SE191162C1

SE191162C1 -

Info

Publication number: SE191162C1
Authority: SE
Publication date: 1964-01-01

Description

Uppfinnare: F J Fontein och C W J van Koppen Prioritet begard frein den 22 april 1960 (Nederlanderna) Foreliggande uppfinning avser ett forfarande for vatsiktning av fasta partiklar samt en apparat for utforande av detta fOrfarande. Inventors: F J Fontein and C W J van Koppen Priority claimed on April 22, 1960 (The Netherlands) The present invention relates to a process for water sieving solid particles and to an apparatus for carrying out this process.

Pet är val kant, att vatsiktning kan anvandas antingen for att Iran ett av partiklar be- staende utgangsmaterial avskilja en finfraklion bestaende helt eller till storsta delen av partiklar under en bestamd storlek eller for att fran en suspension av vatska och fasta partiklar franskilja vatskan. I det f5rsta fallet kan utgangsmaterialet siktas sâ, att samtidigt en grovfraktion erhalles, vilken helt eller till stOrsta delen bestar av partiklar Over namnda bestamda storlek. The point is that water sieving can be used either to separate a fine fraction consisting of wholly or for the most part from particles of a certain size from Iran, a particle consisting of particles, or to separate the liquid from a suspension of liquid and solid particles. In the first case, the starting material can be sieved so that at the same time a coarse fraction is obtained, which consists wholly or for the most part of particles above the specified size.

Pet ãr majligt att utfOra en vatsiktning genom att lata partiklarna och vatska stromma langs ena sidan av ett siktbord. Speciellt hdnvisas harvid till det svenska patentet 158 671, i vilket metoder for vatsiktning av fasta partiklar beskrivas, vilka vasentligen bestã dari, att partiklarna uppblandas i en vatska, vilken bringas att stromma som ett skikt langs den konkava sidan av ett siktbord, vilket bestar av pa avstand Iran varandra anordnade stanger eller av en perforerad plat (dock foretradesvis av avstand anordnade stanger) och som är bojt i stromningsriktningen, °eh varvid stromningshastigheten samt storleken av och avstandet mellan oppningarna i siktbordet aro sa valda, att vatska eller vatska tillsammans med partiklar strommar genom Oppningarna pa 'grand: av - den .kinetiska energin och late eller blatt obetydligt.pa grund av gravitationskraften.- Dessa metoder besitta .flora fOrdelar. - gentemot tidigare anVanda vatsiktningsmetoder, speciellt darigenom, att det blir mojligt. 'att sikta partiklar ekonomiskt ned till enStorlek, -som ãrviiseatiigtmindre an- 1 ram--rochAill och riled mindre änO,5mm, .utan att ,sikhor- -det tappes_tilL eftersorn detattivat- ja strOmningsforhallandena sadana, alt den maximala partikelstorleken i den underfraktion (dvs. den fraktion som passerar genom siktbordet), som erhalles vid separering av en blandning av partiklar i fraktioner med olika storiekar, inte är vasentligt storre an hal-va storleken oppningarna i siktbordet matt i stromningsriktningen. For att utfora dessa siktningsforfaranden matas materialet till siktbordet vanligen med en hastighet av minst 0,5 m/sek. Under vissa omstandigheter kan matningshastigheten dock vara avsevart hog-re an denna. It is possible to perform a water screening by letting the particles and liquid flow along one side of a screening table. Reference is made in particular to the Swedish patent 158 671, in which methods for water sieving of solid particles are described, which essentially consist 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 at a distance from each other rods or of a perforated plate (though preferably spaced apart rods) and which are bent in the direction of flow, ° eh whereby the flow rate and the size and distance between the openings in the sight table are so selected that flows through the openings on the grand: of - the .kinetic energy and slow or blatantly insignificant. because of the gravitational force.- These methods possess .flora advantages. - compared to previously used water screening methods, especially in that it becomes possible. 'to aim particles economically down to aSize, -as ãrviiseatiigtsmaller an- 1 frame - rochAill and riled less than0, 5mm, .without, sikhor- -it tappes_tilL eftersorn detattivat- ja strOmingsforhallandena sadana, alt the maximum particle size in the subfraction ( i.e. the fraction passing through the sight table), which is obtained by separating a mixture of particles into fractions of different sizes, is not substantially larger than half the size of the openings in the sight table matt in the flow direction. To perform these screening procedures, the material is usually fed to the screening table at a speed of at least 0.5 m / sec. Under certain circumstances, however, the feed rate may be considerably higher than this.

