Method and apparatus for producing a fiber moulding

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.

Description

[0001] The present invention relates to a method and a device for manufacturing a fiber casting.

[0002] Fiber castings, also known as fiber molded parts, are produced by dissolving fibers in a pulper to create a fiber suspension, which is then formed in a mold. The fiber casting is then dried under heat, causing the fibers to bond together to form a solid object.

[0003] The fibers used are primarily cellulose fibers from recycled paper or virgin fibers. However, other fibers, especially natural ones, can also be used, provided they are recyclable and / or compostable. Hemp, for example, is one such fiber.

[0004] Fiber castings have gained significant importance in the packaging industry in recent years. This is partly due to the fact that fiber castings are usually biodegradable and therefore easy and inexpensive to dispose of. Furthermore, fiber castings can be recycled cost-effectively by shredding them into individual fibers and forming them into a new fiber casting. Fiber castings are also space-saving, stable, and shock-absorbing. They can be manufactured in any three-dimensional shape, allowing them to be adapted to a wide variety of products. Fiber castings can also be made flame-retardant and / or grease- and water-repellent.

[0005] In a conventional process for manufacturing a fiber casting, the fibers are dissolved in water in a pulper to form a fiber suspension. This fiber suspension forms a slurry that is molded into a fiber casting in a mold. The mold has at least one half that defines the mold cavity with a grid. This mold is called a grid mold. The grid mold has numerous openings through which water can escape from the mold cavity. The molding step of the fiber suspension thus serves not only to shape the part but also to dry it. A fiber casting demolded from the mold is then dried and cured in a stream of hot air.

[0006] It is also known that fiber castings are dried using electromagnetic waves during and / or after molding. RF or microwave radiation is frequently used for this purpose.

[0007] A fiber casting produced in this way can then be fed to an embossing and / or stamping tool by further shaping the fiber casting.

[0008] Fiber castings are mass-produced items manufactured in large quantities for packaging goods in the packaging industry. Therefore, there is a significant need to improve the process to increase throughput and / or reduce costs.

[0009] German patent application GB 2 413 301 A relates to a method and apparatus for producing a molded part made of cellulose, in which radio waves are used for forming and drying the part. The starting material is a fibrous suspension, which is subsequently pressed and dried. Furthermore, the apparatus of D1 consists of two metal mold halves, which can serve as electrodes for generating an RF field and are connected to an external RF generator. The fibrous suspension is located between the two mold halves, which are designed to allow water or water vapor to escape from the molds. A dielectric layer, acting as an electrical insulator and protecting the fibrous suspension from direct current flow, is located at the interface between the fibrous suspension and the mold halves.

[0010] US Patent 2019 / 0169800 A1 discloses a method and apparatus for manufacturing a molded part made of cellulose, in particular for manufacturing a bottle made of cellulose. The starting material is a suspension of fibrous material. The molding tool is a porous mold consisting of at least two separable parts, which may be made of metal. The molded part is dried in a microwave drying chamber.

[0011] CN 205 000 197 U discloses an apparatus and a method for forming and drying a fibrous product, using microwaves for drying. The apparatus consists of two outer molds enclosing two inner non-metallic molds. The wet fibrous material is placed between the two inner molds and pressed. Simultaneous drying is carried out using microwaves, and the moisture escapes the apparatus through holes within the inner molds.

[0012] German patent DE 10 2019 116 134 A1 describes a method and a device for manufacturing a fiber casting. In this process, fibrous materials are dissolved in water to form a fiber suspension, the fiber suspension is formed into a fiber casting in a mold, and the fiber suspension is then dried. The forming and / or drying is carried out by applying heat using electromagnetic waves. The electromagnetic waves can be microwaves or RF waves.

[0013] The invention is based on the objective of creating a method or device for producing a fiber casting, with which fiber castings can be produced with high throughput and at low cost.

[0014] Furthermore, the invention is based on the objective of creating a method for producing a fiber casting that is reliable, safe and stable.

[0015] The problem is solved by the subject matter of the independent patent claims. Advantageous embodiments of the invention are specified in the respective dependent claims.

[0016] A method for producing a fiber casting according to the present invention comprises the following steps: Dissolving fibrous materials in water to form a fibrous suspension in a pulper, dehumidifying the fibrous suspension by pressing it into a fibrous casting in a mold and / or drying the fibrous casting by applying heat in the mold and demolding the fibrous casting from the mold.

[0017] In mold drying of the fiber casting, the fiber casting is subjected to electromagnetic waves in such a way that it dries in the mold until a moisture content of the fiber casting of a maximum of 10 wt.% or a maximum of 7.5 wt.% or a maximum of 5 wt.% is reached.

[0018] The process is characterized by the fact that the fiber casting is dried in a drying station and demolded from the mold in a demolding station, with the pulper, the drying station and the demolding station forming workstations.

[0019] In contrast to the method known from US 2019 / 0169800 A1, the present invention dries the fiber casting in the mold to a moisture content of no more than 10% by weight. In US 2019 / 0169800 A1, the fiber casting is also dried to a low moisture content, but in that method, the fiber casting is removed from the mold before drying.

[0020] Drying to such a low moisture content of a maximum of 10% by weight in the mold ensures that the fiber casting precisely replicates the shape of the mold. For example, if the mold has a smooth surface, the fiber casting will have a correspondingly smooth surface. Such smooth fiber castings are perceived as high-quality products.

[0021] By using electromagnetic waves, it is possible to quickly heat the fiber casting from the inside out in a short time, thus achieving the desired degree of dryness rapidly. In principle, one could also heat the mold and thus indirectly dry the fiber casting. However, this is considerably slower than directly heating the fiber casting using electromagnetic waves.

[0022] Microwaves and RF radiation can both be used as electromagnetic waves. RF radiation has the advantage that, due to its long wavelength, the entire fiber casting can be heated evenly in one go. With microwaves, the heat input is locally limited, so the microwave beam must be moved relative to the fiber casting during drying. This slows down the drying process and can also lead to uneven heating and thus uneven drying.

[0023] Achieving a moisture content of up to 5% by weight in the fiber casting through an active drying process allows for rapid further processing of the fiber casting after drying. This enables, on the one hand, increased throughput for the production of fiber castings and, on the other hand, saves space that would otherwise be required for further drying steps and / or intermediate storage. Both of these factors contribute to a more efficient overall production of fiber castings.

[0024] The pressing of the fiber suspension into the mold to form the fiber casting takes place in the pulper, ensuring that the mold is completely filled with fiber suspension during pressing. This allows for the production of fiber castings with a predetermined density and surface contour.

[0025] When drying using electromagnetic waves, drying times of less than one minute per fiber casting can be achieved.

[0026] By combining rapid drying using electromagnetic waves with drying to such a low moisture content of up to 5 wt%, fiber castings can be produced that exhibit a smooth surface, improved surface quality, and precise final dimensions. Compared to previously known fiber castings, these mold-dried fiber castings are of particularly high quality and thus offer new application possibilities, such as the packaging of high-quality end products.

[0027] The inventors of the present invention have recognized that rapid drying of a fiber casting by means of electromagnetic waves and simultaneously effective drying in conjunction with a low moisture content of the fiber casting is possible, thereby achieving a high quality of the fiber casting.

[0028] Microwave radiation is particularly suitable for smaller fiber castings. Microwaves can be generated using very inexpensive microwave generators called magnetrons.

[0029] Water is an excellent absorber of electromagnetic waves. This allows the fiber suspension to be heated directly. This enables the fiber suspension to be heated within the mold without the need to preheat the mold itself. The heat transfer to the fiber casting is therefore significantly more efficient than with indirect heating methods such as hot air. This considerably accelerates the curing of the fiber suspension within the mold.

[0030] The demolded fiber casting can also be heated directly by applying heat using electromagnetic waves.

