PROCESS AND APPARATUS FOR PRODUCING A MOLDED FIBER ARTICLE

Abstract

The invention relates to a process and an apparatus for producing a molded fiber article. The process comprises the steps of dissolving fibrous materials in water to form a fibrous material suspension in a pulper, removing moisture from the fibrous material suspension by pressing to form a molded fiber article in a mold and/or drying the molded fiber article by supplying heat, demolding the molded fiber article from the mold. The process is characterized by the feature whereby, in mold drying of the molded fiber article in the mold, a moisture content of the molded fiber article of not more than 10% by weight or not more than 7.5% by weight or not more than 5% by weight is achieved.

Claims

1. Process for producing a molded fiber article comprising the steps Dissolving of fibrous materials in water to form a fibrous material suspension in a pulper, Dehumidifying of the fibrous material suspension by pressing to form a molded fiber article in a mold and/or Drying the molded fiber article by supplying heat to the mold and Demolding of the molded fiber article from the mold, in which during a mold drying of the molded fiber article, the molded fiber article is subjected to electromagnetic waves in such a way that it dries in the mold until a moisture content of the molded fiber article of not more than 10% by weight or not more than 7.5% by weight or not more than 5% by weight is achieved, wherein the molded fiber article is dried in a drying station and demolded from the mold in a demolding station, wherein the pulper, the drying station and the demolding station form workstations.

2. Process according to claim 1, wherein the molded fiber article after dehumidifying the fibrous material suspension in the mold has a moisture content of not more than 30% by weight or not more than 25% by weight or not more than 20% by weight.

3. (canceled)

4. Process according to claim 1, wherein, the mold is conveyed by means of a transport device, from the pulper to the drying station and to the demolding station.

5. Process according to claim 1, wherein one or more molds are releasably attached to at least one of the workstations and/or to the transport device (6), so that, after processing in at least one of the workstations, one or more molds are coupled into or out of one of the workstations and/or the transport device accordingly, preferably automatically.

6. Process according to claim 1, wherein one or more molds are conveyed in at least one circuit by means of the transport device.

7. Process according to claim 1, wherein a step of dripping the molded fiber article in the mold is provided between step of dehumidifying and drying.

8. Process according to claim 1, wherein the drying station and/or a cooling station and/or the demolding station are arranged in a transport direction along the transport device and can receive at least one mold for processing in succession or simultaneously.

9. Process according to claim 1. wherein the drying station and/or a cooling station and/or the demolding station are arranged in the transport direction along the transport device, it also being possible for in each case a plurality of workstations, in particular drying stations being provided to be able to receive two or more molds for processing in succession and/or simultaneously.

10. Process according to claim 1, wherein the mold is placed between at least two capacitor plates of the drying station, wherein the electromagnetic waves being applied to the mold via the capacitor plates.

11. Process according to claim 1, wherein electromagnetic waves are generated in the drying station by a wave generator and are introduced via a waveguide into a capacitor plate with a mold receiving area.

12. Process according to claim 1, wherein electromagnetic waves are generated in the drying station by a wave generator and are introduced via a waveguide into a capacitor plate with a mold receiving area, and wherein the capacitor plate has a first dielectric layer in the mold receiving area, and a mold made of an electrically conductive material is arranged in the mold so that the capacitor plate forms a first capacitor with one first mold half of the mold, and wherein a second dielectric layer is provided in a contact region between the first mold half and a second mold half, so that the first mold half and the second mold half form a second capacitor.

13. Process according to claim 1, characterized in that, wherein electromagnetic waves are generated in the drying station by a wave generator and are introduced via a waveguide into a capacitor plate with a mold receiving area, and wherein between the capacitor plate and a ground plate, the mold is directly received, wherein the mold is formed of a dielectric material, so that the capacitor plate and the ground plate form a capacitor.

14. Process according to claim 1, wherein simultaneously with the application of the electromagnetic waves, the molded fiber article in the mold is compressed in the drying station.

15. Apparatus for producing a molded fiber article, comprising a pulper for dissolving fibrous materials in water to form a fibrous material suspension, a mold comprising two mold halves for dehumidifying the fibrous material suspension by pressing to form a molded fiber article, a drying station for drying the molded fiber article while supplying heat in the mold, and a demolding station for demolding the molded fiber article from the mold, in which, the drying station comprises a wave generator for electromagnetic waves and a control device, which are designed in such a way that the molded fiber article is dried by means of the electromagnetic waves to a moisture content of not more than 10% by weight or not more than 7.5% by weight or not more than 5% by weight, wherein a transport device is provided, by means of which the mold can be conveyed from the pulper to the drying station and to the demolding station.

16. Apparatus according to claim 1, wherein the mold comprises a temperature sensor and/or a humidity sensor, the control device for controlling the wave generator being designed in such a way that energy is supplied to the mold by means of the electromagnetic waves in accordance with the measured temperature and/or the measured humidity.

17. (canceled)

18. Apparatus according to claim 1, characterized in that, one or more molds are provided, which can releasably attached again to the workstations and/or the transport device (and can be opened and closed there automatically).

19. Apparatus according to claim 1, wherein the mold halves and/or the transport device and/or the workstations have connecting means for coupling and uncoupling the mold halves.

20. Apparatus according to claim 14, wherein coupling/uncoupling means are provided for coupling the molds to and from the transport device and/or the workstations.

