CA1106600A - Gas-dynamic stirring of liquid molten metals - Google Patents
Gas-dynamic stirring of liquid molten metalsInfo
- Publication number
- CA1106600A CA1106600A CA307,895A CA307895A CA1106600A CA 1106600 A CA1106600 A CA 1106600A CA 307895 A CA307895 A CA 307895A CA 1106600 A CA1106600 A CA 1106600A
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- CA
- Canada
- Prior art keywords
- gas
- tube
- metal
- pump
- compressed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D27/00—Stirring devices for molten material
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B21/00—Obtaining aluminium
- C22B21/0084—Obtaining aluminium melting and handling molten aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
- C22B9/02—Refining by liquating, filtering, centrifuging, distilling, or supersonic wave action including acoustic waves
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- General Engineering & Computer Science (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
- Mixers With Rotating Receptacles And Mixers With Vibration Mechanisms (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An apparatus for gas-dynamic stirring of molten liquid metals including a pump and molten metal bath, com-prising: a tube with a removable cover; a system for supply-ing compressed-gas pulses, including an outlet nozzle, a pres-surized-gas accumulator and a gas-distributing device, a suc-tion system for withdrawing a metal portion into the tube of the pump, including a suction cut-off device; a sensor of the metal level in the molten metal bath, the outlet nozzle being directed upwardly toward the cover of the tube of the pump and encompassed in a movable annular sleeve with a shoulder, the cover having mounted therein rod-type valves adapted to cooperate with the shoulder of the movable sleeve, to communi-cate the internal space of the tube with the ambient atmosphere upon the valves being raised by the action of the movable sleeve operatively connected with a float submerged in the molten metal. Also disclosed is a method based on the use of the apparatus.
An apparatus for gas-dynamic stirring of molten liquid metals including a pump and molten metal bath, com-prising: a tube with a removable cover; a system for supply-ing compressed-gas pulses, including an outlet nozzle, a pres-surized-gas accumulator and a gas-distributing device, a suc-tion system for withdrawing a metal portion into the tube of the pump, including a suction cut-off device; a sensor of the metal level in the molten metal bath, the outlet nozzle being directed upwardly toward the cover of the tube of the pump and encompassed in a movable annular sleeve with a shoulder, the cover having mounted therein rod-type valves adapted to cooperate with the shoulder of the movable sleeve, to communi-cate the internal space of the tube with the ambient atmosphere upon the valves being raised by the action of the movable sleeve operatively connected with a float submerged in the molten metal. Also disclosed is a method based on the use of the apparatus.
Description
The present invention relates to the metallur~ical i-~dus-tr~, and more particularly it relates to metnods of stir~ir~g liquid metals being molten directly in the metal baths ol ~e~ -ing furnaces, which stirring ~ore often than not speeds ~p tre melting process, promotes the homo~reneity of the chemical com-position ol the molten metal body and enhances a uniform t~mpe-rature field of this molten met~l body~
At present, there are already known methods of stirring liquid metals directl~ in the bath of a melting furnace, viz.
the ~echanical method, the electromagnetic method, the gas--dynamic method and others. ~he present invsntion relates to the most simple and promising one of these methods, na~ely, the method of gas-d~namic stirring of liquid metals, particu-larly such corrosive ones as aluminum alloys and the like.
This known per se general method, although ~ielding definite advantages in the productivity o~ the melting process, is not free from serious drawbacks. ~he permanent time interval between the co~pressed-gas pulses acting upon a metal portion in the tube, which may be the optimum one for one of ~he stages, is not, however, the optimum one for the two other stages.
Moreover, the energ~ of the compressed gas is~ ar no~
completely employed for the acceleration of the ~etal in the tube to the re~uired speed. This is explained by the fact that the considerable part of the energ~ of a compressed-gas pulse ~-is spent on arresting the metal in the tube within the period of withdrawinæ it from the hath~ A portion of this energy is spent directl~ on arresting the metal, while the o~her portion , 6~
is spent on cut'cing off the suction from the ~,Jork ng space of the pu~p; and it is onl~ the rest of the ener~rg cf the pulse which is used ~o accelera~e the metal to a certain speed~
Obviously, more often than not it is practically impossible to attain the r~uired sp~ed of the outflow of the metal fro~
the tube, this speed being, however, essential for the effecti-veness of the stlrring of the metal. On the other hand, it is not altogether advisable to follow the path of increasing the initial energ~ of a compressed-gas pulse, since the counter--action of the metal risin~ in the tube and of the compressed--gas flow arre~ting the progress o~ the metal results, as a rule, in a certain degree of gas saturation of the ~etal.
Thus, if the pulse energy is stepped up, it is guite natural ~o expect that the ga~ content in the metal would grow, which is undesir~bleO
~ he pre~ent invention is ai~ed at intensif~ing the pro-cess of stirring molten metal, e.g. of ~olten aluminum and its alloys in combustion rev2rberator~ ~u~lnaces of a great capacity, particularl~ those of a rectangular cross-section, wherein the depth of the ~ody of the molte~ metal is a fraction of the length of the ~urnace.
There are known a. method and an apparatus for stirring molten metal, disclosed in th~ US Patent ~o. 4,008,884;
US Cl. 266-233; Int.Cl.2 C 2Z ~ 9/02, file~ June 17, 1976, by ~igel Patrick Fitzpatrick~ Jame~ Ne~ille Byrnl et al.~ assig-~ors to Alcan Research and Develop~ent ~imlted, Montreal, Canada .
This molten metal stirring method includes alter~atingl~
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, thdrawing ~oltcn metal from ~he molten mletal GGd~ ir'co Si confined spac~, e.g. a tubular vessel1 to a cer-t~in level above ~he molten metal body in the bath, and e-~pellin~ tr.e wit~ldrawn moltel metal into the molten ~etal bod~ as a s~b~e -ged high-velocity je', for stirring the ~etal body, the sub-merged jet being directed horizontall~ within the lower par~
of the metal body, to a distan~e substantiall~ in excess o the depth of this body.
In accordance with this known method, the alternating withdrawing and expelling s-tage~ are effectuated by ~upplyinG
suction and pres~urized gaseous fluid into the confined space above the molten met~l body (i.e. into the top part of the tubular vessel), the withdrawing of the liguid metal being effected through an orifice of this ves~el at a lower part of the molten metal body, and the expelling of the submer~ed jet taking place horizontally in the lower area of the metal body.
~ he method is further b~sed on each suction stage inclu-ding feeding out a suction isignal upon measuring the suction value in the top portion o~ the vessel and monitoring the duration of the suction ~tep in accordance with the suction value being maintained at a preset level, communicating the suction to raise the molten metal in th~ vessel, determining the level of the rising metal and terminating the suction supply upon the metal having risen to the predetermined level~
In accordance with the disclo~ure in the abo~ementioned US Patent ~o. 4,008,884, the apparatus for stixri~ molten mstal include~ a tubul~r vessel having at the lower extremit~
thereof a noz~le su~merged into the molten metal bod~, the , ~ _ 4 _ --6~
upper extremity of the tubular vessel having a device (of the aspiration type) for alternatingly withdrawing metal (by suc-tion) into said vessel to a specified level above the molten metal body and expelling the withdrawn metal into the molten metal body via the nozzle under the action of the gaseous fluid. This gaseous fluid, i.e. air is supplied from a receiver into the aspiration device via charging and discharging solenoid valves.
The se~uence of the charging and discharging operations is controlled by a vacuum switch and an electric timer. To preset the maximum premissible level of the raising of the molten metal, the internal space of the tubular vessel receives therein an electric level sensor connected with a switch-off relay n However, the known method described above and apparatus for gas-dynamic stirring of liquid molten metals suffer from disadvantages which to a certain degree curb down their wider application.
The stationary arrangement of the tube of the pump in the bath of the furnace provides for active stirring within a limited area, which means that furnaces of great capacities re~uire a plurality of such pumping arrangements.
When metal is molten in furnaces of eitner circular or square shape, even those of relatively small capacities, at least two pumps are to be installed to attain adequately swift melting and dissolving of the alloying additives. On the other hand, the arrangement of a plurality of the pumps on a melting furnace is often associated with difficulties~
' vo say ,~thin~ of -the i~creased CGnsu~n?tion 5L' CO.r~ip-'r-S'- ed air, T~rle withdra~ral or ex~elling of the ~e'tal av a ce~iri~, ri~cd height ebove the hearth of the furnace is i;-l vhe ,;e7 of employing to the fulles-' poss~ble degree the broed ca~,2-bilities of the method being discussed, ~rom the point of view of the provision of the optimum condi-tions for ~eat and. mass e~{chun~e. ~his drawback becomes particularly prono~ln-ced in the ca~e of the melting of solid charge, when t~e temp2ratllre of the molten metal is still relatively lo~l, and the washing over of the solid lumps of the charge with the relatively low-temperature ~etal jet would not yield the op-timum outcome, as far as the melting rate and the utilization of the heat in the furnace are con-~erned.
In furnaces with ~ol-ten metal bodies of a considerable depth the hitherto known method likewise would not ~ield the best resul-ts. In this case it is relatively difficult to se-lect the optimum arrangement of the pumps verticall~ of the molten metal body~ with the latter's le~el being variable within a relativel~ broad range.