Uppfinningen avser en apparat for vatsiktfling, vilken ocksa är avsedd for att anvandas for vatsiktning genom att det material som skall siktas far stromma langs sikten. Apparaten enligt uppfinningen liar en xnycket hog kapacitet. The invention relates to an apparatus for water screening, which is also intended to be used for water screening by allowing the material to be screened to flow along the screen. The apparatus according to the invention has a rather high capacity.

Enligt foreliggande uppfinning innefattar en apparat lamplig for valsiktning av fasta partiklar en eller flera siktar, vilka aro sd utformade och vid itera siktar sa sammanfogade, att en inre halighet avgransande siktvagg med runt vaggens omkrets sig kontinuerligt _strackande oppningar bildas, genom vilken halighetsvatska ()eh partiklar kan bringas att pus sera Iran halighetens ,ena anda till dess andra anda, varvid en eller flera tilledningar for vatska wit partiklar leda in i namnda )44- lighet genom dess ena ancle tilledningarnas form samt formen pa sikten resp, siktarnaär sadaii att, dO. vatska med dari uppblandade eller; suspenderade fasta partiklar niatas gefern niinanda tilledning resp. tillecinhvar med en lamp lig hastighet, etk vAtskeskikt bildas, vilket tacker hela eller,Osentligen. bpja siktvagg och striinunar Wigs donna sdsona en ,entiet i riktning.fran namnda end; anda,Av varvid vAtska-mectiArtikliat avg,ar lexigat,,silqvaggeri Uteftkg. -hda,,dess kits 2— — och partiklar, vilka icke passera genom siktvaggen, stromma ut genom halighetens andra ande. According to the present invention, an apparatus suitable for selective screening of solid particles comprises one or more sieves, which are so-formed and at iterated sieves so joined together that an inner cavity defining sieve wall with continuously extending apertures around the circumference of the cradle is formed, through which halide water () eh particles can be caused to pus sera Iran halality, one spirit to its other spirit, whereby one or more leads for liquid white particles lead into the said) 44- similarity through its one ankle leads form and the shape of the sight resp, the viewer sadaii that, dO . vatska with dari mixed or; suspended solids niatas gefern niinanda tilledning resp. tillecinhvar with a lamp lig velocity, a liquid layer is formed, which thanks the whole or, Essentially. bpja sight wall and striinunar Wigs donna sdsona one, entiet in direction.from the said end; anda, Av varvid vAtska-mectiArtikliat avg, ar lexigat ,, silqvaggeri Uteftkg. -hda ,, its kits 2— - and particles, which do not pass through the screen, flow out through the second spirit of the halite.

Uppfinningen innefattar ocksa metoder for vatsiktning, vid vilka ovannamnda apparat anvandes, antingen f5r att fran utgangsmaterial av partiklar avskilja fraktioner air partiklar med olika storlekar eller for att fran en vatska, i vilken fasta partiklar aro uppblandade eller suspenderade, avskilja vatska. mom vissa industriella omraden, dar vatsiktning av material utnyttjas, är det onskvart att undvika, att materialet kommer i kontakt med atmosfaren och apparaten enligt foreliggande uppfinning kan enkelt utforas sa, att detta krav uppfylles, Tnedan materialen vatsiktas. Saledes kan de,n halighet, som avgransas av sikten resp. siktarna i apparatep enligt uppfinningen, anslutas till en behallare eller annan kalla for en inert gas. Det är ocksa mojligt att ansluta en apparat enligt uppfinningen till en tryckgaskalla, sa att siktningsforfarandet kan utf5ras vid ett tryck Over atmosfartrycket. Detta gOr det mojligt att kontrollera separeringsgraden far partiklarna. The invention also includes methods of water sieving in which the above-mentioned apparatus is used, either to separate fractions of particles of different sizes from starting material of particles or to separate liquid from a liquid in which solid particles are mixed or suspended. In certain industrial areas, where water screening of materials is used, it is unavoidable to avoid the material coming into contact with the atmosphere and the apparatus of the present invention can be easily designed so that this requirement is met, before the materials are water screened. Thus, they can, n holiness, which is delimited by the sight resp. the screens in the apparatus according to the invention, are connected to a container or other cold for an inert gas. It is also possible to connect an apparatus according to the invention to a pressurized gas head, so that the screening process can be carried out at a pressure above atmospheric pressure. This makes it possible to control the degree of separation of the particles.