21. Apparatus according to claim 14, wherein between the pulper and the drying station (4), a dripping device for dripping one or more molded fiber articles, is provided, which is formed either by an area of the transport device or by a separate buffer area decoupled from the transport device.

22. Apparatus according to claim 14, wherein the drying station comprises two capacitor plates, between which the mold can be arranged in a mold receiving area, and wherein the electromagnetic waves can be applied to the mold by means of the capacitor plates.

23. Apparatus according to claim 14, wherein the drying station comprises a wave generator for generating electromagnetic waves, a waveguide and a capacitor plate comprising a mold receiving area, the electromagnetic waves can be introduced from the wave generator into the capacitor plate via the waveguide.

24. Apparatus according to claim 21, wherein the capacitor plate has a first dielectric layer in the mold receiving area, and a mold comprised of an electrically conductive material can be arranged in the mold receiving area, so that the capacitor plate forms a first capacitor with a first mold half of the mold, wherein a second dielectric layer is provided in a contact region between the first mold half and a second mold half, so that the first mold half and the second mold half form a second capacitor.

25. Apparatus according to claim 21, wherein between the capacitor plate and a ground plate, the mold is directly received, wherein the mold is formed of a dielectric material, so that the capacitor plate and the ground plate form a capacitor.

26. Apparatus according to claim 14, wherein the apparatus is designed to carry out a process for producing a molded fiber article comprising the steps Dissolving of fibrous materials in water to form a fibrous material suspension in a pulper Dehumidifying of the fibrous material suspension by pressing to form a molded fiber article in a mold and/or Drying the molded fiber article by supplying heat to the mold and Demolding of the molded fiber article from the mold, in which during a mold drying of the molded fiber article, the molded fiber article is subjected to electromagnetic waves in such a way that it dries in the mold until a moisture content of the molded fiber article of not more than 10% by weight or not more than 7.5% by weight or not more than 5% by weight is achieved, wherein the molded fiber article is dried in a drying station and demolded from the mold in a demolding station, wherein the pulper, the drying station and the demolding station forming workstations.

Description

[0126] Further tasks, features and advantages of the present invention are apparent from the description of the exemplary embodiment, which is illustrated in the accompanying drawing. This shows in:

[0127] FIG. 1 a schematic representation of an apparatus according to the invention.

[0128] In the following, an apparatus 1 according to the invention for producing a molded fiber article 2 is described in more detail based on an embodiment example (FIG. 1).

[0129] The apparatus 1 comprises a pulper 3, a drying station 4, a demolding station 5 and a transport device 6.

[0130] The transport device 6 comprises an upper and a lower conveyor belt device 7, 8 and a first and a second lifting device 9, 10 and is designed to transport a mold 11 in the apparatus 1 in a circuit. In this way, the transport device 6 enables one or more molds 11 to be transported in a circuit along a transport direction 12.

[0131] The linear conveyor belt devices 7, 8 are coupled to the lifting devices 9, 10 at their respective ends in such a way that the mold 11 is transported from one of the conveyor belt devices 7, 8 to the corresponding lifting devices 9, 10 and vice versa.

[0132] The conveyor belt devices 7, 8 can comprise one or more transport sections each with a conveyor belt, which are each guided around two deflection rollers and are driven independently of each other. The individual transport sections can comprise different lengths and move at different speeds. Thus, the dwell time of the individual molds 11 on the respective transport sections can be adjusted. For example, a transport section can serve as a buffer by being slowly driven and transporting many molds 11, which are arranged at a small distance on the transport section.

[0133] With the upper conveyor belt device 7, the mold 11 is moved from a starting position 13, which designates a position on the upper conveyor belt device 7 downstream of the first lifting device 9 and upstream of the pulper 3, to the individual workstations.

[0134] The lower conveyor belt device 8 runs in the opposite direction to the upper conveyor belt device 7 to transport the mold 11 from a second lifting device 10 in reverse direction 14 to the first lifting device 9.

[0135] The lifting devices 9, 10 each comprise a single movable platform 15, 16, which is moved up and down. However, the lifting devices 9, 10 can also be designed as paternoster lifts, each with several rotating platforms.

[0136] The movable platforms 15, 16 are designed as passive roller conveyors, so that the molds 11 can be easily picked up and discharged again.

[0137] The first lifting device 9 is coupled to the lower conveyor belt device 8 and to the upper conveyor belt device 7 and is arranged at one end of each of them to

[0138] lift the mold 11 for starting the production process of a molded fiber article 2 from the lower conveyor belt device 8 to the upper conveyor belt device 7.

[0139] The second lifting device 10 is coupled to the upper conveyor belt device 7 and to the lower conveyor belt device 8 and is arranged at one end of each of them to lower the mold 11 after completion of the production process of a molded fiber article 2 from the upper conveyor belt device 7 to the lower conveyor belt device 8.

[0140] A slide 17, 18 is arranged on each of the conveyor belt device 7, 8 at their front end in the conveying direction or in the transport direction 12 and is designed as a passive roller conveyor so that the molds 11 can slide automatically from the conveyor belt devices 7, 8 onto the corresponding movable platforms 15, 16 of the lifting devices 9, 10.

[0141] A first slide 19 is arranged on the first lifting device 9 at the level of the upper conveyor belt device 7 to push the mold 11 from the platform 15 of the first lifting device 9 onto the upper conveyor belt device 7 and to the starting position 13 in front of the pulper 3.

