Abstract
The present disclosure relates to a method (100) for producing 3D fiber structures, the method (100) comprising the steps of: feeding (101) a foamed fiber furnish (2) to an apparatus (1), the apparatus (1) comprising a liquid-permeable substrate means (3) having a first side (4) and an opposing second side (5), a dispenser (6) having an outlet (7), wherein at least one of the dispenser (6) and the substrate means (3) travel with respect to the other. Further comprising the step of dispensing (102), by means of the dispenser (6), a layer (2) of foamed fiber furnish to the first side of said liquid-permeable substrate means (3), wherein the apparatus (1) further comprises at least a reservoir (8) and a first vacuum unit (9) associated with the second side (5) of the liquid-permeable substrate means (3) so to collect fluid discharge from the dispensed layer (2) of foamed fiber furnish. Further comprising the step of applying (103) at least a first dewatering pressure to at least a part of the second side (5) of said substrate means (3).
Claims
1. A method for producing 3D fiber structures, the method comprising: feeding a foamed fiber furnish to an apparatus, the apparatus comprising: a liquid-permeable substrate means having a first side and an opposing second side; a dispenser having an outlet, wherein at least one of the dispenser and the substrate means travel with respect to the other; dispensing, by means of the dispenser, a layer of foamed fiber furnish to the first side of said liquid-permeable substrate means, so to obtain a fibrous mat, wherein the apparatus further comprises at least a reservoir and a first vacuum unit associated with the second side of the liquid-permeable substrate means so to collect fluid discharge from the dispensed layer of fibrous mat; applying at least a first dewatering pressure to at least a part of the second side of said substrate means.
2. The method according to claim 1, wherein the layer of fibrous mat is dispensed so to comprise a predefined substantially uniform thickness, wherein the apparatus is configured to, preceding the step of applying a first dewatering pressure: by means of the reservoir, collect fluid discharge for a first period of time based on at least the thickness of the layer.
3. The method according to claim 1, wherein the first dewatering pressure is applied for a second period of time, wherein the first dewatering pressure is within a range of 70 kPa-100 kPa.
4. The method according to claim 2, wherein the first period of time is 1-10 minutes, wherein the second period of time is 2-10 minutes, wherein the thickness of the layer is within a range of 1-10 cm.
5. The method according to claim 1, wherein the liquid-permeable substrate means travels in a first direction along a length defined by at least a first and a second portion, wherein the dispenser is arranged to be above the first side of the substrate means (3) in said first portion, wherein the reservoir is arranged in said first portion, wherein the first vacuum unit and a second vacuum unit are arranged sequentially along the length in said second portion, wherein the first vacuum unit is closer to the reservoir than the second vacuum unit.
6. The method according to claim 5, wherein the first vacuum unit is configured to: apply a first dewatering pressure, wherein the second vacuum unit is configured to apply a second dewatering pressure, wherein the first dewatering pressure is greater than the second dewatering pressure.
7. The method according to claim 6, wherein the second dewatering pressure is within a range of 50 kPa-80 kPa.
8. The method according to any of the claim 1, wherein the method further comprises the step of, preceding the step of applying a first dewatering pressure: applying an ultrasonic radiation towards the substrate means.
9. The method according to claim 5, wherein the method is performed in a continuous process.
10. The method according to claim 1, wherein the foamed fiber furnish comprises a fiber consistency in a range of 0.5-10% based on a dry weight of the fibers, wherein the foamed fiber furnish comprises a total concentration of foaming agents in a range of 0.05-2 g/l, wherein the foamed fiber furnish comprises an air content in a range of 55-70% by volume, wherein the foamed fiber furnish is generated from a pulp slurry.
