Mass Flow Meter Organic Covering Layer High Temperature
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Solution Overview
Problem
Conventional flow sensors face issues with condensable gases condensing inside the sensor tube, leading to inaccurate measurements, and the covering layer degrading at high temperatures, causing electrical insulation and thermal conduction failures.
Innovation Solution
A flow sensor design with a thicker first covering layer (10 micrometers or more) and a second covering layer with finely dispersed inorganic material, along with an annealing treatment in an inert gas atmosphere at 300°C or more for 10 hours or more, to prevent degradation and maintain insulation and thermal conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flow sensor uses a conventional covering layer thickness, then the manufacturing cost is reduced and the structure is simple, but the covering layer degrades at high temperatures causing electrical insulation failure
Solution Approach 1:
The covering layer is divided into multiple functional layers: a base covering layer providing electrical insulation, and additional covering layers containing inorganic materials for thermal stability. Each layer performs a specific function, allowing the system to maintain insulation reliability while managing thermal degradation through layered protection.
Solution Approach 2:
The covering layer uses composite materials combining organic insulating materials with inorganic materials (such as silica or alumina). This composite structure provides both the electrical insulation properties of organic materials and the high-temperature stability of inorganic materials, resolving the contradiction between insulation reliability and thermal resistance.
2Measurement precision
If the flow sensor operates at high temperatures to prevent condensable gas condensation, then measurement accuracy is maintained, but the covering layer degrades causing insulation failure
Solution Approach 1:
The covering layer incorporates inorganic materials such as silica or alumina that are chemically inert and stable at high temperatures. These materials create a protective environment that prevents oxidative degradation of the organic insulating components, allowing the sensor to operate at elevated temperatures without covering layer failure.
Solution Approach 2:
The invention changes the thermal and chemical parameters of the covering layer by incorporating high-melting-point inorganic materials. This allows the covering layer to withstand the high operating temperatures required for condensable gas measurement while maintaining its structural integrity and insulating properties.
3Temperature
If a thicker first covering layer is used to improve thermal resistance, then high temperature operation is enabled, but the manufacturing process becomes more complex
Solution Approach 1:
The base covering layer is formed first on the sensor wire before winding around the sensor tube. This preliminary formation ensures proper adhesion and thickness control, simplifying subsequent manufacturing steps. The inorganic materials are then incorporated into this pre-formed layer, making the thick covering layer easier to manufacture.
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 extends the lifespan of the flow sensor at high temperatures, preventing condensation and maintaining accurate measurements, reducing costs and improving semiconductor manufacturing process efficiency.
Implementation Method 1
an annealing treatment in an inert gas atmosphere at 300°C or more for 10 hours or more
Implementation Method 2
maintaining accurate measurements, reducing costs and improving semiconductor manufacturing process efficiency
Data Source
AI summary
Mass flow sensors, mass flow meters, and methods of making the same are disclosed. A flow sensor may include one sensor tube, a pair of sensor wires wound around the sensor tube, and a covering layer disposed in the surroundings of the sensor tube and the sensor wires. The covering layer includes a first covering layer disposed in contact with the surface of the sensor tube, a second covering layer disposed in contact with the surface of the sensor wires, a third covering layer disposed in a space surrounded by the first covering layer and the second covering layer, and a fourth covering layer disposed so as to cover the whole of the sensor wires wound around the sensor tube. In variations, the covering layer includes one or two organic materials chosen from polyamide-imide and polyimide, and the film thickness of the first covering layer is 10 micrometers or more.