Sikten resp. siktarna i en apparat enligt uppfinningen kan besta av pa avstand fran varandra anordnade stanger sa placerade, att det strommande skiktet i alla punkter ror sig vinkelratt mot de underliggande stangerna. Alternativt kan en sikt resp. siktar bestaende air perforerad plat anvandas, varvid perforeringarna uteires av spaltliknande oppningar med langssidorna anordnade vinkelratt mot stromningsriktningen for vatskeskiktet. The sight resp. the screens in an apparatus according to the invention may consist of rods arranged at a distance from each other so placed that the flowing layer at all points moves perpendicular to the underlying rods. Alternatively, a sight resp. existing perforated plate is used, the perforations being formed by gap-like openings with the longitudinal sides arranged at an angle to the flow direction of the liquid layer.

En apparat enligt uppfinningen bestaende air en resp. flera siktar bestaende air stanger lampligt anordnade med avseende pa vatskeskiktets stromningsriktning kan anvandas for vatsiktning pa sa.dant satt, att vatska avb5jes air stangerna och flyter genom spalterna melIan stangema helt eller till storsta delen pa grund av dess kinetiska energi och ej eller endast obetydligt pa grund av gravitationskraften. Det är pa detta satt mojligt att separera en blandning av partiklar med olika storlek sa att den maximala partikelstorleken, vilken passerar genom siktspalterna, inte är vasentligt storre an halva spaltbreden. Pa liknande satt kan goda resultat uppnas med lampliga apparater enligt uppfinningen med en sikt resp. siktar bestaende av perforerad plat. An apparatus according to the invention consisting of air a resp. several sieves existing air rods suitably arranged with respect to the flow direction of the liquid layer can be used for water sieving in such a way that liquid is deflected by the air rods and flows through the gaps between the rods entirely or largely due to its kinetic energy and not or only insignificantly on due to the force of gravity. In this way it is possible to separate a mixture of particles of different sizes so that the maximum particle size, which passes through the sieve gaps, is not substantially larger than half the gap width. In a similar way, good results can be achieved with suitable devices according to the invention with a view resp. aims consisting of perforated plate.