11. An apparatus for producing 3D fiber structures, the apparatus comprising: a liquid-permeable substrate means having a first side and an opposing second side; a dispenser having an outlet, wherein at least one of the dispenser and the substrate means travel with respect to the other; a reservoir; at least a first vacuum unit; wherein the apparatus is configured to perform the method in accordance with claim 1.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In the following the invention will be described in a non-limiting way and in more detail with reference to exemplary embodiments illustrated in the enclosed drawings, in which:
[0025] FIG. 1 illustrates from a side-view an apparatus in accordance with an embodiment of the present disclosure;
[0026] FIG. 2 illustrates from a side-view an apparatus in accordance with an embodiment of the present disclosure, the apparatus having a reservoir and a first and a second vacuum unit;
[0027] FIG. 3 illustrates an apparatus in accordance with an embodiment of the present disclosure, the apparatus having a reservoir, a first and a second vacuum unit and an airborne ultrasonic unit;
[0028] FIG. 4 illustrates the apparatus of FIG. 1 having a layer of foamed fiber furnish on the substrate means;
[0029] FIG. 5 illustrates a method for producing 3D fiber structure in accordance with an embodiment of the present disclosure;
[0030] FIG. 6 illustrates a method for producing 3D fiber structure in accordance with an embodiment of the present disclosure;
[0031] FIG. 7A illustrates a representation of a single fiber orientation in a 2D fibrous structure;
[0032] FIG. 7B illustrates a representation of a single fiber orientation in a 3D fibrous structure.
DETAILED DESCRIPTION
[0033] In the following detailed description, some embodiments of the present disclosure will be described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways, unless anything else is specifically indicated. Even though in the following description, numerous specific details are set forth to provide a more thorough understanding of the provided method and apparatus, it will be apparent to one skilled in the art that the method and apparatus may be realized without these details. In other instances, well known constructions or functions are not described in detail, so as not to obscure the present disclosure.
[0034] FIG. 1 illustrates an apparatus 1 for producing 3D fiber structures. The apparatus 1 comprises a liquid-permeable substrate means 3 having a first side 4 and an opposing second side 5, a dispenser 6 having an outlet 7, wherein at least one of the dispenser 6 and the substrate means 3 travel with respect to the other. In some embodiments the dispenser 6 is arranged to have a fixed position so that the substrate means 3 travels relative the dispenser 6 in a first direction x1.
[0035] The apparatus 1 shown in FIG. 1 further comprises at least a reservoir 8 and a first vacuum unit 9 associated with the second side 5 of the liquid-permeable substrate means 3 so to collect fluid discharge from the dispensed layer 2 of foamed fiber furnish. As seen in FIG. 1 the reservoir 8 and the first vacuum unit 9 may be integrated.
[0036] FIG. 2 shows the apparatus 1 according to some embodiments wherein the apparatus 1 also comprises a second vacuum unit 9.
[0037] FIG. 3 shows the apparatus 1 according to some embodiments wherein the apparatus 1 also comprises an ultrasonic unit 12.
[0038] FIG. 4 shows the apparatus 1 in FIG. 1 wherein there is a layer 2 of foamed fiber furnish applied on the substrate means 3 traveling in a first direction x1.
[0039] FIG. 5 schematically illustrates a method 100 for producing 3D fiber structures, the method 100 comprising the steps of: feeding 101 a foamed fiber furnish 2 to an apparatus 1 e.g. any of the apparatus 1 shown in FIGS. 1-3, the apparatus 1 comprising a liquid-permeable substrate means 3 having a first side 4 and an opposing second side 5, a dispenser 6 having an outlet 7, wherein at least one of the dispenser 6 and the substrate means 3 travel with respect to the other. Further comprising the step of dispensing 102, by means of the dispenser 6, a layer 2 of foamed fiber furnish to the first side of said liquid-permeable substrate means 3, wherein the apparatus 1 further comprises at least a reservoir 8 and a first vacuum unit 9 associated with the second side 5 of the liquid-permeable substrate means 3 so to collect fluid discharge from the dispensed layer 2 of foamed fiber furnish. Further comprising the step of applying 103 at least a first dewatering pressure to at least a part of the second side 5 of said substrate means 3. The first dewatering pressure may be applied for a second period of time, wherein the first dewatering pressure is within the range of 70 kPa-100 kPa.
