Apparatus for forming a molded fiber product

Abstract

The invention relates to an apparatus for forming a molded fiber product. The apparatus comprises a foam generator (23) for forming foam from fibers, water, air and foaming chemicals. The apparatus further comprises: a mold pair (11) of molds (12, 13) with a variable distance; and a device (24) for supplying foam between the molds (12, 13) to form a layer (10). As part of the device (24), one of the molds (12, 13) has a plurality of transverse channels (19) arranged to open between the molds (12, 13), and the mold pair (11) is sealed from its sides.

Description

Technical Field

[0001] The present invention relates to an apparatus for forming a molded fiber product, the apparatus comprising: a foam generator for forming foam from fibers, water, air and foaming chemicals; a pair of molds with a variable distance; and a device for supplying foam between the molds to form a layer. Background Art

[0002] European Patent No. 1373620B1 discloses an apparatus for producing a three-dimensional fiber web product. The apparatus utilizes a device for generating foam from at least water, air and fibers. The foam is then fed into a mold, and the water and air are removed by pressing. After the product is formed, the product is dried by heating.

[0003] In the known technology, the foam is deposited into a deep basin-shaped mold with a headbox. Due to the independent forming and pressing sequences, the forming and water removal speeds are slow and the foam may be unevenly spread to the mold. This equipment is mainly suitable for corrugated products with larger volumes (such as filters or insulators). Summary of the invention

[0004] The object of the present invention is to provide a new apparatus for forming moulded fibre products which is more versatile and faster than previous apparatuses. The present invention provides an apparatus for forming moulded fibre products, said apparatus comprising: a foam generator for forming foam from fibres, water, air and foaming chemicals; a mould pair with moulds at a variable distance; and means for feeding foam between said moulds to form a layer, wherein, as part of said means, one of said moulds has several transverse channels arranged to be open between said moulds and said mould pair is sealed from its sides. The apparatus itself comprises a number of options to adjust the operation and the product. The operation is improved by using a plurality of forming and foaming units for rapid batch operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The present invention is described in detail below with reference to the accompanying drawings, which show some embodiments of the present invention, in which:

[0006] Figure 1a A top view showing a former of the apparatus according to the invention,

[0007] Figure 1b Shows Figure 1a Side view of

[0008] Figure 2a A top view showing the drainage system of the former of the apparatus according to the invention,

[0009] Figure 2b Shows Figure 2a Side view of

[0010] Figure 3a shows a top view of a mold according to the present invention,

[0011] Figure 3b Shows Figure 3a A side view of a mold and a molded fiber product,

[0012] Figure 4a shows a side view of a pair of dies according to the present invention,

[0013] Figure 4b Shows Figure 4a A partial enlarged view of . DETAILED DESCRIPTION

[0014] Figure 1a-Figure 2b The start of a production line using the apparatus according to the invention is shown. The apparatus is used to form a moulded fibre product. In the apparatus, a layer 10 is formed of foam ( Figure 3b ). This layer is part of the final product and it is further processed in the production line. The foam comprises fibers, water, air and one or more foaming chemicals. For example, it may also have fillers and other conventional papermaking chemicals (such as additives, pigments, dyes and adhesives). The fibers may include all types of fibers from chemical and mechanical pulping, recycled fibers, broken paper, by-products, micro- or nano-fibrillated cellulose and regenerated fibers and combinations of the above. The recipe of a single foam layer may consist of a freely selected mixture of the above-mentioned raw materials. Of course, the recipes of different layers may differ from each other. The layer is formed by the mold pair 11 of molds 12 and 13. In practice, these forming molds consist of several partial molds or of sub-molds in a partial mold, each partial mold is used for one product, and the sub-molds are used for several individual small products (such as cups). In Figure 3a In the embodiment of the present invention, 24 partial molds 14 are combined together as a mold. In principle, one mold is a negative mold and the other mold is a corresponding positive mold. In this way, a three-dimensional shape is obtained during the shaping of the layer. Water and air must be removed from the foam. This is mainly achieved by closing the mold pair. In other words, the distance between the molds changes. When the mold pair is closed, the pressure forces air and water to leave the foam supplied between the molds 12 and 13. The porous product surface of the mold provides a channel for water and air to leave, while the remaining fibers form a layer. After opening the mold pair, the layer can be moved to the next processing stage. The foam is made by one or more foam generators. The foam generator also acts as a foam tank to hold and provide foam for supplying the foam to the shaping section.

