SE203015C1

SE203015C1 -

Info

Publication number: SE203015C1
Authority: SE
Publication date: 1965-01-01

Description

Uppfinnare: F H Sonkman Prioritet begard fran den 12 februari 1960 (Nederldnderna) Foreliggande uppfinning avser ett forfaringssatt och en anordning fOr vatsiktning av fasta partiklar. Inventor: F H Sonkman Priority Required from February 12, 1960 (The Netherlands) The present invention relates to a method and a device for water sieving solid particles.

Det är kant att vatsiktning kan anvandas antingen for att ur ett av partiklar bestaende utgangsmaterial separera en finfraktion belt eller huvudsakligen bestaende av partiklar under en viss storlek eller for att separera vatska fran en suspension bestaende av vatska och fasta partiklar. I det forsta fallet kan utgangsmaterialet separeras sà att man samtidigt erhaller en grovfraktion, som belt eller till storre delen bestar av partiklar over en viss storlek. It is preferred that water screening can be used either to separate a fine fraction belt from a starting material consisting of particles or to consist mainly of particles under a certain size or to separate liquid from a suspension consisting of liquid and solid particles. In the first case, the starting material can be separated so that a coarse fraction is obtained at the same time, which belt or for the most part consists of particles over a certain size.

Det Sr na5jligt att utfora en vatsiktning genom att lata partiklarna och vatska stromma langs. ena sidan av ett siktbord, sasom exam-pelvis är kant genom de vatsiktningsmetoder som beskrivas i den svenska patentskriften ,8 671. I denna patentskrift beskrives en vatsiktningsmetod for fasta partiklar, vilken princip bestar dari att partiklarna uppblandas i en vatska vilken bringas att stromma som ett skikt langs den konkava sidan av ett siktbord, vilket bestar av sig vinkelratt mot stro.mningsriktningen strackande stanger anordnade pa nagot avstand fran varandra i stromningsriktningen och som är kr8kt 'dugs stramningslinjen, varvid stromningshastigheten samt dimensionerna pa stangerna oeh avstanden dem emellan aro sadana att ett vatskesubstat eller ett vatskesubstrat mer partiklar strommar genom spalterna mellan stangerna pa grund av sin kinetiska energi och inte eller endast i obetydlig utstrackning pa grund av tyngdkraften. Detta forfaringssalt- liar mhnga fordelar gentemot tidigare tillampade vatsiktningsmetoder, i synnerbet genom att det medger ekonomisk separering av partiklar med en storlek vasentligt mindre an 1 mm och till och med mindre an 0,5 mm utan att siktbordet satts igen, eftersom det an att valja stromningsforhallandena sadans_ att partikelstorleken i den underfraktion (dvs. den fraktion som paserar genom siktbordet), som erhalles vid separering av en blandning av partiklar i fraktioner av olika storlek, icke Sr vasentligt storre an halva bredden av spalterna i siktbordet. It is convenient to perform a water screening by letting the particles and liquid flow along. one side of a sight table, which is, for example, edged by the water sieving methods described in the Swedish patent specification, 8 671. This patent specification describes a water sieving method for solid particles, which principle consists in mixing the particles in a liquid which is caused to flow as a layer along the concave side of a sight table, which consists of perpendicularly to the direction of flow stretching rods arranged at some distance from each other in the direction of flow and which are curved in the flow line, the flow rate and the dimensions of the rods and the distance between them being such that a liquid substrate or a liquid substrate more particles flow through the gaps between the rods due to their kinetic energy and not or only to an insignificant extent due to gravity. This process salt has many advantages over previously applied water screening methods, in particular in that it allows economical separation of particles with a size substantially less than 1 mm and even less than 0.5 mm without the screen being clogged, since it is possible to choose the flow conditions such that the particle size of the subfraction (i.e., the fraction passing through the screen) obtained by separating a mixture of particles into fractions of different sizes is not substantially greater than half the width of the slits in the screen.

