FR2770419A1 - Nozzle which whips to and fro under pressure to agitate the surrounding fluid during injection - Google Patents

Abstract

Injecting a fluid into a fluid medium for mechanical agitation. An extended flexible nozzle (11) in the vessel is fixed at one end (12) to a source (15) of fluid under pressure, and free at the discharge end (13). The fluid under pressure produces whipping movements of the nozzle to mix the medium and random movements of the discharge end to direct a fluid jet in various directions The pressure of the fluid fed to the nozzle is varied or the fluid is intermittent. The fluid is gas to ensure the fluidization of a powdered material. The nozzle is placed upstream of a sieve and supplied with gas to ensure that the material is agitated and the sieve vibrated whilst fluidizing the material and blowing it in the direction of the sieve. Device for carrying out the process and installation containing such a device, with the nozzle upstream or downstream of the sieve (for agitation or unblocking).

Description

 The present invention relates to the technical field of injecting a fluid into a medium with a substantially fluid behavior. The invention also relates to the field of mechanical agitation with the additional action of unclogging such a medium. For the purposes of the invention, the term “medium with a substantially fluid behavior” should be understood to mean a medium such as for example solid matter in powder form, a liquid containing or not particles in suspension, a more or less viscous liquid, sludge or the like, without this list being considered exhaustive but also the means of confinement and / or circulation of such a medium.

 In a preferred application, the invention relates more particularly to fluidization and mechanical agitation of a medium involving pulverulent material.

 It is known practice to fluidize pulverulent material in order to ensure its transport within processing, storage, packaging or similar installations. Such fluidization generally involves the injection of a pressurized gas into the pulverulent material, so as to give it a substantially fluid behavior. The injection of the gas under pressure is carried out by means of rigid nozzles or nozzles formed in the walls of the transport, treatment, storage or similar enclosure.

 This injection method is generally satisfactory and makes it possible to obtain good fluidization of a medium formed of pulverulent material. However, depending on the nature of the material or powder to be transported, as well as on the nature of the treatment undergone by this powder, it is possible that a solidification or agglomeration may occur which could cause the enclosure ensuring the transport to be closed. , containment or storage of powdery material. When such agglomeration or solidification occurs, it is necessary to unclog the enclosure by destruction and / or extraction of the plug formed.

 It appeared that the known means for injecting the fluidizing gas do not make it possible to prevent the appearance and the formation of such plugs causing a malfunction and requiring a shutdown of the installation to carry out the unclogging operation. However, any shutdown of the installation results in a financial operating loss. In addition, the uncorking operation requires the implementation of material and human resources which represent a relatively large expense.

 The need therefore appears to have a method and a device which make it possible to ensure the fluidization of a medium formed of pulverulent material while preventing the appearance of agglomeration of this material.

 A substantially similar problem arises, for example, for the treatment of a liquid or more generally fluid medium, in which it may be necessary to inject a treatment fluid and to proceed jointly with mixing or mixing of the medium to ensure better distribution of the treatment fluid and to avoid, if necessary, agglomeration of any particles in suspension in the medium.

 An object of the invention is therefore to propose a new method for ensuring, on the one hand, an injection of a fluid within a medium with substantially fluid behavior and, on the other hand, mechanical agitation of this medium. contained in a transport, storage, treatment or similar enclosure, in order to avoid clogging by the appearance of deposits or agglomerations inside this enclosure and to allow good distribution of the injected fluid.

 Another objective of the invention is to propose a method and a device the implementation and realization of which are simple and inexpensive.

In order to achieve these objectives, the invention relates to a method for injecting a fluid into a medium with a substantially fluid behavior for mechanical agitation and / or for unclogging this medium contained in a transport enclosure, storage, processing or the like. According to the invention, the method consists in
- have at least one elongated flexible nozzle in the enclosure,
immobilized at a first terminal part which is connected to a
source of pressurized fluid, free at a second end portion
opening,
- supply the nozzle with pressurized fluid to drive by reaction,
on the one hand, whip movements of the nozzle which agitate the medium
and, on the other hand, random displacements of the terminal part which
directs a jet of fluid in the medium, in various directions.

The invention also relates to a device for injecting a fluid into a medium with a substantially fluid behavior and for mechanically agitating this medium contained in a transport, storage, treatment or similar enclosure, comprising at least one flexible elongated nozzle which is arranged inside the cavity and which has
- a fixed terminal part connected to a supply pipe
in pressurized fluid,
- a free and opening terminal part,
The invention also relates to an installation for implementing the method in a transport, storage, processing or similar enclosure which contains a medium with a substantially fluid behavior, comprising
- a source of pressurized fluid,
- And at least one injection and stirring device arranged in
the enclosure and connected to the fluid source.

