process of closing up continued, the area became less, the 1ntensty of the heat therein became greater.

increasing, therefore, the detrimental effeet of fusing and smclting of the ash and dust carried from the furnace by the hot gases and in general resulting in a choking ofi' of the furnace.

rlhe cross-sectional area of this flue connection was` in the past, purposely made small in an attempt to retain the hot gases in the furnace proper for smelting purposes as long as possible. In many cases a damper in this iue of small cross-sectional area was omitted, because of two reasons the first being1v that the concentration of heat in this small passageway was so intense as to make impossible the use of a damper; secondly, because it was believed that with the design of a flue of small crosssectiona-l area, the flow of hotl gases would be thereby choked and restrained in the furnace, for smelting purposes, and a damper being therefore unnecessary.

My improvement to this part of reverberatory furnaces provides for a radical change in this policy. Instead of attempting to accomplish the desired smelting conditions by a contraction of flue area and the omission of a damper, just the opposite has been done, namely, the flue area has been enlarged and a damper installed.

The improved construction of the furnace will be understood from Figs. l to 5, in which A. is the bed of the furnace, and B the arched roof. The firing end of the fur nace is shown at the right of Figs. l and 2, gas, oil, or coal being used. The flue connection is shown at the left of Figs. 1 and 2.

Referring to Fig. 5, it will be noted that, at the end of the arched roof, there is provided a cross flue or culvert of large crosssectional area. At each side of this crossflue is provided a slag-dam C, of solid masonry construction, whose floor is considerabl below the crown of the roof-arch B, an just above the normal slag-level maintained in the furnace. This lowering of the level of the floor of the slag-dam enables the workmen to remove accumulations thereoncwhile standing on the working fioor of the furnace. Openings D, D, D, closed by suitable Adoors are provided to give the workmen access to the floor of the slag-dam. Movable dampers E, E, are provided at the sides of the cross-flue or culvert.

nace is accomplished to the desired extent.

TheJ closing up of the passageway by accumulation of material fusing to the side walls, on which sticky surface dust readily adheres, is obviated, since any such accumulations are readily removed through openings D, D, D; and the freer flowl of gases causes the solid material carried by the gases to precipitate at points where their removal is easy, and in a fluffy condition which makes them easy to handle. lt thus becomes possible to maintain a full-size flue opening throughout the campaign of the furnace, while obtaining by use of the dampers a close regulation of operating conditions. The improvement is of special importance in connection with reverberatcry smelting where lead, zinc, or arsenic fumes are to be recovered by precipitation in Cottrell treaters, bag-houses and the like.

2. The furnace bottom.

The bottom A of the furnace, which is preferably made of quartz sand is, as shown in Fig. 2, inclined downwardly from the burner end toward the tapping end. There is thus provided a flow of the molten charge to the metal bay, the increased thickness at the burner end filling the lspace which would otherwise be needlessly occupied by metal or furnace charge, thus tying up a large capital in valuab e material as a permanent inventory charge. As these lfurnaces are more than 100 feet long, this item is ofv importance. The slope, depth and character of this bottom is a matter of choice depending on the conditions and requirements in each case.

3. The water-cooled tap hole and skimming plate.

Each tap hole is provided with an apertured tap-hole block 'M held in place by' 4. Slag lau/nder.

To facilitate removal of the slag which Hows from the furnace overthe skimming block I, I provide the outer end of this block with a semi-cylindrical groove por- -tion O, into which fits a correspondingly shaped tongue P on the end of a section of l l the slag launder, each section Q, Q, Q, vhaving at its ends correspondingly/shaped engaging portions. These sections are preferably curved, so that the flowing slag may be delivered to one side of the furnace.

The advantages of such an arrangement are many. It not only provides for a quick and easy removal of the skimming block or any section of the slag launder which may become broken or worn out, but it also pro- Y supports.

The improvements to the furnace bottom with its sloping feature and the installation of the water cooled tap hole plate and skimming block as heretofore described and illus- CII trated make it .possible to operate with a continuous ilow of slag from the furnace. This feature of furnace operation is all important and is only made possible by the design and construction of afurnace with the improvements as stated above. The water ossible to maintain a larger bay of metal. ontinuous skimming is an advantage in reverberatory furnace operations and is believed to be new.

Further improvements, as parts 'of my invention relate to the mechanical construction of the furnace roof and to the means for supportingit.