[0015] According to the present invention, foam is supplied via one of the molds 12 or 13, while the mold pair 11 is sealed from its side. Therefore, even if the mold is separated (i.e., the mold pair is opened), there is still a closed cavity for foam. In this way, the supply of foam is faster and the choice of time is freer than before. The non-product surface of the mold is used for the entrance of the foam. Specifically, the through opening is located at the selected edge of the partial mold, especially between the relative surfaces of the adjacent partial molds. Foam can be supplied via two molds. However, in the embodiment shown, the mold pair 11 is composed of an upper mold 13 and a lower mold 12, and the upper mold 13 is moved while the lower mold 12 is set to be fixed. In other words, the lower mold 12 is fixed, and foam is supplied via the lower mold. The upper mold is movable. In this way, the pipes and other conduits connected to the lower mold are also kept in place, and the movable upper mold can be lightweight. The light upper mold can be moved quickly and accurately. This accelerates the forming stage. At the same time, the pipes and other conduits remain fixed.

[0016] Since the mold pair is sealed, the foam can be supplied while the mold pair 11 is in the open state, opening and / or closing. This shortens the molding cycle. Figure 1b In the embodiment, even if the upper mold 13 has just risen, the foam will be supplied to the right mold pair 11. On the other hand, the mold pair can be opened first and then the foam is supplied. The structure and function of the device will be described in more detail later.

[0017] Feeding through the die offers yet another advantage. Now, in addition to one layer, multiple layers can also be formed layer by layer. After forming, the formed layer can be removed from the die pair. However, according to the invention, after closing the die pair 11 (i.e. after the layer has been formed), the die pair is opened again and more foam is fed to form a further layer 15, and then the die pair 11 is closed again. Here too, foam can be fed even when the die pair is opening. In practice, 1 to 10 further layers are formed, advantageously 2 to 4 further layers. After forming and pressing, air and unbound water are removed, and the semi-finished product is then transferred to the next processing stage. The next stage is hot pressing to remove water bound to the fibers ( Figure 2b ). After the former, there is a conveyor 16 and then a first hot press 17. Figure 3b 1 shows a product with three layers which are finally bonded together in a hot press. Surprisingly, additional layers 15 can be formed on either side of the fiber product. In other words, when the product is formed with one or more layers, the foam is supplied to either side of the previous layer. For example, an inner layer can be formed first as a bulk layer, and then a layer can be formed on each side of the inner layer as a surface layer. There are then three layers in total.

[0018] The multi-layer product can be realized in another way. According to the invention, the product is composed of multi-layer partial products from two mold pairs 11. In the embodiment shown, there are two parallel mold pairs 11 close to each other. The formed partial products from these two mold pairs can then be combined and hot pressed into one product. For example, an inner layer with a bottom layer is formed in one mold pair. At the same time, an inner layer with a top layer is formed in the other mold pair. When these layers are combined, a product with four layers is formed.

[0019] There are great benefits to forming several layers quickly in one product. However, according to the invention, the foam can be changed before forming another layer. In other words, foams with different properties can be used when forming one product. In this way, the layers can be different from each other. As mentioned above, the product can include, for example, one or two inner layers formed of one foam. Then, there can be at least one outer layer of another foam. Thus, the foam changes in the cross-sectional profile of the product.

[0020] Surprisingly, the fiber product is formed without additional heating. Since the foam has a low water content and contains a lot of air, the water is effectively removed and the product retains its shape after forming. At the same time, the foam retains its shape and the energy consumption is low. More precisely, the temperature of the foam is kept between 15-45 degrees Celsius, advantageously between 25-35 degrees Celsius. If necessary, the foam generator, the foam tank or the mold can be cooled to keep the temperature stable. In addition, at low temperatures, the fibers of the product still have some moisture. Then, during hot pressing, the moisture is carried away in the form of water and steam with heat, which also smoothes the surface and helps internal bonding, thus forming a strong layered product.