Siktapparaten enligt uppfinningen är foretradesvis sã utformad, att den halighet som periferiellt avgransas av sikten resp. siktarna avsmalnar i riktning mot den anda, vid vilken de for stora partiklarna utstromma, varvid derma avsmalning kan aga rum utefter halighetens hela langd eller enbart utefter dess senare del. Allteftersom det strommande skiktet ror sig vidare genom namnda hang-, het eller siktkammaren, avtager skiktets tjocklek, pa grund av att vatska passerar ge nom sikten resp. siktarna. Om siktkammaren avsmalnar pa ovannamnt satt, reduceras minskningen i skikttjockleken sa, att den centrifugalkraft okar, vilken utovas pa de material som bildar skiktet, vilket ger till re sultat, att en Wine andel vatska och upp blandade partiklar strommar genom Opp ningarna, varigenom en torrare overfraktion kan erhallas. Detta Or Onskvart i alla de fall, dar det Or en fordel att fraktionen av for store partiklar, dvs. partiklar vilka icke passera genom sikten resp. siktarna, innehaller sa litet vatska som mojligt. Det bor emellertid papakas, att det är icke vasentligt att siktkammaren avsmalnar. Om siktkammaren skall vara avsmalnande, kan den lampliga avsmalningsvinkeln for erhallande air ett onskat resultat vid vane speciell matningshastighet latt bestammas med enkla prov. En variabel airsmalning kan ocksa. anvandas. Som exempel kan siktkammaren vara konsidal eller sfarisk eller delvis sfarisk. En speciell utforingsform av en siktningsapparat, vilken kommer att beskrivas i detalj i det foljande, innefattar en sfarisk siktenhet och denna apparat her den f8rdelen, att den kan reverseras i forhallande till Tnatningsanordningarna, sa att stromningsriktningen langs siktytan kan periodiskt vaxlas. Denna sfariska utformning samt mojligheten till reversering Or i princip avsedd att anvandas vid en sikt bestaende av pa avstand fran varandra anordnade stanger. I detta fall kan livslangden hos sikten forlangas genom den periodiska omkastningen air stromningsriktningen, vilken har till foljd, att forslitningen fordelas mellan motstaende sidor pa stangerna. Denna sfariska typ ay apparat har ocksa. den fordelen, att det material som skall siktas kan matas till siktkammaren i ett forhallandevis tjockt skick, eftersom skiktets tjocklek snabbt minskar, nOr skiktet strommar radiellt utat fran matningszo,nen. Detta minskar risken att inmatningsoppningen eller -oppningarna tap-pas till av speciellt grova partiklar. Vid utstromningsanden minskar siktkammarens diameter, vilket her de ovan nanuida fordelarna. The screening apparatus according to the invention is preferably designed in such a way that the hilt which is peripherally delimited by the screen resp. the sieves taper in the direction of the spirit in which the oversized particles flow out, this taper being able to take place along the entire length of the cavity or only along its later part. As the flowing layer moves further through the said hanging, hot or screen chamber, the thickness of the layer decreases, due to liquid passing through the screen resp. the sights. If the sieve chamber tapers in the above manner, the decrease in layer thickness is reduced so that the centrifugal force exerted on the materials forming the layer increases, resulting in a Wine proportion of liquid and mixed particles flowing through the openings, thereby a drier overfraction can be obtained. This Or Onskvart in all those cases, where it Or an advantage that the fraction of too large particles, ie. particles which do not pass through the sieve resp. the sights, contain as little liquid as possible. It should be noted, however, that it is not essential for the sieve chamber to taper. If the sieve chamber is to be tapered, the suitable taper angle for obtaining air can be a desired result at the usual special feed speed easily determined with simple tests. A variable air paint can also. used. As an example, the sieve chamber may be considal or spherical or partially spherical. A special embodiment of a screening apparatus, which will be described in detail in the following, comprises a spherical screening unit and this apparatus has the advantage that it can be reversed in relation to the sealing devices, so that the flow direction along the screening surface can be periodically switched. This spherical design and the possibility of reversal are in principle intended to be used in a screen consisting of spaced apart rods. In this case, the service life of the screen can be required by the periodic reversal in the direction of flow, which has the consequence that the wear is distributed between opposite sides of the rods. This spherical type ay apparatus also has. the advantage that the material to be screened can be fed to the screen chamber in a relatively thick condition, since the thickness of the layer decreases rapidly when the layer flows radially outwards from the feeding zone. This reduces the risk of the feed opening or openings being clogged by particularly coarse particles. At the outflow end, the diameter of the screen chamber decreases, which here are the above nanoid advantages.

Vid vissa utforingsformer av en apparat enligt uppfinningen innefattar siktenheten tre eller flera plana, med varandra sammanfogade siktar. En sadan apparat Or enkel och billig. I detta fall har den halighet, som aygransas av siktarna, foretradesvis ett regelbundet polygonalt tvarsnitt i vane plan yinkelratt mot centrumaxeln genom halighetens hada andar. I detta fall Oro matningsanordningarna sa. utforda, att det strommande skiktet bringas sadan rorelse att strOmningslinjen i vane punkt ligger i ett plan genom namnda centrumaxel f5r haligheten. In certain embodiments of an apparatus according to the invention, the screening unit comprises three or more planar, interconnected screens. Such a device Or simple and cheap. In this case, the slenderness, which is accentuated by the sieves, preferably has a regular polygonal cross-section in the usual plane perpendicular to the center axis through the hated spirits of the slatings. In this case, worry the feeders said. challenge, that the flowing layer is moved in such a way that the flow line at the usual point lies in a plane through said center axis of the cavity.

