Device for forming perforated carded-fiber webs

Abstract

Device for forming a web of non-woven material fibers, comprising a drum (10), at least one rotating comb (20) comprising a plurality of adapted teeth, said teeth being regularly distributed over an external surface (22) of the comb (20) characterized in that said at least one comb (20) is configured so as to form a web (30) having recesses, said at least one comb (20) thus comprising areas on its external surface (22) which cannot take material from the drum (10), the device further comprises a cleaning comb (40), adapted to recover the material present on the drum (10) downstream of said at least one comb (20).

Description

Technical Field

[0001] The present invention relates to the field of thermo-acoustic insulation of buildings, and more specifically the production of layers of non-woven material for the production of reflective or reflective thermal insulation. Prior art

[0002] Reflective insulators typically comprise two categories of products: the first category is that of "bubble" insulators, manufactured using plastics processes, and "multi-layer" insulators which alternate metallized films and separators composed either of cellular plastic foam or of textile fibers (natural or synthetic) forming a fiber mat. The present invention applies in particular to multi-layer insulators based on textile fibers.

[0003] Most often we see an alternation in the nature of separators within the same multi-layer product. However, the products of this same family of insulators are characterized by a common operating principle that is very different from other traditional insulators such as mineral fiber-based insulators or those based on synthetic resin such as polyurethane or extruded polystyrene.

[0004] This operating principle is to seek to block the propagation of heat by using both materials that are very poor heat conductors to create a structure capable of trapping still air cells within it, and by using both metallized or metallic films to cut off the propagation of heat by radiation and to protect the still air cells, formed by the separators, from parasitic external air infiltration.

[0005] Optimizing the thermal performance of these insulators largely involves optimizing the performance of the separators. The present invention thus aims to optimize separators based on synthetic or natural textile fibers.

[0006] Currently, in most products on the market, textile fiber-based separators have the following disadvantages.

[0007] The manufacture of the nonwoven is carried out independently of the assembly of the nonwoven in the final complex: the manufacturing process therefore contains a reworking operation; this reworking operation therefore requires that the nonwoven be easily handled, i.e. rollable, transportable and unrollable again,

[0008] For nonwovens to be easy to handle, their manufacture must be thermo-bonded, which allows the fibers to be bonded together and gives them sufficient mechanical resistance to stretching to withstand subsequent handling operations. In addition, bonding the fibers requires the use of an oven, which has significant consequences on energy consumption and environmental impact.

[0009] Furthermore, the most common synthetic or natural textile fibers in reflective insulation are generally fibers that are highly absorbent in the infrared range, and this absorption will significantly reduce the thermal performance of the separator by increasing thermal conductivity. Therefore, insulation is limited to thin fiber mats, with fairly low or moderate grammages, ranging from 40 g / m 2 < to 100 g / m 2 < .

[0010] It has been proposed to increase the thermal resistance of the separators R (R = e / λ) by reducing the thermal conductivity by perforating the non-woven layers and / or by increasing the thickness of the separators (weight > 100 gr / m 2 < ).

[0011] On the other hand, increasing the thermal resistance of the separators poses various problems; not only is the opening operation itself complex to implement, but this operation is even more complex as the density of the sails to be opened increases, which is the case in view of regulatory developments, which tend to impose large thicknesses and / or very low conductivity.

[0012] The present invention thus aims to respond to these problems.

[0013] WO 2010 / 032951 A2 discloses a method of forming a web of nonwoven material fibers. Statement of the invention

[0014] To this end, the present invention relates to a device for forming a sheet of non-woven material fibers, comprising: a rotating drum having an external face, adapted to be supplied with textile fibers and to distribute them on its external face, at least one rotating comber comprising a plurality of teeth adapted to take textile fibers present on the external face of the drum so as to form a sheet of material, said teeth being regularly distributed on an external surface of the comber characterized in that said at least one comber is configured so as to form a sheet having recesses, said at least one comber thus comprising areas on its external surface which cannot take material from the drum, the device further comprises a cleaning comber, adapted to recover the material present on the drum downstream of said at least one comber.

[0015] According to one example, the device comprises means for recovering the material removed by the cleaning comb, and for reintroducing said material to feed the drum.

[0016] According to one example, the areas of the outer surface of said at least one comb configured so as not to take material from the drum are formed by local destruction of teeth on the outer surface of said at least one comb and / or by filling of teeth on the outer surface of said at least one comb.