[0021] The time that the foam keeps its shape in the pipe flow outside the foam generator is quite short, for example, at most one or two minutes. According to the present invention, the foam is circulated before and after supply. In practice, before supply, the generated foam is directed to the vicinity of the mold. If it is not supplied to the mold, it will circulate back to the foam generation part. Correspondingly, if the foam is introduced into the mold, it will circulate back to the production again until the mold pair is opened. Just when the mold pair is opened, the foam is supplied to the mold space. When the mold pair is closed again, the supply stops and the water is discharged from the mold pair. At the same time, the air is removed. The vacuum can help to remove water and air by pressing. In practice, the discharged water is collected and returned to the foam generation part. Advantageously, the water from different foams has its own tank or compartment in a single tank. The foam can be supplemented with at least one chemical, which circulates back to the foam generation part. In this way, the returned water includes the chemical, which is used when generating more foam.

[0022] Although single-layer products can also be manufactured by the device according to the invention, the device is advantageous when multiple layers are formed. The foam is made of water, air, fibers and foaming chemicals. The foam contains small fractions or small particles of the fibers in question. In addition, the foaming chemicals are used to help the foam to form and keep the foam in shape. The fibers may vary greatly, for example, wood or plant fibers (such as straw, bagasse and bamboo) can be used, but also artificial cellulose fibers can be used. In a suitable foam, water, fibers and possible additives are evenly distributed on the cell walls of the foam. In other words, the foam is a non-flocculated heterogeneous fiber raw material, in which the air of the bubbles brings the fibers and any other raw materials to the forming operation. When using foam, the retention rate of the fibers is also high. In practice, in products formed with thick foam as a carrier medium, more than 99% of the fibers are retained. In addition, depending on the use, the additives can have different retention rates. In practice, the additives can follow the water and circulate in the operation, thereby saving, for example, foaming chemicals.

[0023] For fiber products formed into several layers, the properties of the product can be customized in many ways. For example, the basic structure and surface properties can be formed by different foam compositions. In practice, each layer can have its own treatment. For example, the rigid body of the product can be formed from cheaper fibers, and then the surface layers are formed from materials with higher quality. Compared with the known treatments using aqueous fiber slurries, the fiber density is much higher in the foam. At the same time, the amount of water circulating in the bubble wall is much less, so it is easy to remove water during forming. Foams with less water can achieve fast cycles of operation.

[0024] According to the device, it is now possible to change the foam composition or type for different layers of the product. Preferably, there is another pair of molds in the same foam cycle. In this way, the cycle continues almost without interruption. At the same time, the foam remains dynamic and uniform in the foam cycle. In the cycle, the foam flows at a speed of several meters per second. Nevertheless, the foam is quickly fed into the mold space, especially when a vacuum is used.

[0025] In a proper foam, the gas bubbles do not separate and the fibers are evenly distributed. During forming, the foam is distributed into the mold space between two molds. The volume of the mold space is defined according to, for example, the desired layer thickness.

[0026] With the sealed mold pair, the possibilities for adjusting the forming operation are much greater than before. For example, the next layer can be formed on either side of the previous layer. Furthermore, the feeding can be started while the mold pair is being opened. This is advantageous because during the opening process the mold space is immediately filled with foam without excess air.

[0027] According to the invention, the foam is fed through a mould. Figure 3a A mold 12 with an inlet 18 is shown. More precisely, each inlet is connected to a lateral channel 19 through the mold 12 and also has a return duct 20. In this way, the foam flows constantly through the mold. Advantageously, the lateral channel 19 opens between the products via several openings 21 on the mold surface, more precisely, to the neck area between the product areas of the mold. In this way, the foam will spread quickly and evenly between the molds. Here, the openings are located on the neck area between the products and the openings are upward. At the same time, the opposing mold has a pin 22 at the point of the opening 21. The pin has two main tasks. First, each pin guides the mold during closing. This maintains the shape of the mold pair and the accuracy of the product. Secondly, each pin closes its own opening. Therefore, closing the mold pair automatically cuts off the supply, preventing backflow to the inlet or the lateral channel. Vice versa, opening the mold pair opens the lateral channel and the foam fills the mold space.

[0028] A vacuum can also be used. The vacuum facilitates the removal of water and air. The vacuum can be turned on even during the feeding, but at the latest at the beginning of the closing. During the forming process, the mold space is reduced, but not closed as in the actual pressing after forming. The stroke length of the mold is adjusted according to the target thickness of the product either by measuring the pressure in the mold space with mechanical stops or by the position of the mold. In addition, the product can be kept under vacuum on the surface of the desired mold to form a further layer on the selected side of the previous layer.

[0029] During the compression process, the foam of the next layer is exchanged through the quick valve opening to the next mold opening, where the foam of the next layer is supplied.

