FR2681053A1 - Vibration method and device for evacuating solid products in the divided-up state from a storage volume - Google Patents

Abstract

The technical sector of the invention is that of the construction of equipment for storing and handling pulverulent or granular solid products. It is a vibration device for evacuating solid products (2) in the divided-up state from a storage volume (1) suspended by its top part from a framework (8), and through an evacuation orifice (23) located in the bottom part of this volume in the shape of a downward converging cone. This device comprises: - means (11) of suspension and connection allowing both small relative displacements between the said storage volume (1) and the said framework (8) and the taking of all of the weight of this volume (1) and of the products (2) which are stored in it, any rotary drive means (5) fixed on the said framework (8), a rotary device for throwing off-centre whose fixed part is integral along at least one axis of translation perpendicular to its axis of rotation (XX') with the said volume (1) at the level of the lower section of the latter, where the said evacuation orifice (23) is located and whose mobile part (16) is connected to the shaft of the said rotary drive means (5).

Description

Method and device for vibrating the evacuation of products
solids in the divided state from a storage volume.

DESCRIPTION
The present method relates to vibrating methods and devices for the evacuation of solid products in the divided state from a storage volume.

 The technical sector of the invention is that of the construction of equipment for the storage and handling of solid, pulverulent or grain products.

 One of the main applications of the invention is that of flexible elevators or conveyors of products to be evacuated from a storage hopper, which elevators or conveyors are composed of a flexible tubular sheath and of a helical coil also flexible and which is rotated inside said sheath. This helical turn may consist of a wire wound in a helix like a helical spring or of a helical brush consisting of strands implanted in a helix on a flexible axial rod.

Such a flexible conveyor device is described in patent application EP 0051 550 filed on 10/22/1981 by the Company
Anonymous TRANSITUBE PROJET and the present invention can also be applied to other types of evacuation, carriers or elevators from silos with other systems such as those with Archimedes screw or even direct emptying by gravity.

 Many devices are known for extracting products in the divided state from a storage bin, such as a hopper or silo, but when these products are of low density and / or a little sticky, they can be arched above the discharge orifice generally located at the bottom of the tank and in which said extraction device operates when there is one; this arch is all the more difficult to break when the quantity of products located above is large and packed. To try to avoid this arching and improve the extraction rate, various manufacturers add so-called stuffing blades which are driven rotating around the discharge orifice and which are inclined towards the center thereof, such as for example in patent application EP 0315 403 filed on 11/01/1988 by the Finnish Company A. AHLSTROM Corporation: this solution requires a large drive power increasing the cost of the device and has many practical drawbacks; on the one hand the blades tire and can break, on the other hand the bottom of the storage tank is then difficult to clean if you want to change the product for example, or after each operation when it comes to food products, and finally this rotation of the products can deteriorate them by friction against the walls and the blades, and on themselves, which can be very annoying, in particular for food products; one can also note the problems of product centrifugation which can then separate by density and thus make it difficult to maintain homogeneous mixtures.

To avoid these numerous drawbacks and depending on the products concerned, other manufacturers use vibrator systems which vibrate the products to prevent them from arching and among which is the present invention: for example, this domain patent application FR 2648443 filed on 06/14/1989 by the company SETEC GEOTECHNIQUE on a "shutter for dosing hopper of particulate products" comprising a helmet containing unbalanced vibrators in the vertical direction avoiding on the one hand the formation of arch and on the other hand the adhesion of the product on wings integral with said helmet; there is also the patent application FR 2612088 filed on 12/03/1987 by LES
CHARBONNAGES DE FRANCE on "a very fine powder distributor" comprising an Archimedes screw in a discharge tube into which a vibrating needle is inserted from below. These various systems act directly on the products to set them in vibration, and as this only concerns the internal volume in the vicinity of the discharge orifice, the arch effect can still occur above, out of reach vibration systems which then vibrate only in the air.

