EP0472458B1 - Process for disaggregating agglomerated solid particles which are suspended in a liquid - Google Patents

Process for disaggregating agglomerated solid particles which are suspended in a liquid Download PDF

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Publication number
EP0472458B1
EP0472458B1 EP91402260A EP91402260A EP0472458B1 EP 0472458 B1 EP0472458 B1 EP 0472458B1 EP 91402260 A EP91402260 A EP 91402260A EP 91402260 A EP91402260 A EP 91402260A EP 0472458 B1 EP0472458 B1 EP 0472458B1
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EP
European Patent Office
Prior art keywords
venturi tube
liquid
passage
injector
tank
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EP91402260A
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German (de)
French (fr)
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EP0472458A1 (en
Inventor
Jacques Dollfus
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Orano Demantelement SAS
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Compagnie Generale des Matieres Nucleaires SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C19/00—Other disintegrating devices or methods
    • B02C19/06—Jet mills

Definitions

  • the invention relates to a method for disintegrating agglomerated solid particles which are in suspension in a liquid, as well as to a device implementing this method.
  • the method and the device according to the invention advantageously apply to the disaggregation of fines, that is to say solid materials of small particle size which are obtained, during the reprocessing of irradiated nuclear fuels, after dissolving the fuels cut in hot nitric solutions, then clarification of the nitric solutions.
  • fines whose chemical composition is based on zirconium, molybdenum, ruthenium and other metals entering the fuel structure, are present after clarification, for example in a pendulum centrifugal decanter, in the form of sludge or more or less solutions thick and more or less agglomerated.
  • the fines, which are highly irradiating are transferred by appropriate pipes to a vitrification site where they are included in a glass matrix, after having stayed in storage tanks in which they are constantly agitated, for example by means pulsers, for nuclear safety reasons.
  • the agglomerates constitute abrasive particles which create wear in particular in the curved parts of the transfer pipes.
  • the invention is particularly suitable for the disaggregation of the agglomerates contained in the highly irradiating fines obtained during the reprocessing of irradiated nuclear fuels, it is not limited to this application and can be used whenever 'It seems desirable to disaggregate agglomerated solid particles, suspended in a liquid, in particular to carry out the treatment of certain industrial effluents, for example in the chemical and food industries.
  • Documents GB-A-1 329 941 and GB-A-591 921 propose to reduce the size of solid particles by mixing them with a carrier gas which is circulated in a venturi tube.
  • the invention specifically relates to a method and a device for disaggregating agglomerated solid particles, which are suspended in a liquid, in order for example to eliminate any risk of formation of plugs during the transfer of these particles or any risk of blocking of any mechanism by agglomerated particles, as well as to reduce if necessary the abrasive nature of these particles.
  • the agglomerated solid particles By passing the agglomerated solid particles several times through a nozzle of the venturi tube type, these particles are subjected to a strong speed gradient in a radial direction. In other words, in a section perpendicular to the axis of the nozzle, the speed of movement of the fluid varies very significantly from the center to the periphery. At each passage, the agglomerated solid particles are therefore subjected to a very high shear force parallel to the axis of the nozzle, which has the effect of disaggregating the agglomerates conveyed by the liquid.
  • the liquid is circulated respectively from bottom to top and from top to bottom in a substantially vertical venturi tube. Tests have shown that the efficiency of the process is greater when the liquid circulates downwards inside the nozzle.
  • the invention also relates to a device for disaggregating agglomerated solid particles, suspended in a liquid, characterized in that it comprises a tank into which an inlet passage and an evacuation passage for the liquid containing the agglomerated solid particles, an injector and a venturi tube being mounted in this order in the tank, between the intake passage and the evacuation passage, as well as recycling means recycling part of the venturi tube liquid leaving this tube.
  • the venturi tube and the injector are arranged along a substantially vertical common axis, the injector being placed below the venturi tube and communicating with the intake passage through a chamber inlet formed in a lower part of the tank, the venturi tube having an upper outlet end which communicates with the discharge passage through an annular passage formed around the venturi tube, and a lower inlet end which communicates with the annular passage through holes formed in a partition and constituting said recycling means.
  • the venturi tube and the injector are arranged along a substantially vertical common axis, the injector being placed above the venturi tube and communicating with the intake passage by a outer annular passage formed around the venturi tube, the latter comprising a lower outlet end which opens out above a deflector and communicates with the discharge passage through a discharge chamber formed in a lower part of the tank, and an upper inlet end which communicates with the lower outlet end by the recycling means, the latter means comprising an inner annular passage and a deflector placed opposite the lower outlet end of the venturi tube.
  • a baffle system can be placed downstream of the venturi tube.
  • the reference 10 designates a horizontal concrete slab which separates an upper zone 12, accessible to man, from a lower cell 14 in which the dangerous liquids containing the agglomerated solid particles which are desired are treated. disaggregate.
  • a device 16 according to the invention is suspended from the slab 10 so as to be placed in the cell 14.
  • This device 16 comprises a cylindrical tank 18, of vertical axis, provided at its upper end with a flange 20 which rests on the slab 10 and is securely joined thereto, for example by screws 22.
  • the tank 18 is closed at its upper end by a cover 24 tightly fixed on the flange 20, for example by screws 25.
  • a ferrule 26 projects downwards, from the underside of the cover 24, coaxially with the tank 18 and inside of it. This ferrule 26 supports at its lower end, by means of screws 28, an ejector assembly generally designated by the reference 30.
  • This ejector assembly 30 comprises a body in three parts 31, 32, 33, centered on the vertical axis of the tank 18. These three parts include a lower part 31, an internal central part 32 and an external upper part 33.
  • the lower part 31 in the form of a disc, is fixed by screws 34 to the lower end of the internal central part 32. It comprises in its center, along the vertical axis of the tank 18, a convergent injector 36. L the lower end of the larger diameter of the injector 36 opens into an inlet chamber 38 formed in the lower part of the tank 18. An inlet passage 40, formed in a thicker part 18a of the wall of the tank 18 also opens into the intake chamber 38, in order to allow the introduction into this chamber of the liquid containing the agglomerated solid particles which it is desired to disintegrate. This liquid is injected under pressure into the device 16 by a pump (not shown), the injection pressure being for example at least equal to 300 kPa.
  • the internal central part 32 of the body of the assembly 30 comprises a lower portion 43 in the shape of a bell, under which the lower part 31 is fixed, and an upper portion forming a venturi tube 44.
  • a recycling chamber 42 is formed between said lower portion 43 in the shape of a bell and the lower part 32a.
  • the lower end of the venturi tube 44 arranged coaxially with the injector 36 and the tank 18, opens into the recycling chamber 42 above the injector 36.
  • the venturi tube 44 internally forms a lower zone d relatively short converging inlet 46 and a relatively long upper diverging outlet area 48.
  • the bell-shaped lower portion 43 On its outer surface, the bell-shaped lower portion 43 carries an O-ring seal 60 which cooperates sealingly with the inner surface of the thicker part 18a of the tank 18, above the mouth of the intake passage 40.
  • the intake chamber 38 is thus isolated from the rest of the tank 18.
  • the external upper part 33 of the body of the assembly 30 comprises a lower portion 49 in the form of a ring, fixed to the lower end of the ferrule 26 by the screws 28 and placed around the venturi tube 44.
  • This lower portion 49 in ring shape rests on the thicker part 18a of the tank 18, by means of two O-ring seals 62.
  • the outer upper part 32c further comprises, above the lower portion 49 in the form of a ring, a tubular portion 50 formed at its upper end, above the venturi tube 44, by a portion 51 in the form of a cap.
  • the tubular portion 50 is arranged coaxially around the venturi tube 44 and supports the latter by means of tie rods welded 53.
  • An annular passage 54 formed between the venturi tube 44 and the part 32c makes the upper end of the venturi tube communicate with an evacuation passage 58 formed in the thicker part 18a of the tank 18 and opening in the tank between seals 60 and 62.
  • Holes 64 formed in the horizontal upper partition of the bell-shaped lower part 43 make the lower end of the annular passage 54 communicate with the recycling chamber 42. These holes allow part of the fluid to be recycled to the inside of the venturi tube 44 as will be seen later.
  • the liquid containing the agglomerated solid particles which it is desired to disintegrate is introduced into the device through the intake passage 40, preferably at a pressure of at least 300 kPa.
  • the pressurized liquid admitted into the intake chamber 38 passes through the assembly 30 from bottom to top, passing successively through the injector 36 and through the converging 46 and diverging 48 zones of the venturi tube 44.
