Annular Flange Bolt Tightening Using Gap-Guided Sequencing
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Solution Overview
Problem
In wind power plant tower connections, irregular gaps between annular flanges due to production-related tolerances lead to incomplete axial contact, necessitating an alternative method for tightening screw connections to achieve uniform pretensioning and gap closure.
Innovation Solution
A method involving a tool carrier that detects and records gap sizes between annular flanges, identifies the largest gap, and systematically tightens screw connections at corresponding positions, ensuring consistent spacing and eventual gap closure using a control and evaluation unit, potentially aided by a laser scanner and rollers for precise movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional tightening methods are used on flanges with irregular gaps, then the tightening process can be completed, but uniform pretensioning force cannot be achieved and gaps remain between flanges
Solution Approach 1:
The system performs preliminary scanning of the flange gap profile before tightening to identify the largest gap location. This preliminary detection allows the control system to plan the tightening sequence in advance, ensuring that bolts are tightened in an order that progressively closes the gap while maintaining uniform pretensioning force throughout the process.
Solution Approach 2:
The system continuously monitors the gap size at each bolt position during the tightening process and uses this feedback information to adjust the tightening sequence and force distribution. The control unit processes real-time gap measurements to determine optimal tightening strategies, ensuring uniform pretensioning is achieved despite initial gap irregularities.
2Measurement precision
If multiple scanning passes are performed to detect gap profile, then detection accuracy improves, but measurement time increases
Solution Approach 1:
The system performs a preliminary scanning pass to obtain an initial gap profile before tightening begins. This preliminary measurement provides sufficient information to plan the tightening sequence without requiring multiple redundant scans. The initial gap profile is used to identify the largest gap location and determine the optimal starting point for the tightening process.
Data Source
AI summary
For tightening screw connections disposed along two annular flanges to be tensioned relative to one another and forming a ring, a tool carrier movable along the ring has a tool and a sensor. It is moved along the ring at least once, wherein current longitudinal positions of the tool carrier relative to the ring are repeatedly detected as position values and the gap size between the annular flanges at the respective current position is repeatedly detected as a gap size value by the sensor. These values are transmitted to a control and evaluation unit storing gap size values conjointly with assigned position values as datasets and determining, based on the datasets, the largest or an above-average gap size value together with assigned position value as a primary position. The screw connection at the primary position or a directly adjacent one in circumferential direction is tightened by the tool.