 The problem of the agglomeration of the pulverulent material also arises in a particularly acute manner in the so-called sieving installations which have a sieve whose meshes ensure a particle size sorting of the pulverulent material and at the level of which such agglomerations are capable of occurring. leading to blockage of the screen. This phenomenon then requires a total shutdown of the installation to ensure cleaning and unclogging of said screen.

 I1 therefore also appears the need for a process which makes it possible to avoid clogging of a screen ensuring the filtration of pulverulent material and which guarantees the use of the screening plant without risk of malfunction.

To achieve these goals, the invention also relates to a variant of the method for injecting a fluid into a medium with fluid behavior and for mechanical agitation of this medium, applied to the screening of a medium formed of pulverulent material. According to the invention, the method is then characterized in that it consists of
- placing the nozzle in a screening enclosure, upstream of a screen
depending on the direction of flow of the material,
- And to supply the nozzle with pressurized gas to ensure, by the
nozzle movements, mechanical agitation of the material and
vibration of the screen and, by injecting the gas, fluidization
material and blowing in the direction of the screen.

 Various other characteristics will emerge from the description given below with reference to the appended drawings which show, by way of nonlimiting examples, embodiments and implementation of the subject of the invention.

 Fig. 1 illustrates, in schematic axial section, an example of installation in which the method and the device according to the invention are implemented.

 Fig. 2 is an axial section of an embodiment of the injection and agitation device according to the invention.

 Fig. 3 shows, in axial section, an example of a pipe on which the method and the device according to the invention are implemented.

 Figs. 4 to 6 schematically present sieving installations in which variants of the method and of the device in accordance with the invention are used.

 The invention relates, in particular, to a method and a device for injecting a fluid into a medium with fluid behavior and for the mechanical agitation of this medium, method and device which can be implemented on different types of enclosures containing said medium, such as transfer locks, pipes, treatment, storage and / or transport tanks, or the like.

In order to serve as a support for the presentation of a first embodiment of the invention, FIG. 1 shows, by way of illustration but without limitation, an intermediate storage system for various products in powder form.

 Such a system, designated as a whole by the general reference 1, is constituted by a hopper 2 connected to and converging towards a drain pipe 3. The storage system 1 present, at the interface between the hopper 2 and the pipe 3 , a valve 4 for closing the inlet of the latter.

 The system as described above is intended to allow the temporary storage of various products, such as for example chemicals in powder form, before their transport to a packaging and / or treatment installation, not shown and connected. to conduit 3. During this temporary storage, agglomeration or solidification is likely to occur at the bottom of the hopper 2 at the valve 4 which is closed so that, thereafter and when the latter is open, it no longer becomes possible to obtain a normal flow of the material in the conduit 3.

 In accordance with the invention and to allow this flow, the hopper 2 is equipped with at least one and for example with three fluid injection and mechanical stirring devices 10 distributed substantially in the same plane, in three directions defining two at two of the 120 "angles. Given the axial section plane of FIG. 1, only two of these devices 10 appear on the latter.

Of course, the number of devices 10 used and their arrangement are variable and depend mainly on the dimensions and the shape of the enclosure to be fitted. Thus, it would be possible, for example, to use more devices 10, arranged differently, for the fluidization and mechanical agitation of the pulverulent material contained in the hopper 2 illustrated in FIG. 1.

 Each of the devices 10 for fluidization and mechanical agitation consists of an elongated flexible or even flexible nozzle 11 arranged, to extend inside the enclosure defined by the hopper 2. The nozzle 11 has two end parts, one 12, said to be fixed, is immobilized in relation to the wall of the hopper 2 and the other 13, said to be free and opening, is oriented towards the inside of said hopper 2. The end portion 12 of the nozzle 11 is externally connected to the hopper 2 to a supply line 14, coming from a source 15 of pressurized gas which can be of any suitable type known to those skilled in the art. The nozzle 11 can be provided in relation to its fixed end portion 12 with means 16 generating directional variations. Such means 16 can be a bevel cut from the end of the nozzle, oriented nozzles or a remote or flexible end deflector.

 For the illustrated application, the nozzle 11 is advantageously made of a flexible material such as an elastomer which gives it the ability to flex under its own weight when it is held at one end.

