FR2498486A1 - Air stream separator for mixtures - has inclined section of secondary conveyor to catch heavier fraction of conveyed material from first conveyor - Google Patents

Abstract

The air stream separator has a conveyor and a fan with an air nozzle at the output end of the conveyor to produce an air stream inclined upward in the conveying direction. The conveyor (31) is a vibrating conveyor at which the heavier fraction is collected on its bottom. An additional conveyor is located in the conveying direction after the output end, and located below it. The additional conveyor (32) has an upwardly inclined portion (37) at its input end which becomes parallel with the main conveying direction. The heavier fractions drop down on the inclined portion and are conveyed down it.

Description

 The invention relates to a blower particle separator intended for example to sort chips or biological masses.

 In a blower separator, the material to be sorted is introduced in the mixed state into the air stream, so as to divide into two parts, the lighter part of which follows the direction of the air stream.

 In the initial separation phase, that is to say when the material is introduced into the stream of separation air, this material is sorted only after having traveled a certain distance at the end of which the particles, for example the heavier ones are separated from the others. The distance over which the material remains without being sorted can be relatively long, which is a drawback because the blower separation installation must then have very large dimensions.

 When the starting material from which we want to separate, for example stones or metallic particles, consists of a set of particles having roughly the same size and the same density, the heavy particles can be separated by the air stream , according to the prior art, without affecting the distribution of the particles in the material.

 On the contrary, when the light particles form a mixture of particles of variable densities and / or sizes, the separation by blower according to the prior art has the result that even if it is easy to separate all of the light particles, those with the same properties tend to come together. A starting material whose particles of different characteristics form a homogeneous mixture, therefore tends, after separation by the air flow from the blower, to form a partially inhomogeneous mixture classified by size and / or density of the particles. many industrial applications one wishes to use a homogeneous mixture. A separation by air blower according to the prior art therefore has the disadvantage that the small particles from which the stones for example have been removed, tend, after separation, to be divided into fractions of identical particle sizes.

 It is also very desirable to be able to separate stones and other heavy impurities, from biological masses comprising in themselves heavy elements such as strains of branches or the like.

 The invention aims to overcome the above drawbacks of the prior art by creating an apparatus capable of giving a homogeneous mixture of materials after separation by air blower, this result also being obtained in the case of biological bodies or biomass.

 To this end, the invention relates to a blower particle separator intended to separate the heaviest fraction, constituted for example by stones, of a mixture of lighter particles of different properties, constituted for example by shavings, this separator comprising a conveyor and a fan or any similar means provided with an air blower nozzle placed at the outlet end of the conveyor and capable of producing an air current inclined upward and forward in the direction advancement of the conveyor, separator characterized in that the conveyor is of the vibrating conveyor type in the bottom of which accumulates the fraction of heavy particles, in that an additional vibrating conveyor is placed, in the direction of advancement, after ltextrdmitd at the outlet of the conveyor and at a lower level than the latter, so as to cooperate with it, this additional conveyor being provided at its outlet end with an upwardly inclined part transforming into a part parallel to the main direction of the conveyor, this inclined part being arranged, with respect to the outlet end of the first conveyor so that the heavy fraction of the particles falls on this part carrying them downward.

The invention will be described in detail by means of the attached drawings in which:
- Figure 1 is a longitudinal sectional view of a blower particle separator corresponding to a first embodiment of the invention;
- Figure 2 shows a part of Figure 1 in which the trajectories of the particles are indicated;
- fig reX3 is a longitudinal section view of a blower particle separator corresponding to a second embodiment of the invention;
- Figures i and z show a part of the separator of Figure 3 respectively corresponding to two or three possible embodiments;
- Figure 6 is a sectional view of an embodiment of tilting slide.

 The object of the invention is to separate, by air blower, a homogeneous mixture of particles. For this, the material from which we want to separate the heaviest particles advances for example on three vibrating conveyors, called tilting ramps, placed one above the other, to reach three individual air blowers whose jets are inclined towards the top in the direction of travel. When the material is brought to the separation air blower on a tilting ramp, the heavy fraction is collected at the bottom of the material flow, when this material consists for example of small chips mixed with stones or heavy metal pieces .