[0031] The more moisture the fiber casting contains, the more strongly it absorbs electromagnetic waves. Therefore, the effect is greater the more moisture the fiber casting contains. This results in a certain self-regulation of the heating and drying process.

[0032] By heating the fiber suspension or the demolded fiber casting using electromagnetic waves, the production process of a fiber casting can be accelerated, while simultaneously reducing the required energy expenditure.

[0033] Since fiber castings are generally produced in large quantities, even a slight acceleration of a single manufacturing step represents a significant increase in the overall production throughput.

[0034] The large-scale production of fiber castings also means that the energy savings in the production of a single fiber casting are accumulated across the large number of parts, resulting in a significant overall reduction in energy consumption. This is of paramount importance for fiber castings, as they are accepted by the market due to their environmental advantages over other packaging materials, particularly plastic packaging. The environmental impact assessment of fiber castings also includes the energy consumption involved in their production. Reducing energy consumption translates into greater market acceptance of fiber castings.

[0035] After the fiber suspension has been introduced into the mold, the fiber casting can have a maximum moisture content of 80 wt.%, 70 wt.%, or 60 wt.%.

[0036] After dehumidifying the fiber suspension in the mold, the fiber casting can have a maximum moisture content of 30 wt.%, 25 wt.%, or 20 wt.%.

[0037] The mold can be transported from the pulper to the drying station and to the demolding station by means of a transport device.

[0038] When manufacturing a fiber casting using electromagnetic waves to dry the fiber casting, the fiber casting should be allowed to drip dry for a predetermined time after forming in the pulper, as excessive moisture content can cause problems when heating with electromagnetic waves.

[0039] By transporting the mold from the pulper to the drying station via a conveyor system, it is possible to decouple the molding and drying steps of the fiber casting both temporally and spatially. This provides a buffer to allow the fiber casting sufficient time to drain.

[0040] This makes it possible to mold and / or dry several fiber castings in immediate succession, whereby multiple molds with their fiber castings can be held for draining in a single step until sufficient moisture has escaped from the molds. Once a predetermined degree of dryness is reached, a mold with a fiber casting can then be transferred to the drying station.

[0041] Accordingly, a draining step of the fiber casting within the mold can be provided between the forming and drying steps. Preferably, this step can be performed in a buffer zone for the simultaneous draining of two or more fiber castings. Additionally and / or alternatively, this step can also be performed on the transport system along the path from the pulper to the drying station.

[0042] In this way, the process for manufacturing a fiber casting can be carried out efficiently and automatically.

[0043] Through appropriate advantageous designs, which will be described in more detail below, several molds and / or several workstations, in particular pulpers and drying stations, can be used simultaneously in the manufacturing process.

[0044] This allows the device used in the process to be used efficiently, and at the same time ensures that there is enough time after the two mold halves have been pressed together for the water to escape.

[0045] Furthermore, this method allows the drying of the fiber casting by pressing and heating by electromagnetic waves to be carried out in one tool.

[0046] Furthermore, the process can include a step of cooling the fiber casting within the mold. This ensures sufficient cooling time after heating.

[0047] The molding tool can be detachably attached to the pulper and, after forming a fiber casting, automatically detached and transported to the next workstation.

[0048] In particular, it may be provided that one or more forming tools are releasably attached to at least one of the workstations and / or to the transport device, so that after processing at at least one of the workstations, one or more forming tools are preferably automatically coupled or uncoupled into a workstation and / or the transport device accordingly.

[0049] The spatial separation of the pulper and the drying station makes it possible to drain the mold and reduce the moisture present in the mold and on the fiber casting. This prevents electrical arcing during drying with electromagnetic waves, thus making the process more reliable, safer, and more stable.

[0050] By physically separating the work steps, they can be carried out independently of each other. This makes it possible to decouple the processing steps of forming the fiber casting in the pulper and drying in the drying station.

[0051] In this way, any number of molds can be kept between the molding and drying stages. Each mold, containing a moist, freshly molded fiber casting, can drain for any length of time after molding before being dried in the drying station without affecting the overall process throughput. Since draining takes longer than molding the fiber castings, additional parts can be molded while others are waiting at the drying station.

[0052] The mold is preferably detached from the pulper after each molding process and, together with the respective fiber casting, passes through the entire process path. The mold can therefore be designed as a separately manageable unit. This makes it easy to integrate a different type of mold, designed for molding other fiber castings, into the process path and / or to produce different molds and thus different fiber castings using the same method.

[0053] The mold halves can preferably be designed such that, after forming in the pulper, they are connected to each other by means of a suitable locking device through force, friction and / or form locking.

[0054] Because the mold halves are held together by means of a suitable locking device, they form a stable unit that can be transported independently with the transport device.

[0055] During the forming process, when the wet fiber suspension is compressed in the mold, the mold's outlet holes become blocked and the joints are sealed. This prevents air from entering the mold. As a result, the mold halves adhere to each other, requiring considerable force to separate them. This bond alone is sufficient for transport on the conveyor system. This bond can be further strengthened by locking mechanisms. The conveyor system preferably transports one or more molds along a circuit in a single direction.

[0056] These two embodiments make it possible to operate multiple tools in a closed loop. This allows the tools to be temporarily stored independently of the cycle frequency of the press and the RF station, in order to allow water to drain off and / or to cool down after RF heating.

[0057] For example, 5, 10, 15, 20, or 25 molds can be operated simultaneously in a cycle.

[0058] The drying station and / or a cooling station and / or a demolding station can be arranged in the transport direction along the transport device and can each accommodate at least one mold tool for processing, either successively and / or simultaneously.

[0059] In particular, several molds can be accommodated simultaneously at the cooling station to cool gradually. Buffers for holding multiple molds can be provided upstream of each workstation to improve temporal decoupling and achieve maximum throughput at each workstation.

[0060] The individual workstations, in particular the drying station, the cooling station and the demolding station, can each have several parallel operating devices that can simultaneously accommodate at least one mold tool for processing.

[0061] In particular, the use of several parallel drying stations within the drying station enables continuous utilization of all workstations and a constant throughput of finished fiber castings. This also allows for the production of fiber castings of varying sizes, where the molding process takes the same amount of time, but the drying time increases with size.

[0062] By using multiple molds in a cycle, the work steps are further decoupled in time. With a sufficient number of molds, it is possible to ensure that all workstations are continuously utilized, even though the individual work steps require varying amounts of time. The work steps of the individual molds can therefore be carried out in parallel or sequentially, depending on the number of workstations.

[0063] In particular, a forming tool can be arranged between at least two condenser plates of the drying station, whereby the electromagnetic waves are applied to the forming tool via the condenser plates.

[0064] Furthermore, it is preferably provided that a forming tool is arranged between at least two condenser plates of the drying station, wherein the electromagnetic waves are applied to the forming tool via the condenser plates.

[0065] In the drying station, electromagnetic waves can be generated by a wave generator and introduced via a waveguide into a capacitor plate with a mold tool receiving area.

[0066] According to a first embodiment, it can be provided that the capacitor plate has a first dielectric layer in the mold receiving area, and a mold made of an electrically conductive material (metal) is arranged in the mold receiving area, such that the capacitor plate forms a first capacitor with a first mold half of the mold, and wherein a second dielectric layer is provided in a contact area between the first mold half and a second mold half, such that the first mold half and the second mold half form a second capacitor.

[0067] The second mold half is connected to ground. Preferably, the second mold half is in contact with a grounding plate that is also connected to ground.

[0068] The first capacitor formed by the capacitor plate (first capacitor plate) and the first half of the mold (second capacitor plate) can be called the coupling capacitor. The second capacitor formed by the first half of the mold (second capacitor plate) and the second half of the mold (third capacitor plate) is referred to below as the mold capacitor.

