Thermal Mass Flowmeter Sleeve with Central Axis Heater
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Solution Overview
Problem
Existing thermal-dispersion type flowmeters face inaccuracies due to insufficient thermal isolation between sensors and potential misalignment of the heater relative to the flow field during installation, leading to errors in flow rate and heat flux measurements.
Innovation Solution
A thermal-dispersion type thermal mass flowmeter design featuring a sleeve with a measuring module containing a bracket with perpendicular plates, a heater, and temperature sensors, where the second sensor and heater are on a central axis, allowing for rotational installation and maintaining a stable position within the flow field, and elastic arms for secure fixation, ensuring accurate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two temperature sensors are placed close together on a circuit board, then the device complexity is reduced, but the thermal isolation between sensors is insufficient leading to measurement errors
Solution Approach 1:
The patent introduces a thermal isolation structure (insulating material or air gap) as an intermediary between the first and second temperature sensors. This mediator prevents direct thermal conduction between sensors while allowing each sensor to measure the temperature of the fluid at its respective position, thus maintaining measurement precision without increasing device complexity
Solution Approach 2:
The patent replaces direct thermal contact (mechanical thermal conduction) between sensors with thermal isolation, substituting the thermal field interaction with an insulated boundary. This allows sensors to be placed close together mechanically while maintaining thermal independence, resolving the contradiction between compact structure and measurement accuracy
2Ease of operation
If the sensing probe is installed without strict orientation requirements, then the ease of operation is improved, but the position of the heater relative to the flow field changes causing measurement inaccuracies
Solution Approach 1:
The patent employs asymmetric design in the sensing probe structure, where the heater and temperature sensors are positioned at specific asymmetric locations relative to the probe axis. This asymmetric configuration creates inherent directional sensitivity that compensates for installation angle variations, allowing the device to maintain measurement accuracy regardless of installation orientation while improving ease of operation
Solution Approach 2:
The patent designs the sensing probe with universal installation capability, making it function effectively in multiple orientations. The heater and sensor arrangement is optimized to provide accurate measurements whether the probe is installed horizontally, vertically, or at angles, eliminating the need for strict orientation requirements during installation
3Device complexity
If a by-pass pipeline configuration is used, then the device complexity is reduced, but the measurement precision of the main pipeline flow rate is compromised
Solution Approach 1:
The patent uses a by-pass pipeline configuration where a smaller measurement section is created as a copy or representation of the main pipeline flow. Temperature sensors and heater are placed in this by-pass section, which replicates the thermal characteristics of the main flow, allowing indirect measurement of main pipeline parameters with reduced device complexity while maintaining acceptable measurement precision
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 design prevents measurement inaccuracies caused by installation deviations, enabling convenient and accurate installation and operation of the flowmeter.
Implementation Method 1
one is heated so that a difference between the temperature measured by the two temperature sensors exists
Implementation Method 2
thermal-dispersion type flowmeter is a precise and reliable flow measuring device operating via thermal convection of fluid
Implementation Method 3
the first temperature sensor is thermally connected to an internal surface of the sleeve
Data Source
AI summary
This disclosure provides a thermal-dispersion type thermal mass flowmeter having a sleeve and a measuring module. Two ends of the sleeve are respectively a fixed end and a measuring end. The measuring module is accommodated in the sleeve. The measuring module has a bracket. A heater, a first temperature sensor, and a second temperature sensor are arranged on the bracket. The first temperature sensor is thermally connected to an internal surface of the sleeve, the second temperature sensor and the heater are thermally connected to the measuring end, and the second temperature sensor and the heater are arranged on the central axis of the sleeve.