Cable Tension Measurement via Spooling Force Sensors
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Solution Overview
Problem
Current cable tension measurement systems, such as Cable Mounted Tension Devices, face reliability issues and can damage winch cables under high tension, necessitating more accurate and reliable methods for monitoring cable tension in wireline operations.
Innovation Solution
A tension measurement assembly comprising a spooling device with multi-axis force sensors and a cable sensor, along with a processor that calculates and monitors cable tension based on sensed forces and spooling/unspooling characteristics, providing a more accurate and reliable solution without the need for conventional strain gauges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Cable Mounted Tension Device (CMTD) with strain gauge is used to measure cable tension, then tension measurement is achieved, but reliability deteriorates due to strain gauge failures and cable damage risk
Solution Approach 1:
The patent extracts the measurement function from the cable itself by using force sensors on the spooling device. Instead of mounting sensors directly on the cable (CMTD approach), the system measures forces applied to the spooling device and calculates cable tension from these measurements, eliminating the need for cable-mounted strain gauges and their associated reliability issues.
Solution Approach 2:
The patent introduces the spooling device as an intermediary between the cable and the measurement system. Force sensors measure forces on the spooling device, and a processor calculates cable tension from these force measurements combined with cable sensor data, providing an indirect but more reliable measurement method that avoids direct cable contact with fragile strain gauges.
2Measurement precision
If a CMTD is used under high tension, then tension measurement continues, but harmful effects occur including cable breakage
Solution Approach 1:
The measurement system is extracted from the cable environment by placing force sensors on the spooling device instead of on the cable. This eliminates the direct contact between measurement components and the cable, removing the source of mechanical damage that occurs under high tension conditions.
Solution Approach 2:
The patent replaces the mechanical CMTD system with wheels and strain gauges with an electronic sensing system using force sensors and a processor. This substitution allows for non-contact or minimal-contact measurement that does not mechanically interact with the cable in a way that could cause damage under high tension.
Data Source
AI summary
A tension measurement assembly, for measuring and monitoring a tension force in a cable being deployed from a spooling device on which the cable is spooled, comprises at least one force sensor disposed adjacent the spooling device for sensing a force applied to the spooling device and generating a force signal representing the sensed force, and a processor responsive to the force signal for calculating and monitoring a tension force present in the cable. A cable sensor engages the deployed cable for sensing a spooling/unspooling rate and a length of the cable moving past the cable sensor in a pre-determined time period and generating a spooling signal representing the sensed rate and length to the processor for use in the calculating and monitoring of the tension force.