Mold device for producing prefabricated or pre-cast element of wind turbine rotor blade and method for producing such prefabricated or pre-cast element

Abstract

The invention relates to a mould device for manufacturing a prefabricated or pre-cast element of a wind turbine rotor blade and a method for manufacturing such a prefabricated or pre-cast element. Mould device for manufacturing a prefabricated or pre-cast element of a wind turbine rotor blade, comprising a mould element (3) having a mould surface (5) and at least one vacuum foil (12, 25) to be fixed to said mould element (3) wherein said mould element (3) is equipped with: at least one longitudinal receiving means (7, 7a, 7b) adapted to receive a section (17, 29) of said vacuum foil (12, 25); and longitudinal sealing means (13, 26) adapted to clamp the vacuum foil (12, 25) in a gas-tight manner in the receiving means (7, 7a, 7b).

Description

Technical Field

[0001] The invention relates to a mould arrangement for producing a prefabricated or precast element for a wind turbine rotor blade, the mould arrangement comprising a mould element having a mould surface and at least one vacuum foil to be fixed to the mould element. Background Art

[0002] Wind turbines usually comprise large rotor blades which can be manufactured using different techniques. One technique comprises the use of several prefabricated prefabricated or precast elements made of one or more fiber mats, such as glass fiber mats, and one or more core elements, if required, which are embedded in a binder matrix made of a hardened resin. These elements are manufactured in a mold device so that they have a defined shape corresponding to the shape of the blade segment. These prefabricated or precast elements are then finally arranged in a blade mold, where the final blade is manufactured.

[0003] The mold device for producing such prefabricated or precast elements comprises a mold element, which is usually arranged at a mold carrier. The mold element comprises a mold surface, which defines the shape of the element to be produced. Usually, the mold element has a valley-shaped shape or mold surface. The articles required for manufacturing the element are arranged on the mold surface. As mentioned, these articles usually include one or more fiber mats, one or more core elements (if necessary) and a resin matrix construction powder binder, which fixes the fiber mat and the core element into a given shape after heating, melting and cooling. Because the construction materials are separate and loose articles, it is necessary to fix them on the mold surface according to their arrangement. This is usually done by applying vacuum. In order to establish a vacuum, at least one vacuum foil is arranged to cover these articles, and the vacuum foil encloses an airtight cavity including the construction article or the corresponding material, in which a vacuum will be established. The covered vacuum foil needs to be fixed to the mold element in a sealed manner so that the cavity is completely airtight. If the mold element or the corresponding mold surface itself is airtight or vacuum-tight, a single vacuum foil covering the article is sufficient. If the mould element or the corresponding mould surface is not airtight or vacuum-tight, a lower first vacuum foil needs to be arranged on the mould surface and airtightly fixed or sealed to the mould surface, after which the build object is arranged on the lower vacuum foil, which is then covered by a second upper vacuum foil, which is also airtightly fixed to the mould surface. The airtight fixing is usually achieved with the aid of an adhesive butyl tape.

[0004] To create a vacuum, usually, in addition to the blade construction material, some additional porous material is arranged in the airtight cavity, which realizes a kind of ventilation layer (breezer layer) allowing air to be removed. For example, the material may include an open porous material that allows air to flow, or a three-dimensional fiber braid with an open structure, through which a vacuum can be applied.

[0005] The airtight sealing of the one or two vacuum foils using sticky adhesive butyl tape is very time-consuming and cumbersome. Moreover, when the prefabricated or precast element is finally manufactured and one or more vacuum foils are to be removed, this removal is also very time-consuming and cumbersome. In particular, the mold surface needs to be cleaned separately because some butyl tape may still stick to the mold surface, which needs to be cleaned, and this cleaning process may have a negative impact on the next manufacturing process. Summary of the invention

[0006] It is therefore an object of the present invention to provide an improved mould arrangement.

[0007] In order to solve this problem, the present invention relates to a mold device for manufacturing a prefabricated or precast element for a wind turbine rotor blade, the mold device comprising a mold element having a mold surface and at least one vacuum foil to be fixed to the mold element, the mold device being characterized in that the mold element is equipped with: at least one longitudinal receiving device, which is suitable for receiving a section of the vacuum foil; and longitudinal sealing devices, which are suitable for clamping the vacuum foil in an airtight manner in the receiving device.