[0069] The use of the capacitor plate and the grounding plate creates a uniform electric field between the first and second mold halves. This is a prerequisite for uniform heating of the fiber casting within the mold. According to the first embodiment, the mold, or at least one mold half, is made of an electrically conductive material, preferably a metal.

[0070] In principle, it is also possible to couple the waveguide directly to the first half of the mold, as well as to couple a grounding cable directly to the second half of the mold, however, a detachable connection of a waveguide is technically difficult to implement.

[0071] The capacitive coupling of the waveguide to the electrically conductive mold half via the coupling capacitor is easily implemented and results in precisely repeatable transmission conditions. The upper mold half forms a capacitor plate of the coupling capacitor, and the dielectric is positioned between them. This allows the mold to be easily replaced in the drying station.

[0072] According to a second embodiment, it can be provided that the forming tool is directly received between the capacitor plate and the grounding plate, wherein the forming tool is made of an electrically insulating material, so that the capacitor plate and the grounding plate form a capacitor.

[0073] In this arrangement, the capacitor plate (first capacitor plate) and the grounding plate (second capacitor plate) form a single capacitor.

[0074] The mold can be made entirely of plastic or another dielectric material and is positioned between the two capacitor plates of the drying station.

[0075] According to a third embodiment, it can be provided that the capacitor plate has a first dielectric layer in the mold receiving area, and a mold consisting of two mold halves is arranged in the mold receiving area, wherein the first mold half is made of metal and the second mold half is made of a dielectric material, so that the capacitor plate forms a first capacitor with the first mold half of the mold, and the first mold half forms a second capacitor with the grounding plate.

[0076] According to a fourth embodiment, it can be provided that a mold consisting of two mold halves is arranged in the mold receiving area, wherein the first mold half is made of a dielectric material and the second mold half is made of metal, so that the capacitor plate forms a capacitor with the second mold half of the mold.

[0077] These four embodiments make it possible to operate multiple tools in a closed loop. This allows the tools to be temporarily stored independently of the pulper and drying station cycle frequency, to allow water to drain off and / or to cool down after RF heating.

[0078] This allows the system to be used efficiently, while simultaneously ensuring sufficient time for the water to drain out after the mold halves are pressed together, and allowing enough time for cooling after heating. This process enables the drying of the fiber casting in a single mold by pressing and heating with RF.

[0079] Simultaneously with the application of electromagnetic waves, the fiber casting can be compressed in the mold.

[0080] A binder can be added to the fiber casting. The binder can be mixed into the fiber suspension or sprayed onto the molded but not yet dried fiber casting. The fiber casting can also be produced completely without a binder.

[0081] According to a further aspect of the present invention, a device for producing a fiber casting is provided. This device comprises a pulper for dissolving fibers in water to form a fiber suspension, a mold with two mold halves for dehumidifying the fiber suspension by pressing it into a fiber casting, a drying station for drying the fiber casting by applying heat in the mold, and a demolding station for demolding the fiber casting from the mold.

[0082] The drying station comprises a wave generator for electromagnetic waves and a control unit configured such that the fiber casting is dried by means of electromagnetic waves to a maximum moisture content of 10 wt.%, 7.5 wt.%, or 5 wt.%. The device is characterized by the inclusion of a transport device for conveying the mold from the pulper to the drying station and the demolding station, the pulper, the drying station, and the demolding station constituting workstations.

[0083] The molding tool can have a temperature sensor and / or a humidity sensor, wherein the control device for controlling the wave generator can be designed such that energy is supplied to the molding tool by means of electromagnetic waves according to the measured temperature and / or the measured humidity.

[0084] In such a device for manufacturing fiber castings, fiber castings of varying shapes and sizes are generally produced during manufacturing. Accordingly, different molds are used. Depending on the size of the fiber casting, the parameters that must be set to achieve the predetermined moisture content change. These parameters include, for example, the duration for which electromagnetic waves must be introduced into the fiber casting or the energy required for drying the fiber casting.

[0085] The control unit is provided for controlling these parameters. The control unit is connected to the wave generator and the temperature sensor and / or the humidity sensor. Based on the values ​​determined by the temperature sensor or humidity sensor, the control unit controls the aforementioned parameters for drying the fiber casting. The temperature sensor or humidity sensor is preferably permanently integrated into the mold so that it is automatically connected to the control unit and its data can be read when the mold is placed in the drying station.

[0086] The temperature sensor is preferably a light guide sensor.

[0087] The humidity sensor can, for example, be an electrode pair sensor that measures humidity based on electrical resistance.

[0088] It is also possible for the control unit to perform the drying process for a predetermined time. This duration is determined empirically for each mold and the respective manufacturing process. This method also allows the desired drying quality to be achieved in the mold. However, the duration of exposure to electromagnetic waves must be determined separately for each mold.

[0089] The advantages of the device according to the invention correspond to the advantages of the method according to the invention, wherein the device has the corresponding technical features for carrying out the above-described process steps.

[0090] Preferably, a draining device for the simultaneous draining of one or more fiber castings can be provided between the pulper and the drying station, which is formed either by a section of the transport device or by a separate buffer section decoupled from the transport device.

[0091] In addition, a cooling station can be provided for cooling the fiber casting in the mold.

[0092] The mold halves are preferably detachably attached to the pulper and can be automatically opened and closed there.

[0093] At least one of the mold halves may have openings for water to escape and / or be made of a porous material.

[0094] The mold can be made of plastic or resin, or of metal.

[0095] The mold is preferably made of a material that is essentially transparent to the applied electromagnetic waves, such as high molecular weight polyethylene (PE), polyetheretherketone (PEEK) or another non-polar plastic material.

[0096] The drying station can include two condenser plates, between which the mold is arranged and by means of which an electromagnetic field is created in a mold interior.

[0097] However, the electromagnetic waves can also be generated using a microwave generator or magnetron located outside the mold.

[0098] Within the drying station, there is preferably a shielded area where the electromagnetic waves can only irradiate the mold and the fiber casting. This primarily protects bystanders.

[0099] The drying station may include one or more generators for producing and applying electromagnetic radiation, which are arranged within the drying station to heat and thus dry fiber castings located on the transport device.

[0100] The electromagnetic waves can be generated in the drying station by positioning the drying unit outside the mold. This eliminates the need to fix or connect the mold within the drying station. Simply move the mold into the drying station and align the drying unit accordingly. This minimizes drying time and improves the overall manufacturing process.

[0101] At least one of the mold halves can have an electrically conductive surface to which a signal can be applied to generate an electromagnetic field in a mold interior of the molding tool.

[0102] The mold halves are designed such that at least one of them can act as a capacitor plate. An RF signal can be applied to this mold half via a waveguide. A dielectric layer can be placed between the mold half and the fiber casting to prevent uncontrolled current flow to the fiber casting. The opposite mold half can be connected to a capacitor plate that is grounded. Here, too, a dielectric layer can be placed between the mold half and the fiber casting.

[0103] If the second half of the mold is also electrically conductive, it represents the second capacitor plate, which is connected to ground.

[0104] The drying station can be configured to apply a signal to an electrically conductive surface of the mold tool in order to generate an electromagnetic field in a mold interior of the mold tool.

[0105] The drying station can include a wave generator for generating electromagnetic waves, a waveguide and a capacitor plate with a mold tool receiving area, wherein the electromagnetic waves can be introduced from the wave generator into the capacitor plate via the waveguide.

[0106] According to a first embodiment, this device can be characterized in that the capacitor plate has a first dielectric layer in the mold receiving area, and a mold made of an electrically conductive material (metal) can be arranged in the mold receiving area, such that the capacitor plate forms a first capacitor with a first mold half of the mold, and wherein a second dielectric layer is provided in a contact area between the first mold half and a second mold half, such that the first mold half and the second mold half form a second capacitor.

