Resistance Bridge Temperature Detector for Liquefied Gas Leak Detection
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Solution Overview
Problem
Existing temperature detection systems for liquefied gas leaks, such as optical fibre distributed temperature sensing and discrete resistance temperature detectors, are expensive and limited in their ability to monitor large areas effectively, leading to inefficiencies in leak detection and potential false alarms from environmental temperature changes.
Innovation Solution
A method and apparatus using an elongate cable with two heat-sensitive elements, configured as a bridge with parallel resistance branches, to detect rapid changes in temperature by measuring voltage differences across the bridge, providing an alarm signal when the temperature change exceeds a predetermined threshold, thus allowing for cost-effective monitoring of large areas without expensive control circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical fibre distributed temperature sensing is used, then temperature measurement capability is improved, but system cost increases significantly
Solution Approach 1:
The patent replaces expensive optical fibre sensing systems with a simple resistance temperature detector that uses conventional electrical resistance principles. The detector employs a straightforward resistance measurement approach rather than complex optical sensing, dramatically reducing system cost while maintaining adequate temperature detection capability for leak identification.
Solution Approach 2:
The patent extracts the essential function of temperature detection from the complex optical fibre system and implements it through a simplified resistance-based detector. By removing the optical sensing components and using only electrical resistance measurement, the system achieves the core detection function at much lower cost.
2Device complexity
If discrete resistance temperature detectors are used, then cost is reduced, but the ability to monitor large areas is limited
Solution Approach 1:
The patent divides the monitoring area into multiple discrete detector locations positioned around the storage tank. Each detector monitors a specific zone, and collectively they provide comprehensive coverage of the entire tank surface and surrounding areas, enabling large-area monitoring through distributed sensing points.
Solution Approach 2:
The patent transitions from single-point temperature measurement to distributed multi-point measurement by arranging detectors around the storage tank perimeter and at various heights. This spatial distribution across multiple dimensions enables comprehensive monitoring of large areas while maintaining cost-effectiveness through simple resistance-based detection at each point.
3Area of stationary object
If multiple discrete temperature detectors are deployed, then coverage area is improved, but system complexity and cost increase
Solution Approach 1:
The patent combines multiple discrete resistance temperature detectors into a unified monitoring system that shares common electrical infrastructure and data processing. The detectors are electrically connected and monitored through a centralized system that integrates readings from all sensors, simplifying the overall system architecture while maintaining extensive coverage through multiple detection points.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables efficient detection of rapid temperature changes, minimizing false alarms and reducing costs by effectively monitoring temperature changes over a large area, while maintaining high sensitivity to leaks in liquefied gas containers.
Implementation Method 1
each element having a predetermined electrical resistance variation with temperature
Implementation Method 2
measuring a voltage difference across the bridge, providing an alarm signal when the temperature change exceeds a predetermined threshold
Data Source
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Figure 5
AI summary
An electrical circuit apparatus for detecting a rate of change of temperature outside of a predetermined range of rates of change of temperature comprising a bridge comprising first and second resistance branches connected in parallel, each branch comprising a first resistance connected in series with a second resistance. A meter is coupled between a first position between the first and second resistances of the first branch and a second position between the first and second resistances of the second branch. The meter is arranged to provide an output signal indicative of the voltage difference between said positions. A processor measures the output signal and stores a first measured value of the output signal at a first time and a second measured value of the output signal at a second time. The processor then compares the measured values and provides an alarm signal if the difference between said first measured value and said second measured value exceeds a predetermined threshold. The first resistance of the first branch and the second resistance of the second branch each comprise a respective heat sensitive element having a predetermined electrical resistance variation with temperature, the heat sensitive elements extending along the length of an elongate cable such that the voltage difference between said positions is indicative of the resistance of the heat sensitive elements. A method of detecting a rate of change of temperature outside of a predetermined range of rates of change of temperature using the electrical circuit apparatus is also provided. The electrical circuit apparatus is particularly suitable for detecting rapid reductions in temperature indicative of a leak from a container of liquefied gas.