Ultrasonic Air Detection in Medical Pump Lines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Medical pumps face issues with nuisance alarms and bubble generation due to ultrasonic waves in fluid delivery lines, leading to unreliable air detection and accumulation of air bubbles during fluid delivery.
Innovation Solution
A medical pump system with adaptive air detection using multiple sensors and controlled ultrasonic signal transmission, where sensors are activated only during specific phases of the pumping cycle to minimize bubble creation and enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic waves are continuously transmitted through the fluid delivery line for air detection, then air detection capability is improved, but air bubbles are generated and accumulated in the fluid delivery line
Solution Approach 1:
The ultrasonic transmitter operates intermittently rather than continuously, transmitting ultrasonic waves only during specific phases of the pumping cycle (e.g., during the delivery phase). This periodic operation maintains air detection capability while significantly reducing the generation of air bubbles caused by continuous ultrasonic exposure.
2Measurement precision
If ultrasonic waves are transmitted during the pressurization phase, then air detection is enhanced, but bubble accumulation increases
Solution Approach 1:
The system selectively activates the ultrasonic transmitter during specific phases of the pumping cycle, avoiding transmission during the pressurization phase where bubble accumulation is most problematic. This phase-specific operation maintains detection accuracy during safe phases while minimizing bubble generation.
Solution Approach 2:
The system prevents bubble accumulation by anticipating the harmful effect of ultrasonic waves during pressurization. By proactively disabling the transmitter during this critical phase, the system avoids creating conditions that would lead to significant bubble accumulation before detection can occur.
3Reliability
If multiple air detection sensors are added to improve detection reliability, then air detection accuracy is improved, but device complexity increases
Solution Approach 1:
The existing fluid delivery line structure serves multiple functions: it acts as both the fluid conduit and the transmission medium for ultrasonic waves. This eliminates the need for separate dedicated sensor components, maintaining detection reliability while avoiding increased device complexity.
Solution Approach 2:
The system uses the existing acoustic properties of the fluid delivery line and its contents as a natural sensor medium. By detecting changes in ultrasonic wave transmission through the fluid rather than adding complex sensor arrays, the system achieves reliable air detection without increasing device complexity.
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 reduces nuisance alarms and effectively detects air in the fluid delivery line, minimizing bubble generation and accumulation while ensuring reliable air detection, thereby improving the accuracy and reliability of fluid delivery.
Implementation Method 1
The transmitter transmits an ultrasonic signal which travels through the fluid delivery line, and which is received by the receiver on the opposite side of the fluid delivery line from the transmitter
Implementation Method 2
The signal transmitted by the transmitter and received by the receiver is modified or affected by the physical elements (the fluid delivery line, air within the fluid delivery line, fluid within the fluid delivery line, etc.) the signal encounters between the transmitter and the receiver
Data Source
AI summary
A method and pump that accurately senses air in a fluid delivery line pulses or activates and deactivates the air sensor(s) multiple times during the pumping phase of the fluid delivery cycle and can generate alarms based upon a single indication or a cumulative indication of air in the line. The pump can include multiple air sensors spaced along the delivery line so that the method can use the multiple signals therefrom to distinguish real moving air bubbles from false positives and/or air bubbles adhered to the inner wall of the line.