Slippage Sensor for Integrated Power Tong
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Solution Overview
Problem
Integrated power tong and back-up tong systems face damage due to slippage between the tubular string and the back-up tong during make-up or break-out operations, leading to unwanted displacement and potential equipment damage.
Innovation Solution
An automated system that senses lateral or rotational displacement of the back-up tong relative to the power tong or frame, disabling the power tong operation when a predetermined threshold is exceeded, thereby preventing damage by disengaging the jaws and allowing realignment before re-engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the back-up tong grips the tubular string during high-torque operations, then the tong can apply counter-torque to stabilize the system, but the tong may slip relative to the tubular string causing unwanted displacement and equipment damage
Solution Approach 1:
The patent applies preliminary action by positioning a stop element on the back-up tong that prevents excessive lateral displacement before it can occur during slippage events. The stop element is pre-configured to limit the movement range, ensuring that even if slippage occurs, the displacement remains within safe boundaries that prevent equipment damage.
Solution Approach 2:
The stop element acts as a cushioning mechanism that absorbs and limits the harmful effects of slippage. By providing a physical barrier that prevents excessive displacement, the stop element cushions against potential damage to the tong, tubular string, and surrounding equipment during slippage events.
2Power
If the power tong applies high torque to make-up or break-out connections, then the connection can be secured or disconnected, but reaction forces cause unwanted displacement of the tong system
Solution Approach 1:
The patent applies the counterweight principle by using the back-up tong to provide counter-torque that balances the reaction forces generated by the power tong. The back-up tong grips the tubular string and applies an equal and opposite torque, effectively canceling out the reaction forces that would otherwise cause unwanted displacement of the power tong system.
Solution Approach 2:
The back-up tong acts as an intermediary element between the power tong and the tubular string. It transfers and balances the reaction forces through its grip on the tubular string, preventing these forces from directly displacing the power tong system. The stop element further mediates by limiting any residual displacement.
3Adaptability or versatility
If slippage of the back-up tong is allowed to occur, then the tong can accommodate variations in tubular grip, but excessive displacement can damage the integrated tong system
Solution Approach 1:
The stop element is pre-positioned on the back-up tong to establish a maximum displacement limit before slippage can cause damage. This preliminary configuration ensures that while the tong can accommodate normal grip variations through limited slippage, excessive displacement is prevented from the outset.
Solution Approach 2:
The stop element provides beforehand cushioning by serving as a physical barrier that absorbs the energy of excessive displacement. It allows controlled slippage for adaptability while cushioning against uncontrolled movement that would lead to equipment damage.
Data Source
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AI summary
Method and apparatus to make-up or break-out a threaded tubular connection using an integrated power tong and back-up tong (10). The power tong (20) may be disabled upon sensing a predetermined threshold amount of displacement of at least a portion of a back¬ up tong (14). The sensed displacement indicates that the back-up tong (14) is slipping, and power tong (20) rotation may be disabled to prevent damage to the pipe string (16) or surrounding equipment. A slippage sensor (40) may be disposed to sense displacement of at least a portion of the back-up tong (14) relative to a supporting frame (12). In one embodiment, the slippage sensor (40) may be operatively coupled to a valve (50) disposed in communication with a fluid line (46) supplying power fluid to the power tong (20). The power tong (20) may be disabled by impairing flow to the power tong (20) upon sensing a predetermined displacement of the back-up tong (14).