EP1789614B1 - Scutching device - Google Patents

Abstract

The invention relates to a scutching device, comprising transport means for stems in a transport direction (X), essentially perpendicular to the orientation of the stems, with at least one gripping and driving means (60), for said stems and at least one breaker unit (30), comprising at least one pair of fluted superimposed breaker rollers (31-35). The invention is characterised in that said scutching device further comprises a fibre cleaning device, downstream of the breaking unit (30) and in a zone above said gripping and driving group (60), comprising means for projecting (42) downwards a fluid and/or particles in the direction of the stems by means of which the waste separated from the stems by the breaking unit (30) are removed from the stems which are held in said gripping and driving unit (60).

Description

The invention relates to the technique of scutching flax or any other cellulosic fiber that can be dyed, such as a bast fiber, such as hemp, kenaf, jute or ramie.

In known manner, the scutching operation, or shelling, is intended to mechanically treat, after retting, the flax stems to separate the fibers (or tow) from the other parts of the plant (the head, containing the straw and the sponge). seed, and the woody parts of the stem or shoots). These fibers are then combed to further remove shives and short fibers or tow, before clearing long fibers having the qualities required for their subsequent use, especially in spinning.

Classically, this scutch comprises firstly a step of égrainage during which a steel tooth comb will separate the capsule of the stem or straw, see for example DE 665,281 .

Then there is a grinding step followed by a turbining step.

Grinding refers to the step during which the cohesion of the rod is broken by grinding between pairs of rotating corrugated rollers arranged in meshing, and whose axes are parallel to the rods advancing in sheet, in order to break the lignin and allow the extraction of shives.

The turbining effects this separation between the fibers and the shackles by the shocks generated by means of steel blades movable in rotation along an axis perpendicular to the direction of the rods and which strike successively all the portions of the rods.

More particularly, the present invention relates to the improvement of the operation of extraction of shives, namely woody waste linseed, to allow an increase in the amount of this waste, namely a decrease in fiber loss.

Indeed, it is understood that the grinding operations and turbinage generate shocks and intense shear stresses on the stem of flax, these very violent operations are considered until now as necessary to remove the shingles, given the very important mechanical strength of flax fibers.

However, this method causes breaks in the long fibers, which generates the short fibers called tows, which must be separated from the intact long fibers, which reduces the extraction efficiency of long fibers. The latter reaches about 20% whereas the total amount of fibers contained in the stems is estimated at 30%.

It is therefore an object of the present invention to allow the separation between the shives and the fibers of the flax stems, while reducing the rate of rupture of the fibers, and this in order to keep at the end of scutching a maximum of long fibers.

• des moyens de transport des tiges selon une direction d'entraînement sensiblement perpendiculaire à l'orientation des tiges, qui comprennent au moins un ensemble de préhension et d'entraînement des dites tiges, et
• au moins une unité de broyage comprenant au moins une paire de rouleaux de broyage superposés cannelés.

For this purpose, the present invention provides a device for scutching flax or any other plant whose stem contains cellulosic fibers that can be separated by scutching, comprising, in the usual manner:

• means for transporting the rods in a driving direction substantially perpendicular to the orientation of the rods, which comprise at least one gripping and driving assembly of said rods, and
• at least one grinding unit comprising at least one pair of corrugated rollers.

Typically, the scutching device according to the present invention further comprises, downstream of the grinding unit and in an area above said gripping and driving assembly, a fiber cleaning unit comprising means downwardly projecting a fluid and / or particles in the direction of the rods, whereby the waste disconnected from the rods by the grinding unit are extracted from the rods which are retained in said gripping and driving assembly.

In this way, it is understood that by the presence of said fiber cleaning unit operating by projection, the fibers of the rods are cleaned by the fact that the shins which have been separated from the fibers during the preceding grinding step, are, thanks at this projection, "detached" and separated fibers to be driven by the flow of fluid and / or particles that is projected, and then are driven by Venturi effect or in a recovery system.

This solution also has the additional advantage of being simple to implement, and in particular compact.

Overall, thanks to the arrangement according to the present invention, it is possible to improve the extraction efficiency of the fibers of the flax stems in a simple and effective manner.

The fluid may be a liquid or a gas and the particles will be in particular abrasive particles such as sand or fine shot.