[0142] A second slide 20 is arranged on the second lifting device 10 at the level of the lower conveyor belt device 8 to push the mold 11 from the platform 16 of the second lifting device 10 onto the lower conveyor belt device 8.

[0143] The mold 11 is formed of a lower mold half 21 and an upper mold half 22. In addition, the mold 11 is made of a of a material that is transparent to electromagnetic waves so that electromagnetic waves can be transmitted to the molded fiber article 2 with a low loss. The material is, for example, high molecular weight polyethylene (PE), polyetheretherketone (PEEK) or another non-polar plastic. The wall thickness of the mold halves 21, 22 is as thin as possible, so that the electromagnetic waves are only absorbed to a small extent.

[0144] The mold halves 21, 22 each comprise an outer and inner surface, the inner surfaces delimiting a mold interior space when the mold 11 is closed, the mold interior space being complementary to the respective shape of the molded fiber article 2 to be produced.

[0145] The lower mold half 21 is formed of a grid with a plurality of through holes or a porous material, so that water can escape downward.

[0146] The mold halves 21, 22 are held together in the closed state by means of frictional or positive locking. The mold halves 21, 22 can additionally and/or alternatively be frictionally and/or positively connected to one another by a locking means such as, for example, a locking mechanism or a latching device.

[0147] In the present embodiment, no locking means is provided because the mold halves 21, 22 are held together by adhesion after molding.

[0148] The mold halves 21, 22 have fitting elements at contacting interfaces. These fitting elements are wedges or conical elements and corresponding recesses, with one of the two mold halves 21, 22 providing the wedges and the other mold half 22, 21 providing the appropriate recesses. When the upper mold half 22 is placed with a small offset on the lower mold half 21, the wedges ensure that the mold halves 21, 22 assume the desired position relative to one another. In this case, the wedges of the one mold half 21, 22 slide into the recesses provided for this purpose in the other mold half 22, 21.

[0149] Pins and corresponding drill holes are provided as further fitting elements, one of the mold halves 21, 22 providing the pins and the other mold half 22, 21 providing the matching drill holes. When the mold halves 21, 22 are placed on top of each other, the pins engage in the drill holes provided for this purpose and consequently prevent horizontal displacement of the mold halves 21, 22 relative to one another.

[0150] The pins are designed so long that they only meet the corresponding drill holes after the wedges have slid into the recesses provided for this purpose and have ensured the correct alignment of the mold halves 21, 22 with respect to one another. The mold halves 21, 22 have at least one integrated hollow rail on the outside for a slide closure, the hollow rail of the lower mold half 21 being formed parallel to the hollow rail of the upper mold half 22. The hollow rails are designed to be as flat as possible to match the wall thickness of the mold halves 21, 22. The hollow rails are designed to be open on one side and are provided for horizontal displacement of the mold halves 21, 22 into a corresponding counter profile. The hollow rails can be designed, for example, as T-grooves or as dovetail grooves.

[0151] The pulper 3, the drying station 4 and the demolding station 5 each comprise an apparatus which comprises at least one corresponding projecting profile rail as a counterpart to the hollow rails of the mold halves 21, 22. The profile rails are open on one side, preferably with a latching means. The open side of the profile rails points in the direction of the upper conveyor belt device 7, so that the mold halves 21, 22 of the upper conveyor belt device 7 can be pushed onto the profile rails in such a way that the hollow rails of the mold halves 21, 22 engage in the profile rails. In this way, the mold halves 21, 22 can be coupled to the respective workstation. The counter profile can be designed, for example, as a T-profile or as a fitting connector.

[0152] The mold halves 21, 22 have beveled corners that can serve as guide surfaces when pushing the mold halves 21, 22. The workstations each comprise an apparatus, which comprises corresponding counter-guide surfaces for the guide surfaces of the mold halves 21, 22. The counter-guide surfaces run from the upper conveyor belt device 7 in a conically tapering manner in the direction of the workstation. They are designed in such a way that they engage with the guide surfaces of the mold halves 21, 22 as soon as the mold halves 21, 22 leave the upper conveyor belt device 7 during pushing in the direction of the workstation. The counter-guide surfaces run towards the corresponding working position at the workstations, whereby they ensure an exact positioning of the mold halves 21, 22 at the working positions.

[0153] A first transport section of the upper conveyor belt device 7 extends in the transport direction 12 from the first lifting device 9 to a height in front of the pulper 3. Subsequently, and at a minimum distance from the first transport section, a second transport section follows, whereby an automatic transfer of a mold 11 can take place. The second transport section runs parallel to the pulper 3 in such a way that it can provide the pulper 3 with a mold 11 and pick it up again from there. The second transport section comprises a conveyor belt, which is grid-shaped with a plurality of openings so that water can drip into a basin located below.

[0154] The pulper 3 comprises an upwardly open container 25 and is arranged adjacent to the transport device 6 in such a way that the upper edge of the container 25 is arranged approximately at the level of the upper conveyor belt device 7.

[0155] A shredder device (not shown) can be provided, which is designed to break up or shred a fibrous material so that the fibrous material is present in thin fiber strands. In the case of a starting material that is already present in thin fiber strands, the shredder device can also be omitted, and the fibrous material can be fed directly to the pulper 3.

