US2287087A

US2287087A - Apparatus and method for solidification of materials

Info

Publication number: US2287087A
Application number: US333122A
Authority: US
Inventors: Ralph P Clausen; Harold F Vieau
Original assignee: Solvay Process Co
Current assignee: Solvay Process Co
Priority date: 1940-05-03
Filing date: 1940-05-03
Publication date: 1942-06-23
Anticipated expiration: 1959-06-23

Description

June 23, 1942- R. P. cLAUsEN ET Al.

APPARATUS AND METHOD FOR SOLIDIFICATION 1 OF MATERIALS Filed May 5, 1940 2 Sheets-Sheff(l l #afg @a z 7 i ATTORNEY 2 Sheets-Sheet 2 Fv'iled May 5, 1940 R. P. CLAUSEN ET Al.

/ql f mn. Y 2m M NW R WZ/ m NKF T le A d hay @we a APPARATUS AND METHOD FOR SOLIDIFICATION OF MATERIALS Patented June 23, 41942 APPARATUS AND 'METHOD Foa soLmlmcA'rIoN oF MATERIALS Ralph P. Clausen, Yeadon, Pa.,

Vieau, Liverpool, N. Process Company, tion of New York and Harold F.

Y., assignors to The Solvay New YorkfN. Y., a eolpol'a-A Application May 3, 1940, Serial No. 333,122` y' (Cl. A18'26) 14 Claims.

This invention relates to the 'formation of lumps of uniform shape by solidlfying molten material and cutting the solidified material into lumps of the desired shape, for example, cubes, and more particularly, to the formation of matev rials such as cautsic soda and other alkalis and into small cubes uniform inf calcium chloride size.

Caustic soda in the yshape of smalluniform substantially cubicall lumps presents many advantages. In this form it is relatively dust-free and ows readily `from containers inwhich it may be stored. Also, it has a high bulk density about equal to that of ake'caustic and is, therefore, in convenient form for shipping, storing and many industrial uses.

Apparatus for making cubical lumps of caustic soda as heretofore proposed involves an internally cooled drum having continuous circumferential grooves on its periphery and mounted for. rotationwith the grooves of the lower portion of the drum submerged in a bath of molten material, a scraper disposed above the surface of the bath to remove material as it solidifies on the surface of the drum between the grooves, and a knife mounted for reciprocal motion in a radial direction relative to the drum, or a series of knives.

vide a machine comprising a drum having circumferential forming channels, having 'means to place material in the channels on the drum in a manner which causes the material to remain firmly in the channels and to resist forces tending'to dislodge it. It is a further object to provide a machine comprising a drum having circumferential forming channels and having improved means to divide the material into uniform lumps and to remove solidified material from the drum-without displacing the material from the forming channels prior to division into lumps. It is still a further object of this invention to provide al process for producing substantially cubical or other convenient shaped partic1es,uniform in size and shape, from molten material. Y

Other objects and advantages of this invention will be apparent from the following description thereof. l y v The machine of our invention comprises` a cooled rotatable drum having continuous circumferential forming channels and means to-supply drum into which the drum dips. When the latr mounted radially on a wheel for cutting the solidied material in the grooves the desiredv lengths. In the operation of such apparatus it e was found that the action of the Acutting knife or vknives tended to displace the material .being cut from the grooves, resulting in the production of non-uniform lumps and irregular fragments. Also,A at times difficulties were encountered in maintaining the solidified material within the grooves prior to the cutting thereof into lumps of desired size and shape.- It was found that the scraper disposed abovethe bath of molten material and adjusted to remove substantially all of the material on the surface of the drum between the grooves, the material upon solidification would have Ya tendency to fall lfrom the grooves. If, on the other hand, material on the surface of the drum between the grooves was not removed by the scraper, irregular lumps having relativelythick edges or flanges projectingfrom one face resulted. Furthermore,l solidified material removed from the surface of the drum and expelled into the body of molten material would interfere with the proper filling ofthe grooves, resulting in lumps of non-uniform size and shape.

