Inner covering for wind turbine blades and method for mounting same

1. A method for applying an inner covering for a wind turbine blade, comprising:

a) forming on a preforming mold, by means of precut fabrics or layers of composite materials based on glass or carbon fibers and resins that are not cured or only partially cured, a sheath with a flexible wall that is open at the root thereof and has shapes and dimensions that are about the same as the inner shapes and dimensions of the structural element of the blade;

b) preparing the inner surface of the structural element by means of introducing a tool with blasting nozzles and washing nozzles to form a clean and rough surface which facilitates adherence of the covering made up of the sheaths;

c) mounting the sheath on a support or tool which is introduced with said sheath into the blade through the open root thereof until reaching the tip of the blade;

d) arranging between the support or tool and the sheath an inflatable chamber which, by means of the inflation thereof, is capable of attaining the inner dimensions and shapes of the structural element of the blade;

e) introducing the support with the sheath and inflatable chamber into the structural element of the blade through the open root thereof, and inflating the inflatable chamber until the sheath is applied on the inner surface of the structural element of the blade;

f) curing and hardening the composite materials forming the sheath and the sheath adhering to the inner surface of the structural element of the blade.

2. The method according to claim 1 , wherein an outer peripheral channel is formed in the root of the sheath as a prolongation of the wall of said sheath, which is coupled on the edge of the wall of the blade limiting the open root thereof, the outer surface overlapping the wall of the blade a sufficient length for the assembly bolts of the blade to go through same.

3. The method according to claim 1 , wherein the sheath is formed by at least two longitudinal parts attached to one another.

4. The method according to claim 1 , wherein the tool or support, with the sheath or parts of the sheath and with the inflatable chamber, is driven through the blade by means of pulling it using cables which are extracted out through holes made at the tip of the blade.

5. The method according to claim 1 , wherein the sheath is formed on the inner surface of the structural element of the blade, on which the fabrics or layers forming said sheath are applied and compacted by means of the inflatable chamber introduced in the blade through the open root thereof.

6. The method according to claim 1 , wherein the sheath is attached to the inner surface of the blade by means of an adhesive including the composite materials forming the fabrics or layers.

7. The method according to claim 1 , wherein a reinforcement adhesive is furthermore applied for attaching the sheath to the inner surface of the blade.

8. The method according to claim 1 , wherein in blades the structural element of which has a balancing block, before introducing the support with the sheath and inflatable chamber into the structural element of the blade, the balancing block is extracted from the inside of said structural element.

9. The method according to claim 1 , wherein the composite materials forming the sheath are cured and hardened by means of blowing hot air through the open root of the blade.

10. The method according to claim 1 , wherein the composite materials forming the sheath are cured and hardened by means of electric heating blankets arranged between the inflatable chamber and the fabrics of composite materials forming said sheath.

11. The method according to claim 1 , wherein the composite materials forming the sheath are cured and hardened by means of electric heating blankets arranged on the shells in the area of adherence to the structural element.

12. The method according to claim 8 , wherein the balancing block is extracted by means of detaching it from the inner surface of the structural element of the blade by applying heat on the faces of said block, and pulling the block through the open root of the blade.

13. The method according to claim 8 , wherein the balancing block is extracted by means of cutting the layer of adhesive attaching the balancing block to the walls of the structural element of the blade and then pulling said block through the open root of the blade.