Vacuum infusion by means of a semi-permeable membrane

Method of producing an oblong shell member made of fibre composite material by means of vacuum infusion, the method comprising:

• impregnating the fibre material with liquid polymer, and shaping the fiber composite material in a mould with a mould cavity, in which a fibre insertion (3) with a first lateral face (1) and a second lateral face (2) is placed, and where said fibre insertion further includes a plurality of fibre layers and a distribution layer (4), said distribution layer allowing a higher rate of flow for the liquid polymer than the fibre layers, a semi-permeable membrane (5) being placed opposite the first lateral face (1) of the fibre insertion, said semi-permeable membrane being substantially permeable to gasses and substantially impermeable to liquid polymer and further communicating with a vacuum source, characterized in that the distribution layer (4) is placed inside the fibre insertion (3) with fibre layers of the fibre insertion on both sides and is interrupted by a zone (6), and that the width of the zone (6) is smaller than the width of the fibre insertion (3), said zone extending in the longitudinal direction of the shell member and being positioned opposite the semi-permeable membrane (5), and in that liquid polymer is directed via inlet channels (7, 8) to the distribution layer (4), thus creating a flow front (9, 10) between the distribution layer (4) and the second lateral face (2), said flow front moving through the zone (6) towards the semi-permeable membrane (5), characterized in that the fibre insertion (3) forms a main laminate, which is a longitudinal reinforcement section in a blade shell half for a blade of a wind turbine, wherein the width of the zone (6) is at least 2 times greater than the thickness of the piece of the main laminate.