 Preferably and in order to facilitate maintenance, the nozzle 11 is removable or extractable from the interior of the hopper 2. To this end, the nozzle 11 is mounted on a nozzle holder 20 connected to the pipe 14 and adaptable with sealing on a sleeve 21 carried by the hopper wall and which the nozzle passes through.

 The above installation allows the implementation of the fluidization and mechanical agitation process according to the invention in the following manner.

 When a supply of pulverulent material is desired, from the hopper 2 towards the conduit 3, the valve 4 is open and the nozzles 11 are supplied with gas under pressure by the source 15. Under the effect of the injection of the gas through the nozzles 11, the pulverulent material is fluidized. In addition, the ejection of the gas at the ends of the nozzles subjects by reaction and due to the flexibility each of the nozzles to a whip movement which causes a random displacement of the terminal part 13. Each of the nozzles ensures by its movements whipping, stirring or mechanical agitation of the pulverulent material and thus improves the flow of the latter. Furthermore, the random movements of end portions 13 allow good distribution and distribution of the fluidizing gas within the pulverulent material.

 The gas used for the fluidization of the pulverulent material can be of any suitable type taking into account, in particular, the nature of the pulverulent material. It can be, for example, a neutral gas, an active gas to ensure treatment of the fluidized material, a gas mixture or the like.

 It appears that the method and the device according to the invention make it possible, by the use of technically simple and inexpensive means, to simultaneously obtain a gas injection in various directions and mechanical agitation, in order to ensure efficient fluidization. middle. The method and the device in accordance with the invention make it possible to avoid the formation of plugs and agglomerates in the pulverulent material and therefore facilitate their flow through the installation, the operation of which is thus made more reliable.

 According to a variant of the method presented above, the supply of cleaning fluid is carried out continuously at constant pressure. According to another variant of the method, the nozzles 11 are supplied intermittently with pressurized fluid. To this end, each of the pipes 14 is controlled by a solenoid valve 35 connected by a line 36 to a control unit 37 which is also connected by a line 38 to the source of pressurized fluid 15. The control unit 37 controls the operation of the source 15 and controls the supply of the nozzles 11, so as to ensure an intermittent supply of the said nozzles to amplify the whip movements of the latter and the random nature of the movements of the injection means 16. According to a different variant of the method, the unit 37 does not provide an intermittent supply of the nozzles 11, but modulates the continuous flow of supply of the latter.

 Fig. 3 illustrates another example of application of the method and the device according to the invention to an enclosure defined by a pipe 30 for transporting fluidized pulverulent material. Line 30 is equipped with an injection and stirring device 10 similar to that described in FIGS. 1 and 2 and which allows the injection of gas into the transported material, as well as the mixing of the latter thanks to the random movements of the nozzle 11.

 To this end, provision may be made to produce the nozzle 11 in such a way that it extends from an elbow 39 so as to have a preorientation, for example parallel to the direction of flow according to the arrow f1. It is obvious, in such a case, that the sleeve and / or the nozzle holder are then adapted to allow a practical assembly and disassembly.

 The method according to the invention can be used in other types of speakers than those presented above and for varied and complementary applications. Thus, fig. 4 illustrates a screening installation designated as a whole by the reference 45, and which comprises an enclosure 46 connected in the upper part, by a conduit 47 to storage and supply means, such as a tank 48 containing pulverulent products . The enclosure 46 is, moreover, connected, at the bottom, to a pipe 49 connected to a processing and / or conditioning unit not shown. The enclosure 46 is equipped with a screen 50 disposed at the outlet of and connected to the supply line 47, so that any material coming from the tank 48 must necessarily pass through the screen 50 to go towards the line 49 To this end, the screen 50 is made of a material having perforations defining non-conforming product retaining meshes. The screen 50 has a substantially cylindrical shape closed opposite the pipe 47, so as to have a screening surface significantly greater than the passage section of said pipe 47. The screen 50 then has a basket shape.

 In order to avoid clogging and blockage of the screen 50 by the pulverulent material coming from the tank 48 and having to be screened, the invention recommends having in the enclosure 46, upstream of the screen 50 relative to the direction of flow. of the pulverulent material illustrated by arrow f2, at least one device for injecting a fluid and mechanical agitation according to the invention.

According to the example illustrated, this device is produced in the form of a tubular body 51 disposed substantially coaxially and internally to the basket forming the screen 50. The tubular body 51 is equipped with at least one but preferably several and, for example , four elongated flexible nozzles 11 adapted by their fixed part i2 on the body 51. The nozzles 11 have a shape substantially similar to that described in relation to FIGS. 1 and 2 and are connected, via the body 51, to a pipe 52 connected to a source of pressurized gas not shown. The device 10, consisting of nozzles 11 fixed to the body 51 in relation to the pipe 52, forms a removable assembly which can be removed from the screen 50 and from the enclosure 46.

