MEMS Gas Meter Auto-Compensation for Composition Variations
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Solution Overview
Problem
Current utility gas meters using MEMS mass flow sensing technology are sensitive to gas compositions, leading to varying thermal values and tariff disputes, as they do not accurately compensate for temperature and pressure variations, which are not universally standardized, affecting fairness in custody transfer and revenue for both consumers and gas companies.
Innovation Solution
A new electronic utility gas meter utilizing MEMS mass flow sensing technology with integrated thermistors and gas thermal property sensors, capable of in situ measurement and auto-compensation for gas thermal values, ensuring tariff consistency by eliminating the impact of gas composition variations, and enabling remote data transmission and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MEMS thermal calorimetric sensing technology is used for gas metering, then the measurement is independent of gas temperature and pressure, but the measurement is sensitive to gas compositions leading to varying thermal values and tariff disputes
Solution Approach 1:
The patent segments the sensing system into multiple independent sensors: a thermal calorimetric sensor for mass flow measurement and a separate gas composition sensor (such as a semiconductor sensor or catalytic sensor) for detecting gas thermal properties. This segmentation allows each sensor to perform its specialized function without interference, resolving the contradiction between temperature/pressure independence and composition sensitivity.
Solution Approach 2:
The patent introduces a microprocessor or digital signal processor as an intermediary that receives signals from both the thermal calorimetric sensor and the gas composition sensor. This intermediary processes the data from both sensors and applies compensation algorithms to calculate the corrected mass flow rate, thereby eliminating the harmful effect of gas composition variations on the thermal value measurement.
2Device complexity
If mechanical gas meters are calibrated against arbitrary reference temperature and pressure, then the metering system is simple, but the tariff fairness is compromised due to environmental variations
Solution Approach 1:
The patent replaces the traditional mechanical calibration system with an electronic sensing and processing system. Instead of relying on mechanical components calibrated to arbitrary reference conditions, the system uses electronic sensors to actively measure the actual gas temperature, pressure, and composition, then uses digital processing to compensate for deviations from standard conditions. This substitution maintains simplicity while dramatically improving measurement precision and tariff fairness.
Solution Approach 2:
The patent dynamically adjusts the measurement parameters by incorporating real-time sensing of temperature, pressure, and gas composition. The system changes the operating parameters of the sensors and the processing algorithms based on the actual environmental conditions, allowing the meter to adapt to varying conditions and maintain accurate, fair measurements regardless of the ambient environment.
3Reliability
If excessive protection is applied to the sensing element, then the sensing element is protected, but the pressure drop increases significantly limiting applications
Solution Approach 1:
The patent employs thin-film technology in the MEMS sensing elements, where the sensing membrane is fabricated as a thin film structure. This thin-film design provides adequate mechanical protection and structural integrity for the sensing element while maintaining high permeability to gas flow, thereby minimizing pressure drop. The flexible thin-film structure can withstand operational stresses without requiring excessive protection that would impede gas flow.
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 accurate, temperature and pressure-independent gas metering, ensuring consistent tariffs and reducing revenue losses for gas companies, while allowing for remote data management and minimizing disputes through auto-compensation of gas thermal properties, thus enhancing the deployment of utility gas meters across different regions.
Implementation Method 1
All of the current MEMS sensing technology adopted in the utility gas meters is based on the thermal calorimetric sensing principle
Implementation Method 2
the said MEMS gas property sensor is to sense the thermal conductivity and thermal capacitance of the gas properties
Implementation Method 3
The gas meter will utilize the MEMS mass flow sensor for metering the mass flowrate of the utility gas for the desired temperature and pressure independent tariff. The MEMS mass flow sensor will have integrated thermistors
Data Source
AI summary
An electronic utility gas meter using MEMS thermal mass flow sensor to meter gas custody transfer and MEMS gas thermal property sensor to compensate the metering values due to gas composition variations is disclosed in the present invention. The meter is designed to have a MEMS mass flow sensor to meter the city utility gas consumption independent of environmental temperature and pressure while a MEMS gas thermal property or dual gas thermal property sensors to compensate the tariff due to the gas composition variations for compliance with the current regulation requirements of tariff and remove the major concerns for the wide deployment of the thermal mass MEMS utility gas meters.