Preferably, said projection means comprise at least one nozzle for blowing air under high pressure, the air being sent at a pressure preferably of between 1 and 10 bar, ie between 100,000 and 1,000,000 Pa, and advantageously between 4 and 7 bars, ie between 400,000 and 700,000 Pa.

Preferably, said projection means comprise at least one projection nozzle of sand, shot, seeds and / or other particles.

According to a preferred arrangement, said projection means are located at least on either side of said gripping and driving assembly, and this in order to clean the rods over their entire length, except the zone of the rod situated in said assembly gripping and training.

According to another preferred arrangement, said scutching device comprises at least three successive grinding units and at least three gripping and driving assemblies, each grinding unit comprising at least three pairs of grinding rollers arranged from upstream to downstream and each grinding unit being associated with one of said gripping and driving assemblies, and said successive gripping and driving assemblies have laterally offset driving directions between a gripping and driving assembly and the following.

This arrangement, which provides for a succession of several scutching units, each comprising a grinding unit and a cleaning unit located downstream, makes it possible to carry out the crushing and cleaning steps in succession successively and several times, so that the waste is disconnected from the fibers by a grinding step are removed as the fibers by the subsequent cleaning step before the rods are again subjected to a grinding step, etc .; and this several time in order to achieve fully cleaned fibers of the shives, while maintaining a maximum of intact fibers, that is to say unbroken.

According to a preferred embodiment, the size of the grooves of the grinding rollers decreases from upstream to downstream along the scutching device.

In this way, by reducing as the progress of the rods in the scutching device the size of the grooves of the grinding rollers, grinding is also carried out more and more finely, which allows to take off the shoots at deeper of the stem. This gradual decrease in the size of the flutes can be achieved in different ways.

Preferably, from one milling unit to the next, each milling unit comprises rollers whose groove size is smaller than in the milling unit which precedes it, according to the drive and upstream direction. downstream. This arrangement can be achieved with, for each of said grinding units, rollers whose grooves are substantially the same size in a grinding unit considered, but a size smaller than that of the grooves of the rollers of the preceding grinding unit. This arrangement can also be obtained with grinding units which comprise rollers having, for the same grinding unit, different spline sizes, possibly with the same size between the last roll of the upstream grinding unit and the first roll of the grinding unit. downstream milling unit that succeeds him.

According to another advantageous arrangement, the upper and lower rollers of each grinding unit are rotated in synchronized manner, the grooves of the upper roll coming to mesh, without contact, between two grooves of the lower roll.

In this way, the grinding of the rods is carried out without the risk of breaking the rods at a location corresponding to a contact between the grooves, which would contribute to break fibers along their length, which would be detrimental in terms of output fiber yield .

In addition to this arrangement, preferably, the splines are shaped so that when a groove of the upper roll meshes between two grooves of the lower roll, there is a substantially constant gap between said groove of the upper roll and said two grooves of the lower roll.

Thus, it is understood that a constant maximum stress is exerted on the fibers for a given pair of grinding rollers and, preferably, also for all pairs of grinding rolls.

According to another preferred arrangement, said gripping and driving assembly comprises a pair of endless moving belts, flat and toothed, coming into contact with one another to clamp a section of the rod to train during the movement of the belts.

In this way, the retention of the rods is very simple, without exerting on them too great localized pressure at the location of the section of the rod clamped between the moving belts, as may be the case with the devices of the art. which use conveyor belts with a U-section.

• la figure 1 est une vue partielle en projection depuis l'un des côtés d'un dispositif de teillage de lin selon l'invention ;
• la figure 2 est une vue schématique de dessus du dispositif de teillage de lin de la figure 1, comprenant cinq unités de teillage décalées transversalement l'une après l'autre selon deux lignes parallèles ;
• la figure 3 une vue de côté d'une portion du dispositif de teillage de la figure 1, sous la forme de l'une des unités de teillage ;
• la figure 4 montre depuis le dessus la portion du dispositif de teillage visible sur la figure 3 ;
• la figure 5 est une vue partielle, en perspective simplifiée, de la portion du dispositif de teillage visible sur les figures 3 et 4, montrant le traitement des tiges de lin ;
• les figures 6A, 6B et 6C représentent chacune, en projection depuis le côté, une paire de rouleaux de broyage munie de cannelures, chaque paire de rouleaux de broyage ayant des cannelures de taille différente ;
• les figures 7A, 7B et 7C représentent de manière agrandie l'engrènement sans contact entre les deux rouleaux des paires respectivement illustrées sur les figures 6A, 6B et 6C ;
• la figure 8 montre, en projection depuis l'extrémité aval, une unité de teillage et en particulier l'unité de nettoyage des fibres, et
• la figure 9 est une vue partielle agrandie de l'unité de nettoyage des fibres de la figure 8.

