Planar Vibratory Viscometer Cantilever Projections Gas Viscosity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas viscosity measurement techniques face challenges due to high compressibility of gases, which affects the accuracy of viscosity determination, especially with unwanted mechanical and acoustic resonances interfering with the resonance of vibrating elements.
Innovation Solution
A planar vibratory member with cantilevered projections is used in a viscometer, designed to avoid unwanted resonances by careful geometry and placement, allowing for precise measurement of the quality factor (Q) and resonant frequency to determine gas viscosity accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional vibrating element is used for gas viscosity measurement, then the measurement can be performed, but unwanted mechanical and acoustic resonances interfere with the resonance of the vibrating element, reducing measurement accuracy
Solution Approach 1:
The planar vibratory member is segmented into multiple vibratable projections (typically three) extending from a common support structure. Each projection can vibrate independently, allowing the system to achieve the desired resonant frequency while avoiding unwanted mechanical and acoustic resonances that plague traditional single-element designs. This segmentation enables precise control over the vibrational characteristics of the sensor.
Solution Approach 2:
The invention transitions from traditional three-dimensional volumetric vibrators to a two-dimensional planar structure. This dimensional reduction eliminates unwanted acoustic resonances within the vibratory member itself, as the planar geometry prevents standing wave patterns that occur in volumetric structures. The planar configuration allows the member to vibrate in a controlled manner without internal resonant interference.
2Measurement precision
If the vibratory member geometry is optimized to avoid unwanted resonances, then measurement accuracy improves, but the device complexity increases due to careful geometry and placement requirements
Solution Approach 1:
Different regions of the planar vibratory member are designed with specific local properties: the vibratable projections have optimized dimensions and spacing to achieve desired resonant frequencies, while the support structure is designed to minimize unwanted modes. This local optimization allows each part to contribute specifically to avoiding unwanted resonances while maintaining overall simplicity.
Solution Approach 2:
The planar vibratory member employs asymmetric geometry in the arrangement of vibratable projections relative to the support structure. This asymmetric configuration helps eliminate symmetric vibration modes that could create unwanted resonances, while still maintaining a relatively simple overall structure that is easier to manufacture than fully symmetric complex designs.
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 design achieves superior accuracy in gas viscosity measurement by eliminating unwanted resonances and providing a simpler relationship between damping and viscosity, enhancing the precision over prior art sensors.
Implementation Method 1
Measurement of gas viscosity can be very useful; it can be used directly to determine Reynold's number and hence determine correction factors for Orifice and Turbine Gas flowmeters. Meters that utilize mechanical resonators, such as vibratory tuning forks, have found some success in the field of viscosity measurement.
Implementation Method 2
viscosity is determined by measuring the quality factor (Q) of the resonance and hence damping of the resonator
Implementation Method 3
The principle of using a vibrating sensor for measurement of liquid viscosity is well known. The above equation has been shown to work well for most liquid viscosity measurement applications. The situation with regard to gas measurement is slightly different due to the fact that gases have a much higher compressibility
Data Source
AI summary
A viscometer (700) is provided, for determining a viscosity of a gas therein. The viscometer (700) comprises a driver (704) and a planar vibratory member (500, 600) vibratable by the driver (704), that comprises a body (502) and a vibratable portion (504) emanating from the body (502), wherein the vibratable portion (504) comprises a plurality of vibratable cantilevered projections. At least one pickoff sensor (706) is configured to detect vibrations of the vibratory member (500, 600). Meter electronics (900) comprise an interface (901) configured to send an excitation signal to the driver (704) and to receive a vibrational response from the at least one pickoff sensor (706), measure a Q and resonant frequency of the planar vibratory member (500, 600), and to determine a viscosity (923) of the gas therein using the measured Q and the measured resonant frequency.