 A practically immediate separation of the heavy fraction is obtained when the tilting ramp ends with an air blower nozzle directed slightly upwards in the direction of advance, this blower ejecting light chips in a direction coinciding exactly with the flow of air. The heavy fraction consisting for example of stones gathering in the bottom of the tilting ramp, falls at the end of the ramp and beyond the blower nozzle, on an inclined plane thus allowing it to be separated from the light fraction, by transport opposite to the direction of transport of the tilting ramps above. The light fraction can then be subjected to a stream of turbulent air which does not separate, thereby avoiding the agglomeration of identical particles by giving a homogeneous mixture of this fraction 1v manages.

 the blower separator shown by way of example in FIG. 1 can be used for example to separate stones and other heavy particles, chips or chips, before these chips are used and processed in the pulp industry to paper.

 In a first embodiment, the separator according to the invention comprex ^ d a number of tilting ramps mounted in a housing 1 e This housing is set in motion by a vibrating device 2 which causes the movement of the housing according to the arrows 3 0 The shavings are sent downwards by entering through an inlet opening 4, and fall on three tilting ramps 5a, 5b, 5c distributing the shavings between them so as to obtain on each ramp a layer of suitable thickness.

 The ramps are rigidly mounted in the casing 1 and their movement causes the chips to advance until they reach three air nozzles 11a, 17b, 17c placed one above the other. The air jets ejected by these nozzles 17a, 17b, 17c are inclined upward in the direction of advancement of the chips. These are driven out of the tilting ramps 5a, 5b, 5c, by the air blowers 7a,, b, 7c starting from the nozzles 17a, 17b, 17c, so as to move forward and upward in the main direction of movement, to follow a parabolic trajectory. The chips then arrive on an additional lower tilting ramp 6, this ramp being strongly inclined at its toothed end 4 and practically horizontal at its other end.

 The stones are collected at the bottom of the tilting ramps 5a, 5b, 5e and are not driven upwards by the air blower from the nozzles 17a, 17b, 17c. When the stones leave the tilting ramps 5a, 5b, 5c these stones fall down and therefore separate immediately from the chips. The stones thus arrive on the inclined part of the tilting ramp 6 which, due to its inclination, cannot drive the stones forward until an outlet opening 9. The movement of the stones, on the contrary, follows a horizontal trajectory directed towards the rear, so that these stones fall on the plate 14.

The shavings leaving the three ramps 5a, 5b, 5e describe different parabolic trajectories and fall in different places on the lower tilting ramp 6. The heaviest shavings bake the tilting ramps 5a, 5b, 5th, fall respectively in 15th, 1-, b, 15c. On the contrary, the lightest shavings fall in 16a, 16b, ltc respectively
The different chip fractions of the tilting ramps 5a, 5b, 5c thus fall on the lower tilting ramp 6, mixing homogeneously.

The operating mode of the tilting ramps contributes to mixing together the different fractions of chips in case a separation between these fractions has occurred during the transport by air flow between the tilting ramps 5 and the tilting ramp 6. The shavings are thus perfectly mixed when they leave the lower tilting ramp 6 and fall through the outlet 9
The stones and other heavy particles fall on the plate 14 and advance in the direction of the outlet orifice 9 as a result of the vibratory movement of the plate 14, this movement describing the same trajectory as the casing 1.

When the heaviest particles arrive in the part of the plate closest to the outlet orifice 9, these particles fall on a strongly inclined part 19 of the casing 1 and come out by sliding through an outlet orifice 13
The stones and other heavy particles, before leaving the plate 14, pass through a stream of air 18 coming from a nozzle 11. This stream of air entrains downwards, on the plate 14, the chip particles which can by example having been entrained between heavy particles. The chip particles located between the heavy particles are entrained by the air stream 18 and describe a parabolic path to then fall at 12. These chip particles are then entrained towards the outlet opening 9 by the vibrations of the housing 1.

 In the upper front part of the casing 1, above the outlet opening 9, there is a suction socket 20 connected by a suction duct 22 to the suction inlet of a fan 21. The ejection nozzles 7a, 7b, 7c, and 11 are branched, by a conduit 23, on the pressure side of the fan 21. The air from the air streams 7a, 7b, 7c and 18, is directed through the casing 1 so as to pass above and below the lower tilting ramp 6 to reach the suction opening 20. From there, the air returns to the nozzles 7a, 7b, 7c and 11 by the fan 21.