FOretradesvis innefattar emellertid apparaten en eller flera krokta siktar, vilka aygransa en radial-symmetrisk halighet, och I — 3 detta fall är det fordelaktigt att utfora matningsanordningarna sa, att vatskeskiktet bor- jar sin stromning med en tangentiell rorelse- komponent med avseende pa siktytan och fortsatter med en spiralformad rorelse langs siktkammaren. Pa detta salt beframjas det strOmmande skiktets vidhaftning till siktytan. Det bor emellertid observeras, att den roterande rorelsen tenderar till att ge en gig:lyre separering. Rada dessa faktorer maste darfor tagas i betraktande vid bestamning ay den tangentiella hastigheten. Preferably, however, the apparatus comprises one or more curved sieves which define a radial-symmetrical cavity, and in this case it is advantageous to design the feeding devices so that the liquid layer begins its flow with a tangential movement component with respect to the sieve surface and continues with a helical motion along the screen chamber. On this salt, the adhesion of the flowing layer to the screen surface is promoted. It should be noted, however, that the rotating motion tends to give a gig: lyre separation. These factors must therefore be taken into account when determining the tangential velocity.

Alternativt kan I stallet f8r en resp. flera siktar bestaende av stanger eller perforerad plat, siktvaggen i en apparat enligt uppfinningen utformas av en spirallindad trad, exempelvis en trad med rektanguldr, triangular eller trapetsformad tvarsektion. Alternatively, in the stable for a resp. several screens consisting of rods or perforated plate, the screen cradle in an apparatus according to the invention is formed by a spirally wound wire, for example a wire with a rectangular gold, triangular or trapezoidal cross section.

I det foljande skall uppfinningen narmare beskrivas I anslutning till bifogade ritning, vilken sasom exempel visar olika utforingsformer av en apparat enligt uppfinningen. Fig. 1 visar darvid ett langdsnitt genom en utf6- ringsform. Fig. 2 visar schematiskt ett langdsnitt genom en a,nnan utforingsform. Fig. 3 visar schematiskt ett langdsnitt genom ytterligare en utforingsform. Fig. 4 visar en del av sikthuset i fig. 3 sett fran sidan. Fig. 5 visar ett tvarsnitt av en variant av ett siktbord. Varandra motsvarande delar i ritningens olika figurer aro f6rsedda med samma ha,nvisningsbeteckningar. In the following, the invention will be described in more detail in connection with the accompanying drawing, which as an example shows different embodiments of an apparatus according to the invention. Fig. 1 then shows a longitudinal section through an embodiment. Fig. 2 schematically shows a longitudinal section through another embodiment. Fig. 3 schematically shows a longitudinal section through a further embodiment. Fig. 4 shows a part of the screen housing in Fig. 3 seen from the side. Fig. 5 shows a cross section of a variant of a sight table. Corresponding parts in the various figures of the drawing are provided with the same reference numerals.