It is an object ,of this invention to devise an improved apparatus for forming lumps of uniform size and shape. It

molten material to the drum to lill the channels. The supply means may comprise a weir box at the top of the drum or a bath of material beneath the ter supply means is used, a scraping device placed. just beneath the surface of the material in the bath removes excess material from the circumference of the drum and the drum leaves the bathl with the grooves filled and with a thin film of material on the surface of the drum between the grooves. A cutter is disposed to engage the material on the drumv at a point' on the circumferential y surface thereof, preferably spaced more than 180 from the point at which the drum leaves the bath of molten material in the modification involving the bath, or at least 90 from the point where the molten material is applied to the drum in the e other modification involving the'weir box for applying a regulated iiow of molten material to the drum.` This cutter cutting edge movesdownwardly as well as inwardly while it is cutting the solidified material on the drum, which at the point of cutting carries the material in a downward ,direction, i. e., the

cutter after touching the outer surface of thel ribbonpf solidified material moves downwardly at'a rate at least equal to the rate of movement of the'solidified vmaterial on the drum. By'so doing,

, displace the solidified material from the grooves.

is another object toI pro` 55 is so designed that the,

we have found the cutter does not tend to materialwhich has solidified thereon, so that such material can be removed readily and without disturbing the material in the forming channels by scrapers disposed at the sides of the drum. These scrapers remove the chipped ma terial from the end faces; the material thus removed is not returned to the bath of molten material in solid form, but may be heated and in molten condition returned to the bath.

In the operation of the apparatus for producing substantially cubical lumps of caustic soda, molten caustic at a temperature of from 320 C. to 450 C.,-preferably at a temperature of about 420 C., is supplied to the rotating drum to fill the grooves, the drum beinginternally cooled, for example, by supplying cooling water thereto. Preferably the supply of molten caustic to the drum is accomplished by causing a portion of the rotating drum, suitably from 60 to 90, to be submerged in a bath of molten caustic maintained within the temperature range above indicated, the level of the caustic within the bath being maintained by the supply of material in amount equal to that removed by the drum. The drum may be from 1 foot to 10 feet in diameter and may rotate at such a speed as to provide adequate cooling time to insure solidiflcation of the product and suitable peripheral velocity of the face of the drum. The peripheral velocity is limited by the required speed of the cutter mechanism which should ordinarily not exceed 3,000 strokes per minute. In the case of a drum 3 feet in diameter.' we have found optimum results are `obtained by rotating the drum at a speed within the range of about 1/ to 11/2 R. P. M. to produce a cube having each side 1%" long. This corresponds to a peripheral velocity of from 4.7 to 14.1 feet per minute and a cutter speed of from 300 to 900 strokes per minute. With larger drums, and when making larger cubes, peripheral velocities up to 100 feet yper minute may be used.

' Alternatively, if desired, the drum may be supplied with molten caustic at a point near the top of the drum but at the side of the vertical diameter opposite that at which the knives are disposed, the knives being positioned near the horizontal ,diameter so that the distance between the point of application yofthe molten caustic and the point vof cutting is atleast equal to 90.

Operation of the apparatus in accordance with the process conditions hereinabove outlined, it has been found in practice, results in the pro,-

ductionv of lumps of caustic substantiallyl uniformlin size and shape.-

In the preferred embodimentillustrated in the accompanying drawings-the invention is shown incorporated in a machine for forming cubes of caustic soda, soda ash mixtures, calcium chloride or other such materials, and the present description will be confined to this embodiment of'the invention. It will be understood, however, the-novel features of importance are susceptii'ilev of other application, as, for example, in theformation of other shapes than cubes, or to -thjformation of desired shapes of materials whichj-solidifyupon cooling but which do not .require the application of heat to maintain themin molten condition during the supply thereof -jto the drum, as in the embodiment in the drawings; Hence, the scope of' the invention is not confined to the. embodiment '.herein-'described 'In the drawings, Figure l is an end elevation of a machine embodying this invention;

