CMUT Sensor for Medical Pump Flow Rate Control
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Solution Overview
Problem
Current fluid delivery systems for medical pumps lack a highly integrated hybrid sensor system capable of monitoring multiple characteristics of tubing and fluid to adjust flow rates effectively, with existing ultrasonic sensors facing issues of high cost and impedance matching problems, and existing solutions for tubing wear compensation being costly and incomplete.
Innovation Solution
A system utilizing capacitive micromachined ultrasonic transducer sensors to determine tubing dimensions, fluid flow velocity, and fluid flow rate, with a processor adjusting the pump's operation to vary flow rates and detect air bubbles, incorporating flip-chip bonding for improved resolution and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional piezoelectric ultrasonic transducers are used for flow monitoring, then flow rate measurement capability is provided, but acoustic impedance mismatch causes poor coupling efficiency and high cost
Solution Approach 1:
The patent replaces conventional piezoelectric ultrasonic transducers with capacitive micromachined ultrasonic transducers (CMUTs). This substitution eliminates the acoustic impedance matching problems inherent in piezoelectric materials by using a capacitive structure that couples more efficiently to the fluid medium, thereby improving both measurement precision and manufacturing ease
Solution Approach 2:
The patent changes the fundamental operating parameters of the ultrasonic transducer by transitioning from piezoelectric to capacitive micromachined technology. This parameter change in the transducer type enables better acoustic coupling to the fluid and tubing system, resolving the impedance mismatch issue while maintaining flow measurement capability
2Adaptability or versatility
If multiple separate sensors are used to monitor tubing and fluid characteristics, then comprehensive monitoring capability is achieved, but system complexity and cost increase
Solution Approach 1:
The patent implements a multi-functional CMUT sensor system that can simultaneously perform multiple sensing functions including flow rate measurement, air bubble detection, and tubing characteristic monitoring. This universal sensor replaces what would otherwise require multiple separate specialized sensors, thereby reducing system complexity and cost while maintaining comprehensive monitoring capability
Solution Approach 2:
The patent merges multiple sensing functions into a single integrated CMUT-based sensor system. By combining flow measurement, bubble detection, and tubing monitoring capabilities into one unified sensor platform, the system reduces complexity and improves adaptability without requiring multiple separate sensor components
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 accurate and cost-effective flow rate adjustment and air bubble detection, enhancing the precision and reliability of fluid delivery while reducing system costs, maintaining consistent flow rates over time despite tubing wear and changes.
Implementation Method 1
a capacitive micromachined ultrasonic transducer sensor assembly adapted to operatively couple with the tubing to transmit and receive acoustic signals directed at or through the tubing
Implementation Method 2
transmit and receive acoustic signals directed at or through the tubing
Implementation Method 3
The controller determines the presence of air bubbles in the fluid within the tubing based on the acoustic signals from the sensor assembly
Data Source
AI summary
A system and method of varying the flow rate of fluid from a medical pump through tubing includes determining an inner diameter of the tubing and fluid flow velocity of fluid in the tubing with a controller based on acoustic signals received by a capacitive micromachined ultrasonic transducer sensor system and then determining and adjusting a fluid flow rate of fluid in the tubing with the controller. In addition, the same sensor system also detects air bubbles in the fluid in the tubing.