  • the flow of the liquid in the injector 36, then in the venturi tube 44 takes place at high speed.
  • the speed reached by the liquid is approximately 18 m per second.
  • the venturi tube 44 is added the induced flow resulting from the entrainment by this primary liquid of the liquid introduced into the recycling chamber 42 through the holes 64 Tests have shown that the induced flow is very close to the primary flow. Therefore, the flow of liquid passing through the venturi tube 44 corresponds to approximately 10 m3 per hour in the example cited above.
  • the liquid exiting at high speed from the upper end of the venturi tube 44 strikes the portion 51 in the form of a cap and descends through the annular passage 54. Part of the liquid leaves then from the device 16 via the evacuation passage 58, while the other part is recycled into the chamber 42 through the holes 64.
  • the liquid which flows in the injector 36, then in the venturi tube 44 has a very strong radial gradient of speed, that is to say that the speed of flow of the liquid along the vertical axis of the device is much more important in the immediate vicinity of this axis than along the walls of the injector and the venturi tube.
  • the liquid and the agglomerated solid particles which it carries are therefore subjected inside the injector 36 and the venturi tube 44 to very high shear forces, which break up the agglomerates.
  • a particle subjected to these shear forces divides into smaller particles, until the particle size is small enough for the shear induced by the radial velocity gradient in the injector 36 and in the venturi tube 44 is no longer enough to break these particles.
  • the passage through the device 16 according to the invention of a suspension containing particles with an average diameter close to 30 ⁇ m has the effect of reducing this average diameter to a value between 10 and 15 ⁇ m after a single pass and at a value close to 5 ⁇ m after recycling.
  • the particles in suspension with a diameter greater than 100 ⁇ m were identified.
  • the liquid initially entering the device 16 comprising 4% of particles of this type, it only contained 3% at the outlet of the venturi tube 44 after a first pass, this percentage being reduced to 1.5% after a recycling and 0.7% after two recycling.
  • the active parts of the device 16 that is to say mainly the injector 36 and the venturi tube 44, can be subjected to relatively rapid wear originating both from the presence of abrasive particles in the treated liquid and the corrosive nature of this liquid. Consequently, provision has been made in the device illustrated in FIG. 1 to be able to dismantle the assembly 30 from the upper zone 12 accessible to man, in order to allow the replacement of this part when this proves necessary.
  • zone 12 dismantles the screws 25 in order to remove the cover 24, which carries the assembly 30 via the ferrule 26.
  • this assembly can be replaced entirely. or only partially. Indeed, we have seen that the assembly 30 is fixed to the shell 26 in a removable manner by the screws 28 and that the part 31 of the housing in which the injector 36 is formed is itself fixed in a removable manner on the part 32 comprising the venturi tube 44 by the screws 34.
  • the device 116 illustrated in FIG. 2 comprises a cylindrical tank 118, of vertical axis, suspended from a horizontal slab 110, and an ejector assembly 130 received interchangeably in the tank 118, the replacement of this ejector assembly which can be carried out from the zone 112 situated above the slab 110.
  • the body of the ejector assembly 130 comprises three parts 131, 132 and 133 arranged coaxially around the vertical axis of the tank 118.
  • the external part 133 comprises, as in the embodiment of FIG. 1, a lower portion 149 in the form of a ring which rests on a portion 118a of greater thickness of the tank 118 by two seals 162.
  • This portion 149 is extended upwards by a tubular portion 150 closed at its upper end by a horizontal portion 151 fixed to the cover 124 accessible from the zone 112.
  • a crown 120 placed above the cover 124 maintains in position the assembly constituted by the cover 124 and the external part 133 using, for example, screws 121, in taken on the upper flange of the tank 118.
  • This part 133 internally supports by welded tie rods 153, the intermediate part 131 which has the shape of a hollow cylinder whose upper end carries in its center an injector 136.
  • the lower portion of the part 131 carries a seal 160 which cooperates with the part 118a of the tank 118 below the joints 162.
  • the part 131 itself supports internally, by tie rods 155, the central part 132 constituting a venturi tube 144 arranged, as well as the injector 136, coaxial with the vertical axis of the tank 118.
  • the upper end of inlet of the venturi tube 144 faces upwards and faces the outlet end of the injector 136.
  • the inlet passage 140 of the liquid which it is desired to treat which is formed in the thicker part 118a of the tank 118, opens out between the seals 160 and 162 preferably in a tangential direction, so as to create a vortex movement of the liquid in an external annular chamber 170 formed between the external 133 and intermediate 131 parts.
  • the outer annular passage 170 communicates with the upper inlet end of the injector 136, which itself communicates with the venturi tube 144.
  • the lower end of the venturi tube 144 opens out in front of a deflector 172 formed in the lower portion of the intermediate portion 131.
  • the shape of this deflector 172 makes it possible to avoid an accumulation of particles at this location, by forcing the liquid to make a change of direction radially outwards, then upwards.
  • Passages 174 formed in this lower portion of the portion 131 open out at their upper end into the bottom of the deflector 172 and at their lower end into a discharge chamber 156 formed in the bottom of the tank 118, below the joint 160.
  • These passages 174 have a common lower part arranged along the axis of the tank 118 and located immediately above an evacuation passage 158 formed, along this axis, in the bottom of the tank 118.
  • An internal annular recycling passage 176 is also formed between the intermediate part 131 and the central part 132 forming the venturi tube 144. This passage 176 opens at its lower end above the deflector 172 and, at its upper end, between the injector 136 and the venturi tube 144.
  • the liquid to be treated injected under pressure by the inlet passage 140, rises first by the outer annular passage 170 inside the ejector assembly 130. It then passes, in a downward movement, successively the injector 136 and the venturi tube 144. At the lower end of the latter, part of the liquid is directly evacuated through passages 174 and 158, then that another part is recycled in the venturi tube by the annular recycling passage 176.
  • the devices which have just been described successively with reference to FIGS. 1 and 2 comprise in both cases a non-cavitating recirculation ejector assembly, which constitutes, according to tests, the most efficient ejector assembly for obtaining disaggregation desired particles.
  • these ejector assemblies can be transformed into cavitating recirculation ejector assemblies. In this case, an even increased efficiency of the device is obtained, but the risks of abrasion are greater. This solution can however be used when the liquids to be treated only require reduced operating times.
  • FIG 3 there is shown schematically an alternative embodiment of the device 216 according to the invention, comprising an ejector assembly 230 with baffles.
  • the ejector assembly 230 is placed interchangeably in a tank 218 and its arrangement is such that the liquid to be treated circulates there from bottom to top, successively in a injector 236 then into a venturi tube 244.
  • the outlet from this venturi tube 244 opens into a system of baffles 280 giving this part of the ejector assembly a reduced height and an increased diameter.
  • This baffle system 280 is formed by a passage 282 formed between two opposite coaxial profiles 284 and 286.
  • the liquid to be treated admitted into the ejector assembly 230 through the intake passage 240 formed in the tank 218 circulates successively in the injector 236, in the venturi tube 244, then in passage 282 of the baffle system 280.
  • the injector 236, in the venturi tube 244, then in passage 282 of the baffle system 280 For the effect of disintegration of the agglomerated particles, obtained by shearing in the injector and in the venturi tube, in the manner described above, there is therefore added an additional disintegration of the particles under the effect of their impact against the walls of the baffle system 280.
  • part of the liquid having passed through the venturi tube 244 leaves the device through the evacuation passage 258, while another part of the liquid is recycled into the venturi tube 244 by passages 264 formed at the base of this one.
  • the device according to the invention which is particularly suitable for the treatment of fines obtained after the dissolution of the nuclear fuel sections in a nitric solution, can be used to treat any fluid containing suspensions of solid particles agglomerates that one wishes to disaggregate, and in particular industrial effluents.
  • the invention is not limited to the embodiments which have just been described by way of examples, but covers all the variants thereof.
  • the baffle system placed at the outlet of a venturi tube with upward circulation of liquid in the embodiment described with reference to FIG. 3 can also be placed at the outlet of a tube venturi with downward circulation of liquid.
  • the orientation and the location of the inlet and outlet passages for the liquid formed in the tank of the device can be modified without departing from the scope of the invention.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Disintegrating Or Milling (AREA)
  • Jet Pumps And Other Pumps (AREA)

Description

L'invention concerne un procédé permettant de désagréger des particules solides agglomérées qui se trouvent en suspension dans un liquide, ainsi qu'un dispositif mettant en oeuvre ce procédé.The invention relates to a method for disintegrating agglomerated solid particles which are in suspension in a liquid, as well as to a device implementing this method.