[0156] The pulper 3 has an agitator (not shown) with a stirrer driven by a motor to mix the fibrous material with water to form a fibrous material suspension. This fibrous material suspension is a viscous pulp that can be conveyed from the pulper 3 into the container 23 by means of a pump (not shown).

[0157] The pulper 3 comprises a lower lifting device 24 and an upper lifting device 25, which can be moved vertically. The lower lifting device 24 is integrated in the container 23 of the pulper 3. In the present embodiment, the lifting devices 24, 25 are each a piston/cylinder unit.

[0158] The lifting devices 24, 25 comprise at least one protruding profile rail, preferably with a latching means to receive the corresponding mold half 21, 22, comprising at least one integrated hollow rail.

[0159] The lower lifting device 24 comprises counter-guide surfaces for the guide surfaces of the lower mold half 21. The counter-guide surfaces run from the upper conveyor belt device 7 in a conically tapering manner in the direction of the lower lifting device 24. They are designed in such a way that they engage with the guide surfaces of the mold half 21 as soon as the mold half 21 leaves the upper conveyor belt device 7 while being pushed in the direction of the lower lifting device 24. The counter-guide surfaces run towards the corresponding working position on the lower lifting device 24, ensuring an exact positioning of the mold 11 at the working position.

[0160] A third slide 27 is arranged opposite the pulper 3 on the other side of the upper conveyor belt device 7 to push the mold 11 onto the lower lifting device 24 of the pulper 3, wherein the upper mold half 22 of the mold 11 is simultaneously received by the upper lifting device 25.

[0161] A fourth slide 28 is arranged opposite the first slide 27 on the other side of the pulper 3 to push the mold 11 from the lower lifting device 24 of the pulper 3 back onto the upper conveyor belt device 7 after completion of the forming process.

[0162] The second transport section of the upper conveyor belt device 7 extends in the transport direction 12 from the position parallel to the pulper 3 up to a height just in front of the drying station 4.

[0163] In the second transport section, a dripping device (not shown) is provided between the pulper 3 and the drying station 4 for simultaneously dripping of one or more molded fiber articles 2. The dripping device is formed either by an area of the transport device 12, in particular the second transport section, or by a separate buffer area (not shown) decoupled from the transport device 12.

[0164] The second transport section is followed by a third transport section, whereby an automatic transfer of a mold 11 can take place. The third transport section runs parallel to the drying station 4 in such a way that it can provide the drying station 4 with the mold 11 and pick it up again from there.

[0165] The drying station 4 is arranged adjacent to the transport device 6 in such a way that a dead plate 31 is arranged approximately at the level of the upper conveyor belt device 7, on which the mold 11 rests during the drying process.

[0166] The drying station 4 comprises a drying device comprising a horizontally arranged capacitor plate 29 and a horizontally arranged ground plate 30. The capacitor plate 29 is connected to an RF generator 34, which can be used to apply an RF signal to the capacitor plate 29 by means of a waveguide 35. The ground plate 30 is connected to ground via a ground cable 36. The capacitor plates 29, 30 are designed to generate an electromagnetic field in the intermediate region of the two plates 29, 30, with which electromagnetic waves can be applied to the molded fiber article 2 in the mold 11 to dry the molded fiber article 2.

[0167] In this embodiment, it is possible to make the ground plate 30 vertically movable since only one movable ground cable 36 is guided to the plate 30.

[0168] The capacitor plate 29 is arranged in a stationary position, which means that the waveguide 35 can also be arranged in a stationary position. A reverse arrangement with a movable waveguide is also possible, but technically more difficult to implement.

[0169] The capacitor plate 29 comprises the dead plate 31, which rests on the capacitor plate 29 and is firmly connected to it. The ground plate 30 comprises plate 32, which is firmly connected to it. The plates 31, 32 are made of a non-electrically conductive material.

[0170] The ground plate 30 is connected to the first lifting device 33. In the present embodiment, the first lifting device 33 is a piston/cylinder unit.

[0171] The plates 31, 32 comprise at least one protruding profile rail, preferably with a latching means to receive the corresponding mold half 21, 22, comprising at least one integrated hollow rail. The profile rails are each made of a non-electrically conductive material. The profile rails are not only used for fixing fix the mold 11 in the drying station, but also to fill the cavities of the hollow rails on the mold halves 21, 22 to ensure a sealed surface between the plates 31, 32 of the capacitor plates 29, 30 and the corresponding mold halves 21, 22.

[0172] The dead plate 31 of the condenser plate 29 comprises counter-guide surfaces for the guide surfaces of the lower mold half 21. The counter-guide surfaces run from the upper conveyor belt device 7 in a conically tapering manner in the direction of the dead plate 31. They are designed in such a way that they engage with the guide surfaces of the mold half 21 as soon as the mold half 21 leaves the upper conveyor belt device 7 while being pushed in the direction of the dead plate 31. The counter-guide surfaces run towards the corresponding working position on the dead plate 31, ensuring an exact positioning of the 11 at the working position.

[0173] The radio frequency signal is preferably generated in a frequency range of at least 5 or 10 or 15 or 20 or 25 MHz up to not more than 50 or 45 or 40 or 35 or 30 MHz. The actual frequency used depends on which frequency is approved for industrial use. For example, In Germany it is allowed to use the frequency of 27.12 MHz. The amplitude can range from a few 100 volts to a few kV.