Vid utforandet av en vatsiktning, som fordrar att vatskan och partiklarna oavbrutet strOmma flings ett siktbord besthende av pa avsthnd frhn varandra, vinkelratt mot stromningsriktningen anordnade stanger, Sr bordet utsatt for en avsevard forslitning, i synnerhet am partiklarna aro, mycket notande. Denna farslitning upptrader framf5rallt vid de kanter ph stangerna, mot vilka vatskan och partiklarna stota, nSr det passera Over spalterna, och Sr storst i narheten av det stalle dar Tatskan tillfOres siktbordet. When performing a water screening, which requires the liquid and the particles to flow continuously, a screening table consists of rods arranged at a distance from each other, perpendicular to the direction of flow, the table is subjected to considerable wear, in particular if the particles are very worn. This danger wear occurs mainly at the edges of the rods, against which the liquid and the particles strike, when it passes over the gaps, and is greatest near the stable where the Tatskan is fed to the sight table.

De kanter ph stangerna, frAn vilka materialet strommar over spalterna, aro, iae utsatta for en forslitning i samma utstrackning. Forslitningen kan goras mer likformig genom att periodiskt vanda pa. stronmingsriktningen i forhallande till siktbordet. Sasom beskrivits i patentskriften 148 611, leder forslitningen av kanterna pa ena sidan av separeringsspalterna sa smaningam till en minskning av den partikelstorlek vid vilken separeringen ager rum, medan en omkastning av stromningsriktningen, sS att joke forslitna eller mindre forslitna kanter ph stangerna utsattas for vatske- och partikelstrommen, aterstaller separeringsstorleken till sitt ursprungliga_varde 2, , eller atminstone till ett hogre varde. F6r att underlatta omkastningen_ ay stramningsriktning beskrives I namnda patentskrift en vatsiktningsanlaggning, vid vilken siktbordet är krakt efter en oppen kurva oeh organen for tillforsel ay vatska och partiklar till siktbordet aro forflyttbart anordnade, sa att varje ande pa separeringsbordet kan alternativt vara pamatningsande och utmatningsande. Ett flertal olika alternativa apparater till de som beskrivas i namnda patentskrift ha senare foreslagits, med vilka ett material kan vatsiktas genom att det strommar langs ytan av ett siktbord forst frail den ena mil sedan fill' den andra andel" av bordet. The edges of the rods, from which the material flows over the gaps, are exposed to wear to the same extent. Wear can be made more uniform by periodically watering. the direction of the current in relation to the sight table. As described in U.S. Pat. No. 148,611, the wear of the edges on one side of the separation gaps so gradually leads to a reduction in the particle size at which the separation takes place, while a reversal of the flow direction, so that joke worn or less worn edges of the rods are exposed to water and the particle stream, restores the separation size to its original value 2,, or at least to a higher value. In order to facilitate the reversal in the direction of tightening, said patent specification describes a water screening plant, in which the screen is cracked according to an open curve and the means for supplying liquid and particles to the screen are movably arranged, so that each spirit on the separating table can alternatively be feeding and dispensing. A number of different alternative apparatus to those described in the said patent have later been proposed, with which a material can be water-sieved by flowing along the surface of a screen table only one mile then filling the "other part" of the table.

De hittills f8reslagna och beskrivna anordningarna for omkastning av stramningsriktflinger" Oro joke tillfredsstallande. Salunda 'nage siktningsforfarandet avbrytas, medan siktbordet och pamatningsanordningarna forflyttas till varandra. Dessuto.m Or det uppenhart, att vid anvandningen av ett siktbord av stanger, sasom beskrivet i den namnda patentskriften, kommer en omkastning av stromningsriktningen att medfora en sprangartad andring av den partikelstorlek vid vilken separeringen ager rum. The hitherto proposed and described devices for reversing tightening directional flakes "Oro joke satisfactory. Salunda 'nage screening procedure is interrupted while the screen and the loading devices are moved to each other. Moreover, it is obvious that when using a screen of bars, as described in patent, a reversal of the flow direction will result in a sudden change in the particle size at which the separation takes place.

Avsikten med foreliggande uppfinning är att astadkomma en vatsiktningsmetod och en anordning for sadan vatsiktning, vid vilken en likformig forslitning av siktbordet erhalles, utan att det Or nadvandigt att avbryta drifter' av anlaggningen. The object of the present invention is to provide a water screening method and a device for such water screening, in which a uniform wear of the screening table is obtained, without it being necessary to interrupt operations of the plant.

