Mass Flowmeter Multi-Layer Substrate Impact Resistance
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Solution Overview
Problem
Conventional mass flowmeters and velocimeters with diaphragm structures are prone to damage from impacts and rely on temperature changes detected by sensor resistors, which are influenced by the heat capacity of the diaphragm, limiting their durability and accuracy.
Innovation Solution
A mass flowmeter and velocimeter design featuring a multi-layer substrate with thermoelectric conversion elements and a heat source, where the substrate is formed by pressurizing and heating insulating layers of thermoplastic resin with different conductors, allowing for the detection of temperature changes without a large space, thus enhancing durability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thin diaphragm structure is used to reduce heat capacity influence on sensor resistors, then measurement precision is improved, but the sensor becomes more susceptible to impact damage and reliability deteriorates
Solution Approach 1:
The invention changes the detection principle from resistance-based temperature sensing to thermoelectric voltage-based sensing. By utilizing the Seebeck effect in a multi-layer substrate with different conductors, the system can detect temperature changes through voltage generation rather than resistance change, eliminating the need for a thin diaphragm structure while maintaining measurement precision and improving impact resistance
Solution Approach 2:
The invention employs a multi-layer substrate comprising alternating layers of different conductors and insulating materials. This composite structure enables thermoelectric conversion while providing mechanical strength and impact resistance, replacing the fragile thin diaphragm with a robust layered construction that maintains thermal sensitivity without compromising durability
2Measurement precision
If a space is provided immediately below the diaphragm to reduce thermal influence from the sensor chip, then measurement precision is improved, but device complexity and structural vulnerability increase
Solution Approach 1:
The invention extracts the thermal isolation function from the diaphragm structure itself and relocates it to the heat source design. By positioning the heat source away from the detection region and using insulating layers in the multi-layer substrate, thermal influence is reduced without requiring additional space below the diaphragm, simplifying the overall structure
Solution Approach 2:
The invention transitions from a planar diaphragm structure with vertical spacing to a multi-layer three-dimensional substrate. The thermal isolation is achieved through layered insulating materials distributed throughout the substrate thickness, eliminating the need for a large void space while maintaining thermal performance
3Device complexity
If sensor resistors are used to detect temperature change, then the detection method is simple, but measurement precision is limited by heat capacity influence from the diaphragm
Solution Approach 1:
The invention replaces the electrical resistance-based detection system with a thermoelectric voltage-based system. By utilizing the Seebeck effect where temperature differences directly generate measurable voltage signals in the multi-layer conductor structure, the system achieves higher precision without complex compensation circuits needed for resistance-based sensing
Solution Approach 2:
The invention changes the detection parameter from electrical resistance to thermoelectric voltage. This parameter change enables direct temperature difference measurement through voltage generation, eliminating the indirect measurement through resistance change that is influenced by diaphragm heat capacity, thereby improving precision while maintaining operational simplicity
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 more robust and accurate method for detecting fluid temperature changes and mass flow rates or object velocities by generating electrical outputs based on temperature differences, reducing the risk of damage from impacts and improving sensitivity.
Implementation Method 1
the sensor (10, 20) having a thermoelectric conversion element formed therein... when the fluid having heat released from the heat source is moved along the one face, the thermoelectric conversion element is configured to generate an electrical output corresponding to a temperature difference generated between a first region located on the one face and a second region located at a position different from the first region in the sensor
Implementation Method 2
a heat source (13, 14, 240) configured to release one of heat and cold heat to a fluid present on the one face side
Data Source
AI summary
A mass flowmeter includes a flow sensor having a first sensor part and a second sensor part formed on both sides of a heater part. The flow sensor is formed of a thermoplastic resin, and is configured of a multi-layer substrate including a plurality of stacked insulating layers, and a first conductor and a second conductor and formed on these insulating layers and connected to each other. The multi-layer substrate is formed by pressurizing and heating the plurality of insulating layers for integration. When a fluid having heat released from the heater part is moved along the one face of the flow sensor, the first and the second sensor parts and generate electromotive forces in the level corresponding to temperature differences generated between the one face and the other face in the first and the second sensor parts. The flow sensor has a structure manufactured by pressurizing and heating the plurality of insulating layers for integration. The structure has no large space unlike a structure having a space immediately below a diaphragm. Thus, the flow sensor is less breakable than a sensor having a diaphragm structure is.