EP0003704A1 - Method of and apparatus for continuously mixing powdery solids and liquids, especially plaster with water - Google Patents

Method of and apparatus for continuously mixing powdery solids and liquids, especially plaster with water Download PDF

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Publication number
EP0003704A1
EP0003704A1 EP79400077A EP79400077A EP0003704A1 EP 0003704 A1 EP0003704 A1 EP 0003704A1 EP 79400077 A EP79400077 A EP 79400077A EP 79400077 A EP79400077 A EP 79400077A EP 0003704 A1 EP0003704 A1 EP 0003704A1
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EP
European Patent Office
Prior art keywords
tank
solid
mixer
liquid
mixing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP79400077A
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German (de)
French (fr)
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EP0003704B1 (en
Inventor
Adrien Delcoigne
Jacques Lanneau
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Saint Gobain Industries SA
Compagnie de Saint Gobain SA
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Saint Gobain Industries SA
Compagnie de Saint Gobain SA
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Publication of EP0003704A1 publication Critical patent/EP0003704A1/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
    • B28C5/08—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions using driven mechanical means affecting the mixing
    • B28C5/10—Mixing in containers not actuated to effect the mixing
    • B28C5/12—Mixing in containers not actuated to effect the mixing with stirrers sweeping through the materials, e.g. with incorporated feeding or discharging means or with oscillating stirrers
    • B28C5/16—Mixing in containers not actuated to effect the mixing with stirrers sweeping through the materials, e.g. with incorporated feeding or discharging means or with oscillating stirrers the stirrers having motion about a vertical or steeply inclined axis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/50—Mixing liquids with solids
    • B01F23/51—Methods thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/50—Mixing liquids with solids
    • B01F23/56—Mixing liquids with solids by introducing solids in liquids, e.g. dispersing or dissolving
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/50—Mixing liquids with solids
    • B01F23/59—Mixing systems, i.e. flow charts or diagrams
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
    • B01F27/80—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20—Measuring; Control or regulation
    • B01F35/22—Control or regulation
    • B01F35/221—Control or regulation of operational parameters, e.g. level of material in the mixer, temperature or pressure
    • B01F35/2218—Weight of at least one component to be mixed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/80—Forming a predetermined ratio of the substances to be mixed
    • B01F35/83—Forming a predetermined ratio of the substances to be mixed by controlling the ratio of two or more flows, e.g. using flow sensing or flow controlling devices

Definitions

  • the present invention relates to the mixing of pulverulent solids and liquids and it finds an application in the preparation of hydraulic binders and in particular in the continuous preparation of a mixture of plaster and water.
  • mixers of the type of plowshares or paddle mixers formed of a cylindrical tank in which rotates a vertical shaft provided with one or more levels of radial arms terminated by blades and / or plowshares.
  • the blades or the coulters scrape the walls of the tank, turn the products over and thus carry out a stirring.
  • mixers do not ensure sufficient dispersion of the pulverulent solid in the liquid, hence the heterogeneity of the fluidity of the outgoing mixture.
  • turbine mixers are known which consist of a tank in which a disc, a propeller or a turbine rotates at very high speed.
  • turbine mixers achieve a high shear rate and intensive turbulence at all points in the system, so that the dispersion and homogenization of the products are satisfactory.
  • the present invention overcomes the drawbacks of each of the known embodiments; it makes it possible to continuously supply a mixture of pulverulent solids and liquids with regular fluidity.
  • this invention prevents any parasitic deposition inside the mixer and, consequently, when working with evolutionary products, eliminates any premature build-up inside said mixer, a fluid evolutionary product being a liquid in which takes place a certain reaction giving rise to a physical or chemical transformation, capable in particular of causing a solid phase to appear or of modifying the characteristics of the solid phase initially charging the liquid.
  • a fluid evolutionary product being a liquid in which takes place a certain reaction giving rise to a physical or chemical transformation, capable in particular of causing a solid phase to appear or of modifying the characteristics of the solid phase initially charging the liquid.
  • the liquid is introduced along the wall of the mixer so as to form there a continuous curtain of liquid which prevents parasitic deposits.
  • the mixed product is extracted through the bottom of the mixer so as to avoid any solid retention in the tank of said mixer.
  • the filling state of the mixing tank determines the average residence time of the products to be mixed in the mixing tank and said average residence time is at least 3 seconds and preferably between 15 and 30 seconds.
  • the invention also provides an application of the process for the continuous mixing of plaster and water.
  • FIG. 1 represents a mixer M of pulverulent products and of liquids, according to the invention. It consists of a vertical cylindrical tank 1 which narrows in its lower part 2 to converge towards a discharge orifice 2 '. A deflocculating turbine 3 is mounted inside the tank 1 on a vertical shaft 4 arranged along the axis of the tank and driven by a motor 5. An intermediate bottom 6 of the tank 1 is constituted by the upper surface of a core 7 forming an obstacle inside the converging lower part 2 of the tank 1. This obstacle is a solid of revolution whose shape converges downwards.
  • the core 7 is a cone arranged point downward inside the narrowed lower part 2, itself conical , of the tank, the intermediate bottom then being formed by the flat base of said cone. As shown in FIG. 3, the cone 7 is held inside the lower part 2 of the tank 1 by fixing lugs 7A.
  • the lower part 2 of the mixer opens into an ejection device 8 in the form of an inverted cyclone, that is to say for example constituted by a conical envelope 9 arranged point at the top, with a flat base 10 and a collection pipe. 11 coming out flush with the base 10, tangentially to the conical casing 9 in the direction of rotation of the turbine 3.
  • This collection pipe 11 extends vertically and is provided with a valve 12 for adjusting the flow rate which delivers the mixture by a pipe 13 to the installations for using the mixture.
  • This valve 12 will be a pneumatic valve with direct passage constituted by an elastic sleeve enclosed in a rigid housing, controlled by a fluid sent under pressure between the housing and the elastic sleeve.
  • the upper edge of the tank 1 is provided with a covered annular weir 14, supplied with liquid by a flexible pipe 15.
  • a bypass 16 connected to the flexible pipe 15 and equipped with an adjustment valve 17 takes part of the liquid and directs it on the shaft 4 of the turbine 3.
  • a mixer capable of supplying 30 to 65 kg of mixture per minute may have the following characteristics:
  • FIG. 2 shows a complete mixing installation.
  • the mixer M with its tank 1, its core 7 forming an obstacle inside the converging part 2 of the tank, its intermediate bottom 6 constituted by the upper surface of the core 7 , its annular flow orifice at the periphery of the intermediate bottom 6, its ejection device 8 in the form of an inverted cyclone, the collection pipe 11 extended vertically and provided with the valve 12 for adjusting the flow rate of the outgoing mixture, the liquid supply with the spillway 14 and the bypass 16, the turbine 3 driven by the motor 5.
  • This FIG. 2 gives an example of a device S for supplying powdery solid and a device L for supplying liquid to the mixer M.
  • the solid supply device S proposed here comprises a hopper 18 disposed above a conveyor belt 19 forming a balance, balanced on a knife shown diagrammatically at 20 when it is loaded with a determined weight of product. Such a device is called a constant weight apis-balance.
  • This balance carpet 19 is associated with a hatch 21 for adjusting the thickness of the layer of product delivered by the hopper 18.
  • a vibrating metal corridor 22 provided with a sieve is arranged below the end of the carpet. balance 19.
  • This corridor 22 is inclined with respect to the horizontal by an angle which depends on the pulverulent product and which, in the case of plaster, will be of the order of 45 degrees.
  • This corridor 22 is arranged so that its lowest end overhangs the tank 1 of the mixer M and the pulverulent solid which it delivers falls in the center of the tank 1 on the turbine 3.
  • the liquid supply device L of this FIG. 2 the liquid supply is made from a reservoir 23 at constant level; the liquid flow is adjusted by a valve 24, a flow indicator 25 allows precise control of said flow.
  • the mixing plant operates as described below. We will take plaster as an example of a powdery solid and water as an example of liquid.
  • a water mixture weight ratio, Eo is plaster Po chosen, Eo and Po being respectively the mass flow of water and the mass flow of plaster.
  • a ratio of 0.8 will be conventionally used.
  • the material flow rates are first regulated.
  • the water flow rate is adjusted by the valve 24 to the desired Eo value.
  • the plaster flow is then adjusted to the value Po: the plaster contained in the hopper 18 spreads on the constant weight balance carpet 19 adjusted in equilibrium on the knife 20 for a determined weight of product, then the flow Po is obtained by adjusting the running speed of the weighing belt 19.
  • a residence time To of the plaster mixed in the mixer tank is chosen.
  • the turbine 3 is set in rotation.
  • the mixer tank is closed by obstruction of the pipe 13 or by closure of the valve 12.
  • the device L for supplying liquid, adjusted to provide a flow rate Eo is open for the time chosen To .
  • Water is introduced on the one hand by the weir 14, on the other hand by the pipe 16.
  • the turbine 3 rotating at high speed creates agitation of the water.
  • the plaster supply device S adjusted for a flow rate Po, is put into operation for a time To.
  • the plaster supply is cut off.
  • the turbine 3 is allowed to mix the water and the plaster for a time of the order of To / 2 counted from the cut of the plaster supply. Then, after this mixing time To / 2, simultaneously, we open the water supply always set for a flow rate Eo, we open the supply always set for a flow rate Po, we let the mixture flow into the tank of the mixer by opening the pipe 13 or by opening the valve 12 for adjusting the discharge rate of the mixture and by adjusting said valve 12 so that the quantity of product in the mixer remains constant and equal to the quantity present in the tank during starting during the mixing phase. The steady state is thus quickly reached.
  • the water and plaster supply is continuous with respective flow rates Eo and Po, the mixing is permanent, a constant quantity of mixture remains in the mixer tank, the average residence time of the mixture in the mixer is constant and equal to To chosen at start-up, the flow of the mixture is also done continuously with a flow rate (Eo + Po).
  • the water introduced into the annular spillway 14 is distributed uniformly over its entire periphery and by overflow trickles along the inner wall of the tank 1.
  • the water withdrawn by the pipe 16, metered by the valve 17 performs a sprinkling of the 'shaft 4 of the turbine 3.
  • the plaster contained in the hopper 18 spreads on the constant weight balance carpet 19 in equilibrium on the knife 20.
  • the balance carpet being adjusted for a flow Po, any overfeeding or underfeeding momentary plaster causes an imbalance which results in a change in position of the hatch 21 for adjusting the thickness of the plaster layer, a change which tends to restore balance.
  • the plaster falls on the sieve covering the vibrating metal corridor 22, the clusters break and the finely divided plaster flows in said metal corridor.
  • the latter by its vibrations, spreads over time the excesses and defects in the plaster supply, due to the landslide process; then it concentrates the plaster in a vein and causes the said vein to drop onto the turbine 3 which rotates at high speed inside the tank 1 of the mixer.
  • the curtain of water formed on the wall of the tank 1 and the excess water created on the shaft of the turbine prevent any deposit of powdered plaster and any undesirable primer of solidification on the wall of the tank 1 and on the tree 4.
  • the turbine 3 rotating at high speed rotates the products contained in the tank.
  • the speed of the turbine is determined so that a stable vortex with a vertical axis is formed, that is to say a single hollow vortex lining the walls of the tank internally.
  • the surface of the mixture then takes a conical shape centered on the shaft 4 of the turbine 3.
  • the depth of the vortex depends on the geometry of the tank of the mixer M and on the speed of rotation of the turbine 3 which is adjusted so that the bottom of the vortex touches said turbine 3. This optimal speed depends on the fluidity of the mixture, which is a function of the ratio Eo and To. Po
  • the powdery plaster delivered by the vibrating metal corridor 22 falls in the center of the vortex on the turbine 3 rotating at high speed.
  • the rotation of the products ensures homogenization, and the inclination of the surface of the liquid avoids the stagnation of solid products in clusters.
  • the intermediate bottom 6 of the mixer M constituted by the upper surface of the core 7 conforming to the flow patterns of the turbine 3, that is to say the circulation lines of the mixing zone, and being for example flat and arranged There is no deposit in the immediate vicinity of the turbine.
  • the plaster / water mixture is extracted regularly in the annular space between the obstacle-core 7 and the converging wall of the lower part 2 of the mixer.
  • the position of this core 7 with respect to the converging wall of the lower part 2 of the mixer defines the dimensions of this annular space and thus determines a certain limit flow rate.
  • the mixture flows in this space with a sufficient speed which does not allow solidification.
  • the speed of the plaster mixture measured along the generatrix of the cone core 7 will be at least 30 cm / second and generally around 1 m / second.
  • the sections of the mixture extraction pipes located downstream will also be chosen for reaching this minimum speed, thus avoiding deposits and premature caking.
  • the mixture converges at the tip 2 'of the lower part 2 of the mixer.
  • the mixture still in rotational circulation enters the ejection device 8 in the form of an inverted cyclone.
  • the mixture remains pressed along the conical walls of the ejection device 8 and descends along these walls to the base 10 of the device. by describing a spiral. In this way, an uncontrolled vortex does not form, which can give rise to a dead zone where there is a risk of solidification.
  • the mixture in rotational circulation is then captured by the collection pipe 11 and it then gives a full cylindrical stream whose flow will now be able to be adjusted precisely by the throttling valve located at the end of said collection pipe 11 .
  • the passage section of this valve 22 is constantly adjusted to maintain a constant quantity of melan ge in the mixer tank and thereby a constant residence time of said mixture in said mixer. This residence time allows the homogenization of the mixture and the elimination of feed irregularities.
  • valve 12 can be obtained in various ways. It could be manual, but in the case of plaster, taking into account the rapid process of evolution of powdered plaster as soon as it is in contact with water, if one wants to have a mixture with constant fluidity, having so stayed a specific time in the mixer, it will be automatic.
  • the regulation signal sent to valve 12 will be provided by a photoelectric cell reacting as soon as the mixture in the mixer tank has reached a certain level, or by a capacitive system measuring the electrical capacity of a determined height of the mixture, or by a pressure probe placed at the bottom of the tank, or preferably by weighing the mixer.
  • the valve 12 will be a direct passage valve constituted by a rigid body, by an elastic inner sleeve and by a fluid supply between the rigid body and the sleeve, said fluid being capable of compressing the elastic sleeve to reduce the flow rate of the valve. .
  • a modulation of the pressure of the fluid controlling the opening of the valve 12 is produced, modulation which causes the sleeve to constantly deform.
  • the sleeve will be made of an elastic, flexible impermeable material, such as air chamber rubber and it will have at rest substantially the same dimensions as the interior of the rigid body which envelops it.
  • valve 12 will be controlled using a pneumatic leakage control system varying the opening of said valve 12 as a function of the weight of the mixer and we will take advantage of the system's oscillations induced by the vibrations due to the movement of the mixture and the turbine in the mixer tank to modulate the pressure of the control fluid. More specifically in this case the mixer will be separated from the upstream and downstream installations to make weighing possible.
  • a pneumatic leak system mainly comprises a pneumatic circuit and a force balance beam.
  • the pneumatic circuit is supplied with a constant flow of compressed air; it comprises two branches, one going to the valve 12, the other opening into the open air near one end of the balance beam and thus determining a certain leak, variable when the beam oscillates.
  • the Scourge of Balance weighs the mixer continuously. It is balanced for a specific weight of the mixer thanks to a return spring and an adjustable calibration counterweight and it oscillates when this weight varies. It then increases or decreases the leakage from the pneumatic circuit and by backlash, respectively decreases or increases the pressure of the air directed onto the valve, thus modifying the passage section of the valve and consequently the discharge rate of the mixer.
  • the movements of the mixture and the vibrations of the turbine cause the beam to oscillate slightly continuously; and it is these light oscillations, which, detected by the pneumatic circuit, generate the pressure modulation of the valve control fluid.
  • the elastic sleeve of the valve receiving in addition to its regulation signal a pulsating signal resulting from the vibrations induced by the turbine is constantly deformed, thus preventing any plaster deposit.
  • the ejection device can be constituted by any conventional means in fluid mechanics, capable of transforming any flow, in particular a rotational flow, into a solid vein.
  • an impact crown 26 formed by a pot pos- sedar a bottom and a lateral ejection tube.
  • this mean retention time To is determined by the filling state of the mixing tank and it is by maintaining this filling state that the average retention time is kept constant.
  • the average retention time will be at least equal to three seconds and preferably between 15 and 30 seconds so that sufficient homogenization of the solid and liquid products is obtained.
  • additives are introduced at any of the different stages of mixing, additive word designating reactive or inert products, solid or liquid, preferably finely divided when they are solid. It will thus be possible to introduce solid additives with the pulverulent plaster, either because the addition has been made beforehand by the plaster manufacturer, or by distributing said additive in the hopper 18 or on the weighing carpet 19. also introduce solid or liquid additives into the water, or even directly into the mixer. Said additives may consist of adjuvants chemical or reinforcing elements of plaster such as cut or finely divided fibers.