' Foreliggande uppfinning avser saledes ett forfarande far vatsiktning av ett utgangsmaterial innehallande fasta partiklar, sa. att fraktioner av .partiklar med olika storlek separeras fran varandra eller sa att vatskan separeras frail partiklarna, yaryid en vatska, i vilken partiklarna Or uppblandade, bringas att stromma langs insidan av ett cylindriskt krokt siktbord bestaende ay pa aystand frau varandra anordnade, med cylinders axel pa- rallellaoch kannetecknas darav, att vatskan med partiklarna hringas att strainma i tva skikt med konkava stromningslinjer och med motsatta, mot namnda stanger i huvudsak vinkelrata, stromningsriktningar under det att siktbordet kontinuerligt eller intermittent vrides runt sin axel i en riktning. Thus, the present invention relates to a process for water sieving of a starting material containing solid particles, said. that fractions of particles of different sizes are separated from each other or so that the liquid is separated from the particles, yaryid a liquid in which the particles Or are mixed, is caused to flow along the inside of a cylindrical curved sight table consisting of spaced apart, with cylindrical axis parallel and can be characterized in that the liquid with the particles is circled to strain in two layers with concave flow lines and with opposite, towards said rods substantially perpendicular, flow directions while the sight table is continuously or intermittently rotated around its axis in one direction.

Foretradesvis Or hastigheten, 'Tied vilken siktbordet kontinuerligt eller intermittent vrides, oeh hastigheten av de strammande skikten sadana, att stromningshastigheten for vane skikt i forhallande till siktbordets inneryta Or minst sa. stor som den hastighet, vid vilken den maximala partikelstorleken i en underfraktio.n joke Or st5rre On halva bredden av spalterna mellan stangerna. Sarskilt i det fall att siktningen skall ske enIigt den i den namnda patentskriften 158 671 beskrivna metoden, skola stromningslinjerna. far de skilda skikten i huvudsak ligga i ett plan, som Or vinkelratt mot cylinderns axel. - De tva stromningsskikten starta foretradesvis i motsatt riktning frau narbelagna tillforseloppningar. Anordningen kan vara utford med det cylindriska siktbordets axel horisontell och stromningsskikten kunna stromma uppat langs innerytan pa motsatta sidor av cylindern. Stromningshastigheten 1 forhallande till krokningsradien for siktbordet kan vara sadan, att de tva skikten stota samman yid toppen. Alternativt kunna lagre stromningshastigheter anvandas, sa att de tva skikten, vilka innehalla vatska och partiklar som icke passerat genom siktbordet, lamna detta nar de narma sig varandra och under inverkan av tyngdkraften falla i paraboliska banor in mot cylinderns centrum for att uppsamlas i en lamplig .anordning. Siktningsanlaggningen kan vara forsedd tried ett holje runt siktbordet f Or uppsamling av den vatska och de partiktar med en storlek mindre On separeringsstorleken, som passera genom siktbordet. Preferably, the speed at which the screen is continuously or intermittently rotated is the speed of the tightening layers such that the flow rate of the usual layer in relation to the inner surface of the screen is at least said. greater than the velocity at which the maximum particle size of a subfraction.n joke Or greater On half the width of the gaps between the rods. Especially in the case that the screening is to take place according to the method described in the said patent specification 158 671, the flow lines must be. the different layers may lie essentially in a plane which is perpendicular to the axis of the cylinder. - The two flow layers preferably start in the opposite direction from adjacent supply openings. The device may be challenged with the axis of the cylindrical sight table horizontal and the flow layers may flow upwards along the inner surface on opposite sides of the cylinder. The flow velocity 1 relative to the hooking radius of the sight table can be such that the two layers collide at the top. Alternatively, lower flow rates can be used, so that the two layers, which contain liquid and particles that have not passed through the sight table, leave this when they approach each other and under the influence of gravity fall in parabolic paths towards the center of the cylinder to be collected in a lamp. device. The screening plant may be provided with a casing around the screening table for collecting the liquid and the particles of a size smaller than the separation size, which pass through the screening table.