5. The side .skew-back plates..

These plates are made of beams or girders secured together, and extend along each side of the furnace from end to en d; and function in a two-fold capacity, namely as supports for the main arch of the furnace roof,

and also as ties between the twoends of the furnace. These plates may be of any width desired, even to the extent of covering the whole furnace side. As shown in Fig. 1, the main plate 10, extends the length of the furnace, and is provided at each end with braces 11, 11. The ends of the main plate and the braces, are secured directly to beam structures 12, 12, bearing against theends of the furnace. By the use of these lateral skew-back plates, the tie rods extendi over'the furnace to furnace roof. The former construction necessitated a large number of iron rods of large diameter, which were liable to occasional breaking. The skew-backrplates bear against the sides of the furnace and are held arev eliminated; an head room is provi ed for repairs to the against transverse movement by vertical,

beams 14, 14, and buck-stays. I

As shown in Fig. 2, there are provided at each side of the furnace roof, a series of openings 20, 20, through which the charge is introduced into the furnace.

6. The furnace roof.

At frequent intervals,.along the furnace roof, are arched ribs 21conforming with the ma'in reverberatory arch and built in and connected therewith. These `ribs consist of the same material. as in the reverberatory arched roofl and function as au additional support to the reverberato roof, providing a support for sections of t e roof that have burned thin and would otherwise drop.

The roof is made in sections between which are left openings acting as expansion joints.

The slag launder, tap hole and skimming plate, etc., form the subject matter of applicationSer. No. 434759 filed Jan. 3, 1921, and the side skew-back plates form thesub'ect matter of application Ser. No. 434760 led Jan. 3, 1921.

I claim:

1. A reverberatoi'y furnace comprising a furnace chamber and. means for heati same, a secondary chamber at the exit orming a metal bay, said secondary chamber being of sufficient size to permit the gases coming from the furnace to expand, and an exit flue from the secondary chamber having a damper therein.

2. Furnace according to claim 1 in which the seconda-ry chamber extends a substantialfdistance above the arch of the furnace roo the-i 3. Furnace according to claim 1 in which l 4. A reverberatory furnace comprising a furnace chamber and means for heating the same, a secondary chamber at the exit forming'a metal bay, said secondary chamber extending a substantial distance above the arch of the furnace roof and having a relatively large cross-sectional area suiicient to permit the gases coming from the furnace chamber to expand and a flue having a damper, the

flue being such cross-sectional dimensions as ti to constitute another expansion chamber, in addition to the said secondary chamber, for permitting the gases to expand and thereby materially diminishing the heat concentration at the end of the furnace.

5.A reverberatory furnace as claimed inA claim 1 in which the secondary chamber has located therein a slag-dam whose upperV level is below' that of the crown of the a furnace roof. i c

6. A reverberatoryv furnace as claimedinv claim 2, in whichldoors are provided at vthe upper level of the slag-dam.

of the 7. A reverberatoy lfurnace comprieinga` furnace chamber and means for heating the same, a secondary chamber at the exit form'- ing a metal bay, a flue from the Secondary chamberdeining a slag dam whose upperlevel is below'the crown of the arch ofthefurnace roof, and doorsadjacent the upper level of the slag dam, the secondary chamber having a relatively large cross-sectional area suilicient to permit the furnace gases toex-y pand and the flue having such a large cross sectional area as to additionally cause a niaterial expansion of the furnace gases and a substantial decrease of the heat concentration at the end of the furnace.

8. Furnace according to claim 7 in which the secondary chamber extends asubstantial distance above the arch of the furnace roof and the-llueextends substantially to the roof of the secondary chamber..

9. A reverberatoryfurnace comprising a furnace chamber and means for heating the same, a secondary chamber at the exit formsion of the furnace gases and a material decrease of the heat concentration` atthe end of the furnace. c c

10. Furnace according to claim 9 in which ithe secondary chamber extends a substantial distance above the arch of the furnace roof. y 11. Furnace according to claim l10 in which the flues extend substantially to the roof of the secondaryfchamber. v

.12. Furnace Aaccording to claim 9 including a skimming outlet for slag and a tap hole for matte in the furnace end between the slag dams..

13. Furnace according to claim 2 in which thee'nd of the arched roof of the furnace -is `arched horizontally as well as vertically.

v 14e. A long reverberatory furnace of the vkind described, having a bottom gradually slo'oing from the firing end to the discharge end. means for maintaining a bay' of metal at the discharge end and means for permitting continuous skimming of the slag.

lin testimony whereof, ll ailix my signature.

anciana Noni., Jn'rrn.

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