Infusion Flow Control via Weight and Optical Sensing
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Solution Overview
Problem
Infusion pumps face challenges in accurately controlling fluid flow rates due to reliance on motor RPM measurements, which can be affected by tubing cross-sectional area changes and mechanical precision requirements, leading to potential overdosing and air embolism risks, with existing sensors prone to false alarms and reliability issues.
Innovation Solution
An infusion apparatus using a combination of weight and optical sensors to estimate flow rates by measuring the weight of the IV container and counting fluid drops, with a flow control mechanism adjusting based on these estimates to ensure accurate delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If motor RPM is used to compute fluid flow rate, then the flow rate can be estimated based on motor speed, but errors occur due to tubing cross-sectional area changes and mechanical precision requirements
Solution Approach 1:
The patent replaces the mechanical measurement system (motor RPM sensing) with an optical measurement system (optical sensor detecting tubing movement). This substitution eliminates the accumulation of mechanical errors from motor speed measurements and directly measures the actual fluid displacement through optical detection of tubing position changes, thereby resolving the contradiction between productivity and measurement precision.
2Manufacturing precision
If precision bearings and mechanical features are used to ensure precise tubing location, then positioning accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical positioning features (precision bearings, mechanical guides) with an optical sensing system that non-contactively detects tubing position. The optical sensor measures tubing displacement through light interaction, eliminating the need for precision mechanical components while achieving equivalent or superior positioning accuracy, thus resolving the contradiction between manufacturing precision and device complexity.
3Object-affected harmful factors
If sensors are added to detect air in tube set, then air embolism detection capability improves, but false alarms and reliability issues increase
Solution Approach 1:
The patent replaces unreliable air detection sensors with an optical measurement system that detects air bubbles through their refractive index differences. The optical sensor identifies air presence by detecting changes in light transmission or reflection patterns, providing more reliable air embolism detection without the false alarms associated with electronic sensors, thus resolving the contradiction between harmful factor detection and system reliability.
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 provides a high degree of accuracy in fluid flow control, preventing overdosing and reducing the risk of air embolism by using dual sensing mechanisms to accurately regulate the flow rate, thereby ensuring precise and reliable medical fluid delivery.
Implementation Method 1
an optical sensor that generates a second signal in response to detecting the drops of the fluid
Implementation Method 2
a weight sensor that generates a first signal in response to measuring a weight of the fluid-container
Data Source
AI summary
An infusion apparatus includes a housing and a chamber configured to be connected to the housing. The apparatus further includes a weight sensor coupled to a load connector connected to the housing and an optical sensor disposed in the housing. The weight sensor is configured to generate a first signal based on a measured weight of the fluid container attached to the housing in a weight-bearing configuration. The optical sensor is configured to generate a second signal based on detecting drops of the fluid traversing the chamber. The apparatus also includes a flow control mechanism to control a flow rate of the fluid into an outlet channel. The apparatus includes one or more processing devices configured to perform operations including transmitting a control signal to the flow control mechanism to adjust the flow rate.