Flowmeter Strain Gage Detection for Primary Containment Failure
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Solution Overview
Problem
Existing flowmeter systems face challenges in detecting internal leaks without complex installations and costly regulatory approvals, and temperature fluctuations can cause false leak detections using pressure transmitters.
Innovation Solution
A flowmeter system utilizing strain gages to detect primary containment failure by measuring resistance changes, connected in series with the drive mechanism, allowing for simple and cost-effective leak detection without additional wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure transmitters are used to detect internal leaks, then leak detection capability is provided, but device complexity and installation complexity increase
Solution Approach 1:
The strain gage is integrated into the existing drive coil assembly, merging the leak detection function with the existing drive mechanism. The strain gage is positioned to detect case pressure changes directly within the drive assembly housing, eliminating the need for separate pressure transmitter installation and reducing overall device complexity.
Solution Approach 2:
The strain gage utilizes the existing drive coil assembly structure and wiring to detect leaks. By integrating the detection function into the existing mechanical assembly, the system serves both driving and detection functions without requiring entirely separate systems, thereby reducing installation complexity.
2Reliability
If pressure transmitters are used for leak detection, then leak detection is enabled, but cost increases due to regulatory approvals and additional components
Solution Approach 1:
The strain gage is a relatively simple, cost-effective component compared to pressure transmitters. It provides sufficient leak detection capability through its ability to measure case pressure changes, avoiding the need for expensive pressure transmitter hardware and associated regulatory approvals.
Solution Approach 2:
The strain gage serves multiple functions: it detects case pressure changes for leak detection, and can be integrated with the existing drive coil assembly. This multi-functionality eliminates the need for separate dedicated leak detection systems, reducing overall cost.
3Reliability
If pressure transmitters are used to detect leaks, then leak detection is provided, but false alarms occur due to temperature fluctuations
Solution Approach 1:
The strain gage is positioned specifically to detect case pressure changes at the drive assembly location, where temperature fluctuations are less significant compared to external environmental factors. This localized measurement approach reduces the impact of temperature variations on detection accuracy.
Solution Approach 2:
The system can incorporate temperature compensation feedback by monitoring temperature at the strain gage location and adjusting the pressure detection threshold accordingly. This feedback mechanism allows the system to distinguish between true leaks and temperature-induced false alarms.
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
Enables reliable and cost-effective internal leak detection within flowmeters, eliminating the need for additional signal and power wires and reducing false alarms from temperature fluctuations.
Implementation Method 1
At least one strain gage is inside the case configured to detect a strain
Implementation Method 2
a drive mechanism coupled to the one or more flow tubes and oriented to induce a drive mode vibration in the one or more flow tubes
Implementation Method 3
A pair of pickoff sensors is coupled to the one or more flow tubes, and configured to measure a vibrational response of the flow tubes induced by the drive mechanism
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.