[0030] Surprisingly, the shaping is carried out without heating, in order to control the best foam structure for uniform shaping of the product. In practice, the shaping is carried out at a constant operating temperature, advantageously between 15 and 45 degrees Celsius. This temperature is maintained throughout the foam system, in addition to the pair of moulds, to ensure, for example, the best foam size for product quality and the life of the foam becomes longer. In addition, air is easier to remove than steam, and the layer remains intact and the operation remains stable. In practice, the foam contains more than 50%, advantageously 55% to 75% of air.

[0031] The fiber is able to achieve the optimal bubble size for high quality forming during use. Generally, the optimal bubble size of the foam during forming is about 10μm-500μm in diameter, preferably 50μm-150μm. In addition, the freshness and constant quality of the foam are ensured by continuously recycling the supplied foam near the foam generator of the foam tank. In fact, the foam generator is a tank with a built-in stirring device. Figure 1a and Figure 1b As shown, the foam of each layer is circulated to the mold and returned to the foam tank through its own pipeline. In addition, the water sucked out from the mold can be circulated back to the water tank in its own pipeline.

[0032] Surprisingly, the foam treatment achieves both high concentration and good forming compared to the aqueous slurry forming of the prior art. The water-based treatment requires higher heat and dewatering time, with much lower concentrations, and poorer forming due to flocculation. The less water used in the foam treatment can be removed more easily from smaller openings. Preferably, the mold surface can be permeable to gas through small capillaries or even from holes that are not sufficiently permeable for aqueous slurry treatment. This can improve product quality by reducing pore marks or even completely removing pore marks from the product surface. The layered product is formed by layers stacked up and down, in which case the pressing and dewatering is carried out by the previous layer or the layer below it next to the mold, and the layer structure is combined in a hot press at the latest. The layered product can be formed in an optional layer sequence. In other words, the forming can start from the middle layer or from one of the surface layers.

[0033] High-speed layering is achieved by servo-controlled valves, in which case the foam supply valve, air valve and water removal valve can be operated quickly and accurately in sync. The vacuum system is also arranged in close proximity to the mold to ensure fast operation. During forming, the adhesion of the layers to each other is ensured by removing water through the layer interface. Bonding continues during the subsequent hot pressing process, where the heat and steam generated in the product and the steam driven through the boundary layer also strengthen the adhesion of the layers to each other. The same fibers can be used for layering, but different additives can be used in different layers. The equipment forms a product blank containing several products, which is preferably uniform for transfer to further operations. The product blank can be supported for hot pressing and conveyed onwards from there. After transferring the product blank, before forming, it is best to spray the mold with water. By explaining how to improve any product properties at each stage, the properties of the next formed product (such as surface properties) will be further affected at each stage in further processing.

[0034] The first hot press removes water from the product in the form of water and partly in the form of steam. The hot smoothing die provides a second smooth surface for smoothing the second surface of the product. The counterpart has a vacuum in the direction of water removal. The second hot press evaporates the remaining moisture applied to the other surface from the product and provides a smooth surface to the product surface of the product. There are also some application tools that can be used to treat or trim the layers or surfaces of the product to adapt to different end-use requirements. The treated surface of the product is dried in a non-contact and fast manner (preferably using hot air or radiant heating) by a drying device. The actual product is separated from the product blank by punching or cutting and automatically packaged. High-quality products have several layers. The manufacture of these products takes time, but the benefits are better.

[0035] The accompanying drawings show an apparatus for forming a molded fiber product. The apparatus comprises a foam generator 23 for forming a foam from fibers, water, air and a foaming chemical. As mentioned above, the properties of the foam may vary. In addition, the apparatus comprises a mold pair 11 of a mold 12 and a mold 13, the mold 12 and the mold 13 being at a variable distance. In other words, the distance between the molds can be changed. In practice, after the foam is supplied, the molds are pressed together to remove water and air, thereby forming the product.

[0036] Furthermore, the apparatus comprises a device 24 for feeding foam between the mold 12 and the mold 13 to form the layer 10. A single layer can form the product, but advantageously the product comprises several layers, which is now possible with the apparatus according to the invention. According to the invention, as part of the device 24, one of the molds 12 or 13 has several transverse channels 19, which are arranged to be open between the molds 12 and 13. In this way, the foam is fed quickly and evenly. Furthermore, the mold pair 11 is sealed from its sides. Then, the foam can be fed even when the molds are separated and during movement. This shortens the operating cycle and provides more options when adjusting the operation and the product.