Vid utforandet av en siktning enligt Vidarandet ,enligt uppfinningen erhalles en likformig forslitning av siktbordet, pa grund av att de olika delarna av siktbordet suceessivt foras I narheten av den punkt, vid vilken strain-mama h&j a och dar foljaktligen for slitningen Or mest markant, och ocksa. dad& att under ett helt vary air siktbordet moter forst den ena sidan och sedan den andra sidan av varje spalt strommen ay vatska och partiklar. In carrying out a screening according to Vidarandet, according to the invention, a uniform wear of the screening table is obtained, due to the fact that the different parts of the screening table are successively lined near the point at which the strains h & j a and there consequently for the wear Or most marked, and also. dad & that under a completely vary air sight table moter first one side and then the other side of each column stream ay liquid and particles.

Rotationshastigheten for siktbordet kan vara myeket lag. Riktningsandring av stromningen vid varje del air siktbordet ager rum tva ganger under yarje komplett vary av bordet, vadat- tiden f Or ett komplett vary endast behker vara halften sO. lang som intervallet mellan stromriktningsandringarna vid den kanda typen ay anlaggningar, for att atminstone ett lika gynnsamt resultat skall uppnas. Det bar dessutom uppmarksammas, att ju langsammare vridningen av bordet Or, desto lagre kan pamatningshastigheten vara, for att en given stramningshastighet i forhallande till bordet skall erhallas far det skikt som ror sig i samma riktning som siktbordet, och desto mindre blir skillnaden mellan de skilda stramningsskiktens hastigheter i forhallande till siktbordet. The rotation speed of the sight table can be very low. The change of direction of the flow at each part of the air sight table takes place twice during each complete vary of the table, at which time a complete vary only needs to be half sO. long as the interval between the changes in current direction at the known type of plant, in order to achieve at least an equally favorable result. It should also be noted that the slower the rotation of the table Or, the lower the feed rate can be, in order to obtain a given tightening speed in relation to the table from the layer moving in the same direction as the sight table, and the smaller the difference between the different the speeds of the tightening layers in relation to the sight table.

Uppfinningen avser Oven en anordning for utforande av vitsiktningsforfarandet enligt uppfinningen, vilken anordning innefattar ett cylindriskt krokt siktbord bestaende av pa avstand fear' varandra parallellt med cylinderns axel anordnade stanger, anordningar for att bringa yatskan att stromma i konkav strain- 203 03 ningslinje utmed siktbordets inneryta oeh anordningar for att uppsamla separerat material och kanneteeknas darav, att siktbordet är utformat som en sluten cylinder (5), vilken under anvandning kontinuerligt eller intermittent kan vridas omkring sin axel och av att pamatningsanordningarna (11, 12, 13), vilka är anordnade inuti det eylindriska sikthordet, ar forsedda med tva symmetriskt placerade munstycken (13), vilka är riktade i varandra motsatta riktningar utefter siktbordet. The invention also relates to a device for carrying out the whitening screening method according to the invention, which device comprises a cylindrical curved screening table consisting of rods arranged at a distance from each other parallel to the axis of the cylinder, devices for causing the surface to flow in a concave line along the inner surface of the screening table. devices for collecting separated material and can be characterized in that the screen is designed as a closed cylinder (5), which during use can be rotated continuously or intermittently about its axis and by the feeding devices (11, 12, 13) which are arranged inside the cylindrical sight hord, are provided with two symmetrically placed nozzles (13), which are directed in mutually opposite directions along the sight table.