~ urthermore, the energy of the compressed-g0s pulse is not utilized to the full capacity, with the compressed gas.commencing its action upon either rising, or, in the best case, stationary portion of the liquid ~etal in the ~ube of the pump. This would not ena~le to attain the maximum speeds of the jet of the metal issuing from the tube of the pump for a given gas pressure. With the gas pressure being stepped up, the energy cost factor rises accordingly, with the condition~ being created for an increased gas content in the -~leca I~he operatiori at a preset vacuum or suc~iO;~ alue ccn-trolled b~ the suction switch for each incividu~' ~)ump ~rould not enable to s.eed up noticeabl~ the withdra"al OI a metal portion in-to the tube of the pump, i.e. to cut ~he time of the wil.hdra~J~l s-tep. Moreover, the creation of the suc~ion b-~ the aspiration device molmted on the pump and put into action only f`ollo~ing the termination of the supplying of ~he compressed-gas pulse via the respective solenoid-^ontrolled valve obviously increases the time of withdrawing metal into the tube. In this case, too t there no efficient ~Jay of speea-ing up the withdrawal of the metal into -the tube of the pump.
~he two last-discussed factors affect the efficiency o~ the operation of the pump, particularly, at the stage of melting soli~ charge, when the increased frequency of the alternation of the withdrawal-expelling c~cles is required.
It is the main object of the present invention to c~eate a method and apparatus for gas-dg~amic stirring of molten liquid metals, which should enhance the efficienc~ of stirring liquid metals in high-capacit~ furnaces and ~hould eliminate the drawbacks of the hitherto known methods and apparat.us used for the same purpose~
It is a not less important of -the present invention to create a method of gas-d~namic stirring of liguid molten metals, which should of`fer more economical and full utilization of the ener~ of the compressed gas.
It is an object of the ~resent in~ention to provide a method of ~as-d~namic s-tirring of liquid molte~ ~etals~
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hich should enhance thG ~etal gu21i~y ~ re~ucin~ -the gas conten-t therein~
It is a further object of the present invention to cre~te an apparatus l`or gas-dynamic stirring, capable o~
performing the a~ovemen-tioned method, which should provide for its accessible mouthing on high-capacit~J melting furna-ces without any reconstruction of the latter, and 7,rhich should provide conditions for effective stirring of the metal.
It is a still another object of the present invention to create an apparatus for gas-dynamic stirrin~ of liquid molterl metals, which should provide for reduci~g the gas saturation of the metal while the latter is being expelled.
These and other objects are at~ained in the herein ais-closed ~ethod of gas-dynamic stirring of, liquid molten metals, including alternatingl~ withdrawing portions of the metal from the molten body into the tube of the pump by the use of suction and expelling these portions of the metal back into the molten body by acting thereupon b~ compressed-gas pulses, in which method, in accordance with the present invention, directl~
prior to the suppl~ing of said compressed-gas pulse into the ~ube of the pump, the action of the suction i~ terminated, to provide for free descent of the raised metal portion b~ gra-~ity.
~ his technical solution enables to step up the effecti-veness of stirring molten metals in high-capacit~ for accelera-ting metal portions bein~ expelled into the metal body to higher speed~ with the compressed-gas pulse acting upon . , , $;~
the ~ithdr~rQ r~ tal po~"tion ~rhicn has alread-J be~u-r. its ~-^env under the gravity forces. I~ this case t.qe enti e ener~J o~
the compressed-gas pulse is spen-t on accelera~ing the me~l portion already ;~aving some initial speed, T~hich eventuail~
resul~s in the higher speed of the exit of the ~etal jet from thc ~ump tube, and, hence, in a longer path of t~.is jet ithin the molten metal bod~, which is essential for high-capacitJ
plants. ~he action of the compressed~gas pump upon the retreatin~ -metal hampers the conditions o~ saturating the metal witn the gas , as compared with their motion against each other~
It is expedient that prior to suppl~ing said compressed--~as pulse to expel the withdrawn metal portion from the tube, the space in the tube of the pump above the metal portion -should be communicated to the ambient atmosphere.
~ he above feature provides for a more economical use of the compressed-gas energ~, owing to the arresting and preacceleration of the withdrawn metal portion being effect-ed by the energy of the a~bient atmosphere, with the metal being preaccelerated in this case b~ gravity alone. The energy of the compressed-gas pulse is then entirel~ spent on the acceleration o~ the alread~ moving metal portion in the tube, which enables to step up the speed of the exit of the metal jet from the tube, to prolong the path of the jet within the molten metal bod~ and to intensif~ the stirring process.
It is further expedient that the said compressed-gas pulse be timed with the commencing of the free gravity descent of the -~etal portion.
~ his feature enables to utilize the energ~ of the comp-- 9 ~
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, .r-~ssed ~as -o thC .lig~he t ~egree, c~;rin~ to the cc~-~rresce~ g-_ r-trea~. ~assing h~ minimuT~ necessa~ pa-t~ bO e;ecV~ er v`^l-liquid me~al in he t~be, which nas alreaay beg~ its dr-sce tS
so that i-~ e~ti~e energ~ is spent on accele~ating the .~.~era It is still further e~pcdient to perform vhe herein clisclosed method of gas-dynamic stirring of molten liq~id metals in an appa~atus co~prising a -tube with a re~lovable cover, a system ~`or s~pplying a pulse of compressed gas from a pressure accumulator via a dist.ributor into the outlet nozzle, a suction system for withdrawing metal portions, including a suction cut~off device, and a sensor of the metsl level in the molten metal bath,in which apparatus, in accordance with the present invention, the outlet no~zle is di.rected upwardly to-~rard the cover of the tube of the pu~p and is received within a movable annular sleeve ~rith a shoulder, the cover having ~oun-ted therein rod-type valves cooperating with said shoulder of the movable sleeve to communicate the internal space of the tube with the ambient atmosphere, upon the valves being raised by the movable sleeve, the latter being ope.rativel~ connected with a float submerged in the body of the raising metal portion.
The apparatus of this kind enables to mount the pump on -~
a hi~h-capacity melting furnace without the necessity of re-constructing the latter, and to provide the prerequisi~es for efficient stirring, owing to the device for communicating the internal space of the pump ~rith the ambient atmosphere being accom~odated within said space and emplo~ing for open-in~ ~ne communication the ener~y of the metai portion ascend-ing in the tube. ~he operative connection of this device with ~ 10 -.
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-~-he rr.e ~al via ~re float ensures tnat the i~l'cer~lal ,pa!e of t~-pump is co~mur~icated ~sith the am~Dien-t atr"lospnere ~aca succe~
ve c~cle of withdra~ing a metal portion into t~e tube, a.~d, consequently, provides the necessar~ prerequisites for a~vain-in~ a high speed of the exit of the metal jet fro-~ ~he tube, hen the oncoming compressed-gas pulse acts thereupon.
It is ex~edient, that said cover of the pump be provided OIl the in~ernal side thereo~ with a tapering dissector of ~he gas stream~ arran~ed axially o~ the outlet nozzle and merging wi-th an annular toroidal cavity having said rod-type valves arran-ged in the indentation thereof~
~ his feature enables to create conditions for reducing the gas saturation of the metal being expelled b~ the action of the compressed-gas pulse thereupon, owing to the compressed--~as stream being dissecte~ and uniformly distributed over the entire cross section of the tube of the pump.
It is further expedient that the float be connected with the ~ovable annular sleeve with aid of links of adjust-able len~th, interconnected through detachment assemblies.
~ his feature enables to conduct the operation of the pump at dif'ferent rates of the ascent of withdrawn metal por-tions in the tube, b~ ad7ustin~ the spacing between the float and the sleeve and by selectlng their optimum relative posi-tions in accordance with the ascent rate. Moreover, ~rovision is made for replacin~ the float and the sleeve, whenever ne-cessary.
It is further e~pedient that the cover of the tub~
of the pump should have mounted therein an electric contact ,~ - '11 -., . ~ .
~e~ice -n the LOL'~ Oi ~ probe wired i~to ~Lhe ciro~i J cc.r.'c'~o7-, the suppl~fi~g of compressed-gas pulse~, the ~ g-t`rl G~
~his probe wi~hin tne internal space of ~he tu~De beilng sel~c-tea so thev tre ti,me o~ the passage of -the wit'ndra1,.Tn mev~l pG ~ -tion along the probe up to the moment of the raisi~g of the rod-type valves should be in excess of the time of the respor.se of said system for supplying a compressed-gas pulse.
~ his feature enables to speed up the rate of the ascent of the metal in the tube of the pump, owing to the possibility of operating a~ suction values whereat the metal could have been theoretically raised above the cover of the pump~ In trlis case it is feasible, and that without any additional monitoring and control means, to time the commencing of a compressed-~as pulse with the commencing of the gravity descent of the metal portion.
It is still further expedient that the said probe of the electric contact device be mounted in the cover ~f the tube of the pump in a collet chuck providing for the advustment of the axial protrusion o~ this probe, ~ his feature enables to adjust the extent of the ascent of the metal along the probe, and, hence to time accurately the co~mencing of a compressed-gas pulse with the commencing of the gravity descent of the metal portion.
Xt is further expedient that said outlet nozzle should have at the inlet thereof the said suction cut-off device, connected in parallel with the system L or withdrawing metal portions by suction and with the syste~ for supplying compres-sed-gas pulses, the suction cut~off device including a movable - . ' .' ' ~
, r~
nozzle r~ounted a~ a v~lve mcmber in anGthcr outer cor.icsl nozzle a~d ~Gvable relative ~o the latter b~ a s~ing of ~rhich the efior~ is adjusted to close off the flow ~assage arld to set orle nozzle into the other one, as a co~pressed--~as pulse is supplied.
~ his feature enables to eliminate the influence of the suction syste~ on the conditions created for timing the co~en-cing of the co~pressed-gas pulse with the commencing of the gravit~ descent of the metal portion, owing to the vacuum or suction system becoming disconnected from the internal space of the tube of the pump at the supplying of the compressed-gas pulse and not inter~ering with the commencing of this gravity descent of the metal in the tube~ ~he feature also facilitates the corresponding adjustment of the precise ti~ing of the two operations.