[0008] The airtight fixing of the at least one vacuum foil or, if necessary, the two vacuum foils is at least partly no longer accomplished by using an adhesive tape such as a butyl tape, but by an airtight clamping mechanism. According to the invention, the mold surface is provided with at least one longitudinal receiving device, which is adapted to receive a section of the vacuum foil and a correspondingly shaped sealing device. In this case, the term "longitudinal" means that the receiving device and the sealing device are elongated, preferably linear devices, which when in place extend in the longitudinal and / or transverse direction of the mold surface or the corresponding mold element, which usually has a rectangular shape with a long longitudinal axis and a relatively short transverse axis. The receiving devices can, for example, extend completely along the longitudinal sides of the mold surface or, depending on the arrangement of the mold element, along the longitudinal sides of a frame-like section of the mold element arranged adjacent to the valley-shaped mold surface. They can also extend in the transverse direction or, for example, can completely circulate around the valley-shaped mold surface area so that the vacuum foil is clamped around its entire perimeter. According to the invention, at least a portion of the vacuum foil can be fixed and sealed by the clamping mechanism. If only some sections of the vacuum foil are clamped, other parts are fixed and sealed, for example at the top and bottom ends of the mould element, for example, by using butyl tape, wherein the butyl tape extends in the transverse direction.

[0009] As mentioned, the clamping mechanism comprises a longitudinal receiving device arranged at the mould element or the corresponding mould surface. When the vacuum foil is arranged, the vacuum foil is overlapped with a foil section over the receiving device, which is then pushed into the receiving device. Thereafter or simultaneously therewith, the longitudinal sealing device is pressed into the receiving device, thereby clamping the foil section in the sealing device, thereby achieving a gas-tight fixation.

[0010] Since the invention proposes to establish a clamping mechanism which at least partially clamps the vacuum foil to the mold element or the corresponding mold surface, or preferably completely clamps the vacuum foil to the mold element, the airtight fixation requires only a small amount of butyl tape, or preferably no butyl tape. The clamping is simple, since only the foil section and the sealing device need to be pressed into the receiving device. Thus, the sealing can be achieved quickly. Moreover, the removal is also very simple, since only the sealing device needs to be pulled out of the receiving device, after which the vacuum foil can be removed immediately. After the vacuum foil is removed, the mold element does not need to be specially cleaned, since no sticky residues are left.

[0011] Preferably, the receiving means is groove-shaped. As mentioned, the groove-shaped receiving means may extend along both longitudinal sides of the mould element and preferably also on the transverse sides, so that the groove-shaped receiving means completely surrounds the valley-shaped mould surface. When only the longitudinal sides are provided with corresponding groove-shaped receiving means, the transverse ends of the vacuum foil need to be fixed or sealed with other sealing means, such as butyl tape, whereas when the groove-shaped receiving means completely surrounds the mould surface, such butyl tape is not needed, since clamping is achieved completely around the vacuum foil edge.

[0012] Preferably, the receiving device has a circular cross section. The groove-shaped receiving device has a small slit-shaped opening followed by a circular space for receiving the foil section and the sealing device. Although other geometries such as an elliptical or egg-shaped cross section or a rectangular cross section with rounded edges are possible, as mentioned, the mold element is equipped with a receiving device. This can be achieved in two different ways. According to a first alternative, the receiving device is machined directly into the surface of the mold element. The mold element is machined using a corresponding tool such as a milling cutter so that the groove-shaped receiving device is formed directly into the mold element. According to an alternative, the receiving device is arranged as a separate receiving element attached to the mold element. In this embodiment, the receiving device is similar to a rope or core provided with a receiving groove. The rope or core can, for example, be arranged in a corresponding attachment groove machined into the mold element, or can be directly attached to the surface of the mold element. Both alternatives, namely directly machining the receiving device or arranging a separate receiving device, allow the mold element to be simply equipped with a corresponding fixed geometry. Furthermore, if two parallel groove-shaped receiving sections are needed to clamp the lower and upper foils, these two receiving sections can be provided at a common receiving device which comprises two corresponding receiving grooves and is attached to the mold element surface. Such attachment on the surface can be done by gluing.