Forfaringssattet samt anordningen enligt uppfinningen skall i det foljande narmare beskrivas i anslutning till bifogade ritning, i vilken fig. 1 är ett vertikalt tvarsnitt genom en siktningsanordning enligt uppfinningen, langs linjeni fig. 2'; fig. 2 är ett vertikalt tvarsnitt langs linj eni fig. 1; fig. 3 Sr ett vertikalt tvarsnitt av en annan siktningsanlaggning langs linj en III—III i fig. 4; fig. 4 Sr ett vertikalt tvarsnitt langs linjen i fig. 3; fig. 5 visar en detalj av ytterligare en annan siktningsanordning enligt uppfinningen; fig. 6 visar en del av anordningen i fig. 5 i storm' skala °eh fig. 7 visar samma siktningsanordning sedd fran hoger i fig. 6. The method set and the device according to the invention will be described in more detail below in connection with the accompanying drawing, in which Fig. 1 is a vertical cross-section through a screening device according to the invention, along the line in Fig. 2 '; Fig. 2 is a vertical cross-sectional view taken along line 1 of Fig. 1; Fig. 3 is a vertical cross-section of another screening plant taken along line III-III in Fig. 4; Fig. 4 is a vertical cross-section along the line of Fig. 3; Fig. 5 shows a detail of yet another screening device according to the invention; Fig. 6 shows a part of the device in Fig. 5 on a storm scale, and Fig. 7 shows the same screening device seen from the right in Fig. 6.

Den i fig. 1 och 2 visade siktningsanordningen bestar av ett hOlje 1 med en bottendel 2 och en avloppsledning 3 och av en buy 4, vilken Sr fastskruvad vid bottendelen. Inuti holjet är ett cylindriskt siktbord 5 bestaende av stanger 6 parallella med cylinderns axel och fastsatta radian ringar 15 roterbart monterat mellan styrrullar 7, varav den ena kan vridas av en motor 8 via en reduceringsvaxel monterad i ett vaxelhus 9. Stangerna aro mycket smala och besta av trad med rektangular eller trapetsformad tyarsektion. Under drift vrides cylindern 5 kontinuerligt °eh med konstant hastighet. Det är emellertid mojligt att alternativt anvanda en reduceringsaxel riled en drivmekanism av den typ som exempelvis anvandes vid rakneverk, i gas-, elektricitets- och vattenmatare, i vilken efter ett hell vary av ett hjul ett efterfoljande hjul hringas att utfora bara en del av ett vary, sa att siktbordet vrides stegvis. En pamatningsanordning 10 stracker sig in i siktcylinderns inre nara bottnen av densamma. Denna pamatningsanordning omfattar en tillforselledning 11 ansluten med hjalp av anslutningsstycken 12 till en spridare 13 med tva spaltliknande pamatningsmunstyckenvilka aro riktade i motsatta riktningar och tangentiellt i forhallande till siktbordets inneryta och sh utformade att en till pamatningsanordningen tillford suspension streommar ut ur dessa munstycken pa siktcylinderns inre yta som tva. skikt. En anordning 14 far utmatning av overfraktionen (dys. den fraktion som ej pas- serar genom siktbordet) Sr monterad ovanfor pamatningsanordningen 10 inuti cylindern 5, sS att vid en forutbestamd pamatningshastighet lamnar overfraktionsmaterialet siktbordet och faller ner i utmatningsanordningen 14, sasom visas med pilar i fig. 1. Utmatningsanordningen 14 liar en sluttande botten, sá att Overfraktionsmaterialet flyter bort ur cylinderns inre. Om sa 6nskas kan ett stralror 17 (markerat med streckade linjer i fig. 2) vara monterat over siktbordets 5 hogsta punkt. The screening device shown in Figs. 1 and 2 consists of a cover 1 with a bottom part 2 and a drain line 3 and of a buy 4, which Sr is screwed to the bottom part. Inside the housing, a cylindrical screen 5 consisting of rods 6 parallel to the axis of the cylinder and fixed radian rings 15 is rotatably mounted between guide rollers 7, one of which can be rotated by a motor 8 via a reduction shaft mounted in a gear housing 9. The rods are very narrow and of trad with rectangular or trapezoidal thyr section. During operation, the cylinder 5 is rotated continuously at a constant speed. However, it is possible to alternatively use a reduction shaft riled by a drive mechanism of the type used, for example, in razors, in gas, electricity and water feeders, in which after a successful variation of a wheel a subsequent wheel is rotated to perform only a part of a vary, so that the sight table is rotated step by step. A feeder 10 extends into the inner near bottom of the screen cylinder. This feeding device comprises a supply line 11 connected by means of connecting pieces 12 to a spreader 13 with two gap-like feeding nozzles which are directed in opposite directions and tangentially in relation to the inner surface of the sight table and are designed to have a suspension supplied to the feeding device. as two. layer. A device 14 discharges the overfraction (i.e. the fraction which does not pass through the screen) is mounted above the feed device 10 inside the cylinder 5, so that at a predetermined feed rate the overfraction material leaves the screen and falls into the discharge device 14, as shown by arrows in Fig. 1. The discharge device 14 has a sloping bottom, so that the overfraction material flows away from the interior of the cylinder. If desired, a radiator tube 17 (marked with dashed lines in Fig. 2) can be mounted above the highest point of the sight table 5.