~ urther~re, the last described feature enables to speed up the action of the apparatus, and, hence, the productivit~
of the pump, owing to neither specific equipment nor corres-ponding time being reguired for connecting the suction s~stem to the internal space of the tube of the pump upon the termi-nation of the action of a co~pressed~gas pulse. The frequency of the cycles~ on the other hand, is in this case readily adjustable by incorporating and adjustment throttle governing the rate of the building up o~ suction in the tube, and, conse-quently, the rate of the withdrawa~ of a metal portion from the metal molten body.
The present invention will be further described in con-- 13 ~
, ' ' 'lCC '-ion w -th i-t~ preferreà embcdiment ir. t~le follG~ .g da-,ai~a~
desc~ tion thereo~ ith reference bein~ made ~o tha accGmpa.
ii.g dra~Tings, w~arein:
lIG. 1 illus-trates schematically the state of a ~rit'~dra~,.r metal portion in the tube of the pump;
~ 'IG~ 2 is a chart OI variation of the speed of ~he ~otio-,~
of the metal portion bein~ returned into the molten metal bod~, versus time;
~ IG~ 3 is a longitudinal sectional view of the stirring apparatus, with tha control system shown schematically;
~ IG. 4 is a sectional view of the end portion of the tuhe associated with the valve in the apparatus illustrated in ~IG. 3, at the time of the suppl~ of a compressed-gas pulse;
~ IG, 5 is a sectional view of the end portion of the tube associated wi-th the valve in the apparatus illustrated in FIG. 3, when the interior of the tube com~unicates with the ambient atmosphere;
~ IG. 6 is a diagram of the control s~stem of the suppl~
of compressed~gas pulses i~ the apparatus illustrated in G. 3;
~ IG. 7 illustrates the mounting of the electric contact device - the probe ~ on the cover in the apparatus illustrated in ~IG. ~, ~ -LG. 8 illustrates the suction cut-off device of the app~ratus shown in ~IG. 3.
~ he conductin~ of the gas-d~namic stirring procass in accordance with the disclosed method i.s schematicall~ illustra-ted in the appended drawings, ~igs. 1 and 2, wherein there :
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~ , . ' v is shown the c~Jcie diagra~n of 'che opera tion O t,~4e pvmp, 7-lated to the p-rogress of the metal in the tube oP the ~u~p, CO7-responding to each successive step of the opera~ing cycle o~
the pump~ where V iS the rate of thè progress of metal in the tube,lJi~.
the "~" and tt_ll signs desig~ating, respectively, ascent and dcscent;
~ is ti~e;
P1 and P2 are the pressure values, correspondir.g,respec-tively, to the main pulse /1/ and auxiliar~ pulse /2/. - -'l'he ~ash line irl tle al~win~ illustrates for comparison the acceleration of metal in the tube in accordance with the met~od of the prior art~
~ rom the ~etal body in the bath 1, e~g~ of a melting furnace, there is ~Jithdrawn into the tu~e of a gas-d~namic pump ~ a metal portion 3 (of a preset volume) at a certain ra~e ~V, b~ suction in the working space 4 of the tube.
~ hen the metal portion in the tube is acted upon b~ an auxiliary pulse of a compressed gas at a pressure P2, e.g. air under atmospheric pressure, with the suction supply being simultaneously cut off from the working interior of the tube of the pump. Owing to this, the rate of ascent of the metal drops -to zero, so that the metal halts in the tube at a certain preset level, ~Jhereafter it starts descending in the tube~ i.e.
acguires an initial rate of the motion in the opposite direc-tion. At this moment a co~trol signal~ i.e~ one sent b~ a cor.tact-type level sensor~ initiates the supplying of the main compressed gas pulse, which accelerates the met~l in the - ' ,. : ~ .
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tube to a ~i~re~ s~d. 'nhG rletal jet issu~ at ~ni~ e~ i-i~c the ~,~olten metal body, enga~in~ the adjacent me~al la~elc a~~
thus agita-ting the metal throughout -the l~olume of ~he -~olten bod~J O
~ onducting the herein disclosed method with the timed feed o~ the two pulses is possible with either manual control from a control panel, or fro~ a control co~puter, with aid of a specific device for cutting off the suction supply and commencing simultaneously the suppl~ of the auxiliary pul~e at a pressure precluding the saturation of the metal in the tube with ~as. It is expedient to conduct the herein disclosed method with the auxiliary pulse being followed b~ the ~ain pulse with a delay egualling the time of passage of the control action through the system.
Given hereinbelow is an exa~ple of employing the herein disclosed method at the melting of alu~inum alloy, with the molten metal body being stirred at every melting stage in a meltin~ furnace of the 30-ton capacity.
~ he gas-d~namic pump was operated with the freguency or rate of the supply of compressed-gas pulses within a range from 4 to 20 pulses per minute. While the metal portion in the tube was accelerated and expelled into the molten metal body, it was successivel~ ac-ted upon by two pulses. ~he first pulse - t-~ie auxiliary o~e - was with aix under the pressure of 1 atmosphere abs., i.e~ under the atmospheric pressure, by simultaneously cutting o~f the suctio~ suppl~ to the worXing space and communicatin~ the latter with the ambient atmosphere.
~his resulted in the rate of ascent of the ~etal in the tube , ' - , , . , , ,:
' d-ro-~pin~ i o~ 1~ m/s (et O,L~ a-tm suctiorl) -tG ~f,rO aLd cha~g Ig to a descent in 0.~ .~. 0.8 second, following -t~e inltia'io. 5-tl~e auxiliary p~essure pulse supply. So, in 0.5 seco~d afte~
t~le initiation of the auxiliar-~ pulse supply the control signal was sent, and in about 0~1 second after that t`ne actuav-in~ T2ember - the distributor - responded, and the main pressure pulse at a 5.0 atm~ pressure accelerated the metal from the initial ra-te o~ 0~5 m/s (following the termination of the action of the auxiliary pulse) to about ~.5 m/s b~ the time of the termination of the action of the main cor~pressed-gas pulse.
~ hus, in the abovedescribed manner there was effectuated the acceleration of metal portions for gas~d~namic stirring at ever~ melting stage, irrespectivel~ of the ratf of the supplying of the pressure pulses, which enabled to cut down the melting time b~ 10%, as compared with the method of the prior art.
~ he abo~edescribed stirring mode was maintained until the mol~e~l ~etal was poured out into the mixer.
r~he above example of conducting the method, quite under-standabl~, doe~ not by far restrict the parameters of the process or preclude other ways of conducting the method as de-fined in the Claims to follow.
~ he herei~ disclosed method, a~ experience shows, enables to step up the ef~ici0nc~ of the stirring and to cut down the melting ti~e b~ as much as 15%.
Indicated with arrows in Fig~ 3, 4 and 5 of the append-ed dra~Jings are the xespective directions of the progress of the metal and of the gas streams. In a preferred embodiment, - .
-the ~u~ --or ga~ JnamiC sti.ring oi liquid ~e~<-ll 5 in vhr-bath Or a furrace 6 includes an interrAall~ lin~d ~u~e 7 wi~h a removable cov~r 8 and a nozzle 9 having i~s outl~t direo~ed toward the cover ~ he nozzle 9 is connected via a line 10 with a d~vic~ 'i1 for cutting oif the vacuum or suction suppl~ fro~ the tube. ~he device 11 is also opera~ivel~
colmected ~ith a distributor controlling the suppl~ing of pulses of compressed gas (nitrogen, argon, etc.) from a pres-sure accumulator 13. ~he pressure accumulator 1~ is of a given appropriate volume, with provisions for adjusting -this volume in accordance with the pressure of the gas, maintained with a pressure regulator 14. ~he intexnal working space of the tube 7 is in permanent communication via the nozzle ~, the line 10 and an injector 11 with a suction line 15 including a controllable throttle 16 which enables to ~overn the rate of ascent of metal in the tube. ~here is a contact sensor (not shown) of the me~al level in the tube, wired to send a control signal to the sole-noid of the distributing valve 12.
The cover 8 is provided with a tapering dissecting element 17 adapted to dissect the stream of the gas, the dissecting els-ment 17 being arranged axially of the nozzle 9 and ~erging with a torodial annular cavit~ 18 intended to st~bilize the gas strea~ in the tube o~ the pumpv ~he nozzle 9 is encompassed b~ an annular sleeve 19 with a shoulder, movable along this nozzle 9~ ~he sleeve 19 abuts against a ring 20 adJustable longitudinall~ of the nozzle, i~ which wa~ the required clear-ance between the sleeve 19 and the cover 8 can be set~ ~he sleeve 1~ is operativel~ connected by adjustaDle-length 1L~ S
21 to a floa~ 22. This connection enables to adjust the spa-cing between the sleeve 19 and the float 22, and thus to time the ~ornent when the sleeve 19 closes away the suctiGn line and co~unicates the workin~ space wi-th the a~bient atmosphere. '~he float 22 is preferably made of a light~eight refractory material, e.g. asbestos-thermosilicate and the li~e, or else it can be a hollow member with the case made of a ~etal insoluble in the alloy being stirred. The float 22 is preferably streamlined to minimize its opposition to the ~as stream. It ma~ have an arcuate ~op, or a truncated bottom; alternativel~, it may be droplet~shaped, conical, etc. ~reel~J suspended fro~
the cover 8 are rod-type valves 23 with dishes 24 adapted to close the passages 25 commu~icating the worXin~ space of the tube 7 with the a~bient atmosphere. In a modification of the apparatus, this communication is not with the ambient air, but with a space ~illed with a gas under gauge pressure below that in the pressure accumulator, to provide a "soft"
pulse.
~he herein disclosed pump operate~$ as follows.