[0107] According to a second embodiment, this device can be characterized in that the forming tool can be directly received between the capacitor plate and the grounding plate, wherein the forming tool is made of a dielectric material so that the capacitor plate and the grounding plate form a capacitor.

[0108] According to a third embodiment, it can be provided that the capacitor plate has a first dielectric layer in the mold receiving area, and a mold consisting of two mold halves is arranged in the mold receiving area, wherein the first mold half is made of an electrically conductive material, such as metal, and the second mold half is made of a dielectric material, so that the capacitor plate forms a first capacitor with the first mold half of the mold, and the first mold half forms a second capacitor with the grounding plate.

[0109] According to a fourth embodiment, it can be provided that a mold consisting of two mold halves is arranged in the mold receiving area, wherein the first mold half is made of a dielectric material and the second mold half is made of metal, so that the capacitor plate forms a capacitor with the second mold half of the mold.

[0110] In a device for using metal forming tools, it is preferably provided that the transfer plate has a dielectric layer in a tool holding area.

[0111] In a device for using molding tools made of electrically insulating material, such as plastic, it is preferably provided that no dielectric layer is provided on the capacitor plate connected to the waveguide.

[0112] In a device for using forming tools made of electrically conductive and non-electrically conductive materials, it is preferably provided that the forming tools made of electrically conductive material each have a dielectric layer in a tool-holding area in a contact area with the transfer plate. Otherwise, the device corresponds to the design for forming tools made of electrically conductive material.

[0113] Preferably, the device for producing a fiber casting is designed in such a way that one or more of the above-described methods or process steps can be carried out with it.

[0114] Further tasks, features and advantages of the present invention will become apparent from the description of the exemplary embodiment shown in the accompanying drawing. This shows in: Figure 1 a schematic representation of a device according to the invention.

[0115] In the following, a device 1 according to the invention for producing a fiber casting 2 is described in more detail using an exemplary embodiment ( Fig. 1 ).

[0116] The device 1 comprises a pulper 3, a drying station 4, a demolding station 5 and a transport device 6.

[0117] The transport device 6 comprises an upper and a lower conveyor belt assembly 7, 8 and a first and a second lifting device 9, 10 and is configured to transport a mold 11 in the device 1 in a circuit. In this way, the transport device 6 enables one or more mold 11s to be transported in a circuit along a transport direction 12.

[0118] The linear conveyor belt devices 7, 8 are coupled at their respective ends to the lifting devices 9, 10 in such a way that the molding tool 11 is transported from one of the conveyor belt devices 7, 8 to the corresponding lifting device 9, 10 and vice versa.

[0119] The conveyor belt systems 7, 8 can comprise one or more transport sections, each with a conveyor belt guided around two deflection rollers and driven independently of one another. The individual transport sections can have different lengths and move at different speeds. Thus, the dwell time of the individual mold tools 11 on the respective transport sections can be adjusted. For example, a transport section can serve as a buffer by being driven slowly and transporting many mold tools 11 arranged close together on the transport section.

[0120] The upper conveyor belt device 7 moves the forming tool 11 from a starting position 13, which designates a position on the upper conveyor belt device 7 after the first lifting device 9 and before the pulper 3, to the individual work stations.

[0121] The lower conveyor belt device 8 runs in the opposite direction to the upper conveyor belt device 7 in order to transport the molding tool 11 from a second lifting device 10 in reverse direction 14 to the first lifting device 9.

[0122] The lifting devices 9, 10 each comprise a single movable platform 15, 16, which is raised and lowered. However, the lifting devices 9, 10 can also be configured as paternoster lifts with several circulating platforms.

[0123] The movable platforms 15, 16 are designed as passive roller conveyors, so that the mold tools 11 can be easily picked up and dropped off.

[0124] 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 of their ends to lift the molding tool 11 from the lower conveyor belt device 8 to the upper conveyor belt device 7 for the start of the manufacturing process of a fiber casting 2.

[0125] 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 of their ends in order to lower the molding tool 11 from the upper conveyor belt device 7 to the lower conveyor belt device 8 after completion of the manufacturing process of a fiber casting 2.

[0126] On the conveyor belt devices 7, 8, a slide 17, 18 is arranged at their end located at the front in the conveying direction or in the transport direction 12 and is designed as a passive roller conveyor, so that the forming tools 11 can slide automatically from the conveyor belt devices 7, 8 onto the corresponding movable platforms 15, 16 of the lifting devices 9, 10.

[0127] A first pusher 19 is arranged on the first lifting device 9 at the level of the upper conveyor belt device 7 in order to push the forming tool 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.

[0128] A second slide 20 is arranged on the second lifting device 10 at the level of the lower conveyor belt device 8 in order to push the forming tool 11 from the platform 16 of the second lifting device 10 onto the lower conveyor belt device 8.

[0129] The mold 11 consists of a lower mold half 21 and an upper mold half 22. Furthermore, the mold 11 is made of a material transparent to electromagnetic waves in order to transmit electromagnetic waves to the fiber casting 2 with minimal 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 and 22 is as thin as possible so that only a small portion of the electromagnetic waves is absorbed.

[0130] The mold halves 21, 22 each comprise an outer and inner surface, the inner surfaces defining a mold interior when the mold tool 11 is closed, which is complementary to the respective shape of the fiber casting 2 to be produced.

[0131] The lower half of the mold 21 is formed from a grid with a multitude of openings or a porous material, so that water can escape downwards.

[0132] The mold halves 21, 22 are held together in the closed state by friction or positive locking. The mold halves 21, 22 can additionally and / or alternatively be connected to each other by friction and / or positive locking using a locking device such as a locking latch or a snap-fit ​​mechanism.

[0133] In the present embodiment, no locking means is provided, since the mold halves 21, 22 are held together by adhesion after forming.

[0134] The mold halves 21, 22 have fitting elements at their 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 matching recesses. When the upper mold half 22 is placed onto the lower mold half 21 with a slight offset, the wedges ensure that the mold halves 21, 22 assume the desired position relative to each other. In this process, the wedges of one mold half 21, 22 slide into the corresponding recesses of the other mold half 22, 21.

[0135] Additional fitting elements include pins and corresponding bores, with one of the mold halves 21, 22 providing the pins and the other mold half 22, 21 providing the matching bores. When the mold halves 21, 22 are joined, the pins engage in the designated bores and consequently prevent horizontal displacement of the mold halves 21, 22 relative to each other.

[0136] The pins are designed to be so long that they only come into contact with the corresponding bores after the wedges have slid into the recesses provided for this purpose and have ensured the correct alignment of the mold halves 21, 22 to each other.

[0137] The mold halves 21, 22 have at least one integrated hollow rail on their outer surface for a sliding closure, the hollow rail of the lower mold half 21 being parallel to the hollow rail of the upper mold half 22. The hollow rails are designed to be as flat as possible, matching the wall thickness of the mold halves 21, 22. The hollow rails are open on one side and are designed to allow the mold halves 21, 22 to slide horizontally into a corresponding mating profile. The hollow rails can be designed, for example, as T-slots or dovetail grooves.

[0138] The pulper 3, the drying station 4, and the demolding station 5 each comprise a device that includes 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 locking element. The open side of the profile rails faces the upper conveyor unit 7, so that the mold halves 21, 22 can be pushed onto the profile rails by the upper conveyor unit 7 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 mating profile can, for example, be designed as a T-profile or as a fitting connector.

[0139] The mold halves 21, 22 have chamfered corners that serve as guide surfaces when the mold halves 21, 22 are moved. Each workstation includes a device that provides corresponding counter-guide surfaces for the guide surfaces of the mold halves 21, 22. The counter-guide surfaces taper conically from the upper conveyor belt device 7 towards the workstation. They are designed to 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 when moved towards the workstation. The counter-guide surfaces converge on the corresponding working position at the workstations, ensuring precise positioning of the mold halves 21, 22 at these positions.