The air flow circulating between the nozzles 7a, 7b, 7c, and the suction opening 20, to pass over the tilting ramp 6, is slightly turbulent and thus contributes to the mixing of the possible fractions of shavings which may have be formed during transport by an air stream of these chips between the tilting ramps 5a, 5b, 5c and the lower tilting ramp 6.

In the embodiment described here, the separator comprises three tilting ramps 5. The number of these ramps 5 can however be increased or reduced to a single ramp, the number of ejection nozzles 17 then having to be increased or reduced correspondingly
In the separator described above, this one is capable of effecting the separation between the chips and heavier fractions while maintaining the homogeneity of the mixture between the different sizes of chip fractions.

 The second preferred embodiment of the invention, described below, is particularly advantageous for separating, for example, heavy fractions from what are called biological masses. The term biological masses Biomass must be considered as relating to forest products to be thrown away such as cut branches, stumps, etc. In this application of the invention, the sizes and weights of the materials to be sorted can vary considerably.

 FIG. 3 represents an apparatus 30 intended for separating the earth, stones, etc. from biomass or other materials. This device comprises a vibrating conveyor divided into two sections 31, 32. The first section is identical to the first conveyor described above, and the second section is identical to the additional conveyor orally described above. The first section 31 goes from an inlet end 32 to an outlet end comprising a gap 33 intended for separation by air blower. The second section 32 goes from this interval 33 to the outlet end 34 of the section 32. The bottom 35 of the second section 32 is parallel to the bottom 36 of the first section. The bottom 35 of the second section 32 is located at a lower level than the bottom 36 of the first section.

 We can choose by way of example, a difference in levels of 50 mm for a width a of 100 mm from the interval 33.

 The second section 32 is provided, at its inlet end 51, with an inclined part in the form of an inclined plane 37, the length of which can be of the same order as the width of the gap 33. FIG. 3 only shows a schematic side view of the device.

However, the tilting ramp 31, 32 has a large width, of the order of 1 m for example when its length is of the order of 5 m. The interval 33, like the inclined plane 37 extends over the entire width of the tilting ramp.

 A drive mechanism of known type, consisting of an eccentric mechanism 38 and suspension uprights 39, 40, 41, supports and drives the tilting ramp 31, 32 in a movement such as that indicated above.

As it is of known type; the drive mechanism below will not be described here.

 To separate, in a first phase, the sand or the earth from the biomass, these materials are introduced at the inlet end 32 of the tilting ramp 32 causing them to fall onto a screen plate 42.

 At the interval 33 is associated an air blower nozzle 43 capable of directing an air flow forward and upward, as indicated by the arrow 44, so as to thereby direct the air flow for that it passes above the inclined plane 37. The air nozzle 43 is connected to a fan (not shown) by a pipe 45.

 The operation of the apparatus described in Figure 3 is as follows.

The biomass load is introduced onto the screen plate 42 so that the sand or the earth falls through the screen and then passes under the tilting ramp 31. The movement of the tilting ramp then advances the biomass towards of the interval 33, so that the heavy fractions such as the stones gather at the bottom of the tilting ramp. In the interval 33 reigns a violent current of air directed upwards. The inclined plane 37 is inclined, with respect to the horizontal plane, by an angle such that the materials placed on it are driven backwards by a tilting movement such as that indicated by the arrow 46, The violent flow of air blows light fractions over a large area, in the direction of travel, towards the second section 32. The stones and the like are drawn backwards on the inclined plane 37, despite the draft. This air flow is regulated, however, so that the branches, stumps and the like constituting in themselves heavy fractions, are entrained, by the air blower, towards the top of the inclined plane 37, that is to say in arrow direction 47
The intensity of the air flow and / or the angle of the inclined plane with respect to the horizontal, are adjusted according to the material to be treated and the fractions to be separated.

As a result, in a preferred embodiment, the inclined plane 37 is rotatably mounted at the point of its transition with the bottom 35 of the second section 32, and can be locked in different angular positions relative to the bottom 35 of the second section 32, thanks to a conventional type adjustment device 48 constituted for example by a key cooperating with one or more holes 49 drilled in a fixed disc 50 (see FIG. 5)
In some cases it may also be advantageous to be able to vary the width of the interval 33
In another embodiment, the assembly of the apparatus 30 is placed so that the bottom 36 35 of the tilting ramp 31, 32 forms an angle v of the order of two to ten degrees, and preferably 7 degrees, with the horizontal plane. This arrangement makes it possible to make the material suitably compact and suitably divided during its transport on the tilting ramp. The angle v depends of course on the material to be treated.

