초록 ▼

A method for making a windmill blade is provided, whereby problems with glue joints and with exposure of the workers to environmentally hazardous substances are avoided. This is effected by making the windmill blade in a closed mold with a mold core (3) inside mold parts (22, 48) for formation of a

A method for making a windmill blade is provided, whereby problems with glue joints and with exposure of the workers to environmentally hazardous substances are avoided. This is effected by making the windmill blade in a closed mold with a mold core (3) inside mold parts (22, 48) for formation of a mold cavity (51), in which fiber material (45, 47) and core material (46) are placed. After applying vacuum to the mold cavity (51), matrix material (57) is injected via a filling pipe (29), which is placed at a downwardly oriented side edge of the blade during the filling. Hereby is established a flow front (61) which is used for indicating complete filling when this reaches the trailing edge of the blade and penetrates out through overflow apertures.

대표청구항 ▼

The invention claimed is: 1. A method for making a windmill blade of composite materials that include a fiber reinforced matrix material, the improvement comprising that the blade is made in one piece in a closed mold and comprising steps that provide: a removable mold core with a flexible external

The invention claimed is: 1. A method for making a windmill blade of composite materials that include a fiber reinforced matrix material, the improvement comprising that the blade is made in one piece in a closed mold and comprising steps that provide: a removable mold core with a flexible external core part wrapped around an internal, firm or workable core part and surrounded by a flexible, air-tight membrane, and outer mold parts arranged to close around the mold core for formation of a mold cavity there between, that composite material is laid on an outer mold part and/or the mold core, that at least one flow pipe is placed in the mold cavity at the side edge for injecting matrix material, that the outer mold parts are closed around the mold core and around the composite material placed in the mold cavity, that the composite material is set, that the outer mold parts are removed, and that the mold core is taken out of the shape permanent blade before or after removing the outer mold parts, wherein some of the required matrix material is used in connection with the reinforcing fibers when laying the composite material and where additional matrix material is injected via the flow pipe after closing the mold, wherein the composite material is laid around a sandwich core material for forming the blade as a sandwich structure by providing a first inner layer of fiber material on an inner side of the sandwich core material and by providing a second, outer layer of fiber material on an outer side of the sandwich core material, wherein the first layer covers at least part of a surface of the second layer or wherein the second layer covers at least part of the surface of the first layer, where the sandwich core material is used for evacuation and flow at vacuum formation of the blade as the mold cavity is subjected to vacuum whereby air is evacuated simultaneously with composite materials being pressed against the inner side of the outer mold parts due to expansion of the flexible membrane of the mold core, and where the matrix material is injected following formation of the mold cavity by vacuum. 2. A method according to claim 1, wherein the mold cavity is rotated 90 degrees, material is injected through the flow pipe now disposed at a vertical underside of the mold cavity and with a flow regulated for controlling an upwardly advancing fluid front of the matrix material so as to avoid confinement of air in the mold cavity. 3. A method according to claim 1, wherein the first, inner and second, outer layers of fiber material each have upper and lower portions, the lower portion of the outer layer of fiber material extending beyond a side edge of the mold cavity is laid on a first outer mold part, where a layer of core material and possible other core parts are placed, where the lower portion of the inner layer of fiber material extending beyond the said side edge is laid, where the mold core is placed in the layers that are laid, where the fiber material extending beyond the side edge is folded in over the mold core and the flow pipe, where the upper portion of the inner layer of fiber material, a layer of core material and the upper portion of the outer layer of fiber material are laid on the mold core, where a second outer mold part is placed in close contact with the first outer mold part, where vacuum is applied to the mold cavity and where the matrix material is injected via the flow pipe and flows to the core material and to the inner and outer layers of fiber. 4. A method according to claim 1, wherein core inserts are disposed between the layers of fiber material and are taken out of the mold together with the composite material for making a blade in which such inserts constitute structural elements in the finished blade. 5. A method according to claim 1, wherein thermal setting is used, and wherein the temperature in the composite materials of the blade are changed during the setting by using a temperature control system in at least one of the mold parts. 6. A method according to claim 1, wherein the sandwich core material is provided with through-going passages used as ducts for fluid matrix material between the two layers of fiber material. 7. A method according to claim 1, wherein injection of the matrix material is terminated when fluid matrix material is pressed out of apertures at the upwardly facing side edge of the blade. 8. A method according to claim 1, wherein the mold core is provided as a plurality of separate sections. 9. A method according to claim 3, wherein parts of the lower portions of the inner and outer layers of fiber material are put together into the upper portion of the inner or outer layer of fiber material so that overlap of fiber material occurs at the side edge. 10. A method according to claim 3, wherein at least two sealing arrangements are provided opposite the flow pipe where the second outer mold part meets the first outer mold part, so that a cavity is created between the two arrangements that may be subjected to a vacuum different from that in the mold cavity, maintaining a lower absolute pressure than in the mold cavity and preventing leakages from the surrounding air to the mold cavity. 11. A method according to claim 5, wherein the temperature control system is active during the whole or a part of the injection process. 12. A method according to claim 5, wherein the temperature control system is used to cool the mold when the exothermic heat of the setting process is in danger of raising the temperature of the mold to an undesired level. 13. A method according to claim 1, wherein the flexible membrane further comprises multiple layers. 14. A method according to claim 1, further comprising providing an airtight layer between the firm internal core part and flexible external core part. 15. A method according to claim 1, further comprising providing a flow pipe as a recess in the mold outside the blade itself. 16. A method according to claim 1, further comprising providing flow pipes and ducts integrated in the blade as well as disposed externally as recesses or tubes in the mold parts. 17. The method of claim 8, further comprising providing a shear web between separate sections of the mold core made with an inner core part and which at each side has a core support part in one or more parts and placing a shear web fiber material on each or both sides of the inner core part and core support parts. 18. The method of claim 3, wherein the mold core is provided as a plurality of separate sections, further comprising providing a shear web between separate sections of the mold core made with an inner core part and which at each side has a core support part in one or more parts and placing a shear web fiber material on each or both sides of the inner core part and core support parts, wherein the shear web fiber material extends to some extent across the inner layer of fiber material and across the mold core.