[0013] As mentioned, the mould element can be equipped with two or more separate receiving devices in a parallel and laterally offset arrangement. If a lower and an upper vacuum foil are used, both need to be at least partially clamped. For each vacuum foil, a separate receiving device is required. The receiving device for the lower vacuum foil is arranged closer to the mould surface or valley-shaped area than the receiving device for the upper covering vacuum foil. Thus, if the receiving device extends, for example, along the longitudinal sides or edges of the mould element, two parallel groove-shaped receiving devices are provided at each side or edge, wherein two inner receiving grooves are used to fix the lower vacuum foil and two outer receiving grooves are used to fix the upper vacuum foil. The same arrangement is provided when the lateral ends are also equipped with corresponding receiving grooves.

[0014] As mentioned, the mould element being equipped with two or more separate receiving means in a parallel and laterally offset arrangement allows at least a gas-tight fixation of a first vacuum foil engaging the first receiving means with a corresponding foil section and of a second vacuum foil engaging the second receiving means with a separate foil section. However, when only an upper vacuum foil is used because the mould surface itself is gas-tight or vacuum-tight, it is also possible to fix a single upper vacuum foil to both the first and the second receiving means, such that it engages both receiving means with separate foil sections, which are clamped with separate sealing means.

[0015] According to the invention, the sealing device itself is adapted to clamp the vacuum foil segment against the wall of the receiving device. The sealing device is like a weld that clamps the foil in the groove. This provides a complete and full fit of the foil segment with the entire surface of the wall of the preferably circular receiving groove, so that the foil segment is perfectly fitted into the groove and sealed. In particular, the circular cross-section also ensures that neither the sealing device nor the foil segment can slide out of the receiving groove, because they are also fixed due to the circular undercut geometry of the groove.

[0016] According to a first alternative, the sealing device may be an inflatable hose. When deflated, the hose can simply be arranged in the receiving device or the corresponding receiving groove together with the foil section. When the hose is fully inserted, it is simply inflated, for example by using a small pump or the like, so that it widens, thereby pressing the foil section against the wall of the receiving device or the corresponding receiving groove. It is necessary to maintain the pressure in the hose in order to maintain the press fit. When the sealing device should be removed, it is only necessary to release the pressure and deflate the hose, which then collapses and can be easily removed from the receiving groove together with the foil section.

[0017] According to an alternative embodiment, the sealing device can also be a compressible cord. The elastic cord can be compressed so that it has a small or thin shape, which allows it to be inserted into the receiving device or the corresponding receiving slot. Just after this, when the compression is no longer applied, the elastic cord widens and presses the foil section against the wall of the receiving device or the corresponding slot. Furthermore, when the foil should be separated, the compressible cord can also be simply pulled out of the receiving device.

[0018] As mentioned, the or each receiving device may surround the mould element. In this embodiment, the receiving device comprises two longitudinal sections and two transverse sections connected to each other. A single sealing device, such as an inflatable hose or a compressible cord, is used for the airtight fixation of the vacuum foil. In an alternative, the or each receiving device extends at each longitudinal side of the mould. Here, only the longitudinal sides or edges of the mould element are provided with longitudinal receiving devices or corresponding receiving grooves, while at the transverse ends, other sealing devices, such as butyl tapes, are used for the airtight fixation.

