Mass Flow Meter Temperature Sensor With Grid Flow Equalization
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Solution Overview
Problem
Conventional mass flow controllers struggle to accurately measure and control gas flow rates due to temperature variations, as temperature sensors are often integrated with large heat capacity components or within flow channels, leading to inaccurate temperature readings and deviations from target flow rates.
Innovation Solution
A temperature sensor for mass flow meters featuring a flow channel with a temperature measuring point and a temperature uniformalizing means comprising a grid of periodically arranged partitions extending in arbitrary directions perpendicular to the fluid flow, which divides the flow into sub-channels, promoting heat transfer by convection and conduction to achieve uniform temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature sensor is integrated with a large heat capacity component or disposed within a flow channel, then the temperature measurement is stable, but the temperature reading becomes inaccurate due to heat exchange between the sensor and the component
Solution Approach 1:
The flow channel is segmented into multiple sub-flow channels by the grid structure, which divides the fluid flow into multiple paths. This segmentation increases the surface area for heat exchange and promotes more uniform temperature distribution across the flow channel, allowing the temperature sensor to measure a more representative average temperature rather than a localized temperature that may be skewed by heat exchange with the channel walls.
Solution Approach 2:
The grid structure acts as an intermediary element between the temperature sensor and the fluid flow. It mediates the temperature distribution by creating multiple flow paths that enhance heat exchange, thereby transforming the temperature profile from non-uniform to more uniform, which improves the accuracy of the temperature sensor reading.
2Temperature
If the temperature of the flow channel differs from the temperature of the gas, then heat exchange occurs between the flow channel wall and the gas, but the gas temperature changes easily due to its small heat capacity
Solution Approach 1:
By dividing the flow channel into multiple sub-flow channels using the grid, the patent increases the total surface area available for heat exchange between the flow channel walls and the gas. This enhanced surface area allows for more effective and uniform heat distribution across the entire gas flow, reducing temperature variations and improving temperature stability despite the gas's small heat capacity.
Solution Approach 2:
The grid structure creates periodic flow patterns as the gas moves through the multiple sub-channels, promoting continuous mixing and heat exchange. This periodic action ensures that temperature differences between the flow channel walls and the gas are continuously equalized, maintaining stable gas temperature throughout the flow channel.
3Device complexity
If a temperature sensor is disposed inside or on a surface of a main body block, then the structure is simplified, but the temperature measurement does not reflect the actual fluid temperature due to heat capacity effects
Solution Approach 1:
The grid structure segments the fluid flow into multiple paths, creating a more uniform temperature distribution that allows a simple temperature sensor to measure a representative average temperature. This maintains structural simplicity while improving measurement accuracy, as the sensor now measures a more homogeneous temperature field rather than a localized temperature influenced by heat exchange with the main body block.
Solution Approach 2:
The grid introduces local variations in flow paths and heat exchange areas, creating zones of enhanced heat transfer throughout the flow channel. This local quality improvement ensures that the temperature at any point, including where the simple temperature sensor is located, more accurately reflects the overall fluid temperature.
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 configuration allows for accurate measurement of the overall fluid temperature, enabling precise correction and control of flow rates, thereby stabilizing gas supply despite temperature changes.
Implementation Method 1
promoting heat transfer by convection and conduction to achieve uniform temperature distribution
Implementation Method 2
promoting heat transfer by convection and conduction to achieve uniform temperature distribution
Data Source
AI summary
A temperature sensor used for a mass flow meter is constituted by a flow channel through which a fluid flows, a temperature measuring means which has a temperature measuring point in a central part of a cross section of the flow channel, and a temperature uniformalizing means disposed on an upstream side from the temperature measuring point in the flow channel. The temperature uniformalizing means comprises a grid disposed so as to continuously extend in arbitrary directions perpendicular to a direction in which a fluid flows, and sub flow channels divided by said grid. Thereby, a temperature sensor which can acquire a measured temperature value representing temperature of the fluid even in a case where temperature of the fluid supplied to a mass flow meter from the outside altered can be realized.