[0037] For sealing, the mold pair 11 has an outer sleeve 25, which is arranged to seal the mold pair 11 even if the mold 12 and the mold 13 are at a certain distance from each other. In this way, a closed mold space is formed, and a large amount of foam can be supplied to the mold space (which is similar to a closed cavity). Advantageously, the outer sleeve 25 is adjustable relative to the mold pair 11. Therefore, when the product is removed and transferred to the hot press, the sleeve can slide and leave space for the product. There can be a common sleeve, or both molds have their own sleeve.

[0038] The foam generator 23 is arranged near the mold pair 11. The foam then retains its shape until it reaches the mold space. In practice, the foam generator with its tank is less than 20 meters from the mold pair, advantageously less than 10 meters. Furthermore, the foam generator 23 is connected to the transverse channel 19 via the manifold 26 through the inlet 18. Figure 3a As shown, each transverse channel 19 has its own inlet 18. There are seven inlets here. When the inlets are located on both sides, there is enough space for the inlets and their connections. The foam is evenly distributed to all transverse channels via the manifold.

[0039] Before the manifold 26 there is a short circulation 27 back to the foam generator 23. In this way, the foam remains of high quality. The foam can be fed to the manifold 26 by opening the feed valve 28. This takes time and the foam can be blocked from flowing to the short circulation. According to the invention, each transverse channel 19 extends over the entire mould 12 and is connected to a return conduit 20 connected to the foam generator 23. In this way, the fresh foam supply is stabilized and constantly circulated through the mould. The actual feeding will be described later. In any case, the feeding takes only a few seconds.

[0040] As shown, the device also includes one or more additional foam generators 29 independently connected to the same manifold 26. In this way, different foams can be used to shape multi-layer products. At the same time, the foam can be quickly changed from one to another, and all foam generators can be kept with foam ready for shaping. To this end, each foam generator 23 has a short circulation section 27 for the foam before the manifold 26. During supply, the short circulation section 27 is closed by a valve 30 and the supply valve is opened. In addition, the return duct 20 is connected to a return manifold 31, which has a connection back to each foam generator.

[0041] Figure 1b The former according to the invention is shown from behind. Advantageously, the device comprises two parallel mould pairs 11 connected to the same foam generator 23 but arranged to work in different stages. The further foam generator is also shared. In this way, the device is compact and fast. Figure 1b In the example, the left mold pair is closing while the right mold pair is opening. Thus, different foams can be used flexibly and the hot press can take turns getting product from both formers. On the other hand, one large foam generator can supply foam to several formers.

[0042] Advantageously, the mold pair 11 comprises an upper mold 13 and a lower mold 12. Furthermore, the upper mold 13 is movable, while the lower mold 12 is arranged fixedly, also comprising a transverse channel 19. In this way, the moving masses are minimized and the inlet can also be fixed.

[0043] During forming, the mold with a closed mold space can be separated. This can be used as a control parameter. In addition, the open mold pair provides space for the foam. In practice, the distance between mold 12 and mold 13 is 10mm-100mm, preferably 20mm-60mm. In general, the thicker the layer, the greater the distance. In addition, the diameter of the inlet 18 is 40mm-120mm, preferably 60mm-100mm. In this way, the flow speed of the foam is kept moderate. In practice, the speed is 1-3 meters per second.

[0044] As mentioned above, the mold pair 11 includes a number of partial molds 14 or sub-molds. Figure 3a In the embodiment, 24 partial molds are combined into the lower mold 12. Here, 24 plates are formed at one time. The product blank 32 is also shown in FIG. Figure 3b Here, the product blank has three layers, and the individual products are subsequently separated in operation. The mold has a frame into which different part molds or sub-molds can be changed. Thus, a wide variety of products can be formed by one device.

[0045] According to the invention, transverse channels 19 are provided between the partial moulds 14 or sub-moulds and they comprise openings 21 leading to the mould surface. In this way, each partial mould or sub-mould is uniformly filled with foam. Thus, the product is uniform and the operation is rapid. The next characteristic also affects the speed. According to the invention, the mould pair 11 comprises movable pins 22, each of which is arranged to close a corresponding opening 21 in order to control the flow of foam. In practice, the foam circulates through the mould. When the upper mould is lifted, the pins come out of the openings and the foam flows into the mould space. The filling is rapid and again when the mould pair is closed, the pins close the openings. This valving feature can be used together with an actual valve before the manifold or can be used alone. When the openings are closed, the foam can be changed. Each foam returns to its own foam generator. Thanks to the rapid valves, the mixing of different foams can be prevented or at least minimized.

