FR2479160A1 - PROCESS FOR COMPRESSING AND HOMOGENIZING BULK MATERIAL - Google Patents

Abstract

PROCESS OF PACKING AND HOMOGENEIZATION OF BULK MATERIAL IN A PRACTICALLY ENDLESS ANNULAR HALDE, WITH A TRIANGULAR STRAIGHT SECTION, ACCORDING TO WHICH THE BULK MATERIAL IS DISCHARGED ALONG THE MIDDLE ZONE OF THE RING WITH AN OSCILLATION MOVEMENT IN THE HORIZONTAL PLANE WITH A CONSTANT CENTER ANGLE, BACK-AND-BACK AND PROGRESSING IN ONE DIRECTION, AND THUS IS PACKED IN LAYERS, THEN IS REMOVED FROM THE BASE OF THE FRONT SIDE OF THE ANNULAR HALDE, UNDERLYING THE ANGLE OF NATURAL FLOW, IN RADIAL DIRECTION. THE BACK-AND-BACK OSCILLATION MOVEMENT IS MOVING AT A SENSITIVELY CONSTANT SPEED, EXCEPT IN ZONES OF SENSE CHANGE, AND THUS THE LAYERS ARE DEPOSITED SENSITIVELY IN THE SHAPE OF A PARABOLA, THE THICKNESS OF THE LAYERS INCREASING BY INCREASING THE TOP THE HALDE AT ITS BASE. FIGURE 3 ATTACHED ALLOWS THE COMPARISON OF THE PARABOLIC SHAPE OF THE LAYERS WITH THE STRAIGHT-LINE SHAPE OF THE LAYERS OBTAINED BY A KNOWN PROCESS.

Description

-1

  The present invention relates to a process for

  and homogenisation of bulk material in a virtually endless annular

  triangular, according to which the bulk material is

  along the median zone of the ring with oscillatory movement produced in the horizontal plane with a constant center angle, reciprocating and advancing in one direction, and is thus piled up or piled up in layers, and is removed, during homogenization, from the base on the front side of the annular heap, underlying

  the natural angle of repose, in the radial direction.

  Such a process is already known from German Patent No. 1,432,040. The installation for carrying out the process described in this patent has, in the middle of a circular surface, a vertical axis around which a

  radially circulating conveyor belt achieves the movement

  progressive oscillation in the horizontal plane. The conveyor belt is supplied with bulk material by a

  other carrier in the area of the axis. The transpor-

  The machine then transports the bulk material radially outwards, its unloading end defining the

  median radius of the existing ring wall. The annual

  nular builds up in layers gradually through a movement.

  oscillation of the conveyor belt, progressing in

  a direction, which is done with a constant center angle.

  The existing pile has a cross section

  triangular and divides at each stage of its construction.

  two parts or sections, namely a part or - 2 -

  section and a part or section of tran-

  sition, in which the height of the pile and the width of the base go down little by little to zero. The part

  transition is ultimately defined by the area of

  the section swept each time by the unloading end of the conveyor belt. The heaped layers are inclined relative to the horizontal plane and are flat when viewed in a section developed along the median circumference of the ring; they are substantially parallel to one another and have substantially equal thicknesses as well as equal lengths. For

  to obtain such layers, it is necessary - assuming a

  Constant conveyance of the conveyor belt - that the oscillating movement of the conveyor belt takes place at variable angular speed, and at the same time the angular velocity at the exit of the conveyor must be as great as possible and that it is the smallest possible

  at the outlet of the transition part in the upper part of the

  total halide. In this case, in order to obtain layers of constant thickness, the volume piled up or piled up per unit length of the transition part, because of the height that grows linearly in a progressive manner

  up to the total height of dump, must therefore increase.

  The removal of the annular ring of the ring from its front side is done according to German Patent No.

  1.432.040 using a circulating removal device

  radially, which can be constituted by a worm,

  a harrow or other conveyor device, and which transmits

  carries the material in bulk, radially inward, to a downwardly directed discharge well provided at the center of the circular surface which contains the annular heap. The removal device described, around

  the vertical axis in the middle of the circular surface

  a circular motion which is always directed towards the front side of the pile and which is coordinated with the forward movement of the conveyor belt. Since the removal layers obtained in this way form with the filler layers a determined constant angle (the

  direction of delivery and the direction of removal are

- 3 -

  to each other), the effect of homogeneity is obtained

known situation. 1

  The known method has a series of disadvantages.

  First, the area of the pile defined by the circular surface

  is not used optimally, that is to say

  that the volume of halide that can be used for storage is

  latively small. This is due to the fact that the ridge of the pile falls linearly in the transition part, this

  which restricts the volume of the sensitive transition part-

  the volume of a pyramid with three curved sides. As still opposed, according to the known method, to a zone

  the greatest possible oscillation of the transport band

  Therefore, the volume of usable storage hade represents only one-third of the volume of a constant-height annular heap, which corresponds to the maximum height of the transition part. An additional disadvantage

  because of the variable angular speed of the transport band

  which requires a training device.

  and expensive control because of the relatively large mass to move. It must be added that just when the direction of oscillation at the outlet end of the pile is reversed, the angular velocity must be as great as possible, which causes difficulties in

because of inertia.

