Textiles: fiber preparation – Working – Carding
Patent
1998-03-23
2000-06-13
Calvert, John J.
Textiles: fiber preparation
Working
Carding
19 98, 19106R, D01G 1502
Patent
active
060733136
DESCRIPTION:
BRIEF SUMMARY
The invention refers to an intermediate card for producing a nonwoven of fibrous material, with a main cylinder, with two web-forming rollers being in engagement with the main cylinder, with at least two card webs being taken off the main cylinder and being doubled by a take-off device.
The invention further refers to a method for producing a nonwoven of fibrous material by means of an intermediate card of the kind mentioned above by carding the fibrous material on a main cylinder, taking off at least two card webs from the main cylinder by means of at least two rollers independent of each other, and by joining the webs on a common roller to form a cross-linked card web.
From EP 0 330 750 A2, there is known an intermediate card for a random laid nonwoven with at least three worker rollers rotating in the same sense as the main cylinder, in which the first working cylinder is in engagement with the main cylinder while the two further working rollers each are in engagement with the first working roller. The two rollers downstream thereof in engagement with the first working roller cause a division of the card web being formed by the first working roller, the card webs being redoubled on transport belts downstream thereof.
Furthermore, there are known carding assemblies of the Hergeth Hollingsworth company (card model H 6.345) in which two random rollers are in engagement with a main cylinder, each producing a random laid web finally laid down on one transport belt each. The doubling of the two random laid webs occurs by joining the two webs on the transport belt.
The nonwoven thus produced consists of two web layers disadvantageously lying on top of each other only in a loose manner and not being cross-linked. An interconnection of the layers only occurs in one or more processing steps subsequent to the carding.
The invention is based on the objective to produce an intermediate card of the latter kind as well as a method for producing a nonwoven wherein the nonwoven produced is already cross-linked in the carding step and wherein the production process, especially in the case of light webs and high production speeds, can be controlled in a better way and wherein the constructive requirements for the production machine are reduced.
This objective is achieved by the characteristics of claims 1 and 17, respectively.
The invention provides, in an advantageous manner, that at least one of the web-forming rollers arranged between the main cylinder and the take-off device is a random roller with an associated centrifugal trough and with fittings for producing a random orientation of the card web.
Such an intermediate card allows to join and simultaneously cross-link multiple webs in the carding step downstream of the web-forming rollers and upstream of the take-off device. Another advantage is the fact that overlaying web fabrics can be produced which are a combination of at least one random laid web and a longitudinally directed nonwoven. Thus, a closely cross-linked card web can be produced. The randomly laid nonwoven is formed in combination with a centrifugal trough and fittings with a small front rake. The randomly laid nonwoven is formed by means of a centrifugal trough in a centrifugal dynamic manner, the web initially being subjected to a stuffing effect and then being freed from the dynamic or stuffing pressure. Thus, the formation of the randomly laid nonwoven occurs after the fibers have been freed from the dynamic effect of the random roller on a subsequent roller. The orientation of the fibers in the nonwoven is three-dimensional, i. e. random or isotropic.
Downstream of the doffer roller, only a single take-off device and a single transport belt are required. In this manner, the constructive requirements for producing doubled card webs are reduced, while the production process, especially in the case of. light webs and a high production speed, can be controlled in a better way.
The circumferential speed of the main cylinder is more than 500 m/min, preferably more than 1000 m/min.
The circumferential s
REFERENCES:
patent: 656403 (1900-08-01), Gessner
patent: 2987779 (1961-06-01), Kawashima
patent: 4299011 (1981-11-01), Rothen et al.
patent: 5226214 (1993-07-01), Napolitano
Andermann Jurgen
Lasenga Werner
Calvert John J.
Spinnbau GmbH
Welch Gary L.
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