[0017] According to one example, said tooth sealing on the external surface of said at least one comb is formed by affixing a material cover so as to seal a volume between teeth of said at least one comb.

[0018] The present invention also relates to a method of forming a web of nonwoven material fibers using a card, wherein: one provides textile fibers, typically non-woven, a rotating drum is fed with the textile fibers, textile fibers are taken from the rotating drum with at least one rotary comber adapted to take the textile fibers from the drum, said rotary comber comprising a plurality of teeth adapted to take textile fibers present on the external face of the drum so as to form a sheet of material, said teeth being regularly distributed on an external surface of the comber, said comber being configured so as to have areas on its external surface which cannot take material from the drum, so that the sheet formed by said at least one comber has recesses the material remaining on the rotating drum is recovered downstream of said at least one rotary comber with a cleaning comber.

[0019] According to one example, following the recovery of the material remaining on the rotating drum downstream of said at least one rotating comber with a cleaning comber, said material is reinjected upstream of the material supply to the rotating drum.

[0020] The present invention further relates to a nonwoven material fiber web obtained by means of such a method. Brief description of the drawings

[0021] The invention and its advantages will be better understood upon reading the detailed description given below of different embodiments of the invention given as non-limiting examples. [ Fig. 1 ] There figure 1 shows a partial view of a device according to one aspect of the invention. Fig. 2 ] There figure 2 represents another partial view of a device according to one aspect of the invention. Fig. 3 ] There figure 3 represents another view of a device according to one aspect of the invention. Fig. 4 ] There figure 4 represents an example of a non-woven material sheet obtained with a device according to one aspect of the invention.

[0022] Throughout the figures, common elements are identified by identical numerical references. Description of the embodiments

[0023] We represent on the figures 1 à 3 a device for forming a web of non-woven material fibers.

[0024] The device as presented comprises a rotating drum 10 and one or more rotating combs 20.

[0025] The rotating drum 10 has the general shape of a cylinder of revolution. It has an external face 12, and is adapted to be fed with textile fibers and to distribute them on its external face 12. It is mounted rotating around a main axis ZZ.

[0026] The rotating drum 10 is supplied by a supply system not shown in the figures, configured to supply textile fibers so that the external face 12 of the rotating drum 10 is covered with textile fibers, typically in a uniform or substantially uniform manner.

[0027] The drum 10 is configured so as to standardize the distribution and orientation of the textile fibers present on its external face 12.

[0028] The device comprises at least one rotating comb 20.

[0029] The comber 20 is rotatable along an axis parallel to the main axis ZZ. The comber 20 typically has a generally cylindrical shape of revolution, with an external surface 22. The comber 20 comprises a plurality of teeth formed on its external surface 22, and adapted to take textile fibers present on the external face 12 of the drum 10 so as to form a sheet 30 of material. The comber 20 is commonly formed with teeth distributed regularly on the external surface 22 in order to obtain a uniform sheet of material, typically a sheet of non-woven material.

[0030] The invention proposes a distinct approach, and thus aims to modify the configuration of the teeth of the comber 20 so as to form one or more sheets of non-woven material having recesses, that is to say areas devoid of material.

[0031] The comber 20 thus comprises areas on its external surface 22 at which it cannot take material from the drum 10. Thus, the sheet of nonwoven material is formed upon exiting the combers 20 with recesses.

[0032] These areas of the comber 20 formed so as not to take material from the drum 10 are formed by modification or by local destruction of teeth of the comber 20. We detail these two methods below.

[0033] A first method consists of locally modifying the teeth of the comb 20, so as to make a part of the teeth inoperative or non-functional. Here, it is possible to seal or wrap teeth of the comb 20.

[0034] For example, the comber 20 may be equipped with pellets, for example made of cork, or lead, formed so as to close the space between the teeth of the comber 20 in predetermined zones, so as to define zones in which the teeth are no longer functional, and therefore in which the comber 20 cannot take material from the drum 10.

[0035] Alternatively, teeth of the comber 20 can be locally destroyed, so as to define areas in which the comber 20 cannot take material from the drum 10.

[0036] Thus, due to the areas in which the comber 20 cannot take material from the drum 10, the sheet formed at the outlet of the comber 20 has recesses. The device as proposed thus makes it possible to obtain directly at the outlet of the combers one or more sheets which can be described as perforated, without requiring a subsequent operation of cutting or removing material from the sheet.