Siktningsanordningen fungerar pa foljande satt. Den till pamatningsanordningen 10 tillforda suspensionen strommar flan spridarmunstyckena 13' med en forutbestamd hastighet, vilken till en del Sr hestamd av suspensionens koncentration. och viskositet, ut langs siktbordets inneryta i tva skikt, Tars stromningslinjer aro vinkelrata mot stangerna 6. Samtidigt wider sig siktbordet langsamt -omkring sin axel. Pamatningshastigheten valjes med hansyn till vridningshastigheten av bordet, sd att med sakerhet hastigheten i forhallande till siktbordet for det stromningssldkt som har samma rorelseriktning som siktbordet, Sr tillracklig for att astadkomma en separering av de partiklar, som aro av storleksordningen halften sd stora som bred-den av spalterna mellan stangerna. Nar suspensionen strommar uppat langs sidan av siktcylindern, stromma vatska och partiklar med en storlek under separeringsstorleken genom spalterna mellan stangerna, sa att stromningsskikten bli tunnare. Eventuellt lamnar det aterstaende materialet siktbordet under inverkan av tyngdkraften och faller i parabaliska banor ned i utmatningsanordningen 14. Vid en tillrackligt hog pamatningshastighet karma skikten till och med stota samman vid eller nara cylinderns hogsta punkt. Underfraktionen rnatas ut genom ledningen 3. Anordningen Or speciellt limpad for separering av tvattsuspensioner i kol- och malmtvatterier och for separering av cementslam. The screening device works in the following way. The suspension supplied to the feeding device 10 flows from the spreading nozzles 13 'at a predetermined speed, which to some extent depends on the concentration of the suspension. and viscosity, out along the inner surface of the sight table in two layers, Tars flow lines are perpendicular to the rods 6. At the same time, the sight table widens slowly - around its axis. The feed rate is selected with regard to the rotational speed of the table, so that with certainty the speed in relation to the sight table of the flow type having the same direction of movement as the sight table, is sufficient to effect a separation of the particles of the order of half as large as the width. of the gaps between the bars. When the suspension flows upwards along the side of the screen cylinder, liquid and particles of a size below the separation size flow through the gaps between the rods, so that the flow layers become thinner. Optionally, the remaining material leaves the sight table under the influence of gravity and falls in parabular paths down into the discharge device 14. At a sufficiently high feed rate, the karma layers even collide at or near the highest point of the cylinder. The subfraction is discharged through line 3. The device Or specially glued for separation of wash suspensions in coal and ore quarries and for separation of cement sludge.

Vid den i fig. 3 och 4 visade utforingsformen ay uppfinningen, varvid de delar som motsvara delar i fig. 1 och 2 aro fOrsedda med samma hanvisningsbeteekningar som i dessa figurer, Or pamatningsanordningen 10 anordnad nara den Owe delen av siktcylindern 5. Delta arrangemang erbjuder den fordelen_ att en nagot lAgre pamatningshastighet Sr tillracklig, eftersom tyngdkraften bidrager till stromningen langs siktytan. For att bortfora tiverfraktionen Or siktcylindern. 5 placerad med sin rotationsaxel i en liten. vinkel mot horisontalplanet oeh cylinderns ena ande Sr forsedd med en konisk kant 18. En smarre -nackdel med denna anordning gentemot den som visas i fig. 1 och 2 Or, att som ett resul- 4203 0 tat av att tyngdkraften verkar pa suspensionen kommer riktningen av stramningsskikten att avvika nagot fran den. riktning i vilken de matas ut pa separeringsbordet, dvs. vinkelratt mot siktstangerna. Enbart for separering av vatska och partiklar ar det jute sarskilt viktigt att stromningsskiktets riktning fir exakt vinkelrat mot siktstangerna och vid hog stramningshastighet ar avvikelsen forsumbart liten. In the embodiment of the invention shown in Figs. 3 and 4, wherein the parts corresponding to parts in Figs. 1 and 2 are provided with the same reference numerals as in these figures, the feeding device 10 is arranged near the Owe part of the sight cylinder 5. Delta arrangements offer the advantage_ that a slightly lower feed rate is sufficient, since gravity contributes to the flow along the screen surface. To remove the tiver fraction Or the sight cylinder. 5 placed with its axis of rotation in a small. angle to the horizontal plane and one end of the cylinder Sr provided with a conical edge 18. A minor disadvantage of this device compared to that shown in Figs. 1 and 2 is that as a result of gravity acting on the suspension, the direction of the tightening layers to deviate slightly from it. direction in which they are discharged on the separation table, i.e. angle steering wheel towards the sight bars. For the separation of liquid and particles only, it is particularly important that the direction of the flow layer is exactly perpendicular to the sieve rods and at high flow rates the deviation is negligibly small.

