US2638627A

US2638627A - Method and apparatus for the production of metal powder

Info

Publication number: US2638627A
Application number: US118625A
Authority: US
Inventors: Henry A Golwynne
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-09-29
Filing date: 1949-09-29
Publication date: 1953-05-19
Anticipated expiration: 1970-05-19

Description

May 19, 1953 H. A. GOLWYNNE METHOD AND APPARATUS FOR. THE PRODUCTION OF METAL POWDER Filed Sept. 29, 1949 INVENTOR.

HENRY A. GOLWYNNE BY FVWM H idMwl t ATTORNEYS of streams of the additional gas from the lower to the upper compartment, the openings being openings tend to sweep along the bottom portions s of the upper compartment between adjacent openings to help keep the botto'rn fre tated metal powder. These and other features of the., invention will ecipibe better understood by referring to tl e accom-. panying drawing, taken in cohjiinctionwiththe following description, in which:

Fig. l is a diagrammatic side elevation in section pf 7 an apparat illustrative of a practice of mess-ass l, e'tIIcondiiit, Tfcirltliiesupplifl of ts of cool inert, gas, connects all in en en Q ed :s us'p ension the tasting hr u h he We r i eil," Theseiconduits form part of PW A 5 N b a e s g.

a: i hew;w est-shtsutpiiss sxtra'gas to help heap the 4 tially in the form of a duct; and two side compartments 54 and 56, which are seated from each other as well as from the other two compartments. All of the compartments extend longi- 5 tuclinally of the chamber. The upper and lower compartments are tapered in reverse order. Thus, upper compartment 50 has its smallest cross-section at the right end of the tank, and its largest,. crossection at the left end. The lower. compartment or gasidistributing.duct 52, on the other hand, has its largest cross-section et the right end, where the gas is shown to enter, and its smallest cross-section at the left end."

The compartments are obtained by the use oflopposed pairs of butt-welded plates 6| to B8, top plates to 18 and a pair of spaced side plates BViid 82f They are suitably welded to the cylindricahwafl and to each other to provide an integi'al structure. Plates 6| to 68 are pitched or 31 angles l? 2 99 3 13 Qif thatiiv ds s t e -the i llt V 1, 'in'to 'the bottom of the trough. Referring for a moment toFigl, it will be seen ws s l n w i i Wel d Whith df i'tne. cylindrical tank at the right end to ,prov'id'e fa slot B fi'betweien inlet conduit 44 and upper comp rtme t to." fiimilar unde rlying lips Ba, '90. 2 9.3 n i rl de, ott J"- platefil' of the duct spaced above the bolt offthe tank tp proyid'e a similar slotjl'ol a ilert rend :of h a k .1 1 direct ommuni tion" ith outlet conduit -36 Theroverlyingand 4nd i wm f cie y l t a s gas pass therethrough .to sweep alongthebottom of, h 'uppercoinpa'rtmentl. In other words gas going throughjslot 85, lswe'eps along .the ,top of Pi te "l,', ga ;passing' through .s lot 10.0 sweeps a r s i h a e of p t s. Pass g hrou '0 swfeiepspacross theto'p of plate 1], etc.