  The object of the invention is to improve the

  briefly described above so that

  aforementioned convinients are no longer present. This objective

  tif is achieved, according to the invention, thanks to the fact that the reciprocating oscillation movement is made at a substantially constant speed, except in the zones of change of direction, and thus the layers are deposited substantially in the form of parabolas - sectional views along the median circumference of the ring -, the thickness of the layers going

  increasing from the top of the dump to its base.

  The means proposed make it possible to

  and control of the device which distributes the material in bulk (the conveyor belt for example) in the simplest possible way. In addition, the big problems posed by

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  Inertia forces are no longer present in the direction change zone at the outlet end of the pile, since it is no longer necessary to brake suddenly at a high speed to the immobilization then to speed up again at this high speed. The constant oscillation speed im-

  that the thickness of the layers of the transition part

  gradually decreases from the base of the pile to the

  the total weight of the pile because it has a

  The aunt of the bulk material, the heaped volume per unit length, and thus the cross sectional area of the layers remain constant, but the shape of the cross-section of the layers becomes more and more elongated as the height of the the transition part increases (the section

  right of the layers consists of two bands, which are

  wind on the outer face of the sides of the triangular cross section of the transition part already stacked). As a result, the layers seen in a section developed along the median circumference of the ring - are of substantially parabolic shape. But this means that, at the maximum equal height of halide and equal-length of the transition part, the volume of the packed transition part according to the invention is greater than the volume stacked according to the known method, because according to the In the transition part, the crest of the ladder descends substantially in a parabola, whereas, when the known method is used, it descends to the base along a straight line. The volume of the transition part according to the invention is 50% greater than the volume of the transition part obtained with the known method. It can thus be seen that the volume of halide that can be used for storage is increased by the invention,

  Circular surface and height of data.

  But the invention provides yet another advantage.

  Due to the fact that at constant transport capacity of the bulk material the volume packed per unit length of each layer remains substantially the same, the bulk material is subjected everywhere, along each layer, to flow conditions substantially. equivalents (with a substantially constant filling time per unit length of the layer), which has a favorable influence on the preservation of the bulk material as well as on the homogenization obtained by

  the subsequent removal of the pile.

  To further improve the care of the material

  in bulk, it is recommended to overlay the movement -

  oscillating back and forth at a substantially constant speed

  a rising and falling movement at varying speeds.

  ble adapted to the parabolic shape of the layers. It is pos-

  in this way, to minimize the flow distance, and hence the flow time, of the material

  in bulk, because the fall of bulk material is always

  days at a substantially constant distance from the ridge of

the already packed pile.

  The invention will be better understood using the

description below.

  In the accompanying drawing Figure 1 shows an overall view of an annular heap stacked according to the invention in oblique profile; Figure 2 shows a section developed along the median annular circumference of the pile of Figure 1; and,

  Figure 3 is an enlarged section of Figure 2.

  The annular loop according to Figure 1 has a portion A - B at total height and a transition portion B - C whose peak descends to the base of the pile along a parabola (Figure 2). The front side of the pile extends, as shown particularly in Figure 2, according to the natural angle of repose of the bulk material. In Figure 1 are shown schematically,

  on the front side, a few layers, and one can meet

  It should be noted that the cross-sectional areas of the layers are equal, but that the layer thicknesses

  decrease from the bottom up (or from the inside towards the ex-

  TER AL). In Figure 2 are illustrated the different parabolic layers and becoming thicker towards the base of the pile. EL indicates the advance of the pile by stacked layer.

  Figure 3 serves to explain an additional advantage

  The process according to the invention is compared to the process known from German Patent No. 1,432,040. L indicates the

  length of the oscillation zone (measured on the circumference

  median annulus) and thus the base length of the transition portion B-C. As shown, the total height of the pile is reached, for example, by stacking, according to the invention, six parabolic layers; the parabolic layers are numbered from 1 to 6. If we now pile up in a transition part at base length and at the level of halide equal according to the known method, parallel layers whose constant thickness would correspond to the thickness of the lowest layer of a parabolic layer according to the invention, it would be possible to set up only about three of these layers; these right oblique layers are

  represented in FIG. 3 and are numbered from 1 to 3.

  It follows therefore that with the method according to the invention, under equal geometric conditions, one can pile up about twice as many layers as with the known method, which

  has a favorable effect on homogenization.

  It can further be seen immediately in FIG. 3 that the packed transition part according to the invention has a larger volume than the transition part according to the known method; indeed, the ridge parabola connecting points B and C is above the straight ridge connecting points B and C. -7-

Claims (2)

  A method of packing and homogenization of bulk material in a substantially endless annular heap, of triangular cross-section, in which the bulk material is discharged along the median zone of the ring formed by the pile, with an oscillation movement produced in the horizontal plane with a constant center angle, back and forth and progressing in one direction, and is   thus stacked in layers, and is removed during the homo-   genesis, from the base of the frontal side of the annular   o0 lar, underlying the natural landslide angle, in the radial direction, characterized in that the reciprocating oscillation movement is made at substantially constant speed, except in the areas of change of direction , and thus the layers are deposited substantially in the form of 415 parabolas - sectional views along the median circumference of the ring -, the thickness of the layers increasing. from the top of the dump to its base.   2- Method according to claim 1, characterized   in that we superimpose the oscillation movement in va-and-   comes at a substantially constant speed a movement of   variable speed, adapted to the shape parabolic layers.