Le procédé et le dispositif selon l'invention s'appliquent avantageusement à la désagrégation des fines, c'est-à-dire des matières solides de granulométries faibles qui sont obtenues, lors du retraitement des combustibles nucléaires irradiés, après dissolution des combustibles coupés dans des solutions nitriques chaudes, puis clarification des solutions nitriques. Ces fines, dont la composition chimique est à base de zirconium, molybdène, ruthénium et autres métaux entrant dans la structure des combustibles, se présentent après clarification, par exemple dans une décanteuse pendulaire centrifuge, sous la forme de boues ou de solutions plus ou moins épaisses et plus ou moins agglomérées. Les fines, qui sont fortement irradiantes, sont transférées par des tuyauteries appropriées jusqu'à un site de vitrification où elles sont incluses dans une matrice de verre, après avoir séjourné dans des cuves de stockage dans lesquelles elles sont constamment agitées, par exemple au moyen de pulseurs, pour des raisons de sûreté nucléaire.The method and the device according to the invention advantageously apply to the disaggregation of fines, that is to say solid materials of small particle size which are obtained, during the reprocessing of irradiated nuclear fuels, after dissolving the fuels cut in hot nitric solutions, then clarification of the nitric solutions. These fines, whose chemical composition is based on zirconium, molybdenum, ruthenium and other metals entering the fuel structure, are present after clarification, for example in a pendulum centrifugal decanter, in the form of sludge or more or less solutions thick and more or less agglomerated. The fines, which are highly irradiating, are transferred by appropriate pipes to a vitrification site where they are included in a glass matrix, after having stayed in storage tanks in which they are constantly agitated, for example by means pulsers, for nuclear safety reasons.

Lors du transfert des boues dans les cuves de stockage et lors de leur stockage dans ces cuves, la présence d'agglomérats de dimensions variables et incontrôlées pose des problèmes délicats.During the transfer of sludge into storage tanks and during their storage in these tanks, the presence of agglomerates of variable and uncontrolled dimensions poses delicate problems.

Ainsi, les agglomérats constituent des particules abrasives qui créent une usure notamment dans les parties courbes des tuyauteries de transfert.Thus, the agglomerates constitute abrasive particles which create wear in particular in the curved parts of the transfer pipes.

De plus, ces agglomérats ont tendance à se déposer dans les zones non turbulentes des tuyauteries de transfert ou dans les parties de ces tuyauteries présentant des aspérités de surface, de telle sorte que des bouchons tendent à se former et se trouvent bloqués dans les parties coudées des tuyauteries. Ce risque de bouchage constitue un inconvénient d'autant plus difficile à résoudre que le caractère fortement irradiant des boues transportées rend toute intervention extrêmement difficile. Par ailleurs, il n'est pratiquement pas possible de résoudre ce problème en modifiant les installations et les paramètres d'écoulement des boues, en raison des difficultés de modélisation du comportement de ces dernières.In addition, these agglomerates tend to be deposit in the non-turbulent areas of the transfer pipes or in the parts of these pipes with surface roughness, so that plugs tend to form and are blocked in the bent parts of the pipes. This risk of blockage constitutes a drawback all the more difficult to resolve since the highly radiating nature of the sludge transported makes any intervention extremely difficult. Furthermore, it is practically not possible to solve this problem by modifying the installations and the flow parameters of the sludge, because of the difficulties in modeling the behavior of the latter.

Un autre inconvénient dû à la présence d'agglomérats de dimensions non contrôlées dans les boues transférées dans les cuves de stockage a pour origine le dépôt de ces agglomérats dans le fond des cuves, qui conduit à perturber le fonctionnement des pulseurs associés à ces dernières. Les interventions dans les cuves de stockage étant particulièrement délicates, il apparaît fortement souhaitable de désagréger les agglomérats qui se trouvent en solution dans les boues transportées jusqu'aux cuves, avant d'effectuer leur transport.Another drawback due to the presence of agglomerates of uncontrolled dimensions in the sludge transferred into the storage tanks is caused by the deposition of these agglomerates in the bottom of the tanks, which leads to disturbing the operation of the blowers associated with the latter. The interventions in the storage tanks being particularly delicate, it appears highly desirable to disaggregate the agglomerates which are in solution in the sludge transported to the tanks, before carrying out their transport.

Il est à noter que, si l'invention est particulièrement adaptée à la désagrégation des agglomérats contenus dans les fines fortement irradiantes obtenues lors du retraitement des combustibles nucléaires irradiés, elle n'est pas limitée à cette application et peut être utilisée à chaque fois qu'il apparaît souhaitable de désagréger des particules solides agglomérées, en suspension dans un liquide, notamment pour effectuer le traitement de certains effluents industriels, par exemple dans les industries chimique et agro-alimentaire.It should be noted that, if the invention is particularly suitable for the disaggregation of the agglomerates contained in the highly irradiating fines obtained during the reprocessing of irradiated nuclear fuels, it is not limited to this application and can be used whenever 'It seems desirable to disaggregate agglomerated solid particles, suspended in a liquid, in particular to carry out the treatment of certain industrial effluents, for example in the chemical and food industries.

Les documents GB-A-1 329 941 et GB-A-591 921 proposent de réduire la taille de particules solides en les mélangeant à un gaz porteur que l'on fait circuler dans un tube de venturi.Documents GB-A-1 329 941 and GB-A-591 921 propose to reduce the size of solid particles by mixing them with a carrier gas which is circulated in a venturi tube.

L'invention a précisément pour objet un procédé et un dispositif permettant de désagréger des particules solides agglomérées, qui se trouvent en suspension dans un liquide, afin par exemple de supprimer tout risque de formation de bouchons lors du transfert de ces particules ou tout risque de blocage d'un mécanisme quelconque par des particules agglomérées, ainsi que pour réduire si nécessaire le caractère abrasif de ces particules.The invention specifically relates to a method and a device for disaggregating agglomerated solid particles, which are suspended in a liquid, in order for example to eliminate any risk of formation of plugs during the transfer of these particles or any risk of blocking of any mechanism by agglomerated particles, as well as to reduce if necessary the abrasive nature of these particles.

Dans la définition la plus large de l'invention, il est proposé à cet effet de faire circuler, sous pression, le liquide contenant les particules solides agglomérées dans un tube de venturi formant un éjecteur qui assure une recirculation du liquide, de façon à désagréger plusieurs fois les particules.In the broadest definition of the invention, it is proposed for this purpose to circulate, under pressure, the liquid containing the agglomerated solid particles in a venturi tube forming an ejector which ensures a recirculation of the liquid, so as to disaggregate many times the particles.

En faisant passer plusieurs fois les particules solides agglomérées dans une tuyère du type tube de venturi, on soumet ces particules à un fort gradient de vitesse selon une direction radiale. En d'autres termes, dans une section perpendiculaire à l'axe de la tuyère, la vitesse de déplacement du fluide varie de façon très importante du centre à la périphérie. A chaque passage, les particules solides agglomérées sont donc soumises à un effort de cisaillement très élevé parallèlement à l'axe de la tuyère, ce qui a pour effet de désagréger les agglomérats véhiculés par le liquide.By passing the agglomerated solid particles several times through a nozzle of the venturi tube type, these particles are subjected to a strong speed gradient in a radial direction. In other words, in a section perpendicular to the axis of the nozzle, the speed of movement of the fluid varies very significantly from the center to the periphery. At each passage, the agglomerated solid particles are therefore subjected to a very high shear force parallel to the axis of the nozzle, which has the effect of disaggregating the agglomerates conveyed by the liquid.

Dans deux modes de réalisation particuliers de l'invention, on fait circuler le liquide respectivement de bas en haut et de haut en bas dans un tube de venturi sensiblement vertical. Des essais ont montré que l'efficacité du procédé est plus grande lorsque le liquide circule vers le bas à l'intérieur de la tuyère.In two particular embodiments of the invention, the liquid is circulated respectively from bottom to top and from top to bottom in a substantially vertical venturi tube. Tests have shown that the efficiency of the process is greater when the liquid circulates downwards inside the nozzle.