[0019] The mold element can be a one-piece element, which includes, for example, a valley-shaped mold section defining a mold surface, and two longitudinal element sections, for example, directly attached to a valley-shaped middle section. With these edge sections, the mold element, for example, rests on a mold carrier. Receiving devices are arranged at these edge sections. In an alternative, the mold element can include a central member defining, for example, a valley-shaped mold surface and a frame member including the receiving device or all receiving devices, which frame member is removably arranged. In this embodiment, the mold element is a multi-part element, which includes at least two parts, namely a central member with a mold surface and a frame member, which preferably has a rectangular shape. When arranged at the mold carrier, the central element is arranged separately and fixed to the mold carrier. After arranging all vacuum foils and items and applying vacuum, the frame member can be removed together with the vacuum bag, which in this embodiment includes upper and lower vacuum foils, which are attached to the frame member in the manner of the invention so that the frame member can be used as a transfer member or a handling frame. This is possible because the vacuum bag with the vacuumized items maintains its shape due to the applied vacuum. Therefore, the vacuum bag can be lifted from the mold surface of the central member, which is still held at the mold carrier. Of course, the vacuum in the bag is still maintained, and the vacuum between the lower vacuum foil and the mold surface is released to lift the vacuum bag from the mold surface.

[0020] The invention also relates to a method for manufacturing a prefabricated or precast element for a wind turbine rotor blade using a mold device as mentioned above, the method comprising at least one step of arranging a vacuum foil below or above some element building material and attaching the vacuum foil to the mold element by arranging a section of the vacuum foil in a receiving device of the mold element and by inserting a sealing device into the receiving device, thereby clamping the section against the wall of the receiving device, wherein the vacuum foil is completely sealed towards the mold element by the sealing device or by the sealing device and some additional sealing. Therefore, the method of the invention comprises at least one step for activating or using the clamping mechanism of the invention for at least partially clamping and sealing the vacuum foil section to the mold element. Of course, when the element building item or the corresponding material is arranged and finally covered by the sealed vacuum foil, the manufacturing process continues by heating the device or the corresponding element building item directly on the mold, thereby melting the binder material, which embeds the fiber layer or the corresponding laminate and the core element such as balsa wood element in a molten resin matrix, which matrix is ​​then cooled and hardened in order to firmly fix the building material in a given shape. However, as mentioned above, when, for example, individual frame components are provided, the vacuumed device can also be removed and transferred to further processing, for example to a heating furnace, where heating is performed.

[0021] According to the method of the invention, the lower first vacuum foil can be attached to the mould element using one or more first sealing means, and the upper second vacuum foil can be attached to the mould element using one or more second sealing means. When the mould surface itself is not airtight or vacuum-tight, the lower first vacuum foil is required to provide an airtight base, while the upper second vacuum foil closes the vacuum cavity. However, when the mould surface is airtight or vacuum-tight, the lower vacuum foil is not required, but only an upper covering vacuum foil is required.

[0022] Furthermore, the vacuum foils can also be additionally fixed to each other by gluing or welding. According to this embodiment, the two vacuum foils are fixed together in an airtight manner after the vacuum has been applied. This is necessary when the vacuum bag realized by the two vacuum foils is to be removed from the mold device, while the heating and cooling processes have not yet been carried out and the component building material is not fixed. By gluing or welding the vacuum foils, the vacuum is maintained so that after opening the clamping mechanism or a corresponding other sealed fixing device, the airtight vacuum bag can be removed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. However, the accompanying drawings are only schematic diagrams designed for illustrative purposes only and do not limit the present invention. The accompanying drawings show:

[0024] Figure 1 is a schematic diagram of the mold device of the present invention, which shows the arrangement of the vacuum foil;

[0025] Figure 2 is a schematic diagram of a portion of a mold element having a receiving device according to a first embodiment;

[0026] Figure 3 is a schematic diagram of a portion of a mold element having a receiving device according to a second embodiment;

[0027] Figure 4 is a schematic diagram of a process for securing a vacuum foil segment in a receiving device using an inflatable sealing device;

[0028] Figure 5 Is in a fixed sealing position Figure 4 Arrangement;

[0029] Figure 6 is a schematic diagram of a sealing device including an inflatable hose and a valve body;

[0030] Figure 7 is a schematic diagram of the arrangement of the lower vacuum foil;

[0031] Figure 8 yes Figure 7 A cross-sectional view of the arrangement;

[0032] Fig. 9 is a schematic diagram of the arrangement of the upper vacuum foil;

[0033] Fig.10 yes Fig. 9 A cross-sectional view of the arrangement;