With the metal 5 filling the bath of the furnace 6 to a certai~ level whereat the outlet of the tube 7 is not expo-sed~ the suction li~e 15 is co~nected to the i~texnal working space o~ the tube 7, and the pressure accumulator 13 is connec-ted to a compressed~gas source via the distrib~ti~g device 12 and the pressure re~ulator 14. Simultaneousl~ voltage is sup-plied to the coil of the solenoid of the distributing device 12; the rod o~ the contact ~enæor bein~ lowered to a preselect-ed level, depen~ing on the setting of the throt~le 16 arl~ 'vhexelative posivions of the float 22 and t~e sleeve ~I9.
~ he suction raises the li~uid metal into the tube 7 to a certain height, the float 22 with the sleeve 19 bein~ raised accordingly. Eventially the sleev2 19 raises the rod-type valves
At present, there are already known methods of stirring liquid metals directl~ in the bath of a melting furnace, viz.
the ~echanical method, the electromagnetic method, the gas--dynamic method and others. ~he present invsntion relates to the most simple and promising one of these methods, na~ely, the method of gas-d~namic stirring of liquid metals, particu-larly such corrosive ones as aluminum alloys and the like.
This known per se general method, although ~ielding definite advantages in the productivity o~ the melting process, is not free from serious drawbacks. ~he permanent time interval between the co~pressed-gas pulses acting upon a metal portion in the tube, which may be the optimum one for one of ~he stages, is not, however, the optimum one for the two other stages.
Moreover, the energ~ of the compressed gas is~ ar no~
completely employed for the acceleration of the ~etal in the tube to the re~uired speed. This is explained by the fact that the considerable part of the energ~ of a compressed-gas pulse ~-is spent on arresting the metal in the tube within the period of withdrawinæ it from the hath~ A portion of this energy is spent directl~ on arresting the metal, while the o~her portion , 6~
is spent on cut'cing off the suction from the ~,Jork ng space of the pu~p; and it is onl~ the rest of the ener~rg cf the pulse which is used ~o accelera~e the metal to a certain speed~
Obviously, more often than not it is practically impossible to attain the r~uired sp~ed of the outflow of the metal fro~
the tube, this speed being, however, essential for the effecti-veness of the stlrring of the metal. On the other hand, it is not altogether advisable to follow the path of increasing the initial energ~ of a compressed-gas pulse, since the counter--action of the metal risin~ in the tube and of the compressed--gas flow arre~ting the progress o~ the metal results, as a rule, in a certain degree of gas saturation of the ~etal.
Thus, if the pulse energy is stepped up, it is guite natural ~o expect that the ga~ content in the metal would grow, which is undesir~bleO
~ he pre~ent invention is ai~ed at intensif~ing the pro-cess of stirring molten metal, e.g. of ~olten aluminum and its alloys in combustion rev2rberator~ ~u~lnaces of a great capacity, particularl~ those of a rectangular cross-section, wherein the depth of the ~ody of the molte~ metal is a fraction of the length of the ~urnace.
There are known a. method and an apparatus for stirring molten metal, disclosed in th~ US Patent ~o. 4,008,884;
US Cl. 266-233; Int.Cl.2 C 2Z ~ 9/02, file~ June 17, 1976, by ~igel Patrick Fitzpatrick~ Jame~ Ne~ille Byrnl et al.~ assig-~ors to Alcan Research and Develop~ent ~imlted, Montreal, Canada .
This molten metal stirring method includes alter~atingl~
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, thdrawing ~oltcn metal from ~he molten mletal GGd~ ir'co Si confined spac~, e.g. a tubular vessel1 to a cer-t~in level above ~he molten metal body in the bath, and e-~pellin~ tr.e wit~ldrawn moltel metal into the molten ~etal bod~ as a s~b~e -ged high-velocity je', for stirring the ~etal body, the sub-merged jet being directed horizontall~ within the lower par~
of the metal body, to a distan~e substantiall~ in excess o the depth of this body.
In accordance with this known method, the alternating withdrawing and expelling s-tage~ are effectuated by ~upplyinG
suction and pres~urized gaseous fluid into the confined space above the molten met~l body (i.e. into the top part of the tubular vessel), the withdrawing of the liguid metal being effected through an orifice of this ves~el at a lower part of the molten metal body, and the expelling of the submer~ed jet taking place horizontally in the lower area of the metal body.
~ he method is further b~sed on each suction stage inclu-ding feeding out a suction isignal upon measuring the suction value in the top portion o~ the vessel and monitoring the duration of the suction ~tep in accordance with the suction value being maintained at a preset level, communicating the suction to raise the molten metal in th~ vessel, determining the level of the rising metal and terminating the suction supply upon the metal having risen to the predetermined level~
In accordance with the disclo~ure in the abo~ementioned US Patent ~o. 4,008,884, the apparatus for stixri~ molten mstal include~ a tubul~r vessel having at the lower extremit~
thereof a noz~le su~merged into the molten metal bod~, the , ~ _ 4 _ --6~
upper extremity of the tubular vessel having a device (of the aspiration type) for alternatingly withdrawing metal (by suc-tion) into said vessel to a specified level above the molten metal body and expelling the withdrawn metal into the molten metal body via the nozzle under the action of the gaseous fluid. This gaseous fluid, i.e. air is supplied from a receiver into the aspiration device via charging and discharging solenoid valves.
The se~uence of the charging and discharging operations is controlled by a vacuum switch and an electric timer. To preset the maximum premissible level of the raising of the molten metal, the internal space of the tubular vessel receives therein an electric level sensor connected with a switch-off relay n However, the known method described above and apparatus for gas-dynamic stirring of liquid molten metals suffer from disadvantages which to a certain degree curb down their wider application.
The stationary arrangement of the tube of the pump in the bath of the furnace provides for active stirring within a limited area, which means that furnaces of great capacities re~uire a plurality of such pumping arrangements.
When metal is molten in furnaces of eitner circular or square shape, even those of relatively small capacities, at least two pumps are to be installed to attain adequately swift melting and dissolving of the alloying additives. On the other hand, the arrangement of a plurality of the pumps on a melting furnace is often associated with difficulties~
' vo say ,~thin~ of -the i~creased CGnsu~n?tion 5L' CO.r~ip-'r-S'- ed air, T~rle withdra~ral or ex~elling of the ~e'tal av a ce~iri~, ri~cd height ebove the hearth of the furnace is i;-l vhe ,;e7 of employing to the fulles-' poss~ble degree the broed ca~,2-bilities of the method being discussed, ~rom the point of view of the provision of the optimum condi-tions for ~eat and. mass e~{chun~e. ~his drawback becomes particularly prono~ln-ced in the ca~e of the melting of solid charge, when t~e temp2ratllre of the molten metal is still relatively lo~l, and the washing over of the solid lumps of the charge with the relatively low-temperature ~etal jet would not yield the op-timum outcome, as far as the melting rate and the utilization of the heat in the furnace are con-~erned.
In furnaces with ~ol-ten metal bodies of a considerable depth the hitherto known method likewise would not ~ield the best resul-ts. In this case it is relatively difficult to se-lect the optimum arrangement of the pumps verticall~ of the molten metal body~ with the latter's le~el being variable within a relativel~ broad range.
~ urthermore, the energy of the compressed-g0s pulse is not utilized to the full capacity, with the compressed gas.commencing its action upon either rising, or, in the best case, stationary portion of the liquid ~etal in the ~ube of the pump. This would not ena~le to attain the maximum speeds of the jet of the metal issuing from the tube of the pump for a given gas pressure. With the gas pressure being stepped up, the energy cost factor rises accordingly, with the condition~ being created for an increased gas content in the -~leca I~he operatiori at a preset vacuum or suc~iO;~ alue ccn-trolled b~ the suction switch for each incividu~' ~)ump ~rould not enable to s.eed up noticeabl~ the withdra"al OI a metal portion in-to the tube of the pump, i.e. to cut ~he time of the wil.hdra~J~l s-tep. Moreover, the creation of the suc~ion b-~ the aspiration device molmted on the pump and put into action only f`ollo~ing the termination of the supplying of ~he compressed-gas pulse via the respective solenoid-^ontrolled valve obviously increases the time of withdrawing metal into the tube. In this case, too t there no efficient ~Jay of speea-ing up the withdrawal of the metal into -the tube of the pump.
~he two last-discussed factors affect the efficiency o~ the operation of the pump, particularly, at the stage of melting soli~ charge, when the increased frequency of the alternation of the withdrawal-expelling c~cles is required.
It is the main object of the present invention to c~eate a method and apparatus for gas-dg~amic stirring of molten liquid metals, which should enhance the efficienc~ of stirring liquid metals in high-capacit~ furnaces and ~hould eliminate the drawbacks of the hitherto known methods and apparat.us used for the same purpose~
It is a not less important of -the present invention to create a method of gas-d~namic stirring of liguid molten metals, which should of`fer more economical and full utilization of the ener~ of the compressed gas.
It is an object of the ~resent in~ention to provide a method of ~as-d~namic s-tirring of liquid molte~ ~etals~
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hich should enhance thG ~etal gu21i~y ~ re~ucin~ -the gas conten-t therein~
It is a further object of the present invention to cre~te an apparatus l`or gas-dynamic stirring, capable o~
performing the a~ovemen-tioned method, which should provide for its accessible mouthing on high-capacit~J melting furna-ces without any reconstruction of the latter, and 7,rhich should provide conditions for effective stirring of the metal.
It is a still another object of the present invention to create an apparatus for gas-dynamic stirrin~ of liquid molterl metals, which should provide for reduci~g the gas saturation of the metal while the latter is being expelled.