Other advantages and characteristics of the invention will become apparent on reading the following description given by way of example and with reference to the appended drawings in which:

• the figure 1 is a partial view in projection from one of the sides of a linen scutch device according to the invention;
• the figure 2 is a schematic top view of the flax scutching device of the figure 1 , comprising five scribing units transversely offset one after the other along two parallel lines;
• the figure 3 a side view of a portion of the scutching device of the figure 1 in the form of one of the scutching units;
• the figure 4 shows from above the portion of the scutching device visible on the figure 3 ;
• the figure 5 is a partial view, in simplified perspective, of the portion of the scutching device visible on the figures 3 and 4 , showing the treatment of flax stems;
• the FIGS. 6A, 6B and 6C are each projecting from the side a pair of grinding rollers provided with splines, each pair of grinding rollers having splines of different size;
• the Figures 7A, 7B and 7C represent magnetically contactless meshing between the two rolls of the pairs respectively illustrated on the FIGS. 6A, 6B and 6C ;
• the figure 8 shows, in projection from the downstream end, a scutching unit and in particular the fiber cleaning unit, and
• the figure 9 is an enlarged partial view of the fiber cleaning unit of the figure 8 .

On the Figures 1 and 2 is shown an embodiment of a linen scutch device 10 according to the present invention. In the case of this particular embodiment shown, the linen scutching device 10 comprises, in the longitudinal direction X, five linseed scutching units 11, 12, 13, 14 and 15.

These five flaxseed units 11 to 15 operate on an identical principle represented on the figure 5 , each of these scutching units 11 to 15 having the same visible structure on the figures 3 and 4 which will be described in more detail below.

On all of these Figures 1 to 5 , the direction of advance of the flax stems is from the left to the right forming upstream and downstream respectively.

• une zone d'entrée 20,
• une unité de broyage 30,
• une unité de nettoyage de fibres 40, et
• une zone de sortie 50.

Each of the scutching units 11 to 15 has a generally identical structure formed of four main parts comprising from upstream to downstream respectively:

• an entrance area 20,
• a grinding unit 30,
• a fiber cleaning unit 40, and
• an exit zone 50.

As can be seen on the Figures 1 and 2 , the exit zone 50 of the scutching unit 11 is situated, in the longitudinal direction X, of the entry zone 20 of the scutching unit 12 which is located downstream of the preceding scutching unit 11 .

Indeed, the scutching units 11, 12, 13, 14 and 15 are successively arranged one after the other in the longitudinal direction X while being offset transversely in the Y direction with respect to the neighboring scutching unit. that all the sections of the stem of the plant are treated as will be explained below.

Each scraping unit 11 to 15 is traversed by a drive system 60 with an endless double belt 61 and 62.

As it appears on the figure 3 the two endless belts 61 and 62 are notched flat belts forming a closed loop around two pulleys 63 (65) and 64 (66). The two loops delimited by the belts 61 and 62 are arranged one above the other so as to wedge between them a web 100 of linen stems (see figure 4 ) which remains sandwiched between the portions of the belts 61 and 62 which are in close contact with one another and which form a gripping zone 60a.

More specifically, the flax rods are held by (clamped between) the belts 61 and 62 which have faces facing in relief in the form of a notch.

As we see more precisely on the figure 2 between two successive scutching units (for example the units 11 and 12), the exit zone 50 of the first scutching unit 11 being disposed on the side (along the longitudinal axis X) of the input zone 20 next scutching unit 12, is provided by a transverse shift (in the Y direction) of the drive system of the two successive scutching units having the two belts 61 and 62, a continuity of transport of the linen web 100 between the a drive system 60 from the scutching unit 11 to the drive system 60 of the following scutching unit 12 which hold respectively the flax stems at two adjacent sections of these stems, which sections are located in the central part of the linen stalk as can be seen on the figure 4 on which is represented partially a sheet 100 of flax stems.