Une amélioration de l'efficacité du procédé est également obtenue en faisant circuler le liquide dans un système de chicanes, dans lequel l'effet dû au gradient de vitesse est associé à un effet de choc des agglomérats dans le système de chicanes placé à la sortie du tube de venturi.Improved process efficiency is also obtained by circulating the liquid in a baffle system, in which the effect due to the speed gradient is associated with a shock effect of the agglomerates in the baffle system placed at the outlet of the venturi tube.

L'invention a aussi pour objet un dispositif pour désagréger des particules solides agglomérées, en suspension dans un liquide, caractérisé par le fait qu'il comprend une cuve dans laquelle débouchent un passage d'admission et un passage d'évacuation du liquide contenant les particules solides agglomérées, un injecteur et un tube de venturi étant montés dans cet ordre dans la cuve, entre le passage d'admission et le passage d'évacuation, ainsi que des moyens de recyclage recyclant à l'entrée du tube de venturi une partie du liquide quittant ce tube.The invention also relates to a device for disaggregating agglomerated solid particles, suspended in a liquid, characterized in that it comprises a tank into which an inlet passage and an evacuation passage for the liquid containing the agglomerated solid particles, an injector and a venturi tube being mounted in this order in the tank, between the intake passage and the evacuation passage, as well as recycling means recycling part of the venturi tube liquid leaving this tube.

Dans un premier mode de réalisation de l'invention, le tube de venturi et l'injecteur sont disposés selon un axe commun sensiblement vertical, l'injecteur étant placé en dessous du tube de venturi et communiquant avec le passage d'admission par une chambre d'admission formée dans une partie inférieure de la cuve, le tube de venturi ayant une extrémité supérieure de sortie qui communique avec le passage d'évacuation par un passage annulaire formé autour du tube de venturi, et une extrémité inférieure d'entrée qui communique avec le passage annulaire par des trous formés dans une cloison de séparation et constituant lesdits moyens de recyclage.In a first embodiment of the invention, the venturi tube and the injector are arranged along a substantially vertical common axis, the injector being placed below the venturi tube and communicating with the intake passage through a chamber inlet formed in a lower part of the tank, the venturi tube having an upper outlet end which communicates with the discharge passage through an annular passage formed around the venturi tube, and a lower inlet end which communicates with the annular passage through holes formed in a partition and constituting said recycling means.

Selon un deuxième mode de réalisation de l'invention, le tube de venturi et l'injecteur sont disposés selon un axe commun sensiblement vertical, l'injecteur étant placé au-dessus du tube de venturi et communiquant avec le passage d'admission par un passage annulaire extérieur formé autour du tube de venturi, ce dernier comprenant une extrémité inférieure de sortie qui débouche au-dessus d'un déflecteur et communique avec le passage d'évacuation par une chambre d'évacuation formée dans une partie inférieure de la cuve, et une extrémité supérieure d'entrée qui communique avec l'extrémité inférieure de sortie par les moyens de recyclage, ces derniers moyens comprenant un passage annulaire intérieur de recyclage et un déflecteur placé en face de l'extrémité inférieure de sortie du tube de venturi.According to a second embodiment of the invention, the venturi tube and the injector are arranged along a substantially vertical common axis, the injector being placed above the venturi tube and communicating with the intake passage by a outer annular passage formed around the venturi tube, the latter comprising a lower outlet end which opens out above a deflector and communicates with the discharge passage through a discharge chamber formed in a lower part of the tank, and an upper inlet end which communicates with the lower outlet end by the recycling means, the latter means comprising an inner annular passage and a deflector placed opposite the lower outlet end of the venturi tube.

Dans tous les cas, un système de chicanes peut être placé en aval du tube de venturi.In all cases, a baffle system can be placed downstream of the venturi tube.

Différents modes de réalisation de l'invention vont à présent être décrits, à titre d'exemples non limitatifs, en se référant aux dessins annexés, dans lesquels :

  • la figure 1 est une vue en coupe verticale représentant schématiquement un dispositif conforme à l'invention permettant de désagréger des particules solides agglomérées, en suspension dans un liquide, dans lequel le liquide circule de bas en haut à l'intérieur du tube de venturi ;
  • la figure 2 est une vue en coupe verticale comparable à la figure 1 représentant un deuxième mode de réalisation du dispositif selon l'invention, dans lequel le liquide circule de haut en bas dans le tube de venturi ; et
  • la figure 3 est une vue en coupe schématique comparable aux figures 1 et 2 représentant un troisième mode de réalisation du dispositif selon l'invention, dans lequel ce dispositif comprend un système de chicanes.
Different embodiments of the invention will now be described, by way of nonlimiting examples, with reference to the appended drawings, in which:
  • Figure 1 is a vertical sectional view schematically showing a device according to the invention for disaggregating agglomerated solid particles, suspended in a liquid, in which the liquid circulates from bottom to top inside the venturi tube;
  • Figure 2 is a vertical sectional view comparable to Figure 1 showing a second embodiment of the device according to the invention, wherein the liquid flows from top to bottom in the venturi tube; and
  • Figure 3 is a schematic sectional view comparable to Figures 1 and 2 showing a third embodiment of the device according to the invention, wherein this device comprises a baffle system.

Sur la figure 1, la référence 10 désigne une dalle de béton horizontale qui sépare une zone supérieure 12, accessible à l'homme, d'une cellule inférieure 14 dans laquelle sont traités les liquides dangereux contenant les particules solides agglomérées que l'on désire désagréger.In FIG. 1, the reference 10 designates a horizontal concrete slab which separates an upper zone 12, accessible to man, from a lower cell 14 in which the dangerous liquids containing the agglomerated solid particles which are desired are treated. disaggregate.

Un dispositif 16 conforme à l'invention est suspendu à la dalle 10 de façon à être placé dans la cellule 14. Ce dispositif 16 comporte une cuve cylindrique 18, d'axe vertical, munie à son extrémité supérieure d'une bride 20 qui repose sur la dalle 10 et en est solidarisée de façon étanche, par exemple par des vis 22.A device 16 according to the invention is suspended from the slab 10 so as to be placed in the cell 14. This device 16 comprises a cylindrical tank 18, of vertical axis, provided at its upper end with a flange 20 which rests on the slab 10 and is securely joined thereto, for example by screws 22.

La cuve 18 est fermée à son extrémité supérieure par un couvercle 24 fixé de façon étanche sur la bride 20, par exemple par des vis 25. Une virole 26 fait saillie vers le bas, à partir de la face inférieure du couvercle 24, coaxialement à la cuve 18 et à l'intérieur de celle-ci. Cette virole 26 supporte à son extrémité inférieure, par l'intermédiaire de vis 28, un ensemble éjecteur désigné de façon générale par la référence 30.The tank 18 is closed at its upper end by a cover 24 tightly fixed on the flange 20, for example by screws 25. A ferrule 26 projects downwards, from the underside of the cover 24, coaxially with the tank 18 and inside of it. This ferrule 26 supports at its lower end, by means of screws 28, an ejector assembly generally designated by the reference 30.

Cet ensemble éjecteur 30 comporte un corps en trois parties 31, 32, 33, centré sur l'axe vertical de la cuve 18. Ces trois parties comprennent une partie inférieure 31, une partie centrale interne 32 et une partie supérieure externe 33.This ejector assembly 30 comprises a body in three parts 31, 32, 33, centered on the vertical axis of the tank 18. These three parts include a lower part 31, an internal central part 32 and an external upper part 33.

