Method for molding fibrous material

Abstract

A device for producing a three dimensional shaped consolidated product. The device includes a rotary drum, defined as a rotary conveyor with a peripheral surface extending in circumferential direction with at least one product shaping area in the form of a cavity on said peripheral surface, the peripheral surface is pervious to air at least in the product shaping area, at least one material feed device to feed a base material into the at least one cavity, a vacuum device designed to generate a negative pressure at least in the at least one cavity, whereby the generated suction is directed towards the interior of the rotary conveyor, and whereby downstream of the material feed device at least one consolidating device is located such that at least a part of the filled cavity is subjected to a consolidating treatment whereby the base material at least partly will adhere to neighboring material.

Claims

1. A method for producing a three-dimensional consolidated fibrous product, comprising: providing a device having a rotary drum with a product-shaping area in the form of a cavity provided on a peripheral surface thereof; providing a first processing zone comprised of a feeding apparatus adapted to feed loose fiber base material into the cavity; rotating the rotary drum to place the product shaping area adjacent to the loose fiber base material feeding apparatus; feeding loose base material into the product-shaping areas as the product shaping area rotates through the feeding zone, which results is filling the at least a portion of the cavity defined by the product-shaping area with loose fiber base material; providing a second processing zone comprised of a heating device that is adapted to consolidate the loose fiber base material by heat setting; consolidating at least a portion of the loose fiber base material by heating the cavity, whereby the fibers in the loose fibrous base material in the cavity are at least partially adhered as the product-shaping area rotates through the second processing zone providing a third processing zone that is adapted to cool the material in the cavity; cooling the at least partially-consolidated base material to form a consolidated base material in the cavity as the product-shaping area rotates through the third processing zone, to form the three-dimensional consolidated fibrous product; providing a fourth processing zone adapted to remove the three-dimensional consolidated fibrous product from the cavity; demolding the three-dimensional consolidated fibrous product as the product-shaping area rotates through fourth processing zone; and rotating the product-shaping area into the feeding zone to complete the rotational cycle.

2. The method of claim 1, wherein the loose fiber base material comprises at least one of natural fibers, synthetic fibers, binding materials that are activated during the consolidating.

3. The method of claim 1, wherein the third processing zone employs active cooling between the second processing zone and the fourth processing zone, the cooling device configured to direct airflow towards the cavity, the airflow having a temperature less than that of ambient air.

4. The method of claim 1, wherein the second processing zone delivers thermal energy to the loose fibrous base material by at least one of heat radiation and convective heat transfer, and wherein the heating device does not provide contact heating.

5. The method of claim 1, wherein the second processing zone is comprised of a first heating zone and a second heating zone, and wherein the at least one heating device is configured to provide a heat of a first temperature to the first heating zone and heat of a second temperature to the second heating zone.

6. The method of claim 1, wherein the cavity spans a width of the rotary drum.

7. The method of claim 1, wherein the feeding apparatus comprises one or more transport rollers.

8. The method of claim 1, wherein the feeding apparatus is a carding roller.

9. The method of claim 1, wherein the rotary drum employs a vacuum device designed to generate a negative pressure at least in the at least one cavity, thereby generating suction directed towards an interior of the rotary conveyor.

10. The method of claim 9, wherein the negative pressure is comprised of a first negative pressure and a second negative pressure, the first negative pressure and the second negative pressure being different.

11. The method of claim 1, wherein the cavity is lined with an air pervious material selected from a group consisting of metal mesh and wire cloth.

12. The method of claim 11, wherein the air pervious material has a first portion that provides a first air resistance and a second portion that provides a second air resistance.

13. A three-dimensional consolidated fibrous product manufactured by the method of claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows a schematic drawing of the device according to the invention.

(2) FIG. 2 shows a schematic drawing of the device according to the invention from a different angle.

(3) FIG. 3 shows an example of a consolidated product preform or end product.

(4) FIG. 1 shows the device according to the invention. The core of the device forms a rotary drum 3 with at least one cavity 4. The surface is at least partially pervious at the areas of the cavity forming the shape of the wanted product. In the cavity at the side facing the fiber stream the fibers are collected until the cavity is full. Preferably a device for elimination of excess material is given, before the consolidation zone. A take-off roller or a scraping knife, or alternative solutions known in the art can be used for this purpose. Another solution is a combination with the feeding device.

(5) Inside the drum a device or means for producing a negative pressure in the cavity where the product is formed is located. This can be for instance a vacuum device or connections to an external vacuum device. The connections to the vacuum device can be built independently for the different processing zones. Airstreams through the cavity are shown with arrows.

(6) Due to the rotary movement the cavities will pass different processing steps or zones. These different processing steps or zones are as follows: A. Feeding of the base material into the cavity; B. Consolidation of the base material collected in the cavity; C. Eventually cooling of the consolidated material in the cavity; D. Demolding of the three-dimensional shaped consolidated material from the cavity.

(7) The device 2 in zone A is an example of such base material feeding device that can be used according to the invention. The fibrous stream is fed in the cavity using a carding roll which at the same time also removes surplus material as disclosed in WO 2007/134812.

(8) The filled cavities 4 are passing in zone B at least one consolidating device for instance a heating device for thermal treatment of the cavity filled with base material to heat-set the material. In the example two thermal zones are used, b1 and b2, whereby the temperature Tb1 is different from Tb2. As the transfer of heat is dependent on the material properties as well as the temperature of the material, it might be necessary to keep a certain delta between the temperature of the fluid used and the temperature of the product. In particularly care has to be taken that the material is not damagedoverheated and burnton the surface, as this can have a negative effect on the product quality. The use of different temperature zones has the advantage that the amount of heat transferred can be adjusted more optimally. An example of a temperature zoning can be a heat up zone and a zone where the temperature is kept constant at a higher level. The consolidation of the base material is dependent on the overall heat that is put into the material. Preferably a hot air flow, the temperature of the hot air and eventually the pressure in the treatment zone can be adjusted.

(9) Downstream of the consolidating process zone the consolidated product can be demolded in a subsequent processing zone D. The three-dimensional shaped, consolidated product 8 is removed from the product-forming cavity. In the simplest form the product can be transferred to a table, or other form of stationary device that is used for collecting the consolidated products, or it is in the form of a conveying device for transport of the consolidated product for further processing, for instance a conveyer belt 7 or robotic transport or it is a combination depending on the actual product produced.

(10) FIG. 2 shows the rotary drum 3 with 2 cavities 4, which rotates around an axis of rotation 9 and has a certain width w and a certain radius r. With a dashed line the consolidation zone B is given that extends at least over the largest width of the cavity, but preferably over the complete width of the drum W. The dwell time is dependent on the rotary speed of the drum, as also the feeding of the cavity, the cooling and the lay down is dependent on this factor, therefore the dwell time can only be regulated with the length L of the circumferential area that is opposite the consolidating device as shown in the dashed line.

(11) For instance the cooling area 6 in the cooling zone C in FIG. 1 might be adjustable to extend the consolidating area.

(12) FIG. 3 shows an example of a three-dimensional shaped consolidated product 8 made of base material for instance fibers produced according to the invention, with technical design features, that includes a re-entrant portion 12, a hole 10 and an area with a thickness reduction 11.