Polymeric Coriolis Flowmeter Manifold Design
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Solution Overview
Problem
Traditional Coriolis flowmeters using metal alloy flow tubes face issues with adhesive degradation, thermal expansion, and contamination risks, particularly in high-purity applications, when attempting to use plastic flow tubes, leading to unstable boundary conditions and inaccurate measurements.
Innovation Solution
A Coriolis mass flowmeter is manufactured from polymeric materials with a dynamically responsive manifold and flow-sensitive elements, eliminating mechanical joints and adhesives, and using curvilinear tubing with thin walls to prevent contamination and ensure a stable boundary condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive is used to attach polymer tube to metal base, then assembly is easier, but joint stability deteriorates due to vibration and thermal expansion
Solution Approach 1:
The patent removes the adhesive layer from the assembly, eliminating the weak interface between dissimilar materials. The polymer tube is directly attached to the metal base without any intermediate adhesive, thereby eliminating the source of joint degradation under vibration and thermal stress.
Solution Approach 2:
The patent employs a composite structure where a polymer tube with integrated mounting features (such as integral feet or flanges) is directly coupled to the metal base. This composite design eliminates the need for adhesives by integrating the attachment functionality into the tube structure itself, creating a more reliable vibration-resistant joint.
2Adaptability or versatility
If different materials (polymer tube, adhesive, metal base) are used, then assembly flexibility is improved, but thermal expansion compatibility deteriorates
Solution Approach 1:
The patent applies local quality by providing thermal expansion compensation specifically at the interface between dissimilar materials. The flexible membrane or bellows structure is localized at the connection point, allowing differential thermal expansion between the polymer tube and metal base while maintaining overall structural integrity and stable boundary conditions for the diaphragm.
Solution Approach 2:
The patent explicitly addresses thermal expansion by incorporating flexible membranes or bellows structures that can accommodate the differential thermal expansion between polymer and metal components. These elements expand and contract with temperature changes, preventing stress buildup and maintaining stable boundary conditions at the diaphragm interface.
3Strength
If etching process is used on PFA tubing, then adhesive bonding is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent removes the etching process from the manufacturing sequence by eliminating the need for adhesive bonding entirely. The polymer tube is directly attached to the metal base through mechanical means (integral feet or flanges), thereby eliminating the requirement for surface modification and simplifying the fabrication process.
Solution Approach 2:
The patent merges the tube structure with the mounting features by creating integral feet or flanges as part of the tube itself. This integration eliminates the need for separate attachment components and the complex etching process, reducing manufacturing steps while maintaining joint strength.
4Ease of manufacture
If adhesive joint is used, then assembly is simpler, but long-term integrity under vibration deteriorates
Solution Approach 1:
The patent extracts the adhesive layer from the assembly, eliminating the component that degrades under vibration. The direct mechanical attachment through integral feet or flanges provides a vibration-resistant joint that maintains integrity over time without relying on adhesive bonds.
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 approach provides an unyielding, fixed boundary condition, enhances measurement sensitivity, and prevents metallic contamination, making the flowmeter suitable for high-purity applications by avoiding the limitations of traditional methods.
Implementation Method 1
Traditional Coriolis flowmeters employ various configurations of one or two tubes (through which fluid flows) that are oscillated in a controlled manner allowing measurement of Coriolis induced deflections (or the effects of such deflections on the tube(s)) as an indication of fluid mass flow rate flowing through the sensor.
Data Source
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AI summary
A method of manufacturing a Coriolis mass flowmeter from a polymeric material is described, in which a dynamically responsive manifold is fabricated from the same material as the flow sensor's flow-sensitive elements. The flowmeter is free of mechanical joints and adhesives. The manifold and flow-sensitive elements therefore do not slip or change their location relative one another, nor are they subject to differing degrees of thermal expansion that would otherwise undermine integrity, reliability, and/or accuracy of the boundary condition at the ends of the vibrating flow-sensitive elements.