La partie inférieure 31, en forme de disque, est fixée par des vis 34 à l'extrémité inférieure de la partie centrale interne 32. Elle comporte en son centre, selon l'axe vertical de la cuve 18, un injecteur convergent 36. L'extrémité inférieure de plus grand diamètre de l'injecteur 36 débouche dans une chambre d'admission 38 formée dans la partie inférieure de la cuve 18. Un passage d'admission 40, formé dans une partie 18a de plus forte épaisseur de la paroi de la cuve 18, débouche également dans la chambre d'admission 38, afin de permettre l'introduction dans cette chambre du liquide contenant les particules solides agglomérées que l'on désire désagréger. Ce liquide est injecté sous pression dans le dispositif 16 par une pompe (non représentée), la pression d'injection étant par exemple au moins égal à 300 kPa.The lower part 31, in the form of a disc, is fixed by screws 34 to the lower end of the internal central part 32. It comprises in its center, along the vertical axis of the tank 18, a convergent injector 36. L the lower end of the larger diameter of the injector 36 opens into an inlet chamber 38 formed in the lower part of the tank 18. An inlet passage 40, formed in a thicker part 18a of the wall of the tank 18 also opens into the intake chamber 38, in order to allow the introduction into this chamber of the liquid containing the agglomerated solid particles which it is desired to disintegrate. This liquid is injected under pressure into the device 16 by a pump (not shown), the injection pressure being for example at least equal to 300 kPa.

La partie centrale interne 32 du corps de l'ensemble 30 comporte une portion inférieure 43 en forme de cloche, sous laquelle est fixée la partie inférieure 31, et une portion supérieure formant un tube de venturi 44. Une chambre de recyclage 42 est formée entre ladite portion inférieure 43 en forme de cloche et la partie inférieure 32a. L'extrémité inférieure du tube de venturi 44, disposé coaxialement à l'injecteur 36 et à la cuve 18, débouche dans la chambre de recyclage 42 au-dessus de l'injecteur 36. Le tube de venturi 44 forme intérieurement une zone inférieure d'entrée convergente 46 relativement courte et une zone supérieure de sortie divergente 48 relativement longue.The internal central part 32 of the body of the assembly 30 comprises a lower portion 43 in the shape of a bell, under which the lower part 31 is fixed, and an upper portion forming a venturi tube 44. A recycling chamber 42 is formed between said lower portion 43 in the shape of a bell and the lower part 32a. The lower end of the venturi tube 44, arranged coaxially with the injector 36 and the tank 18, opens into the recycling chamber 42 above the injector 36. The venturi tube 44 internally forms a lower zone d relatively short converging inlet 46 and a relatively long upper diverging outlet area 48.

Sur sa surface extérieure, la portion inférieure 43 en forme de cloche porte un joint d'étanchéité torique 60 qui coopère de façon étanche avec la surface intérieure de la partie 18a de plus forte épaisseur de la cuve 18, au-dessus de l'embouchure du passage d'admission 40. On isole ainsi la chambre d'admission 38 du reste de la cuve 18.On its outer surface, the bell-shaped lower portion 43 carries an O-ring seal 60 which cooperates sealingly with the inner surface of the thicker part 18a of the tank 18, above the mouth of the intake passage 40. The intake chamber 38 is thus isolated from the rest of the tank 18.

La partie supérieure externe 33 du corps de l'ensemble 30 comporte une portion inférieure 49 en forme de bague, fixée à l'extrémité inférieure de la virole 26 par les vis 28 et placée autour du tube de venturi 44. Cette portion inférieure 49 en forme de bague repose sur la partie 18a de plus forte épaisseur de la cuve 18, par l'intermédiaire de deux joints d'étanchéité toriques 62.The external upper part 33 of the body of the assembly 30 comprises a lower portion 49 in the form of a ring, fixed to the lower end of the ferrule 26 by the screws 28 and placed around the venturi tube 44. This lower portion 49 in ring shape rests on the thicker part 18a of the tank 18, by means of two O-ring seals 62.

La partie supérieure externe 32c comporte de plus, au-dessus de la portion inférieure 49 en forme de bague, une portion tubulaire 50 formée à son extrémité supérieure, au-dessus du tube de venturi 44, par une portion 51 en forme de calotte. La portion tubulaire 50 est disposée coaxialement autour du tube de venturi 44 et supporte ce dernier par l'intermédiaire de tirants soudés 53. Un passage annulaire 54 formé entre le tube de venturi 44 et la partie 32c fait communiquer l'extrémité supérieure du tube de venturi avec un passage d'évacuation 58 formé dans la partie 18a de plus forte épaisseur de la cuve 18 et débouchant dans la cuve entre les joints 60 et 62.The outer upper part 32c further comprises, above the lower portion 49 in the form of a ring, a tubular portion 50 formed at its upper end, above the venturi tube 44, by a portion 51 in the form of a cap. The tubular portion 50 is arranged coaxially around the venturi tube 44 and supports the latter by means of tie rods welded 53. An annular passage 54 formed between the venturi tube 44 and the part 32c makes the upper end of the venturi tube communicate with an evacuation passage 58 formed in the thicker part 18a of the tank 18 and opening in the tank between seals 60 and 62.

Des trous 64 formés dans la cloison supérieure horizontale de la partie inférieure 43 en forme de cloche font communiquer l'extrémité inférieure du passage annulaire 54 avec la chambre de recyclage 42. Ces trous permettent à une partie du fluide d'être recyclée à l'intérieur du tube venturi 44 comme on le verra par la suite.Holes 64 formed in the horizontal upper partition of the bell-shaped lower part 43 make the lower end of the annular passage 54 communicate with the recycling chamber 42. These holes allow part of the fluid to be recycled to the inside of the venturi tube 44 as will be seen later.

Le liquide contenant les particules solides agglomérées que l'on désire désagréger est introduit dans le dispositif par le passage d'admission 40, de préférence à une pression d'au moins 300 kPa. Le liquide sous pression admis dans la chambre d'admission 38 traverse l'ensemble 30 de bas en haut, en passant successivement par l'injecteur 36 et par les zones convergente 46 et divergente 48 du tube de venturi 44. L'écoulement du liquide dans l'injecteur 36, puis dans le tube de venturi 44 s'effectue à grande vitesse. Ainsi, pour un débit d'environ 5 m³ par heure de liquide introduit dans le dispositif 16 et un diamètre de sortie de l'injecteur 36 d'environ 10 mm, la vitesse atteinte par le liquide est d'environ 18 m par seconde.The liquid containing the agglomerated solid particles which it is desired to disintegrate is introduced into the device through the intake passage 40, preferably at a pressure of at least 300 kPa. The pressurized liquid admitted into the intake chamber 38 passes through the assembly 30 from bottom to top, passing successively through the injector 36 and through the converging 46 and diverging 48 zones of the venturi tube 44. The flow of the liquid in the injector 36, then in the venturi tube 44 takes place at high speed. Thus, for a flow rate of approximately 5 m³ per hour of liquid introduced into the device 16 and an outlet diameter of the injector 36 of approximately 10 mm, the speed reached by the liquid is approximately 18 m per second.

Au débit primaire du liquide parcourant de bas en haut l'injecteur 36, puis le tube de venturi 44 s'ajoute le débit induit résultant de l'entraînement par ce liquide primaire du liquide introduit dans la chambre de recyclage 42 au travers des trous 64. Des essais ont montré que le débit induit est très proche du débit primaire. Par conséquent, le débit de liquide traversant le tube de venturi 44 correspond à environ 10 m³ par heure dans l'exemple cité précédemment.In addition to the primary flow of liquid flowing from bottom to top the injector 36, then the venturi tube 44 is added the induced flow resulting from the entrainment by this primary liquid of the liquid introduced into the recycling chamber 42 through the holes 64 Tests have shown that the induced flow is very close to the primary flow. Therefore, the flow of liquid passing through the venturi tube 44 corresponds to approximately 10 m³ per hour in the example cited above.

Le liquide sortant à grande vitesse de l'extrémité supérieure du tube de venturi 44, dont le diamètre est par exemple d'environ 40 mm, heurte la portion 51 en forme de calotte et redescend par le passage annulaire 54. Une partie du liquide sort alors du dispositif 16 par le passage d'évacuation 58, alors que l'autre partie est recyclée dans la chambre 42 par les trous 64.The liquid exiting at high speed from the upper end of the venturi tube 44, the diameter of which is for example around 40 mm, strikes the portion 51 in the form of a cap and descends through the annular passage 54. Part of the liquid leaves then from the device 16 via the evacuation passage 58, while the other part is recycled into the chamber 42 through the holes 64.