[0140] A first transport section of the upper conveyor belt assembly 7 extends in the transport direction 12 from the first lifting device 9 to a height just before the pulper 3. Subsequently, and with minimal distance to the first transport section, a second transport section follows, allowing for the automatic transfer of a forming tool 11. The second transport section runs parallel to the pulper 3 in such a way that it can supply the pulper 3 with a forming tool 11 and retrieve it from there. The second transport section comprises a conveyor belt with a grid-like design featuring numerous openings, allowing water to drip into a basin below.

[0141] The pulper 3 comprises an upwardly open container 25 and is arranged adjacent to the transport device 6 such that the upper edge of the container 25 is located approximately at the level of the upper conveyor belt device 7.

[0142] A shredding device (not shown) may be provided, designed to break up or shred fibrous material so that the fibrous material is present in thin fiber strands. If the input material is already in thin fiber strands, the shredding device can be omitted and the fibrous material fed directly to pulper 3.

[0143] 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 suspension. This fibrous suspension is a viscous slurry that can be pumped from Pulper 3 into container 23 by means of a pump (not shown).

[0144] The pulper 3 comprises a lower lifting device 24 and an upper lifting device 25, which are vertically movable. The lower lifting device 24 is integrated into the container 23 of the pulper 3. In the present embodiment, the lifting devices 24 and 25 are each a piston / cylinder unit.

[0145] The lifting devices 24, 25 comprise at least one projecting profile rail, preferably with a locking means, to receive the corresponding mold half 21, 22, comprising at least one integrated hollow rail.

[0146] The lower lifting device 24 comprises counter-guide surfaces for the guide surfaces of the lower mold half 21. The counter-guide surfaces extend conically from the upper conveyor belt device 7 towards the lower lifting device 24. They are designed such 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 towards the lower lifting device 24. The counter-guide surfaces converge on the corresponding working position on the lower lifting device 24, thereby ensuring precise positioning of the mold tool 11 at the working position.

[0147] A third slide 27 is arranged opposite the pulper 3 on the other side of the upper conveyor device 7 to push the forming tool 11 onto the lower lifting device 24 of the pulper 3, with the upper half 22 of the forming tool 11 being simultaneously received by the upper lifting device 25.

[0148] A fourth slide 28 is arranged opposite the first slide 27 on the other side of the pulper 3 to push the forming tool 11 back from the lower lifting device 24 of the pulper 3 to the upper conveyor device 7 after completion of the forming process.

[0149] 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 to a height just before the drying station 4.

[0150] In the second transport section, a draining device (not shown) is provided between the pulper 3 and the drying station 4 for the simultaneous draining of one or more fiber castings 2. The draining device is formed either by a section of the transport system 12, in particular the second transport section, or by a separate buffer area (not shown) decoupled from the transport system 12.

[0151] The second transport section is followed by a third transport section, during which 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 supply the mold 11 to the drying station 4 and pick it up again from there.

[0152] The drying station 4 is arranged adjacent to the transport device 6 in such a way that a support plate 31 is arranged approximately at the level of the upper conveyor belt device 7, on which the molding tool 11 rests during the drying process.

[0153] The drying station 4 has a drying device comprising a horizontally arranged capacitor plate 29 and a horizontally arranged grounding plate 30. The capacitor plate 29 is connected to an RF generator 34, which can apply an RF signal to the capacitor plate 29 via a waveguide 35. The grounding plate 30 is connected to ground via a grounding cable 36. The capacitor plates 29 and 30 are designed to generate an electromagnetic field in the area between them, which can be used to apply electromagnetic waves to the fiber casting 2 in the mold 11, thus drying the fiber casting 2.

[0154] In this design, it is possible to make the grounding plate 30 vertically movable, since only one movable grounding cable 36 is led to the plate 30.

[0155] The capacitor plate 29 is fixed in position, which means that the waveguide 35 can also be fixed in position. A reverse arrangement with a movable waveguide is also possible in principle, but technically more difficult to implement.

[0156] The capacitor plate 29 comprises the support plate 31, which rests on the capacitor plate 29 and is firmly connected to it. The grounding plate 30 comprises the plate 32, which is firmly connected to it. The plates 31 and 32 are made of a non-electrically conductive material.

[0157] The grounding rod 30 is connected to a first lifting device 33. In the present embodiment, the first lifting device 33 is a piston / cylinder unit.

[0158] The plates 31, 32 comprise at least one projecting profile rail, preferably with a locking element, for receiving 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 not only serve to fix the mold tool 11 in the drying station, but also 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.

[0159] The support plate 31 of the condenser plate 29 includes counter-guide surfaces for the guide surfaces of the lower mold half 21. The counter-guide surfaces extend conically from the upper conveyor belt assembly 7 towards the support plate 31. They are designed such that they engage with the guide surfaces of the lower mold half 21 as soon as the mold halves 21 leave the upper conveyor belt assembly 7 while being pushed towards the support plate 31. The counter-guide surfaces converge on the corresponding working position on the support plate 31, thereby ensuring precise positioning of the mold tool 11 at the working position.

[0160] The radio frequency signal is preferably generated in a frequency range of at least 5, 10, 15, 20, or 25 MHz up to a maximum of 50, 45, 40, 35, or 30 MHz. The actual frequency used depends on which frequency is approved for industrial use. For example, in Germany, the frequency of 27.12 MHz is permitted. The amplitude can range from a few hundred volts to several kilovolts.

[0161] In another embodiment, the drying station 4 includes the wave generator 34 for generating electromagnetic waves, the waveguide 35, the capacitor plate 29 and the grounding plate 30.

[0162] The capacitor plate 29 and the grounding plate 30 are made of metal.

[0163] The electromagnetic waves can be introduced into the capacitor plate 29 via the waveguide 35 using the wave generator 34.

[0164] The grounding plate 30 is connected to ground via a grounding cable 36.

[0165] The capacitor plate 29 and the grounding plate 30 are arranged such that they form a mold-fitting area between them. The mold-fitting area is designed to receive a mold 11 made of an electrically conductive material (metal).

[0166] In this arrangement, the capacitor plate 29 and the first mold half 21 of the molding tool 11 form a first capacitor, and the first mold half and the second mold half 22 of the molding tool 11 form a second capacitor.

[0167] A first dielectric layer 31 is arranged between the capacitor plate 29 and the first mold half 21 of the mold tool 11. The first dielectric layer 31 is preferably fixedly arranged on the capacitor plate 29, but can also be arranged on a surface of the first mold half 21.

[0168] A second dielectric layer is arranged between the first mold half 21 of the mold tool 11 and the second mold half 22 of the mold tool 11. The second dielectric layer is arranged equally in both mold halves 21, 22 or only in one of the two mold halves 21, 22.

[0169] The dielectric layer between the capacitor plate 29 and the first mold half 21 creates a defined plate capacitor that reliably transmits the electromagnetic waves to the fiber casting 2 and does not lead to uncontrolled welding or electrical flashovers between the metallic components of the arrangement.

[0170] It is also possible to couple the waveguide 35 directly to the first mold half 21 of the molding tool 11, and to couple the grounding cable 36 directly to the second mold half 22 of the molding tool 11, however this is technically more difficult to implement.

[0171] The amplitude can also be gradually increased from a small initial value to a larger final value. The increase preferably follows a linear path along a predetermined ramp. The slope and / or the final value of the ramp can be varied depending on the water content in the fiber casting 2.

[0172] In the embodiment described above, electromagnetic waves in the form of RF radiation are used. Microwave radiation could also be used instead of RF radiation. Microwave radiation can be generated very easily and cost-effectively using a magnetron. When using microwave radiation, the capacitor is not required. Such a device operating with microwave radiation is simpler and less expensive than one operating with RF radiation, but it has significant disadvantages due to the short wavelength and the inhomogeneous radiation distribution. The short wavelength of microwave radiation results in considerable local variations in heat input. This can lead to undesirable uneven heating, particularly in larger fiber castings.

