Polymer Coriolis Mass Flow Sensor Casting for Thin-Wall Tubes
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Solution Overview
Problem
Conventional Coriolis mass flow sensors face issues such as cracking during injection molding, deformation due to high pressure and heat, high cost and weight of metal enclosures, and ineffective chemical sterilization, which are not suitable for single-use applications.
Innovation Solution
A polymer-based Coriolis mass flow sensor with a support cast around the flow tube using a casting process, featuring a thin-walled flow tube, plastic enclosure, and memory chip for calibration data, allowing Gamma irradiation sterilization and eliminating the need for in-situ calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If injection molding is used to manufacture the support, then the support can be mass-produced efficiently, but the support may crack during cooling and the flow tube may deform due to high pressure and heat
Solution Approach 1:
The patent changes the manufacturing parameters from high pressure and high temperature injection molding to low pressure and low temperature casting. The casting process uses liquid resin that cures at temperatures below 120°C and atmospheric or low pressure, eliminating the thermal and mechanical stresses that cause flow tube deformation while still enabling mass production of supports with good dimensional accuracy.
2Strength
If metal enclosures are used for Coriolis mass flow sensors, then structural strength and position stability are improved, but cost and weight increase significantly
Solution Approach 1:
The patent changes the material parameter from metal to polymer, creating a polymer-based Coriolis mass flow sensor. The polymer materials provide sufficient structural strength for the application while reducing weight by a significant margin. The design compensates for the lower strength-to-weight ratio of polymers through optimized geometry and support structures.
Solution Approach 2:
The patent employs composite material construction, combining polymer flow tubes with polymer supports and polymer enclosures. This all-polymer composite structure achieves the desired balance between strength and weight, eliminating the need for heavy metal enclosures while maintaining structural integrity through the composite nature of the assembled components.
3Reliability
If chemical sterilization is used for metal-enclosed flow sensors, then sterilization can be achieved, but the process is challenging and may not be effective
Solution Approach 1:
The patent changes the material parameter from metal to polymer, which fundamentally alters the sterilization approach. Polymer materials are inherently more compatible with Gamma irradiation sterilization than metal enclosures with chemical sterilization processes. The all-polymer construction allows for effective and simple Gamma sterilization without the complexity and effectiveness issues of chemical sterilization.
4Quantity of substance
If thin-walled flow tubes are used, then material usage is reduced and cost decreases, but the tubes deform during injection molding due to high pressure
Solution Approach 1:
The patent changes the manufacturing process parameters from high pressure injection molding to low pressure casting. This parameter change enables the successful production of thin-walled flow tubes without deformation, as the casting process applies minimal pressure that does not compromise the structural integrity of thin walls while still achieving complete mold filling and proper curing.
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
The solution provides a cost-effective, lightweight, and sterile Coriolis mass flow sensor suitable for single-use applications with high accuracy and reduced deformation, avoiding contamination and calibration challenges.
Implementation Method 1
The liquid resin is cured and solidified in the support cavity to form the support around the tubular legs of the flow tube
Implementation Method 2
A Coriolis mass flow sensor measures a mass flow rate of a fluid flowing through a tube based on Coriolis principles
Implementation Method 3
allowing Gamma irradiation sterilization
Data Source
AI summary
A flow sensor includes a flow tube in a form of a tube and a support cast around the flow tube. The support clamps the flow tube and the flow tube extends through the support. The flow sensor is formed by placing the flow tube in a tube cavity of a casting mold and pouring or injecting a liquid resin into a support cavity of the casting mold. The support is formed around the flow tube from solidifying the liquid resin in the support cavity of the casting mold. A temperature of the casting mold during formation of the support does not exceed a threshold temperature to avoid deformation of the flow tube. The flow sensor can also include at least one memory chip that stores calibration information associated with the flow sensor and connectors that allows a controller to read the calibration information from the memory chip.