[0034] Fig.11 When two vacuum foils are welded together Fig.10 A partial diagram of the arrangement of

[0035] Fig.12 is based on Fig.11 Removal of welded vacuum bags;

[0036] Fig.13 is a cross-sectional view of a portion of a mold element of another embodiment having a separate frame member; and

[0037] Fig.14 It includes according to Fig.13 A schematic diagram of a mold element of a second embodiment of the present invention. DETAILED DESCRIPTION

[0038] Figure 1 A principle diagram of a mould arrangement 1 of the invention is shown, comprising a mould carrier 2 to which a mould element 3 is attached. The mould element 3 comprises a valley-shaped central section 4 with a concave mould surface 5 and at least two edge members 6 directly attached to the central member 4. The mould element 3 is a one-piece element.

[0039] The mould element 3 is provided at its upper surface with a groove-like receiving means 7, which is realized as a surrounding groove with a lateral longitudinal receiving groove 8 extending in the longitudinal direction and two receiving grooves 9 extending in the transverse direction, wherein the grooves 8, 9 are connected to each other so as to construct a complete groove-like receiving means 7 extending around the entire perimeter of the mould surface. As shown, the longitudinal grooves 8 are arranged at the side members 6, while the transverse grooves are provided at the central section 4.

[0040] Figure 1 is an exploded view showing some of the items needed to make a prefabricated or precast element. These items include, for example, a tubular "Axel net", which is, for example, a porous tube woven from polymer fibers that allows air to flow when a vacuum is applied, as explained later. The porous tube or the corresponding Axel net extends parallel to the corresponding receiving device 7.

[0041] Furthermore, a porous mat-like material 11 made as an air-permeable microporous fiber material is shown, which is placed on the mold surface 5 and can also extend over the Axel mesh. Moreover, this porous mat-like material 11 is also used to enable air flow when vacuum is applied. It should be noted that the arrangement of the Axel mesh or corresponding porous tube 10 and the porous material 11 can also be reversed.

[0042] Figure 1 Also shown is a vacuum foil 12, which covers the porous tube 6 and the porous material 11 when attached and also extends over the receiving device 7 or the corresponding grooves 8, 9. When arranged, it overlaps with the receiving device 7 and is fixed in a clamping manner therein by using a sealing device 13, for example in the form of an inflatable hose or a compressible rope or core. Similar to the surrounding receiving device 7, the sealing device 13 also surrounds the entire mold surface 5 so that the vacuum foil 12 can be clamped and sealed along its longitudinal and transverse edges. A section of the edge of the vacuum foil 12 is pressed into the groove-shaped receiving device 7 together with the sealing device 13 so that this section of the vacuum foil 12 is tightly pressed into the receiving device 7.

[0043] Figure 2 A first embodiment of an arrangement of a mould element 3 with a receiving device 7 is shown. In this embodiment, a rectangular groove 14 is machined into the surface of the mould element 3. By means of glue, a separate receiving element 15 realizing the receiving device 7 and comprising a corresponding groove 8, 9 is attached to the groove 14. As shown, the grooves 8, 9 have a circular cross section and are open via a small slit 16, through which the section of the vacuum foil 12 and the sealing device 13 are pressed into the grooves 8, 9.

[0044] Figure 3 Another embodiment is shown, in which the receiving means are arranged on the surface of the mould element 3. Again, the receiving means 7 are realized by means of a receiving element 15 provided with corresponding grooves 8, 9, which are open by slits 16. The receiving element 15 is likewise fixed to the surface of the mould element 3 by means of glue. Figure 3 The section of the vacuum foil 12 shown in FIG. 1 is likewise pushed into the grooves 8 , 9 together with a corresponding sealing device 13 , here in the form of a hose or tube.

[0045] Although Figure 2 and Figure 3 A corresponding separating contour is shown as a corresponding receiving element 15 , but it is also possible to machine the corresponding grooves 8 , 9 directly in the mold element 3 by using a milling tool or the like.

