US1681808A

US1681808A - op london

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Publication number: US1681808A
Authority: US
Publication date: 1928-08-21
Anticipated expiration: 1945-08-21

Description

`Aug. 2l, 1928,

J. S. MORGAN HEAT TREATMENI` OF SUBSTANCES BY MEANS OF MOLTEN METAL Filed Nov. 20. 1922 Patented Aug. 21, 1928.

UNITED kSTATES PATENT OFFICE.'

JOHN STANLEY MORGAN, OF LONDON', ENGLAND, ASSIGNOR TO THERMAL INDUSTRIAL AND CHEMICAL (T. I. C.) RESEARCH COMPANY LIMITED, 0F LONDON, ENGLAND.`

HEAT TREATMENT `OF SUBSTANCES BY MEANS OF MOLTEN METAL.

Application filedA November 20, 1922, Serial No.

In processes of subjecting materials to heat treatment by means of molten metal or alloy it is generally necessary to avoid removing the metal from the bath togethery with the treated material. When the material is in comparatively large pieces there is no particularly difliculty in fulfilling this necessity; but when powdered, granular, librous or other nely-divided material has to be removed it is difficult to avoid the presence of globules of metal in the discharged material.

I have found that it is possible to carry finely-divided material from the surface of molten metal in an upwardly moving cur rent of elastic Huid, and that the material carried from the surface in this manner is free, or substantially free from molten metal'. It is sufficient tocreate or maintain a difference between elastic fluid pressure within the apparatus and thatwithout it, so as to cause a flow of elastic fluid outwardly from the vessel; by causing the current of elastic fluid to pass over the material to be removed, and to take an upward course, the material may be entrained in the current of elastic fluid and removed from the surface of the molten metal. The elastic fluid leaving the still, and the material carried in suspension, may then be separated in any convenient manner.

Apparatus for carrying out the foregoing method comprises a still which .contains molten metaL and is gas-tight,` except for the means of exit vafforded by a discharge pipe arranged to Ventend upwardly, and with its lower end invclose lprorimity to the surface of the molten metal. Treated Ymaterial is caused to collect on the surface of the molten metal beneath the lower end of the dischargevchute, and is carried through the chute.,` and discharged vatkthe upper end thereof, by means of avcurrent of elastic fluidgleaving the apparatus by way of the discharge chute.

When the heat treatment is a process of destructive distillation or the like in which elastic fluid products are evolved, the pressure exerted by these productswmay be used for expelling the residual product of the distillation from the vessel which serves as the retort and contains the molten metal. For instance, when a material like saw-dust is being carbonized it may be so conveyed Vover or through .the molten metal that the 602,188, and in Great Britain January 4, 1922.

carbonized product collects beneath a nozzle which is fixed .clear of the molten metal surface and is attached to a pipe which eX- tends to the outside of the vessel. In such case the pressure of the gas and vapour evolved from the fresh sawdust which'is being carbonized will carry the carbonized `material through the pipe which may deliver it to a separator where it is removed from the gas and vapour, preferably before any condensation occurs, and any particles of metal that may be Amixed with the carbonized material which lremains in the still will be absorbed again in the molten bath.

l/Vhen the heat treatment is one that does not evolve elastic fluid, or evolves too little to create the required pressure, steam or other suitable elastic fluid may be introduced into or generated in the vessel. This is often desirable in order to assist the distillation.

In order to take advantage of this method of discharge it is often desirable to provide for the crushing of the residual product inside the vessel before the expulsion of the product. It is possible by this means to introduce. the material in larger pieces, and Yto treat materials which cake together during the course of the heat treatment or distillation, the crushing means serving to reduce large or caked pieces to particles of such size that no difficulty is experiencedin Vtheir discharge by the method of the invention.