Denna nackdel undvikes vid den i fig. 5-7 visade anordningen. Aven vid den i dessa figurer -visade anordningen Ar siktcylindern 5 placerad horisontellt och en anordning 19 ar monterad Over den nedre delen av cylindern -oda anardnad att skjuta de fasta partiklarna som fasthallas pA siktbordet ut frail detta och over kantenDenna anordning tjanar sam- tidigt till att rensa spalterna mellan stangerna 6. Anordningen bestar av en rorlig borste, vars horst 20 Tara sig ner i spalterna och sedan uppat under borstens rorelse. Borstens drivmekanism ar kopplad till drivmekanismen for siktoylindern 5. Borsten 19 ar vid vardera anden fastad till en axel as, vilken ar roterbart lagrad i hal i ett par skivor 21. Skivorna 21. Arc fastsatta vid en axel 31 lag--red i lager 21 Nar axeln 31 vrides av drivanardningen (icke visad) utfi3r borsten en svepande rorelse langs bottnen av siktbordet for varje vary av skivorna 21. Borstert 20 dim sig parallellt med stangerna 6 i spalterna mellan stangerna °eh skjuta framat oth uppat alla fasta partiklar, som finnas i spalterna. This disadvantage is avoided with the device shown in Figs. 5-7. Also in the device shown in these figures, the screen cylinder 5 is placed horizontally and a device 19 is mounted over the lower part of the cylinder. to clear the gaps between the rods 6. The device consists of a movable brush, the horn of which rises into the gaps and then upwards during the movement of the brush. The drive mechanism of the brush is coupled to the drive mechanism of the sight cylinder 5. The brush 19 is attached at each end to a shaft axis, which is rotatably mounted in a slide in a pair of discs 21. The discs 21. Arc attached to a shaft 31 layer - red in layer 21 When the shaft 31 is rotated by the drive device (not shown), the brush makes a sweeping movement along the bottom of the sight table for each of the discs 21. The brush 20 dims parallel to the bars 6 in the gaps between the bars and pushes forward and upwards all solid particles present. in the columns.

PA axeln 311 ar ett koniskt kugghjul 23 fastsatt, som wider en skiva 27 via ett koniskt kugghjul 24, en axel 32, koniska kugghjul 25 och 26 samt en axel 33. Skivan 27 ar forsedd med en utskjutande ansats 28, som far varje vary av skivan kommer i kontakt med en tand pa en sparring 29 fastsatt pa en skiva 30. Denna sparring ar fastsatt vid en axel 34, ph vilken en av styrrullarna 7 fOr eylindern 5 ar monterad. Foljaktligen. medf or en kontinuerlig vridning av axeln 31 en kontinuerlig cirkelformad riirelse av borsten 19 och en stegvis rorelse av siktcylindern 5. En fj aderpaverkad hake 37 samverkar med sparringen 29 och hindrar ski-van 30 att vrida sig baklanges. Attached to the shaft 311 is a bevel gear 23 attached to a disc 27 via a bevel gear 24, a shaft 32, bevel gears 25 and 26 and a shaft 33. The disc 27 is provided with a projecting shoulder 28, which has a variety of the disc comes into contact with a tooth on a sparring 29 fixed to a disc 30. This sparring is fixed to a shaft 34, ph which one of the guide rollers 7 for the cylinder 5 is mounted. Consequently. a continuous rotation of the shaft 31 results in a continuous circular movement of the brush 19 and a stepwise movement of the sight cylinder 5. A spring-actuated hook 37 cooperates with the sparring 29 and prevents the disc 30 from rotating backwards.