blowgoe {I [0' is provided along thetop s y m s s I -t se ai W fi, releases, the pressure thus pre nti s qa ag t9 the,.'chambe1'.,, lnlets lfl tlets I '21 connectgthe. side co'mpartments with outlet '36. the side. compartments, are normauy' sealed, from each pthe'r and other qm e tg e t i i g ss r le to eve at 'fthe'iwelded joints, It (is therefore desirahle to have amai'rangement wliicl'i ,w'illpermit, the side 'partments to be cleared ofair and filledlw ith as; aswelias to [equalize the pressures 1 nsbm r en U ,(flhe apparatus may. be, ,operated lras follows: After chamber; or tank as well. ast'he entire co ifihed main circulatorysystem, is filledwith i sas, .for1 example, as described in i sffi nfi sas i uousseru e ffi i z rsss e, erh netm ph ric'is assedlthrough the system, including inletl Icon ui t", 3'0, upper compartment. f 50, and outletllconduit at mhsi iscu nbn is obtained byfthefuse of blower T 3 8 the suction ,side of which cpnnectsgfthe outlet side of the chamber, Inlet sensors; 32 "closedfand atomizer 2.2 is not in operation; lwithiatgomizer 12D operation a-. fine eem o a 'e si4 m is v ihe i it-spl i' QSL att m Z h "me The atomized metal' is promptlg feniiloped and frogen into powder particles in the relatively lcool inert gas, sweeping through. the, upper .compart m g While i ssn a We d ass s of; ma netWtPQW Jfi Q-iq emai suspension lathe ect 3 conduit 4?! .with sthe Iside compartments and lower compartment or-duct 52 substantially exceeds that entering by way of inlet 30. Some of the gas from inlet 44' issues as a relatively small stream through slot 86, the stream being directed along the top of plate 18 at the bottom of the trough. Any magnesium powdersettling or tending to settle on that plate is, therefore, swept up and placed in suspension in the main and large current of gas passing through the upper compartment. In a similar manner gas in the lower compartment or duct passes as a stream through slot I00 along the top of plate H at the bottom of the trough of the upper compartment. Similar streams of gas pass through slots to I06, so that plates E6, 75, 14, 13, I2 and H at the bottom of the trough of the upper compartment are continuously swept with streams of gas under sufilcient velocity to keep the powder from settling and to keep it in suspension. An additional stream of inert gas passes through duct I01 into the discharge end of the upper compartment. Some of the gas thus introduced through the slots also spreads to the side and sweeps across plates 5| to 68 to keep them clean of powder. The mixture of gas and powder is under a great deal of turbulence which inhibits settling of. the powder. The powder laden gas is in effect sucked from the upper compartment by the blower and blown to gas-powder separators (not shown), where the powder is recovered. If the molten magnesium is to be atomized at the other end of the chamber, or tank, inlet conduit 30 and atomizer are not in operation. A fine stream of molten magnesium issuing from the nozzle of atomizer 22 is blasted with inert gas and the atomized metal is promptly enveloped in the relatively cool inert gas entering the upper compartment by way of inlet conduit 32. The force behind the fine stream of molten metal issuing from the nozzle of the atomizer and the force of the inert gas used to atomize the stream of molten metal is sufiicient to throw the atomized metal substantially across the length of the chamber. Additional amounts of inert gas are fed into the upper compartment, as just described, through ducts 86 and I00 to I01.

While various inert or non-reactive gases may be employed, helium is at present the most readily available. The method and apparatus may be used to produce various metal powders, either in elemental or alloy form. They are at present being used to produce magnesium powder and also magnesium-aluminum alloy powders.

It will be clear to those skilled in this art that the method and apparatus of the invention readily lend themselves to various useful modifications. The chamber or tank can, for ;example, be placed in numerous positions, horizontal, inclined, or vertical. The chambercan be arranged in any suitable form. Various arrangements are possible for introducing the additional amount of inert gas to the atomizing and powderforming zone. Whatever the particular arrangement selected, the newly formed particles of metal powder are kept in suspension so that pow- 6 der laden gas may be promptly and emciently and continuously removed from the chamber.

I claim:

1. In the method of producing metal powder by atomizing molten metal with a blast of gas inert to the metal and freezing the atomized metal into finely divided particles in a zone forming a part of a main. circulatory system, the improvementwhich comprises conducting the molten metal atomizing and metal powder forming steps in a main streamvof the inert gas moving continuously from the main circulatory system through the zone, the gas being under sufficient pressure higher than atmospheric to prevent ingress of outside. air and sufficiently cool to chill the atomizing metal into powder particles, introducin into the zon continuously an auxiliary stream of inert gas from the main circulatory system to help keep the newly formed metal powder in suspension in the zone, and withdrawing the metal powder continuously while still suspended in the main stream of inert gas leaving the zone.

2. Method according to claim 1, in which the auxiliary stream of inert gas from the main circulatory system is fed into the lowermost portion of the zone to help keep the powder particles in suspension in the gas passing through the zone. 7 7 3. Method according. to claim 1, in which spaced auxiliary streams of the inert gas from the main circulatory system are passed into the lowermost portion of the zone to help keep the powder particles in suspension in the gas passing through the zone.

4.. Method according to claim 1, in which spaced auxiliary streams of the inert gas from the main circulatory system are passed into the zone in the general direction of travel of the gas in the zone to help keep the powder particles in suspension in the gas passing through the zone.

5. Method according to claim 1, in which Spaced auxiliary streams of the inert gas from the main circulatory system are passedinto the zone in the general direction of travel of the gas so that the streams of gas tend to sweep along the bottom portions of the zone between adjacent streams to help keep the bottom of the zone free of precipitated-metal powder and to keep the powder in suspension in the gas passing through the zone.