The accompanying drawings illustrate an apparatus which operatesin accordance with the invention, Fig. 1 being a longitudinal vertical section and Fig. 2 a cross section on line A-B of Fig. lj

The material, such as wood chips which are to be' dest-ructively distilled, is fed through a gas-tight feeding device (not shown) down a chute a into the tank b containing molten lead c. vIt is caught bythe blades Z of a drumc revolving in the direction indicated by the arrow and is thereby carried through the metal to return again to the surface in front of the rollers f which extend across the tank. The lower roller is driven, so that, as ythe material is piled by action of the drum against the rollers, it is caught between them` and passes on in. a suitably crushed condition.

.v The gas-tight cover of the tank has a manhole suitably lsealed by acover g havingl lill handles li. The tank is divided into compartments above the surface of the molten metal by a transverse vertical partition 'i in which is an opening to receive the `curved upper edge Ic of a plate Z shaped like a hood and having an upward extension m which slides against the partition a' `to `make -a substantially gas-tight joint. The plate Z is fixed to a screw spindle a working in a nut 0, so that by rotating the latter the plate can be raised or lowered. The plate Z extends across the tank, land-as the material is pushed forward by action of the rollers f, it passes beneath the plate. 'The opening afforded by this hood-shaped plate, however, Vis the sole passage for the `elastic fluid produced by the Adestructive distillation, and in escaping through this opening the elastic fluid carries with it the charred material. The latter is deflected by the curved edge t' into the chute p whence it is removed by a gas-tight discharging device (not shown), while the elastic fluid escapes rby the pipe q. The distance of the lower edge of the plate Z from the surface of the lead is so adjusted to ensure that the 4es-icaping elastic fluid has a velocity sufficient to raisetlie material without lifting up to the discharge opening any globules of metal from the heated metal bath. Globules of lead which may ascend towards vthe opening in the partition i, together with the material to be removed, fall back into the lead bath before they arrive at the opening.

The bearings of the rollers f `are mounted in arms o", one oneach side of the tank, which can be `fixed `at .an angle suitable for the size of material under treatment, by pins engaging in perforations in the arms and in corresponding sectors s,

llVhen the angle of inclination to the hori zontal ot' the plane containing the axes of the rollers 7*' is small, the effective pocket formed is suitable for the reception of coarscr particles, which are then carried between the rollers by the positive rotation of the lower roller. Under these conditions, however, material in a finer state of subdivision tends to heap up and pass over the upper roller, and in the case ot' such material this tendency is diminished by 'increasing the angle of inclination to the horizontal of the arms r. i

The apparatus described is suitable for treating materials which, during this treat ment, evolve sufficient elastic fluid for carrying the treated material out of the still. 'If it is required to treat materials which do not evolve elastic fluid, or evolve too little to produce the contemplated effect, the ap paratus may easily be adapted for this pur pose by providing at any suitable place an inlet pipe (not'shown) for the introduction of steam or other elastic fluid or a material which will yield an elastic lluid in the still.

Having thus described the nature of the said invention and the best means I know of carrying the same into practical ellect, I claim l. kIn processesof subjecting lto heat treatment, by contact withV a bath olE molten metal, materials which yield `by the treatment a solid residue of lower specific gravity than the molten metal, the method of re-y moving the solid residue from the surface of the molten metal in a condition substantially 'free from metal, which consists vin causing the residue `to .accumulate on the surface of the vmolten metal beneath an upwardly directed duct and to be entrained in a stream ofi? elastic fluid 'moving upwardly through the duct.

2. In processes of subjecting to heat treatment, by contact with a bath ol molten metal7 materials which yield by the treatment elastic fluid and a solid 'idue of lower specific gravity t an the molten metal, -the method of removing the solid residue from the surface of the molten metal in a condition substantially free from metal which consists in causing the residue to accumulate on the surface of the molten metal beneath an upwardly directed duct and to be entrained in a stream of the elastic fluid product of the treatment moving upwardly through the duct..

3. In processes of carbonizing, by contact with a bath of molten metal, carbonizable materials which yield on carbonization elastic fluid and a solid residue of lower specific gravity than the molten metal, the method of removing the solid residue from the surface of the molten metal in a condition substantially free from metal which insists in causing the resldue to accumulate on the surface of the molten metal beneath an upwardly directed duct and to be entrained in a stream of the elastic fluid product of the carbonization moving upwardly through the duct.