Den i fig. 5-7 visade rensningsanordningen for siktbordet ar endast visad som ett exempel. Vilken som heist annan lamplig rensningsanordning kan alternativt anvandas och rensningsanordningen kan utfora en annan rorelse och dess rorelse kan pa annat satt vara samordnad med cylinderns r8relse. The cleaning device for the sight table shown in Figs. 5-7 is only shown as an example. Any other suitable cleaning device can alternatively be used and the cleaning device can perform a different movement and its movement can otherwise be coordinated with the movement of the cylinder.

Det ar joke vasentligt vid foreliggande uppfinning, att ,siktningen utfores enligt den me-tad sona beskrives i den svenska patentskrif ten 158 671, daunt uppfinningen i forsta hand ar avsedd for anvandning i forbindelse med denna xnetod. Sam redam papekats kan ett siktbord tillverkat av en perforerad platta ocksa anvandas. Vidare behiava jute de anvanda stromningshastigheterna Tara de som fareskrivas vid metoden enligt den namnda svenska patentskriften, for att vissa fOrdelar skola erhallas genom anvandandet av forf aringssattet eller anordningen enligt foreliggande uppfinning. It is essential in the present invention that the screening is carried out according to the method described in Swedish patent specification 158 671, since the invention is primarily intended for use in connection with this method. Sam redam papekats, a sight table made of a perforated plate can also be used. Furthermore, the flow rates used need to be those which are hazardous in the method according to the said Swedish patent specification, in order that certain advantages may be obtained by the use of the feed set or device according to the present invention.

Claims

Patent claim:

A process for water sieving a starting material containing solid particles, so that fractions of particles of different sizes are separated from each other or so. that the liquid is separated from the particles, a liquid in which the particles are mixed being caused to flow along the inside of a cylindrical curved sight table consisting of spaced apart rods parallel to the axis of the cylinder, characterized in that the liquid with the particles is caused to flow and two. layers with concave flow lines and with opposite, towards angled rods substantially perpendicular, directions of flow while the sight table is continuously or intermittently rotated about its axis in a directional ping.

2. A process according to claim 1, characterized in that the flow rate for each layer is selected so. in relation to the inner surface of the sight table, that it is always at least equal to the velocity at which the proximal particle size of the subfraction obtained is not greater than half the width of the gaps between the bars in the sight table.

Water screening device according to the method of claim 1-2 comprising a cylindrical curved screening table consisting of rods arranged at a distance from each other parallel to the axis of the cylinder, devices for causing the liquid to flow in a concave flow line along the inner surface of the screening table and devices for collecting separated material. , characterized in that the sight table is designed as a closed cylinder (5), which during use can be rotated continuously or intermittently about its axis and in that the feeding devices (11, 12, 13), which are arranged inside the cylindrical sight table, are provided with two symmetrically placed nozzles (13), which are directed in opposite directions along the sight table.

4. A water screening device, according to patent claim 3, characterized in that it comprises a device (14) located at the upper part of the screen table for collecting particles with a size above the separation size, which falls from the lowest part of sight drill it.

Water screening device according to claim 3, characterized in that the means (10) for causing the liquid to flow are arranged to cause the liquid to flow down the inner surface (5, Fig. 3) of the screen cylinder, such that a cleaning device (19) is arranged for cleaning. the lowest part of the screen cylinder (5) to which the flows are directed, which cleaning device comprises a brush-like means (20) and means for imparting to the brush such a movement that its brush moves along the gaps between the rods (6) and the lowest part of the screen cylinder. .

Windscreen screening device according to patent claim 5, characterized in that the movement of the cleaning device (19) is coordinated with the movement of the screening cylinder (5). Request publications: Patents treat Germany 945 831, 948 141.