 Other systems are also used in an attempt to vibrate all of the stored products: these are mechanical vibrators which are placed directly against the external walls of the storage tanks to transmit vibrations by vibrating with them ; the necessary energy is then important, and to be effective it is used high frequencies, which then deteriorates the structural welds and acts, by definition and objective, on the whole mass of the products beyond what would only be necessary to avoid the vaulting effect, which products stuff and clog in the evacuation orifice, settling in the tank and increasing the possibility of vaulting, then requiring increasing the vibration energy, which leads to mechanical deterioration and an increase in said packing. If the frequency of vibrations is reduced, their effectiveness decreases, unless the amplitudes of movement are increased, which would complicate the system for fixing the tanks and the storage volume. and would in any case create risks of rupture by fatigue.

 The problem is therefore to be able to evacuate from a storage tank or volume, without risk of arching above the evacuation orifice, solid products in the divided state, using a system which does not damage mechanical installations, welds or connecting elements of said storage volume and its frame, in which products are stored, which does not require a significant supply and transmission of energy, and which facilitates the evacuation of said products to the divided state.

One solution to the problem posed is a method for storage volumes comprising a discharge orifice situated in their lower part in the shape of a cone converging downwards, such as
the upper part of said volume is suspended from a frame by any means allowing both small relative displacements and taking up the entire weight of said volume, the products stored therein and any mechanics associated with said volume ,
- any rotary drive means are fixed on said frame,
- It connects the axis of said means to the movable part of a rotary eccentric which the fixed part is secured, along at least one axis of translation perpendicular to its axis of rotation XX 'to said volume, at the lower part of that -where the said discharge orifice is located,
- Said means is rotated at a rotational speed of less than 2000 revolutions / second during the entire desired evacuation time of said products through the orifice.

Another solution to the problem posed is a vibration device for the evacuation of solid products in the divided state from a storage volume, suspended by its upper part from a frame, and through a orifice. discharge located in the lower part of this cone-shaped volume converging downwards, as it comprises
suspension and connection means allowing both small relative displacements between said storage volume and said frame, and to take up the entire weight of this volume, of the products stored therein and of any mechanics associated with said volume ,
- any rotary drive means fixed on said frame,
a rotary eccentricator, the fixed part of which is secured, along at least one axis of translation perpendicular to its axis of rotation XX ′, at said volume at the level of the lower part of the latter where said discharge orifice is located and whose movable part is connected to the axis of said rotary drive means.

In a preferred embodiment, the axis XX ′ of said rotary eccentric is placed horizontal and the fixed part thereof is fixed to the side of said volume 1; in this case, two of said connection and suspension means can be positioned at two points of said storage tank, situated in the vertical plane passing through the axis
XX 'of said rotary offset. This facilitates the vibration of the lower part of the tank by rotation around these two suspension points without forcing on the corresponding connection means.

 According to a preferred embodiment, the speed of rotation of the movable part of the eccentric is from 500 to 1000 revolutions / second and the minimum displacement in translation perpendicular to its axis of rotation XX 'and caused by said eccentric is i millimeter.

 The result is new vibration methods and devices for the evacuation of solid products in the divided state from a storage volume, especially when said products are of low density, for example less than 0.6, and are sticky or vaulting such as coffee powder, cocoa, flour, but also plastic particles like those obtained in the context of their recycling, because they then form small parts which overlap each other in the others and therefore descend with difficulty by their own weight.

 The methods and devices according to the invention therefore avoid the vaulting of these products, and even facilitate their evacuation at the entrance of the evacuation duct: a drive system of elevator type or flexible conveyor can be associated with this type of vibrator. since then the flexibility of the conduit and the internal propeller absorbs said vibrations without transmitting them to the rest of the installation of other more rigid systems can also be associated by hanging them also like the hopper or the storage tank with systems accepting these vibrations, like shock absorbers.