4. Apparatus for subjecting materials to heat treatment by means pof molten metal, comprising a still to contain. molten metal, andan upwardly directed discharge chute formng the sole normalmeans ol exit Yfor elastic fluid from the still and having its lower end arranged to be in close proximity to and above a part of the surface ofthe molten metal, and adjustable with respect to the distance of its lower end from the surface of the molten metal.-

5, Apparatus for subjecting materials to heat treatment by means of molten metal, comprising a still to contain molten metal',` a gas-tight feeding chute adapted to feed the material to be treated to the molten metal, an upwardlyl directed discharge chute forming the sole normal means of exit for elastic fluid from the still and having `its lower end arranged to be in close proximity to and liu the molten metal from t-he feeding chute to' the discharge chute.

6. Apparatus for subjecting materials to heat treatment by means of molten metal comprising a still to contain molten metal, a gas-tight feeding chute adapted to feed the material to be treated to the molten metal, an upwardly directed discharge chute forming the sole normal means of exit for elastic fluid from the still and having its lower end arranged to be in close proximity to and above a part of the surface of the molten metal, means `for causing the material to be treated to Y travel in contact with the molten metal from the feeding chute to the discharge chute, and rollers situated intermediately of the feeding chute and the discharge chute and adapted to crush the treated material before it enters the discharge chute.

7 Apparatus for subjecting materials to heat treatment by means of molten metal, comprising a still to contain molten metal, a gas-tight feeding chute adapted to feed the material to be treated to the molten metal, an upwardly directed discharge chute forming the sole normal means of exit for elastic fluid from the still and having its lower endarranged to be in close proximity to and above a part of the surface of themolten metal, and adjustable with respect to the dstance of its lower end from the surface of the molten metal, means for causing the material to be treated to travel in contact with the molten metal from the feeding chute to the discharge chute, and rollers situated intermediately of the feeding chute and the discharge chute and 4adapt-ed to crush the treated material before it enters the discharge chute.

8. Apparatus for subjecting materials to heat treatment by means of molten metal, comprising a still to contain molten metal, a gas-tight feeding chute adapted to feed the material to be treated to the molten metal, an upwardly directed discharge chute forming` the sole normal means of exit for elastic fluid from the still and having its lower end arranged to be in close proximity to and above a part of the surface of the molten metal and adjustable with respect to the distance of its lower end from the surface of the molten metal, means for causing-the material to be treated to travel in contact with the molten metal from the feeding chute to the discharge chute, rollers situated intermediately of the feeding chute and the discharge chute and adapted to crush the treated material before K it enters the discharge chute, and a pipe located. exterior of the discharge chute and commune-ating therewith for drawing off the elastic fluid escaping from the still with the treated material.

9. Apparatus for subjecting materials to heat treatment by means of molten metal, comprising a still to contain molten metal, a gas-tight lid to said still, a gas-tight chute adapted to feed the material to be treated to the molten metal, an upwardly directed discharge chute extending through a wall of said still and forming the sole normal means of exit for elastic fluid from the said still, said discharge chute having its lower end arranged to be in close proximity to and above a part of the surface of the molten metal, means for adjusting the distance of the mouth of said discharge chute from the sur face of the molten metal, a drum situated near to the feeding chute and intermediately of the feeding chute and the discharge chute, said drum being partially immersed in the molten metal and adapted to be rotated on a horizontal axis, vanes on the said drum, rollers having their axes parallel to each other, said rollers being adjustable in respect of the angle of inclination to the horizontal of the plane containing their axes and being situated intermediately of the feeding chute and the discharge chute and adapted to crush the treated material before it enters the discharge chute and a pipe located exterior of the discharge chute and communicating therewith for drawing off' elastic fiuids escaping from the still with the treated material.

In testimony whereof I have signed my name to this specification'.

JOHN STANLEY MORGAN.