Respirator Flow Meter Pneumatic Bridge Calibration
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Solution Overview
Problem
Existing systems with electrically controlled sources of gas flow or pneumatic power in respirators lack continuity and long-term stability in measuring breathing gas flow during inhalation and exhalation phases, and do not effectively minimize expiratory path resistance.
Innovation Solution
A system with an electrically controlled source of gas flow or pneumatic power, featuring a calibrated flow meter connected diagonally in a pneumatic bridge, allowing for auto-calibration in each breathing cycle and compensation for expiratory path resistance using a multi-segment diaphragm pump and microcontroller control block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow meter is used in existing respirator systems, then gas flow measurement is enabled, but measurement continuity and long-term stability are insufficient
Solution Approach 1:
The system performs preliminary calibration of the flow meter using a calibration source of gas flow before actual measurement begins. The microcontroller control block executes a calibration routine that establishes baseline measurements, ensuring subsequent measurements start from a known stable reference point. This preliminary action resolves the contradiction by preparing the measurement system in advance to ensure both precision and continuity.
Solution Approach 2:
The microcontroller control block continuously monitors flow meter output and compares it against expected values during both inhalation and exhalation phases. When deviations are detected, the system automatically adjusts or re-calibrates the flow meter, creating a closed-loop feedback mechanism. This feedback ensures long-term measurement stability and continuity, resolving the reliability issue while maintaining precision.
2Measurement precision
If pressure measurement point is placed in the expiratory path, then expiratory flow measurement is enabled, but resistance of the expiratory path is increased
Solution Approach 1:
The system introduces a calibration source of gas flow as an intermediary that provides a known reference flow through the expiratory path during calibration phases. This intermediary allows the system to characterize and compensate for the expiratory path resistance without permanently obstructing the path during patient breathing. The calibration source enables measurement capability while minimizing harmful resistance effects during actual use.
Solution Approach 2:
The microcontroller control block dynamically adjusts system parameters based on calibration data, including compensation for expiratory path resistance. By changing the measurement and control parameters to account for the known resistance characteristics, the system maintains accurate expiratory flow measurement while minimizing the impact of resistance on patient breathing. The parameters are adjusted in real-time to optimize both measurement precision and minimize harmful effects.
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 ensures stable and continuous measurement of breathing gas flow in both phases, minimizes expiratory path resistance, and provides ongoing assessment of flow meter performance, leading to improved functionality and parameter stability of the respirator.
Implementation Method 1
a flow meter located in the inspiratory section, a microcontroller control block connected to the flow meter, comprising a flow meter calibration module
Implementation Method 2
the flow meter is connected, on one side, between a first check valve of the inspiratory section and an inspiratory tube and its downstream second check valve of the inspiratory section and, on the other side, is connected between a third check valve of an expiratory section
Implementation Method 3
the calibration source of the gas flow is a diaphragm pump
Implementation Method 4
there is a diverter valve upstream of the first check valve of the inspiratory section, a second output of which is connected to a second input of an ejector, and a first input of the ejector is connected to the output of the shut-off valve
Data Source
AI summary
The object of the invention is a system with an electrically controlled source of gas flow or pneumatic power, comprising a block of calibration source of gas flow or pneumatic power connected pneumatically to the inspiratory section, a flow meter located in the inspiratory section, a microcontroller control block connected to the flow meter, comprising a flow meter calibration module, characterised in that the flow meter (131) is connected, on one side, between a first check valve (133A) of the inspiratory section and an inspiratory tube (134A) and its downstream second check valve (133B) of the inspiratory section and, on the other side, is connected between a third check valve (133C) of an expiratory section, connected to its downstream expiratory tube, (134B) and a shut-off valve (ZP), so that the flow meter (131) is located on a diagonal of a pneumatic bridge thus formed, and the calibration flow qi and the expiratory flow qe flow through the flow meter (131) alternately in the inhalation and exhalation phases in the same direction.