Figure 5 is a diagrammatic view showing the path of movement of the cutter. i

Referring to the drawings, the construction shown 'in Figs. l to 3 comprises a water-cooled drum l mounted for rotation in the direction indicated by the arrow (see Fig. '1) with trunnions 2 and 3 journaled in bearings 4 bolted to the supporting frame 5. 'I'he power required to rotate the drum is supplied through pulley-wheel 6 which is fixed to an extension integral with trunnion l3. As shown in Fig. 2, the hollow interiors of the trunnions communicate with the interior of the drum for supply of cooling water to and discharge from the drum. Closely spaced continuous circumferential grooves 2', each slightly wider at the top of the groove than at the'bottom, are formed in the peripheral surface of the drum. The grooves may be about 55; wide at the bottom, 1%" at top, high, and spaced apart about 11;". The tops of the walls separating the grooves are fiat. A pan 1 bolted to the frame 5 and lto an anchor 8 ilxed in the foundation is placed beneath the drum and is filled with molten material to a level which covers a portion of the drum. In the case of a drum 3 feet in diameter, the level of molten material is preferably maintained so that about 5 to 6 inches of the drum are submerged.' Electrical heating units S ar'e provided in the bottom ofthe pan 1 to keep the material in heat liqueiiedcondition..

A scraper l0 pivotally mounted at I I is pressed by means ofthe weight and arm I2 against the drum to scrape `excess material therefrom just before the surface of the drum emerges from the molten material in the pan, i. e., the scraper separating the grooves on the periphery of the ydrum beneath theflevel of molten material as 'l-appears from Fig. l.

the drum, and the distance beneath the surface The speed of rotation of of the material at which the scraper is located are adjusted so that after the drum surface passes thescraper a thin layer of material is deposited on the tops of the walls between the grooves on the surface of the drum. This thin `layerconnects the strips of material in the groovesand aids in holding them in place.

At' a point where the 'surface of the drum has rotated about 225 after leaving the material in the pan, a cutter is provided to divide the, strips of solidified material into lumps of substantially uniform sizeU and shape. The lumps fall from the drum l into a chute 29 and are passed to storage. ,The cutter comprises a knife I4 provided with teeth I5' adapted to enter the grooves on the drum, and is mounted at one'end of a pair of holder bars I0. The other ends of the bars I6 are moved in a circular path about a horizontal axis parallel to the axis of rotation of the drum and in the same direction as the direction `of rotation of the drum by an eccentric I1 on shaft l1'. The Shanks ofthe bars ls are sudabie in bearings I8 disposed in a rock shaft I9, the ends of which are journaled in support 20 secured to the frame 5 of the machine so that the the machine illussupport 20'and the rock shaft i9 containing the bearings I8 are fixed` against. horizontal and vertical" movement while permitting .the rotation or rocking of the shaft I9. When the bars I are actuated by the eccentric, the knife I4 moves radially towardsthe drum, cuts the material in the grooves and while cutting the material moves downwardly with the material carried by tiiedrum, the speed of movement of iheknife being such that it moves downwardly at a speed at least equal to the speed of movement of the material in the grooves. After completing the cuttingV the knife moves radially away from the drum. The path of movement of the cutter is depicted in Fig. 5, which shows the layer of caustic on vthe drum somewhat magnified to facilitate the 'showing of the path of movement of the cutter through the caustic. It will be noted from this figure that the cutter travels a path which may be considered as substantially elliptical moving first towards the drum approximately radially with respect thereto, then tangentially with respect to the drum, and finally in a radial direction away from the drum.

The cut-off knife I4 is provided with teeth 2| at each end thereof which are positioned to graze the end faces of the drum and chip the material manipulated by an operator to maintain the box in the desired inclined position to supply material to the grooves in the drum at a rate such that the grooves are completely filled beneath the box. Electrical are positioned in the bottom as the drum passes heating 'means 34 of the Weir box to 'maintain the materialin the Weir box in heat j liquefied condition. Molten material flows from the opening 3| in the Weir box and is led to grooves of the drum and distributed uniformly therein by means of an apron 35 fixed to the` front of the Weir box, the apron being provided with grooves or channels in its upper surface and having its edge formed to cooperate with the surface of the drum to'prevent molten material from passing between it and the drum and running down the drum. The Weir box and apron are positioned to supplya controlled stream of material to the drum at a position, varying with the rate of supply of molten materialand the speed of the drum, slightly before the groovesreach their highest point so that the molten material partially solidifies before reaching the highest solidified there While the knife is cutting the strips of material in the grooves. Scraper blades 22 are held in position between the cut-off knife L,

