Wind Turbine Tower Flange Assembly Using Pre-Positioned Stud Bolts
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Solution Overview
Problem
The existing methods for erecting wind turbine towers require excessive handling and lifting of heavy bolts at elevated positions, leading to increased time and complexity in the assembly process.
Innovation Solution
A method involving stud bolts with nuts at both ends, allowing them to be lifted and positioned with the nuts on top, reducing the need for additional lifting operations and enabling tensioning from either side, thus minimizing manual handling and lifting requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If bolts are lifted separately to the position of abutting flanges after the uppermost tower section has been lifted, then the bolts can be inserted into the bolt holes at the elevated position, but this requires at least one additional lifting operation by a crane, adding to the time required for erecting the wind turbine tower
Solution Approach 1:
The bolts are pre-positioned in the bolt holes of the lower flange before the tower section is lifted. This preliminary positioning allows the bolts to be lifted together with the tower section, eliminating the need for separate lifting operations and reducing erection time while maintaining proper bolt orientation for tensioning
2Loss of time
If bolts are positioned in the bolt holes of lower flange while the tower section is still on the ground, then the bolts can be lifted to the elevated position along with the tower section, but the bolts must be removed from their bolt holes and reinserted in a reversed manner to allow tensioning from above
Solution Approach 1:
Instead of positioning bolts with heads above the flange for lifting and then reinserting them reversed, the invention positions bolts with heads below the flange initially. The key innovation is that bolts are inserted from above through the flange thickness, with heads remaining below the flange throughout the lifting and assembly process, eliminating the need for removal and reinsertion operations
3Ease of operation
If bolts are inserted from below to position the bolt head under the flange combination, then the bolts can be tensioned from above, but this complicates the bolt handling
Solution Approach 1:
The flange structure itself serves as the insertion guide and positioning mechanism. The bolt holes are designed to receive bolts from above, and the flange thickness automatically positions the bolt heads below the flange combination without requiring complex handling equipment or procedures. The system uses its own structure to accomplish the insertion and positioning functions
Data Source
AI summary
A method for erecting a wind turbine tower is disclosed. A tower section (8) comprising a lower flange (9) and an upper flange (10), and a plurality of stud bolts (6) and nuts (7) are provided. The tower section (8) is oriented in an upright position with the lower flange (9) below the upper flange (10), and stud bolts (6) are positioned in bolt holes (12) in the lower flange (9) with nuts (7) arranged on an upper side of the lower flange (9). The tower section (8) is lifted to a mounting position on top of another tower section (13), and a flange combination is formed by aligning the bolt holes (12) formed in the lower flange (9) of the tower section (8) with bolt holes (15) formed in an upper flange (14) of the other tower section (13), while advancing the stud bolts (6) through the bolt holes (12, 15). The invention further provides a socket tool (16) for screwing nuts (7) onto stud bolts (6) in a manner which positions the stud bolts (6) correctly with respect to a flange (9).