These and other objects are at~ained in the herein ais-closed ~ethod of gas-dynamic stirring of, liquid molten metals, including alternatingl~ withdrawing portions of the metal from the molten body into the tube of the pump by the use of suction and expelling these portions of the metal back into the molten body by acting thereupon b~ compressed-gas pulses, in which method, in accordance with the present invention, directl~
prior to the suppl~ing of said compressed-gas pulse into the ~ube of the pump, the action of the suction i~ terminated, to provide for free descent of the raised metal portion b~ gra-~ity.
~ his technical solution enables to step up the effecti-veness of stirring molten metals in high-capacit~ for accelera-ting metal portions bein~ expelled into the metal body to higher speed~ with the compressed-gas pulse acting upon . , , $;~
the ~ithdr~rQ r~ tal po~"tion ~rhicn has alread-J be~u-r. its ~-^env under the gravity forces. I~ this case t.qe enti e ener~J o~
the compressed-gas pulse is spen-t on accelera~ing the me~l portion already ;~aving some initial speed, T~hich eventuail~
resul~s in the higher speed of the exit of the ~etal jet from thc ~ump tube, and, hence, in a longer path of t~.is jet ithin the molten metal bod~, which is essential for high-capacitJ
plants. ~he action of the compressed~gas pump upon the retreatin~ -metal hampers the conditions o~ saturating the metal witn the gas , as compared with their motion against each other~
It is expedient that prior to suppl~ing said compressed--~as pulse to expel the withdrawn metal portion from the tube, the space in the tube of the pump above the metal portion -should be communicated to the ambient atmosphere.
~ he above feature provides for a more economical use of the compressed-gas energ~, owing to the arresting and preacceleration of the withdrawn metal portion being effect-ed by the energy of the a~bient atmosphere, with the metal being preaccelerated in this case b~ gravity alone. The energy of the compressed-gas pulse is then entirel~ spent on the acceleration o~ the alread~ moving metal portion in the tube, which enables to step up the speed of the exit of the metal jet from the tube, to prolong the path of the jet within the molten metal bod~ and to intensif~ the stirring process.
It is further expedient that the said compressed-gas pulse be timed with the commencing of the free gravity descent of the -~etal portion.
~ his feature enables to utilize the energ~ of the comp-- 9 ~
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, .r-~ssed ~as -o thC .lig~he t ~egree, c~;rin~ to the cc~-~rresce~ g-_ r-trea~. ~assing h~ minimuT~ necessa~ pa-t~ bO e;ecV~ er v`^l-liquid me~al in he t~be, which nas alreaay beg~ its dr-sce tS
so that i-~ e~ti~e energ~ is spent on accele~ating the .~.~era It is still further e~pcdient to perform vhe herein clisclosed method of gas-dynamic stirring of molten liq~id metals in an appa~atus co~prising a -tube with a re~lovable cover, a system ~`or s~pplying a pulse of compressed gas from a pressure accumulator via a dist.ributor into the outlet nozzle, a suction system for withdrawing metal portions, including a suction cut~off device, and a sensor of the metsl level in the molten metal bath,in which apparatus, in accordance with the present invention, the outlet no~zle is di.rected upwardly to-~rard the cover of the tube of the pu~p and is received within a movable annular sleeve ~rith a shoulder, the cover having ~oun-ted therein rod-type valves cooperating with said shoulder of the movable sleeve to communicate the internal space of the tube with the ambient atmosphere, upon the valves being raised by the movable sleeve, the latter being ope.rativel~ connected with a float submerged in the body of the raising metal portion.
The apparatus of this kind enables to mount the pump on -~
a hi~h-capacity melting furnace without the necessity of re-constructing the latter, and to provide the prerequisi~es for efficient stirring, owing to the device for communicating the internal space of the pump ~rith the ambient atmosphere being accom~odated within said space and emplo~ing for open-in~ ~ne communication the ener~y of the metai portion ascend-ing in the tube. ~he operative connection of this device with ~ 10 -.
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-~-he rr.e ~al via ~re float ensures tnat the i~l'cer~lal ,pa!e of t~-pump is co~mur~icated ~sith the am~Dien-t atr"lospnere ~aca succe~
ve c~cle of withdra~ing a metal portion into t~e tube, a.~d, consequently, provides the necessar~ prerequisites for a~vain-in~ a high speed of the exit of the metal jet fro-~ ~he tube, hen the oncoming compressed-gas pulse acts thereupon.
It is ex~edient, that said cover of the pump be provided OIl the in~ernal side thereo~ with a tapering dissector of ~he gas stream~ arran~ed axially o~ the outlet nozzle and merging wi-th an annular toroidal cavity having said rod-type valves arran-ged in the indentation thereof~
~ his feature enables to create conditions for reducing the gas saturation of the metal being expelled b~ the action of the compressed-gas pulse thereupon, owing to the compressed--~as stream being dissecte~ and uniformly distributed over the entire cross section of the tube of the pump.
It is further expedient that the float be connected with the ~ovable annular sleeve with aid of links of adjust-able len~th, interconnected through detachment assemblies.
~ his feature enables to conduct the operation of the pump at dif'ferent rates of the ascent of withdrawn metal por-tions in the tube, b~ ad7ustin~ the spacing between the float and the sleeve and by selectlng their optimum relative posi-tions in accordance with the ascent rate. Moreover, ~rovision is made for replacin~ the float and the sleeve, whenever ne-cessary.
It is further e~pedient that the cover of the tub~
of the pump should have mounted therein an electric contact ,~ - '11 -., . ~ .
~e~ice -n the LOL'~ Oi ~ probe wired i~to ~Lhe ciro~i J cc.r.'c'~o7-, the suppl~fi~g of compressed-gas pulse~, the ~ g-t`rl G~
~his probe wi~hin tne internal space of ~he tu~De beilng sel~c-tea so thev tre ti,me o~ the passage of -the wit'ndra1,.Tn mev~l pG ~ -tion along the probe up to the moment of the raisi~g of the rod-type valves should be in excess of the time of the respor.se of said system for supplying a compressed-gas pulse.
~ his feature enables to speed up the rate of the ascent of the metal in the tube of the pump, owing to the possibility of operating a~ suction values whereat the metal could have been theoretically raised above the cover of the pump~ In trlis case it is feasible, and that without any additional monitoring and control means, to time the commencing of a compressed-~as pulse with the commencing of the gravity descent of the metal portion.
It is still further expedient that the said probe of the electric contact device be mounted in the cover ~f the tube of the pump in a collet chuck providing for the advustment of the axial protrusion o~ this probe, ~ his feature enables to adjust the extent of the ascent of the metal along the probe, and, hence to time accurately the co~mencing of a compressed-gas pulse with the commencing of the gravity descent of the metal portion.
Xt is further expedient that said outlet nozzle should have at the inlet thereof the said suction cut-off device, connected in parallel with the system L or withdrawing metal portions by suction and with the syste~ for supplying compres-sed-gas pulses, the suction cut~off device including a movable - . ' .' ' ~
, r~
nozzle r~ounted a~ a v~lve mcmber in anGthcr outer cor.icsl nozzle a~d ~Gvable relative ~o the latter b~ a s~ing of ~rhich the efior~ is adjusted to close off the flow ~assage arld to set orle nozzle into the other one, as a co~pressed--~as pulse is supplied.
~ his feature enables to eliminate the influence of the suction syste~ on the conditions created for timing the co~en-cing of the co~pressed-gas pulse with the commencing of the gravit~ descent of the metal portion, owing to the vacuum or suction system becoming disconnected from the internal space of the tube of the pump at the supplying of the compressed-gas pulse and not inter~ering with the commencing of this gravity descent of the metal in the tube~ ~he feature also facilitates the corresponding adjustment of the precise ti~ing of the two operations.
~ urther~re, the last described feature enables to speed up the action of the apparatus, and, hence, the productivit~
of the pump, owing to neither specific equipment nor corres-ponding time being reguired for connecting the suction s~stem to the internal space of the tube of the pump upon the termi-nation of the action of a co~pressed~gas pulse. The frequency of the cycles~ on the other hand, is in this case readily adjustable by incorporating and adjustment throttle governing the rate of the building up o~ suction in the tube, and, conse-quently, the rate of the withdrawa~ of a metal portion from the metal molten body.
The present invention will be further described in con-- 13 ~
, ' ' 'lCC '-ion w -th i-t~ preferreà embcdiment ir. t~le follG~ .g da-,ai~a~
desc~ tion thereo~ ith reference bein~ made ~o tha accGmpa.
ii.g dra~Tings, w~arein:
lIG. 1 illus-trates schematically the state of a ~rit'~dra~,.r metal portion in the tube of the pump;
~ 'IG~ 2 is a chart OI variation of the speed of ~he ~otio-,~
of the metal portion bein~ returned into the molten metal bod~, versus time;
~ IG~ 3 is a longitudinal sectional view of the stirring apparatus, with tha control system shown schematically;
~ IG. 4 is a sectional view of the end portion of the tuhe associated with the valve in the apparatus illustrated in ~IG. 3, at the time of the suppl~ of a compressed-gas pulse;
~ IG, 5 is a sectional view of the end portion of the tube associated wi-th the valve in the apparatus illustrated in FIG. 3, when the interior of the tube com~unicates with the ambient atmosphere;
~ IG. 6 is a diagram of the control s~stem of the suppl~
of compressed~gas pulses i~ the apparatus illustrated in G. 3;
~ IG. 7 illustrates the mounting of the electric contact device - the probe ~ on the cover in the apparatus illustrated in ~IG. ~, ~ -LG. 8 illustrates the suction cut-off device of the app~ratus shown in ~IG. 3.
