Integrally Molded Magnetic Flowmeter with Polymer Wafer
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Solution Overview
Problem
Magnetic flowmeters face challenges in manufacturing due to the difficulty in arranging and positioning electrodes and magnetic coils, which require additional metal components leading to magnetic eddy current losses and complex bonding processes, especially in high-pressure applications where rigid flow tubes are necessary.
Innovation Solution
A magnetic flowmeter design featuring a molded polymer 'wafer' style flow tube with integrated coils and electrodes, potentially reinforced with a metal backup ring, simplifies manufacturing by eliminating the need for external metal components and reducing magnetic eddy current losses, allowing for easier assembly and pressure containment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid metal flow tube is used to provide strength in high pressure applications, then pressure containment capability is improved, but device complexity increases due to additional metal components and complex bonding processes
Solution Approach 1:
The patent combines the flow tube, coils, and electrodes into a single integrally molded polymer structure. This merging eliminates the need for separate metal components and complex bonding processes, while still achieving the required pressure containment capability through the molded polymer construction.
Solution Approach 2:
The patent uses a composite structure where a polymer flow tube is molded with embedded coils and electrodes. This composite approach allows the non-conductive polymer to eliminate eddy currents while maintaining structural integrity for pressure containment, replacing traditional metal components.
2Strength
If additional metal components are added to provide structural strength, then pressure containment is improved, but magnetic eddy current losses increase
Solution Approach 1:
The patent employs a composite material solution by using a non-conductive polymer as the flow tube material. This polymer is molded to include embedded coils and electrodes, creating a structurally sound assembly that eliminates magnetic eddy current losses inherent in traditional metal flow tubes while maintaining the necessary structural strength.
3Ease of manufacture
If traditional manufacturing processes with separate components are used, then ease of manufacture is reduced, but manufacturing precision can be maintained
Solution Approach 1:
The patent merges the flow tube, coils, and electrodes into a single integrally molded component. This eliminates the need for separate assembly steps and complex positioning operations, greatly simplifying manufacturing while ensuring precise relative positioning of all components through the molding process itself.
Solution Approach 2:
The coils and electrodes are pre-positioned within the mold cavity before the polymer is injected. This preliminary action ensures that the components are accurately positioned during the molding process, eliminating the need for subsequent positioning and bonding operations while maintaining manufacturing precision.
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 simplifies the manufacturing process, reduces magnetic eddy current losses, and provides effective pressure containment, while enabling flexible coil and electrode arrangement, enhancing the overall efficiency and accuracy of flow measurement.
Implementation Method 1
In accordance with Faraday's law of electromagnetic induction, when the conductive process fluid moves in a perpendicular direction through a magnetic field, a voltage is induced in the fluid that is proportional to the velocity of the process fluid and the strength of the applied magnetic field. The magnetic field can be created by applying a current to a coil made out of a wire that has been bent into multiple, closely-spaced loops.
Implementation Method 2
Additional metal components, such as the metal flow tube, can result it magnetic eddy current losses between the magnetic coils and the process fluid.
Data Source
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AI summary
A magnetic flowmeter (102) for measuring flow rate of a process fluid, includes a magnetic coil (222) arranged to apply a magnetic field to the process fluid. A pair of electrodes (224) are electronically coupled to the process fluid and arranged to sense a voltage induced in the process fluid related to the applied magnetic field and the flow rate of the process fluid. A molded flow tube (108) of a non-conductive material is arranged to receive a flow of the process fluid. The flow tube (108) is molded around the magnetic coil and the pair of electrodes and is configured to support the magnetic coil and the pair of electrodes (224). Flow meter circuitry (240) is configured to apply a current to the magnetic coil (222) and receive the resultant voltage sensed by the pair of electrodes (224).