[0173] When using microwave radiation instead of RF radiation, the plate capacitor in the above-described embodiment can be replaced by a microwave tunnel to which microwaves are supplied by means of one or more magnetrons.

[0174] A fifth slide 37 is arranged opposite the drying station 4 on the other side of the upper conveyor device 7 to push the molding tool 11 onto the support plate 31 of the lower condenser plate 29, with the upper mold half 22 of the molding tool 11 being simultaneously received by the plate 32 of the upper condenser plate 30.

[0175] A sixth slide 38 is arranged opposite the slide 37 on the other side of the drying station 4 to push the molding tool 11 from the support plate 31 of the lower condenser plate 29 back onto the upper conveyor device 7 after completion of the drying process.

[0176] The third transport section of the upper conveyor belt system 7 extends in the transport direction 12 from the position parallel to the drying station 4 to the first chute 17 after the demolding station 5. The third transport section runs parallel to the demolding station 5 in such a way that it can supply the mold 11 to the demolding station 5 and pick it up again from there. In addition, a cooling station (not shown), which is located upstream of the demolding station 5, can be provided along the third transport section to rapidly cool the mold 11 and the fiber casting 2. The mold 11 and the fiber casting 2 were heated intensely using electromagnetic waves.

[0177] A cooling station is an optional workstation. If active cooling is planned, the cooling station makes the entire process more efficient.

[0178] The cooling station includes a cooling device, which is at least an air blower, to quickly cool the mold 11 and the fiber casting 2.

[0179] The cooling station is preferably a long tunnel along the third transport section of the upper conveyor system 7, which begins shortly after the drying station 4 and ends shortly before the demolding station 5 and includes several air blowers to gradually cool the mold tool 11 and the fiber casting 2 as they pass through the tunnel.

[0180] After the cooling station, the demolding station 5 follows to open the mold 11 and remove the fiber casting 2.

[0181] 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 molding tool 11 rests during the demolding process.

[0182] The demolding station 5 comprises a second lifting device 40, which is vertically movable and in the present embodiment is a piston / cylinder unit.

[0183] 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 are thus movable in the vertical direction.

[0184] The gripping device 42 comprises a gripper 43 which is designed to grip the finished fiber casting 2 from the opened mold tool 11.

[0185] The second lifting device 40 and the gripping device 42 are each attached to a rail 45 by means of a slide 44, 50 and are thus horizontally movable.

[0186] The demolding surface 39 and the second lifting device 40 comprise at least one projecting profile rail, preferably with a locking means, to receive the corresponding mold half 21, 22, comprising at least one integrated hollow rail.

[0187] The demolding surface 39 includes counter-guide surfaces for the guide surfaces of the lower mold half 21. The counter-guide surfaces extend conically from the upper conveyor belt 7 towards the demolding surface 39. They are designed such 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 7 while being pushed towards the demolding surface 39. The counter-guide surfaces converge on the corresponding working position on the demolding surface 39, thereby ensuring precise positioning of the mold tool 11 at the working position.

[0188] 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 molding tool 11 onto the demolding surface 39 of the demolding station 5, with the upper mold half 22 of the molding tool 11 being simultaneously picked up by the second lifting device 40.

[0189] An eighth slide 47 is arranged opposite the slide 46 on the other side of the demolding station 5 to push the molding tool 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.

[0190] Preferably a cleaning station 48 is provided and designed along the lower conveyor belt device 8 to clean the molding tool 11 before reuse.

[0191] The cleaning station 48 includes a cleaning device 49, which may be a water shower that rinses the molding tool 11.

[0192] The following describes a method for producing a fiber casting 2 using the device 1 described above. The method is described below using the example of a single mold. However, it is intended that the method can be used to process several molds sequentially and / or in parallel at the workstations.

[0193] The forming tool 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.

[0194] The upper conveyor belt device 7 transports the forming tool 11 to the height of the pulper 3.

[0195] The forming tool 11 is pushed onto the lower lifting device 24 of the pulper 3 by means of the third slide 27. The upper half 22 of the forming tool 11 is simultaneously picked up by the upper lifting device 25.

[0196] The integrated profile rails of the lower mold half 21 and the upper mold half 22 engage in the corresponding counter-profiles, preferably with a locking means, of the lower lifting device 24 and the upper lifting device 25, and fix the mold halves 21, 22.

[0197] 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 fiber suspension 26, i.e., that the lower mold half 21 is then completely immersed in the fiber suspension and fills with fiber suspension. Figure 1 The lower lifting device 24 is designed such that it extends through the bottom of the container 23. In practice, however, it is often simpler to arrange the lower lifting device 24 completely inside the container 23, as then no opening needs to be sealed.

[0198] The upper and lower mold halves 22, 21 are brought together in such a way that they define an interior space between them which corresponds approximately to the fiber casting part 2 to be produced.

[0199] The two mold halves 21, 22 can be brought together in the pulper 3 below the level of the fiber suspension, so that the entire mold interior is filled with the fiber suspension. Then the mold tool 11 is raised above the level to approximately the height of the upper conveyor belt 7.

[0200] After raising the mold 11 with the fiber suspension above the level of the container 23 of the pulper 3, the moisture content of the fiber casting 2 is quickly reduced to a value of a maximum of 80 wt.% or a maximum of 70 wt.% or a maximum of 60 wt.%.

[0201] The two lifting devices 24, 25 press the two mold halves 21, 22 together in such a way that water is forced out of the fiber suspension located in the mold interior of the mold tool 11 and the fiber suspension is formed into the fiber casting 2.

[0202] After the fiber casting 2 has been formed, the molding tool 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.

[0203] During the forming process, when the wet fiber suspension is compressed in the mold 11, the outlet holes of the mold 11 become blocked and the joints are sealed. This prevents air from entering the mold 11. As a result, the mold halves 21 and 22 adhere to each other, requiring considerable force to separate them. This bond can be so strong that no locking mechanism is necessary to prevent accidental separation of the mold halves 21 and 22. In this case, it is unnecessary to use the locking or detent device on the mold 11.

[0204] The upper conveyor belt 7 transports the mold 11 from the pulper 3 to the draining unit. In the draining unit, the mold 11 drains until the fiber casting 2 has reached a predetermined moisture content and is suitable for drying by means of electromagnetic waves in the drying station 4.

[0205] Here, it is possible to mold and / or dry several fiber castings 2 in immediate succession, whereby several molds 11 containing the fiber castings 2 can be held for draining in one step until sufficient moisture has escaped from the molds 11. As soon as a predetermined degree of dryness is reached, a mold 11 with a fiber casting 2 can then be transferred to the drying station 4.

[0206] After pressing the fiber suspension in the mold 11 and draining, the fiber casting 2 still has a moisture content of a maximum of 30 wt.% or a maximum of 25 wt.% or a maximum of 20 wt.%.

[0207] From the draining device, the conveyor belt device 7 transports the molding tool to the drying station 4, which has a drying device.

[0208] The forming tool 11 is pushed onto the storage surface 31 of the drying device by means of the fifth slide 37.

[0209] The grounding 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 condenser plate 29 via the support surface 31.

[0210] The capacitor plate 29 and the grounding plate 30 are designed to generate a strong alternating electromagnetic field between themselves 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 fiber casting 2.

[0211] The RF waves are largely absorbed by the water contained in the fiber casting 2. The water is heated and evaporates from the fiber casting 2, causing it to dry and harden.

[0212] The use of RF waves makes it possible to quickly heat the fiber casting 2 from the inside out in a short time, thus achieving the desired degree of drying correspondingly quickly. Alternatively, the mold 11 could be heated directly via a heating device, thereby indirectly drying the fiber casting 2. However, this is considerably slower than direct heating of the fiber casting 2 using electromagnetic waves.