The inlet zone 20 of each scutching unit 11 to 15 has the double-belt drive system 61 and 62 shown above, so that this entry zone 20 only ensures the advancement of the ply 100 of the stems. linen.

If we refer to figures 3 and 4 the grinding unit 30 of each scoop unit 11 to 15 is provided with five pairs 31 to 35 of superposed fluted grinding rolls.

More specifically, referring to the first pair 31 of grinding rollers, it comprises an upper grinding roll 31a and a lower grinding roll 31b whose axes are arranged respectively above and below the gripping zone 60a of the timing belts 61 and 62, each of these rollers 31a and 31b being itself (see FIG. figure 4 ) formed of a section 31b1 located on one side of the gripping zone 60a and a section 31b2 located on the other side of the gripping zone 60a.

In this way, it is understood that the processing of the linen web 100 is carried out simultaneously to the right and left of the drive system 60 in order to carry out the grinding, at each pair of grinding rollers 31 to 35 along the entire length of the flax stems, with the exception of the section of the flax stems which is held between the straps 61 and 62.

It is therefore understood that at each scutching unit 11 to 15, the sheet 100 of the flax stems passes successively in several (in this case five) pairs of grinding rollers 31 to 35 which perform the crushing and folding woody parts of the flax stalk (or shives) in order to separate them from the fibers that one wishes to isolate and keep in the least altered way possible.

In practice, during this grinding treatment, as it appears on the figure 5 , the web 100 of linseed initially forming a fairly coherent set of rods parallel to each other, successively becomes more flexible so that the linseed stems, as and when they advance in each pair of grinding rollers 31, 32, 33 ..., relax and hang on both sides of the gripping zone 60a. Therefore, the central section of each rod is held between the belts 61 and 62 while the ends of the rods are located further back and are still locked between the grinding rollers. The treatment of the central portion of the rods being effected, on either side of the belts 61 and 62, at the rate of advance of the belts 61 and 62, while the ends of the rods being free, they follow this treatment slightly backwards. (upstream in the longitudinal direction X) of the central part of the rod.

On the figure 5 only three pairs 31 to 33 of grinding rolls are shown for the grinding unit 30 while the Figures 1 to 4 illustrate scutch units 11 to 15 which each have five pairs 31 to 35 of grinding rolls.

Thus, generally according to the present invention, each scutching unit may comprise a number of pairs of grinding rolls that are identical or different from each other, the number of pairs of grinding rolls of each scutching unit may vary from three to five (or more) pairs of grinding rollers.

Conventionally, the pairs of grinding rollers used for scutching flax are rolls with teeth or gear splines coming into contact with one another, one of the two rollers of the lower and upper rollers being leading, the other being led.

To this known structure, pairs 31-35 of grinding rollers which intermesh without contact are preferred, as can be seen in the Figures 6A to 6C and 7A to 7C .

For example, if we consider Figure 6A there is shown a pair 36 of coarse-grained grinding rollers 36a whose profile is in the form of a broken arc or a clipped-head warhead. According to the particular feature of this preferential provision, as it appears on the Figures 6A to 6C and 7A to 7C , which respectively illustrate the intermeshing position of the pair of grinding rollers 36, 37 or 38, the upper roll grooves 36a (37a or 38a) are never in contact with the lower roll grooves 36a (37a or 38a).

The distance e at the meshing between the grooves of the upper milling roll and the lower milling mill is as much as possible substantially constant as is apparent from the Figures 7A to 7C .

On the Figures 6B and 7B is illustrated a pair 37 of medium-sized fluting rollers 37a which have another shape: the flutes 37a have a cross-sectional shape whose sides are slightly convex and slightly inclined towards the flute head .

On the Figures 6C and 7C a third type of grinding roll is presented: the pair 38 is composed of two small groove milling rolls 38a whose section has an M-shaped contour. Between two small grooves 38a, the grinding roll 38 has a W-shaped contour corresponding to a longitudinal groove (see FIG. Figure 7C ).

It will be noted that in all cases, the grinding rollers have, between their grooves 36a, 37a or 38a, a recess (a groove) of complementary shape to that of the grooves.

