US1572779A - Apparatus for heat treatment by means of alpha bath of molten metal - Google Patents

Description

Feb. 9,1926. 1,572,779

A. MCD. DUCKHAM APPARATUS FOR HEAT TREATMENT BY MEANS OF A BATH OF' MOLTEN METAL Filed June 20, 1923 Il. 0 gy Pam-med` Feb. 9, 192e.

UNITED STATES PATENT OFFICE.

ARTHUR-MUDOUGALL DUCKHAM, 0F LONDON, ENGLAND, ASSIGNOR T0 THERMAL INDUSTRIAL .AND CHEMICAL (T. I. C.) RESEARCH COMPANY LIMITED, 0F LON- DoN, ENGLAND.

LAPPARATUS FOB HEAT TREATMENT BY MEANS OF A BATH OF MOLTEN METAL.

Application led June 20, 1923. Serial No. 646,616.

To all whom it may concern.'

Be it known that I, ARTHUR MCDOUGALL DUCKHAM, a subject of the King of Great Britain, residing in London, England, have invented certain new and useful Improvements in Apparatus for Heat Treatment by Means of a Bath of Molten Metal, of which the `following is a specification. v

In British Patent No. 14,617 of 1895 to McEuen there is disclosed an apparatus for causing material to travel through a bath of molten metal while submerged in the metal, which apparatus consists of an endless chain or band travelling around drums within a closed vessel containing the molten metal; the upper run of the chain travels at some distance above the surface of the metal and the lower travels beneath the surface of the metal. The chain carries at short distances projecting transverse arms and between these the material under treatment is charged on to the chain from a hopper at one end of the vessel so that the material h is conveyed to the other end where it is car- 2 ried over the drum at this end and is returned beneath the surface of the molten metal.

The considerable heat capacity of the chain operates adversely in such an `ap a.- ratus. The upper run is cooled by radiation and by the material charged, particularly if the material is moist, and on becoming the lower run is apt to freeze the molten metal in contact with it; thus the material delivered on to the surface of the metal from the lower run carries metal with it and the pivots of the chain become bound by the metal, greatly increasing the friction and even stopping the travel. Furthermore much of the eat imparted to the chain is lost to the bath with bad economy.

The present invention in large degree obviates these objections by keeping the lower run or stretch of the chain clear of the molten metal. To the same end, metal plates which are relatively thin, as compared with the arms disclosed in said British patent, and, by reason of the fact that 4they absorb comparatively little heat, do not materially chill the molten metal, may be employed.

To reduce still further the mass of metal constituting the conveyor, the thin plates may be bent at right angles so that between the parts which project at right angles to the chain thereV are formed platforms on which the material to be treated rests. In this manner the chain can be reduced in width to that necessary for the strain which it has to bear, or there may be more still narrower chains.

To avoidsagging of the upper run or stretch of the chain or chains and to take the upward thrust on the lower run or stretch when the molten metal is of higher specic gravity than the metal plates, the latter may be supported at their ends on ledges below them on the inner surfaces of the walls of the vessel during their travel with the upper run andy against like ledges above them during their travel with the lower run..

A construction according to the invention is shown in the accompanying drawings.l

Fig. 1 is a longitudinal section througha bath of molten lead and a furnace for heating the lead, the bath containing a conve or aving the features of the invention; ig.

scale, on line 2-2 of Fig. 1.

` The bath a, set in a furnace b and having a gas tight cover c, is charged' with liquid lead to the level d. The lshafts Z carry each two sprocket wheels e and on each pair of these wheels runs an endless chain f. The two chains carry a number of plates g of sheet iron as thin as is constructionally permissible, which are bent at right angles, the horizontal limbs being rivetted to the links of the chains. Angle irons h, z' bolted to the sides of the bath support the ends of these plates in the manner already indicated.

It will be seen that the diameter of the sprocket wheels is such that the lower runs or stretches of the chains are just above the surface of the molten lead while the horizontal limbs of the plates are just on the surface.

Each plate with that next it constitutes a bucket to receive material as it passes beneath the charging hopper 7c. One of the shafts Z being driven in the direction indicated by the arrow, the charged buckets are conveyed to the other end of the bath where they enter the molten met-a1 carrying with them the material, which has been pre-heated and dried during its travel on the upper run. 'The material thus travels through the lead and at the charging end of the bath substituted two or 1s a cross section, drawn to anA enlarged is delivered on-4 to the surface of the molten plates E, they' may be suitably perforated.

' The be treated in such an apparatus as here described are known. As an example ofsuch material shale may be mentioned;

Having thus described the nature of my said invention and the best means I know of carrying the same into practical effect, I claim 1. Apparatus of the character described,

Acomprising a chamber to contain molten metal, a chain travelling through said chamber above and in close proximity to the normal level of the metal in saidchamber, and

transverse plates projecting from the chain and dipping below the said level.

2. Apparatus of the character described, comprising a chamberv to contain molten metal, an endless travelling chain lying above the normal level ofthe metal contained in said chamber and having a stretch which is in close proximity to the said level, and transverse-plates attached to and projecting from the chain, and extending below the said level when they are positioned on the said stretch.

v 3. Apparatusof the character described, comprising 'a chamber to contain molten metal, horizontal shafts mounted in said chamber, sprockets on said shafts situated above the normal level of the metal, an endless chain travellingaround said sprockets with its lower run above and in close proximity to the said level, a plurality of transverse plates projecting from said chain and dipping beneath the normal level of the metal when positioned on the lower run of the chain, means for rotating one ofthe said shafts, means for feeding the material to be treated into the chamber, and means chamber.

, 4:. Apparatus of the character described, comprising a chamber to contain molten metal, horizontal 'shafts mounted in said for removing the treated material from the chamber, sprockets on said shafts situated above the normal level of the metal contained in said chamber, an endless chain travelling around said sprockets. with its inds of material which may usefullyV lower run above and in close roximity tov the said level, a plurality o thin metal ing its other limb projecting perpendicularl from the chain and dippin beneath sai level when positioned on the Iower run of the chain, means for rotatingA one of the said shafts, means for feeding material to be treated between the pro'ecting limbs of the plates when positione run of the chain, and means for removing the treated material from the chamber.

5. Apparatus of the'character described, comprising a chamber to contain molten metal, horizontal shafts mounted in said chamber, sprpckets'on said shafts situated above the normal level of the metal contained in said chamber, an endless chain travelling around said sprockets with its lower run above and yin close proximity to thesaid level, a pluralit of transverse plates projecting from sai chain and dipping beneath said level when positioned on the lower run of` the chain, ledges on the sides of 'said chamber supporting said plates during their travel between the sprockets,

means for rotating one'of the said shafts,y

means for feeding material to be treated into the chamber and means for removing the treated material from the chamber.

6. Apparatus of the character described, comprising a chamber/to contain molten metal, horizontal shafts mounted in said chamber, sprockets on said shafts situated abovejtlie normal level of the metal in said chamber, an endless chain travelling around said sprockets with its lower run above and in close proximity to the said level, a plurality of thin* metal plates 'bent at right angles and leach havingvone limb secured to said chain and its other limb projecting perpendicularly from the chain and dipping beneath such level when positioned on the- 'ARTHUR MCDOUGALL nUoKHiM.

on the upper

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