[0213] In addition to RF waves, microwaves can also be used as electromagnetic waves. However, RF waves have the advantage over microwaves that, due to their longer wavelength, they heat the entire fiber casting 2 evenly at once. With microwaves, the heat input is locally limited, and they are therefore more suitable for smaller fiber castings 2.

[0214] By drying the fiber casting 2 using electromagnetic waves, the moisture content of the fiber casting 2 is reduced to a value of a maximum of 10 wt.% or a maximum of 7.5 wt.% or a maximum of 5 wt.%.

[0215] In a further embodiment, a method for drying the fiber casting 2 in the drying station 4 is provided, in which a mold 11, which is made of an electrically conductive material (metal) and 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 grounding plate 30.

[0216] Electromagnetic waves are generated by the wave generator 34 and introduced into the capacitor plate 29 via the waveguide 35. The grounding plate 30 is connected to ground via a grounding cable 36.

[0217] The first mold half 21 of the mold tool 11 is in contact with 31 of the capacitor plate 29 via a first dielectric layer. The first mold half 21 and the capacitor plate 29 form a first capacitor.

[0218] The first mold half 21 of the mold tool 11 and the second mold half 21 form a second capacitor.

[0219] The electromagnetic waves are transmitted via the capacitor plate 29 and the first mold half 21 of the mold tool 11 to the fiber casting 2 and dry the fiber casting 2.

[0220] After the drying process, the grounding plate 30 of the drying device is moved upwards away from the upper half 22 of the molding tool 11 by means of the first lifting device 33.

[0221] The forming tool 11 is pushed from the storage area 31 of the drying device back onto the upper conveyor belt device 7 by means of the sixth slide 38.

[0222] The upper conveyor belt 7 transports the mold 11 from the drying station 4 to the cooling station. The cooling station is an optional workstation. If active cooling is planned, a cooling station makes the entire process more efficient.

[0223] The cooling station is arranged so that the mold 11 with the fiber casting 2 can remain on the upper conveyor belt device 7 and be cooled there.

[0224] The mold 11 with the fiber casting 2 is cooled by one or more air blowers of the cooling station as it passes through the cooling station.

[0225] The mold 11 is simultaneously transported to the demolding station 5 during the cooling process. The upper conveyor belt 7 transports the mold 11 to the level of the demolding surface 39.

[0226] The mold 11 is pushed onto the demolding surface 39 of the demolding station 5 by means of the seventh slide 46. The upper mold half 22 of the mold 11 is simultaneously picked up by the second lifting device 40.

[0227] The integrated profile rails of the lower mold half 21 and the upper mold half 22 engage in the corresponding counter-profiles, preferably with a locking means, the demolding surface 39 and the lifting device 40, and fix the mold halves 21, 22.

[0228] By lifting the upper half of the mold 22 using the second lifting device 40, the mold tool 11 is opened and the fiber casting 2 is exposed.

[0229] The second lifting device 40 and the gripping device 42 are moved by means of the slides 44, 50 in the rail 45 such that the second lifting device 40 moves to the side with the upper mold half 22 and the gripping device 42 comes to a stop above the fiber casting part 2 and the lower mold half 21.

[0230] The fiber casting 2 can be picked up by lowering the gripping device 42 using the third lifting device 41 and closing the gripper 43. The fiber casting 2 can then be placed on the support surface 51 by raising and lowering the gripping device 42 accordingly and moving the carriage 44 in the rail 45.

[0231] The upper mold half 22 can be synchronously rejoined with the lower mold half 21 by raising and lowering the second lifting device 40 accordingly and by moving the carriage 50 in the rail 45.

[0232] After the demolding process, the molding tool 11 is pushed back from the demolding surface 39 of the demolding station 5 onto the upper conveyor belt device 7 by means of the eighth slide 47.

[0233] The upper conveyor belt device 7 transports the molding tool 11 further from the demolding station 5 to the first slide 17.

[0234] The forming tool 11 is conveyed from the upper conveyor belt device 7 onto the first slide 17 and from there automatically moved by means of the passive roller conveyor of the slide 17 onto the second movable platform 16 of the second lifting device 10.

[0235] The second lifting device 10 transports the forming tool 11 downwards to the level of the lower conveyor belt device 8, where the forming tool 11 is pushed by means of the second slide 20 from the movable platform 16 onto the lower conveyor belt device 8 and simultaneously in the direction of cleaning station 48.

[0236] The cleaning device 49, which can be a water shower, cleans the mold tool 11 as it travels through the cleaning station 48 on the lower conveyor belt device 8.

[0237] After cleaning is complete, the molding tool 11 is transported by the lower conveyor belt 8 to the second chute 18 and from the lower conveyor belt 8 onto the second chute 18. From there, the molding tool 11 is automatically moved by means of the passive roller conveyor of the second chute 18 onto the movable platform 15 of the first lifting device 9.

[0238] The first lifting device 9 transports the molding tool 11 upwards to the level of the upper conveyor belt device 7, where it is then ready for the next molding process.

[0239] In the embodiment described above, the mold 11 is lowered into the container 23 and closed there to receive the fiber suspension in the mold cavity. It is also possible to position the lower mold half 21 stationary above the container 23 and pump the fiber suspension from below through the lower mold half 21 into the mold cavity defined by the mold 11. Water can then escape from the mold cavity through the lower mold half 21 and drip back into the container 23.

[0240] To avoid excessive dilution of the fiber suspension in the container 23 in the long term, it may also be useful to drain the water escaping from the molding tool 11 so that it does not enter the container 23.

[0241] In the embodiment described above, the capacitor plate 29 and the grounding plate 30 are designed such that the capacitor plate 29 is in contact with the lower mold half 21 and the grounding plate 30 is press-fitted onto the upper mold half 22. Alternatively, the two capacitor plates 29, 30 can also be positioned laterally against the two mold halves 21, 22.

[0242] In the embodiment described above, the cycle rate of the cooling station primarily determines how many fiber castings 2 are produced per unit of time and thus the efficiency of the entire process. Cooling the fiber castings 2 is the most time-consuming step. Molding, drying, and demolding the fiber castings 2, on the other hand, are faster.

[0243] Pulper 3 can be equipped with a recirculating device that operates independently of the upper conveyor belt 7 and is designed to accommodate several molds 11 after the fiber casting 2 has been formed. This allows further fiber castings 2 to be formed while others are still in the drying station 4. The recirculating device can be an additional conveyor belt that moves the molds 11 in a cycle. The speed of this conveyor belt can be adjusted variably and independently of the upper conveyor belt 7 and the transport device 6.

[0244] The additional conveyor belt can be designed as a grid, allowing water to drip through into a collection container. The circulation device can also be a paternoster 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.