[0046] Figure 4 and Figure 5 The fixing of the vacuum foil 12 to the corresponding receiving element 7 is shown. Figure 4, the vacuum foil 12 overlaps the receiving element 7 or the respective groove 8, 9. The receiving segment 17 is arranged above the gap 16 so as to be inserted into the groove 8, 9 through the gap 16. Furthermore, a sealing device 13 in the form of an inflatable hose 18 is shown. In order to fix the vacuum foil, the segment 17 is pressed into the circular groove 8, 9 together with the inflatable hose 18. In order to make the joint gas-tight, a suitable air pressure (or fluid pressure using water, for example) is established in the hose 18, so that the hose 18, which can be made of rubber or an elastic polymer, is expanded. The pressure must be high enough so that the hose expands and completely fills the entire circular groove 8, 9, so that the segment 17 is pressed against the wall 19 of the groove 8, 9 and a gas-tight fixation is achieved, as shown in FIG. Figure 5 As long as the pressure in the hose 18 is maintained, the arrangement remains in place. When the pressure is released, the hose 18 can be pulled out of the grooves 8, 9 together with the section 17.

[0047] As mentioned, when using such an inflatable or expandable sealing device 13 or a corresponding hose 18, pressure needs to be applied. Figure 6 An embodiment for inflating the sealing device 13 is shown. It shows a sealing device 13 comprising an inflatable hose 18. The end of the hose 18 is tightly fixed to a valve body 20 having a connection 21 to which, for example, a pressure pump or the like can be connected. When the sealing device 13 is placed on top of the vacuum foil 12 and pressed into the grooves 8, 9, the receiving device 7 also comprises a container 22 for the valve body 20. This is necessary in order to have a gas-tight fit of the vacuum foil 12 at the mould element 3 also in the region of the valve body 20.

[0048] Figure 7-10 The main steps for arranging all necessary items for producing a prefabricated or precast element at the mold device of the present invention are shown. Figure 1 akin Figure 7 The arrangement of an Axel mesh or corresponding porous tube 10 and a mat-like porous material 11 at a mold element 3, which is equipped with corresponding receiving means 7 comprising longitudinal grooves 8 and transverse grooves 9, is shown in an exploded view. Furthermore, a vacuum foil 12 is shown, which in this embodiment is a first lower vacuum foil 12, since it is attached to the mold element 3 and thus forms the bottom layer of the finally constructed vacuum bag. Figure 7 Also shown is a sealing device 13 which as mentioned is an inflatable hose or a compressible string or the like.

[0049] Figure 8 The exploded view shows Figure 7 It shows a mould element 3 which, in this embodiment, comprises two separate receiving means 7a, 7b, each of which comprises a longitudinal and a transverse groove 8a, 9a and 8b, 9b, which have also been Figure 7 Shown in.

[0050] The figure also shows a porous mat-like material 11, which in this embodiment is arranged below the Axel mesh or porous tube 10. In this embodiment, the porous mat-like material 11 is placed directly on the mold surface 5, followed by a corresponding Axel mesh or porous layer 10, which in this embodiment is a layer, rather than as Figure 1 The tube in.

[0051] Furthermore, air outlets 23 are shown which are arranged below the first vacuum foil 12 and extend through the vacuum foil 12 so that air can escape from the area between the mould surface 5 or the respective mould element 3 and the first vacuum foil 12 in order to fit the vacuum foil 12 tightly to the mould surface 5 in a perfectly form-fitting manner.

[0052] The vacuum foil 12 is then finally placed on top of the described arrangement and engages with the section 17 into the first receiving device 7 a , where it is fixed with a corresponding first sealing device 13 .

[0053] Afterwards, when the vacuum has been established Figure 7 , Figure 8 When the vacuum foil 12 is firmly fixed, the element building material 24 is placed on top of the first lower vacuum foil 12, as shown in FIG. Fig. 9 The material comprises a mat or layer of fibres, ie a laminate element, and if required some core material made of balsa wood or foam etc., and a binder or bonding agent, preferably in powder form, distributed over the whole area.

[0054] On top of the element building material 24 a second upper vacuum foil 25 is arranged which completely overlaps the building material 24 and also the lower first vacuum foil. It also overlaps the second receiving means 7b with the still uncovered grooves 8b, 9b into which it is fixed using a second sealing means 26 which is preferably identical to the sealing means 13.