[0174] In another embodiment, the drying station 4 comprises the wave generator 34 for generating electromagnetic waves, the waveguide 35, the capacitor plate 29 and the ground plate 30.

[0175] The capacitor plate 29 and the ground plate 30 are made of metal.

[0176] By means of the wave generator 34, the electromagnetic waves can be introduced into the capacitor plate 29 via the waveguide 35.

[0177] The ground plate 30 is connected to ground via a ground cable 36.

[0178] The capacitor plate 29 and the ground plate 30 are arranged in such a way that they form a mold receiving area between themselves. The mold receiving area is designed to receive a mold 11 from an electrically conductive material (metal).

[0179] In this arrangement, the capacitor plate 29 and the first mold half 21 of the mold 11 form a first capacitor and the first mold half and the second mold half 22 of the mold 11 a second capacitor.

[0180] A first dielectric layer 31 is arranged between the capacitor plate 29 and the first mold half 21 of the mold 11. The first dielectric layer 31 is preferably fixed to the capacitor plate 29, but can also be arranged on a surface of the first mold half 21

[0181] A second dielectric layer is arranged between the first mold half 21 of the mold 11 and the second mold half 22 of the mold 11. The second dielectric layer is arranged equally in both mold halves 21, 22 or is arranged in only one of the two mold halves 21, 22.

[0182] Due to the dielectric layer between the capacitor plate 29 and the first mold half 21, one has a defined plate capacitor that reliably transmits the electromagnetic waves to the molded fiber article 2 and does not lead to uncontrolled welding or electrical flashovers between the metallic components of the assembly.

[0183] It is also possible to connect the waveguide 35 directly to the first mold half 21 of the mold 11, as well as to connect a ground cable 36 directly to the second mold half 22 of the mold 11, however, this is technically more difficult to implement.

[0184] The amplitude can also be gradually increased from a small initial value to a larger final value. The increase is preferably linear along a predetermined ramp. The ascending slope and/or the final value of the ramp can be varied depending on the water content in the molded fiber article 2.

[0185] In the embodiment example explained above, electromagnetic waves in the form of RF radiation are used. Instead of RF radiation, microwave radiation could also be applied. Microwave radiation can be generated very easily and cost-effectively by means of a magnetron. When microwave radiation is used, there is no use for a capacitor. Such an apparatus operating with microwave radiation is simpler and more cost-effective than an apparatus operating with RF radiation, however, has significant disadvantages due to the short wavelength and the inhomogeneous radiation distribution. The short wavelength of microwave radiation results in significant local differences in heat input. This can lead to undesirable non-uniform heating, especially in the case of larger molded fiber articles.

[0186] When microwave radiation is used instead of RF radiation, in the embodiment explained above, the plate capacitor can be replaced by a microwave tunnel to which microwaves are supplied by means of one or more magnetrons. A fifth slide 37 is arranged opposite the drying station 4 on the other side of the upper conveyor belt device 7 to push the mold 11 onto the dead plate 31 of the capacitor plate 29, wherein the upper mold half 22 of the mold 11 is simultaneously received by plate 32 of the upper capacitor plate 30.

[0187] A sixth slide 38 is arranged opposite the slide 37 on the other side of the drying station 4, to push the mold 11 back from the dead plate 31 of the lower capacitor plate 29 onto the upper conveyor belt device 7 after completion of the drying process.

[0188] The third transport section of the upper conveyor belt device 7 extends in the transport direction 12 from the position parallel to the drying station 4 to the first slide 17 after the demolding station 5. The third transport section runs parallel to the demolding station 5 in such a way that it can provide the mold 11 to the demolding station 5 and can pick it up again from there. In addition, a cooling station (not shown), which is arranged upstream of the demolding station 5, may be provided along the third transport section to rapidly cool the mold 11 and the molded fiber article 2. By the use of electromagnetic waves, the mold 11 and the molded fiber article 2 were heated up to a high degree.

[0189] A cooling station is an optional workstation. If active cooling is provided, the cooling station makes the entire process more efficient.

[0190] The cooling station comprises a cooling device, which is at least one air blower to quickly cool the mold 11 and the molded fiber article 2.

[0191] The cooling station is preferably a long tunnel along the third transport section of the upper conveyor belt device 7, starting shortly after the drying station 4 and ends shortly before the demolding station 5 and comprising several air blowers to gradually cool the mold 11 and the molded fiber article 2 during passage through the tunnel.

[0192] After the cooling station, the demolding station 5 follows to open the mold 11 and remove the molded fiber article 2.

[0193] The demolding station 5 is arranged adjacent to the transport device 6 in such a way that a demolding surface 39 is arranged approximately at the level of the upper conveyor belt device 7, on which the mold 11 rests during the demolding process.

[0194] The demolding station 5 comprises a second lifting device 40, which is vertically movable and in the present embodiment is a piston/cylinder unit.

[0195] The demolding station 5 has a gripping device 42, which is connected to a third lifting device 41. In the present embodiment, the third lifting device 41 is designed as a piston/cylinder unit. The third lifting device 41 and the gripping device 42 can thus be moved in the vertical direction.

[0196] The gripping device 42 comprises a gripper 43, which is designed to grip the finished molded fiber article 2 from the opened mold 11.

[0197] The second lifting device 40 and the gripping device 42 are each attached to a rail 45 by means of a carriage 44, 50 and can thus be moved horizontally.