6. Method according to claim 1, in which the zone is elongated with inert gas entering at one end and gas from the main circulatory system laden with metal powder leaving at the other end, and spaced auxiliary streams of the inert gas are passed into the bottom of the elongated zone, the

entrance of the streams being spaced from one another in the general elongated direction of travel of the gas in the zone so that the streams of gas tend to sweep along the bottom portions of the zone between adjacent stream entrances to help keep the bottom of the zone free of precipitated metal powder and to keep the powder in suspension in the gas passing through the zone.

7. In apparatus for producing metal powder by atomizing molten metal with a blast of gas inert to the metaland freezing the atomized metal into finely divided particles in a chamber forming part of a main circulatory system, the

improvement comprising an inlet in the chamber connecting the main circulatory system for the entrance of a continuous main stream of the inert gas and an outlet in the chamber connectingthe main circulatory system for the continuamass? oils withdrawal -.oi the main streams of -th-e gas with 'rthe newly formed. metal powder sparticles suspended therein and a separate inlet connecting -.the maincirculatory =system with the chamberr-for introducing .an-auxiliary streamof inert 6 gas. from the main circulatory systemto help keep the newly formed-powder particles sus pended-inv themainstream of inert gas- -passing through the-chamber. 8.rApparatus according to claim 7', in which 10 the separate inlet is provided at the bottom of the chamber for the injection-ofthe auxiliary stream of inertlgas into the'lowe-rmost portion of the ,chamberl to help keep the powder particles insuspensionin the main stream of gas passing through the chamber.

z 9. Apparatusaccording tooolaim 7-, in--which spaced openingsare provideduat the bottom of the. chamber "for; the injection of -spacedstreams of additional inert gas from the. main circulatory system intozthelowermost portion of the chamber to helpkeep :the powder particles in suspension in the gas passing through-the chamber.

l0.; Appara tus-according to claim 7, in-which spaced openings are provided at the bottom of an;, elongatedmphamber, the openings being spacediirom t ne-another and. .directed'in the general direction of travel of the current oi gas through the chamber so that the streams of; additional gas injected. through the openings into the chamber tend-tosv eep-along the bottom portions to help keep theibottom freeoi precipitated m etal powder andeto. keep thejpowder in suspension in the gas passin-glthrough the chamber.

3L Apparatus according to, claim 7., in which. the chamber; isdivided into an upper comparte ment for the atomizing and powder forming steps and-a lower compartment forflsupplyingu the additional gas to the upper1compa-rtment;.. the upper compartment is provided with said first mentioned inlet and outletpthe lower com partment is provided with: a separate, inlet for the,,entrance of;.th e auxiliary streampf gas; and 5 apluralityof spaced openings are-disposed be-; tween the top of the lower compartment and the-:bottom, cf the upper compartment for the passage ,of a; plurality of streams of thegas from he l w r to th ,v unn r mpartment to; he p a so: keep the powder particles in suspensionin the" mainstream of gas passing through the upper compartment.

. lZMApparatus according to claim '7; in svhich thech'amber is divided into an upper pompart-i ment for the atomizing and powder-- io rming steps and .a lower compartment ior supplying additional gas to the upper compartment; the: upper compartmentois provided with said first: mentioned inlet and outlet; the lower; compar.t. mentisprovided with-the separate inlet- ;for the entrance of the auxiliary streamoi gas; and a plurality of spacerlgopenings are;dispo sed be-;; tween the, topoithelower compartment and the. bottom of the -1Dper .,-c0mpartment for the pa 05. sage of a plurality of streams of the gas from the lower to the upper compartment; said open-1 ings being spacedfrom one another in the gen-;. eral. direction-of travel of the gas ,in its upper. compartment. between the inlet and-outlet -;s0; that the. streams of gas pas in zthr ueh th openings help, keep the powder particles in sus-. pe si n in the t espassin thr h the-upp compartment. 2

epparatus-accordmglto I claim 7. 1m which; is

the chamberis-elongated-; the chamber is divided into anelongated uppercompartment for theatomizing and powder forming steps and an elongated lower compartment .for supplying additional gas-to the upper -compartment; the upper compartment-is provided with said first mentioned inlet-andoutlet at opposite ends; the lower. compartment is provided with the separate; inlet for the entranceof the auxiliary streamwf gas; and'aplurality of spaced openings aredisposed between the top of' the lower compartment and the bottom of the upper compartment :ior the-passage ofa plurality of streams .of-l the: gas from the lower to the upper compartment; said jopenings beingspaced from one :zanother in thegenerab direction of travel of thegas in the-upper compartment'between its inlet and outlet so thatthe: streams of gas passing. .through' the openings: help keep the powderiparticles in q-suspension the gas passingv through the upper-compartment.

