FR2580684A1 - Continuous prodn. of glued wadding of long fibres, such as wood fibres - incorporates a de-aggregation and aeration stage before gluing - Google Patents

Abstract

In the first stage, a wadding of fibres is produced with the compactness required. Wadding then passes through a zone (43) comprising a vertical chamber (44) for the de-aggregation and aeration of the wadding, and an intermediate zone (46), where glue is sprayed in by means of injectors (53). Then, a densification chimney (51) with beating sides (54, 55) where the initial compactness of the wadding, is recovered. Wadding is then passed through press (65) having compression cylinder (66,67). ADVANTAGE - Allows good mixing and repartition of the fibres and uniform coating of the fibres by the glue.

Description

 The subject of the invention is a method and a device used for the continuous manufacture of a homogeneously glued mattress with a view to its transformation into parts, from thin and long fibers, or from similar filaments of any material. and in particular in wood previously reduced into filaments.

 It has been known for a long time that it is possible to produce more or less thick pieces which can be used for various purposes, from fibers to which an appropriate adhesive is added and which is then compressed to the desired final thickness under conditions favorable to hardening of the glue.

 This apparently simple manufacturing has a difficulty due to two partly contradictory requirements which are one that the fibers must be tangled and hooked together as much as possible, the other that the fibers must be well coated with glue, each , over their entire surface. Poor tangling of the fibers or poor distribution of the glue results in a final panel which looks good but which tends to disintegrate prematurely when it is used.

 The merit of the invention is to have understood that the conventional measures considered to be the most favorable to the desired result are not as much as has been admitted so far. For example, in document FR-A2 332 858, it is mentioned as a characteristic of the process described therein that the drying, conveying, sizing or coating of binder, the division into individual metered volumes must be done in succession. without modification of the initial degree of expansion of the mass of fibers.

 The process of the invention is clearly distinguished in this sense that, first a fiber mat is produced having a determined initial degree of compactness which is suitable for the manufacture of the desired panels, this mattress is aired and decompressed, projects suitable glue or binder into the decompressed volume of the fibers, the mattress is then reformed after gluing the mat substantially to its initial compactness, the glued mattress is compressed in a manner known per se and it is cut to obtain the desired panels.

 A device according to the invention comprises a stage for forming a mattress with a determined degree of initial compactness from a continuous supply of dry fibers, a stage for ventilating, sizing and reforming the mattress at said degree compactness, comprising in vertical direction a vertical aeration chamber equipped with rollers with disaggregation and aeration spikes, an intermediate glue projection zone where glue injectors are installed peripherally, a vertical chimney converging from the top to the bottom of densification to substantially reform the initial degree of compactness.

 In a complete installation supposed to receive fibers or previously dried wood filaments directly, there is, according to the invention, a storage volume where the fibers are accumulated until complete filling, means for controlled extraction of the fibers from this storage volume, for the supply of the above-mentioned stage of formation of a continuous mattress of fibers at a determined degree of compactness. This stage comprises a chamber, having a lower entrance, where a detector is installed fiber inlet, a vertically inclined conveyor belt having an upper rising strand and a lower descending strand; a clipping belt is installed at the top of this conveyor belt on the side of its rising upper strand; a vertical channel descends from the top of this conveyor belt with a hinged wall and a lower outlet opening equipped with flow control cylinders, then at least one conveyor belt receives the mattress and leads it to the top of the vertical chamber. aeration. Preferably, this chamber has an upper feed opening equipped with flow control cylinders braking the free fall of the fibers inside said chamber.

We will now give, without limiting intent and without excluding any variant, a description of a complete device according to the invention. Reference is made to the accompanying drawings in which:
FIG. 1 shows a first, extreme part, where the storage volume is located,
FIG. 2 shows a second, intermediate part, where the stage for forming the mattress is located,
- Your Figure 3 shows a third part, extreme, where is the stage of ventilation, gluing, reforming the mattress and making parts, for example panels, of a continuous device which actually consists by the succession of the three parties represented separately.

 FIG. 1 shows a storage volume 1 consisting of an enclosure having an upper opening 2 through which fibers 3 arrive which have just undergone drying after their manufacture. Under the opening 2 extends over a large part of the length of the enclosure -1 an endless conveyor 4 open to crossbars 5 whose lower strand moves, as indicated by an arrow F1, to regularize the level of the fibers falling through. At the bottom of an end wall is a lower outlet opening 6.

The bottom of this enclosure 1 is constituted by a first horizontal carpet 7 followed by a second carpet 8 inclined upwards.

The upper strands of these two belts 7,8 also circulate towards the outlet opening 6. Near the end wall 9 at the bottom of which this opening 6 is installed an extraction belt 10 having numerous transverse protuberances 11. The strand of this mat 10 which is closest to the end wall 9 descends towards the opening 6; the opposite strand located on the interior side rises. Therefore,
the fibers which are constantly directed, on the whole, towards the extraction conveyor 10 can only arrive at the opening 6 by taking the passage limited by the end wall 9 and the downward strand of the extraction conveyor 10.