[0198] The demolding surface 39, and the second lifting device 40 comprise at least one protruding profile rail, preferably with a latching means to receive the corresponding mold half 21, 22, comprising at least one integrated hollow rail.

[0199] The demolding surface 39 comprises counter-guide surfaces for the guide surfaces of the lower mold half 21. The counter-guide surfaces run from the upper conveyor belt device 7 in a conically tapering manner in the direction of the demolding surface 39. They are designed in such a way that they engage with the guide surfaces of the lower mold half 21 as soon as the mold half 21 leaves the upper conveyor belt device 7 while being pushed in the direction of the demolding surface 39. The counter-guide surfaces run towards the corresponding working position on the demolding surface 39, ensuring an exact positioning of the mold 11 at the working position.

[0200] A seventh slide 46 is arranged opposite the demolding station 5 on the other side of the upper conveyor belt device 7 to push the mold 11 onto the demolding surface 39 of the demolding station 5, wherein the upper mold half 22 of the mold 11 is simultaneously received by the second lifting device 40.

[0201] An eighth slide 47 is arranged opposite the slide 46 on the other side of the demolding station 5, to push the mold 11 back from the demolding surface 39 of the demolding station 5 onto the upper conveyor belt device 7 after completion of the demolding process.

[0202] Preferably, a cleaning station 48 is provided along the lower conveyor belt device 8 and is configured to clean the mold 11 prior to reuse.

[0203] The cleaning station 48 comprises a cleaning device 49, which can be a water shower that rinses the mold 11.

[0204] A process of the apparatus 1 described above for producing a molded fiber article 2 is explained below. In the following, the process is described using the throughput of a mold. However, it is provided that the process can be used to process several molds in succession and/or in parallel at the workstations.

[0205] The mold 11 is pushed by means of the first slide 19 from the movable platform 15 of the first lifting device 9 to the starting position 13, which is on the upper conveyor belt device 7 in front of the pulper 3.

[0206] The upper conveyor belt device 7 transports the mold 11 up to the height of the pulper 3.

[0207] The mold 11 is pushed onto the lower lifting device 24 of the pulper 3 by means of the third slide 27. The upper mold half 22 of the mold 11 is simultaneously picked up by the upper lifting device 25.

[0208] The integrated profile rails of the lower mold half 21 or the upper mold half 22 engage in the corresponding counter profiles, preferably with a latching means, of the lower lifting device 24 or the upper lifting device 25 and fix the mold halves 21, 22.

[0209] The lower lifting device 24 lowers the lower mold half 21 into the container 23 so that the lower mold half 21 is below the level of the fibrous material suspension 26, i.e., the lower mold half 21 is then completely immersed in the fibrous material suspension and fills with fibrous material suspension. In FIG. 1, the lower lifting device 24 is configured in such a way that the lifting device 24 extends through a bottom of the container 23. In practice, however, it is often easier to arrange the lower lifting device 24 completely within the container 23, as there is then no through-hole to seal.

[0210] The upper and lower mold half 22, 21 are moved together in such a way that they delimit between them a mold interior space, which corresponds approximately to the molded fiber article 2 to be produced.

[0211] The two mold halves 21, 22 can be moved together in pulper 3 below the level of the fibrous material suspension, so that the entire mold interior space is filled with the fibrous material suspension. Then the mold 11 is raised via the level to approximately the height of the upper conveyor belt device 7.

[0212] After lifting the forming tool 11 with the fibrous material suspension above the level of the container 23 of the pulper 3, the moisture content of the molded fiber article 2 quickly reduces to a value of not more than 80% by weight or not more than 70% by weight or not more than 60% by weight.

[0213] The two lifting devices 24, 25 press the two mold halves 21, 22 together in such a way that water is pressed out of the fibrous material suspension located in the mold interior space of the mold 11 and the fibrous material suspension is formed into the molded fiber article 2.

[0214] After forming the molded fiber article 2, the mold 11 is pushed back from the lower lifting device 24 of the pulper 3 onto the upper conveyor belt device 7 by means of the fourth slide 28.

[0215] When the wet fibrous material suspension is compressed during forming in the mold 11, the outlet holes of the mold 11 are plugged and joints are sealed. As a result, air con no longer enter the inside of the mold 11. As a result, the mold halves 21, 22 adhere to each other and a large force is required to separate the mold halves 21, 22. This connection can be so tight that locking is no longer required to ensure that the mold halves 21, 22 are not accidentally disconnected. In this case, it is then not necessary to use the locking or latching device on the mold 11.

[0216] The upper conveyor belt device 7 transports the mold 11 further from the pulper 3 to the dripping device. In the dripping device, the mold 11 drips off until the molded fiber article 2 has reached a predetermined moisture content and is suitable for drying by means of electromagnetic waves in the drying station 4.

[0217] Here it is possible to form several molded fiber articles 2 directly one after the other and/or to dry them directly one after the other, whereby several molds 11 with the molded fiber articles 2 contained therein can be held 2 in one step for dripping until sufficient moisture has escaped from the molds 11. As soon as a predetermined degree of dryness has been reached, a mold 11 with a molded fiber article 2 can be fed to the drying station 4.

[0218] After pressing the fibrous material suspension in the mold 11 and dripping, the molded fiber article still has a moisture content of not more than 30% by weight or not more than 25% by weight or not more than 20% by weight. From the dripping device, the conveyor belt device 7 transports the mold to the drying station 4, which has a drying device.