[0055] Fig.10 The exploded view of shows this arrangement. Already vacuum-fixed at the mould element 3 is a first vacuum foil 12, below which the porous mat-like material 11 and the porous material 10 are arranged. The building material 24 is placed on the first vacuum foil 12 together with some additional porous material 27, which overlaps the building material 24. The porous material 27, which is also in mat-like form in this embodiment, is coupled to a further air outlet 28, which finally extends through the second vacuum foil 25 and through which the air between the first vacuum foil and the second vacuum foil 25 is discharged.

[0056] Finally, a second upper vacuum foil 25 is put in place, which overlaps the arrangement below it and also overlaps the outer second receiving device 7b with its open grooves 8b, 9b, into which the foil sections 29 and the second sealing device 26 are pressed. Finally, the sealing device 26 is for example pressurized so that the foil sections 29 are firmly clamped against the walls of the grooves 8b, 9b. Since the vacuum bag realized by the two vacuum foils 12, 25 is now built and airtightly fixed to the mold element 3, a vacuum can be established between the vacuum foils 12, 25 through the air outlet 28 again using a corresponding pump or the like, so that the vacuum chamber between the vacuum foils 12, 25 is evacuated, thereby firmly fixing the building material 24, 28 in its respective position.

[0057] Further processing of the building material 24 can be done directly in the mold device by heating the building material 24 for melting the resin binder material into which the glass fiber mat or core material etc. is embedded. Afterwards, the resin cools and hardens so that a rigid prefabricated or precast element is built. After that, the upper vacuum foil 25 is removed simply by reducing the pressure in the second sealing device 26 and pulling it out of the receiving device 7b, after which the vacuum foil 25 can be removed and the hardened prefabricated or precast element can be taken out of the mold.

[0058] The heating and cooling process may also be performed at another station. In order to transport the building material 24 arranged in the vacuum bag to this station, it is necessary to ensure that the vacuum in the vacuum bag is maintained when the vacuum bag is lifted from the mold surface 5. To ensure this, Fig.11 and Fig.12 The following possibility is shown: the lower vacuum foil 12 and the upper vacuum foil 25 are welded together along their overlapping edges to produce a gas-tight weld seam 30 extending completely around the overlapping edges, such as Fig.11 and Fig.12 This can be done by heat welding or ultrasonic welding etc. Instead of welding, sandwich butyl tape can also be used for this purpose.

[0059] After the vacuum bag has been hermetically closed, the pressure in the two inflated sealing devices 13, 26 is reduced so that they can be removed, e.g. Fig.12 Thereafter, the complete vacuum bag 31 including the build material 24, which maintains its shape due to the applied vacuum, can be lifted and removed.

[0060] Fig.13An embodiment of a mold element 3 is shown, which comprises a central valley-shaped member 32 having a mold surface 5, where the building material 24, etc. is arranged. The mold element 3 also comprises a frame member 33, which has a rectangular shape and extends along the longitudinal and transverse edges of the central member 32. Receiving devices 7a, 7b are arranged at this frame member 33, see Fig.13 , the foil sections 17, 29 are clamped in the receiving devices 7a, 7b by means of sealing devices 13, 26. Since the vacuum bag 31 is likewise constructed by means of a lower first vacuum foil 12 and an upper second vacuum foil 25, which are likewise welded together as previously described, and since the entire interior of the vacuum bag 31 can be evacuated, the complete vacuum bag 31 with the vacuumized building material 24 can be removed by lifting the frame member 33 from the mold carrier 2, where only the central member 32 remains. It is only necessary to remove the vacuum between the mold surface 5 and the lower vacuum foil 12, if present. The frame member 33 is thus a handling frame that allows the vacuum-fixed building material 24 in the vacuum bag 31 to be transported. The arrangement can then be stored until it is further processed, or can be moved directly to another processing station, where it is heated and cooled, etc.