 In the present invention, it is especially the lower part of the storage tank or volume which vibrates, and the upper part pivoting only on its suspension points only undergoes small amplitudes of the movement caused by the eccentricator in the lower part: thus , it is especially the products located in this part which are solicited, avoiding that it is the whole mass of these which is it and which would then risk to settle as in the current systems of global vibration. invention, the axes, the planes and the amplitudes of the vibrations and therefore of movement of the systems are controlled, which makes it possible to size and position the suspension and connection points with the other members of the installation accordingly, limiting their fatigue and their premature deterioration; while current vibration systems are multidirectional and do not prevent such deterioration. This mechanical control of the vibration then makes it possible to choose the best frequency to optimize the desired effect because if the frequency is too low, the vibration is almost unnecessary, and if it is too high, the mechanical parts are stressed too much as in current systems and welds; these may then drop, with in addition excessive compaction of the products and a jam at the inlet of the discharge orifice which goes beyond what is strictly necessary and even against the desired goal .

 We could cite other advantages of the present invention, but those mentioned above already show enough to demonstrate its novelty and interest.

 The description and the figures below represent exemplary embodiments of the invention but are in no way limiting: other embodiments are possible within the scope and scope of this invention, in particular by changing the means for driving the eccentrics in rotation causing the desired vibration, as well as all the evacuation means and the shape of the storage tank.

 Figure 1 is a side view of an example of an assembly of a device according to the invention, allowing also to carry out the method thereof.

 Figure 2 is a sectional view of a vibration offset.

 Figure 3 is a side view of another example of a system according to the invention.

 Figure 4 is a side view of another example of device assembly according to the invention.

 FIG. 1 is a side view of an assembly comprising a storage volume 1 of divided products 2 that is loaded at the top of this volume 1 either directly or by connection to the top of its opening with a tarpaulin or any other generally flexible additional volume as is the case with many transport containers in which the products are placed which are then to be transferred into said storage volume 1. This is then considered as a buffer storage tank whose hopper generally comprises a vertical cylindrical upper part and a conical lower part which converges downwards and whose volume, in the present invention is as small as possible, because the result of the vibration such as described above and below will concern all the more only the conical part, which is sufficient for the desired result; above, the tarpaulin or the container which is placed over it does not need and should not vibrate too much to avoid settlement problems already reported. As an example, we can consider that the hopper, or the tank or storage volume, 1 is a volume of the order of 200 dm3, while the container 3 or tarpaulin which can be connected above can have a volume of the order of 1 m3.

 In this figure there is shown with the storage system an evacuation system through an orifice 23 located in the wall of the conical part of said hopper 1 such as a flexible coil device 6 in which said coil is rotated by a motor 4 inside a flexible tube 7 connected to said orifice 23.

This allows in this case a horizontal discharge in any desired direction 17. In this figure the drive motor of said evacuation system is located at the end passing in and through the lower part of the storage tank, but in other embodiments such as in fig 4 the motor d drive 4 can be located at the other end of the drive coil without therefore being integral with said storage tank 1.

 In the present invention, this evacuation and drive system is however not necessary, because the evacuation of the product could be done directly by gravity with an orifice 23 located at the lower part preferably then in the axis of the hopper, the products can then fall by gravity into another tank or any other system that would be located below.

 The present invention effectively and essentially relates to the vibration device proper which makes it possible to solve the problem posed for the evacuation of solid products 2 in the divided state which would risk being arched above said evacuation orifice 23 and which could thus no longer be removed from said storage volume 1.

The vibration device according to the invention in fact essentially comprises
- It suspension and connection means allowing both small relative displacements between said storage volume 1 and its support frame 8, and to take up the whole of the weight of this volume 1, of the products 2 which are stored there and any mechanics associated with said volume 1,
- any rotary drive means 5 fixed on said frame 8,
a rotary eccentricator, the fixed part of which is secured, along at least one translation axis perpendicular to its axis of rotation XX ′, at said volume 1 at the level of the lower part thereof where said discharge orifice 23 is located, and the mobile part 16 of which is connected to the axis of said rotary drive means 5.