[0219] The mold 11 is pushed onto the deposit area 31 of the drying device by means of the fifth slide 37.

[0220] The ground plate 30 of the drying device is moved onto the upper mold half 22 of the mold 11 by means of the first lifting device 33. The lower mold half 21 of the mold 11 is in contact with the capacitor plate 29 via the deposit area 31.

[0221] The capacitor plate 29 and the ground plate 30 are configured to generate a strong alternating electromagnetic field between them by means of the RF generator 34, which is connected to the capacitor plate 29, and thus to transmit electromagnetic waves in the form of RF waves to the molded fiber article 2.

[0222] The RF waves are absorbed to a considerable extent by the water present in the molded fiber article 2. The water is heated and evaporates from the molded fiber article 2, causing it to form-dry and cure.

[0223] The use of RF waves makes it is possible to heat the molded fiber article 2 quickly from the inside out in a short time, thereby achieving the desired degree of dryness correspondingly. However, it would also be possible to heat the mold 11 directly via a heating device and thus indirectly mold-dry the molded fiber article 2. However, this is significantly less efficient than heating the molded fiber article 2 directly using electromagnetic waves.

[0224] In addition to RF waves, microwaves can also be used as electromagnetic waves. However, in contrast to microwaves, RF waves have the advantage that they heat the entire molded fiber article 2 uniformly at once due to their longer wavelength. With microwaves, the heat input is locally limited, and they are therefore more suitable for smaller molded fiber articles 2.

[0225] The mold drying of the molded fiber articles 2 by means of the electromagnetic waves reduces the moisture content of the molded fiber article 2 to a value of not more than 10% by weight or not more than 7.5% by weight or not more than 5% by weight. In another embodiment, a process for drying the molded fiber article 2 in the drying station 4 is provided, in which a mold 11 formed of an electrically conductive material (metal) and formed of a first mold half 21 and a second mold half 22, is moved into a mold receiving area between the capacitor plate 29 and the ground plate 30.

[0226] Electromagnetic waves are generated by the wave generator 34 and introduced into the capacitor plate 29 via the waveguide 35. The ground plate 30 is connected to ground via a ground cable 36.

[0227] The first mold half 21 of the mold 11 is in contact with the capacitor plate 29 via a first dielectric layer 31. The first mold half 21 and the capacitor plate 29 form a first capacitor.

[0228] The first mold half 21 of the mold 11 and the second mold half 21 form a second capacitor.

[0229] The electromagnetic waves are transmitted to the molded fiber article 2 via the capacitor plate 29 and the first mold half 21 of the mold 11 and dry the molded fiber article 2.

[0230] After the drying process, the ground plate 30 of the drying device is moved upwards away from the upper mold half 22 of the mold 11 by means of the first lifting device 33.

[0231] The mold 11 is pushed back onto the upper conveyor belt device 7 by means of the sixth slide 38 from the depositing surface 31 of the drying device.

[0232] The upper conveyor belt device 7 transports the mold 11 further from the drying station 4 to the cooling station. The cooling station is an optional workstation. If active cooling is provided, a cooling station makes the whole process more efficient.

[0233] The cooling station is arranged so that the mold 11 with the molded fiber article 2 can remain on the upper conveyor belt device 7 can remain and be cooled there.

[0234] The mold 11 with the molded fiber article 2 is cooled by one or more air blowers of the cooling station as it moves through the cooling station.

[0235] In addition to the cooling process, the mold 11 is simultaneously conveyed further to the demolding station 5. The upper conveyor belt device 7 transports the mold 11 to the level of the demolding surface 39.

[0236] The mold 11 is pushed onto the demolding surface 39 of the demolding station 5 by means of the seventh slide. The upper mold half 22 of the mold 11 is simultaneously picked up by the second lifting device 40.

[0237] The integrated profile rails of the lower mold half 21 or the upper mold half 22 engage in the corresponding counter profiles, preferably with a latching means, of the demolding surface 39 or the lifting device 40 and fix the mold halves 21, 22.

[0238] By lifting the upper mold half 22 by means of the second lifting device 40, the mold 11 is opened and the molded fiber article 2 is exposed.

[0239] The second lifting device 40 and the gripping device 42 are moved in the rail 45 by means of the carriages 44, 50 in such a way that the second lifting device 40 moves away to the side with the upper mold half 22 and the gripping device 42 stops above the molded fiber article 2 and the lower mold half 21.

[0240] By lowering the gripping device 42 by means of the third lifting device 41 and closing the gripper 43, the molded fiber article 2 can be picked up. By raising and lowering the gripping device 42 and moving the carriage 44 in the rail 45, the molded fiber article 2 can be deposited on the depositing surface 51.

[0241] Synchronously, the upper mold half 22 can be reunited with the lower mold half 40 by raising and lowering the second lifting device 21 accordingly and moving the carriage 50 in the rail 45.

[0242] After the demolding process, the mold 11 is pushed by means of the eighth slide from the demolding surface 39 of the demolding station 5 back onto the upper conveyor belt device 7.

[0243] The upper conveyor belt device 7 transports the mold 11 further from the demolding station 5 to the first slide 17.