I fig. 1 bestar sikten 1 av en konisk siktvagg 2 sammansatt av pa lika stora avstand Iran varandra anordnade stanger 3, vilka aro bojda till ringar och ha en vdsentligen rektangular, triangular eller trapetsformad tvarsektion. Dessa stanger 3 aro fastsatta yid lister 4. Med hjalp av listerna 4 och bultar 5, dr sikten ansluten till den cylindriska anden 6 pa ett r5r 7, vilket bildar en tillforselledning for det material som skall siktas. Sikten omgives ay ett hus 9 fastsatt med hjalp ay bultar 10 till en plat 8 vilken pa lampligt satt, exempelvis medelst svetsning, dr ansluten till den cylindriska delen 6. Detta hus är forsett med en utstromningsledning 10 for underfraktionen. Till underdelen pa sikten 1 ar en utstromningsledning 11 for overfraktionen ansluten, vilken ledning passerar genom huset 9. Koncentriskt med inmatningsandan pa sikten 1 ar en kropp 12 placerad i den cylindriska delen 6. Denna kropp kan fOrskjutas axiellt i den cylindriska delen 6, sa att bredden hos den ringformade inmatningsspalten 22 kan justeras. Fenor 14 aro fastsatta mid kroppen 12 for styrning av inmatningen av det material som skall siktas. Kroppen 12 kan f5rskjutas medelst en slang 15, vilken passerar genom ett styrorgan 16 gjutet I eller fastsvetsad Yid tilledningsrOret 7 och ar tatad mot omgivningen med hjalp av en packning 18 och en ring 17. Stangen kan vara fastsatt mid kroppen 12 medelst en skruv ganga. Forskjutningen ay kroppen 12 och stangen 15 kan ske pa lampligt kant satt. In Fig. 1, the screen 1 consists of a conical screen wall 2 composed of equally spaced rods 3, which are bent into rings and have a substantially rectangular, triangular or trapezoidal cross-section. These rods 3 are attached to the strips 4. By means of the strips 4 and bolts 5, the screen is connected to the cylindrical spirit 6 on a tube 7, which forms a supply line for the material to be screened. The screen is surrounded by a housing 9 fixed by means of bolts 10 to a plate 8 which is suitably mounted, for example by welding, there connected to the cylindrical part 6. This housing is provided with an outflow line 10 for the subfraction. Connected to the lower part of the screen 1 is an outflow line 11 for the overfraction, which line passes through the housing 9. Concentrically with the feed spirit on the screen 1, a body 12 is placed in the cylindrical part 6. This body can be displaced axially in the cylindrical part 6, so that the width of the annular feed slot 22 can be adjusted. Fins 14 are attached to the body 12 to control the feed of the material to be screened. The body 12 can be displaced by means of a hose 15, which passes through a guide member 16 cast in or welded to the lead pipe 7 and is attached to the environment by means of a gasket 18 and a ring 17. The rod can be fixed to the body 12 by means of a screw thread. The displacement of the body 12 and the rod 15 can take place on a suitable edge.

Kroppen 12 ar fOrsedd med en kanal 19, vil- ket star i fOrbindelse med en kanal 20 i stangen 15, vilken kanal antingen kan mynna i den omgivande atmosfaren eller vara ansluten till en icke visad ledning, genom vilken gas kan tillforas eller utsugas frau utrymmet inuti sikten 1. Detta gor det bl. a. mojligt att pA verka separeringsgraden. The body 12 is provided with a channel 19, which communicates with a channel 20 in the rod 15, which channel can either open into the surrounding atmosphere or be connected to a line (not shown), through which gas can be supplied or extracted from the space. inside the sight 1. This makes it, among other things. a. possible to affect the degree of separation.

Styrfenor 21 aro anordnade pa insidan av tillforselledningen 7, sa. att en jamn fOrdel- ning ay den tillforande suspension erhalles utefter den spalt 22, i vilken tillforselledninge,n mynnar. Guide fins 21 are arranged on the inside of the supply line 7, so. that an even distribution ay the supply suspension is obtained along the gap 22 in which the supply line, n opens.

Det kan vara lampligt att bibringa suspensionen aven en liten tangentiell hastighet, nar den matas in pa sikten, for att darigenom fOrhindra att vatskeskiktet forlorar kontakten med sikten. Detta kan intraffa om sikten ar cylindrisk eller kraftigt avsmalnande. For att ge denna tangentialhastighet kan fenorna 14 ha en lamplig form eller placering. It may be convenient to impart the suspension even at a small tangential speed when it is fed into the screen, in order to prevent the liquid layer from losing contact with the screen. This can occur if the visibility is cylindrical or sharply tapered. To provide this tangential velocity, the fins 14 may have a suitable shape or location.

Det kan ocksa vara ay betydelse att bibringa det strommande skiktet en tangen- tiell hastighet, da. siktbordet bestar ay en trad med lamplig sektion, som har lindats till spiralform, sA att ett koniskt eller cylindriskt siktbord erhalles. I detta fall valjes en sadan tangentiell hastighet, att suspensionen strOmmar i en riktning, som Ar va.sentligen vinkelrat mot den lindade tra den. It may also be of importance to impart a tangential velocity to the flowing layer, then. the sight table consists of a wire with a lamp section, which has been wound into a spiral shape, so that a conical or cylindrical sight table is obtained. In this case, such a tangential velocity is selected that the suspension flows in a direction which is substantially perpendicular to the wound thread.