Abstract

1. Process for continuously mixing pulverulent solids and liquids, in particular primarily plaster and water, in which the solid phase and the liquid phase are continuously introduced into a mixing vat at the respective rates required to obtain the desired proportions of solid and liquid in the mixture, the products contained in the vat are swirled in the vat the aid of a turbine to effect mixing, the mixture is continuously discharged, the rates of feed and of discharge are regulated to maintain constantly a certain state of filling, characterized in that the liquid is essentially introduced as a continuous film along the vertical wall of the mixer, the products are swirled inside a single vortex, the solid is introduced at the center of the vortex thus produced, and the mixture is extracted from the periphery of the bottom of the mixing vat.

Description

La présente invention concerne le mélangeage de solides pulvérulents et de liquides et elle trouve une application dans la préparation des liants hydrauliques et en particulier dans la préparation en continu d'un mélange de plâtre et d'eau.The present invention relates to the mixing of pulverulent solids and liquids and it finds an application in the preparation of hydraulic binders and in particular in the continuous preparation of a mixture of plaster and water.

Il est connu, pour assurer le mélangeage de solides pulvérulents et de liquides, d'utiliser des mélangeurs du type mélangeurs à socs ou à pales, formés d'une cuve cylindrique dans laquelle tourne un arbre vertical muni de un ou plusieurs niveaux de bras radiaux terminés par des pales et/ou des socs. Les pales ou les socs raclent les parois de la cuve, retournent les produits et effectuent ainsi un brassage. Mais de tels mélangeurs n'assurent pas une dispersion suffisante du solide pulvérulent dans le liquide, d'où une hétérogénéité de la fluidité du mélange sortant. On connait d'autre part des mélangeurs à turbine constitués par une cuve dans laquelle tourne à très grande vitesse un disque, une hélice ou une turbine. Le solide et le liquide sont reçus sur la turbine qui les disperse instantanément. A l'opposé des mélangeurs à socs, les mélangeurs à turbine réalisent un taux de cisaillement élevé et une turbulence intensive en tous les points du système, de sorte que la dispersion et l'homogénéisation des produits sont satisfaisantes.It is known, to ensure the mixing of pulverulent solids and liquids, to use mixers of the type of plowshares or paddle mixers, formed of a cylindrical tank in which rotates a vertical shaft provided with one or more levels of radial arms terminated by blades and / or plowshares. The blades or the coulters scrape the walls of the tank, turn the products over and thus carry out a stirring. However, such mixers do not ensure sufficient dispersion of the pulverulent solid in the liquid, hence the heterogeneity of the fluidity of the outgoing mixture. On the other hand, turbine mixers are known which consist of a tank in which a disc, a propeller or a turbine rotates at very high speed. The solid and the liquid are received on the turbine which disperses them instantly. In contrast to coulter mixers, turbine mixers achieve a high shear rate and intensive turbulence at all points in the system, so that the dispersion and homogenization of the products are satisfactory.