The opposite end wall 12 is provided with a pallet 13 articulated around a horizontal axis. When the enclosure 1 is completely filled with fibers, this pallet 13 is pushed by the fibers and an alarm is triggered. There is also, in front of the extraction belt 10, a detector 14 for the presence of the fibers. This detector 14 switches on the bottom belts 7,8 when the extraction mat 10 is no longer supplied with enough fibers.

 Under your outlet 6 are at least one horizontal conveyor 15 which arrives, in FIG. 2, at the entrance to a stage designated by the general reference 16 for forming a continuous mattress of fibers at a chosen compactness.

In this stage a chamber 17 has a lower inlet 18 in an end wall 19 and a lower outlet 20 in the opposite end wall 21. At the inlet 18 there is a pallet 22 articulated around an upper horizontal axis; this palmette 22 controls the arrival of the fibers at the entrance 18. After this there is a first lower belt 23 fed by the preceding belt 15, slightly inclined horizontally, upwards, to supply a dosing belt 24 strongly inclined upwards, having numerous transverse protrusions 25. This dosing belt 25 has a rising strand 26 close to the first lower belt 23; the opposite strand 27 descends while being spaced apart by a small gap 28 of an incLined partition 29 which is parallel to it.

 At the top of the dosing belt 24 is installed, on the side and at the terminal end of its rising strand 26, a clipping belt 30 which also has numerous transverse protuberances. This mat 30 is arranged horizontally, at a position adjustable in distance with respect to the rising strand 26; it has a lower strand 31 which moves away from the rising strand 26, as indicated by an arrow F2. Consequently, when the volume of the fibers entrained by the rising strand 26 becomes too large at the top of the metering belt 24, the clipping belt 30 removes the excess and rejects it downwards.

On the opposite side, that of the descending strand 27, at the beginning of this strand is mounted a transverse roller 32 with spikes, horizontal, arranged to be under the sheet of fibers which falls from the top of the dosing belt 24. This roller 32 is offset towards the dosing belt 24 with respect to the entry of a downward vertical channel 33 into which arrives the sheet of fibers which falls from the dosing belt 24 while being guided by an inclined partition 34. But if there is an excess quantity of fibers at the entrance to channel 33, the roller 32 which rotates clockwise when looking at FIG. 2,
Directs it in the interval 28 where it descends to the bottom of the dosing belt 24 to be taken up there.

 The downward channel 33 has a rectangular cross section bounded by a main wall 34 which is adjustable in position to allow adjustment of the thickness or internal width; the opposite main wall 35 is a wall articulated at its upper part to be swinging, at a low amplitude, under the effect of a link 35 driven by a crank 36. The greatest displacements during the beats are executed by its lower end.

 This channel 33 ends with a lower opening 37 under which are mounted two successive pairs 38, 39 of flow control cylinders. The cylinders of the first pair 38 are spaced apart by a distance less than the width or thickness of the downward channel 33 and the cylinders of the second pair 39 are further tightened. This second pair 39 is located at the outlet 20 from the chamber 17. Thanks to the members described above and their combined action, it comes out through the outlet 20 a mat of fibers with a predetermined initial compactness, substantially constant, of a thickness also constant. This mattress is guided after exit 20 by a curved plate 40 which leads it onto a discharge conveyor 41. The latter feeds an inclined lifting conveyor 42 which rises, as can be seen with reference to FIG. 3, to drive the mattress formed on the next floor, designated by the general reference 43, for ventilation, sizing and reforming the mattress after sizing.

 The mat 42 arrives at the top of a vertical upper chamber 44 which has a constant rectangular cross section from an upper entry opening 45 to an intermediate zone 46 of projection of glue or binder.

 Above the terminal end of the lifting belt 42 is installed a first regulating roller 47, rotating counterclockwise, at a position where it is balanced by a counterweight 48. The entry 45 is wide enough to be placed partly under the top of the lifting belt 42 and to contain part of the surface of a second regulating roller 49 rotating counterclockwise, in a position where it is balanced by a counterweight 50. These two rollers 47,49 are rotated by a motor reducer group with speed variator. These rollers 47, 49 stop the free fall of the fiber mat through the opening 45 and, by turning as they do, they drive the fibers into the inlet 45 at a regular and controlled rate.

 Just below the inlet 45, the chamber 44 contains at least two disaggregating cylinders 51, 52 rotating in opposite directions, with surfaces furnished with spikes, which disperse the fibers throughout the chamber section 44. It will be noted that this section has a width which is approximately 3 times greater than that of the channel 33. The fiber mat is therefore notably decompressed, ventilated, before arriving at the intermediate zone 46. In the latter are distributed peripherally injectors 53 of glue or binder. In practice, three injectors on each main side of the cross section are sufficient; they are inclined upwards, with an inclination of 30 to 45 ". Thus, the fibers having been decompressed and having separated from each other during their free descent inside the chamber 44 between the disintegrating cylinders 51, 52 and the intermediate zone 46, they are coated with glue over their entire surface under the most favorable conditions.