[0061] In addition to its use for the production of prefabricated elements based solely on essentially dry material, the vacuum sealing or clamping method of the invention is also suitable for casting resin-based composite parts under conditions where a vacuum is established in a vacuum bag, into which resin can then be introduced via appropriate inlet (and outlet) hoses, for example by resin injection into the vacuum bag cavity, to produce fiber-reinforced composite parts.

[0062] Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the disclosed examples, from which a skilled person will be able to derive other variations without departing from the scope of the present invention.

Claims

1. A mould arrangement for producing prefabricated or precast elements for wind turbine rotor blades, comprising a mould element (3) having a mould surface (5) and at least one vacuum foil (12, 25) to be fixed to the mould element (3), characterised in that The mould element (3) is equipped with at least one longitudinal receiving device (7, 7a, 7b) adapted to receive a section (17, 29) of the vacuum foil (12, 25) and longitudinal sealing means (13, 26) adapted to clamp the vacuum foil (12, 25) in an airtight manner in the receiving device (7, 7a, 7b).

2. The mold device according to claim 1, characterized in that: The receiving device (7, 7a, 7b) is groove-shaped.

3. The mold device according to claim 2, characterized in that: The receiving device (7, 7a, 7b) has a circular, oval or egg-shaped cross section or a rectangular cross section with rounded edges.

4. A mould arrangement according to any one of the preceding claims, characterised in that The receiving means (7, 7a, 7b) are either machined directly into the surface of the mould element (3) or the receiving means (7, 7a, 7b) are provided at a separate receiving element (15) attached to the mould element.

5. A mould arrangement according to any one of the preceding claims, characterised in that The mould element (3) is provided with two or more separate receiving devices (7a, 7b) in a parallel and laterally offset arrangement.

6. The mold device according to claim 5, characterized in that The vacuum foil (12, 25) is adapted to engage the separate receiving devices (7a, 7b) with separate sections, or at least a second vacuum foil (25) is provided, wherein the first vacuum foil (12) engages the first receiving device (7a) and the second vacuum foil (25) engages the second receiving device (7b).

7. A mould arrangement according to any one of the preceding claims, characterised in that The sealing device (13, 26) is adapted to clamp a vacuum foil section (17, 29) against a wall (19) of the receiving device (7, 7a, 7b).

8. The mold device according to claim 7, characterized in that The sealing device (13, 26) is an inflatable hose (18), or the sealing device (13, 26) is a compressible string.

9. The mold device according to claim 8, characterized in that: The sealing device (13, 26) includes a valve element (20) for inflating and deflating the hose (18).

10. A mould arrangement according to any one of the preceding claims, characterised in that The or each receiving device (7, 7a, 7b) surrounds the mould element (3), or the or each receiving device (7, 7a, 7b) extends at each longitudinal side of the mould element (3).

11. A mould arrangement according to any one of the preceding claims, characterised in that The mould element (3) comprises a central component (32) defining the mould surface (5) and a frame component (33) comprising the receiving means (7, 7a, 7b) or all the receiving means (7, 7a, 7b), the frame component (33) being removably arranged.

12. Method for manufacturing a prefabricated or precast element for a wind turbine rotor blade using a mould device (1) according to any of the preceding claims, comprising at least one of the following steps: arranging a vacuum foil (12, 25) below or above some element building material (24) and attaching the vacuum foil (12, 25) to the mould element (3) by arranging a section (17, 29) of the vacuum foil (12, 25) in a receiving device (7, 7a, 7b) of a mould element (3) and by inserting a sealing device (13, 26) into the receiving device (7, 7a, 7b) so as to clamp the section (17, 29) against a wall (19) of the receiving device (7, 7a, 7b), wherein: The vacuum foil (12, 25) is completely sealed towards the mould element (3) by the sealing means (13, 26) or by the sealing means (13, 26) and some additional sealing.

13. The method according to claim 12, characterized in that A lower first vacuum foil (12) is attached to the mould element (3) with one or more first sealing means (13) and an upper second vacuum foil (25) is attached to the mould element (3) with one or more second sealing means (26).

14. The method according to claim 13, characterized in that The vacuum foils (12, 25) are fixed to each other by gluing or welding.

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