US1807307A - Apparatus for melting finely divided materials - Google Patents

Description

" A. DAWANS' May 26, 1931.

APPARATUS FOR MELTING FINELLY DIVIDED MATERIALS Filed July 12, 1928 I V. //////f" Patented May 26, 1931 PATENT OFFICE I AnRiENnAwANs, or BRUSSELS, BELGIUM APPARA'rns Eon MEILTIIN'G FINELY nIvInEn MATE IALS Application .filed July 12, 1928, SerialNo. 292,211, and in BelgiumJ'u ly 29, 1927.

This invention relates to apparatus for melting finely divided materials comprising a stationary inclined bed plate along 7 which the melted materials slide by gravity.

With a view to replacing the material which has melted and flowed away, the zone of melting and flow is situated, according to the invention, at the foot of a pile of material, the angle ofvslope of which is the natural 1 angle of repose of the material.

In order to prevent an agglomeration of the finely divided particles which would interfere with the flow of the molten metal, the invention provides a screen formed for exis ample by a refractory wall by means of which the melting zone can be limited near the upper part of the hearth.

The invention further involves a particular embodiment wherein the zone in which the said material is led in a molten state may be situated in proximity to the lower end.of the bed plate or may abut against the inclined surface of the pile.

Further, according to the invention, the

26 gases of combustionmay be led at a certain distance from the melting zone bymeans of a screen formed for example by a refractory wall. In order to permit use to be made ofmechanical devices adapted to serve, in par- 30 ticular, for advancing the material, the two screens mentionedmay produce in the hearth a zone which is at a lower temperature than that'of the melting zone and which'will be adapted to receive the saidmechanical deas vices.

WVith a view to oxidizing in the upper part of the hearth certain oxidizable elements such as carbon, pyrites,-etc., which may be contained' inthe said material, the invention fur- 40 ther provides for an additional admission of way of example and in a non-limiting man ner two embodiments of the invention.

The latter extends to the various original features which the arrangements shown comprise.

Figure l-is a perspective view with a part out awayof the device constructed for melting the said materials.

- charges into and solidifies in vessels 270 Figure 2 is a perspective view of the device with a screen. I i

The hearth comprises a bed plate 2a inclined at approximately 20 to the horizontal so as to discharge by gravity, over the downwardly-curved lip 2g at the end of the bed plate, the molten product which is obtained at 2f under the action of burners 3a supplied either with blast furnace gas or with pulverized coal, etc. The melting may, however, be obtained also by means of simple coal-burning hearths.

In order to effect the automatic feeding of the material to replace that which has been melted, the material to be treated, which is poured into the chute 4, descends the latter by gravity andflows out through the lower aperture 4a thereof onto bed plate 221 where it forms a pile, shown in dotted lines, whose surface 4?) assumes naturally, when at rest, an inclined or sloping position known as its natural slope or angle of repose. a

To vary'the amount of the material supplied to the hearth and thus changethe slope 4b, the aperture taofthe chute l (which lat ter is situated in the interior of the gasdischarging chimney 5) may beclosed a movable sliding door 470 balanced by a counterweight 4 and the position of which can be controlled from the outside by suitable means (not shown). p

The melting of the material takes place at the foot of the slop 4b, and the molten metal flows along the inclined bed plate and displaced at the end 2g of the said hearth.

In order to make complete use of the heat contained in the fuel, the above mentioned material, which is fed to the hearth in a direction opposite to that in which the burning gases are discharged, is heated by the latter in the chute 4 and at the upper part 4m of the slope 4b.

With the object of preventing an'influ'x of cold air, the end or lip 2g of the hearth is partly closed by a movable wall 2t so as to leave merely a sufficient passage for the discharge of the product from the melting operation.

In the case of Fig. 2, in which the construction is approximately the same as in Fig. 1, the material is led in proximity to the end or lip 29 of the said bed plate 2a where melting takes place under the action of burners 3b supplied with blast furnace gas, or with pulverized coal, etc. In this form, the melting zone is limited by means of a screen formedby a retractory'wallfia which is rigidly connected with the side walls 2;) of the hearth and is arranged at a short distance from the end 29 of the hearth; the screen a lso comprising a top wall or member 5f which overhangs the lower part of the-sloping pile and directs the hot gases trom the molten material toward "the upper part 4m of the pile where they heat the material. The two walls 5a and 5; may be integral, producing a structure of L-section.

For the purpose of reducing the dept-h or th-icknessiof the material at the melting point 2;", the wall 5a is caused to penetrate into the sloping surfaceofithe pile in such a way as to produce asecond natural slope 4 9 which has a different inclination than the first or main slope.

In order to prevent too rapid solidification of the molten product and .the formation of chains of solidified grains of material starting lirom-theend 2g of the .bed -plate,-the said product, before .falling into the vessels 276 in which it solidifies, passes through a sheet of gas .at a very l'i-igh temperature obtained by arranging the burners-3b opposite and slightly below the said end 2g.