 Preferably, said connection means 11 are elastic dampers, and two of said connection and suspension means 11 are positioned at two points of the storage tank 1 situated in the vertical plane passing through the axis XX 'of said rotary eccentric, this is all the more interesting and useful when the axis XX 'of said rotary eccentric is horizontal as shown in Figure 4 and the fixed part thereof as described in fig 2 is fixed on the side of said volume 1. Indeed , then, the vibration of the lower part generates only a rotational movement relative to said connecting means located at the two suspension points defined above, thus avoiding efforts in said suspension means.

 In the representation of FIG. 1, the axis XX ′ of said rotary eccentricator is represented vertical and the drive system thereof is represented by a motor 5, integral with an element or arm 10 of the support frame of the storage bin 8, itself resting on the ground, for example by feet 9. In this example of embodiment, any known conveyor system has been installed in the bottom of the volume and through the orifice 23 made in the wall using a cylindrical conduit 7 connected to said orifice 23 and in which a means 6 for driving the products 2 is rotated; this system, already defined above, can be a flexible means, said drive means 4 being able to be a motor independent of that allowing the vibration, which motor is fixed on the hopper or storage tank 1 and therefore vibrates with it. In this representation, the vibration of the lower part of the hopper is therefore caused in a horizontal plane and the upper suspension points 11 therefore simply receive a lateral displacement with a small relative rocking effect.

 Figure 2 is a section AA 'of the eccentric 13 connecting the drive system, or motor, 5 to the lower part of the hopper 1 as shown in Figure 1 but also in Figures 3 and 4. This eccentric consists of an outer bearing 13 constituting the fixed part of said eccentricator, connected integrally to the object to be vibrated, or here the storage volume i, at least along a translation axis YY 'perpendicular to its axis of rotation 14 XX '. According to the other axis of translation ZZ 'perpendicular to said axis XX' the whole of the eccentricator can be free to move thanks to a guide between two slides 24 thus integral with the storage bin 1. This assembly is advantageous in the example in FIG. 4 in particular, thus allowing vibration only along the axis YY ′ which, if it is situated in the horizontal plane, causes said hopper 1 to vibrate only in this plane without there being any vibration in the axis ZZ 'which is then vertical and which would cause the lifting of the entire hopper when the axis of rotation i4 XX' is horizontal.

 Furthermore, said eccenter may comprise, in a known manner, a ball bearing 15 situated inside the bearing of the fixed part 13 and an inner ring 16 whose axis 14 is eccentric relative to said ball bearing d 'a distance (b - a) corresponding to twice the distance of its axis relative to that of the part of the movable ring of the eccentricizer 16 as shown in Figure 2. The drive means or motor 5 is then connected by its axis, to the axis of the eccentric ring 14.

In a preferred embodiment, as recalled above, the amplitude of vibration corresponding to the distance (b - a) is preferably at least 1 millimeter and at most 2 millimeters to avoid too great a range of motion. This is in any case sufficient when the rotation speed and therefore the vibration frequency transmitted to the storage tank is from 500 to 1000
Hz.

 Figure 3 is another example of an installation using a method according to the invention and in which devices according to the invention are mounted. In this figure, said means 5, of drive for vibrating, are used to also rotate said drive means 6 for discharging products 2 from the interior of the hopper 1.

 In this exemplary embodiment, the evacuation means is shown vertical for an evacuation 17 situated in the hopper itself and upwards, but it could also be mounted horizontally, as in FIG. 1, also with a single drive motor for evacuation and vibration.

 In this figure, the entire hopper is shown on a frame placed on legs 9 comprising at the lower part of the wheels 22 allowing movement of the assembly by means of handles 20. The frame can also be covered with a fairing 19 and the hopper can be closed by a cover 18. The damping systems 11 are shown here in the form of elastic elements in diabolo. The hopper comprises at this lower part, conical like the whole of the hopper, a drain hatch 21 which allows direct access to the bottom of the tank, since the latter does not include any blade that could hinder cleaning of this lower part.

