Vibrating Fork Coil-Magnet Layout for Low-Power Resonance
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Solution Overview
Problem
Existing vibrating fork type field devices for determining material properties are complex and costly, particularly due to the use of lead-containing piezoelectric transducers, and there is a need for a simpler and more cost-efficient alternative for high-temperature applications.
Innovation Solution
A field device design that uses a coil arrangement fixed to one rod and a magnet (permanent or electromagnet) on the other rod to induce vibrations, eliminating the need for a three-member magnetic system and allowing for stronger coupling and lower power operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If piezoelectric transducers are used to induce vibrations, then the field device achieves reliable vibration induction, but the device becomes complex and costly due to lead-containing materials
Solution Approach 1:
The patent replaces the mechanical piezoelectric transducer system with an electromagnetic system consisting of a coil arrangement and magnet. This substitution eliminates the need for lead-containing piezoelectric materials while achieving the same vibration induction function through electromagnetic interaction between the coil and magnet.
Solution Approach 2:
The patent extracts and eliminates the complex piezoelectric transducer component from the device. By removing this component and replacing it with simpler electromagnetic elements (coil and magnet), the device complexity is reduced while maintaining the essential vibration induction function.
2Force
If a three-member magnetic system with coil around core is used, then the field device achieves sufficient magnetic coupling, but the manufacturing cost and complexity increase
Solution Approach 1:
The patent segments the magnetic system into two independent components: a coil arrangement fixed to one rod and a magnet fixed to the other rod. This segmentation simplifies the manufacturing process by eliminating the need for specially shaped cores and complex winding operations, while the close proximity of the segmented components maintains sufficient magnetic coupling strength.
Solution Approach 2:
Instead of fixing the coil to a stationary core and moving the magnet (traditional approach), the patent inverts the arrangement by fixing the coil to one moving rod and the magnet to the other moving rod. This inversion simplifies the overall structure and manufacturing while achieving the required magnetic coupling through the relative motion of the two components.
3Power
If standard electromagnetic transducers are used, then the field device achieves vibration induction, but the power consumption increases
Solution Approach 1:
The patent applies preliminary action by pre-fixing the coil arrangement to one rod and the magnet to the other rod in specific positions. This preliminary positioning ensures optimal magnetic coupling from the start, maximizing the efficiency of the electromagnetic interaction and minimizing the power required to induce vibrations at the resonant frequency of the tines.
Solution Approach 2:
The patent optimizes the parameters of the electromagnetic system by carefully selecting the coil geometry, number of turns, and magnet strength to achieve resonant vibration induction. By tuning these parameters to match the natural resonant frequency of the tines, the system achieves maximum vibration induction efficiency with minimum power consumption.
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 results in a simpler, cost-efficient field device with improved determination of medium properties by reducing dynamic deformations and enabling lower power consumption.
Implementation Method 1
the coil arrangement (23) fixed to a first one (21a) of the two rods (21a-b) and a magnet (25) fixed to a second one (21b) of the two rods (21a-b)... induce the desired vibration by passing a time-varying current through a coil of the coil arrangement (23)
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A field device comprising first and second tines; first and second rods coupled to the first and second tines; a coil arrangement fixed to the first rod; a magnet fixed to the second rod, opposite the coil arrangement; excitation circuitry coupled to the coil arrangement and controllable to provide a time-varying current to the coil arrangement, resulting in vibration of the first tine in relation to the second tine; sensing circuitry coupled to the coil arrangement and configured to provide a sensing signal indicative of a change in at least one property of the vibration of the first tine in relation to the second tine; and measurement control circuitry coupled to the excitation circuitry and the sensing circuitry for controlling operation of the excitation circuitry.