The gases coming from the melting pass in a conduit constituted by a refractory wall such as 5;, the side wallssuch as .2p, the upper wall Off the hearth adjacent to the said side walls, the incline of .the material to be melted represented in the drawings by dotted lines toward the top of the hearth v2 where at 4mthey reheat said material.

By the arrangement of these re'factory walls 5a and with-in the hearth "2, a zone 2m is produced in the hearth which is at a lower temperature than the melting zone 2 in which none 2m it will be possible to dispose mechanical devices such as blade wheels, etc.

In order to reduce further the temperature of (the zone 272a, air admission tuyeres 55 (shown in dotted lines) may project into this zone above or inadvance of the said wall 5a.

As :a result of the addition of the amount of supplementary air a certain part of the carbon containedin the material. charged into chute 4 and which may be formed by blast furnace dust, is burnt at 4m. The combustion of this carbon contributes in heating the material at am andconsequently increases the eliiciency of the apparatus.

In the operation of the invention, dust from blast furnaces may be treated in a hearth analogous to "the one hereinbefore de scribed, during which treatment the ferric oxide contained in this dust is transformed into ferrous oxide under the action of the heat before the products reach the end or lip 2; in the melting zone.

hat I claim is:

1. Apparatus for melting finely-divided material, comprising a chamber provided with an inclined, fixed bed plate; a vertical duct situated at the upper end of the bed plate and through which the finely-divided material is introduced, said duct having an aperture in its bottom through which the material escapes and forms a pile extending along the "bed plate and having its greatest height comprised between the upper edge of said aperture and the "bed plate; melting means acting upon a definite portion of material situated at the intersection of the upper inclined surface of the pile and the plane of the bed plate; and a chimney surrounding theduct for discharging the gases of combustion.

2. Apparatus for melting finely-divided material, comprising a chamber provided with an inclined, fixed bed plate; avertical duct situated at the upper end of the bed plate and through which the finely divided material is introduced, said duct having an aperture in its bottom through which thematerial escapes and forms a pile extending along the bed ,plate and having its greatest height comprised between the upper edge of said aperture and the bed plate; melting means acting upon a definite portiono'f material situated at the intersection of the inclined surface of the {pile and the ,plane of the bed plate; means for varying the height of said aperture so as to change the position of the foot of the pile in respect to said melting means; .and a chimney surrounding the duct fordischarging the gases of-combustion.

3. Apparatus for melting finely-divided material, com-prising a chamber provided with an inclined, fixed bed plate; a vertical duct situated at the upper end of the bed plate and through which the finely diivided material is introduced, said duct having an aperture in its bottom through which the material escapes and forms a ipi-le extending along the bed plate and having its greatest height comprised between the upper edge 01f said aperture and the bed zplate; melting means acting upon a definite portion of material situated at the intersection of the in- (fl'ined surface oft-he pile'and the plane ofthe bed plate; a chimney surrounding the duct for discharging the gases of combustion; and a screen located between ithe (melting :zone and the material to be melted, and directly behind the melting zone, said screen ,-provid ing an upper free space tor the passage of the gases and a lower-one for the entrance of material into the melting zone.

4:. Apparatus for melting finely-diwided material, comprising a chamber provided with an inclined, fixed :bed pl'ate; zfl vertical duct situated at the upper end of the bed vplate and through which the finely-divided material is introduced, said duct having an aperture in its bottom through which the material escapes and forms a pile extending along the bed plate and having its greatest height comprised between the upper edge of said aperture and the bed plate; melting means acting upon a definite portion of material situated at the intersection of the inclined surface of the pile and the plane of the bed plate; a chimney surrounding the duct for discharging the gases of combustion; a screen located between the melting zone and the material to be melted, and directly behind the melting zone, said screen providing an upper free space for the passage of the gases and a lower one for the entrance of material into the melting zone; and a second screen associated with the first one to form at the upper part of the apparatus with the walls thereof a conduit through which the gases of combustion are material, comprising a chamber provided with an inclined, fixed bed plate; a vertical duct situated at the upper end of the bed plate and through which the finely-divided material is introduced, said duct having an aperture in its bottom through which the material escapes and forms a pile extending alon the bed plate and having'its greatest height comprised between the upper edge of said aperture and the bed plate; melting means acting upon a definite portion of material situated at the intersection of the in: clined surface of the pile and the plane of the bed plate; a chimney surrounding the duct for discharging the gases of combustion; and an L-shaped screen, one branch of which is located between the melting zone and the material to be melted while the other branch is located in the upper part of the apparatus above the material to be melted.

6. Apparatus for melting finely-divided material, comprising a chamber provided with an inclined, fixed bed plate; a vertical duct situated at the upper end of the bed plate and through which the finely-divided material is introduced, said duct having an aperture in its bottom through which the material escapes and forms a pile extending along the bed plate and having its greatest height comprised between the upper edge of said aperture and the bed plate; melting means acting upon a definite portion of ma terial situated at the intersection of the inclined surface of the pile and the plane of the bed plate; a chimney surrounding the duct for discharging the gases of combustion; an L-shaped screen, one branch of which is located between the melting zone ADRIEN DAWANS.

and the material to be melted while the other branch is located in the upper part of the

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