Le liquide qui s'écoule dans l'injecteur 36, puis dans le tube de venturi 44 présente un très fort gradient radial de vitesse, c'est-à-dire que la vitesse d'écoulement du liquide selon l'axe vertical du dispositif est beaucoup plus important à proximité immédiate de cet axe que le long des parois de l'injecteur et du tube de venturi. Le liquide et les particules solides agglomérées qu'il véhicule sont donc soumis à l'intérieur de l'injecteur 36 et du tube de venturi 44 à des forces de cisaillement très élevées, qui désagrègent les agglomérats.The liquid which flows in the injector 36, then in the venturi tube 44 has a very strong radial gradient of speed, that is to say that the speed of flow of the liquid along the vertical axis of the device is much more important in the immediate vicinity of this axis than along the walls of the injector and the venturi tube. The liquid and the agglomerated solid particles which it carries are therefore subjected inside the injector 36 and the venturi tube 44 to very high shear forces, which break up the agglomerates.

Une particule soumise à ces forces de cisaillement se divise en particules plus petites, jusqu'à ce que la taille des particules soit suffisamment petite pour que le cisaillement induit par le gradient radial de vitesse dans l'injecteur 36 et dans le tube de venturi 44 ne soit plus suffisant pour casser ces particules.A particle subjected to these shear forces divides into smaller particles, until the particle size is small enough for the shear induced by the radial velocity gradient in the injector 36 and in the venturi tube 44 is no longer enough to break these particles.

Par exemple, on a constaté que le passage dans le dispositif 16 conforme à l'invention d'une suspension contenant des particules de diamètre moyen proche de 30 µm a pour effet de réduire ce diamètre moyen a une valeur comprise entre 10 et 15 µm après un seul passage et à une valeur proche de 5 µm après recyclage.For example, it has been found that the passage through the device 16 according to the invention of a suspension containing particles with an average diameter close to 30 μm has the effect of reducing this average diameter to a value between 10 and 15 μm after a single pass and at a value close to 5 µm after recycling.

Dans un autre essai, on a recensé les particules en suspension de diamètre supérieur à 100 µm. Le liquide entrant initialement dans le dispositif 16 comprenant 4 % de particules de ce type, il n'en contenait plus que 3 % à la sortie du tube de venturi 44 après un premier passage, ce pourcentage étant ramené à 1,5 % après un recyclage et à 0,7 % après deux recyclages.In another test, the particles in suspension with a diameter greater than 100 μm were identified. The liquid initially entering the device 16 comprising 4% of particles of this type, it only contained 3% at the outlet of the venturi tube 44 after a first pass, this percentage being reduced to 1.5% after a recycling and 0.7% after two recycling.

On comprend aisément que les parties actives du dispositif 16, c'est-à-dire principalement l'injecteur 36 et le tube de venturi 44, peuvent être soumises à une usure relativement rapide provenant à la fois de la présence de particules abrasives dans le liquide traité et du caractère corrosif de ce liquide. Par conséquent, il a été prévu dans le dispositif illustré sur la figure 1 de pouvoir démonter l'ensemble 30 depuis la zone supérieure 12 accessible à l'homme, afin de permettre le remplacement de cette pièce lorsque cela s'avère nécessaire.It is easily understood that the active parts of the device 16, that is to say mainly the injector 36 and the venturi tube 44, can be subjected to relatively rapid wear originating both from the presence of abrasive particles in the treated liquid and the corrosive nature of this liquid. Consequently, provision has been made in the device illustrated in FIG. 1 to be able to dismantle the assembly 30 from the upper zone 12 accessible to man, in order to allow the replacement of this part when this proves necessary.

Pour effectuer ce remplacement, l'opérateur présent dans la zone 12 démonte les vis 25 afin de retirer le couvercle 24, qui porte l'ensemble 30 par l'intermédiaire de la virole 26. Selon le cas, cet ensemble peut être remplacé en totalité ou seulement en partie. En effet, on a vu que l'ensemble 30 est fixé à la virole 26 de façon démontable par les vis 28 et que la partie 31 du boîtier dans laquelle est formé l'injecteur 36 est elle-même fixée de façon démontable sur la partie 32 comportant le tube de venturi 44 par les vis 34.To carry out this replacement, the operator present in zone 12 dismantles the screws 25 in order to remove the cover 24, which carries the assembly 30 via the ferrule 26. Depending on the case, this assembly can be replaced entirely. or only partially. Indeed, we have seen that the assembly 30 is fixed to the shell 26 in a removable manner by the screws 28 and that the part 31 of the housing in which the injector 36 is formed is itself fixed in a removable manner on the part 32 comprising the venturi tube 44 by the screws 34.

Dans le dispositif qui vient d'être décrit en se référant à la figure 1, le liquide à traiter s'écoule de bas en haut à l'intérieur de l'éjecteur formé par l'injecteur 36 et le tube de venturi 44. Dans la pratique, des essais ont montré qu'un meilleur rendement peut être obtenu en faisant circuler le liquide de haut en bas à l'intérieur de cet éjecteur. Un deuxième mode de réalisation du dispositif selon l'invention, dans lequel le liquide traverse l'éjecteur selon un mouvement descendant, va à présent être décrit brièvement en se référant à la figure 2.In the device which has just been described with reference to FIG. 1, the liquid to be treated flows from bottom to top inside the ejector formed by the injector 36 and the venturi tube 44. In in practice, tests have shown that better performance can be obtained by circulating the liquid from top to bottom inside this ejector. A second embodiment of the device according to the invention, in which the liquid passes through the ejector in a downward movement, will now be described briefly with reference to FIG. 2.

Sur la figure 2, les différentes parties du dispositif remplissant des fonctions identiques à des parties du dispositif qui vient d'être décrit en se référant à la figure 1 sont désignées par les mêmes chiffres de référence, augmentés de 100. De plus, seules les caractéristiques qui diffèrent de celles du dispositif décrit précédemment en se référant à la figure 1 sont décrites en détail.In FIG. 2, the different parts of the device fulfilling functions identical to parts of the device which has just been described with reference to FIG. 1 are designated by the same reference numbers, increased by 100. In addition, only the characteristics which differ from those of the device described above with reference to FIG. 1 are described in detail.

Comme dans le premier mode de réalisation décrit, le dispositif 116 illustré sur la figure 2 comprend une cuve cylindrique 118, d'axe vertical, suspendue à une dalle horizontale 110, et un ensemble éjecteur 130 reçu de façon interchangeable dans la cuve 118, le remplacement de cet ensemble éjecteur pouvant être effectué depuis la zone 112 située au-dessus de la dalle 110.As in the first embodiment described, the device 116 illustrated in FIG. 2 comprises a cylindrical tank 118, of vertical axis, suspended from a horizontal slab 110, and an ejector assembly 130 received interchangeably in the tank 118, the replacement of this ejector assembly which can be carried out from the zone 112 situated above the slab 110.

Le corps de l'ensemble éjecteur 130 comporte trois parties 131, 132 et 133 agencées coaxialement autour de l'axe vertical de la cuve 118. La partie extérieure 133 comporte, comme dans le mode de réalisation de la figure 1, une portion inférieure 149 en forme de bague qui repose sur une partie 118a de plus forte épaisseur de la cuve 118 par deux joints d'étanchéité 162. Cette portion 149 est prolongée vers le haut par une portion tubulaire 150 fermée à son extrémité supérieure par une portion horizontale 151 fixée au couvercle 124 accessible depuis la zone 112. Une couronne 120 placée au-dessus du couvercle 124 maintient en position l'ensemble constitué par le couvercle 124 et la partie extérieure 133 à l'aide, par exemple, de vis 121, en prise sur la bride supérieure de la cuve 118.The body of the ejector assembly 130 comprises three parts 131, 132 and 133 arranged coaxially around the vertical axis of the tank 118. The external part 133 comprises, as in the embodiment of FIG. 1, a lower portion 149 in the form of a ring which rests on a portion 118a of greater thickness of the tank 118 by two seals 162. This portion 149 is extended upwards by a tubular portion 150 closed at its upper end by a horizontal portion 151 fixed to the cover 124 accessible from the zone 112. A crown 120 placed above the cover 124 maintains in position the assembly constituted by the cover 124 and the external part 133 using, for example, screws 121, in taken on the upper flange of the tank 118.

Cette partie 133 supporte intérieurement par des tirants soudés 153, la partie intermédiaire 131 qui présente la forme d'un cylindre creux dont l'extrémité supérieure porte en son centre un injecteur 136. La portion inférieure de la partie 131 porte un joint d'étanchéité 160 qui coopère avec la partie 118a de la cuve 118 en dessous des joints 162.This part 133 internally supports by welded tie rods 153, the intermediate part 131 which has the shape of a hollow cylinder whose upper end carries in its center an injector 136. The lower portion of the part 131 carries a seal 160 which cooperates with the part 118a of the tank 118 below the joints 162.