In the treatment of biomass, it is desired to prevent the branches and stumps of relatively short length from falling into the interval 33 when they are brought above these intervals in a position transverse to the direction of transport. For this reason, in a further preferred embodiment of the invention, a number of support strips 48 are suitably spaced from each other above the gap 33 (see Figure i). The spacing of these support strips 48 is preferably equal to or greater than the width a of the interval 33
In the treatment of biomass, the support strips 48 preferably have a height such that their upper edge clearly protrudes above the bottom 36 of the tilting ramp 31. These strips 48 thus guide the material so that the main longitudinal axis parts of the material coincide with the direction of advancement.

 In this way the separation by blower of the biomass makes it possible to obtain a homogeneous mixture in the second section 32, after separation of the stones and the like.

 In a preferred embodiment, the section of the tilting ramp 31, 32 is for example profiled as indicated in FIG. 6. Such a design makes it possible to obtain a greater contact surface between the material and the tilting ramp, which makes it possible to increase the transport capacity.

 In different possible embodiments, the first section 31 and the second section 32 of the tilting ramp of FIG. 3 can for example be separated from one another and driven by common or separate equipment. In addition, the first section of the tilting ramp may consist of several tilting ramps placed one above the other. The tilting ramp 31, 32 can thus be produced in various suitable ways.

 In the embodiment of Figure 1, the tilting ramps 5a, 5b, 5c can be made separately, and the tilting ramp 6 can be placed at a higher level. On the other hand, the ventilation system does not necessarily have to be a closed system.

Claims (6)

PEVENDICATTONS  1- Blower particle separator intended to separate the heaviest fraction, constituted for example by stones, of a mixture of lighter particles of different properties, constituted for example by shavings, this separator comprising a conveyor (31, 5a, 5b, 5c) and a fan or any other similar means provided with an air blower nozzle (43, 17a, 17b, 17cj placed at the outlet end of the conveyor and capable of producing a stream of air inclined towards up and forward in the direction of advancement of the conveyor (31, Sa, 5b, 5c), separator characterized in that the conveyor (31, 5a, 5b, 5c) is of the vibrating conveyor type at the bottom of which the fraction of heavy particles accumulates, in that an additional vibrating conveyor (32, 6) is placed, in the direction of advance, after the exit end of the conveyor (31, 5a, 5b, 5c ) and at a lower level than this, so as to cooperate with it, this additional conveyor (32, 6) being provided with its outlet end (51, 4) of an upwardly inclined part (37) transforming into a part parallel to the main direction of the conveyor (32, 6), this inclined part (37) being arranged, with respect to the exit end of the first conveyor (31, 5a, 5b, 5c), so that the heavy fraction of the particles falls on this part (37) carrying them downwards.  2- Separator according to claim 1, characterized in that the additional conveyor (32) cooperates following the first conveyor (31), and in that an interval (33) is formed between the outlet end of the first conveyor (31) and the inclined part (37).  3- Separator according to any one of claims 1 and 2, characterized in that the additional conveyor (32, 6) is independent of the first conveyor (31, 5a, 5b, 5c).  4- Separator according to any one of claims 1 to 3, characterized in that the inclined part (37) comprises an inclined plane mounted in rotation relative to the bottom (35) of the additional conveyor (32) and being adjustable in different angular positions relative to this bottom (35).  5- Separator according to any one of claims 1 to 5, characterized in that the first conveyor consists of two or more conveyors (5a, 5b, Dc) placed one above the other; in that an air blower nozzle (7a, 7b, 7c) is placed at each outlet end of the conveyors (5a, 5b, 5e); and in that the additional conveyor (6) is placed at a lower level than the lowest of the first conveyors (5a, 5b, 5c).  7- Separator according to any one of claims 1 to 6, characterized in that the conveyors are enclosed in a housing (1) connected to a suction duct (20) placed in a part of this housing lying obliquely, by relative to the main drive direction, above the inclined part, this suction duct being connected to the fan to eject the sucked air, by the blower nozzle.