 After the intermediate zone 46, the rectangular cross section of the chamber 44 gradually decreases thanks to the inclined arrangement towards one of the two opposite main walls 54, 55; this part constitutes a densification chimney, designated by the general reference 56, where the initial compactness of the mattress is reformed. The two inclined walls 54, 55 terminate by limiting between them a passage 57 which is substantially identical in dimensions to the lower opening 37 and which is followed by two successive pairs 58, 59 of flow control cylinders. Thus, the mattress is reformed substantially to the same compactness, but the fibers are now coated with glue or binder.

 In addition, to facilitate the descent and progressive tightening of the glued fibers, the two opposite main walls 54, 55 are swinging like the wall 35 of the channel 33. For this purpose, each wall 54, 55 is connected by a corresponding link 60, 61 to a crank; the two cranks are offset by 1800 so that the two walls move apart and approach symmetrically.

 Then, a curved plate 62 directs the mattress on a discharge belt 63 above which is placed a roller 64 with spikes which rotates in the opposite direction to the direction of advancement of the mattress. This roller 64 is at a determined adjustable distance from the evacuation belt 63: it has an equalizing role in repelling the localized surpluses of fibers which may exist. The belt 63 feeds a compression press 65 which has one and preferably two pairs 66,67 of calender cylinders. These cylinders can each have any suitable length; in each pair 66,67, the glued mattress is subjected between the cylinders to a compressive force of 2000 kN. Then, a sawing station 68 cuts the mattress into individual sections which are evacuated by a belt 69.

Claims (11)

 1. Method for the manufacture of a glued mattress from Long fibers joined by a ball, according to which a fiber mattress is first produced having a determined initial degree of compactness suitable for the manufacture of desired parts, and subsequently coated these fibers with adhesive and they are compressed, characterized in that the fiber mattress is decompressed and aerated before coating the fibers with adhesive and after sizing the mattress is reformed substantially to the initial degree of compactness before compressing it.  2. Device for manufacturing a glued mattress from Long fibers joined by an adhesive, comprising a stage (16) for forming a mat of fibers with a determined initial compactness, sizing injectors (53), a cylinder press (65) (66, 67), characterized in that it further comprises, between said stage (16) and said press (65), a stage (43) for disaggregating and ventilating the mattress, for gluing and reformation of the mattress substantially at its initial compactness, this stage having an intermediate zone (46) where said glue injectors (53) are installed.  3. Device according to claim 2 characterized in that it comprises in vertical direction from top to bottom an upper chamber (44) with rectangular cross section for disaggregation and aeration of the fiber mat, the intermediate zone (46) d 'sizing, a densification chimney (56) with vertical cross section of progressively decreasing size or thickness to a lower opening (57) followed by at least one pair of cylinders (57, 58) of flow control.  4. Device according to claim 3 wherein The stage (16) for forming the fiber mat at a determined initial compactness has an outlet opening (37), characterized in that the lower opening (57) of the de-ensification chimney (56) has dimensions substantially equal to those of said outlet opening (37).  5. Device according to claim 3 in which the stage (16) for forming the fiber mat with a determined initial compactness has an outlet opening (37), characterized in that said upper chamber (44) has a cross section of which the width or thickness is approximately three times that of said outlet opening (37).  6. Device according to claim 3 characterized in that the upper chamber (44) has an upper opening (45) above which is mounted at least in regulating roller (49) with adjustable speed of braking braking the free fall of fibers through said upper opening (45).  7. Device according to claim 3 characterized in that the upper chamber (44) has an upper opening (45) below which are mounted at least two disaggregating cylinders (51,52) rotating in opposite directions.  8. Device according to claim 3 characterized in that the densification chimney (56) has two opposite main walls articulated at their upper part and swinging continuously.  9. Device according to claim 2 characterized in that the stage (16) for forming a fiber mat with a determined initial compactness comprises a vertical descending channel (33), of rectangular cross section, limited by a main wall ( 35) articulated at its upper part to be continuously beating, this channel (33) ending in a lower opening (37) under which there is at least one pair of cylinders (38,39) for flow control.  10. Device according to claims 3 and 9 characterized in that under the two outlet openings (37,57) there are two superposed pairs (38,39 - 58,59) of flow control cylinders, the cylinders of the pair (39,59) the lower more being closer than the cylinders of the upper pair (38,59).  11. Device according to claim 2, characterized in that it further comprises a storage volume (1) having an end end wall (9) contiguous to a lower outlet opening (6), an extraction belt (10 ) being mounted parallel to this end wall (9) with its strand (11) closest to the latter moving from top to bottom in the direction of said lower opening (6).