and the pan to remove the chipped material from the end faces of the drum. The blades` 22 may 'be so held by means of bolts 23 passing through slots 24 in the side wallsof chutes 25 welded to the sides of the pan 1. The slots 24 and bolts 23 permit adjustment of the blades relative to the chutes 25 and the side walls of the drum I as will l be understood. The chipping of the material at the side extremities of the drum, it has been found, enables the Scrapers to remove the material from the end faces of the drum without displacing the material from the grooves. Without such chippingA the scraper blades 22 would cause a mass of material on the end faces'of the drum to buckle and lift off in large segments, which would carry with them solidified material from the grooves of the drum. The solid material removed. from A"tlfe end faces of the drum slides down the chutes 24 and -is discharged at the side of the pan 1. Itis not returned to the molten material in the pan in solid form, but if desired may be heated and returned in molten condition so thatit blends uniformly with the moltenv "material in pan 1. An additional scraper blade 26 having its edge formedto scrape the circumference and grooves of theidrum is held in position against the drum by means of bolts 21 and slots `28 which adjustably-connect the blade 26 with the chute 29 welded or otherwise suitablysecured to the frame 5. This scraper removes any material which may adhere to the grooves Vo r-fperiphery of the drum to prepare them for return to the bath to pick up m'olten material.

In Fig. 4 the machine is shown equipped with means to supply molten material to the grooves ,at the top of the drum. A Weir box 30 is supplied withv -molten material which may be introduced through the open top of the box-at a rate equal to the rate of discharge of this material therefrom. 'I'his box has an opening 3I- in the .lower front f ace and 4is mounted for adjustment relative tothe drum-in curved slots 32 in supports 33 which are welded to the frame 5 ofthe apparatus.

tation is scraped 4tained in pan 1 and displacement of the ribbons of caustic point and does not run down the grooves past the cut-off knife. The material fed to the grooves is soiidiiied into yuniform strips anais divided and removed by the same means as in chine employing a bottom feed.

In operation ofthe apparatus of Figs. 1, 2 and 3 for the production. of substantially cubical the ma- ,lumps of caustic soda, molten caustic is supplied tothe pan 1 at.a rate substantially equal to the rate of removal of caustic from this pan by the rotating drum I. The surface of the drum I is scraped by the scraper IIJ shortly before leavingl the body of molten caustic in the pan 1, and leaves the body of caustic carrying ribbons or strips of caustic inthe grooves connected by a on the narrow peripheral surface of the drum separating the grooves, The temperature at which the molten caustic is mainth'e rate of cooling of the drum are such that the caustic is partially set or solidified when the drum leaves the pan, the setting or solidication of thecaustic continuing during the rotation of the drum sothat when the drum reaches the highest point in its travel the caustic is substantially complet-ely set, i. e., is in solid condition. In the further rotation of the drum -the solid ribbons of caustic in the grooves are cut by the knife I4 which, as above pointed out, moves in a substantially elliptical path, the knife moving downwardly with` the caustic ribbons on the drum duringthe cutting thereof at a rate at least equal to the rate of movement of the caustic carried by the drum. This avoids at a point on the drum above the point where the caustic is contacted by the knife I4. Concurrently with the cutting of the ribbons of caustic in the grooves on the drum, the solidified caustic on the sides of the drum is chipped by the teeth 2| carried by the` knife I4. the solidified caustic from the side walls'of the drum, the solidified caustic being discharged through chutes where it maybe heated and returned in molten by scraper 26 to clean the surface of the grooves as well as the peripheral surface of the drum between the grooves. 'I'his conditions 'the drum for re-entry into the bath of molten caustic. The operation of the apparatus of the modifibelieved, will be obvious from Scrapers 22 effect removal of 25 to a suitable disposal'pcint rection,