[0245] The cooling station can be designed as a circulating device that operates independently of the upper conveyor belt 7 and is configured to hold several molds 11 after the fiber casting 2 has dried, in order to cool the fiber castings 2 in the air. Furthermore, additional fiber castings 2 can be dried in this way while others are still in the cooling station. The circulating device can be another conveyor belt that moves the molds 11 in a cycle. The speed of this conveyor belt can be variably adjusted independently of the upper conveyor belt 7 of the transport device 6. The circulating device can also be a paternoster lift that moves the molds 11 in a circle. A possible and inexpensive alternative to the circulating device is a long conveyor belt section between the drying station and the demolding station 5.The cooling station can be a tunnel containing several air blowers that dry the mold tools 11 as they pass through. This allows the upper conveyor belt system 7 to continue running continuously. Reference symbol list

[0246] 1 Device 2 Fiber casting 3 Pulper 4 Drying station 5 Demolding station 6 Conveyor device 7 Upper conveyor device 8 Lower conveyor device 9 First lifting device 10 Second lifting device 11 Molding tool 12 Conveyor direction 13 Starting position 14 Reverse direction 15 First moving platform 16 Second moving platform 17 First chute 18 Second chute 19 First slide 20 Second slide 21 Lower mold half / First mold half 22 Upper mold half / Second mold half 23 Container 24 Lower lifting device 25 Upper lifting device 26 Fiber suspension mirror 27 Third slide 28 Fourth slide 29 Capacitor plate 30 Grounding plate 31 Settling plate / First dielectric layer 32 Plate 33 First lifting device 34 RF generator 35 Waveguide 36 Grounding cable 37 Fifth slide 38 Sixth slide 39 Demolding surface 40 Second lifting device 41 Third lifting device 42 Gripping device 43 Gripper 44 First carriage 45 Rail 46 Seventh slide 47 Eighth slide 48 Cleaning station49 Cleaning device 50 Second carriage 51 Storage area

Claims

1. A method for producing a fiber molding (2), comprising the steps of - dissolving fiber materials in water to form a fiber material suspension in a pulper (3), - dehumidifying the fiber material suspension by pressing it into a fiber molding (2) in a forming tool (11) and / or - drying the fiber molding (2) by supplying heat within the forming tool (11) and - demolding the fiber molding (2) from the forming tool (11), wherein, during a form drying process of the fiber molding (2), the fiber molding (2) is exposed to electromagnetic waves such that it dries in the forming tool (11) until a moisture content of the fiber molding (2) of at most 10 wt.-%, at most 7.5 wt.-%, or at most 5 wt.-% is reached, characterized in that the fiber molding (2) is dried in a drying station (4) and demolded from the forming tool (11) in a demolding station (5), wherein the pulper (3), the drying station (4), and the demolding station (5) form processing stations.

2. The method according to claim 1, characterized in that the fiber molding (2) has a moisture content of a maximum of 30 wt.-%, a maximum of 25 wt.-%, or a maximum of 20 wt.-%, respectively, after the fiber material suspension has been dehumidified in the forming tool (11).

3. The method according to claim 1 or 2, characterized in that the forming tool (11) is transported by a transport device (6) from the pulper (3) to the drying station (4) and to the demolding station (5), and / or one or more forming tools (11) are transported in at least one loop by means of the transport device (6).

4. The method according to any one of claims 1 to 3, characterized in that one or more forming tools (11) are releasably attached to at least one of the workstations and / or to the transport device (6), such that after processing in at least one of the workstations, one or more forming tools (11) are, preferably automatically, coupled into or uncoupled from one of the workstations and / or the transport device (6) accordingly, and / or a step of draining the fiber molding (2) in the forming tool (11) is provided between the dehumidification step and the drying step.

5. The method according to any one of claims 1 to 4, characterized in that the drying station (4) and / or a cooling station and / or the demolding station (5) are arranged in a transport direction (12) along the transport device (6) and can each accommodate at least one forming tool (11) for processing, either sequentially and / or simultaneously, and / or the drying station (4) and / or the cooling station and / or the demolding station (5) are arranged in the transport direction (12) along the transport device (6), wherein in each case several work stations, in particular drying stations (4), are provided to be able to accommodate two or more forming tools (11) for processing, either sequentially and / or simultaneously.

6. The method according to any one of claims 1 to 5, characterized in that the forming tool (11) is arranged between at least two capacitor plates (29, 30) of the drying station (4), the electromagnetic waves being applied to the forming tool (1) via the capacitor plates (29, 30), and / or in the drying station (4), electromagnetic waves are generated by a wave generator (34) and introduced via a waveguide (35) into a capacitor plate (29) having a forming tool receiving area.

7. The method according to claim 6, characterized in that the capacitor plate (29) comprises a first dielectric layer (31) in the forming tool receiving area, and a forming tool (11) made of an electrically conductive material is arranged in the forming tool receiving area, so that the capacitor plate (29) forms a first capacitor with a first mold half (21) of the forming tool (11), and a second dielectric layer is provided in a contact region between the first mold half (21) and a second mold half (22), so that the first mold half (21) and the second mold half (22) form a second capacitor, and / or the forming tool (11) is directly received between the capacitor plate (29) and a ground plate (30), the forming tool (11) being made of a dielectric material, so that the capacitor plate (29) and the ground plate (30) form a capacitor.

8. The method according to any one of claims 1 to 7, characterized in that simultaneously with the application of the electromagnetic waves, the fiber molding (2) is compressed in the forming tool (11) in the drying station (4).

9. An apparatus (1) for producing a fiber molding (2), comprising - a pulper (3) for dissolving fiber materials in water to form a fiber material suspension, - a forming tool (11) having two mold halves (21, 22) for dehumidifying the fiber material suspension by pressing it into a fiber molding (2), - a drying station (4) for drying the fiber molding (2) by supplying heat within the forming tool (11) and - a demolding station (5) for demolding the fiber molding (2) from the forming tool (11), wherein the drying station (4) comprises a wave generator (34) for electromagnetic waves and a control device, which are configured such that the fiber molding (2) is dried by means of the electromagnetic waves to a moisture content of at most 10 wt.-%, at most 7.5 wt.-%, or at most 5 wt.-%, characterized in that a transport device (6) is provided, by means of which the forming tool (11) can be conveyed from the pulper (3) to the drying station (4) and to the demolding station (5), wherein the pulper (3), the drying station (4), and the demolding station (5) form processing stations.

10. The apparatus (1) according to claim 9, characterized in that the forming tool (11) comprises a temperature sensor and / or a humidity sensor, wherein the control device for controlling the wave generator (34) is configured such that, depending on the measured temperature and / or the measured humidity, energy is supplied to the forming tool (11) by means of the electromagnetic waves, and / or one or more forming tools (11) are provided, which can be detachably secured to the work stations and / or to the transport device (6).

11. The apparatus (1) according to claim 9 or 10, characterized in that the mold halves (21, 22) and / or the transport device (6) and / or the workstations comprise connecting means for coupling and uncoupling the mold halves (21, 22), and / or coupling / decoupling means are provided to couple and decouple the forming tools (11) into / from the transport device (6) and / or the workstations.

12. The apparatus (1) according to any one of claims 9 to 11, characterized in that a drainage device for draining one or more fiber moldings (2) is provided between the pulper (3) and the drying station (4), said draining device being formed either by an area of the transport device (6) or by a separate buffer area decoupled from the transport device (6), and / or the drying station (4) comprises two capacitor plates (29, 30), between which the forming tool (11) can be arranged in a forming tool receiving area, and the electromagnetic waves being able to be applied to the forming tool (11) by means of the capacitor plates (29, 30).

13. The apparatus (1) according to any one of claims 9 to 12, characterized in that the drying station (4) comprises a wave generator (34) for generating electromagnetic waves, a waveguide (35), and a capacitor plate (29) having a forming tool receiving area, the electromagnetic waves being able to be introduced from the wave generator (34) via the waveguide (35) into the capacitor plate (29).

14. The apparatus (1) according to claim 13, characterized in that the capacitor plate (29) comprises a first dielectric layer (31) in the forming tool receiving area, and a forming tool (11) made of an electrically conductive material can be arranged in the forming tool receiving area, so that the capacitor plate (29) forms a first capacitor with a first mold half (21) of the forming tool (11), a second dielectric layer being provided in a contact area between the first mold half (21) and a second mold half (22), so that the first mold half (21) and the second mold half (22) form a second capacitor, and / or the forming tool (11) can be directly received between the capacitor plate (29) and a ground plate (30), the forming tool (11) being made of a dielectric material, so that the capacitor plate (29) and the ground plate (30) form a capacitor.

15. The apparatus (1) according to any one of claims 9 to 14, characterized in that the device (1) is configured to perform a method according to any one of claims 1 to 8.

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