La partie 131 supporte elle-même intérieurement, par des tirants 155, la partie centrale 132 constituant un tube de venturi 144 disposé, ainsi que l'injecteur 136, coaxialement à l'axe vertical de la cuve 118. L'extrémité supérieure d'entrée du tube de venturi 144 est tournée vers le haut et fait face à l'extrémité de sortie de l'injecteur 136.The part 131 itself supports internally, by tie rods 155, the central part 132 constituting a venturi tube 144 arranged, as well as the injector 136, coaxial with the vertical axis of the tank 118. The upper end of inlet of the venturi tube 144 faces upwards and faces the outlet end of the injector 136.

Le passage d'admission 140 du liquide que l'on désire traiter, qui est formé dans la partie 118a de plus forte épaisseur de la cuve 118, débouche entre les joints 160 et 162 de préférence selon une direction tangentielle, de façon à créer un mouvement tourbillonnaire du liquide dans une chambre annulaire extérieure 170 formée entre les parties extérieure 133 et intermédiaire 131.The inlet passage 140 of the liquid which it is desired to treat, which is formed in the thicker part 118a of the tank 118, opens out between the seals 160 and 162 preferably in a tangential direction, so as to create a vortex movement of the liquid in an external annular chamber 170 formed between the external 133 and intermediate 131 parts.

A son extrémité supérieure, le passage annulaire extérieur 170 communique avec l'extrémité supérieure d'entrée de l'injecteur 136, qui communique lui-même avec le tube de venturi 144.At its upper end, the outer annular passage 170 communicates with the upper inlet end of the injector 136, which itself communicates with the venturi tube 144.

L'extrémité inférieure du tube de venturi 144 débouche en face d'un déflecteur 172 formé dans la portion inférieure de la partie intermédiaire 131. La forme de ce déflecteur 172 permet d'éviter une accumulation de particules à cet endroit, en obligeant le liquide à effectuer un changement de direction radialement vers l'extérieur, puis vers le haut. Des passages 174 formés dans cette portion inférieure de la partie 131 débouchent à leur extrémité supérieure dans le fond du déflecteur 172 et à leur extrémité inférieure dans une chambre d'évacuation 156 formée dans le fond de la cuve 118, en dessous du joint 160. Ces passages 174 présentent une partie inférieure commune disposée selon l'axe de la cuve 118 et située immédiatement au-dessus d'un passage d'évacuation 158 formé, selon cet axe, dans le fond de la cuve 118.The lower end of the venturi tube 144 opens out in front of a deflector 172 formed in the lower portion of the intermediate portion 131. The shape of this deflector 172 makes it possible to avoid an accumulation of particles at this location, by forcing the liquid to make a change of direction radially outwards, then upwards. Passages 174 formed in this lower portion of the portion 131 open out at their upper end into the bottom of the deflector 172 and at their lower end into a discharge chamber 156 formed in the bottom of the tank 118, below the joint 160. These passages 174 have a common lower part arranged along the axis of the tank 118 and located immediately above an evacuation passage 158 formed, along this axis, in the bottom of the tank 118.

Un passage annulaire intérieur de recyclage 176 est également formé entre la partie intermédiaire 131 et la partie centrale 132 formant le tube de venturi 144. Ce passage 176 débouche à son extrémité inférieure au-dessus du déflecteur 172 et, à son extrémité supérieure, entre l'injecteur 136 et le tube de venturi 144.An internal annular recycling passage 176 is also formed between the intermediate part 131 and the central part 132 forming the venturi tube 144. This passage 176 opens at its lower end above the deflector 172 and, at its upper end, between the injector 136 and the venturi tube 144.

Dans le dispositif 116 qui vient d'être décrit en se référant à la figure 2, le liquide à traiter, injecté sous pression par le passage d'admission 140, monte d'abord par le passage annulaire extérieur 170 à l'intérieur de l'ensemble éjecteur 130. Il traverse ensuite, selon un mouvement descendant, successivement l'injecteur 136 et le tube de venturi 144. A l'extrémité inférieure de ce dernier, une partie du liquide est directement évacuée par les passages 174 et 158, alors qu'une autre partie est recyclée dans le tube de venturi par le passage annulaire de recyclage 176.In the device 116 which has just been described with reference to FIG. 2, the liquid to be treated, injected under pressure by the inlet passage 140, rises first by the outer annular passage 170 inside the ejector assembly 130. It then passes, in a downward movement, successively the injector 136 and the venturi tube 144. At the lower end of the latter, part of the liquid is directly evacuated through passages 174 and 158, then that another part is recycled in the venturi tube by the annular recycling passage 176.

Les dispositifs qui viennent d'être décrits successivement en se référant aux figures 1 et 2 comprennent dans les deux cas un ensemble éjecteur à recirculation non cavitant, qui constitue, d'après les essais, l'ensemble éjecteur le plus performant pour obtenir la désagrégation souhaitée des particules.The devices which have just been described successively with reference to FIGS. 1 and 2 comprise in both cases a non-cavitating recirculation ejector assembly, which constitutes, according to tests, the most efficient ejector assembly for obtaining disaggregation desired particles.

En modifiant les paramètres du procédé, on peut transformer ces ensembles éjecteurs en ensembles éjecteurs à recirculation cavitant. Dans ce cas, on obtient une efficacité encore accrue du dispositif, mais les risques d'abrasion sont plus importants. Cette solution peut cependant être utilisée lorsque les liquides à traiter ne nécessitent que des temps de fonctionnement réduits.By modifying the process parameters, these ejector assemblies can be transformed into cavitating recirculation ejector assemblies. In this case, an even increased efficiency of the device is obtained, but the risks of abrasion are greater. This solution can however be used when the liquids to be treated only require reduced operating times.

En variante, on peut également utiliser des dispositifs comprenant des tubes de venturi sans recirculation, lorsque les particules solides véhiculées par le liquide sont faiblement agglomérées. Lorsqu'une désagrégation maximum de ces particules doit impérativement être obtenue, comme c'est notamment le cas dans les applications nucléaires, l'utilisation d'ensembles éjecteurs à recirculation reste préférable.As a variant, it is also possible to use devices comprising venturi tubes without recirculation, when the solid particles conveyed by the liquid are weakly agglomerated. When a maximum disaggregation of these particles must imperatively be obtained, as is notably the case in nuclear applications, the use of recirculation ejector assemblies remains preferable.

Sur la figure 3, on a représenté de façon schématique une variante de réalisation du dispositif 216 selon l'invention, comportant un ensemble éjecteur 230 à chicanes.In Figure 3, there is shown schematically an alternative embodiment of the device 216 according to the invention, comprising an ejector assembly 230 with baffles.

Comme dans le mode de réalisation décrit précédemment en se référant à la figure 1, l'ensemble éjecteur 230 est placé de façon interchangeable dans une cuve 218 et son agencement est tel que le liquide à traiter y circule de bas en haut, successivement dans un injecteur 236 puis dans un tube de venturi 244. Cependant, la sortie de ce tube de venturi 244 débouche dans un système de chicanes 280 donnant à cette partie de l'ensemble éjecteur une hauteur réduite et un diamètre accru.As in the embodiment described above with reference to FIG. 1, the ejector assembly 230 is placed interchangeably in a tank 218 and its arrangement is such that the liquid to be treated circulates there from bottom to top, successively in a injector 236 then into a venturi tube 244. However, the outlet from this venturi tube 244 opens into a system of baffles 280 giving this part of the ejector assembly a reduced height and an increased diameter.

Ce système de chicanes 280 est formé par un passage 282 ménagé entre deux profils coaxiaux en vis-à-vis 284 et 286.This baffle system 280 is formed by a passage 282 formed between two opposite coaxial profiles 284 and 286.

