Acoustic Flow Sensor for Infusion Pump Feedback Control
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Solution Overview
Problem
Current infusion systems operate in an open loop configuration without feedback, leading to inaccuracies in medication delivery due to component degradation over time, and require tight manufacturing tolerances, increasing costs.
Innovation Solution
An infusion system utilizing high-frequency acoustic sensors in a closed loop configuration to measure and control the volumetric flow rate of an infusion pump, with upstream and downstream sensors detecting phase delays to determine and adjust the flow rate accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If open loop configuration is used without feedback, then device complexity is reduced, but measurement precision of medication delivery deteriorates due to component degradation
Solution Approach 1:
The patent implements a closed-loop feedback system using acoustic sensors positioned upstream and downstream of the infusion pump to continuously monitor fluid flow velocity. The system measures the time delay of acoustic signals traveling through the fluid to calculate actual flow rate, compares it to the prescribed flow rate, and automatically adjusts pump parameters to maintain accurate medication delivery despite component degradation over time.
2Measurement precision
If tight manufacturing tolerances are applied to maintain accuracy, then measurement precision is improved, but manufacturing cost increases significantly
Solution Approach 1:
The system employs self-adjusting feedback control where the acoustic flow measurement system automatically compensates for pump degradation and flow variations. The controller continuously monitors actual flow rate and adjusts pump operating parameters without requiring manual calibration or precision manufacturing, allowing standard tolerance components to achieve accurate delivery through active compensation.
3Measurement precision
If acoustic sensors are added for continuous flow measurement, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system uses acoustic waves as an intermediary to measure fluid flow velocity non-invasively. Acoustic sensors transmit sound waves through the infusion fluid and measure the time delay of signal propagation to calculate flow rate. This indirect measurement method avoids direct contact with the fluid stream, simplifying sensor placement and reducing mechanical complexity compared to direct flow measurement approaches.
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 achieves precise and continuous measurement and control of infusion fluid flow, reducing inaccuracies and manufacturing costs while accounting for component degradation in real-time.
Implementation Method 1
The programming code is configured to determine the volumetric flow rate of the infusion fluid along the flow path based on a first phase delay of the upstream acoustic signal between the upstream acoustic sensor and the downstream acoustic sensor, and/or on a second phase delay of the downstream acoustic signal between the downstream acoustic sensor and the upstream acoustic sensor.
Data Source
AI summary
An infusion system determines a volumetric flow rate of infusion fluid delivered by an infusion pump along a flow path based on: an upstream acoustic signal emitted by at least one upstream acoustic sensor and detected by at least one downstream acoustic sensor; a downstream acoustic signal emitted by the downstream acoustic signal and detected by the upstream acoustic sensor; and a phase delay between the upstream acoustic signal and the downstream acoustic signal either upstream or downstream. The infusion system automatically adjusts the infusion pump based on the determined volumetric flow rate to achieve a desired volumetric flow rate of the infusion fluid along the flow path.