~ he conductin~ of the gas-d~namic stirring procass in accordance with the disclosed method i.s schematicall~ illustra-ted in the appended drawings, ~igs. 1 and 2, wherein there :
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~ , . ' v is shown the c~Jcie diagra~n of 'che opera tion O t,~4e pvmp, 7-lated to the p-rogress of the metal in the tube oP the ~u~p, CO7-responding to each successive step of the opera~ing cycle o~
the pump~ where V iS the rate of thè progress of metal in the tube,lJi~.
the "~" and tt_ll signs desig~ating, respectively, ascent and dcscent;
~ is ti~e;
P1 and P2 are the pressure values, correspondir.g,respec-tively, to the main pulse /1/ and auxiliar~ pulse /2/. - -'l'he ~ash line irl tle al~win~ illustrates for comparison the acceleration of metal in the tube in accordance with the met~od of the prior art~
~ rom the ~etal body in the bath 1, e~g~ of a melting furnace, there is ~Jithdrawn into the tu~e of a gas-d~namic pump ~ a metal portion 3 (of a preset volume) at a certain ra~e ~V, b~ suction in the working space 4 of the tube.
~ hen the metal portion in the tube is acted upon b~ an auxiliary pulse of a compressed gas at a pressure P2, e.g. air under atmospheric pressure, with the suction supply being simultaneously cut off from the working interior of the tube of the pump. Owing to this, the rate of ascent of the metal drops -to zero, so that the metal halts in the tube at a certain preset level, ~Jhereafter it starts descending in the tube~ i.e.
acguires an initial rate of the motion in the opposite direc-tion. At this moment a co~trol signal~ i.e~ one sent b~ a cor.tact-type level sensor~ initiates the supplying of the main compressed gas pulse, which accelerates the met~l in the - ' ,. : ~ .
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tube to a ~i~re~ s~d. 'nhG rletal jet issu~ at ~ni~ e~ i-i~c the ~,~olten metal body, enga~in~ the adjacent me~al la~elc a~~
thus agita-ting the metal throughout -the l~olume of ~he -~olten bod~J O
~ onducting the herein disclosed method with the timed feed o~ the two pulses is possible with either manual control from a control panel, or fro~ a control co~puter, with aid of a specific device for cutting off the suction supply and commencing simultaneously the suppl~ of the auxiliary pul~e at a pressure precluding the saturation of the metal in the tube with ~as. It is expedient to conduct the herein disclosed method with the auxiliary pulse being followed b~ the ~ain pulse with a delay egualling the time of passage of the control action through the system.
Given hereinbelow is an exa~ple of employing the herein disclosed method at the melting of alu~inum alloy, with the molten metal body being stirred at every melting stage in a meltin~ furnace of the 30-ton capacity.
~ he gas-d~namic pump was operated with the freguency or rate of the supply of compressed-gas pulses within a range from 4 to 20 pulses per minute. While the metal portion in the tube was accelerated and expelled into the molten metal body, it was successivel~ ac-ted upon by two pulses. ~he first pulse - t-~ie auxiliary o~e - was with aix under the pressure of 1 atmosphere abs., i.e~ under the atmospheric pressure, by simultaneously cutting o~f the suctio~ suppl~ to the worXing space and communicatin~ the latter with the ambient atmosphere.
~his resulted in the rate of ascent of the ~etal in the tube , ' - , , . , , ,:
' d-ro-~pin~ i o~ 1~ m/s (et O,L~ a-tm suctiorl) -tG ~f,rO aLd cha~g Ig to a descent in 0.~ .~. 0.8 second, following -t~e inltia'io. 5-tl~e auxiliary p~essure pulse supply. So, in 0.5 seco~d afte~
t~le initiation of the auxiliar-~ pulse supply the control signal was sent, and in about 0~1 second after that t`ne actuav-in~ T2ember - the distributor - responded, and the main pressure pulse at a 5.0 atm~ pressure accelerated the metal from the initial ra-te o~ 0~5 m/s (following the termination of the action of the auxiliary pulse) to about ~.5 m/s b~ the time of the termination of the action of the main cor~pressed-gas pulse.
~ hus, in the abovedescribed manner there was effectuated the acceleration of metal portions for gas~d~namic stirring at ever~ melting stage, irrespectivel~ of the ratf of the supplying of the pressure pulses, which enabled to cut down the melting time b~ 10%, as compared with the method of the prior art.
~ he abo~edescribed stirring mode was maintained until the mol~e~l ~etal was poured out into the mixer.
r~he above example of conducting the method, quite under-standabl~, doe~ not by far restrict the parameters of the process or preclude other ways of conducting the method as de-fined in the Claims to follow.
~ he herei~ disclosed method, a~ experience shows, enables to step up the ef~ici0nc~ of the stirring and to cut down the melting ti~e b~ as much as 15%.
Indicated with arrows in Fig~ 3, 4 and 5 of the append-ed dra~Jings are the xespective directions of the progress of the metal and of the gas streams. In a preferred embodiment, - .
-the ~u~ --or ga~ JnamiC sti.ring oi liquid ~e~<-ll 5 in vhr-bath Or a furrace 6 includes an interrAall~ lin~d ~u~e 7 wi~h a removable cov~r 8 and a nozzle 9 having i~s outl~t direo~ed toward the cover ~ he nozzle 9 is connected via a line 10 with a d~vic~ 'i1 for cutting oif the vacuum or suction suppl~ fro~ the tube. ~he device 11 is also opera~ivel~
colmected ~ith a distributor controlling the suppl~ing of pulses of compressed gas (nitrogen, argon, etc.) from a pres-sure accumulator 13. ~he pressure accumulator 1~ is of a given appropriate volume, with provisions for adjusting -this volume in accordance with the pressure of the gas, maintained with a pressure regulator 14. ~he intexnal working space of the tube 7 is in permanent communication via the nozzle ~, the line 10 and an injector 11 with a suction line 15 including a controllable throttle 16 which enables to ~overn the rate of ascent of metal in the tube. ~here is a contact sensor (not shown) of the me~al level in the tube, wired to send a control signal to the sole-noid of the distributing valve 12.
The cover 8 is provided with a tapering dissecting element 17 adapted to dissect the stream of the gas, the dissecting els-ment 17 being arranged axially of the nozzle 9 and ~erging with a torodial annular cavit~ 18 intended to st~bilize the gas strea~ in the tube o~ the pumpv ~he nozzle 9 is encompassed b~ an annular sleeve 19 with a shoulder, movable along this nozzle 9~ ~he sleeve 19 abuts against a ring 20 adJustable longitudinall~ of the nozzle, i~ which wa~ the required clear-ance between the sleeve 19 and the cover 8 can be set~ ~he sleeve 1~ is operativel~ connected by adjustaDle-length 1L~ S
21 to a floa~ 22. This connection enables to adjust the spa-cing between the sleeve 19 and the float 22, and thus to time the ~ornent when the sleeve 19 closes away the suctiGn line and co~unicates the workin~ space wi-th the a~bient atmosphere. '~he float 22 is preferably made of a light~eight refractory material, e.g. asbestos-thermosilicate and the li~e, or else it can be a hollow member with the case made of a ~etal insoluble in the alloy being stirred. The float 22 is preferably streamlined to minimize its opposition to the ~as stream. It ma~ have an arcuate ~op, or a truncated bottom; alternativel~, it may be droplet~shaped, conical, etc. ~reel~J suspended fro~
the cover 8 are rod-type valves 23 with dishes 24 adapted to close the passages 25 commu~icating the worXin~ space of the tube 7 with the a~bient atmosphere. In a modification of the apparatus, this communication is not with the ambient air, but with a space ~illed with a gas under gauge pressure below that in the pressure accumulator, to provide a "soft"
pulse.
~he herein disclosed pump operate~$ as follows.
With the metal 5 filling the bath of the furnace 6 to a certai~ level whereat the outlet of the tube 7 is not expo-sed~ the suction li~e 15 is co~nected to the i~texnal working space o~ the tube 7, and the pressure accumulator 13 is connec-ted to a compressed~gas source via the distrib~ti~g device 12 and the pressure re~ulator 14. Simultaneousl~ voltage is sup-plied to the coil of the solenoid of the distributing device 12; the rod o~ the contact ~enæor bein~ lowered to a preselect-ed level, depen~ing on the setting of the throt~le 16 arl~ 'vhexelative posivions of the float 22 and t~e sleeve ~I9.
~ he suction raises the li~uid metal into the tube 7 to a certain height, the float 22 with the sleeve 19 bein~ raised accordingly. Eventially the sleev2 19 raises the rod-type valves
2~ b~ its shoulder, the dishes or valve members 24 opening the passages 25 communicating the interior of the tube with the ambient atmosphere, while the sleeve 19 starts closing the connection between the working space of the tube and the suction souxce. ~he metal ascends at a slowing rate and at a certain moment stops on account of the lifting force resulting fro~ the pressure drop and the weigh-t of the metal counter-balancing each other. ~t this ~oment the contactwtype level sensor responds, and the solenoid of the distributor 12 operates, whereb~ the pressure accumulator 1~ becomes connected with the working interior of the tube 7 via the injector 11, the line 'lO and the no~zle 9, the injector cutting of`f the suction suppl~, and the compressed gas from -the pressure accumulator 13 swiftly flowing into the working space. ~he pressure pulse acts upon the metal body in the tube and expels it at a high velocit~
into the molten metal bod~ in the bath. The duration of the pulse can be extended b~ any suita'ole known per se means used for the purpose. ~he metal portion expelled in a high-velocity jet from the tube advances through the bath and enga~es the adjacent layexs of the molten metal body, in which way the whole volu~e of the molten metal bod~ in the bath is agitated.