In order to achieve the synchronous rotation movement of the upper and lower rollers of all pairs of rollers 31 to 35 composing a scutching unit, for example the scutching unit 11 of the figure 3 a single motor 39 carries out the movement of the five pairs of grinding rollers 31 to 35 by means of a single transmission belt 39a. In addition, this transmission belt 39a itself constitutes the drive means of the two belts 61 and 62 of the drive system 60 for transporting the web 100 of the stems of linen.

In this way, it is understood that it ensures, for each scraping unit 11 to 15, a synchronous drive of all the grinding rollers and the gripping zone 60a for a regular and synchronous advance of the web 100 of rods flax at the same scutching unit 11 to 15.

According to a particular arrangement, in order to place the lower and upper rollers of a pair of grinding rollers in meshing, it is the lower roll which is moved upwards by means of a pneumatic jack which actuates an arm lever which makes it possible to adjust the pressurization of the jack and therefore the stress exerted on the lower roll when it is placed in the meshing position with the upper roll.

Thus, in the event of a problem (blockage or other), if the control of the pneumatic cylinder is faulty or is no longer activated, the lower rollers are then in their low position, which corresponds to a safety situation avoiding, for example, injuries. by pinching between the rollers of the same pair.

In order to be able to precisely adjust the spacing between each roller of a pair of upper and lower grinding rollers, an adjustable stop device associated with the assembly consisting of the pneumatic cylinder and the aforementioned lever arm is provided, for each pair of grinding rollers.

From the foregoing, it is understood that the realization of contactless meshing between the lower grinding rollers and upper pair avoids exerting shear forces along the flax fibers.

In addition, the actuation by pneumatic jack of the high position of the lower grinding roller of each pair of grinding rollers makes it possible to exert an adjustable and constant pressure on the linen ply 100, which makes it possible to compensate the extra thicknesses. during the advance of this sheet 100 of flax stems and this to avoid "stuffing" at a pair of grinding rollers.

Also, it should be noted that the linear running speed of the drive belts 61 and 62 is adjusted according to the linear speed of rotation of the pitch diameter of the crimping roll grooves to prevent fiber tearing or stalk displacement. the drive belts 61 and 62.

It is also understood that the drive belts 61 and 62 being flat belts, they clamp the stems of flax fibers flat, which minimizes the breaks of the fibers, and this in order to preserve the integrity of the fibers as much as possible their length.

This preferred embodiment of the grinding rollers with contact-less meshing is advantageously combined with a progressive reduction in the size of the grooves of the grinding rollers as the linseed rods advance in the scutching device. linen 10.

Three sizes of splines can be used, such as those shown on Figures 6A to 6C and 7A to 7C or more different sizes with intermediate sizes, either with identical shape or with different shapes. In the case of the choice of different shapes for the flutes, the larger flutes will preferentially have the shape of the flutes 36a of the flutes. Figures 6A and 7A , the flutes of medium size will preferentially have the shape of the grooves 37a of the Figures 6B and 7B and the grooves of smaller size will preferentially have the shape of the grooves 38a of the Figures 6C and 7C .

For each scutching unit it is possible to use grinding rollers having the same size of grooves or already several different sizes as one moves in longitudinal direction X, upstream downstream along the unit. of scutch considered.

Grinding rollers having different fluting sizes from one scutching unit to another may also be used or using for the last pair of grinding rolls of an upstream scutch unit a flute shape identical to that of the first pair of grinding rollers of the scutching unit placed directly downstream.

The fiber cleaning unit 40 is now described which is used according to an essential feature of the present invention. For this purpose, each unit of flaxseed 11 to 15 (see figures 1 and 4 ) has a fiber cleaning unit 40 disposed downstream of the grinding unit 30.

This fiber cleaning unit 40 is intended to separate the shives of the fibers with respect to shives that have not already fallen by themselves during the shredding treatment which has previously been carried out in the grinding unit 30 of the shredder. the same scutching unit 11 to 15.

To do this, each grinding unit comprises (see Figures 8 and 9 ) according to a preferred embodiment two nozzles 42 for blowing air under pressure arranged vertically above and on either side of the gripping zone 60a of the drive system 60, downstream of the grinding unit 30. The jet of high pressure air is sent under a pressure of between 1 and 10 bar (100,000 to 1,000,000 Pa) and preferably between 4 and 7 bar (between 400,000 and 700,000 Pa).

