Resonant Sensor for Conductive Fluids Using Balanced Capillary Tube
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Solution Overview
Problem
Existing vibrating wire viscometers are limited in measuring conductive fluids and face challenges with temperature-dependent resonant frequency due to insulation issues and mechanical vulnerability, particularly in high-pressure applications like downhole drilling.
Innovation Solution
A resonant fluid properties sensor using a vibrating capillary tube with an electrical conductor inside, where a solid material fills the space between the conductor and the tube to transmit forces directly, and a balanced resonator configuration to minimize energy leakage and temperature effects, allowing for hermetic sealing and operation in extreme conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conductive wire is used for measuring fluid properties, then the resonant frequency and damping can be measured to determine density and viscosity, but the wire becomes vulnerable to mechanical damage from particles in the fluid and corrosion from conductive fluids
Solution Approach 1:
The patent applies this principle by replacing the thin conductive wire with a thicker elastic capillary tube that is mechanically robust against particle damage and corrosion. The capillary tube serves as a flexible shell that can withstand extreme conditions while still enabling resonance-based measurement of fluid properties through its wall vibrations.
Solution Approach 2:
The patent uses composite material construction by combining the elastic capillary tube with an internal electrical conductor. This composite structure provides both the mechanical strength needed to resist corrosion and particle impact, and the electrical conductivity required for exciting and sensing the resonant vibrations, thereby resolving the vulnerability issue while maintaining measurement capability.
2Reliability
If insulating material is applied to the wire to prevent corrosion, then the wire is protected from conductive fluids, but the resonant frequency becomes temperature-dependent due to thermal expansion differences
Solution Approach 1:
The patent extracts the electrical conduction function from the elastic structure by placing the conductor inside the capillary tube. This separation allows the elastic tube to be made of corrosion-resistant material without insulating coatings that would cause thermal expansion issues, while the internal conductor provides the necessary electrical functionality for resonance excitation and sensing.
Solution Approach 2:
The patent introduces an intermediary approach by using the internal conductor as a mediator between the elastic capillary tube and the external measurement system. The conductor transmits the resonant vibrations from the tube wall to the measurement electronics, eliminating the need for insulating coatings on the tube while maintaining electrical functionality.
3Measurement precision
If the wire is made thinner to reduce mass and increase sensitivity, then the resonant frequency increases and measurement sensitivity improves, but the wire becomes more vulnerable to mechanical damage
Solution Approach 1:
The patent applies this principle by using a thicker elastic capillary tube instead of a thin wire. The capillary tube's greater thickness provides mechanical strength to resist particle impact and corrosion, while its elastic properties still allow it to vibrate resonantly for sensitive fluid properties measurement, thereby resolving the strength-sensitivity trade-off.
Solution Approach 2:
The patent uses composite material construction by combining the elastic capillary tube with an internal electrical conductor. This composite structure provides both the mechanical strength needed to resist corrosion and particle impact, and the electrical conductivity required for exciting and sensing the resonant vibrations, thereby resolving the vulnerability issue while maintaining measurement capability.
4Reliability
If the wire is electrically insulated to prevent current shorting in conductive fluids, then the wire is protected from electrical damage, but the mechanical circuit becomes complex with materials of differing characteristics
Solution Approach 1:
The patent extracts the electrical conduction function from the elastic structure by placing the conductor inside the capillary tube. This separation allows the elastic tube to be made of corrosion-resistant material without insulating coatings that would cause thermal expansion issues, while the internal conductor provides the necessary electrical functionality for resonance excitation and sensing.
5Measurement precision
If the resonator is exposed to the fluid for direct measurement, then the measurement is accurate, but the sensor cannot operate in high-pressure applications like downhole drilling
Solution Approach 1:
The patent applies this principle by using a thicker elastic capillary tube instead of a thin wire. The capillary tube's greater thickness provides mechanical strength to resist particle impact and corrosion, while its elastic properties still allow it to vibrate resonantly for sensitive fluid properties measurement, thereby resolving the strength-sensitivity trade-off.
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 accurate measurement of fluid properties like density and viscosity in conductive fluids and extreme conditions, reducing mechanical vulnerability and temperature-dependent errors, and maintaining sensor integrity in high-pressure applications.
Implementation Method 1
A current passed through this wire results in a Lorentz force being applied to the wire, in a direction mutually perpendicular to the magnetic field
Implementation Method 2
This continuing transverse oscillation will result in a current being induced in the wire, because it is a conductor moving in a magnetic field
Implementation Method 3
Solid material fills space between the conductor and the elastic tube interior surface, such that force generated by the conductor is directly transmitted to the elastic tube
Data Source
AI summary
A resonator that includes an elastic tube defining an interior surface and a conductor threaded through the elastic tube. Solid material fills space between the conductor and the elastic tube interior surface, such that motion of the conductor is directly transferred to the elastic tube. In a preferred embodiment, the elastic tube is electrically conductive and said solid material insulates said conductor from said elastic tube.