Dans le dispositif 216 illustré sur la figure 3, le liquide à traiter admis dans l'ensemble éjecteur 230 par le passage d'admission 240 formé dans la cuve 218 circule successivement dans l'injecteur 236, dans le tube de venturi 244, puis dans le passage 282 du système de chicanes 280. A l'effet de désagrégation des particules agglomérées, obtenu par cisaillement dans l'injecteur et dans le tube de venturi, de la manière décrite précédemment, s'ajoute donc une désagrégation supplémentaire des particules sous l'effet des chocs de celles-ci contre les parois du système de chicanes 280.In the device 216 illustrated in FIG. 3, the liquid to be treated admitted into the ejector assembly 230 through the intake passage 240 formed in the tank 218 circulates successively in the injector 236, in the venturi tube 244, then in passage 282 of the baffle system 280. For the effect of disintegration of the agglomerated particles, obtained by shearing in the injector and in the venturi tube, in the manner described above, there is therefore added an additional disintegration of the particles under the effect of their impact against the walls of the baffle system 280.

Comme précédemment, une partie du liquide ayant traversé le tube de venturi 244 sort du dispositif par le passage d'évacuation 258, alors qu'une autre partie du liquide est recyclée dans le tube de venturi 244 par des passages 264 formés à la base de celui-ci.As before, part of the liquid having passed through the venturi tube 244 leaves the device through the evacuation passage 258, while another part of the liquid is recycled into the venturi tube 244 by passages 264 formed at the base of this one.

Comme on l'a déjà mentionné, le dispositif selon l'invention, qui est particulièrement adapté au traitement des fines obtenues après la dissolution des tronçons de combustible nucléaire dans une solution nitrique, peut être utilisé pour traiter tout fluide contenant des suspensions de particules solides agglomérées que l'on désire désagréger, et notamment des effluents industriels.As already mentioned, the device according to the invention, which is particularly suitable for the treatment of fines obtained after the dissolution of the nuclear fuel sections in a nitric solution, can be used to treat any fluid containing suspensions of solid particles agglomerates that one wishes to disaggregate, and in particular industrial effluents.

Bien entendu, l'invention n'est pas limitée aux modes de réalisation qui viennent d'être décrits à titre d'exemples, mais en couvre toutes les variantes. Ainsi, on comprend aisément que le système de chicanes placé à la sortie d'un tube de venturi à circulation ascendante de liquide dans l'exemple de réalisation décrit en référence à la figure 3 peut aussi être placé à la sortie d'un tube de venturi à circulation descendante de liquide. Par ailleurs, l'orientation et l'emplacement des passages d'admission et d'évacuation du liquide formés dans la cuve du dispositif peuvent être modifiés sans sortir du cadre de l'invention.Of course, the invention is not limited to the embodiments which have just been described by way of examples, but covers all the variants thereof. Thus, it is easily understood that the baffle system placed at the outlet of a venturi tube with upward circulation of liquid in the embodiment described with reference to FIG. 3 can also be placed at the outlet of a tube venturi with downward circulation of liquid. Furthermore, the orientation and the location of the inlet and outlet passages for the liquid formed in the tank of the device can be modified without departing from the scope of the invention.

Claims (9)

  1. Process for breaking up agglomerated solid particles suspended in a liquid, characterized in that it consists of making the liquid containing the agglomerated particles flow under pressure in a venturi tube (44, 144, 244), forming an ejector ensuring a recirculation of the liquid.
  2. Process according to claim 1, characterized in that it consists of making said liquid flow from bottom to top in a substantially vertical venturi tube (42, 244).
  3. Process according to claim 1, characterized in that it consists of making said liquid flow from top to bottom in a substantially vertical venturi tube (144).
  4. Process according to one of the preceding claims, characterized in that it consists of making said liquid flow in a baffle system (280) at the outlet of the venturi tube (244).
  5. Apparatus for breaking up agglomerated solid particles suspended in a liquid, characterized in that it comprises a tank (18, 118, 218), into which issue an admission passage (40, 140, 240) and an evacuation passage (58, 158, 258) for the liquid containing the solid agglomerated particles, an injector (36, 136, 236) and a venturi tube (44, 144, 244) being fitted in this order in the tank, between the admission passage and the evacuation passage, with recycling means (42, 64; 176; 264) by which part of the liquid leaving the venturi tube is recycled to the inlet of said tube.
  6. Apparatus according to claim 5, characterized in that the venturi tube (44, 244) and the injector (36, 236) are arranged in accordance with a substantially vertical axis, the injector being placed beneath the venturi tube and communicate with the admission passage (40, 240) by an admission chamber (38) formed in a lower part of the tank, the venturi tube having an upper outlet end which communicates with the evacuation passage (58, 258) by an annular passage (54) formed around the venturi tube, and a lower intake end which communicates with the annular passage (54) by recycling means incorporating holes (64, 264) formed in a separating partition.
  7. Apparatus according to claim 5, characterized in that the venturi tube (144) and the injector (136) are arranged in accordance with a substantially vertical axis, the injector being placed above the venturi tube and communicating with the admission passage (140) by an external annular passage (170) formed around the venturi tube, the latter having a lower outlet end, which issues in front of a deflector (172) and communicates with the evacuation passage (158) by an evacuation chamber (156) formed in a lower part of the tank, and an upper intake end which communicates with its lower outlet end by recycling means, incorporating an internal, annular recycling passage (176) and a deflector (172) placed in front of the lower outlet end of the venturi tube.
  8. Apparatus according to any one of the claims 5 to 7, characterized in that a system of baffles (280) is placed downstream of the venturi tube (244).
  9. Apparatus according to any one of the claims 5 to 8, characterized in that the venturi tube (44, 144, 244), the injector and the recycling means are installed in an interchangeable assembly (30, 130, 230).
EP91402260A 1990-08-20 1991-08-19 Process for disaggregating agglomerated solid particles which are suspended in a liquid Expired - Lifetime EP0472458B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9010476 1990-08-20
FR9010476A FR2665845B1 (en) 1990-08-20 1990-08-20 PROCESS FOR DISAGGRATING AGGLOMERATED SOLID PARTICLES, SUSPENDED IN A LIQUID.

Publications (2)

Publication Number Publication Date
EP0472458A1 EP0472458A1 (en) 1992-02-26
EP0472458B1 true EP0472458B1 (en) 1994-12-28

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EP (1) EP0472458B1 (en)
JP (1) JP3138293B2 (en)
KR (1) KR920004036A (en)
CN (1) CN1060229A (en)
CA (1) CA2049090A1 (en)
DE (1) DE69106277T2 (en)
FR (1) FR2665845B1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AUPN829796A0 (en) * 1996-02-23 1996-03-21 Bengold Holdings Pty Ltd Improved grinding method and apparatus for performing same
DE10343748B4 (en) * 2003-08-29 2005-11-10 BIONIK GmbH - Innovative Technik für die Umwelt Process for comminuting particulate organic substances in suspensions of microorganisms
TWI376354B (en) * 2003-12-03 2012-11-11 Miike Tekkosho Kk An apparatus for smashing organic substance particles
CN113333191B (en) * 2021-05-31 2022-07-05 武汉大学 Rotating shearing cavitation nozzle
CN116445183B (en) * 2023-03-14 2024-07-16 中国石油化工股份有限公司 Reaction device and method for jet mixing and reinforcing waste alkali liquid oxidation

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB591921A (en) * 1944-04-08 1947-09-02 Inst Gas Technology Improvements in or relating to apparatus for and method of comminuting a permeable material
US3348778A (en) * 1966-03-04 1967-10-24 Mineral Ind Corp Of America Reducing particle size of clay and rheology control of clay-water systems
GB1329941A (en) * 1972-01-05 1973-09-12 Texaco Development Corp Fluid energy grinding method and system
FR2311588A1 (en) * 1975-05-23 1976-12-17 Inst Francais Du Petrole Venturi device for disintegrating agglomerated powders - for rapid, complete sepn. of e.g. polyfluorocarbon polymers
US4619406A (en) * 1976-12-22 1986-10-28 Can-Am Engineering Corporation Hydraulic system and method of improving the working properties thereof

Also Published As

Publication number Publication date
JPH04250859A (en) 1992-09-07
FR2665845A1 (en) 1992-02-21
FR2665845B1 (en) 1995-01-20
DE69106277T2 (en) 1995-07-06
CN1060229A (en) 1992-04-15
JP3138293B2 (en) 2001-02-26
KR920004036A (en) 1992-03-27
EP0472458A1 (en) 1992-02-26
CA2049090A1 (en) 1992-02-21
DE69106277D1 (en) 1995-02-09

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