Mais si l'on étudie le comportement d'un tel mélangeur, en y introduisant une matière colorée ou en général toute matière pouvant être aisément décelée qu'on appelle traceur,et en enregistrant la concentration dudit traceur à la sortie, on constate qu'une variation d'alimentation se répercute sans modification à la sortie au bout d'un temps très bref de l'ordre de la seconde. Ainsi, dans un mélangeur à turbine, le temps de séjour des produits est très bref, si bref que les irrégularités à l'alimentation ne peuvent être effacées par l'opération de mélangeage et se retrouvent intégralement en sortie. Lorsqu'on désirera une fluidité régulière du produit final, impossible à obtenir par une régularité d'alimentation, les mélangeurs à turbine ne conviendront donc pas.But if we study the behavior of such a mixer, by introducing a colored matter into it or in general any matter which can be easily detected, which is called a tracer, and by recording the concentration of said tracer at the outlet, we find that a variation in supply is reflected without modification at the outlet after a very long time short of the order of a second. Thus, in a turbine mixer, the residence time of the products is very short, so brief that the irregularities in the feed cannot be erased by the mixing operation and are found entirely at the outlet. When one wishes a regular fluidity of the final product, impossible to obtain by a regularity of supply, the turbine mixers will therefore not be suitable.

La présente invention remédie aux inconvénients de chacune des réalisations connues; elle permet de fournir en continu un mélange de solides pulvérulents et de liquides avec une fluidité régulière.The present invention overcomes the drawbacks of each of the known embodiments; it makes it possible to continuously supply a mixture of pulverulent solids and liquids with regular fluidity.

En outre, cette invention empêche tout dépôt parasite à l'intérieur du mélangeur et,en conséquence,lorsqu'on travaille avec des produits évolutifs,supprime toute prise en masse prématurée à l'intérieur dudit mélangeur, un produit évolutif fluide étant un liquide dans lequel se produit une certaine réaction donnant lieu à une transformation physique ou chimique,susceptible notamment de faire apparaître une phase solide ou de modifier les caractéristiques de la phase solide chargeant initialement le liquide. Comme exemple de produit évolutif, on peut citer le plâtre qui, dès qu'il est mélangé à l'eau, se met à évoluer rapidement jusqu'à ce qu'il soit totalement pris en masse.Furthermore, this invention prevents any parasitic deposition inside the mixer and, consequently, when working with evolutionary products, eliminates any premature build-up inside said mixer, a fluid evolutionary product being a liquid in which takes place a certain reaction giving rise to a physical or chemical transformation, capable in particular of causing a solid phase to appear or of modifying the characteristics of the solid phase initially charging the liquid. As an example of an evolving product, we can cite plaster which, as soon as it is mixed with water, begins to evolve rapidly until it is completely solidified.

Elle propose un procédé de mélangeage en continu de solides pulvérulents et de liquides, qui consiste:

  • - à introduire en continu la phase liquide dans une cuve de mélangeage;
  • - à introduire en continu la phase solide dans ladite cuve avec un débit tel que soient respectées les proportions désirées de solide et de liquide dans le mélange;
  • - à assurer la rotation des produits contenus dans la cuve de façon à former un vortex;
  • - à régler les débits d'alimentation en solide et en liquide pour que se maintienne constamment un certain état de remplissage de la cuve;
  • - à évacuer en continu le mélange des produits pour que se conserve cet état de remplissage.
It proposes a process for the continuous mixing of pulverulent solids and liquids, which consists of:
  • - continuously introducing the liquid phase into a mixing tank;
  • - Continuously introducing the solid phase into said tank at a rate such that the desired proportions of solid and liquid in the mixture are respected;
  • - ensuring the rotation of the products contained in the tank so as to form a vortex;
  • - to regulate the flow rates of solid and liquid so that a certain state of filling of the tank is constantly maintained;
  • - to continuously evacuate the mixture of products so that this filling state remains.

Avantageusement, le liquide est introduit le long de la paroi du mélangeur de façon à y former un rideau continu de liquide qui empêche les dépôts parasites.Advantageously, the liquid is introduced along the wall of the mixer so as to form there a continuous curtain of liquid which prevents parasitic deposits.

Préférentiellement, le produit mélangé est extrait au travers du fond du mélangeur de façon à éviter toute rétention de solide dans la cuve dudit mélangeur.Preferably, the mixed product is extracted through the bottom of the mixer so as to avoid any solid retention in the tank of said mixer.

Ce régime permanent s'obtient après une période de démarrage qui comporte les étapes suivantes:

  • - introduction dans une cuve de mélangeage du liquide et du solide dans les proportions du rapport pondéral de mélange préalablement choisi, jusqu'à atteindre un certain état de remplissage de ladite cuve de mélangeage;
  • - mise en rotation dans la cuve, des produits introduits et maintien en rotation pendant un temps déterminé,
This permanent regime is obtained after a start-up period which includes the following stages:
  • - introduction into a mixing tank of the liquid and the solid in the proportions of the weight ratio of mixing previously chosen, until reaching a certain filling state of said mixing tank;
  • - rotation of the introduced products in the tank and maintenance of rotation for a determined time,

Puis, simultanément:

  • - admission en continu dans la cuve,du liquide et du solide avec des débits tels que soit respecté le rapport mondéral de mélange;
  • - évacuation en continu du mélange avec un débit tel que se conserve l'état de remplissage.
Then, simultaneously:
  • - continuous admission into the tank, of liquid and solid with flow rates such that the world mixing ratio is respected;
  • - continuous evacuation of the mixture at a rate such that the filling state remains.

L'état de remplissage de la cuve de mélangeage détermine le temps de séjour moyen des produits à mélanger dans la cuve de mélangeage et ledit temps de séjour moyen est au moins égal à 3 secondes et préférentiellement compris entre 15 et 30 secondes.The filling state of the mixing tank determines the average residence time of the products to be mixed in the mixing tank and said average residence time is at least 3 seconds and preferably between 15 and 30 seconds.

L'invention propose également une application du procédé au mélangeage en continu de plâtre et de l'eau.The invention also provides an application of the process for the continuous mixing of plaster and water.

L'invention propose en outre un dispositif pour mettre en oeuvre le procédé de mélangeage. Un tel dispositif est constitué par un mélangeur caractérisé en ce qu'il comprend:

  • . une cuve formée par un solide de révolution creux muni à son extrémité inférieure d'un orifice d'écoulement équipé de moyens de réglage du débit d'écoulement, ladite cuve possédant une paroi intérieure ajourée qui constitue un fond intermédiaire;
  • . une turbine défloculeuse disposée à l'intérieur de la cuve au-dessus du fond intermédiaire et tournant autour d'un axe vertical situé suivant l'axe de la cuve;
  • . des moyens d'alimentation en liquide qui, avantageusement, distribuent le liquide en un rideau continu le long de la paroi de la cuve de mélangeage;
  • . des moyens d'alimentation en solide.
The invention further provides a device for implementing the mixing process. Such a device is constituted by a mixer characterized in that it comprises:
  • . a tank formed by a hollow solid of revolution provided at its lower end with a flow orifice equipped with means for adjusting the flow rate, said tank having an perforated inner wall which constitutes an intermediate bottom;
  • . a deflocculating turbine arranged inside the tank above the intermediate bottom and rotating around a vertical axis located along the axis of the tank;
  • . liquid supply means which, advantageously, distribute the liquid in a continuous curtain along the wall of the mixing tank;
  • . solid feed means.

L'invention sera maintenant décrite en référence aux dessins, qui représentent:

  • - figure 1: un schéma de la cuve de mélangeage;
  • - figure 2: une installation complète de mélangeage;
  • - figure 3: une section horizontale de la cuve de mélangeage de la figure 1, prise immédiatement au-dessus du fond intermédiaire;
  • - figure 4: une section horizontale du dispositif d'éjection prise immédiatement au-dessus du fond dudit dispositif;
  • - figure 5: un schéma d'une partie du mélangeur dont le dispositif d'éjection est une couronne d'impact.
The invention will now be described with reference to the drawings, which represent:
  • - Figure 1: a diagram of the mixing tank;
  • - Figure 2: a complete mixing installation;
  • - Figure 3: a horizontal section of the mixing tank of Figure 1, taken immediately above the intermediate bottom;
  • - Figure 4: a horizontal section of the ejection device taken immediately above the bottom of said device;
  • - Figure 5: a diagram of a part of the mixer whose ejection device is an impact ring.

La figure 1 représente un mélangeur M de produits pulvérulents et de liquides, conforme à l'invention. Il est constitué par une cuve 1 cylindrique verticale qui se rétrécit dans sa partie basse 2 pour converger vers un orifice d'évacuation 2'. Une turbine défloculeuse 3 est montée à l'intérieur de la cuve 1 sur un arbre vertical 4 disposé suivant l'axe de la cuve et entraîné par un moteur 5. Un fond intermédiaire 6 de la cuve 1 est constitué par la surface supérieure d'un noyau 7 formant obstacle à l'intérieur de la partie basse convergente 2 de la cuve 1. Cet obstacle est un solide de révolution dont la forme converge vers le bas. Il est centré sur l'axe de la cuve et il a des dimensions inférieures aux dimensions intérieures de la partie basse convergente 2 du mélangeur, ménageant ainsi un orifice annulaire à sa périphérie.La surface supérieure 6 du noyau 7 a une forme telle qu'elle épouse les figures d'écoulement correspondant à la turbine 3. Dans une forme de réalisation simple illustrée par la figure 1, le noyau 7 est un cône disposé pointe en bas à l'intérieur de la partie basse rétrécie 2, elle-même conique, de la cuve, le fond intermédiaire étant alors constitué par la base plane dudit cône. Comme montré figure 3, le cône 7 est maintenu à l'intérieur de la partie basse 2 de la cuve 1 par des pattes de fixation 7A.FIG. 1 represents a mixer M of pulverulent products and of liquids, according to the invention. It consists of a vertical cylindrical tank 1 which narrows in its lower part 2 to converge towards a discharge orifice 2 '. A deflocculating turbine 3 is mounted inside the tank 1 on a vertical shaft 4 arranged along the axis of the tank and driven by a motor 5. An intermediate bottom 6 of the tank 1 is constituted by the upper surface of a core 7 forming an obstacle inside the converging lower part 2 of the tank 1. This obstacle is a solid of revolution whose shape converges downwards. It is centered on the axis of the tank and has dimensions smaller than the internal dimensions of the converging lower part 2 of the mixer, thus providing an annular orifice at its periphery. The upper surface 6 of the core 7 has a shape such that it follows the flow figures corresponding to the turbine 3. In a simple embodiment illustrated by FIG. 1, the core 7 is a cone arranged point downward inside the narrowed lower part 2, itself conical , of the tank, the intermediate bottom then being formed by the flat base of said cone. As shown in FIG. 3, the cone 7 is held inside the lower part 2 of the tank 1 by fixing lugs 7A.

La partie basse 2 du mélangeur débouche dans un dispositif d'éjection 8 en forme de cyclone inversé, c'est-à-dire par exemple constitué par une enveloppe conique 9 disposée point en haut, avec une base 10 plane et un tuyau de captage 11 sortant au ras de la base 10, tangentiellement à l'enveloppe conique 9 dans le sens de rotation de la turbine 3. Ce tuyau de captage 11 se prolonge verticalement et est muni d'une vanne 12 de réglage du débit qui délivre le mélange par un tuyau 13 aux installations d'utilisation du mélange. Cette vanne 12 sera une vanne pneumatique à passage direct constituée par un manchon élastique enfermé dans un boîtier rigide, commandée par un fluide envoyé sous pression entre le boîtier et le manchon élastique.The lower part 2 of the mixer opens into an ejection device 8 in the form of an inverted cyclone, that is to say for example constituted by a conical envelope 9 arranged point at the top, with a flat base 10 and a collection pipe. 11 coming out flush with the base 10, tangentially to the conical casing 9 in the direction of rotation of the turbine 3. This collection pipe 11 extends vertically and is provided with a valve 12 for adjusting the flow rate which delivers the mixture by a pipe 13 to the installations for using the mixture. This valve 12 will be a pneumatic valve with direct passage constituted by an elastic sleeve enclosed in a rigid housing, controlled by a fluid sent under pressure between the housing and the elastic sleeve.

Le bord supérieur de la cuve 1 est muni d'un déversoir annulaire 14 recouvert, alimenté en liquide par un tuyau flexible 15. Une dérivation 16 branchée sur le tuyau flexible 15 et équipée d'une vanne de réglage 17 prélève une partie du liquide et la dirige sur l'arbre 4 de la turbine 3.The upper edge of the tank 1 is provided with a covered annular weir 14, supplied with liquid by a flexible pipe 15. A bypass 16 connected to the flexible pipe 15 and equipped with an adjustment valve 17 takes part of the liquid and directs it on the shaft 4 of the turbine 3.

A titre d'exemple, un mélangeur pouvant fournir de 30 à 65 kg de mélange par mn pourra avoir les caractéristiques suivantes:

Figure imgb0001
For example, a mixer capable of supplying 30 to 65 kg of mixture per minute may have the following characteristics:
Figure imgb0001

La figure 2 représente une installation complète de mélangeage.On retrouve le mélangeur M avec sa cuve 1, son noyau 7 formant obstacle à l'intérieur de la partie convergente 2 de la cuve, son fond intermédiaire 6 constitué par la surface supérieure du noyau 7, son orifice d'écoulement annulaire à la périphérie du fond intermédiaire 6, son dispositif d'éjection 8 en forme de cyclone inversé, le tuyau de captage 11 prolongé verticalement et muni de la vanne 12 de réglage du débit du mélange sortant, l'alimentation en liquide avec le déversoir 14 et la dérivation 16, la turbine 3 mue par le moteur 5. Cette figure 2 donne en exemple un dispositif S d'alimentation en solide pulvérulent et un dispositif L d'alimentation en liquide,du mélangeur M. Le dispositif S d'alimentation en solide proposé ici comporte une trémie 18 disposée au-dessus d'un tapis transporteur 19 formant balance, en équilibre sur un couteau schématisé en 20 lorsqu'il est chargé d'un poids déterminé de produit. Un tel appareil est dit apis-balance à poids constant. Ce tapis-balance 19 est associé à une trappe 21 de réglage de l'épaisseur de la couche de produit délivrée par la trémie 18. Un couloir métallique vibrant 22 muni d'un tamis est disposé au-dessous de l'extrémité du tapis-balance 19.Ce couloir 22 est incliné par rapport à l'horizontale d'un angle qui dépend du produit pulvérulent et qui, dans le cas du plâtre, sera de l'ordre de 45 degrés. Ce couloir 22 est disposé de telle sorte que son extrémité la plus basse surplombe la cuve 1 du mélangeur M et que le solide pulvérulent qu'il délivre tombe au centre de la cuve 1 sur la turbine 3.2 shows a complete mixing installation. We find the mixer M with its tank 1, its core 7 forming an obstacle inside the converging part 2 of the tank, its intermediate bottom 6 constituted by the upper surface of the core 7 , its annular flow orifice at the periphery of the intermediate bottom 6, its ejection device 8 in the form of an inverted cyclone, the collection pipe 11 extended vertically and provided with the valve 12 for adjusting the flow rate of the outgoing mixture, the liquid supply with the spillway 14 and the bypass 16, the turbine 3 driven by the motor 5. This FIG. 2 gives an example of a device S for supplying powdery solid and a device L for supplying liquid to the mixer M. The solid supply device S proposed here comprises a hopper 18 disposed above a conveyor belt 19 forming a balance, balanced on a knife shown diagrammatically at 20 when it is loaded with a determined weight of product. Such a device is called a constant weight apis-balance. This balance carpet 19 is associated with a hatch 21 for adjusting the thickness of the layer of product delivered by the hopper 18. A vibrating metal corridor 22 provided with a sieve is arranged below the end of the carpet. balance 19. This corridor 22 is inclined with respect to the horizontal by an angle which depends on the pulverulent product and which, in the case of plaster, will be of the order of 45 degrees. This corridor 22 is arranged so that its lowest end overhangs the tank 1 of the mixer M and the pulverulent solid which it delivers falls in the center of the tank 1 on the turbine 3.

Dans le dispositif d'alimentation en liquide L de cette figure 2, l'alimentation en liquide est faite à partir d'un réservoir 23 à niveau constant; un réglage du débit du liquide est effectué par une vanne 24 , un indicateur de débit 25 permet le contrôle précis dudit débit.In the liquid supply device L of this FIG. 2, the liquid supply is made from a reservoir 23 at constant level; the liquid flow is adjusted by a valve 24, a flow indicator 25 allows precise control of said flow.

L'installation de mélangeage fonctionne de la manière que nous allons décrire ci-après. Nous prendrons le plâtre com-je exemple de solide pulvérulent et l'eau comme exemple de liquide.The mixing plant operates as described below. We will take plaster as an example of a powdery solid and water as an example of liquid.

Avant démarrage, un rapport pondéral de mélange eau , Eo , est plâtre Po choisi, Eo et Po étant respectivement le débit massique d'eau et le débit massique de plâtre . Un rapport de 0,8 sera classiquement employé.Les débits de matière sont d'abord réglés.Before start-up, a water mixture weight ratio, Eo, is plaster Po chosen, Eo and Po being respectively the mass flow of water and the mass flow of plaster. A ratio of 0.8 will be conventionally used. The material flow rates are first regulated.

Le débit d'eau est réglé par la vanne 24 à la valeur Eo désirée. Le débit de plâtre est réglé ensuite à la valeur Po: le plâtre contenu dans la trémie 18 se répand sur le tapis-balance à poids constant 19 réglé en équilibre sur le couteau 20 pour un poids déterminé de produit, puis le débit Po est obtenu par le réglage de la vitesse de défilement du tapis-balance 19. Un temps de séjour To du plâtre mélangé dans la cuve du mélangeur est choisi. La turbine 3 est mise en rotation.La cuve du mélangeur est fermée par obstruction du tuyau 13 ou par fermeture de la vanne 12. Le dispositif L d'alimentation en liquide, réglé pour fournir un débit Eo, est ouvert pendant le temps To choisi. L'eau est introduite d'une part par le déversoir 14, d'autre part par le tuyau 16. La turbine 3 tournant à grande vitesse crée une agitation de l'eau. Au bout du temps To, l'alimentation en eau est coupée. Puis, le dispositif S d'alimentation en plâtre, réglé pour un débit Po, est mis en fonctionnement pendant un temps To. Au bout du temps To, l'alimentation en plâtre est coupée.The water flow rate is adjusted by the valve 24 to the desired Eo value. The plaster flow is then adjusted to the value Po: the plaster contained in the hopper 18 spreads on the constant weight balance carpet 19 adjusted in equilibrium on the knife 20 for a determined weight of product, then the flow Po is obtained by adjusting the running speed of the weighing belt 19. A residence time To of the plaster mixed in the mixer tank is chosen. The turbine 3 is set in rotation. The mixer tank is closed by obstruction of the pipe 13 or by closure of the valve 12. The device L for supplying liquid, adjusted to provide a flow rate Eo, is open for the time chosen To . Water is introduced on the one hand by the weir 14, on the other hand by the pipe 16. The turbine 3 rotating at high speed creates agitation of the water. At the end of time To, the water supply is cut off. Then, the plaster supply device S, adjusted for a flow rate Po, is put into operation for a time To. At the end of the time To, the plaster supply is cut off.

On laisse la turbine 3 mélanger l'eau et le plâtre pendant un temps de l'ordre de To/2 compté à partir de la coupure d'alimentation en plâtre. Puis, après ce temps To/2 de mélangeage, simultanément, on ouvre l'alimentation en eau toujours réglée pour un débit Eo, on ouvre l'alimentation toujours réglée pour un débit Po, on laisse s'écouler le mélange contenu dans la cuve du mélangeur en débouchant le tuyau 13 ou en ouvrant la vanne 12 de réglage du débit d'évacuation du mélange et en réglant ladite vanne 12 pour que la quantité de produit dans le mélangeur reste constante et égale à la quantité présente dans la cuve au cours du démarrage pendant la phase du mélangeage. Le régime permanent est ainsi rapidement atteint. L'alimentation en eau et en plâtre est continue avec des débits respectifs Eo et Po, le mélangeage est permanent, une quantité constante de mélange subsiste dans la cuve du mélangeur, le temps moyen de séjour du mélange dans le mélangeur est constant et égal à To choisi au démarrage, l'écoulement du mélange se fait lui aussi en continu avec un débit (Eo + Po).The turbine 3 is allowed to mix the water and the plaster for a time of the order of To / 2 counted from the cut of the plaster supply. Then, after this mixing time To / 2, simultaneously, we open the water supply always set for a flow rate Eo, we open the supply always set for a flow rate Po, we let the mixture flow into the tank of the mixer by opening the pipe 13 or by opening the valve 12 for adjusting the discharge rate of the mixture and by adjusting said valve 12 so that the quantity of product in the mixer remains constant and equal to the quantity present in the tank during starting during the mixing phase. The steady state is thus quickly reached. The water and plaster supply is continuous with respective flow rates Eo and Po, the mixing is permanent, a constant quantity of mixture remains in the mixer tank, the average residence time of the mixture in the mixer is constant and equal to To chosen at start-up, the flow of the mixture is also done continuously with a flow rate (Eo + Po).

L'eau introduite dans le déversoir annulaire 14 se répartit uniformément sur toute sa périphérie et par débordement ruisselle le long de la paroi intérieure de la cuve 1. L'eau prélevée par le tuyau 16, dosée par la vanne 17 réalise un arrosage de l'arbre 4 de la turbine 3. Le plâtre contenu dans la trémie 18 se répand sur le tapis-balance à poids constant 19 en équilibre sur le couteau 20. Le tapis-balance étant réglé pour un débit Po, toute suralimentation ou sous-alimentation momentanée en plâtre provoque un déséquilibre qui entraîne une modification de position de la trappe 21 de réglage de l'épaisseur de la couche de plâtre, modification qui tend à rétablir l'équilibre.The water introduced into the annular spillway 14 is distributed uniformly over its entire periphery and by overflow trickles along the inner wall of the tank 1. The water withdrawn by the pipe 16, metered by the valve 17 performs a sprinkling of the 'shaft 4 of the turbine 3. The plaster contained in the hopper 18 spreads on the constant weight balance carpet 19 in equilibrium on the knife 20. The balance carpet being adjusted for a flow Po, any overfeeding or underfeeding momentary plaster causes an imbalance which results in a change in position of the hatch 21 for adjusting the thickness of the plaster layer, a change which tends to restore balance.

En bout de tapis-balance 19, le plâtre tombe sur le tamis recouvrant le couloir métallique vibrant 22, les amas se brisent et le plâtre finement divisé s'écoule dans ledit couloir métallique. Celui-ci par ses vibrations, étale dans le temps les excès et les défauts à l'alimentation du plâtre, dus au processus d'éboulement; puis il concentre le plâtre en une veine et fait chuter ladite veine sur la turbine 3 qui tourne à grande vitesse à l'intérieur de la cuve 1 du mélangeur. Le rideau d'eau formé sur la paroi de la cuve 1 et l'excès d'eau créé sur l'arbre de la turbine empêchent tout dépôt de plâtre pulvérulent et toute amorce indésirable de prise en masse sur la paroi de la cuve 1 et sur l'arbre 4.At the end of the weighing carpet 19, the plaster falls on the sieve covering the vibrating metal corridor 22, the clusters break and the finely divided plaster flows in said metal corridor. The latter, by its vibrations, spreads over time the excesses and defects in the plaster supply, due to the landslide process; then it concentrates the plaster in a vein and causes the said vein to drop onto the turbine 3 which rotates at high speed inside the tank 1 of the mixer. The curtain of water formed on the wall of the tank 1 and the excess water created on the shaft of the turbine prevent any deposit of powdered plaster and any undesirable primer of solidification on the wall of the tank 1 and on the tree 4.

La turbine 3 tournant à grande vitesse met en rotation les produits contenus dans la cuve. La vitesse de la turbine est déterminée pour qu'il se forme un vortex stable à axe vertical, c'est-à-dire un seul tourbillon creux habillant intérieurement les parois de la cuve.The turbine 3 rotating at high speed rotates the products contained in the tank. The speed of the turbine is determined so that a stable vortex with a vertical axis is formed, that is to say a single hollow vortex lining the walls of the tank internally.

La surface du mélange prend alors une forme conique centrée sur l'arbre 4 de la turbine 3.The surface of the mixture then takes a conical shape centered on the shaft 4 of the turbine 3.

La profondeur du vortex dépend de la géométrie de la cuve du mélangeur M et de la vitesse de rotation de la turbine 3 que l'on règle pour que le fond du tourbillon touche ladite turbine 3. Cette vitesse optimale dépend de la fluidité du mélange, laquelle est fonction du rapport Eo et de To. Po The depth of the vortex depends on the geometry of the tank of the mixer M and on the speed of rotation of the turbine 3 which is adjusted so that the bottom of the vortex touches said turbine 3. This optimal speed depends on the fluidity of the mixture, which is a function of the ratio Eo and To. Po

Une vitesse insuffisante produira un recouvrement excessif de la turbine par le mélange et une surface trop plane du mélange sur laquelle pourront subsister des amas de solide non dispersés dans l'eauAn insufficient speed will produce an excessive covering of the turbine by the mixture and an excessively flat surface of the mixture on which may remain clumps of solid not dispersed in water

Au contraire, une vitesse trop importante aura tendance à creuser excessivement le vortex jusqu'à découvrir toute la turbine 3 et à faire monter le mélange trop haut le long de la paroi de la cuve 1, celui-ci retombant alors périodiquement sur la turbine, entraînant ainsi un mouvement de rotation irréguliEr.On the contrary, too high a speed will tend to dig the vortex excessively until the entire turbine 3 is uncovered and to cause the mixture to rise too high along the wall of the tank 1, the latter then falling periodically onto the turbine, thus causing an irregular rotational movement.

Le plâtre pulvérulent délivré par le couloir métallique vibrant 22 tombe au centre du vortex sur la turbine 3 tournant à grande vitesse.The powdery plaster delivered by the vibrating metal corridor 22 falls in the center of the vortex on the turbine 3 rotating at high speed.

Il est instantanément dispersé et projeté dans le mélange préexistant dans la cuve 1.It is instantly dispersed and sprayed into the preexisting mixture in tank 1.

La rotation des produits assure l'homogénéisation, et l'inclinaison de la surface du liquide évite la stagnation de produits solides en amas. Le fond intermédiaire 6 du mélangeur M constitué par la surface supérieure du noyau 7 épousant les figures d'écoulement de la turbine 3, c'est-à-dire les lignes de circulation de la zone de mélangeage, et étant par exemple plat et disposé à proximité immédiate de la turbine, aucun dépôt ne s'y forme.Le mélange plâtre/eau s'extrait de façon régulière dans l'espace annulaire situé entre le noyau-obstacle 7 et la paroi convergente de la partie basse 2 du mélangeur.La position de ce noyau 7 par rapport à la paroi convergente de la partie basse 2 du mélangeur définit les dimensions de cet espace annulaire et détermine ainsi un certain débit d'écoulement limite. Le mélange s'écoule dans cet espace avec une vitesse suffisante qui ne permet pas les prises en masse. Dans le cas où le noyau 7 est un cône et où la paroi extérieure de la partie convergente 2 du mélangeur est elle-même conique, la vitesse du mélange de plâtre mesurée le long de la génératrice du noyau en cône 7 sera au moins de 30 cm/seconde et généralement de l'ordre de 1 m/seconde. Les sections des tuyauteries d'extraction du mélange situées en aval seront également choisies puur que l'on y atteigne cette vitesse minimale évitant ainsi les dépôts et une prise en masse prématurée.The rotation of the products ensures homogenization, and the inclination of the surface of the liquid avoids the stagnation of solid products in clusters. The intermediate bottom 6 of the mixer M constituted by the upper surface of the core 7 conforming to the flow patterns of the turbine 3, that is to say the circulation lines of the mixing zone, and being for example flat and arranged There is no deposit in the immediate vicinity of the turbine. The plaster / water mixture is extracted regularly in the annular space between the obstacle-core 7 and the converging wall of the lower part 2 of the mixer. The position of this core 7 with respect to the converging wall of the lower part 2 of the mixer defines the dimensions of this annular space and thus determines a certain limit flow rate. The mixture flows in this space with a sufficient speed which does not allow solidification. In the case where the core 7 is a cone and the outer wall of the converging part 2 of the mixer is itself conical, the speed of the plaster mixture measured along the generatrix of the cone core 7 will be at least 30 cm / second and generally around 1 m / second. The sections of the mixture extraction pipes located downstream will also be chosen for reaching this minimum speed, thus avoiding deposits and premature caking.

Le mélange converge à la pointe 2' de la partie basse 2 du mélangeur. Le mélange toujours en circulation rotationnelle pénètre dans le dispositif d'éjection 8 en forme de cyclone inversé.Le mélange reste plaqué le long des parois coniques du dispositif d'éjection 8 et descend le long de ces parois jusqu'à la base 10 du dispositif en décrivant une spirale. De cette façon, il ne se forme pas de tourbillon non contrôlé pouvant donner lieu à une zone morte où risquerait de se produire une prise en masse. Le mélange en circulation rotationnelle est ensuite capté par le tuyau de captage 11 et il donne alors une veine cylindrique pleine dont le débit sera désormais susceptible d'être réglé de façon précise par la vanne à étranglement située à l'extrémité dudit tuyau de captage 11.The mixture converges at the tip 2 'of the lower part 2 of the mixer. The mixture still in rotational circulation enters the ejection device 8 in the form of an inverted cyclone. The mixture remains pressed along the conical walls of the ejection device 8 and descends along these walls to the base 10 of the device. by describing a spiral. In this way, an uncontrolled vortex does not form, which can give rise to a dead zone where there is a risk of solidification. The mixture in rotational circulation is then captured by the collection pipe 11 and it then gives a full cylindrical stream whose flow will now be able to be adjusted precisely by the throttling valve located at the end of said collection pipe 11 .

Les débits d'alimentation Po et Eo n'étant cependant pas parfaitement stables et pouvant subir des fluctuations qui entraîneraient des fluctuations de fluidité du mélange, la section de passage de cette vanne 22 est constamment ajustée pour maintenir une quantité constante de mélange dans la cuve du mélangeur et par là même un temps de séjour constant dudit mélange dans ledit mélangeur. Ce temps de séjour permet l'homogénéisation du mélange et la suppression des irrégularités d'alimentation.The feed rates Po and Eo however not being perfectly stable and being able to undergo fluctuations which would cause fluctuations in the fluidity of the mixture, the passage section of this valve 22 is constantly adjusted to maintain a constant quantity of melan ge in the mixer tank and thereby a constant residence time of said mixture in said mixer. This residence time allows the homogenization of the mixture and the elimination of feed irregularities.

Le réglage de la vanne 12 pourra être obtenu de diverses façons. Il pourrait être manuel, mais dans le cas du plâtre, compte tenu du processus rapide d'évolution du plâtre pulvérulent dès qu'il est en contact avec l'eau, si l'on veut disposer d'un mélange à fluidité constante, ayant donc séjourné un temps bien précis dans le mélangeur, il sera automatique. Le signal de régulation envoyé à la vanne 12 sera fourni par une cellule photo-électrique réagissant dès que le mélange dans la cuve du mélangeur aura atteint un certain niveau, ou par un système capacitif mesurant la capacité électrique d'une hauteur déterminée du mélange, ou par une sonde de pression disposée au fond de la cuve, ou encore préférentiL- lement par pesée du mélangeur.The adjustment of valve 12 can be obtained in various ways. It could be manual, but in the case of plaster, taking into account the rapid process of evolution of powdered plaster as soon as it is in contact with water, if one wants to have a mixture with constant fluidity, having so stayed a specific time in the mixer, it will be automatic. The regulation signal sent to valve 12 will be provided by a photoelectric cell reacting as soon as the mixture in the mixer tank has reached a certain level, or by a capacitive system measuring the electrical capacity of a determined height of the mixture, or by a pressure probe placed at the bottom of the tank, or preferably by weighing the mixer.

La vanne 12 sera une vanne à passage direct constituée par un corps rigide, par un manchon intérieur élastique et par une amenée de fluide entre le corps rigide et le manchon, ledit fluide étant susceptible de comprimer le manchon élastique pour diminuer le débit de la vanne. Pour éviter tout dépôt et toute prise en masse du plâtre au niveau de l'étranglement de la vanne 12, on produit une modulation de la pression du fluide commandant l'ouverture de la vanne 12, modulation qui fait se déformer constamment le manchon.The valve 12 will be a direct passage valve constituted by a rigid body, by an elastic inner sleeve and by a fluid supply between the rigid body and the sleeve, said fluid being capable of compressing the elastic sleeve to reduce the flow rate of the valve. . To avoid any deposit and any solidification of the plaster at the throttle of the valve 12, a modulation of the pressure of the fluid controlling the opening of the valve 12 is produced, modulation which causes the sleeve to constantly deform.

Avantageusement, pour favoriser les déformations, le manchon sera constitué d'une matière imperméable élastique , souple, telle que du caoutchouc de chambre à air et il aura au repos sensiblement les mêmes dimensions que l'intérieur du corps rigide qui l'enveloppe.Advantageously, to promote deformations, the sleeve will be made of an elastic, flexible impermeable material, such as air chamber rubber and it will have at rest substantially the same dimensions as the interior of the rigid body which envelops it.

Avantageusement, on commandera la vanne 12 à l'aide d'un système pneumatique de régulation à fuite faisant varier l'ouverture de ladite vanne 12 en fonction du poids du mélangeur et on profitera des oscillations du système induites par les vibrations dues au mouvement du mélange et de la turbine dans la cuve du mélangeur pour moduler la pression du fluide de commande. Plus spécialement dans ce cas le mélangeur sera désolidarisé des installations amont et aval pour rendre la pesée possible. Un tel système pneumatique à fuite comporte principalement un circuit pneumatique et un fléau de balance de forces. Le circuit pneumatique est alimenté avec un débit constant d'air comprimé; il comporte deux dérivations, l'une allant à la vanne 12, l'autre débouchant à l'air libre à proximité d'une extrémité du fléau de balance et déterminant ainsi une certaine fuite, variable lorsque le fléau oscille. Le fléau de balance pèse en permanence le mélangeur. Il est mis à l'équilibre pour un poids déterminé du mélangeur grâce à un ressort de rappel et à un contrepoids de tarage réglable et il oscille lorsque ce poids varie. Il fait alors augmenter ou diminuer la fuite du circuit pneumatique et par contrecoup, respectivement diminuer ou augmenter la pression de l'air dirigé sur la vanne, modifiant ainsi la section de passage de la vanne et par conséquent le débit d'évacuation du mélangeur. En outre, les mouvements du mélange et les vibrations de la turbine font légèrement osciller le fléau en permanence; et ce sont ces oscillations légères, qui, détectées par le circuit pneumatique, engendrent la modulation de pression du fluide commande de la vanne. Le manchon élastique de la vanne recevant en plus de son signal de régulation un signal pulsatoire résultant des vibrations induites par la turbine se déforme constamment, empêchant ainsi tout dépôt de plâtre.Advantageously, the valve 12 will be controlled using a pneumatic leakage control system varying the opening of said valve 12 as a function of the weight of the mixer and we will take advantage of the system's oscillations induced by the vibrations due to the movement of the mixture and the turbine in the mixer tank to modulate the pressure of the control fluid. More specifically in this case the mixer will be separated from the upstream and downstream installations to make weighing possible. Such a pneumatic leak system mainly comprises a pneumatic circuit and a force balance beam. The pneumatic circuit is supplied with a constant flow of compressed air; it comprises two branches, one going to the valve 12, the other opening into the open air near one end of the balance beam and thus determining a certain leak, variable when the beam oscillates. The Scourge of Balance weighs the mixer continuously. It is balanced for a specific weight of the mixer thanks to a return spring and an adjustable calibration counterweight and it oscillates when this weight varies. It then increases or decreases the leakage from the pneumatic circuit and by backlash, respectively decreases or increases the pressure of the air directed onto the valve, thus modifying the passage section of the valve and consequently the discharge rate of the mixer. In addition, the movements of the mixture and the vibrations of the turbine cause the beam to oscillate slightly continuously; and it is these light oscillations, which, detected by the pneumatic circuit, generate the pressure modulation of the valve control fluid. The elastic sleeve of the valve receiving in addition to its regulation signal a pulsating signal resulting from the vibrations induced by the turbine is constantly deformed, thus preventing any plaster deposit.

Le dispositif d'éjection pourra être constitué par n'importe quel moyen classique en mécanique des fluides, capable de transformer un flux quelconque, en particulier un flux rotationnel, en une veine pleine. Ainsi, on pourra utiliser une couronne d'impact 26 formée par un pot pos- sédar-t un fond et un tube latéral d'éjection.The ejection device can be constituted by any conventional means in fluid mechanics, capable of transforming any flow, in particular a rotational flow, into a solid vein. Thus, it will be possible to use an impact crown 26 formed by a pot pos- sedar a bottom and a lateral ejection tube.

Le temps To doit toujours rester inférieur à une valeur Tp correspondant au temps de début de prise du mélange. Des débits d'alimentation Po et

Figure imgb0002
de ce fait le débit d'évacuation (Po + Eo) étant déterminés, ce temps moyen de rétention To est déterminé par l'état de remplissage de la cuve de mélangeage et c'est par le maintien de cet état de remplissage que l'on conserve constant le temps moyen de rétention. Le temps moyen de rétention sera au moins égal à trois secondes et préférentiellement compris entre 15 et 30 secondes pour que soit obtenue une homogénéisation suffisante des produits solides et liquides.The time To must always remain lower than a value Tp corresponding to the time of start of setting of the mixture. Feed rates Po and
Figure imgb0002
therefore the discharge flow rate (Po + Eo) being determined, this mean retention time To is determined by the filling state of the mixing tank and it is by maintaining this filling state that the the average retention time is kept constant. The average retention time will be at least equal to three seconds and preferably between 15 and 30 seconds so that sufficient homogenization of the solid and liquid products is obtained.

Il a été décrit jusqu'à maintenant le mélangeage du plâtre et de l'eau, mais le procédé reste identique et le dispositif fonctionne de la même façon si l'on introduit des additifs à l'une quelconque des différentes étapes du mélangeage, le mot additif désignant des produits réactifs ou inertes, solides ou liquides, de préférence finement divisés lorsqu'ils sont solides. On pourra ainsi introduire des additifs solides avec le plâtre pulvérulent, soit que l'ajout ait été fait préalablement par le fabricant de plâtre, soit que l'on distribue ledit additif dans la trémie 18 ou sur le tapis-balance 19. On pourra aussi introduire des additifs solides ou liquides dans l'eau, ou bien encore directement dans le mélangeur. Lesdits additifs peuvent consister en des adjuvants chimiques ou des éléments de renfort du plâtre tels que des fibres coupées ou finement divisées.Mixing plaster and water has so far been described, but the process remains the same and the device works in the same way if additives are introduced at any of the different stages of mixing, additive word designating reactive or inert products, solid or liquid, preferably finely divided when they are solid. It will thus be possible to introduce solid additives with the pulverulent plaster, either because the addition has been made beforehand by the plaster manufacturer, or by distributing said additive in the hopper 18 or on the weighing carpet 19. also introduce solid or liquid additives into the water, or even directly into the mixer. Said additives may consist of adjuvants chemical or reinforcing elements of plaster such as cut or finely divided fibers.

Il faut donc prendre les mots "plâtre pulvérulent" et "eau" dans un sens plus général,et il est préférable de parler de phase solide ou de solide pour désigner aussi bien le plâtre pulvérulent seul que le mélange de plâtre avec d'autres solides, et de parler de phase liquide ou de liquide pour désigner l'eau seule aussi bien que l'eau contenant des additifs solides ou liquides.It is therefore necessary to take the words "pulverulent plaster" and "water" in a more general sense, and it is preferable to speak of solid phase or solid to designate both pulverulent plaster alone and the mixture of plaster with other solids , and to speak of liquid or liquid phase to designate water alone as well as water containing solid or liquid additives.

Claims (30)

1. Procédé de mélangeage en continu de solides pulvérulents et de liquides, notamment du plâtre et de.l'eau essentiellement, caractérisé en ce qu'il consiste: - à introduire en continu la phase liquide dans une cuve de mélangeage ; - à introduire en continu la phase solide dans ladite cuve avec un débit tel que soient respectées les proportions désirées de solide et de liquide dans le mélange; - à assurer la rotation des produits contenus dans la cuve de façon à former un vortex; - à régler les débits d'alimentation en solide et en liquide pour que se maintienne constamment un certain état de remplissage de la cuve; - à évacuer en continu le mélange des produits pour que se conserve cet état de remplissage. 1. Process for the continuous mixing of pulverulent solids and liquids, in particular plaster and de.l'eau essentially, characterized in that it consists: - continuously introducing the liquid phase into a mixing tank; - Continuously introducing the solid phase into said tank at a rate such that the desired proportions of solid and liquid in the mixture are respected; - ensuring the rotation of the products contained in the tank so as to form a vortex; - to regulate the flow rates of solid and liquid so that a certain state of filling of the tank is constantly maintained; - to continuously evacuate the mixture of products so that this filling state remains. 2. Procédé de mélangeage selon la revendication 1, caractérisé en ce que sa période de démarrage comporte les étapes suivantes: . introduction, dans la cuve de mélangeage, du liquide et du solide dans les proportions du rapport de mélange préalablement choisi, jusqu'à atteindre un certain niveau de remplissage de ladite cuve de mélangeage; . mise en rotation dans la cuve des produits introduits et maintien de la relation pendant un temps déterminé; puis simultanément: . admission en continu dans la cuve,du liquide et du solide avec des débits tels que soit respecté le rapport pondéral de mélange, . évacuation en continu du mélange avec un débit tel que se conserve le niveau de remplissage. 2. Mixing method according to claim 1, characterized in that its start-up period comprises the following stages: . introduction, into the mixing tank, of the liquid and the solid in the proportions of the previously selected mixing ratio, until a certain level of filling of said mixing tank is reached; . rotation in the tank of the products introduced and maintenance of the relationship for a determined time; then simultaneously: . continuous admission into the tank of liquid and solid with flow rates such that the mixing weight ratio is respected, . continuous discharge of the mixture at a rate such that the filling level remains. 3. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que le rapport pondéral de mélange E est de l'ordre de 80 . 1003. Method according to any one of the preceding claims, characterized in that the weight ratio of mixture E is of the order of 80. 100 4. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que le temps de séjour moyen des produits à mélanger dans la cuve de mélangeage est déterminé par l'état de remplissage de ladite cuve.4. Method according to any one of the preceding claims, characterized in that the average residence time of the products to be mixed in the mixing tank is determined by the filling state of said tank. 5. Procédé selon la revendication 4, caractérisé en ce que le temps de séjour moyen des produits à mélanger dans la cuve de mélangeage est au moins égal à 3 secondes et préférentiellement compris entre 15 et 30 s.5. Method according to claim 4, characterized in that the average residence time of the products to be mixed in the mixing tank is at least equal to 3 seconds and preferably between 15 and 30 s. 6. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que l'évacuation du mélange se fait par la périphérie de la cuve de mélangeage.6. Method according to any one of the preceding claims, characterized in that the evacuation of the mixture is done by the periphery of the mixing tank. 7. Procédé selon l'une des revendications précédentes, caractérisé en ce que l'évacuation se fait au travers du fond de la cuve de mélangeage.7. Method according to one of the preceding claims, characterized in that the evacuation takes place through the bottom of the mixing tank. 8. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que le liquide est introduit le long des parois de la cuve de mélangeage, sur tout son pourtour, de façon à y former un rideau continu de liquide.8. Method according to any one of the preceding claims, characterized in that the liquid is introduced along the walls of the mixing tank, around its entire periphery, so as to form there a continuous curtain of liquid. 9. Procédé selon l'une quelconque des revendications précédentes,caractérisé en ce que le solide pulvérulent est introduit au centre du vortex du liquide.9. Method according to any one of the preceding claims, characterized in that the pulverulent solid is introduced into the center of the vortex of the liquid. 10. Procédé selon l'une quelconque des revendications précédentes,caractérisé en ce que des additifs solides ou liquides sont introduits dans le liquide.10. Method according to any one of the preceding claims, characterized in that solid or liquid additives are introduced into the liquid. 11. Procédé selon l'une quelconque des revendications précédentes,caractérisé en ce que des additifs solides ou liquides sont introduits dans le mélangeur.11. Method according to any one of the preceding claims, characterized in that solid or liquid additives are introduced into the mixer. 12. Procédé selon l'une quelconque des revendications précédentes,caractérisé en ce que des additifs solides sont introduits dans le solide.12. Method according to any one of the preceding claims, characterized in that solid additives are introduced into the solid. 13. Mélangeur vertical du type cuve pour solides pulvérulents et liquides, caractérisé en ce qu'il comprend: - une cuve formée par un solide de révolution creux muni à son extrémité inférieure d'un orifice d'écoulement équipé de moyens de réglage du débit d'écoulement, ladite cuve possédant une paroi intérieure ajourée qui constitue un fond intermédiaire; - une turbine disposée à l'intérieur de la cuve au-dessus du fond intermédiaire et tournant autour d'un axe vertical situé suivant l'axe de la cuve; - des moyens d'alimentation en liquide; - des moyens d'alimentation en solide. 13. Vertical mixer of the tank type for pulverulent solids and liquids, characterized in that it comprises: - A tank formed by a hollow solid of revolution provided at its lower end with a flow orifice equipped with means for adjusting the flow rate, said tank having an perforated inner wall which constitutes an intermediate bottom; - a turbine placed inside the tank above the intermediate bottom and rotating around a vertical axis located along the axis of the tank; - means for supplying liquid; - solid feed means. 14. Mélangeur selon la revendication 13, caractérisé en ce que la turbine est une turbine défloculeuse.14. Mixer according to claim 13, characterized in that the turbine is a deflocculating turbine. 15. Mélangeur selon l'une quelconque des revendications 13 ou 14, caractérisé en ce que le fond intermédiaire présente une surface supérieure dont la forme épouse les lignes de circulation de la zone de mélangeage supérieure.15. Mixer according to any one of claims 13 or 14, characterized in that the intermediate bottom has an upper surface whose shape matches the circulation lines of the mete zone superior change. 16. Mélangeur selon l'une quelconque des revendications 13, 14 ou 15, caractérisé en ce que le fond intermédiaire prasente une surface supérieure plane perpendiculaire à l'axe de la cuve, disposée à proximité immédiate de la turbine.16. Mixer according to any one of claims 13, 14 or 15, characterized in that the intermediate bottom has a flat upper surface perpendicular to the axis of the tank, disposed in the immediate vicinity of the turbine. 17. Mélangeur selon l'une quelconque des revendications 13 à 16, caractérisé en ce que le fond intermédiaire est ajouré à sa périphérie.17. Mixer according to any one of claims 13 to 16, characterized in that the intermediate bottom is perforated at its periphery. 18. Mélangeur selon l'une quelconque des revendications 16 ou 17, caractérisé en ce que le fond intermédiaire présente une paroi circulaire centrée sur l'axe de la cuve et de diamètre inférieur au diamètre intérieur de ladite cuve, les jours de ce fond intermédiaire étant réalisés par l'intervalle qui existe entre ledit fond et la paroi latérale de la cuve.18. Mixer according to any one of claims 16 or 17, characterized in that the intermediate bottom has a circular wall centered on the axis of the tank and of diameter less than the inside diameter of said tank, on the days of this intermediate bottom being produced by the gap which exists between said bottom and the side wall of the tank. 19. Mélangeur selon l'une quelconque des revendications 13 à 18, caractérisé en ce que la cuve de mélangeage a la forme d'un cylindre vertical prolongé vers le bas par une partie qui se rétrécit pour converger vers l'orifice d'écoulement.19. Mixer according to any one of claims 13 to 18, characterized in that the mixing tank has the shape of a vertical cylinder extended downwards by a part which narrows to converge towards the flow orifice. 20. Mélangeur suivant la revendication 19, caractérisé en ce que le t'ond intermédiaire est situé au niveau de la jonction du cylindre avec la partie basse rétrécie et convergente de la cuve.20. Mixer according to claim 19, characterized in that the intermediate wave is located at the junction of the cylinder with the narrowed and converging lower part of the tank. 21. Mélangeur suivant la revendication 20, caractérisé en ce que le fond intermédiaire est constitué par la surface supérieure d'un noyau ayant la forme d'un solide de révolution convergent vers le bas, disposé à l'intérieur de la partie basse convergente de la cuve, centré sur l'axe de ladite cuve, ledit noyau ayant une section inférieure à la section de la cuve de façon à réserver un intervalle annulaire entre lui et la paroi intérieure de ladite cuve.21. Mixer according to claim 20, characterized in that the intermediate bottom is constituted by the upper surface of a core having the shape of a solid of revolution converging downwards, disposed inside the converging lower part of the tank, centered on the axis of said tank, said core having a section smaller than the section of the tank so as to reserve an annular gap between it and the inner wall of said tank. 22. Mélangeur suivant la revendication 21, caractérisé en ce que le noyau disposé à l'intérieur de la partie basse de la cuve du mélangeur est un cône droit disposé pointe en bas, dont la base plane constitue le fond intermédiaire, la partie basse convergente de la cuve étant alors elle-même conique.22. Mixer according to claim 21, characterized in that the core disposed inside the lower part of the mixer tank is a straight cone arranged point downwards, the flat base of which constitutes the intermediate bottom, the converging lower part of the tank then being itself conical. 23. Mélangeur selon l'une quelconque des revendications 13 à 22, caractérisé en ce que les moyens de réglage du débit d'écoulement comportent une vanne à étranglement.23. Mixer according to any one of claims 13 to 22, characterized in that the means for adjusting the flow rate comprise a throttle valve. 24. Mélangeur selon la revendication 23, caractérisé en ce que la vanne à étranglement est précédée par un dispositif d'éjection disposé sous l'orifice d'écoulement de la cuve de mélangeage et faisant corps avec ladite cuve , ledit dispositif recevant le mélange et transformant son écoulement en une veine pleine.24. Mixer according to claim 23, characterized in that the throttling valve is preceded by an ejection device disposed under the flow orifice of the mixing tank and being integral with said tank, said device receiving the mixture and transforming its flow in a full vein. 25. Mélangeur selon la revendication 24, caractérisé en ce que le dispositif d'éjection a la forme d'un cyclone inversé, c'est-à-dire est constitué par une enveloppe conique disposée pointe en haut avec une entrée à la pointe du cône, avec une base plane et avec un tuyau de captage sortant au ras de ladite base, tangentiellement à l'enveloppe conique dans le sens de rotation de la turbine du mélangeur.25. Mixer according to claim 24, characterized in that the ejection device has the shape of an inverted cyclone, that is to say is constituted by a conical envelope arranged point up with an inlet at the point of the cone, with a flat base and with a collection pipe coming out flush with said base, tangentially to the conical casing in the direction of rotation of the mixer turbine. 26. Mélangeur selon la revendication 24, caractérisé en ce que le dispositif d'éjection est une couronne d'impact formée d'un pot vertical avec fond et tuyau latéral de sortie.26. Mixer according to claim 24, characterized in that the ejection device is an impact ring formed of a vertical pot with bottom and lateral outlet pipe. 27. Mélangeur selon l'une quelconque des revendications 23 à 26 , caractérisé en ce que la vanne à étranglement est automatique et commandée par l'un des moyens suivants: cellule photoélectrique détectant le niveau du mélange dans la cuve du mélangeur, sonde de pression disposée sur le fond intérmédiaire de la cuve, système capacitif, bras de fléau pesant en permanence la cuve du mélangeur, la cuve du mélangeur étant dans ce dernier cas désolidarisée des installations amont et aval.27. Mixer according to any one of claims 23 to 26, characterized in that the throttle valve is automatic and controlled by one of the following means: photoelectric cell detecting the level of the mixture in the mixer tank, pressure probe arranged on the intermediate bottom of the tank, capacitive system, beam arm permanently weighing the mixer tank, the mixer tank being in the latter case separated from the upstream and downstream installations. 28. Mélangeur selon l'une quelconque des revendications 13 à 27, caractérisé en ce que les moyens d'alimentation en solide pulvérulent comportent : - une trémie d'alimentation munie d'une trappe de réglage du débit; - un tapis-balance à poids constant sur lequel est déversé le solide; pulvérulent de la trémie et dont le déséquilibre provoque une modification de la position de la trappe de réglage; - un régularisateur d'écoulement du solide pulvérulent délivré par le tapis-balance, ledit régularisateur étant constitué par une goulotte vibrante. 28. Mixer according to any one of claims 13 to 27, characterized in that the means for supplying pulverulent solid comprise: - a feed hopper fitted with a flow adjustment hatch; - a constant weight balance carpet onto which the solid is poured; powder from the hopper and whose imbalance causes a change in the position of the adjustment flap; - A flow regulator for the powdery solid delivered by the weighing belt, said regulator being constituted by a vibrating chute. 29. Mélangeur selon l'une quelconque des revendications 12 à 27, caractérisé en ce que les moyens d'alimentation en liquide comportent: - un déversoir annulaire recouvrant le bord supérieur de la cuve et distribuant le liquide le long des parois latérales de la cuve; - un tube dirigé sur l'arbre de la turbine; - une vanne de réglage du débit. 29. Mixer according to any one of claims 12 to 27, characterized in that the liquid supply means comprise: - an annular weir covering the upper edge of the tank and distributing the liquid along the side walls of the tank; - a tube directed on the turbine shaft; - a flow adjustment valve. 30. Mélangeur selon l'une quelconque des revendications 12 à 28, caractérisé en ce que la turbine est disposée à proximité immédiate de la surface supérieure du fond intermédiaire.30. Mixer according to any one of claims 12 to 28, characterized in that the turbine is arranged in the immediate vicinity of the upper surface of the intermediate bottom.
EP79400077A 1978-02-08 1979-02-06 Method of and apparatus for continuously mixing powdery solids and liquids, especially plaster with water Expired EP0003704B1 (en)

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US1781255A (en) * 1929-04-24 1930-11-11 Independent Oil Well Cementing Cement mixer for cementing oil and gas wells
US2915412A (en) * 1957-03-15 1959-12-01 Georgia Kaolin Co Method of handling and conditioning paper making clay for use
US3222036A (en) * 1963-02-07 1965-12-07 Arvel O Franz Apparatus for preparation of solids in liquid dispersions
FR1525094A (en) * 1966-04-18 1968-05-17 Method and device for the preparation of cement and concrete mortar
US3967815A (en) * 1974-08-27 1976-07-06 Backus James H Dustless mixing apparatus and method for combining materials
DE2602858A1 (en) * 1975-02-05 1976-08-19 Melyepitesi Tervezo Vallalat Slurry mixer for hydraulic conveying - having mixing zone inside vessel with recycle of weak slurry

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0022738A1 (en) * 1979-07-17 1981-01-21 Arbed S.A. Process for the manufacture of colloidal mortar and product obtained by this process
WO1994026401A1 (en) * 1993-05-18 1994-11-24 Explosive Developments Limited Mixing arrangements
EP0627287A1 (en) * 1993-06-04 1994-12-07 Halliburton Company Continuous production of multi-component slurry
EP2086735A2 (en) * 2006-11-01 2009-08-12 United States Gypsum Company Apparatus and method for wet mixing cementitious slurry for fiber-reinforced structural cement panels
EP2086735A4 (en) * 2006-11-01 2009-12-23 United States Gypsum Co Apparatus and method for wet mixing cementitious slurry for fiber-reinforced structural cement panels
US7754052B2 (en) 2006-11-01 2010-07-13 United States Gypsum Company Process and apparatus for feeding cementitious slurry for fiber-reinforced structural cement panels
WO2012028291A1 (en) * 2010-09-01 2012-03-08 Cargill, Incorporated Apparatus and method for mixing a powder with a liquid
MD363Z5 (en) * 2010-10-21 2011-11-30 Институт Сельскохозяйственной Техники "Mecagro" Device for dispensing and mixing liquids
CN108032437A (en) * 2017-12-15 2018-05-15 中科纳达新材料（广西）有限公司 A kind of concrete central mix plant for construction

Also Published As

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NO149683C (en) 1984-06-06
GR71690B (en) 1983-06-21
IE790225L (en) 1979-08-08
PL213285A1 (en) 1979-11-05
PL124781B1 (en) 1983-02-28
FR2416717A1 (en) 1979-09-07
EP0003704B1 (en) 1982-10-20
FI790410A (en) 1979-08-09
AR220370A1 (en) 1980-10-31
NZ189601A (en) 1983-05-10
CA1121804A (en) 1982-04-13
BR7900754A (en) 1979-08-28
ES477528A1 (en) 1979-06-16
DE2963867D1 (en) 1982-11-25
IN150658B (en) 1982-11-20
AU4403279A (en) 1979-08-16
FI63535B (en) 1983-03-31
DK45979A (en) 1979-08-09
JPS54117972A (en) 1979-09-13
ATA95679A (en) 1987-02-15
AU537609B2 (en) 1984-07-05
IE48227B1 (en) 1984-11-14
NO149683B (en) 1984-02-27
NO790386L (en) 1979-08-09
TR20998A (en) 1983-03-30
FR2416717B1 (en) 1982-03-19
FI63535C (en) 1983-07-11
ZA79519B (en) 1980-05-28
PT69198A (en) 1979-03-01

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