[0046] After the mold space is filled with foam, water and air are removed by pressing. The mold surface is porous. Therefore, water and air can pass through the mold surface, while fibers accumulate on the mold surface. In other words, the lower mold 12 is porous and there is a collecting device 33 below. In this way, the water will fall naturally. However, the collecting device 33 includes an underpressurized water container 34 connected back to the foam generator 23. First, the collecting device 33 also collects air. The mold will then be completely emptied for the next forming. Moreover, the water flows more efficiently due to the air. Here, the water is removed from the bottom of the mold through the middle duct. In addition, the removal of water can be assisted by overpressure from the relative mold and / or by a bleed air valve at the mold end of the vacuum system. Similarly, there is its own portion in the water container for each foam. In this way, the removed water can be used again for the relevant foam generator. For this purpose, two pumps 35 are attached. In Figure 2a In FIG. 1 , the dotted line shows the negative pressure which is led to the sealed water container via the joint 36. The dashed line shows the water discharged from the mold pair.

Claims

1. An apparatus for forming a molded fiber product, the apparatus comprising: a foam generator (23) for forming foam from fibers, water, air and foaming chemicals; A mold pair (11) having molds with a variable distance between them; and a device (24) for supplying foam between the moulds to form a layer (10), characterized in that, as part of the device (24), one of the moulds has a plurality of transverse channels (19), the transverse channels (19) comprising openings (21) leading to the mould surface, the transverse channels being arranged to be open between the moulds, the mould pair (11) comprising movable pins (22), each of the movable pins being arranged to close a corresponding opening (21) to control the flow of foam, and the mould pair (11) being sealed from its sides by an outer sleeve (25), the outer sleeve being arranged to seal the mould pair (11) even when the moulds are at a certain distance from each other.

2. The device according to claim 1, characterized in that The outer sleeve (25) is adjustable relative to the mold pair (11).

3. The device according to claim 1, characterized in that The foam generator (23) is arranged near the mold pair (11) and is connected to the transverse channel (19) through an inlet (18) via a manifold (26).

4. The device according to claim 2, characterized in that The foam generator (23) is arranged near the mold pair (11) and is connected to the transverse channel (19) through an inlet (18) via a manifold (26).

5. The device according to claim 3 or 4, characterized in that Each transverse channel (19) extends over the entire lower mould (12) and is connected to a return duct (20) connected to the foam generator (23).

6. The device according to claim 3 or 4, characterized in that The apparatus comprises one or more further foam generators (29) independently connected to the manifold (26).

7. The device according to claim 6, characterized in that Each foam generator has a short circulation section (27) for the foam before the manifold (26).

8. The device according to any one of claims 1 to 4, characterized in that During forming, the distance between the dies is 10 mm - 100 mm.

9. The device according to claim 8, characterized in that The distance between the dies is 20 mm to 60 mm.

10. The device according to claim 3 or 4, characterized in that The diameter of the inlet (18) is 40 mm to 120 mm.

11. The device according to claim 10, characterized in that The diameter of the inlet (18) is 60 mm-100 mm.

12. The device according to any one of claims 1 to 4, characterized in that The mold pair (11) comprises a plurality of partial molds (14) or sub-molds.

13. The device according to claim 12, characterized in that The transverse channel (19) is arranged between the partial molds (14) or sub-molds.

14. The device according to claim 13, characterized in that The opening (21) is upward.

15. The device according to any one of claims 1 to 4, characterized in that The mold pair (11) comprises an upper mold (13) and a lower mold (12), wherein the upper mold (13) is movable, while the lower mold (12) is configured to be fixed and comprises the transverse channel (19).

16. The device according to claim 15, characterized in that The lower mould (12) is porous and has a collecting device (33) below the lower mould (12), and the collecting device (33) includes an adjacent negative pressure water container (34), which is connected back to the foam generator (23).

17. The device according to any one of claims 1 to 4, characterized in that The apparatus comprises two parallel mould pairs (11) connected to the same foam generator (23) but arranged to operate at different stages.

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