Flow Sensor with Pressure and Temperature Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional respirators face challenges in accurately measuring and delivering precise flow rates of various gases and gas mixtures, particularly for neonatal patients, due to the susceptibility of small lungs to overinflation and the unavailability of specific gas mixtures.
Innovation Solution
A flow sensor system comprising a flow restriction, upstream and downstream pressure sensors, a temperature sensor, and a processor that calculates a compensated flow rate based on measured pressures and temperature, ensuring accurate measurement of gas flow rates across a range of temperatures and compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pressure-based flow measurement is used, then the device structure is simple, but measurement precision deteriorates due to temperature and gas composition variations
Solution Approach 1:
The patent combines multiple sensing functions (pressure measurement, temperature measurement, and gas composition identification) into a single integrated flow sensor assembly. The pressure sensors, temperature sensor, and processor are merged into one unit that collectively provides compensated flow rate measurement, resolving the contradiction by achieving high precision through functional integration rather than separate measurement systems.
Solution Approach 2:
The patent applies parameter changes by measuring multiple physical parameters (pressure, temperature) and using gas composition identification to dynamically adjust flow rate calculations. The processor uses these varying parameters to compute compensated flow rates that account for temperature and composition effects, thereby maintaining measurement precision across different operating conditions without requiring complex hardware for each individual compensation.
2Measurement precision
If temperature compensation is added to pressure-based flow measurement, then measurement precision improves, but device complexity increases
Solution Approach 1:
The temperature sensor is integrated into the same sensor assembly as the pressure sensors, with all components mounted together and processed by a single processor. This merging approach allows temperature compensation to be added without proportionally increasing overall device complexity, as the temperature sensing function is incorporated into the existing structural framework rather than requiring a separate independent system.
3Measurement precision
If gas composition identification is implemented, then measurement precision improves for different gases, but device complexity increases
Solution Approach 1:
The processor is designed with multi-functionality, serving both to identify gas composition based on pressure measurement characteristics and to calculate compensated flow rates. This universal processing approach allows gas composition identification without requiring separate dedicated hardware for composition analysis, thereby improving measurement precision for different gases while minimizing the increase in device complexity through software-based identification.
4Measurement precision
If multiple sensors are integrated in a small space, then measurement precision improves through compensation, but manufacturing precision requirements increase
Solution Approach 1:
The sensor assembly merges pressure sensors and temperature sensor into a compact integrated unit with common mounting structures and shared processing electronics. This merging design allows the multiple sensors to be positioned and calibrated together as a single assembly, reducing the cumulative effect of individual positioning errors and simplifying manufacturing precision requirements while still achieving accurate compensated measurements through the integrated sensing approach.
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 system provides increased accuracy in gas flow measurement, compensating for gas composition and temperature, thereby improving patient safety by ensuring precise gas delivery.
Implementation Method 1
a flow restriction disposed within a passage coupled between the input flow channel and the output flow channel such that the gas passing through the passage must pass through the flow restriction
Implementation Method 2
an upstream pressure sensor coupled to the passage at a point upstream of the flow restriction and configured to measure and provide an upstream pressure of the gas within the passage, a downstream pressure sensor coupled to the passage at a point downstream of the flow restriction and configured to measure and provide a downstream pressure of the gas within the passage
Implementation Method 3
a temperature sensor coupled to the passage and configured to measure and provide a temperature of the gas within the passage
Implementation Method 4
a flow sensor processor coupled to the upstream and downstream pressure sensors and the temperature sensor and configured to accept measurements therefrom and calculate a compensated flow rate based at least in part on the measured pressures and temperature
Data Source
AI summary
A flow sensor comprises a flow restriction disposed within a passage such that a fluid passing through the passage must pass through the flow restriction. The flow sensor also has an upstream pressure sensor coupled to the passage at a point upstream of the flow restriction and configured to measure and provide an upstream pressure of the fluid within the passage, a downstream pressure sensor coupled to the passage at a point downstream of the flow restriction and configured to measure and provide a downstream pressure of the fluid within the passage, and a temperature sensor coupled to the passage and configured to measure and provide a temperature of the fluid within the passage. The flow sensor also includes a flow sensor processor coupled to the upstream and downstream pressure sensors and the temperature sensor and configured to accept measurements therefrom and calculate a compensated flow rate based at least in part on the measured pressures and temperature.