 The process for injecting a fluid and mechanical agitation in accordance with the invention consists, during the flow of the pulverulent material coming from the tank 48 in the screen 50, in supplying the nozzles 11 with gas under pressure, so as to obtain by the injection of the gas, a fluidization of the pulverulent material accentuated by the whip movements of the nozzles 11. In addition, the random movements at least of the end portions 13 ensure blowing in the direction of the mesh of the screen 50 contributing thus to their unclogging. This blowing action is, moreover, supplemented by a vibration of the screen 50 under the effect of the whip movements of the nozzles 11 which can be brought into contact with said screen 50. To this end, the dimensions and the relative position of the nozzles 11 with respect to the screen 50 are such that their whipping movements are not hampered but that they are however capable of returning, intermittently, in contact with the walls of the screen.

 The process and the device in accordance with the invention described above advantageously make it possible to avoid any risk of clogging of the sieve during the filtration of the pulverulent material and this thanks to mechanical stirring and fluidization of the material to be sieved, combined with blowing and vibrating the screen during operation.

 In order to ensure evacuation of the injected gas and degassing of the screened pulverulent material, the lower part of the enclosure 46 defines a sort of hopper 46l connected by a chimney 53 to means, not shown, for evacuating the gases.

 After complete screening of the contents of the tank 48, the installation 45 is stopped, the device 10 is then removed to allow the extraction, from the basket screen, of the waste and other refusals of screening.

 Fig. 5 illustrates another embodiment of a screening plant 45 for implementing the method according to the invention.

 According to this other form, the screen 50, disposed in an enclosure 46, is constituted by a substantially horizontal cylinder formed by a grid, the mesh of which defines the fineness of the screening. This cylinder 50 is disposed above a hopper 46l formed by a lower part of the enclosure 46 and intended to collect the sifted pulverulent material. The hopper 46 is connected by a line 49 to a unit, not shown, for processing and / or packaging. Finally, the screen cylinder 50 is connected to a supply system 54 and contains an Archimedes screw 55 ensuring the transport, inside the screen 50, of the pulverulent material to be screened from the supply system 54 to a collecting tank 56 for refusals and other sieving waste. According to the invention, the Archimedes screw 55, which constitutes another embodiment of the injection and stirring device 10, has, in its part located inside the screen 50, at least one and, preferably, several flexible nozzles 11 of the type of those described in relation to FIGS. 1 and 2. The end portions 12 of the nozzles 11 are, according to this embodiment of the device 10, integral with the rotary axis of the screw 55. In order to allow gas to be supplied to the nozzles 11, this axis of the screw 55 is hollow and connected, by a rotary joint 57 and a pipe 58, to a source 15 of pressurized gas. The enclosure 46 is finally connected by the chimney 53 to a system, not shown, for evacuating gases.

 The screen installation 45 described above operates in the following manner.

 The enclosure 46 is supplied, by the system 54, with pulverulent material which is transported inside the screen cylinder 50 by the rotation of the screw 55, driven by motor means 59. During this transport, a fraction , called compliant, material passes through the screen 50 to be collected by the hopper 46l, while the remaining fraction, called waste or refuse, is entrained towards the tank 56. According to the method according to the invention, during all the sieving operation, the nozzles 11 are supplied with gas under pressure to ensure fluidization and agitation of the pulverulent material to be screened, as well as unclogging the mesh of the sieve 50, as explained above in relation with fig. 4. It should be noted that the situation of the injection and stirring device, formed by the nozzles 11 and the screw 55, inside the screen cylinder 50, gives said device a position upstream of the screen 50 by relation to the direction of flow of the pulverulent material which passes through the screen 50.

 Another implementation variant of the object of the invention is illustrated in FIG. 6 according to which the circuit 60 for circulation of a fluid medium such as a charged gaseous fluid comprises a screening enclosure 61 having a mesh filtration unit 62 formed by at least one sleeve 63 carried by a plate 64 preferably removable. The fluid medium to be filtered circulates in the direction of arrow f, and is forced to cross the cuffs 63 to pass from an inlet chamber 65 to an outlet chamber 66 delimited inside the enclosure by the plate 64. The sleeves 63 are open in relation to the chamber 66 in which is provided a cleaning system 67 connected to a source for supplying a pressurized fluid. The installation 67 comprises as many nozzles as there are cuffs into each of which is introduced a tube 68, preferably rigid, provided with a plurality of nozzles 11 which operate as said previously.

