Flowmeter Strain-Gage Detection for Primary Containment Failure
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Solution Overview
Problem
Existing flowmeter systems face challenges in detecting internal leaks within the flowmeter case, which are not immediately apparent and require complex installations and costly regulatory approvals, often leading to false alarms due to temperature fluctuations.
Innovation Solution
A flowmeter system utilizing strain gages connected in series with the drive mechanism to measure resistance changes, indicating primary containment failure by comparing resistance to a baseline, and triggering alarms or halting operations when a predetermined resistance deviation is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional leak detection methods are used, then containment failure detection is achieved, but installation complexity and cost increase due to additional wiring and regulatory approvals
Solution Approach 1:
The strain gage serves multiple functions: it is part of the drive mechanism circuitry and simultaneously detects containment failure through resistance changes. This eliminates the need for separate detection wiring, reducing installation complexity while maintaining leak detection capability.
Solution Approach 2:
The existing drive mechanism wiring automatically serves the dual purpose of powering the drive mechanism and detecting containment failures. The system uses its own existing infrastructure without requiring additional dedicated detection systems, thereby simplifying installation.
2Reliability
If traditional pressure-based detection is used, then containment failure is detected, but false alarms increase due to temperature fluctuations
Solution Approach 1:
The patent replaces pressure-based detection with electrical resistance-based detection using strain gages. This substitution eliminates the sensitivity to temperature fluctuations that plagues pressure-based systems, as the strain gage resistance changes are measured relative to a baseline and are not significantly affected by temperature variations.
Solution Approach 2:
The detection method changes from monitoring pressure parameters to monitoring electrical resistance parameters. By measuring resistance changes of the strain gage against a baseline resistance, the system achieves more stable and reliable detection that is less susceptible to environmental interference such as temperature fluctuations.
3Reliability
If additional detection equipment is installed, then leak detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The strain gage is integrated into the existing drive mechanism circuitry, serving both as part of the drive system and as a containment failure sensor. This multi-functionality eliminates the need for additional detection equipment, maintaining improved detection capability while avoiding increased system complexity.
Solution Approach 2:
The detection function is merged with the existing drive mechanism wiring and strain gage components. By combining the drive mechanism and detection functions into a single integrated system, the patent avoids adding separate detection equipment, thereby maintaining simplicity while improving reliability.
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
Provides reliable and cost-effective leak detection within the flowmeter case without the need for additional wiring, reducing installation complexity and false alarms, and maintaining integrity of flow and density measurements.
Implementation Method 1
At least one strain gage is inside the case configured to detect a strain. The meter electronics is configured to measure a resistance of the strain gage, and compare the resistance of the strain gage to a baseline resistance
Implementation Method 2
A driver, such as a voice-coil style driver, applies a force to the one or more fluid tubes. The force causes the one or more fluid tubes to oscillate
Data Source
AI summary
A flowmeter is provided that includes a sensor assembly and meter electronics configured to detect a containment failure within a flowmeter case. One or more flow tubes and a drive mechanism are coupled to the one or more flow tubes and oriented to induce a drive mode therein. A pair of pickoff sensors is coupled to the flow tubes and configured to measure a vibrational response induced by the drive mechanism. At least one strain gage is inside the case, and configured to detect strain. The meter electronics is connected to the drive mechanism and the at least one strain gage, and are connected in series. The meter electronics is configured to measure a resistance of the strain gage, and compare the resistance to a baseline resistance. A primary containment failure is indicated if the resistance of the strain gage is different from the baseline resistance by a predetermined amount.