; ~pon the ~etal in the tube clearing the rod of the con-tact sensor, the solenoid of the distributlng dsvice 12 is ' , . -- ~0 --, , ' -: , ' : ,, , , , ' , , :' .
,~ , 6~
dc~ne~ized, and the cor~pressed ~as is suppiie~ rito t~e ~
sure accumulator 13 from the co~pressed gas source. Tr,en a~o~.-e--portion of liquid me~al is withdrawn by suctio~ into the tube, and ~h~ abovedescribed operating c~cle of the apparatus i5 re-peated.
The apparatus in accordance with the present invention is operable equally efficiently ~ith the tube of the pu~p bein~ either stationar~ or movable.
~ he herein disclosed pump enables to stap up the effici-ency of the meltin~ process and to cut down the melting time~
e.~O of aluminum alloys by as much as 15%.
~ he cover 26 of the apparatus has mounted thereon, in the presently described embodiment, the main contact-type level sensor o~ which the probe 27 is connected to one of the contacts of the solenoid of the distributin~ device 28, while 12 V voltage is supplied to the other contact~ ~he metal bod~ in the bath is earthed, therefore, upon the metal contacting the probe 27, the solenoid of the distributing device operates, with the line "12V voltage source - eaxth" being completed. ~he probes 27 of thc contact-t~pe sensors are mounted in nut-tightened collet chucks 29, which enables to easil~ adjust the spacing of the probes froTn the cover 26, and thus to adjust the operative volume of the wor~ing space of the ~ube ~00 ~ throttling, it is ~possible to adjust the time of attaining the reguired subatmospheric pressure in the working space of the tube, and t'nus to adjust the rate of the ascent of the me~al to the preset height.
~he hérein described em~odiment o~ the apparatus operates, ^ 21 -;
as follows.
~ ith thc molten metal in the bath of the fur;^ace a~telrl-ing a given per~.issible level whereat the outlet of the ~u~e ~0 is no~ ~xposed, the vacuum or suction line 31 is connected to the workin~ space of the tube 30, and the pressure accumula-tor ~2 is connected -to a compressed gas source via the dis~ri- -buting device 28 and the pressure regulator 33. Simultaneously, voltage is supplied to -the coils of the solenoids of the discri-buting device 28, the probes ~7 of the level sensors having been lowered to a preselected level in accordance with the setting of the throttling member governlng the rate of ascent of the metal in the tube 30 at the ~iven subatmospheric pressure -suction - in the suction s~stem.
~ he liquid metal is lifted b~ suction in th~ tube 30 to the preset height whereat it contacts the probe 27 of the contact sensor, whereb~ the electric line "earth - 12V source"
is completed, and the solenoid of the distributing device 28 operates~ ~he pressure accumulator 32 is connected to the working space of the tube 30 via the line 3'l and the nozzle 34, and ~he compressed gas stored in the pressure accu~ulator swiftl~ flows into the ~orking space. The compressed-gas pulse acts upon the bod~ of metal in the tube and expels it in a high-velocit~ ~et into -the metal bod~ in the bath~ The por-tion of the liquid metal expelled from the tube moves through the metal bod~ in the bath, engaglng the adJacent layers of metal and thus agitat~.ng the entire metal body in the bath.
Upon the metal in the tube clearing the probe 27, the completed electric lins "earth - voltage source`' becomes bro-, ., ., - ' ,: ' : ~', -,. , . :
. , - , ~
", ~, ' .
ken, the solenoid o~ the distributing de~ice 2~ is deerie,g-zed;
and compress~d gas starts flowin~ into the p~essure accu~-.u}~-tor 32 from the pressure line 35. ~.hen liquid metal is orce again withdrawn b~ suction in-to tAe tube, and the abovedesc~.i-bed cycle of the operation of the apparatus is repeated, The abovespecified structure of -the apparatus for stirring liquid metal of~ers a greater efficienc~ and capacity, o~ring to the filler utilization of the working volume of the tube, with relatively high suction values in the system.
Described hereinbelow in more detail is the prefe~red embodiment of the suction cut~off device of the gas-dynamic pump.
~ he suction cut-off device of the gas-d~namic pump for stirring molten metal includes the chamber of the stationary nozzle 36. Received within the nozzle 36 is a movable nozzle 37 connected via the line~ 31 (~IG. 6) with the distributing device 28 of the s~stem supplying pulses of compressed gas (nitrogen, argon, etc r ) ~ ~rom the pressure accumulator 32 filled from the pressure supply lin~ through the pressure regulator 33. Interposed.between the shoulder 38 of the nozzle and the annular groove 39 merging with the tapering surface 40 of the chamber is a xesilient member, e.g. a compression sprin~ 44 maintaining the nozzle 37 in a suspen-ded or floating state. ~he clearance between the end face of the no~zle 37 and the tapering surface 40 is adJus-table with aid of a lid 41 threadedly connected with the nozzle 36. ~he outle-t portion of the nozzle 37 has made therein passages 42 communi-~,, . ,, - .
, . .
- . ,, '' -.
ca~ing the co~pressed-gas pulse suppl~ line ~ri~h the space L~
iIlter~ediate tne external and internal surfaces ol the nozzl~
37 and of thc cha~ber of the nozzle ~6, respectively. ~he de-vice operates, as follows~
In -the initial position, shown in ~i~. 8, the suc-tion line ~ communicates with the chamber of the nozzle 36, ~.rhile compressed gas is supplied vla -the distributing device 23 (~`IG. 6) into the pressure accumulator 32, With the distribut-ing device 28 switchin~ over, the co~pressed gas stored in the accumulator 32 flows via the line 31 to the nozzle 37 (~IG. 8). With thc gas ~lowin~ through the nozzle ~ nere is created a pressure drop across the nozzle, i.e, before and after the nozzle~ At the same time, compressed gas flows via the passages 42 into the chambsr ~3 and acts upon the area defined by the surface of the shoulder of the nozzle. The nozzle 37 is driven by the pressure of compresse~ gas upon the shoulder 38 until the end ~ace of the nozzle 37 abuts against the tapering surface 40 of the passage~ cutting off the suctionsupply line from the internal space of the tube.
The spring 44 is compressed by this same effort and remains compressed until the compressed-gas pulse is terminated. With the pulse terminated, the sprin~ 44 returns the nozzle 37 upwardl~ into the initial position.
Then ~he abovedescribed operating c~cle is repeated in the sa~e sequence.
~ he last described general structure can be associated both with a stationar~ pump tube and a mobile one, its incor-poration enabling to step up the productivity of the pump used with suction plants b~ 8 .,. '10% on the average.
~24-- - . - : - , ' :
,. ..
into the molten metal bod~ in the bath. The duration of the pulse can be extended b~ any suita'ole known per se means used for the purpose. ~he metal portion expelled in a high-velocity jet from the tube advances through the bath and enga~es the adjacent layexs of the molten metal body, in which way the whole volu~e of the molten metal bod~ in the bath is agitated.
; ~pon the ~etal in the tube clearing the rod of the con-tact sensor, the solenoid of the distributlng dsvice 12 is ' , . -- ~0 --, , ' -: , ' : ,, , , , ' , , :' .
,~ , 6~
dc~ne~ized, and the cor~pressed ~as is suppiie~ rito t~e ~
sure accumulator 13 from the co~pressed gas source. Tr,en a~o~.-e--portion of liquid me~al is withdrawn by suctio~ into the tube, and ~h~ abovedescribed operating c~cle of the apparatus i5 re-peated.
The apparatus in accordance with the present invention is operable equally efficiently ~ith the tube of the pu~p bein~ either stationar~ or movable.
~ he herein disclosed pump enables to stap up the effici-ency of the meltin~ process and to cut down the melting time~
e.~O of aluminum alloys by as much as 15%.
~ he cover 26 of the apparatus has mounted thereon, in the presently described embodiment, the main contact-type level sensor o~ which the probe 27 is connected to one of the contacts of the solenoid of the distributin~ device 28, while 12 V voltage is supplied to the other contact~ ~he metal bod~ in the bath is earthed, therefore, upon the metal contacting the probe 27, the solenoid of the distributing device operates, with the line "12V voltage source - eaxth" being completed. ~he probes 27 of thc contact-t~pe sensors are mounted in nut-tightened collet chucks 29, which enables to easil~ adjust the spacing of the probes froTn the cover 26, and thus to adjust the operative volume of the wor~ing space of the ~ube ~00 ~ throttling, it is ~possible to adjust the time of attaining the reguired subatmospheric pressure in the working space of the tube, and t'nus to adjust the rate of the ascent of the me~al to the preset height.
~he hérein described em~odiment o~ the apparatus operates, ^ 21 -;
as follows.
~ ith thc molten metal in the bath of the fur;^ace a~telrl-ing a given per~.issible level whereat the outlet of the ~u~e ~0 is no~ ~xposed, the vacuum or suction line 31 is connected to the workin~ space of the tube 30, and the pressure accumula-tor ~2 is connected -to a compressed gas source via the dis~ri- -buting device 28 and the pressure regulator 33. Simultaneously, voltage is supplied to -the coils of the solenoids of the discri-buting device 28, the probes ~7 of the level sensors having been lowered to a preselected level in accordance with the setting of the throttling member governlng the rate of ascent of the metal in the tube 30 at the ~iven subatmospheric pressure -suction - in the suction s~stem.
~ he liquid metal is lifted b~ suction in th~ tube 30 to the preset height whereat it contacts the probe 27 of the contact sensor, whereb~ the electric line "earth - 12V source"
is completed, and the solenoid of the distributing device 28 operates~ ~he pressure accumulator 32 is connected to the working space of the tube 30 via the line 3'l and the nozzle 34, and ~he compressed gas stored in the pressure accu~ulator swiftl~ flows into the ~orking space. The compressed-gas pulse acts upon the bod~ of metal in the tube and expels it in a high-velocit~ ~et into -the metal bod~ in the bath~ The por-tion of the liquid metal expelled from the tube moves through the metal bod~ in the bath, engaglng the adJacent layers of metal and thus agitat~.ng the entire metal body in the bath.