[0244] The mold 11 is conveyed from the upper conveyor belt device 7 to the first slide 17 and from there it is automatically moved by means of the passive roller conveyor of the slide 17 to the second movable platform 16 of the second lifting device 10.

[0245] The second lifting device 10 conveys the mold 11 downwards to the level of the lower conveyor belt device 8, where the mold 11 is pushed by means of the second slide 20 from the movable platform 16 to the lower conveyor belt device 8 and simultaneously in the direction of the cleaning station 48.

[0246] The cleaning device 49, which can be a water shower, cleans the mold 11 as it passes through the cleaning station 48 on the lower conveyor belt device 8.

[0247] After completion of cleaning, the mold 11 is transported to the second slide 18 by the lower conveyor belt device 8 and conveyed from the lower conveyor belt device 8 to the second slide 18. From there, the mold 11 is automatically moved by means of the passive roller conveyor of the second slide 18 onto the movable platform 15 of the first lifting device 9.

[0248] The first lifting device 9 conveys the mold 11 upwards to the height of the upper conveyor belt device 7, where it is then ready for the next forming process.

[0249] In the embodiment explained above, the mold 11 is lowered into the container 23 and retracted there to receive the fibrous material suspension in the mold interior space. It is also possible to arrange the lower mold half 21 stationary above the container 23 and to pump the fibrous material suspension from below through the lower mold half 21 into the mold interior space limited by the mold 11 by means of a pump. Water can then escape again from the mold interior space through the lower mold half 21 and drip back into the container 23.

[0250] In order to prevent excessive dilution of the fibrous material suspension in the container 23 in the long term, it may also be advisable to drain off the water from the mold 11 so that it does not enter the container 23.

[0251] In the embodiment explained above, the capacitor plate 29 and the ground plate 30 are designed in such a way that the capacitor plate 29 is in contact with the lower mold half 21 and the ground plate is moved onto the upper mold half 22 in an interference fit. In principle, the two capacitor plates 29, 30 can also be moved laterally against the two mold halves 21, 22.

[0252] In the embodiment described above, it is primarily the cycle rate of the cooling station that determines how many molded fiber articles 2 are produced per time unit and thus the efficiency of the complete process. The cooling of the molded fiber articles 2 is the most time-consuming step of the process. The molding, the drying and the demolding of the molded fiber articles 2, on the other hand, is faster.

[0253] A circulation device can be provided at the pulper 3, which runs independently of the upper conveyor belt device 7 and is designed to receive several molds 11 after the forming of the molded fiber article 2. Further, this allows additional molded fiber articles 2 to be formed, while others are still in the drying station 4. The circulation device can be an additional conveyor belt that moves the molds 11 in a circuit. In this case, the speed of the conveyor belt can be set variably and independently of the upper conveyor belt device 7 of the transport device 6. The additional conveyor belt can be designed as a grid so that water can drip through it into a collection container. The circulating device can also be a paternoster

[0254] that moves the forming tools 11 in a circle. A possible and inexpensive alternative to the circulation device is a long conveyor belt section between pulper 3 and drying station 4.

[0255] The cooling station can be provided as a circulating device that runs independently of the upper conveyor belt device 7 and is designed to receive several molds 11 after the drying of the molded fiber article 2 to cool the molded fiber articles 2 in the air. Further, this allows additional molded fiber articles 2 to be dried, while others are still in the cooling station. The circulation device can be another conveyor belt that moves the molds 11 in a circuit. In this case, the speed of the conveyor belt can be set variably and independently of the upper conveyor belt device 7 of the transport device 6. The circulation device can also be a paternoster that moves the molds 11 in a circle. A possible and inexpensive alternative to the circulation device is a long conveyor belt section between drying station and demolding station 5. The cooling station can be a tunnel comprising several air blowers

[0256] that dries the molds as they pass through. As a result, the upper conveyor belt device 7 can continue to run continuously.

LIST OF REFERENCE NUMBERS

[0257] 1 apparatus [0258] 2 molded fiber article [0259] 3 pulper [0260] 4 drying station [0261] 5 demolding station [0262] 6 transport equipment [0263] 7 upper conveyor belt device [0264] 8 lower conveyor belt device [0265] 9 first lifting device [0266] 10 second lifting device [0267] 11 mold [0268] 12 transport direction [0269] 13 starting position [0270] 14 reverse direction [0271] 15 first moving platform [0272] 16 second moving platform [0273] 17 first gravity chute [0274] 18 second gravity chute [0275] 19 first slide [0276] 20 second slide [0277] 21 lower mold half/first mold half [0278] 22 upper mold half/second mold half [0279] 23 containers [0280] 24 lower lifting device [0281] 25 upper lifting device [0282] 26 mirror of the pulp suspension [0283] 27 third slide [0284] 28 fourth slide [0285] 29 capacitor plate [0286] 30 ground plate [0287] 31 dead plate/first dielectric layer [0288] 32 plate [0289] 33 first lifting device [0290] 34 RF generator [0291] 35 waveguide [0292] 36 ground cable [0293] 37 fifth slide [0294] 38 sixth slide [0295] 39 demolding surface [0296] 40 second lifting device [0297] 41 third lifting device [0298] 42 gripping device [0299] 43 gripper [0300] 44 first slide [0301] 45 rail [0302] 46 seventh slide [0303] 47 eighth slide [0304] 48 cleaning station [0305] 49 cleaning device [0306] 50 second carriage [0307] 51 storage space