Den i fig. 2 schematiskt visade sikten 1 dr konoidal, dvs. den är bojd inte bara i tvarplanen utan ocksa i langdplanen. The view 1 dr conoidally shown in Fig. 2 schematically, i.e. it is bent not only in the transverse plane but also in the longitudinal plane.

Fig. 3 visar en sikt 1, vilken avgransar en vasentligen sfarisk kammare och som kan vandas, sa att inmatnings- och utmatnings- oppningarna i kammaren byta plats. Suspensionen 11111 Ores genom en stor inmatnings- spalt, varigenom forhindras, att denna spalt tappes till ay i suspensionen eventuellt uppblandade stOrre klumpar av partiklar. Da sus- pensionen strommar bort Iran inmatningsanden blir suspensionsskiktet tunnare och siktbordets area storre, sd'. att en god siktverkan kan erhallas. Efter det att skiktet passerat kammarens storsta diameter, kommer skiktet att tendera att bli tjockare igen vilket ger som resultat att trycket mot siktbordet 8kar och en praktiskt taget torr Overfraktion erhalles. Fig. 3 shows a screen 1, which delimits a substantially spherical chamber and which can be watered, so that the inlet and outlet openings in the chamber change location. The suspension 11111 Ores through a large feed-in gap, thereby preventing this gap from being drained to ay in the suspension any larger lumps of particles mixed in. As the suspension flows away from Iran's input spirit, the suspension layer becomes thinner and the area of the sight table larger, sd '. that a good visibility can be obtained. After the layer has passed the largest diameter of the chamber, the layer will tend to become thicker again, as a result of which the pressure against the screen table 8kar and a practically dry Overfraction is obtained.

Vid denna utforingsform ar sikten forsedd med spindlar 23 med handtag 24, vilka spindlar vilar pa st6d 25, vilka mid 26 kunna rotera i huset 7. Nedanfor spindlarna 23 finnas spalter 27 (visade med streckade linjer i figuren) i huset 7. I utstrOmningsledningen 11 kan en cylindrisk del 11' forskjutas med hjdlp av en stang 28. Om sikten skall vandas, sankes delen 11' och kroppen 12 hojes om sa erfordras. Sasom schematiskt visas i fig. 4, bringas stOden 25 i det med 25' betecknade laget, sd att spindlarna 23 sankas.i. spalterna. 4— — 27. Langden av dessa spalter är sadan, att sikten 1 nar ett Ifige sa langt under undersidan pa kroppen 12, att sikten kan vandas med hjalp av handtagen 24. In this embodiment the screen is provided with spindles 23 with handles 24, which spindles rest on supports 25, which centers 26 can rotate in the housing 7. Below the spindles 23 there are slits 27 (shown in broken lines in the figure) in the housing 7. In the outflow line 11 For example, a cylindrical part 11 'can be displaced by means of a rod 28. If the screen is to be watered, the part 11' is lowered and the body 12 is raised if necessary. As schematically shown in Fig. 4, the pillar 25 is brought into the layer denoted by 25 ', so that the spindles 23 are lowered. columns. 4— - 27. The length of these gaps is such that the screen 1 reaches a gap so far below the underside of the body 12 that the screen can be watered with the aid of the handles 24.

Fig. 5 visar tvarsnittet genom ett siktbord bestaende av med varandra hopfogade plana siktar, vilka kunna skaras ut frau siktar av det slag, som finnas tillgangliga i handeln. Det utrymme, som avgransas av siktarna, liar ett tvarsnitt som i varje plan bildar en regelbunden oktagon. Fig. 5 shows the cross-section through a screening table consisting of interconnected flat screens, which can be cut out from screens of the kind available in the trade. The space delimited by the screens has a cross section which in each plane forms a regular octagon.

Claims

Patent claim: A process for water sieving a starting material of solid particles, in which fractions of particles of different sizes are separated or liquid is separated from solid particles suspended or mixed in the liquid, characterized in that a sieving apparatus is used comprising one or more sieves, which form a lure halinity delimiting sieve wall with it along the circumference of the sieve wall continuously stretching openings, whereby liquid with dari mixed or suspended particles is caused to flow into said hollow from its one dude, sit to a liquid layer Midas, which thanks the whole or

1. substantially the entire said screen wall and which flows along the screen wall in the direction of the said one end of the cavity, wherein liquid resp. liquid with particles exits through the sieve along its entire circumference and particles which do not pass through the sieve flow out through the second spirit of the cavity.

