Compact Vibratory Flowmeter for Cement with Low Drive Frequency
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Solution Overview
Problem
Existing compact vibratory flowmeters face challenges in accurately measuring flow characteristics of multi-phase flow materials, particularly when gas is entrained, leading to erroneous readings due to increased stiffness and resonance frequency issues, which are exacerbated in applications with limited physical space.
Innovation Solution
A compact vibratory flowmeter design featuring a drive frequency less than 200 Hertz, a frequency ratio of less than 0.8 to the fluid resonant frequency, and a high aspect ratio, along with self-draining bowed flow conduits, to maintain measurement accuracy and reliability even with entrained gas, specifically optimized for cement flow materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the flowmeter is scaled down to reduce size, then the physical space requirement is reduced, but the stiffness of the flow conduit increases significantly
Solution Approach 1:
The patent changes the drive frequency parameter from typical high frequencies (300-500 Hz) to a lower frequency range (below 200 Hz). This parameter change allows the scaled-down conduit to operate at a frequency where the increased stiffness does not cause resonance issues, thereby resolving the contradiction between reduced size and increased stiffness
Solution Approach 2:
The patent makes the drive frequency adjustable and adaptive rather than fixed. The system can dynamically adjust the drive frequency to maintain optimal operation below 200 Hz, allowing the flowmeter to adapt to the changed stiffness characteristics of the scaled-down conduit while maintaining measurement accuracy
2Speed
If the drive frequency is increased due to increased conduit stiffness, then the flowmeter responds faster, but the measurement accuracy degrades when gas is entrained in the flow material
Solution Approach 1:
The patent deliberately changes the drive frequency parameter to be below 200 Hz, which is lower than typical flowmeters. This ensures that even when gas is entrained in the flow material and lowers the resonant frequency, the drive frequency remains sufficiently below resonance to maintain measurement accuracy while still providing adequate response speed
Solution Approach 2:
The patent skips over the problematic high-frequency range where resonance issues occur with entrained gas. By operating in the lower frequency range below 200 Hz, the system avoids the resonance region entirely, preventing accuracy degradation while maintaining acceptable response characteristics
3Shape
If a U-shaped flow conduit is used, then the flowmeter has a compact form factor, but the aspect ratio is low requiring large vertical physical space
Solution Approach 1:
The patent transitions from a U-shaped configuration (which requires vertical space) to a straight flow conduit configuration. This dimensional change allows the flowmeter to achieve compactness in the vertical dimension while maintaining the necessary flow path length, effectively resolving the contradiction between compact shape and vertical space requirements
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
The solution provides accurate measurement of flow characteristics, including density, by maintaining a discernable distance from the fluid resonant frequency, reducing errors caused by entrained air, and accommodating installation in limited spaces with a compact, high-aspect-ratio design.
Implementation Method 1
The driver is configured to vibrate the one or more flow conduits. The one or more flow conduits include a drive frequency that is less than about 200 Hertz (Hz)
Implementation Method 2
motion of the conduit is measured at points spaced along the conduit. Two such transducers (or pickoff sensors) are typically employed in order to measure a vibrational response of the flow conduit or conduits
Implementation Method 3
a frequency ratio of the drive frequency to a fluid resonant frequency of the cement flow material that is less than about 0.8
Data Source
AI summary
A compact vibratory flowmeter (200) for measuring flow characteristics of a cement flow material at a cement flow material pressure of greater than about 10 pounds-per-square-inch (psi) is provided according to an embodiment of the invention. The compact vibratory flowmeter (200) includes at least two pickoff sensors (308) and a driver (309). The compact vibratory flowmeter (200) further includes one or more flow conduits (301). The at least two pickoff sensors (308) are affixed to the one or more flow conduits (301) and the driver (309) is configured to vibrate the one or more flow conduits (301). The one or more flow conduits (301) include a drive frequency that is less than about 200 Hertz (Hz) and a frequency ratio of the drive frequency to a fluid resonant frequency of the cement flow material that is less than about 0.8.