Upon the metal in the tube clearing the probe 27, the completed electric lins "earth - voltage source`' becomes bro-, ., ., - ' ,: ' : ~', -,. , . :
. , - , ~
", ~, ' .
ken, the solenoid o~ the distributing de~ice 2~ is deerie,g-zed;
and compress~d gas starts flowin~ into the p~essure accu~-.u}~-tor 32 from the pressure line 35. ~.hen liquid metal is orce again withdrawn b~ suction in-to tAe tube, and the abovedesc~.i-bed cycle of the operation of the apparatus is repeated, The abovespecified structure of -the apparatus for stirring liquid metal of~ers a greater efficienc~ and capacity, o~ring to the filler utilization of the working volume of the tube, with relatively high suction values in the system.
Described hereinbelow in more detail is the prefe~red embodiment of the suction cut~off device of the gas-dynamic pump.
~ he suction cut-off device of the gas-d~namic pump for stirring molten metal includes the chamber of the stationary nozzle 36. Received within the nozzle 36 is a movable nozzle 37 connected via the line~ 31 (~IG. 6) with the distributing device 28 of the s~stem supplying pulses of compressed gas (nitrogen, argon, etc r ) ~ ~rom the pressure accumulator 32 filled from the pressure supply lin~ through the pressure regulator 33. Interposed.between the shoulder 38 of the nozzle and the annular groove 39 merging with the tapering surface 40 of the chamber is a xesilient member, e.g. a compression sprin~ 44 maintaining the nozzle 37 in a suspen-ded or floating state. ~he clearance between the end face of the no~zle 37 and the tapering surface 40 is adJus-table with aid of a lid 41 threadedly connected with the nozzle 36. ~he outle-t portion of the nozzle 37 has made therein passages 42 communi-~,, . ,, - .
, . .
- . ,, '' -.
ca~ing the co~pressed-gas pulse suppl~ line ~ri~h the space L~
iIlter~ediate tne external and internal surfaces ol the nozzl~
37 and of thc cha~ber of the nozzle ~6, respectively. ~he de-vice operates, as follows~
In -the initial position, shown in ~i~. 8, the suc-tion line ~ communicates with the chamber of the nozzle 36, ~.rhile compressed gas is supplied vla -the distributing device 23 (~`IG. 6) into the pressure accumulator 32, With the distribut-ing device 28 switchin~ over, the co~pressed gas stored in the accumulator 32 flows via the line 31 to the nozzle 37 (~IG. 8). With thc gas ~lowin~ through the nozzle ~ nere is created a pressure drop across the nozzle, i.e, before and after the nozzle~ At the same time, compressed gas flows via the passages 42 into the chambsr ~3 and acts upon the area defined by the surface of the shoulder of the nozzle. The nozzle 37 is driven by the pressure of compresse~ gas upon the shoulder 38 until the end ~ace of the nozzle 37 abuts against the tapering surface 40 of the passage~ cutting off the suctionsupply line from the internal space of the tube.
The spring 44 is compressed by this same effort and remains compressed until the compressed-gas pulse is terminated. With the pulse terminated, the sprin~ 44 returns the nozzle 37 upwardl~ into the initial position.
Then ~he abovedescribed operating c~cle is repeated in the sa~e sequence.
~ he last described general structure can be associated both with a stationar~ pump tube and a mobile one, its incor-poration enabling to step up the productivity of the pump used with suction plants b~ 8 .,. '10% on the average.
~24-- - . - : - , ' :
,. ..
Claims (9)
1. In a method of gas-dynamic stirring of molten liquid metals, including alternatingly withdrawing metal portions from the molten metal body into the tube of a pump by suction and expelling these metal portions back into the molten metal body by the action thereupon of compressed-gas pulses, an improvement including, directly prior to the supplying of the said compressed-gas pulse into the tube of the pump, cutting off the action of the suction, to provide for free descent of the lifted metal portion by gravity forces.
2. A method of gas-dynamic stirring of molten liquid metals, as set forth in claim 1 wherein, prior to the supply-ing of said compressed-gas pulse to expel from the tube the withdrawn metal portion, the internal space of the tube of the pump is communicated with the ambient atmosphere.
3. A method of gas-dynamic stirring of molten liquid metals, as set forth in claim 1, wherein said compressed-gas pulse is timed to the commencing of the free gravity descent of the metal portion.
4. An apparatus for gas-dynamic stirring of molten liquid metals including a pump and molten metal bath, com-prising: a tube with a removable cover; a system for supply-ing compressed-gas pulses, including an outlet nozzle, a pressurized-gas accumulator and a gas-distributing device, a suction system for withdrawing a metal portion into the tube of the pump, including a suction cut-off device; a sensor of the metal level in the molten metal bath, said outlet nozzle being directed upwardly toward said cover of the tube of the pump and encompassed in a movable annular sleeve with a shoulder, the cover having mounted therein rod-type valves adapted to cooperate with said shoulder of the movable sleeve, to communi-cate the internal space of the tube with the ambient atmosphere upon the valves being raised by the action of the movable sleeve operatively connected with a float submerged in the molten metal.
5. An apparatus for gas-dynamic stirring of molten liquid metals, as set forth in claim 4, wherein said cover is provided on the internal side thereof with a tapering dissector for the streaming of the gas, extending axially of the outlet nozzle and merging with an annular toroidal cavity of which an iden-tation accommodates said rod-type valves.
6. An apparatus for gas-dynamic stirring of molten liquid metals, as set forth in claim 4, wherein said float is operative-ly connected with said movable annular sleeve via links of adjustable length, interconnected through detachment assemblies.
7. An apparatus for gas-dynamic stirring of molten liquid metals, as set forth in claim 4, wherein said cover of said tube of the pump has mounted therein an electric contact device including a probe wired into a circuit controlling the supply of the compressed-gas pulses, the working length of the probe within the internal space of the tube being selec-ted for the time of the passage of the withdrawn metal portion along the probe before the lift-off of the rod-type valves to be in excess of the time of the response of said system supplying the compressed-gas pulse.
8. An apparatus for gas-dynamic stirring of molten liquid metals, as claimed in claim 7, wherein said probe of the electric contact device is mounted in said cover of the tube of the pump in a collet chuck, to provide for the ad-justability of the axial outreach of the probe.
9. An apparatus for gas-dynamic stirring of molten liquid metals, as set forth in claim 4, wherein said outlet nozzle is provided at the inlet thereof with said suction cut-off device connected in parallel with said suction system for withdrawing a metal portion and with said system for supply-ing compressed-gas pulses, the cut-off device including a movable nozzle mounted as a valve member internally of another external conical nozzle and urged from the latter by a spring of which the effort is adjusted for the communication passage therebetween provided to be closed off and for one nozzle to engage the other one as a compressed-gas pulse is supplied.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SU772512971A SU759605A1 (en) | 1977-07-25 | 1977-07-25 | Method of gas dynamical stirring of liquid metals |
| SU2512971 | 1977-07-25 | ||
| SU2521140 | 1977-08-30 | ||
| SU2521140 | 1977-08-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1106600A true CA1106600A (en) | 1981-08-11 |
Family
ID=26665634
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA307,895A Expired CA1106600A (en) | 1977-07-25 | 1978-07-21 | Gas-dynamic stirring of liquid molten metals |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5926876B2 (en) |
| AT (1) | AT364538B (en) |
| CA (1) | CA1106600A (en) |
| CH (1) | CH633728A5 (en) |
| FR (1) | FR2398806A1 (en) |
| GB (1) | GB2002644B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5643374B2 (en) * | 1978-08-07 | 1981-10-12 | ||
| DE3036615A1 (en) * | 1980-09-29 | 1982-05-13 | Siemens AG, 1000 Berlin und 8000 München | METHOD FOR PRODUCING RESIST STRUCTURES |
| JPS58185730A (en) * | 1982-04-23 | 1983-10-29 | Shinmei Eng Kk | Control device for stirrer for molten metal |
| KR940003506B1 (en) * | 1989-12-15 | 1994-04-23 | 스미도모 게이긴조꾸고오교오 가부시기가이샤 | Molten metal stirring device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3490896A (en) * | 1966-09-07 | 1970-01-20 | Kaiser Aluminium Chem Corp | Process for improving mixing efficiency |
| US4008884A (en) * | 1976-06-17 | 1977-02-22 | Alcan Research And Development Limited | Stirring molten metal |
-
1978
- 1978-07-21 CA CA307,895A patent/CA1106600A/en not_active Expired
- 1978-07-24 CH CH794678A patent/CH633728A5/en not_active IP Right Cessation
- 1978-07-24 FR FR7821863A patent/FR2398806A1/en active Granted
- 1978-07-25 JP JP53090871A patent/JPS5926876B2/en not_active Expired
- 1978-07-25 AT AT0540078A patent/AT364538B/en not_active IP Right Cessation
- 1978-07-25 GB GB7830981A patent/GB2002644B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| ATA540078A (en) | 1981-03-15 |
| JPS5926876B2 (en) | 1984-07-02 |
| FR2398806A1 (en) | 1979-02-23 |
| CH633728A5 (en) | 1982-12-31 |
| GB2002644B (en) | 1982-03-03 |
| FR2398806B1 (en) | 1980-07-18 |
| GB2002644A (en) | 1979-02-28 |
| AT364538B (en) | 1981-10-27 |
| JPS5441207A (en) | 1979-04-02 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |