EP3231786A1 - Static mixer with a shearing device and method for producing explosive - Google Patents

Abstract

The present invention relates to a method for producing an explosive product in situ (10) comprising the steps of: 1) a matrix comprising an emulsion and a liquid product containing a gasification reagent is separately transferred to a first mixer (7), and 2) mixing said matrix, and said gasification reagent, in said first mixer (7) through which said matrix and gasification reagent are transferred as a mixture, and 3) transferring and depositing said explosive product obtained at the outlet of said first mixer, in an explosion hole (21), in or above which the downstream end of the first mixer is arranged, characterized in that prior to step 3), an increase in the viscosity of said mixture of said matrix and said shear gasification reagent is achieved within a tube or sheath tube (6, 7) in which said matrix and said gasification reagent are transferred, passing said mixture into a shearing device (10) within said pipe or tube (6,7).

Description

The present invention relates to the field of the preparation and use of explosive products including explosive emulsions used in the extraction of raw material and mining industry.

• une phase continue organique, constituée mélange de divers combustibles tel que huiles minérales, gasoil, et
• une phase aqueuse discontinue constituée de divers sels comburants en solution aqueuse.

These products are systematically constituted from a so-called inverse base emulsion or "water in oil" also called "matrix" obtained by a mixture of:

• an organic continuous phase, constituted mixture of various fuels such as mineral oils, gas oil, and
• a discontinuous aqueous phase consisting of various oxidizing salts in aqueous solution.

The most frequently used oxidizing raw materials in this industry are: ammonium nitrate, sodium nitrate, calcium nitrate. With regard to fuels, it is gas oil that is either pure or mixed with new or used mineral oils, especially recycled motor oil.

To give this mixture improved detonation characteristics, it is necessary, in known manner, to disperse homogeneously "porosities" within it. To date, the method mainly used in the industry for the sensitization of bulk or cartridge emulsions is chemical gasification. This consists in generating as chemically and as homogeneously as possible gas bubbles in the medium. The "porosities" thus obtained will form hot spots, initiators of the detonation and thus help maintain the propagation of a shock wave from the priming system.

The present invention relates to the manufacture of explosive charges from an emulsion or matrix that is sensitized by mixing with reagents that react with the emulsion and generate a chemical gasification.

More particularly, but without limitation, to react with ammonium of said emulsion matrix (hereinafter M), a gasification reagent (hereinafter R) based on sodium nitrite or equivalent is used. in the presence of a catalyst such as an acid, especially acetic acid of the following chemical reaction:

This chemical reaction generates in the product nitrogen gas bubbles which makes the product explosive and leads to a decrease in the final density of the mixture product obtained. Generally, we go from an initial density di of the matrix M di = 1 to 2 that we decrease to a value dj = 0.5 to 1.5 depending on the proportion of reagent R / M, typically di = 1.4 and dj = 1.2 at 0.9.

In the rest of the text herein is understood to mean a matrix or emulsion, the emulsion itself supplemented with a catalyst component and preferably also water to serve as a lubricant to facilitate the displacement of the viscous emulsion within the pipeline. loading.

Indeed, the present invention relates more particularly to the use of these products in a hole in which a priming charge and a detonator wire are placed and in which the explosive products (emulsion mixture + gasification reagent) are transferred using a flexible hose.

The present invention relates more particularly to a process in which mixing of the emulsion and porosity reactants is carried out at the site of use of the explosive and more particularly in a hole, in particular a borehole, which the we feeds into an explosive charge using a transfer line from an installation where the emulsion matrix is made and / or stored at a distance from the hole. Typically the hole has a depth of 5 to 30m and a diameter of 5 to 50 cm.

The basic raw material, the emulsion matrix, can be produced on site by a modular plant as described in PCT / FR2014 / 050032 or through a mobile installation, ie trucks carrying materials useful for manufacturing that go to the site of use (mines, quarries or construction site) for the production of explosives.

The transfer and mixing of the 2 components, emulsion on the one hand and gasification reagent on the other hand poses a number of difficulties.

• changer en temps réel, de façon fiable et précise, la densité du produit final en cours de chargement et production en sortie de la conduite de transfert dans le trou en cours de remplissage du trou en continu sans avoir à purger et/ou sortir la conduite de chargement du trou, et, pour ce faire de façon optimale,
• mettre les deux composants en contact l'un avec l'autre et mélanger au niveau d'un mélangeur statique dans le trou en aval de la conduite de transfert déroulée depuis un tambour enrouleur, et
• raccourcir sans difficultés les conduites de transfert lorsque leurs extrémités se dégradent par usure et frottement dans le trou, et
• tout en évitant les risques générer par la présence éventuelle de pièce métallique exposée non protégées dans le trou.

In WO 2015/140462 in the name of the Applicant has described a method and an explosive product production facility comprising the implementation of flexible pipes for loading into a hole reliable, secure and simple to implement and implement on the one hand and that allow to :

• real-time, reliably and accurately change the density of the final product being loaded and outputting the transfer line into the hole being filled continuously without having to purge and / or exit the pipe hole loading, and to do this optimally,
• bringing the two components into contact with each other and mixing at a static mixer in the hole downstream of the transfer line unrolled from a drum drum, and
• to shorten easily the transfer lines when their ends are degraded by wear and friction in the hole, and
• while avoiding the risks generated by the possible presence of unprotected exposed metal part in the hole.

1. 1) on transfère séparément jusqu'à un premier mélangeur, avec une première pompe, un produit visqueux, dénommé matrice, comprenant une émulsion inverse d'une phase aqueuse de comburant et phase huileuse de combustible et avec une deuxième pompe, un produit liquide contenant un composé chimique apte à réagir avec la dite matrice pour en augmenter le caractère explosif par gazéification, dénommé réactif de gazéification, depuis des réservoirs comprenant au moins :
   • un premier réservoir contenant la dite matrice à base de dite émulsion explosive, et
   • un deuxième réservoir contenant ledit réactif de gazéification, et
2. 2) on mélange ledit produit visqueux de dite matrice, et ledit produit liquide de dit réactif de gazéification, dans un mélangeur statique à travers lequel les dite matrice et réactif de gazéification sont transférée en mélange, et
3. 3) on transfère et dépose ledit produit explosif obtenu en sortie du dit premier mélangeur, dans un trou pour explosion, dans ou au-dessus duquel l'extrémité avale du premier mélangeur est disposée, le dit trou étant situé à distance des dits réservoirs, de préférence encore à au moins 20 m, trou, de préférence un trou de forage sensiblement cylindrique, dans lequel de préférence on a précédemment placé une charge d'amorçage d'explosif et un détonateur relié à un fil de détonateur, et

dans lequel :

• à l'étape 1), on commande et contrôle les quantités et/ou débits de dite matrice et de dit réactif de gazéification entrant dans ledit premier mélangeur de manière à produire un dit produit explosif présentant une densité de valeur déterminée en sortie de premier mélangeur à l'étape 2), et
• à l'étape 3), on fait varier la densité du produit explosif obtenu en cours de remplissage selon la quantité de produit explosif déposé et/ou selon la profondeur à laquelle on dépose le produit explosif dans un même trou ou d'un trou à l'autre dans différents trous.

To do this, in WO 2015/140462 the process for producing explosive product in situ comprises the steps of:

1. 1) a viscous product, referred to as a matrix, comprising an inverse emulsion of an aqueous phase of oxidant and an oily phase of fuel and, with a second pump, a liquid product containing a viscous product, referred to as a matrix, is transferred separately to a first mixer; a chemical compound capable of reacting with said matrix to increase its explosive character by gasification, called a gasification reagent, from reservoirs comprising at least:
   • a first reservoir containing said matrix based on said explosive emulsion, and
   • a second tank containing said gasification reagent, and
2. 2) mixing said viscous product of said matrix, and said liquid product of said gasification reagent, in a static mixer through which said matrix and gasification reagent are transferred in a mixture, and
3. 3) transferring and depositing said explosive product obtained at the outlet of said first mixer, into an explosion hole, in or above which the downstream end of the first mixer is disposed, said hole being situated at a distance from said reservoirs, more preferably at least 20 m, hole, preferably a substantially cylindrical borehole, in which an explosive charge and a detonator connected to a detonator wire have previously been placed, and

in which :

• in step 1), the quantities and / or flow rates of said matrix and of said gasification reagent entering said first mixer are controlled and controlled so as to produce an explosive product having a determined value density at the outlet of the first mixer in step 2), and
• in step 3), the density of the explosive product obtained during filling is varied according to the quantity of explosive product deposited and / or the depth at which the explosive product is deposited in the same hole or a hole to be filled. the other in different holes.

according to WO 201540462 said first and second hoses are joined to each other so that said second pipe is disposed entirely within the first pipe forming a set of coaxial pipes, said die being conveyed without contact with the a gasification reagent in the annular space between the two coaxial pipes, said first mixer being disposed inside the first pipe at its downstream end, said second pipe terminating just upstream of said first mixer.

Thus, the gasification reagent is conveyed separately without contact with the matrix until it opens into the static mixer in which an intimate mixture of the two products is produced in order to produce the explosive product at the outlet of the static mixer. end downstream of the first pipe. Said first pipe or outer pipe is secured to said second pipe or inner pipe only at a connecting piece and supply upstream of said drum.

The process according to WO 201540462 It therefore consists in varying the respective proportions of gasification reagent and emulsion matrix entering the mixer to change in real time the density of the product arriving in the hole during a single filling procedure. This is made possible, among other things, by the fact that the reagents R and matrix M are brought into contact just before the mixer and the explosive product deposited in the hole exits directly from said mixer. It is thus possible, according to the invention, to automatically adapt the energy of the explosive to the rock mass in a simple manner by making a single filling of explosive continuously or in the same production cycle, a single sequence of Pumping explosive, a single continuous sequence means here that the dispensing pipe is placed in the hole, then actuates the transfer pump and deposits and spring the pipe after filling the hole to the desired level.

The process according to WO 201540462 allows to modify almost in real time the density of the product and therefore the energy density of the explosive, the latter being inversely proportional to its density, and more particularly, to vary the density of the product allows to have a high density, in the bottom of the hole and a lighter density in the column in height.

A problem of this type of process is to obtain homogeneous or reproducible density mixtures and thus to refine the control of the composition and therefore of the density of the mixture.

Another problem is to be able to obtain an enlarged density range of the mixture product

Another problem is to better control and also to reduce the reaction time between the emulsion matrix and the gasification reagent that occurs in the hole after depositing the mixture therein.

More generally, the object of the present invention is therefore to improve the operating conditions of the in-situ explosive product production method above and in particular also the safety of the process.

In order to do this, it has been found according to the present invention that the technical effect of the static mixer is considerably improved to solve the above problems if the mixture was subjected to a treatment of increasing its viscosity by shearing downstream or preferably upstream of the static mixer preferably by at least doubling the viscosity of the mixture.

1. 1) on transfère séparément jusqu'à un premier mélangeur comprenant de préférence un mélangeur statique, un produit visqueux, dénommé matrice, comprenant une émulsion inverse d'une phase aqueuse de comburant et phase huileuse de combustible et, un produit liquide contenant un composé chimique apte à réagir avec la dite matrice pour en augmenter le caractère explosif par gazéification, dénommé réactif de gazéification, et
2. 2) on mélange ledit produit visqueux de dite matrice, et ledit produit liquide de dit réactif de gazéification, dans ledit premier mélangeur à travers lequel les dite matrice et réactif de gazéification sont transférée en mélange, et
3. 3) on transfère et dépose ledit produit explosif obtenu en sortie du dit premier mélangeur, dans un trou pour explosion, dans ou au-dessus duquel l'extrémité avale du premier mélangeur est disposée,

caractérisé en ce qu'avant l'étape 3), on réalise une augmentation de la viscosité du dit mélange de dite matrice et dit réactif de gazéification par cisaillement au sein d'un tube ou tuyau dans lequel la dite matrice et dit réactif de gazéification sont transférés, en passant le dit mélange dans un dispositif de cisaillement au sein dudit tuyau ou tube.More specifically, the present invention provides a method for in situ production of an explosive product comprising the steps of:

1. 1) is transferred separately to a first mixer preferably comprising a static mixer, a viscous product, called matrix, comprising an inverse emulsion of an aqueous phase of oxidant and oily phase of fuel and a liquid product containing a chemical compound adapted to react with said matrix to increase its explosive character by gasification, called a gasification reagent, and
2. 2) mixing said viscous product of said matrix, and said liquid product of said gasification reagent, in said first mixer through which said matrix and gasification reagent are transferred in a mixture, and
3. 3) transferring and depositing said explosive product obtained at the outlet of said first mixer, into an explosion hole, in or above which the downstream end of the first mixer is arranged,

characterized in that prior to step 3), an increase in the viscosity of said mixture of said matrix and said shear gasification reagent is carried out within a tube or pipe in which said matrix and said gasification reagent are transferred, passing said mixture into a shearing device within said pipe or tube.

The shearing device may be disposed downstream or preferably upstream of said mixer.

More particularly, the shearing device comprises a wall defining a surface of revolution relative to the longitudinal axis XX 'of said pipe or tube forming an internal passage channel of the mixture, a surface of revolution whose cross sectional area of passage of the said mixture gradually decreases from an inlet passage section of the shear device of area S1 to a passage section at the outlet of the shear device of area S2 less than S1 and opening into an area of said tube or pipe more large cross section as the said passage section output.

More particularly, the shearing device comprises a frustoconical wall or frustoconical type called restriction cone forming an internal channel passage of the mixture, the cross section of the mixture passing through said restriction cone gradually decreases passing a circular passage section at the inlet of the restriction cone to a passage section at the outlet of the reduced-size restriction cone, said outlet section being circular or oblong.

• à une première extrémité dans la direction axiale longitudinale, une grande section transversale - c'est à dire dans un plan perpendiculaire à la dite direction axiale longitudinale- la dite grande section transversale étant circulaire, et
• à une deuxième extrémité dans la direction axiale longitudinale, une petite section transversale de plus petite superficie que la grande section transversale, ladite petite section transversale étant circulaire pour une surface tronconique ou respectivement oblongue pour une surface de type tronconique.

Here, the term "frustoconical surface or" frustoconical type "means a surface of revolution defined by a generator constituted by a line inclined with respect to a longitudinal axis and forming a turn around said axis in a fixed inclination for a frustoconical surface or variable inclination for a frustoconical type surface, so as to define:

• at a first end in the longitudinal axial direction, a large cross section - that is to say in a plane perpendicular to said longitudinal axial direction - said large cross section being circular, and
• at a second end in the longitudinal axial direction, a small cross-section of smaller area than the large cross-section, said small cross section being circular for a frustoconical surface or respectively oblong for a frustoconical type surface.

This increase in the viscosity of the mixture ensures a more intimate mixture between the emulsion matrix and the gasification reagent. This makes it possible to obtain a better controlled gasification, namely faster, more homogeneous or more reproducible and finally a yield of the optimized gasification reaction relative to the stoichiometry in terms of quantities of the products used.

More particularly, because of a better yield of the gasification reaction, it is possible to reduce up to 15% or even 25% the amount of gasification reagent to be used comparatively with the same mixer without shearing device.

The gas bubbles are better blocked in the mixture thanks to the higher viscosity (better resistance of the gas bubbles in the matrix), hence the possibility of incorporating more and thus lower density. This is interesting in some applications when one wants to make optimized energy (final objective) and thus this offers more flexibility because the density range is wider. This is also interesting when we want to reduce energy, and therefore density, for special applications such as cutting.

Another advantage is to obtain a faster gasification in the hole before stuffing, which translates concretely on the ground by the possibility of putting the stuffing in the hole over the explosive mixture faster and thus to save time on the cycle of shooting.

Another advantage of the increase in viscosity is to obtain a better accuracy of the load that is to say to better control the removal of the product in terms of quantity (consumption of explosive is better controlled) and accuracy of location (less sag, less loss in cracks).

Another advantage of the viscosity increase is to obtain a better lift of the column of the explosive mixture in the borehole after removal.

More particularly, the viscosity of said mixture is increased by at least a factor of 2.

More particularly, the ratio of the areas of said passage sections of inlet and outlet diameters of the restriction cone is S1 / S2 is at least 2, preferably less than 3.

If the reduction in diameter or S1 / S2 is too high, it limits the flow too much, conversely if S1 / S2 is too low it does not shear enough and does not increase the viscosity enough.

The increase in viscosity is related to a shearing effect created by the diameter reduction. At the entrance of the cone the emulsion droplets which form the matrix are subjected to a uni-axial elongation in the center of the flow and shear resulting from the friction of the mixture on the walls of the device. This divides each drop into a smaller amount of drops, resulting in increased viscosity and increased intimacy between the matrix and the gasification reagent. More gas bubbles are produced. They are better retained by the viscosity increase of the matrix.

Moving from S1 to S2, at a matrix mixing fluid flow rate and equal reagent, the linear velocity of the fluid increases with a velocity ratio equivalent to the quotient of the square of the diameters; thus V2 = V1 x S1 / S2 or else V2 = V1 x D1 ² / D2 ² .

Thus, by passing from D1 = 25 to 35 mm (diameter of a circular section at the cone of restriction cone) to D2 = 5 to 15 mm (diameter of a circular cone outlet section), at a flow of matrix + reagent equal to 50 to 150 kg / min and a density of about 1 to 2 the fluid velocity increases by a factor of about 5 to 15, the value of the viscosity being before shear of 15,000 to 25,000 cps and after shearing 30,000 at 60,000 cps as measured using a Brookfield type viscometer, mobile 7 at 50 rpm.

Thus, passing from D1 = 27 mm to D2 = 10 mm, with a matrix flow rate + reagent equal to 100 kg / min and a density of about 1.30 the fluid velocity increases by a factor of about 7, the value of the viscosity being before shear of 23,000 cps and after shear 45,000 cps as measured using a Brookfield type viscometer, mobile 7 at 50 rpm.

For a flow rate of 100 kg / min, a gasification time of 45 minutes is changed to 25 minutes, ie a decrease of 20 minutes per 100 kg of product at 20 ° C with a pumping rate of 100 kg / min and a density final about 1 +/- 5% with a reduction of the amount of gasification reagent by 20%.

The increase in shear due to the addition of the restriction cone results in the possibility of possibly reducing the length of the mixer compared to previous versions if the shearing device is placed upstream of the mixer.

Even more particularly, mixing is carried out in a first mixer comprising a static mixer placed in a pipe or tube and said shearing device is placed in said pipe or tube just upstream of said static mixer.

Here, in a manner known to those skilled in the art, the term "static mixer" is intended to mean a device containing mechanical elements able to create a modification in the movement of a moving fluid traveling through it creating divisions and rotations of the vortex flow and / or movements allowing mixing without energy input to move said mechanical elements other than that provided by the movement of the fluid. Most often Static mixers consist of a tube containing one or more three-dimensional structures favoring the appearance of divisions and rotations of the flow and / or vortices during the passage of a flow of fluid in the longitudinal direction of the tube.

More particularly, between the shear device and said static mixer is interposed a dispersion device called jet jet in the form of a double transverse crosspiece arranged transversely, axially centered and fixed within said sleeve tube downstream of the outlet orifice of the shearing device for reducing the speed and pressure of the mixing fluid at this level.

This dispersion device aims to mechanically protect the static mixer without affecting the viscosity of the fluid. Thus, for a viscosity increase with diameter reduction mentioned above, it is possible to pass from a pressure of 0.5 × 10 ⁵ Pa at the inlet of the restriction cone to 8 × 10 ⁵ Pa at the outlet. More particularly still, said mixer comprises a plurality of blades or butt fins each having a helical surface, extending in its axial direction (XX ') over a length corresponding preferably to a half-pitch of the corresponding helical curve, said helical surfaces being supported by a same support to which they are preferably fixed juxtaposed in the longitudinal direction of said pipe or tube, said blades of successive helical surfaces being all substantially the same diameter as the inner diameter of the inner surface cylindrical of said pipe or tube and angularly offset in rotation relative to their common virtual axis of helical surface coinciding substantially with a longitudinal axis of said pipe or tube, preferably said successive helical surfaces being shifted by 90 °.

Said blades or helical fins have a twisted or spiral shape and act as a mixer by dividing by two the flux at each fin or blade at their transverse input edge, therefore by a succession of division and rotation of the different currents divided due to the angular offset of each transverse edge output or trailing edge of the blade relative to its input edge preferably at an angle of 90 °, under the effect of the pressure of the flows of matrix and reagent mixed therethrough.

More particularly still, said first mixer comprises a rigid sheath tube which supports said blades or fins which are integral therewith and in which said blades or fins are disposed, the edge of each fin being in contact and secured along its length with the inner wall of said sheath tube, said rigid tube having an outer diameter substantially the same or just sufficiently smaller than the internal diameter of the pipe supplying said first mixer in said mixture and wherein said mixer is disposed.

More particularly, said sheath tube of said mixer comprises lateral perforations. The lateral openings of the sheath have the function of allowing the cleaning of the room after use.

More particularly still, said sheath tube comprises, preferably at its downstream end, a thread on its cylindrical outer wall making it possible to screw it and thus to fix it removably against the inner wall of said first pipe, preferably at its end. downstream.

More particularly still, said first static mixer consisting of said sheath tube and said blades or vanes and said restriction cone which are integral therewith are of material and are made in one and the same piece, preferably plastic.

It can be realized by 3D printing all the elements coming from matter. The previous mixer was made of stainless steel, this one is made of plastic, in particular polyamide reinforced with glass fibers, hence a gain in safety because this mixer is located at the end of the pipe and therefore in contact with explosives and detonators.

More particularly still, in step 1), said matrix is transferred into a first flexible pipe and said gasification reagent is transferred into a second flexible pipe, said first and second flexible pipes being joined together with the other so that said second pipe is disposed entirely inside the first pipe forming a set of coaxial pipes, said die being conveyed without contact with the gasification reagent in the annular space between the two coaxial pipes, said first mixer being disposed within the first pipe at its downstream end, said second pipe terminating just upstream of said shearing device and said first mixer.

• une dite matrice de densité de 1 à 2, notamment 1.2 à 1.6 d'une émulsion de base dite inverse ou « eau dans huile » obtenue par un mélange de (a) une phase continue organique, constituée mélange d'huiles minérales et gasoil, et (b) une phase aqueuse discontinue de divers sels comburants en solution aqueuse à base de particules de nitrate(s) d'ammonium et/ou sodium et/ou calcium ; à un débit de 25 à 300 Kg/min, et
• une solution dit réactif de gazéification de densité de 0.5 à 1.5 à base de nitrite et/ou thiocyanate de sodium, à un débit de 0.1 à 2 L/min ;
• dans un ratio de débit de réactif/ matrice variant de de 0.1 à 2 L/ 100Kg,
• la viscosité dudit mélange avant cisaillement par le dispositif de cisaillement étant de 15 000 à 25 000 cps tel que mesuré avec un viscosimètre Brookfield mobile 7 à 50 tour/min et 30 000 à 60 000 après cisaillement par le dispositif de cisaillement.

More particularly, to produce an explosive product with a density of 0.5 to 1.5, the following is used:

• a said matrix of density of 1 to 2, especially 1.2 to 1.6 of a so-called inverse base emulsion or "water in oil" obtained by a mixture of (a) an organic continuous phase, constituted mixture of mineral oils and gas oil, and (b) a discontinuous aqueous phase of various oxidizing salts in aqueous solution based on ammonium and / or sodium and / or calcium nitrate particles; at a flow rate of 25 to 300 Kg / min, and
• a so-called gaseous reactant solution with a density of 0.5 to 1.5 based on nitrite and / or sodium thiocyanate at a flow rate of 0.1 to 2 L / min;
• in a reagent / matrix flow rate ranging from 0.1 to 2 L / 100Kg,
• the viscosity of said mixture before shearing by the shearing device being from 15,000 to 25,000 cps as measured with a Brookfield mobile viscometer 7 to 50 rpm and 30,000 to 60,000 after shearing by the shearing device.

The present invention also relates to a mixer comprising a shearing device just upstream of a static mixer suitable for being placed in a pipe as defined above and useful in a method according to the invention.

More particularly, said mixer comprises a shearing device attached to a static mixer upstream of said static mixer, said shearing device and said static mixer being arranged within a rigid tube and integral with said rigid tube, said rigid tube being adapted to be placed in a pipe for the implementation of a method according to the invention.

• un dispositif de cisaillement comprenant une paroi interne tronconique ou de type tronconique coaxiale dénommée cône de restriction formant un canal interne de passage du mélange dont la section transversale de passage du mélange à l'intérieur du dit cône de restriction diminue progressivement en passant d'une section de passage circulaire en entrée C1 du cône de restriction jusqu'à une section de passage en sortie C2 du cône de restriction de dimension réduite, la dite section de sortie étant circulaire ou oblongue et débouchant dans une zone du dit tube rigide de plus grande section transversale que la dite section de passage en sortie, et
• un mélangeur statique comprenant une succession de pâles ou ailettes hélicoïdales juxtaposées bout à bout, toutes de même diamètre que le diamètre interne de la paroi interne cylindrique du dit tube, le bord de chaque ailette étant en contact et solidaire sur sa longueur avec la paroi interne dudit tube rigide, et les dites ailettes successives étant décalées angulairement, dans le tube rigide en aval dudit dispositif de cisaillement.

More particularly, said rigid tube forms a sleeve supporting integrally within it:

• a shearing device comprising a frustoconical inner wall or frustoconical type coaxial called restriction cone forming an internal passage passage of the mixture, the cross section of passage of the mixture inside said restriction cone gradually decreases from a circular passage section at the inlet C1 of the restriction cone to a passage section at the outlet C2 of the reduced-size restriction cone, said outlet section being circular or oblong and opening into an area of said larger rigid tube; cross-section than the said section of passage output, and
• a static mixer comprising a succession of helical blades or fins juxtaposed end to end, all of the same diameter as the internal diameter of the cylindrical inner wall of said tube, the edge of each fin being in contact and secured along its length with the inner wall; said rigid tube, and said successive fins being angularly offset, in the rigid tube downstream of said shearing device.

• à l'étape 1), on commande et contrôle les quantités et/ou débits de dite matrice et de dit réactif de gazéification entrant dans ledit premier mélangeur de manière à produire un dit produit explosif présentant une densité de valeur déterminée en sortie de premier mélangeur à l'étape 2), et
• à l'étape 3), on fait varier la densité du produit explosif obtenu en cours de remplissage selon la quantité de produit explosif déposé et/ou selon la profondeur à laquelle on dépose le produit explosif dans un même trou ou d'un trou à l'autre dans différents trous.

More particularly, according to other characteristics:

• in step 1), the quantities and / or flow rates of said matrix and of said gasification reagent entering said first mixer are controlled and controlled so as to produce an explosive product having a determined value density at the outlet of the first mixer in step 2), and
• in step 3), the density of the explosive product obtained during filling is varied according to the quantity of explosive product deposited and / or the depth at which the explosive product is deposited in the same hole or a hole to be filled. the other in different holes.

In the present description, the term "upstream" and "downstream", the position in reference to the flow direction of the fluids in the pipes from the tanks to the first mixer and to the outlet opening into the dispensing hole of the product. explosive at the output of the first mixer.

More particularly, it is ordered to produce specific quantities of explosive products having different density values respectively to deposit successively in a hole being filled, continuously.

Typically, holes 5 to 30 m deep and 5 cm to 20 cm in diameter are formed, and at least two, preferably 4, amounts of explosive product are defined for 4 density values corresponding to mass energies of 2 to 5 MJ. / kg (10 ⁶ J / kg), in particular densities of 0.5 to 1.5.

In practice the amount of explosive product substantially corresponds to the amount of said matrix because the relative amount of reagent is of the order of 0.1 to 2% only relative to the weight of explosive product obtained.

More particularly, at least two, preferably 4, quantities of explosive product are determined and used for decreasing distinct density values, preferably a density exhibiting a said predetermined value between 0.5 and 1.5, more preferably from 0.8 to 1.2, during filling.

In a manner known to those skilled in the art, abacuses allow for a given density value, the respective rates of gasification reagent y and said matrix x vary linearly according to a formula y = ax + b. The values of a and b depend on the composition of said porosity reactants and said matrix. Charts provide graphs of said reactant flow rates in L / min relative to flow values of said matrix in Kg / min. Thus, for a fixed matrix flow rate value, it is sufficient to vary the rate of gasification reagent.

On the other hand, because the viscous product is more difficult to control and it is easier to vary and control the dedication of a liquid fluid, it is advantageous to work with a constant matrix flow and to vary the flow rate of gasification reagent.

More particularly, the respective quantities and flow rates of said matrix and said gasification reagent are controlled and controlled by controlling and controlling valves and / or the speeds of said first and / or second pumps, in an automated manner with the aid of a central control and control unit comprising electronic means controlled by software with a keyboard and / or graphic interface, preferably allows said central unit being supported on a motorized vehicle, preferably said vehicle supporting said first and second tanks and say first and second pump.

Input data of quantities and flow rates of matrix, gasification reagent and explosive product and density can be loaded automatically to the central unit from a USB port or via a WIFI connection to facilitate the procedure and limit the risk of errors.

More particularly, in step 1), said matrix and said gasification reagent are separately transferred from said first and second reservoirs respectively into first pipe and second pipe respectively with a first pump and a second pump, respectively, and control and controlling a constant flow rate of said die by controlling the speed of the first pump with a speed sensor of said first pump, and varying the flow rate of said gasification reagent by controlling the speed of the second pump using a flow meter.

More particularly, said first and second hoses are joined with each other to form a complex set of hoses connected to a take-up drum, and at least partially wound or wound on said take-up drum.

Typically, a reel drum of 30 to 80 cm diameter is used for a pipe 30 to 100m long with external diameters of first pipe 30 to 50mm and internal diameters of 25 to 40mm and external diameters of second pipe 5 to 15 mm with an internal diameter of 3 to 10mm.

• la figure 1A représente une unité mobile de fabrication d'explosifs 1 (abrégée « UMFE ») à savoir un camion 1 transportant le matériel de l'installation selon la présente invention sur son châssis arrière 1a, et le déploiement d'un ensemble de tuyaux coaxiaux 6 déroulés depuis un enrouleur 5 à l'arrière dudit camion, et
• la figure 1B représente une vue en coupe d'un trou de forage 21 réalisé dans un massif rocheux 25 dans lequel est déposé du produit explosif 20, l'extrémité avale ouverte de l'ensemble de tuyaux coaxiaux 6 selon l'invention disposée dans le trou, et
• la figure 2 représente un schéma de montage des matériels de l'installation selon la présente invention en vue de la mise en oeuvre du procédé selon l'invention, et
• la figure 3 représente le détail d'une vue en perspective de l'enrouleur 5, et
• la figure 3A représente une vue en coupe verticale au niveau de la première partie rigide 6₁a du tuyau externe 6₁ de l'ensemble de tuyaux coaxiaux 6, et
• les figures 4A et 4B représentent l'introduction du premier mélangeur statique 7 à l'intérieur et à l'extrémité avale du premier tuyau 6₁ en aval du clapet 6₄ de l'extrémité avale du deuxième tuyau 6₂.
• les figures 5A, 5B et 5C sont des vues de côté (fig.5A), de face à une extrémité (fig.5B) et en coupe longitudinale AA de la figure 5B avec un cône de restriction tronconique (fig.5C).
• les figures 6A et 6B représentent un mélangeur équipé d'un dispositif de dispersion 11 et encore en amont de celui-ci- d'un cône de restriction de type tronconique à section de sortie C2 oblongue.

Other characteristics and advantages of the present invention will emerge more clearly on reading the following description, given in an illustrative and nonlimiting manner, with reference to the appended drawings in which:

• the Figure 1A represents a mobile explosive manufacturing unit 1 (abbreviated "UMFE") namely a truck 1 carrying the equipment of the installation according to the present invention on its rear chassis 1a, and the deployment of a set of coaxial pipes 6 unwound from a retractor 5 at the rear of said truck, and
• the Figure 1B represents a sectional view of a borehole 21 made in a rock mass 25 in which explosive product 20 is deposited, the open downstream end of the set of coaxial pipes 6 according to the invention disposed in the hole, and
• the figure 2 represents a circuit diagram of the equipment of the installation according to the present invention with a view to implementing the method according to the invention, and
• the figure 3 represents the detail of a perspective view of the winder 5, and
• the figure 3A shows a vertical sectional view at the first rigid section 6 ₁ a of the outer pipe 6 ₁ of assembly of coaxial pipes 6, and
• the Figures 4A and 4B represent the introduction of the first static mixer 7 inside and at the downstream end of the first pipe 6 ₁ downstream of the valve 6 ₄ of the downstream end of the second pipe 6 ₂ .
• the FIGS. 5A, 5B and 5C are side views ( 5A ), from front to end ( 5B ) and in longitudinal section AA of the Figure 5B with a frustoconical restriction cone ( 5C ).
• the Figures 6A and 6B represent a mixer equipped with a dispersion device 11 and further upstream thereof a frustoconical type cone of oblong C2 exit section.

detailed description

• un camion 1 supporte sur son châssis arrière la un premier réservoir 1-1 contenant un produit constitué principalement d'une émulsion explosive dénommée « matrice », et
• un deuxième réservoir 1-2 contenant un réactif de gazéification notamment à base de nitrite de sodium et de thiocyanate, et
• un troisième réservoir 1-3 contenant un catalyseur de réaction, à savoir un acide notamment de l'acide acétique et destiné à catalyser la réaction de la matrice avec le réactif de gazéification pour dégager un gaz comme décrit ci-après, et
• un quatrième réservoir d'eau 1-4, et
• un cinquième réservoir de nitrates 1-5.

A facility 1 for producing explosive products 10 in situ, that is to say at the site of use of the explosive, namely, more precisely at a borehole 21 according to the invention, comprises the following equipment arranged as follows:

• a truck 1 supports on its rear chassis the first tank 1-1 containing a product consisting mainly of an explosive emulsion called "matrix", and
• a second tank 1-2 containing a gasification reagent especially based on sodium nitrite and thiocyanate, and
• a third reservoir 1-3 containing a reaction catalyst, namely an acid including acetic acid and intended to catalyze the reaction of the matrix with the gasification reagent to release a gas as described below, and
• a fourth water tank 1-4, and
• a fifth tank of nitrates 1-5.

• une première pompe 2-1 disposée en sortie du premier réservoir 1-1 et destinée à transférer la matrice du premier réservoir 1-1 vers le trou de forage 21 par l'intermédiaire d'un premier circuit comprenant une canalisation de transfert de matrice la puis un ensemble de tuyaux coaxiaux 6 décrit ci-après, et
• une deuxième pompe 2-2 disposée en sortie du deuxième réservoir 1-2 destinée à transférer le réactif de gazéification depuis son deuxième réservoir 1-2 dans un deuxième circuit comprenant une canalisation de transfert de réactif 1b vers l'ensemble de tuyaux coaxiaux 6 tel que décrit ci-après, et
• une troisième pompe 2-3 destinée à transférer le catalyseur depuis son réservoir 1-3 jusque dans le premier réservoir 1-1, et
• une pompe 2-5 et/ou vis d'extraction destinée à transférer le nitrate du cinquième réservoir 1-5 vers ledit premier réservoir 2-1
• une pompe 2-4 destinée à transférer l'eau du quatrième réservoir 1-4 dans un circuit 1c vers le premier circuit la de transfert de la matrice de façon à lubrifier le produit visqueux que constitue la matrice et faciliter son transfert au sein d'un premier tuyau de transfert 6₁ comme décrit ci-après.

The truck 1 also supports on its chassis the following different pumps:

• a first pump 2-1 disposed at the outlet of the first tank 1-1 and intended to transfer the matrix of the first tank 1-1 to the borehole 21 via a first circuit comprising a matrix transfer pipe the then a set of coaxial pipes 6 described below, and
• a second pump 2-2 disposed at the outlet of the second reservoir 1-2 intended to transfer the gasification reagent from its second reservoir 1-2 into a second circuit comprising a reagent transfer line 1b towards the set of coaxial pipes 6 such as described below, and
• a third pump 2-3 for transferring the catalyst from its reservoir 1-3 into the first reservoir 1-1, and
• a pump 2-5 and / or extraction screw for transferring the nitrate of the fifth reservoir 1-5 to said first reservoir 2-1
• a pump 2-4 for transferring water from the fourth reservoir 1-4 in a circuit 1c to the first transfer circuit 1a of the matrix so as to lubricate the viscous product constituted by the matrix and facilitate its transfer within a first transfer pipe 6 _1, as described below.

The junction of the water circuit 1c on the first matrix circuit la is by a piece 1d called "lubrication water injector ring". The function of the water is only the lubrication of the matrix for a reduction of the losses of charges.

The pipe constituting a first matrix transfer circuit connects the first tank 1-1 to a first external flexible pipe 6 ₁ of the pipe assembly 6 wound on a winder 5. And, the second gasification reagent transfer circuit 1b comprises pipes from the second reservoir 1-2 to a second internal gasification reagent transfer pipe 6 ₂ of the pipe assembly 6 wound on the reel 5. The second pipe 6 ₂ is disposed at the inside of the first pipe 6 ₁ and is positioned substantially coaxially inside the pipe 6 ₁ when due to the flow of matrix passing in the annular space between the first pipe 6 ₁ and the second pipe 6 ₂ when one transfers said matrix to the borehole 21.

The truck 1 also supports a static mixer called "second mixer" static 2-6, upstream of the coaxial pipe assembly 6.

• une première vanne V1 en sortie du réservoir 1-1 monté sur la première canalisation la de transfert de matrice, et
• en aval de la première pompe 2-1, une deuxième vanne V2 en sortie du deuxième réservoir 1-2 de transfert de réactif de gazéification coopérant avec le deuxième circuit 1b de transfert de réactif de gazéification en amont de la deuxième pompe 2-2, et

• une vanne d'isolement 1-2a en amont du deuxième réservoir de réactif de gazéification 1-2, et
• une troisième vanne V3, vanne trois voies permettant d'alimenter une canalisation de dérivation 1b-1 du deuxième circuit 1b de réactif de gazéification connecté à la première canalisation de transfert de matrice la en aval de la première vanne V1 mais en amont dudit deuxième mélangeur statique 2-6.

The truck 1 also supports on its rear chassis the valves comprising:

• a first valve V1 at the outlet of the tank 1-1 mounted on the first channel of transfer matrix, and
• downstream of the first pump 2-1, a second valve V2 at the outlet of the second reservoir 1-2 of transfer of gasification reagent cooperating with the second gasification reagent transfer circuit 1b upstream of the second pump 2-2, and

• an isolation valve 1-2a upstream of the second gasification reagent tank 1-2, and
• a third valve V3, a three-way valve for supplying a bypass line 1b-1 of the second gasification reagent circuit 1b connected to the first matrix transfer line 1a downstream of the first valve V1 but upstream of said second mixer static 2-6.

The truck 1 also supports on its rear chassis the central control unit 9 comprising a keyboard and / or a graphical interface, cooperating with software capable of controlling the actuation of said pumps and said valves.

Downstream of the third valve V3, the gasification reagent transfer circuit 1b joins the first matrix transfer circuit 1a downstream of the second mixer 2-6 at a connecting part called the first connection piece 3 which ensures the connection between the first pipe 1a and the second pipe 1b just upstream of the set of coaxial pipes 6 wound on the winder 5, so that the flow of gasification reagent is transferred into the second inner pipe 6 ₂ and the flow of matrix from the first circuit is transferred inside the first pipe 6 ₁ and outside the second pipe 6 ₂ in the annular space between the inner wall of the first pipe 6 ₁ and the second pipe 6 ₂ as described below.

The valve V3 makes it possible, by forcing the circulation of the gasification reagent to the bypass 1b-1, to obtain a first operating mode of the installation according to a traditional method in which the gasification reagent and the matrix are mixed within the mixer. 2-6 upstream of the transfer pipe assembly 6 to the borehole 21. In this conventional embodiment, the explosive product produced within the mixer 2-6 is conveyed over a long distance, i.e. all along a long pipe joining the borehole 21.

• en aval de la deuxième pompe 2-2, un débitmètre 2-2a, et
• un capteur de vitesse 2-1a permet de connaître la quantité de produit débité par la pompe.

The chassis 1 of the truck 1 also supports a 2-5 filter upstream of the second pump 2-2 and downstream of the second reservoir 1-2. In addition, the chassis also supports it:

• downstream of the second pump 2-2, a flow meter 2-2a, and
• a speed sensor 2-1a makes it possible to know the quantity of product delivered by the pump.

Downstream of the first pump 2-1, are also mounted on the first circuit 1-a different sensors namely, a matrix fluid pressure sensor 1a-1, a temperature sensor 1a-2, and a detection sensor no flow rate of matrix flow 1a-3.

A second gasification reagent transfer pipe is disposed within a first die transfer pipe 6-1, to form a pipe assembly 6 according to the following arrangement.

The two independent matrix transfer pipes 1a and gasification reagent transfer 1b meet at a first connection piece 3 with rotary joint connections.

The said connecting piece is also used for the lateral feeding of the internal gasification reagent pipe from said second transfer circuit and upstream of said first connecting piece, said first and second circuits are separated and extend from said first and second tanks in different directions and said first piece provides the coaxial connection of the two first and second pipes downstream thereof, the two flows of said matrix and said reagent remaining however separated to the first mixer.

More particularly, the attachment of the upstream ends of said first and second pipes to said first and second ports the said first connection piece is made via two connectors with rotating joints 4 ₁ each allowing separately the rotation on itself with respect to said longitudinal axis (XX ') of the upstream ends of said first and second respectively pipes, said first connecting piece and said joints with rotating joints being arranged upstream of said winding drum so that said first and second outlet orifices are arranged in the axis of rotation of said drum. This feature is particularly advantageous because it avoids twisting of said first and second pipes during winding and unwinding of said pipes on said reel when the upstream uncoiled portions of said pipes are rotated on themselves relative to said axis of rotation said drum in a differentiated manner.

The first connecting piece 3 is disposed just upstream of a drum winder 5 supported by a structure or beam 5a. On the winding drum 5, is wound a flexible downstream portion 6 _1b of the first pipe 6 ₁ connected to an upstream rigid portion 6 ₁ by a removable collar 6 ₁ c.

The upstream rigid portion 6 _1a of the first pipe 6 ₁ integral with both of the first connecting piece 3 via the first rotary joint connection 4 ₁ and also integral with the winding drum 5 is thus rotated with the winding drum 5 around it of the common axis of rotation XX 'of the winding drum 5 and said rotary joints 4 ₁ and the connecting piece 3.

The rigid portion 6 ₁ has different bends, so that its upstream portion is disposed in the axial direction XX 'of the first connecting piece 3 while its downstream portion at the collar 6 ₁ c is arranged in a tangential direction of a cylindrical portion 5 ₁ of the winding drum 5 on which can be wound the second flexible part 6 _1b of the first pipe 6 ₁ upon actuation of rotating the winding drum 5.

The second pipe 6 ₂ disposed inside the first pipe 6 ₁ but has two flexible parts 6 ₂ a and 6 ₂ b interconnected by a double union connection 6 ₃ . Fitting dual-law status 6 ₃ is disposed just downstream of the collar 6 ₁ c so that when opening and / or removing the collar 6 ₁ c to separate the two parts of the first pipe 6 and 6 _{1a 1b,} we can extract the second pipe 6 ₂ and uncouple the two parts 6 and 6 _{2 2} a second pipe 6 b ₂ and easily shorten as necessary the downstream portion b _{2 June} when one has previously been led to shorten the worn downstream end of the flexible portion 6 _1b of the first pipe 6 _1, as described below.

The downstream end of the second pipe 6 ₂ comprises an anti-return valve 6 ₄ , for example of the type sold by the company Swagelok. The valve 6 ₄ is located as close technically as possible to the upstream end of a first static mixer 7 disposed at the downstream end of the first pipe 6 ₁ . The valve 6 ₄ opens under the reactive pressure gasification browsing the pipe 6 ₂ When the pump 2 ₂ operates; and the valve 6 ₄ closes when the second pump 2-2 stops and the gasification reagent flow pressure decreases. The valve 6 ₄ is connected to the downstream end of the inner pipe 6 ₂ . This valve is important to allow the reliable and accurate control of the variation in real time during filling of the hole of the density of the explosive product obtained by mixing said matrix and said gasification reagent.

For the flexible portion 6 _1b of the first pipe 6 _1, a flexible thermoplastic may be used in outer diameter 42 mm and internal diameter of 32 mm, 30 to 100 m long. For the second pipe 6 ₂ , thermoplastic pipes of external diameter of 13.2 mm and internal diameter of 8.3 mm will be used.

On the figures 5 and 6 there is shown an original static mixer 7 according to the present invention. Said first mixer 7 consists of a cylindrical sheath tube 7b which extends over a length of 0.25 to 1m and of external diameter just below inner diameter of the first pipe 6 ₁ is for example about 32 mm and inner diameter about 27 mm. This sheath tube comprises a plurality of spaced lateral orifices 7c to facilitate internal cleaning. In one embodiment, said tube comprises at its longitudinal ends upstream and downstream transverse bars 7d which facilitates handling making it capable of being apprehended by a hook as necessary to put it in place or remove it. Advantageously, its outer surface comprises a thread 7e to allow attachment against the inner surface of the pipe 6 ₁ .

The sleeve tube 7b contains and supports 4 to 8 fins or twisted blades with helical surface 7a juxtaposed in the direction X ₁ X ₁ 'of the tube 7b, the helical longitudinal edge of each fin being fixed to the inner wall of said tube, said fins therefore all having the same diameter corresponding to the internal diameter of said tube.

The fins 7a are juxtaposed against each other in the longitudinal direction X ₁ X ₁ ', but the different portions of helical surfaces are not continuous helically, that is to say that the trailing edge of each fin is angularly offset from the transverse input edge of said fin and the transverse input edge of the next fin. More particularly, the successive fins are angularly offset so as to optimize the performance of said mixer, in particular staggered at 90 ° successively with respect to the axis X ₁ X ₁ '. Specifically, the helical elements have a diameter of substantially 30mm, a helical surface thickness of about 2mm, a length of about 50mm and an angular offset of about 90 °, the total length of the mixer being about 400mm.

The flow of gasification reagent leaving the valve 6 ₄ and the flow of matrix arriving at the valve 6 ₄ outside thereof, can begin to mix in the pipe 6 and then within the restriction cone 10 where they undergo an increase in viscosity before mixing more intimately at the fins 7a.

Preferably, the various successive helical elements 7a are successively in reverse direction. The flow of material through the static mixer in the longitudinal direction X ₁ X ₁ ', becomes laminar and is divided into partial currents by a first helical element 7a, then redivated to the passage of a following helical element 7a and so on which causes by the action of the blades or blades a rotation of the mixture product on itself. In principle, the helical elements 7a are not themselves in relative movement with respect to the fluid mixture and in any event, no source of power is required other than that provided by said pumps to overcome the pressure drop. induced by the baffles formed by the successions of said helical elements 7a.

2 embodiments of the shear device or restriction cone 10 are shown on the Figures 5C and respectively 6A.

• un orifice d'entrée C1 circulaire de diamètre égale au diamètre interne du fourreau soit environ 27mm,
• un orifice de sortie C2 circulaire de diamètre réduite de 6-18mm, de préférence 10-12mm.

On the Figure 5C , the restriction cone is particularly suitable and preferred in the case of a matrix as described below with fine ammonium nitrate particles that is to say less than 1.5 mm in size with a pumping rate of less than 100 kg / min. The wall of the restriction cone is a frustoconical wall forming an internal passage channel of the fluid with:

• a circular inlet C1 of diameter equal to the inside diameter of the sleeve is about 27mm,
• a circular exit orifice C2 of reduced diameter of 6-18mm, preferably 10-12mm.

• un orifice d'entrée C1 circulaire de diamètre égale au diamètre interne du fourreau soit environ 27mm
• Orifice de sortie oblongue de longueur D2 dans une première direction perpendiculaire à l'axe XX', D2 =15-25mm et de longueur d2 dans une deuxième direction perpendiculaire à l'axe XX', d2= 5-15mm.

On the Figure 6A , the restriction cone is particularly suitable and preferred in the case of a matrix as described below with larger ammonium nitrate particles that is to say of size from 1.5 to 3 mm and the pumping rate greater than 100 kg / min. The wall of the restriction cone is a frustoconical wall with:

• a circular inlet opening C1 of diameter equal to the internal diameter of the sheath is approximately 27mm
• Oblong outlet orifice of length D2 in a first direction perpendicular to the axis XX ', D2 = 15-25mm and of length d2 in a second direction perpendicular to the axis XX', d2 = 5-15mm.

In the embodiment shown, the oblong shape is circumscribed to two adjacent circles of diameter d2, namely D2 = 20 mm and d2 = 10 mm.

The axial length of the cone is 20-40m.

In the frustoconical embodiment of the Figure 5C , the slope of the frustoconical wall is constant from about 10 to 60 °, here about for an axial length (distance between C1 and C2) of about 20 mm.

In the frustoconical embodiment of the Figure 6A , the slope of the wall of the restriction cone is variable from 5 ° to 50, here from 10 ° to 30 ° (10 ° in the lateral circular part, 30 ° in the median right part) for an axial length of about 20mm.

The distance L2 from cone 10 to disperser 11 is 35 mm and the distance from disperser 11 to the first helical blade is about 10 mm.

On the Figures 5C and 6A , a sheath tube of length = 250mm containing only 4 blades 7a 40mm in length is sufficient because of the increase in viscosity.

In both cases, said circular or oblong outlet section opens into an area of said rigid tube of greater cross section than said outlet passage section.

A dispersing device referred to as a jet breeze 11 is in the form of a transverse transverse double crossbeam, axially centered and fixed within said barrel tube downstream of the outlet orifice (C2) of the shear device which reduces the speed and pressure of the fluid at this level. This dispersion device aims to mechanically protect the static mixer without affecting the viscosity of the fluid. Thus, for a viscosity increase with diameter reduction mentioned above, it is possible to pass from a pressure of 0.5 × 10 ⁵ Pa at the inlet of the restriction cone to 8 × 10 ⁵ Pa at the outlet at the orifice C2, thus at the center of the tube 7b.The flow of the mixing fluid abuts on the center of the jet breeze where the two ties meet at 90 ° which reduces the pressure of the mixing fluid where it is the strongest.

Fixing the mixer 7 by screwing at its thread 7e against the inner wall 6 ₁ e of the downstream end of the first pipe 6 ₁ has the essential function of holding the static mixer 7 within the downstream end of the first pipe 6 ₁ . The unscrewing makes it possible to remove the first mixer 7 from the downstream end of the first pipe 6 ₁ and thus to be able to cut the downstream end of the pipe 6 ₁ when it is damaged after a certain number of uses because the surface external end of the downstream end of the pipe 6 ₁ in contact with the walls of the drill holes 21 formed of rocky 25 tend to damage the downstream end of the pipe 6 ₁ during the operation.

The fixing of each helical fin is performed at their peripheral edges on the inner surface of the sheath 7b.

Upstream of the succession of helical fins 7a is an element called disperser or jetbreaker 11, optional, interposed between said fins 7a of the static mixer and a shearing device consisting of a restriction cone 10 according to the present invention. , the disperser 11 and the restriction cone 10 being also integral with and supported by said sheath tube 7b.

In fact, according to an original feature of the present invention, the mixer 7 comprising the sheath tube, the helical fins 7a and the disperser 11 and restriction cone 10 contained and supported by the sheath tube are made of material and constitute a single piece of material. one piece manufactured by 3D printing of glass fiber reinforced polyamide. This one-piece manufacturing is advantageous because this piece is thus more solid with greater ease of disassembly and maintenance.

Advantageously, a method according to the invention is used in which the density of the explosive product produced continuously is varied during the filling of a borehole 21 in a single pass, that is to say, without having to raise the pipe 6 during filling, as described below.

• huile minérale et/ou de vidange de moteur : 6,5 %,
• gasoil : environ 1%,
• agents tensioactifs non ioniques: 1%,
• nitrates d'ammonium et/ou de calcium et/ou sodium : environ 75%,
• eau : environ 15 à 20 %.

The emulsion consists of the following components:

• mineral oil and / or engine oil drain: 6.5%,
• diesel: about 1%,
• nonionic surfactants: 1%,
• ammonium and / or calcium and / or sodium nitrates: approximately 75%,
• water: about 15 to 20%.

To the above emulsion thus obtained, ammonium and / or calcium nitrates are added in a proportion of 15 to 35% and a catalyst for example of acetic acid in a proportion of 0.5 to 2%. to which one can also add aluminum (in the form of powder of particle size between about 100μm and 2mm) in a content of 1 to 10% by weight also. This matrix is thus obtained according to the present description within the first reservoir 1-1.

• huile minérale et/ou de vidange moteur : 4.55%,
• gasoil : 0.7%
• agents tensio-actif : 0.7%
• nitrate d'ammonium en solution : 52.5%
• eau : 11.55%
• nitrate d'ammonium sous forme de particules solides : 30%

An example of a matrix formulation is therefore:

• mineral oil and / or engine oil: 4.55%,
• Gas oil: 0.7%
• surfactants: 0.7%
• ammonium nitrate solution: 52.5%
• water: 11.55%
• ammonium nitrate in the form of solid particles: 30%

To this matrix is added according to the process of the present invention, a gasification reagent which is here in particular an aqueous solution of about 20% of sodium nitrite and 80% of water may include catalysts such as sodium thiocyanate , sodium formate, zinc nitrate and / or calcium nitrate.

The density of the basic emulsion (not supplemented) described above is for example about 1.4 to 1.6 and the density of the supplemented emulsion defining said matrix as described above, before mixing with the gasification reagent is 0.8 to 1.3.

The density of the gasification reaction mixture product within said first mixer is from 1.25 to 1.45 according to the respective proportions of quantities and / or flow rates of said matrix and said gasification reagent and the density of the explosive product after gasification. is from 0.8 to 1.2.

The average energy of an explosive product of density 1.2 is 3.7 MJ / kg, ie 4.44 MJ / L. Thus, for an explosive product with a density of 0.5 to 1.5, the explosive energy will be 1.85 to 5.55 MJ / L.

• pour d = 0,8, Y = 0,0117X + 0,002, et
• pour d = 0,9, Y = 0,0085X + 0,0012, et
• pour d = 1, Y = 0,006X, et
• pour d = 1,1, Y = 0,0039X + 0,0019, et
• pour d = 1,2, Y = 0,0021X.

For a Y gasification reagent rate in L / min (product / liquid) as a function of a matrix flow X in kg / min of viscous product, the relation Y = aX + b is given by charts with values of a and b different according to the density values d of the explosive product obtained after gasification resulting from the reaction between said matrix and the gasification reagent by intimate mixing within the static mixer. Thus, the different values of a and b are for example here:

• for d = 0.8, Y = 0.0117X + 0.002, and
• for d = 0.9, Y = 0.0085X + 0.0012, and
• for d = 1, Y = 0.006X, and
• for d = 1.1, Y = 0.0039X + 0.0019, and
• for d = 1.2, Y = 0.0021X.

There is therefore a linear relationship between X and Y depending on the final density of the explosive product resulting from the reaction by intimate mixing of the two products.

The automated control and control unit 9 makes it possible to control the proportional valves V1 and V2 regulating the flows of matrix and gasification reagent, and the actuation and speed of the motors of the pumps 2-1 and 2-2. The flow rates X and Y are provided by calibrating the pump 2-2 speed sensor 2-2 for the values of X (kg / min) and by the flow meter 2-2a for the gasification reagent Y flow (L / 2). min).

In practice, since the gasification reagent R ₂ is in a smaller quantity and in liquid form, it is easier to control the flow rate so that it operates with a constant matrix flow rate X = 125 kg / min.

Thus, the operator driving the selected plant will select the desired explosive product densities as well as the corresponding amounts for each density based on his needs analysis in the relevant borehole given the surrounding rocky environment. the hole to be felled. X being constant, the flow rate of gasification reagent is determined automatically from the chart according to the desired density. In practice, for each blast hole 21, the operator will choose up to four different densities called d1, d2, d3 and d4. The densities d1 to d4 of explosive products to be produced and the corresponding quantities are entered at the level of the central unit 9 via a touch-sensitive keyboard 9a appearing on the screen of the graphic interface 9b. The operator can then start a pumping cycle.

• on charge 20 kg de produits explosifs de densité 1,2 avec par exemple un débit de réactif de gazéification de 0,21 L/min, et
• on change de consigne et on donne l'ordre de charger 25 kg de produit explosif 20 de densité 1 qui viendront donc se déposer par-dessus les 20 kg de produits explosifs de densité 1,2 précédemment déposés au fond du trou depuis l'extrémité avale du tuyau 6_1, en mettant en oeuvre par exemple un débit de réactif de gazéification de 0,60 L/min ; puis
• on charge 50 kg de produits explosifs à densité de 0,9, par-dessus le produit explosif précédemment déposé, en mettant en oeuvre par exemple un débit de réactif de gazéification de 0,80 L/min, puis
• on charge au sommet de la colonne, 30 kg de produit explosif 10 de densité d = 0,8, obtenu en transférant par exemple un débit de réactif de gazéification de 0,90 L/min.

The centralized and automated control unit 9 then automatically controls the regulation of the flow and therefore the flow rate of reagent R2 for a given matrix flow M. Thus, for example, the production cycle of a cylindrical hole 20 m deep and 115 mm in diameter will be performed as follows for a supplemented matrix having a density, in the example below, of about 1.3 :

• 20 kg of 1.2 density explosive products are loaded with, for example, a gasification reagent flow rate of 0.21 l / min, and
• the set point is changed and the order is given to load 25 kg of explosive product 20 of density 1 which will then be deposited on top of the 20 kg of 1.2 density explosives previously deposited at the bottom of the hole from the end. downstream of the pipe 6 _{1, using} for example a flow of gasification reagent of 0.60 L / min; then
• 50 kg of explosive products with a density of 0.9 are loaded on top of the previously deposited explosive product, for example using a gasification reagent flow rate of 0.80 l / min, and then
• at the top of the column, 30 kg of explosive product 10 of density d = 0.8, obtained by transferring, for example, a flow of gasification reagent of 0.90 L / min.

The automated central unit 9 thus makes it possible to control and control the gasification reagent flow rate values as described above, simply by adjusting the speed of the hydraulic motor of the second pump 2-2 transferring the gasification reagent, and by maintaining a substantially constant flow rate of 125 kg / min of said matrix. Such control and flow regulation of the gasification reagent makes it possible to vary, almost in real time, the product density value obtained at the outlet of the first static mixer 7 and discharged directly into the borehole, because of the automation of the control and regulation of the flow of gasification reagent by the central unit 9.

More particularly, said explosive product obtained at the outlet of said first mixer is transferred to and deposited in an explosion hole 21, in or above which the downstream end of the first mixer is disposed, said hole being situated at a distance from said tanks, of at least 20 m, hole, preferably a substantially cylindrical borehole, in which an explosive ignition charge 22 and a detonator 23 connected to a detonator wire 24 have previously been placed.

Comparative tests of the same mixer 7 described above with and without restriction cone 10 have been carried out which demonstrate an increase in viscosity and especially amounts of gasification reagents and gasification reactions in the borehole (before stuffing ) as explained in the table below. criteria Unit Previous situation New mixer Matrix pumping rate + NA (* 1) Kg / min 100 100 Content of gasification reagent in the mixture % 0.73 0.73 Initial density of the mixture 1.36 1.36 Viscosity of the mixture before passing through the mixer cps 23,000 23,000 Restrictor cone in the mixer No Cone D1 = 27 mm to D2 = 10 mm Viscosity after passage in the mixer cps 23,000 45,000 Final measured density of the explosive column (* 2) 1.07 1.02 Efficiency of the gasification reaction (* 3) % 88 95 Time required to obtain the final density of the column equal to 1.07 min 20 10 * 1 =: NA = Ammonium nitrate
* 2: Final measured density of a 10 m high explosive column (100 kg in a 115 mm diameter borehole) versus the reagent content (0.73%)
* 3: The theoretical final density of the explosive column for a reaction efficiency of 100% is 0.95.

Claims (15)

A method for in situ production of explosive product (10) comprising the steps of: 1) is separately transferred to a first mixer (7) preferably comprising a static mixer, a viscous product, called matrix, comprising an inverse emulsion of an aqueous oxidant phase and oily phase of fuel and a liquid product containing a chemical compound capable of reacting with said matrix to increase its explosive character by gasification, called a gasification reagent, and 2) mixing said viscous product of said matrix, and said liquid product of said gasification reagent, in said first mixer (7) through which said matrix and gasification reagent are transferred in a mixture, and 3) transferring and depositing said explosive product obtained at the outlet of said first mixer, in an explosion hole (21), in or above which the downstream end of the first mixer is arranged, characterized in that before step 3), an increase in the viscosity of said mixture of said matrix and said shear gasification reagent is achieved within a tube or pipe (6, 7b) in which said matrix and said gasification reagent is transferred, passing said mixture into a shearing device (10) within said pipe or tube (6,7). Process according to Claim 1, characterized in that the shearing device (10) comprises a wall defining a surface of revolution with respect to the longitudinal axis of said pipe or tube forming an internal passage channel for the mixture, a surface of revolution whose area cross section of the passage of the mixing progressively decreases from an inlet passage section (C1) of the surface shear device S1 to an outlet section (C2) of the shear device of area S2 smaller than S1 and opening into an area of said tube or pipe of greater cross section than said passage section output. Process according to Claim 1 or 2, characterized in that the shearing device (10) comprises a frustoconical or frustoconical type wall known as a restriction cone (10) forming an internal channel for the passage of the mixture, the cross section of which passes from the mixture to the inside of said restriction cone gradually decreases from a circular passage section at the inlet (C1) of the restriction cone to a passage section at the outlet (C2) of the restricted restriction cone, the said outlet section being circular or oblong. Process according to one of Claims 1 to 3, characterized in that the viscosity of said mixture is increased by at least a factor of 2. Method according to one of claims 2 to 4 characterized in that the ratio of the areas of said inlet passage (cl) and outlet (c2) sections of the restriction cone is S1 / S2 is at least 2 of preferably less than 3. Process according to one of Claims 1 to 5, characterized in that the mixing is carried out in a said first mixer (7) comprising a static mixer (7a) placed in a pipe (6) or tube (7b) and placed in the said shearing device (10) in said pipe or tube just upstream of said static mixer. Process according to Claim 6, characterized in that between the shearing device (10) and the static mixer (7a) is inserted a dispersion device called a jet breeze (11) forming a transversally arranged double transverse crosspiece. axially centered and fixed within said barrel tube downstream of the outlet (C2) of the shear device to reduce the velocity and pressure of the fluid at this level. Method according to one of claims 1 to 7, characterized in that said first mixer comprises a plurality of blades or vanes (7a) end to end each having a helical surface, extending in its axial direction (XX ') on a length corresponding preferably to a half-pitch of the corresponding helical curve, said helical surfaces being supported by a same support (7b) to which they are preferably fixed so juxtaposed in the longitudinal direction of said pipe or tube, said pale successive helical surfaces being all substantially of the same diameter as the internal diameter of the cylindrical inner surface of said pipe or tube and angularly offset in rotation with respect to their common virtual axis of helical surface coinciding substantially with a longitudinal axis of said pipe or tube (7b), preferably said successive helical surfaces being offset by e 90 °. Method according to one of claims 1 to 8, characterized in that said first mixer (7) comprises a rigid sleeve tube (7b) which support said blades or fins (7a) which are integral therewith and within which said blades or fins are arranged, the edge of each fin being in contact and secured along its length with the inner wall of said sleeve tube, said rigid sleeve tube (7b) having a substantially identical outer diameter or just sufficiently smaller than the internal diameter of the pipe (6.6-1) feeding said first mixer in said mixture and wherein said first mixer is arranged. Method according to claim 9, characterized in that said sheath tube comprises lateral perforations (7c). Method according to one of claims 9 to 10, characterized in that said first mixer consisting of said sleeve tube (7b) and said blades or fins (7a) and said restriction cone (10) which are integral therewith are realized in one and the same piece, preferably made of plastic. Method according to one of claims 1 to 11, characterized in that in step 1), said matrix is transferred into a first flexible pipe (6 ₁ ) and said gasification reagent is transferred into a second flexible pipe (6 ₂ ), said first and second hoses being joined to each other so that said second pipe (6 ₂ ) is disposed entirely inside the first pipe (6 ₁ ) forming an assembly ( 6) of coaxial pipes, said matrix being conveyed without contact with the gasification reagent in the annular space between the two coaxial pipes, said first mixer being disposed inside the first pipe at its downstream end, said second pipe being terminating just upstream of said shearing device (10) and said first mixer (7). Process according to one of Claims 1 to 12, characterized in that , to produce an explosive product with a density of 0.5 to 1.5, the following is used: a so-called density matrix of 1 to 2 of a so-called inverse or "water-in-oil" base emulsion obtained by a mixture of (a) an organic continuous phase, constituted mixture of mineral oils and gas oil, and (b) a discontinuous aqueous phase of various oxidizing salts in aqueous solution based on ammonium nitrate particles and / or sodium and / or calcium; at a flow rate of 25 to 300 Kg / min, and a so-called gaseous reactive solution with a density of 0.5 to 1.5 based on nitrite and / or sodium thiocyanate, at a flow rate of 0.1 to 2 L / min; in a reagent / matrix flow ratio varying from 0.1 to 2 L / 100 kg, the viscosity of said mixture before shear by the shearing device being from 15,000 to 25,000 cps as measured with a Brookfield mobile viscometer 7 at 50 rpm and 30,000 to 60,000 after shearing by the shearing device. Mixer (7) comprising a shearing device (10) fixed to a static mixer (7a) upstream of said static mixer (7a), said shearing device and said static mixer being arranged within a rigid tube and secured said rigid tube, said rigid tube being adapted to be placed in a pipe (6) for carrying out a method according to one of claims 1 to 13. Mixer according to Claim 14, characterized in that the said rigid tube (7b) forms a sheath integrally supporting within it: a shearing device (10) comprising a frustoconical or frustoconical inner type wall called a restriction cone (10) forming an internal channel for passing the mixture, the cross-section of the mixture of which passes inside said restriction cone; progressively decreases by passing from a circular passage section at entry (C1) of the restriction cone to a passage section at the outlet (C2) of the restriction cone of reduced dimension, the said output section being circular or oblong and opening into an area of said rigid tube of greater cross-section than said outlet passage section, and - A static mixer comprising a succession of blades or helical fins (7a) juxtaposed end to end, all the same diameter as the internal diameter of the cylindrical inner wall of said tube, the edge of each fin being in contact and secured along its length with the inner wall of said rigid tube, and said successive fins being angularly offset, in the rigid tube (7b) downstream of said shearing device.

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