14p Apparatus according. tovclaim '7, in which thepchamber; is: divided into an vupper compartment for the .atomizing and powder forming steps and .a lower. compartmentfor supplying additional *gas to vthe; upper compartment; the upper compartment-is provided with said first mentioned inlet and outlet; the lower: compartment is providedwith the separate inletdor the entrance of thenauxiliary;stream:of gas; and a plurality :of spaced openings arehdisposed between the top of vthe-lowercompartment and the; bottom of the; upperncompartmentfor the passage ofzapluralityof streams of, the gas from thelower tothe uppercompartment; said openings extending in-the general;=.direction of travel of the gas in the upper .compartmentxbetween its. inlet andy-theoutlet'so that; the streams of gas-passing throughthe openings tend to sweep along thmbottommortions;of .the. upper compartment between adjacent 1 openings to help keepthe bottom-free of; precipitated metal powder and to keemthe 'pflwderwin suspension in the gas passing through the upper. compartment.

-15. Apparatus according toiclaim 7, in which the chamber is elongated;,;the.;chamber is divided, into an upper elongatedcom-partment for t a Om andipowder:formingzsteps and a lower elongated p'compartment .ior supplying additional gas; to the upper compartment; .the upperrre-compartment is; provided with said first mentioned inlet andgoutletr atopposite ends; the lower compartmentis provided with the separate, inlet. for thewentrance Ofua, continuous current'of gas; and aplurality' ofispaced openings r are e disposed between the :top'xof the lower compartment andtherpottom of the upper .compartment for the -p assage of. a: plurality of streamsqof thegas from the lower-to .theupp compartment; said openings, being spaced A from one another in thegeneral elongated direction of travel of the-gas in the upperqcompartment betweenjts inlet and outlet; so that the streams of gas passing through .the openings will tend to swe'ep along thebottomportions .of the upper compartment between adjacent openings to help keep the bottom'portions free of precipitated-metal powder andto keep thespowder in suspensionin the gas passing through the uppencompartment.

-.'.l6.-In apparatus for producing metal powder by atomizingumoltenmetal with a* blast of gas and freezing ,thelatomized metal into finely; divided particles.irraphamber, the improvement comprising an elongatedechambensubstantially the same in cross section throughout its length, the

chamber being divided into an upper elongated compartment for the atomizing and powder forming steps and a lower elongated compartment for supplying additional gas to the upper compartment, an inlet at one end of the upper compartment for the entrance of a continuous current of gas and an outlet at the other end of the upper compartment for the continuous withdrawal of the gas with the newly formed metal powder particles suspended therein, the upper compartment taperin from the inlet end to the outlet end with the largest cross section at the inlet end and the smallest cross section at the outlet end, an inlet in the lower compartment for the entrance of a continuous current of gas, the lower compartment tapering in a reverse direction from that of the upper compartment with its largest cross section opposite the inlet end of the upper compartment and its smallest cross section opposite the outlet end of the upper compartment, and a plurality of spaced openings disposed between the top of the lower compartment and the bottom of the upper compartment for the passage of a plurality of streams of the gas from the lower to the upper compartment, said openings being spaced from one another in the general direction of travel of the gas in the upper compartment between its inlet and outlet so that the streams of gas passing through the openings help keep the powder particles in suspension in the gas passing through the upper compartment.

17. Apparatus according to claim 16, in which the upper compartment is in the form of a trough and the spaced openings are in the bottom of the trough.

18. Apparatus according to claim 16, in which the openings are spaced from one another in the general elongated direction of travel of the gas in the upper compartment between its inlet and outlet so that the streams of gas passing through the openings will tend to sweep along the bottom portions of the upper compartment between the adjacent openings to help keep the bottom portions free of precipitated metal powder and to keep the powder in suspension in the gas passing through the upper compartment.

19. Apparatus according to the preceding claim, in which the upper compartment is in the form of a trough and the spaced openings are in the bottom of the trough.

HENRY A. GOLWYNNE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,156,079 Holley Oct, 12, 1915 2,255,227 Parsons Sept. 9, 1941 2,402,441 Paddle June 18, 1946