[0037] The present invention thus makes it possible to directly obtain a sheet of openwork non-woven material, having recesses directly at the exit of the frame, without requiring cutting or material removal steps. figure 4 presents an example of a tablecloth thus obtained. It is understood that this example is not limiting, and is purely illustrative.

[0038] The invention thus contradicts the usual carding techniques which aim to form uniform and homogeneous textile sheets, and thus aim on the contrary to avoid the formation of areas devoid of material.

[0039] Furthermore, by thus producing the areas devoid of material from the formation of the sheet of material, and not during a subsequent step of cutting or removing material, the invention is compatible with the use of a thermo-bonding operation positioned directly downstream, or without the use of a thermo-bonding operation, thus making it possible to avoid a significant environmental impact.

[0040] Due to the presence of the zones of the comber 20 configured so as not to take material from the drum 10, it is understood that the comber 20 does not take all of the material present on the drum 10.

[0041] Thus, the present invention proposes adding a cleaning comb 40, adapted to recover the material present on the drum 10 downstream of the comb 20.

[0042] There figure 4 illustrates an example of such an embodiment. In this example, the device comprises 1 comber 20, as well as a cleaning comber 40 positioned between the material supply of the drum 10 and the comber 20. Thus, the material remaining on the drum 10 downstream of the combers 20 is recovered by the cleaning comber 40 before material is redeposited on the drum 10.

[0043] The cleaning comb 40 may typically comprise material recovery means, typically specific teeth or linings, and / or suction means adapted to recover the material present on the drum 10, typically all of the material present on the drum 10.

[0044] The material thus recovered by the cleaning comb 40 is typically reintroduced upstream of the material supply to the drum 10 using suitable reintroduction and conveying means. The cleaning comb 40 therefore performs a material recovery and recycling function.

[0045] The sheet formed at the card outlet can then be encapsulated by plastic or metallized films to form multi-layer reflective thermal insulators.

Claims

1. A device for forming a web of fibers of nonwoven material, comprising: - a rotating drum (10) having an outer face (12), suitable for being fed with textile fibers and for distributing same on the outer face (12) thereof, - at least one rotating doffer (20) comprising a plurality of teeth suitable for picking up textile fibers present on the outer face (12) of the drum (10) so as to form a web of material, said teeth being regularly distributed over an outer surface (22) of the doffer (20), characterized in that - said at least one doffer (20) being configured to form a web (30) with recesses, said at least one doffer (20) thereby comprising zones on the outer surface (22) thereof which cannot remove material from the drum (10), - the device further comprising a cleaning doffer (40), suitable for recovering the material present on the drum (10) downstream of said at least one doffer (20).

2. The device according to claim 1, comprising means for recovering the material removed by the cleaning doffer, and for reinserting said material to feed the drum (10).

3. The device according to one of claims 1 or 2, wherein the zones of the outer surface (22) of the at least one doffer (20) configured so as not to remove material from the drum (10) are formed by locally destroying teeth on the outer surface (22) of said at least one doffer (20).

4. The device according to one of claims 1 or 2, wherein the areas of the outer surface (22) of said at least one doffer (20) configured so as not to pick up material from the drum are formed by closing teeth on the outer surface (22) of said at least one doffer (20).

5. The device according to claim 4, wherein said tooth blocking on the outer surface (22) of said at least one doffer (20) is formed by affixing a pellet of material so as to block a volume between teeth of said at least one doffer (20).

6. A method of forming a web of fibers of nonwoven material using a carder, wherein - textile fibers are supplied, - the textile fibers are fed to a rotating drum (10), - textile fibers are removed from the rotating drum (10) with at least one rotating doffer (20) suitable for removing textile fibers from the drum (10), said rotating doffer (20) comprising a plurality of teeth suitable for removing textile fibers present on the outer face (22) of the drum (20) so as to form a web of material, said teeth being evenly distributed over an outer surface (22) of the doffer (20), characterized in that said doffer (20) is configured to present zones on the outer surface (22) thereof, which cannot remove material from the drum (10), so that the web (30) formed by the at least one doffer (20) is provided with recesses and in that - the material remaining on the rotating drum (10) downstream of said at least one rotating doffer (20) is recovered with a cleaning doffer (40).

7. The method according to claim 6, wherein following recovery of the material remaining on the rotating drum (10) downstream of said at least one rotating doffer (20) with a cleaning doffer (40), said material is reinjected upstream of the feed with material to the rotating drum (10).

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