toproduce substantially cubical lumps of caustic,

uniform in size and shape. Due to the scraping of the molten caustic adhering to the drum surface prior to the point where the bath of molten caustic so that a thm film of caustic forms on the periphery of the drum connecting the ribbons of caustic within the grooves, and the action of the cutter, which, as above pointed out, moves ting the caustic ribbons to the rate of movement of the caustic ribbons carried by the drum, substantially no displacement of the caustic ribbons from the grooves takes place. Furthermore, dueto the close spacing of the grooves on the drum and the thinness of the nlm on the drum between the grooves, it has been found that little of the film of caustic left on the peripheral surface of the drum between the grooves adheres to the 'cut lump, particularly -after the lcut material has tumbled through the discharge chute for further handling.- Inspection of the product produced in the operation of the above described apparatus lumps uniform in size and shane.

It is to be understood restricted to the present disclosure otherwise than as defined by the appended claims.

We claim:

1. A method of forming solid` lumps from molten material, involving the use of an internally cooled drum having a continuous circumferential forming groove on the -peripheral surface of the drum, which vmet od comprises rotating the drum, supplying molten material tothe groove in the drum during its rotation at a point in the path of movement cient to substantially completely fill the groove, cooling the drum to effect solidification of the material within the groove, and cutting the solidified material within said groove into substantially uniform lumps during the rotation of the drum, at a point in the path of movement oi the drum where the drum moves in a downward di'- the cutter moving radially'towards the drum, and also during the cutting of said strip in the same' direction and at least at the same rate 'of speed as the rate of speed of the strip of material. l

2. A method of forming solid lumps from molten material, involving the use of an internally cooled drum having closely spaced continuous circumferential forming grooves on the peripheral surface thereof, which method comprises maintaining a bath of molten material at asubstantiallylconstant level beneath the drum, with the lower portion of the drum submerged in said bath of molten material, rotating and cooling the drum at a rate such that the forming grooves therein are substantially completely lled with molten material at the point Where the drum leaves the said bath of molten material and the material is solidified in said grooves, scraping the surface of the drum during its rotation at a point just beneath the level ofy the bath of molten material so that the drum carries a thin film of molten material on the surface of the drum vbetween the forming grooves connecting strips of material in the grooves, and dividing the solididownwardly while cut-v at a rate at least equal of the drum where the drum moves in an upward direction, in amount suffi-- by cutting the same the `drum leaves sho'ws it to be constituted of substantially cubical u that the invention is not fied materialin the 'grooves into uniform lumps during the rotation of the drum at a point in the path of movement of the drum near the horizontal axis of the drum and 'where the drum moves downwardly, the cutter moving radially towards the drum and during the cutting of the strips of material also in the same direction and at least at the same rate ofspeed as the rate-of speed of the strips of material in said grooves.

3. A method. of forming substantially cubical lumps of caustic soda, involving the use of an internally cooled drum having closely spaced continuous circumferential forming grooves on the peripheral surface thereof, which method comprises maintaining a bath of molten caustic at a temperature of from 320 C. to 450C. at a substantially constant level beneath the drum, with the lower portion of the'drum submerged in said bath of caustic soda, rotating and cooling the drum at a rate such that the forming grooves therein are substantially completely filled with caustic soda at the point where the drum leaves the saidbath of caustic soda and in the continued rotation of the drum the caustic soda in said grooves becomes solidified, scraping the surface of the drum during its rotation at a point just beneath the level of the bath of caustic soda so that the drum carries a thin film of caustic soda on the surface of the drum between the forming grooves connecting strips of caustic soda in the grooves, and dividing the solidified caustic soda in-the grooves into uniform lumps by cutting the same during the rotation of the drum at a point in the path of movement of the drum near the horizontal axis of the drum and where the drum moves downwardly, the cutter moving radially towards the drum and-during the cutting of the strips of caustic soda also in the same direction and at least at the same rate of speed as the rate of speed of the strips of caustic soda in said grooves.

