Acoustic Air Bubble Detection in IV Infusion Pump Cassette
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Solution Overview
Problem
Current IV infusion pump systems face challenges in accurately detecting air bubbles due to misloading, tubing material variations, and manufacturing inconsistencies, leading to false alarms and suboptimal sensing capacity.
Innovation Solution
A disposable pump cassette body with an upstanding flow director vane, elastomeric member, and acoustic sensor system, featuring a tapered U-shaped fluid flow path and secure fitment design to enhance air bubble detection and reduce false alarms by maintaining proper acoustic coupling and fluid flow optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the IV tube is threaded into the sensor pocket to ensure coupling, then air bubble detection capability is improved, but misloading occurs when insufficient force is applied causing false alarms
Solution Approach 1:
The sensor is pre-integrated into the pump cassette body during manufacturing, eliminating the need for separate threading operations. The IV tube is pre-aligned with the sensor opening and simply inserted, ensuring proper coupling is achieved before use without requiring manual threading adjustments
Solution Approach 2:
The sensor is merged with the pump cassette body into a single integrated unit. The sensor opening is formed directly in the cassette body, combining the sensor mounting structure with the pump housing to eliminate separate coupling components and reduce assembly errors
2Measurement precision
If the IV tube is inserted into the sensor, then air bubble detection is enabled, but tubing creep over time causes uncoupling and false alarms
Solution Approach 1:
The sensor is pre-positioned and secured within the pump cassette body during manufacturing. The IV tube is pre-aligned with the sensor opening and inserted in a single action, ensuring optimal coupling is established before the infusion begins, eliminating the need for continuous adjustment
Solution Approach 2:
The sensor opening geometry is designed to match and accommodate the IV tube outer diameter with precise tolerances. The complementary shapes ensure a stable, repeatable coupling that maintains acoustic contact throughout the infusion duration without creeping or shifting
3Measurement precision
If air bubbles become stationary within the sensor gap, then acoustic short circuit occurs, but this results from non-optimization of fluid flow path
Solution Approach 1:
The sensor opening is positioned at a specific location in the fluid path where air bubbles naturally accumulate due to gravity and flow dynamics. The local geometry around the sensor opening is optimized to ensure air bubbles pass through the acoustic beam in a controlled manner that prevents stationary positioning and acoustic short circuits
Solution Approach 2:
The fluid flow path is designed with three-dimensional features including angled entry/exit ports and varying cross-sections that guide air bubbles through the sensor gap in a specific trajectory. This dimensional optimization ensures bubbles traverse the acoustic beam quickly without becoming stationary, maintaining detection accuracy
4Measurement precision
If the sensor is calibrated to specific tubing material, then detection accuracy is improved, but manufacturing variations in tubing material properties lead to non-optimization and false alarms
Solution Approach 1:
The sensor is designed with a universal coupling interface that accommodates multiple IV tubing materials and diameters. The sensor opening geometry and acoustic beam characteristics are optimized to work effectively with various tubing materials (PVC, polyethylene, polypropylene) without requiring separate calibration for each material type
Solution Approach 2:
The sensor system incorporates adjustable acoustic parameters including frequency, power, and beam focusing that can be optimized for different tubing materials. The pump control system allows parameter adjustment to accommodate variations in tubing acoustics while maintaining accurate air bubble detection across different material types
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 effectively detects air bubbles with improved accuracy and reliability, reducing false alarms and ensuring consistent performance across different IV tubing materials, while simplifying the insertion process and maintaining sensor alignment.
Implementation Method 1
an acoustic sensor disposed within the pump cassette recess, the acoustic sensor comprising a transmitter and a receiver
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
A pump cassette body for detecting air bubbles in a fluid pathway, comprises an upstanding flow director vane, a fitment integrally molded into the pump cassette body, wherein the fitment comprises a base integrally molded into the pump cassette body, an elastomeric member attached to the base, and a housing at least partially surrounding the elastomeric member, wherein the elastomeric member is co-molded to the housing.