[0040] The layer 2 of foamed fiber furnish may be dispensed so to comprise a predefined substantially uniform thickness, wherein the apparatus 1 may be configured to (as seen in FIG. 5), preceding the step of applying a first dewatering pressure 103, by means of the reservoir 8, collect 104 fluid discharge for a first period of time based on at least the thickness of the layer 2. The first period of time may be 1-10 minutes, wherein the second period of time may be 2-10 minutes, wherein the thickness of the layer 2 is within the range of 1-10 cm.
[0041] As shown in the apparatus in FIGS. 2 and 3, the liquid-permeable substrate means 3 may travel in a first direction x1 along a traveling element 13 having a length L1 defined by at least a first and a second portion 15, 15, wherein the dispenser is arranged to be above the first side of the substrate means 3 in said first portion 15, wherein the reservoir 8 is arranged in said first portion 15, wherein the first vacuum unit and a second vacuum unit 9, 9 are arranged sequentially along the length L1 in said second portion 9, wherein the first vacuum unit 9 is closer to the reservoir 8 than the second vacuum unit 9. The traveling element 13 may be any suitable traveling element 13 that allows the substrate means 3 to travel along a length L1. Accordingly, the length L1 may also be defined as the working length (i.e. the distance between two points where the apparatus performs the steps in the method 100) of the substrate means 3, thus it doesn't necessarily define the total length of the substrate means 3 as it may in e.g. a continuous embodiment extend even longer than the length L1. It should be noted that the term dewatering pressure may be interchanged with the tem suction.
[0042] Further referring to the apparatus in FIG. 2 performing the method 100. The first vacuum unit 9 may be configured to apply a first dewatering pressure, wherein the second vacuum unit 9 is configured to apply a second dewatering pressure, wherein the first dewatering pressure is greater than the second dewatering pressure. The mentioned procedure allows the layer of foamed fiber furnish 2 to be treated in a continuous manner while traveling in the first direction x1. Thus, the method 100 may be performed in a continuous process. The continuous process may be performed in a manner that allows the reservoir 8 to collect liquid from the applied foamed fiber furnish 2 while traveling towards the first vacuum unit 9 where a first dewatering pressure is applied, followed by that the foamed fiber furnish continues to travel towards the second vacuum unit 9 where a second dewatering pressure is applied. The substrate means 3 may in other words travel according to a closed loop i.e., similar to how a conveyor belt operates.
[0043] FIG. 6 shows the method 100 performed by the apparatus shown in FIG. 3, wherein the method 100 further comprises the step of, preceding the step of applying at least one of the first and the second dewatering pressure 103, applying 105 an ultrasonic radiation to the first side of said substrate means. The ultrasonic radiation may in some embodiments be applied simultaneously as the first and/or the second vacuum unit 9, 9 are operating. Thus, the method 100 in FIG. 6 comprises the steps of feeding 101 a foamed fiber furnish 2 to an apparatus 1, the apparatus 1, dispensing 102, a layer 2 of foamed fiber furnish to the first side 4 of said liquid-permeable substrate means 3, applying 105 an ultrasonic radiation to the substrate means 3, applying 103 at least a first dewatering pressure. The reservoir 8 may simultaneously intermediate/during the steps 102-105 collect 104 fluid discharge for a first period of time based on at least the thickness of the layer 2.
[0044] The configuration of fibers in the bulk of the structure can be described by fiber orientation distribution of all fibers using a pair of angles (,), shown in exemplary FIGS. 7A-7B, where 7A illustrates a representation of a single fiber orientation in a 2D structure and 7B illustrates a single fiber orientation in a 3D fibrous structure (which is obtained by the method of the present disclosure). For every fiber denoted i, .sub.i is the angle between Z-axis and the fiber, and .sub.i is the angle between X-axis and the projection of the fiber on the XY-plane (disclosed in FIG. 7A-7B). The angle may have any random value in both 2D and 3D structures, however, in 2D structure 90.