2. A method according to claim 1, characterized in that the liquid is caused to flow along said screen wall in a layer of such thickness that a large part of the liquid flowing into the cavity emits through the openings in the screen wall.

3. A method according to any one of the preceding patent claims, characterized in that the openings in the screen wall are in the form of slits, and the liquid layer is caused to flow in such a way that its direction of flow over each gap is perpendicular to the longitudinal sides of the gap.

4. A method according to any one of the preceding patent claims, characterized in that the liquid is caused to flow so that at each point of the flowing layer the flow line lies in a plane through a central axis through the spirits of the cavity.

5. A method according to any one of the preceding claims, characterized in that said screen wall is bent so that it has a constant radius in each plane perpendicular to a dentrum axis through the spirits of the cavity, so that the cavity is radially symmetrical; varjam.-te the liquid is brought to flow so., - that the liquid layer flows along the sieve wall with a spiral-shaped movement :.

6. Apparatus for water sieving of solid particles according to the method according to any of the preceding patent claims, characterized in that it comprises one or more sieves so designed and joined at several sieves so that an inner halving delimiting sieve wall (2) is carried with it. along the circumference of the cradle continuously extending openings Midas, and one or more supply lines (6) are arranged to open in said cavity at its one end, the line resp. the shape of the line and the shape of the screen resp. the sieves are such that then liquid with mixed or suspended solid particles is supplied through the supply line resp. the lines at an appropriate speed, a liquid layer is formed, which thanks the whole or substantially the whole screen and flows along it in the direction of said one spirit of the cavity and liquid or liquid with particles emits through the screen along its entire circumference and particles which do not pass through the screen , tighten through the second spirit of holiness (11).

7. Apparatus according to claim 6, characterized in that the openings in the screen wall have the shape of gaps so arranged that the long sides of each gap draw substantially perpendicular to the direction of flow of the liquid layer.

Apparatus according to claim 6 or 7, characterized in that said screen cradle consists of one or more screens (1 '), which are curved with a constant radius in all planes perpendicular to a center axis through the two spirits of the cavity, sO. that the height of the radial symmetry risk.

9. Device according to patent claim 8, characterized in that the nd.mnda supply line resp. pipes are so designed that the resulting liquid layer flows in the direction from one end of the cavity with a helical movement.

10. Apparatus according to claim 8 or 9, characterized in that said slowness tapers in the direction of said second spirit (11).

11. Apparatus according to any one of patent claims 6-10, characterized in that the sight resp. the sieves which form the said sieve cradle are bent between the two spirits of the sieve, whereby the sieve resp. the concave sides of the sieves are directed towards the slenderness.

Apparatus according to any one of the patent claims 6 = 11, characterized in that most of the similarity delimited by the sight wall is spherical. (Fig. 3.) 13: Apparatus according to patent claim 12, can be concluded from the fact that the spirits of said hollow have the same or substantially the same diameter, and the sight unit is pivotally mounted. about an axis in such a way, that antingeii_ nfininda forsta or flatrinda .andra Ande-haligheten: kan. brought to - - cooperate with name.da supply line resp. management.

13. Apparatus according to claim 6 or 7, characterized in that it comprises three or more planar sieves, s. Joined together, that the cavity Mr delimited by them has a shape such that in each plane perpendicular to a central axis through the cavity of the cavity the individual the sights touch a common circle. (Fig. 5.)

Apparatus according to claim 14, characterized in that said hardness is tapered towards its other end.

15. Apparatus according to any one of claims 6-15, characterized in that said supply line resp. conduits open in an annular outflow opening formed by one edge of the sight unit and a body (12) arranged centrally in the corresponding spirit of the clearance delimited by the sight unit.

Apparatus according to any one of claims 6-16, cheek-drawn drive, that it of the sight resp. the sieves delimited the hilt is connected to a pressurized gas skull. Request publications: Patentskrifter frcin Sverige 158671; USA 1,063,991.