 Figure 4 is another embodiment of the method and the device according to the invention in which the axis of the discharge orifice 23 is horizontal as in Figure 1, with a drive motor located at the end flexible means 7 outside said hopper; the inspection hatch 21 is located in the axis at the lower vertical part of the conical part of the hopper. The vibration drive system consists of a motor 5 connected to the frame by a cross-support 10, which frame can be placed by feet 22 on the ground, and supporting at the top the shock absorbers 11 connected to the hopper 1 by support angles 12. The eccenter is then, preferably in this position, of horizontal axis XX ′, connected to the lower part of the hopper by means of vertical angles 24 canceling vertical vibration movements which can be transmitted to the hopper and not allowing the transmission of vibrations only in the lateral horizontal plane, as defined in Figure 2. Similarly and preferably, the axis of the discharge orifice 23 is located in the same plane as the axis of the drive means XX ′, also that of the two said suspension points 11 defined above, thus ensuring a pendulum effect on the entire hopper relative to this evacuation axis, fa cilitating the force-feeding of the product in the evacuation.

Claims (10)

 1. Method for facilitating the evacuation of solid products (2) in the divided state from a storage volume (1) and through an evacuation orifice (23) located in the lower part thereof cone-shaped converging downwards, characterized in that  - The upper part of said volume (1) is suspended from a frame (8) by any means (11) allowing both small relative displacements and taking up the entire weight of the volume (1), products stored there (2) and any mechanics associated with said volume (1),  - any rotary drive means (5) are fixed on said frame (8),  - One connects the axis of said means (5) to the movable part (16) of a rotary eccentric which is fixed to the fixed part (13), along at least one axis of translation perpendicular to its axis of rotation XX ', said volume (1) at the level of the lower part thereof where said evacuation orifice (23) is located,  - Said means (5) are rotated at a speed of rotation of less than 2000 revolutions per second during the entire desired evacuation time of said products (2) through the orifice (23).  2. Method according to claim 1 characterized in that installed in the bottom of said volume and through the orifice (23) any known conveyor system using a cylindrical conduit (7) connected to said orifice and in which a means (6) for driving the products (2).  3. Method according to claim 2 characterized in that said means (5) is used to rotate that of drive (6) of the products (2)  4. Vibration device for the evacuation of solid products (2) in the divided state from a storage volume (1), suspended by its upper part from a frame (8), and through a evacuation orifice (23) located in the lower part of this cone-shaped volume converging downwards, characterized in that it comprises  - Means (11) for suspension and connection allowing both small relative displacements between said storage volume (1) and said frame (8), and to take up the entire weight of this volume (1), products (2) stored there and any mechanics associated with said volume (1),  - any rotary drive means (5) fixed on said frame (8),  a rotary eccentricator, the fixed part of which is secured, along at least one axis of translation perpendicular to its axis of rotation (XX ′), to said volume (1) at the level of the lower part thereof where said orifice d 'evacuation (23) and whose movable part (16) is connected to the axis of said rotary drive means (5).  5. Vibration device according to claim 4 characterized in that said connecting means (11) are elastic dampers.  6. A vibration device according to any one of claims 4 and 5 characterized in that the axis XX 'of said rotary offset is horizontal and the fixed part thereof is fixed on the side of said volume (1).  7. A vibration device according to claim 6 characterized in that two of said means (11) for connection and suspension are positioned at two points of said storage tank (1), located in the vertical plane passing through the axis XX 'of said rotary offset.  8. A vibration device according to any one of claims 6 and 7 characterized in that the axis of the discharge orifice (23) is in the same vertical plane as the axis XX 'of the eccentricator.  9. A vibration device according to any one of claims 4 and 5 characterized in that the axis XX 'of said rotary eccentricator is vertical and located in the axis of the lower part of the volume (1).  10. A vibration device according to any one of claims 4 to 10 characterized in that the rotational driving speed of the movable part (16) of the eccentricator is 500 to 1000 revolutions / second and the minimum displacement in translation perpendicular to its axis of rotation XX ′ and caused by said eccentricator is 1 millimeter.