4. A method of forming solid lumps from 'mol- 'ten material, involving the use of an internally cooled drum having closely spaced continuous circumferential forming grooves on thev peripheral surface thereof, which method' comprises maintaining a bath of molten material at a substantially constant level beneath the drum, with the lower portion of the drum submerged in said bath of molten material, rotating and cooling the drum at a rate such that the forming grooves therein are substantially completely filled with molten material at the pointwhere the drum molten material which comprises an internally `v` 'cooled rotatable drumhavlng a circumferential forming groove, means to supply molten material to the groove wherein it is cooled and solidifledln a continuous strip, and cutting means to .divide the solidified strip into substantially uniform lumps, said cutting means being mounted for movement in a substantially elliptical path so that the' cutting .means moves radially towardv the strip ofmaterial, cuts it into. lumps,r and withdraws and also-has a component ofrnove-` from molten material which ment in the same direction and at least at same rate of speed as the strip of material in forming groove while in contact therewith.

6. A machine for producing formed solid lumps comprises an internally cooled rotatable drum having a plurality of closely spaced continuous circumferential grooves mounted for rotation about a horizontal axis With the grooves in a lower portion of the drum immersed in a bath of the molten material to pick up and solidify the material in uniform strips, and cutting means to divide the solidified strips into substantially uniform lumps, said cutting means comprising a knife having teeth formed in its edges adapted to enter the grooves and divide the solidified material into lumps, the knife being mounted for movement in a substantially elliptical path so that the -knife moves radially toward the strips of material, cuts them into lumps, and withdraws and also has a component of ,movement in the same direction and at least at the same terial in the therewith.

7. A machine for producing .formed solid lumps from-molten materialwhich comprises an internally cooled rotatable drum having continuous circumferential molten material to the grooves wherein it is cooled and solidified in continuous strips, and cutting means to divide the solidified strips into substantially uniform lumps, said cutting means being mounted at one end vof a bar, driving means connected to the other end ofthe bar for moving it in a circular path about an axis parallel to the axis of the drum, and a bearing fixed against horizontal and vertical movement through which bearing the bar is slidable, said bar, bearing and driving means being constructed and arranged so that the cutting means has a component of movement in the same direction and at leastat the same speed as the strips of material while in cutting relation thereto.

8. A machine for producing formed solid lumps from molten material which comprises an internally cooled rotatable drum having closely spaced continuous circumferential grooves, means comprising a channeled plate to supply a controlled stream of the material to the circumferential grooves at a point where it will partially solidify before -the grooves reach their the the forming grooves while in contact highest point, the plate being formed to prevent molten material from running past it down the drum, and cutting means to divide the material into substantially uniform lumps when it has become solidified, said cutting means being mounted at one end of a bar, driving means connected to the other end of the bar for moving it in a'circular path about an axis parallel to the axis of the drum, a bearing fixed against horizontal and vertical movement through which bearing the bar is slidable, said bar,.bearing and rate of speed as the -strips of magl'OOVeS, means 'IO Supply' driving means being constructed and arranged so that the cutting means has a component of movement in the same direction and at least at the same speed as the strips of material while in cutting relation thereto.

9. A machine for producing formed solid lumps from molten material .which comprises an internally cooled drum having continuous circumferential grooves mounted for rotation about a horizontal axis, with of the drum immersed in a bath of the molten material to pick up and solidify the material in uniform strips, cutting means having a comthe groovesin a lower portion` ponent of movementin the saine direction and at least at the same speed as the strips to divide the solidified strips into substantially uniform lumps, and scraping. means mounted at theend faces of the drum between the cutting means and' the bath toremove solidfled material from the end faces of the drum and prevent it from enteringthe bath of molten material, said cutting means vbeing provided with teeth adapted to chip the material which has solidified on the end faces of the drum to ing means. A y

10. A machine for producing formed solid lumps 'from molten material which comprises an internally cooled drum with continuous circumferential grooves mounted for rotation about a horizontal axis, with the grooves in a lower portion of the drum immersed in a bath of the molten -material to pick up and solidify the masurface a thin layer of the material to assist 1n retaining the strips of material in the grooves, and means to divide the strips into substantially uniform lumps when they have become solid.