 In this example, the unclogging action preferably takes place after the circulation of the fluid to be filtered downstream has stopped, against the current, so that the materials produced are recovered in the bottom 69 of the enclosure 61 from which they can be checked out.

 In the examples illustrated and described, the method and the device according to the invention are implemented in an enclosure containing a medium constituted by pulverulent material, but this device and this method could also be implemented in a tank or enclosure containing a liquid for, for example, ensuring treatment and agitation. In this event, the fluid injected by means of the device could be either a liquid or a gas, depending on the nature of the effect or of the treatment sought.

 The invention is not limited to the examples described and shown, since various modifications can be made thereto without departing from its scope.

Claims (14)

CLAIMS:  1 - Method for injecting a fluid into a medium with a substantially fluid behavior for mechanical agitation and / or for unclogging this medium contained in a transport enclosure (2, 30, 46), storage, treatment or the like, characterized in that it consists of  - have at least one elongated flexible nozzle (11) in the enclosure,  immobilized at a first terminal part (12) which is connected to  a source (15) of pressurized fluid, free at a second part  through terminal (13),  - And supply the nozzle (11) with pressurized fluid to drive, by  reaction, on the one hand, of the whip movements of the nozzle (11) which  agitate the medium and, on the other hand, random displacements of the  end part (13) which directs a jet of fluid into the medium according to  various directions.  2 - Method according to claim 1, characterized in that it consists in supplying the nozzle (11) by varying the pressure of the fluid.  3 - Method according to claim 1 or 2, characterized in that it consists in supplying, intermittently, the nozzle (11) with pressurized fluid.  4 - Method according to one of claims 1 to 3, characterized in that it consists in supplying the nozzle (11) with pressurized liquid.  5 - Method according to one of claims 1 to 3, characterized in that it consists in supplying the nozzle (11) with pressurized gas.  6 - Method according to claim 5, characterized in that it consists in supplying the nozzle (11) with pressurized gas to ensure the fluidization of a medium formed of pulverulent material.  7 - Method according to claim 6, characterized in that it consists of  - arrange the nozzle (11) in a screening enclosure (46), upstream  a sieve (50) according to the direction of flow of the material,  - And supply the nozzle (11) with pressurized gas to ensure, by the  nozzle movements, mechanical agitation of the material and  vibration of the screen and, by injecting the gas, fluidization  material and blowing in the direction of the screen.  8 - Method according to claim 6, characterized in that it consists in placing the nozzle (11) in a screening filtration unit (62) downstream of a screen (63) relative to the direction of flow of the fluid to sift.  9 - Device for injecting a fluid into a medium with a substantially fluid behavior for mechanical agitation and / or for unclogging this medium contained in a transport, storage, treatment or similar enclosure, characterized in that that it comprises at least one elongated flexible nozzle (11) which is disposed inside the enclosure (2, 46) and which has  - a fixed terminal part (12) connected to a pipe  supply (14) of pressurized fluid,  - a free and opening end portion (13).  10 - Device according to claim 9, characterized in that the terminal part (12) is mounted on the enclosure by removable connection means.  11 - Installation for implementing the method according to one of claims 1 to 8 in an enclosure (2, 30, 46) for transport, storage, treatment or the like which contains a medium with a substantially fluid behavior, characterized in what she understands  - a source (15) of pressurized fluid,  - and at least one device (10) according to one of claims 8 to 13,  arranged in the enclosure and connected to the fluid source.  12 - Installation for the implementation of the method according to claim 8, in an enclosure (46) which has a screen (50) for the screening of a fluid medium, characterized in that it comprises  - a source of pressurized gas,  - at least one injection and stirring device according to the  claim 9, connected to the source of pressurized gas and disposed  near the screen (50) to ensure by the movements of the  nozzle (11) mechanical agitation of the material and  vibration of the sieve and, by the injection of gas, a fluidization of the  material and blowing in the direction of the sieve,  - and a system for evacuating the injected gas to ensure degassing of  the sieved matter.  13 - Installation according to claim 12, characterized in that the nozzle is arranged upstream of the filter screen relative to the direction of circulation of the fluid medium.  14 - Installation according to claim 12, characterized in that the nozzle is arranged downstream of the filter screen with respect to the direction of circulation of the fluid medium.