Method and device for the transport of carded or air-laid nonwovens

Abstract

The system, in which a non-woven material (W) is transported by an air-permeable conveyor surface (1), has an aspiration chamber (4) with three separate compartments (41, 42, 43) beneath the conveyor so that air is drawn through the material and the permeable conveyor surface. The first compartment is located directly below the fibre dispersion chamber (2) of an airlay machine, while the second and third have air flow zones (Z2, Z3) with different flow rates, and an electrostatic charge zone between them. In the latter an ionising bar (5) applies an electrostatic charge to that material that causes it to adhere to the conveyor surface as it is carried along at a preferable speed of 150 metres per minute. The air flow rate is lower in the third zone (Z3) than in the second (Z2), but the difference is not great enough to alter the structure of the non-woven material.

Description

technical field [0001] [01] The present invention relates to improvements in the field of textiles for the transfer of nonwovens through an air-permeable transfer surface, in particular for the construction of nonwovens in the transition between two successive different aerodynamic zones A new technical approach to changing the problem, two successive aerodynamic zones are: an upstream zone and a downstream zone in which a first air flow across the nonwoven and conveying surface is generated and in the downstream zone a A second air flow that is weaker than the first air flow or no air flow at all is used across the nonwoven and the conveying surface. [0002] [02] The invention finds application preferably in the manufacture of nonwovens by hydrodynamic methods (voie aéraulique), ie by a technique commonly known in the field of carded nonwovens as "airlay". Background technique [0003] [03] non-woven fabric [0004] [04] Herein, any fiber and / or filament cloth or overla...

AI Technical Summary

Problems solved by technology

However, if the movement speed of the surface on which the nonwoven is formed and conveyed is increased, and thus the rotational speed of the transverse drums is correspondingly increased, a parasitic air flow is created which destroys the nonwoven when it passes under the pressure roller. Uniformity of nonwovens

[0019] [19] In addition, this small-diameter pressure roller rests against the nonwoven in an area of ​​small width, which can cause harmful deformations of the nonwoven

[0020] [20] Finally, this small diameter pressure roller creates the danger of fibers wrapping around the circumference of the roller

[0022] [22] However, this contact of the microporous sheet with the surface fibers of the nonwoven fabric at the outlet of the dispersion chamber produces friction, which deforms the nonwoven fabric and creates unevenness on the nonwoven fabric, and forms and conveys the The higher the speed at which the surface is moving, the greater this friction

However, in this case the same above-mentioned disadvantages were found with the pressure roller of document EP 0 093585

[0024] [24] In conclusion, the main disadvantage of all technical methods of the above-mentioned patents is that they all use a pressure mechanism at the outlet of the dispersion chamber that is in contact with the surface of the nonwoven

[0027] [27] However, when the non-woven fabric is passed from one suction area to another, this method of decreasing suction has the risk of changing or twisting the quality of the non-woven fabric.

[0029] [29] The above-mentioned disadvantages due to the use of pressure rollers in contact with the nonwoven are thus revisited, in particular the risk of permanent deformation of the nonwoven and the risk of fiber entanglement

[0040] [40] In particular, mass change is more of a problem for non-woven fabrics without reinforcement

[0041] [41] More particularly, this mass change is more of a problem for high conveying speeds, i.e. generally greater than 150 m / s for carded or "air layer" nonwovens that have not yet been consolidated

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