11. A machine for producing formed solid lumps from moltenmaterial which comprises an internally cooled drum with continuous circumferential grooves mounted for rotation about a horizontal axis, withthe grooves in a lower p0rtion of the drum immersed in a bath' of molten material to pick up and solidify the material in uniform strips, means mounted near but below the surface of the molten material to scrape the circumference of the drum just prior to its leaving the bath to solidified on the surface of the drum between the grooves while leaving on that surface a -thin layer of the material to assist in retaining the strips of material in the grooves, cutting means to divide the solidified strips into substantially uniform lumps, having a component of movement in the same direction and at least at the same speed as the material while in cutting relation therewith, and scraping means mounted at the end faces of the drum betweenv means and the bath to remove solidified material from' the end faces of the drum to prevent it from entering the bath of molten material, said cutting means being provided with teeth adapted to chip the materialwhich has solidified on the end faces of the drum to facilitate its removal by the scraping means.

12. A` machine for producing formed solid lumps from moltenmaterial which comprises an internally cooled drum having continuous circumferential grooves mounted for rotation about a horizontal axis with the grooves in a lower portion of the drum immersed in a bath of the molten material to pick u-p and solidify the material in uniform strips, means mounted near ,but below-the surface of the molten material to scrape the circumference of the drum just prior to its leaving the bath to remove excess material which has solidified on the surface ofthe while leaving a thin drum between the grooves o layer of material on that surface to aid in retaining the strips of 'material in the grooves, a knife having teeth into substantially uniform lumps and additional facilitate its removal by the scrapof the, molten material to remove excess material which has the cutting teeth adapted to chip the material which has solidified on the end faces of the drum to facilitate its removal from the drum, a bar fixed to said knife. driving means connected to said bar for moving it in a circular path about an axis parallel to the axis of the drum, a bearing which is fixed against horizontal and vertical movement through which bearing the bar is slidable, said bar, bearing and driving means being constructed and arranged so that 'the .cutting means has a component of movement in the saine direction and .at least at the same speed as the material in the grooves when in contact therewith, and means mounted at the end faces of the drum between the cutting means and the bath to remove the solidified material from the end faces of the drum and prevent it from entering the bath of molten material.

13. A machine for producing substantially cubical lumps of caustic soda comprising an internally cooled drum with continuous circumferential grooves mounted for rotation about a horizontal axis, with a lower portion of the drum immersed in a bath of molten caustic soda to pick up and solidify the caustic soda in strips, cutting means having a component of movement in the same direction and at least at the same speed as the strips of caustic soda to divide the strips into substantially cubical lumps, scraping means mounted at the end faces of the drum between the cutting means and the bath to re- A lmove solidified caustic soda from the end'faces of the drum and prevent it from entering the bath of moltenl caustic soda, and teeth on said cutting means adapted to chip the material which has solidified on the end faces of the drum to facilitate its removal by the scraping means.

14. A method of forming substantially cubical lumps of caustic soda, involving the use of an Ainternally cooled drum of from one to ten feet in diameter having closely spaced continuous circumferential forming grooves on-the peripheral surface thereof, which method comprises maintaining a bath oi' molten 'caustic at a tempera- 'ture of from 320 C. to 450 C. at a substantially constant level beneath the drum, with the lower -portion of the drum submerged in said bath of caustic soda, rotating the drum at a peripheral velocity\not exceeding 100 feet per minute, and cooling the drum at a rate such that the forming grooves therein are substantially filled with caustic soda at the point where the drum leaves the said bath of i caustic soda and in the conr tinued rotation of thirum the caustic soda in the grooves becomes solidified, scraping the-sur' face of the drum during itsrotation at a point just beneath the level of the bath of caustic soda so that the drum carries a thin film of caustic soda on the surface of the drum between the forming grooves connecting strips of caustic soda in the grooves, and dividing the solidified caustic soda in the grooves into uniform lumps by cutting the same during the rotation of the drum at a point in the path of movement of the drum near the horizontal axis of the drum and where the. drum moves downwardly, the cutter moving radially towards the drum and during the cutting of the strips of caustic soda also in the same direction and at least at the same rate of speed as the rate of speed of the strips of caustic soda in said grooves.

RALPH P. cLAUsEN. HAR/om F. VIEAU.