Alternatively or combined, this high-pressure air flow can contain high-speed percussionants such as sand, grit, seeds, pebbles, etc.

When only a jet of air under high pressure is used, preferably an air flow guide box 44 is used comprising (see FIG. Figures 8 and 9 ) side panels inclined downwardly towards a collecting funnel 46 at which a separate suction can be provided to increase the Venturi effect.

It is also expected to collect the snails upstream of the cleaning unit 40, namely under the grinding unit 30 and under the inlet zone 20 by means of a collection hopper 70 at the bottom of which is disposed a suction system with motor and auger.

Thanks to a scutching device in accordance with the various provisions presented in the description of the figures, it results in a scutching of the linseed stems making it possible to very significantly increase the yield of the long fibers by up to 25% and more, compared with the 20% obtained according to the prior art and 30% of fibers contained in the stems of flax.

It will be understood that this result makes it possible to very substantially improve the extraction efficiency of the flax fibers from the stems, and this in particular thanks to the means of projecting downwards a fluid and / or particles, which perform the extraction of waste liners, and in particular cleaning the rods by blowing air under pressure (and / or percussion) between each grinding step.

Claims (10)

1. A stripping device (10) for flax or for any other plant whose stalk contains cellulose-type fibres which are capable of being separated by stripping, and that includes:

   - means for transportation of the stalks in a direction of movement (X) that is approximatively perpendicular to the orientation of the stalks, which include at least one assembly for grasping and moving (60) the said stalks, and

   - at least one crushing unit (30) that includes at least one pair of fluted, superimposed crushing rollers (31-35),

   characterised in that it also includes, downstream of the crushing unit (30) and in a zone located above the said grasping and moving assembly (60), a unit for cleaning (40) the fibres with means for the projection (42) downwards of a fluid and / or of particles in the direction of the stalks, so that the waste materials separated from the stalks by the crushing unit (30) are extracted from the stalks that are retained in the said grasping and moving assembly (60).
2. A stripping device (10) according to claim 1, characterised in that the said means of projection include at least a nozzle (42) for blowing air at high pressure.
3. A stripping device (10) according to either of the previous claims, characterised in that the said means of projection include at least one nozzle for the projection of sand, shot, grains and / or other particles.
4. A stripping device (10) according to any of the previous claims, characterised in that the said means of projection are located at least on either side of the said grasping and moving assembly (60).
5. A stripping device (10) according to any of the previous claims, characterised in that it includes at least three successive crushing units (30) and at least three grasping and moving assemblies (60), with each crushing unit (30) including at least three pairs of crushing rollers (31, 32, 33) positioned from upstream to downstream and with each crushing unit (30) being associated with one of the said grasping and moving assemblies (60), and in that the said successive grasping and moving assemblies (60) have directions of movement that are laterally offset between one grasping and moving assembly (60) and the next.
6. A stripping device (10) according to claim 5, characterised in that the size of the fluting on the crushing rollers (31-35) reduces from upstream to downstream along the stripping device (10).
7. A stripping device (10) according to claim 5 or 6, characterised in that from one crushing unit (30) to the other, each crushing unit (30) includes crushing rollers (31-35) in which the size of the fluting is smaller than in the crushing unit (30) that precedes it, in the direction of movement (X) and from upstream to downstream.
8. A stripping device (10) according to any of the previous claims, characterised in that the upper (31b) and lower (31a) rollers of each crushing unit (30) are driven in rotation in a synchronised manner, with the fluting of the top roller (31b) meshing, without contact, between two flutes of the bottom roller (31a).
9. A stripping device (10) according to claim 8, characterised in that the flutes are shaped so that when a flute of the top roller (31b) meshes between two flutes of the bottom roller (31a), there exists an approximatively constant gap (e) between the said flute of the top roller (31b) and the said two flutes of the bottom roller (31a).
10. A stripping device (10) according to any of the previous claims, characterised in that the said grasping and moving assembly (60) includes a pair of endless, flat and serrated mobile belts (61, 62) that come into contact with each other so as to grip a section of the stalk in order to drive it along as the belts (61, 62) move.

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