Infusion Air Detection Frequency Tuning to Prevent ADC Saturation

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Solution Overview

Problem

Analog-to-digital converters in infusion systems can become over-saturated when operating at resonant frequencies, leading to reduced accuracy and reliability in detecting air in fluid delivery lines, causing potential errors and alarms.

Innovation Solution

The system operates sensors at a modified frequency different from their resonant frequency to reduce signal amplitude below the saturation level of the analog-to-digital converter, preventing over-saturation and improving detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensors operate at resonant frequency to maximize signal output, then detection sensitivity is improved, but analog-to-digital converter becomes over-saturated causing reduced measurement accuracy

Engineering Contradiction:
Improveair detection accuracyVSAvoidanalog-to-digital converter reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the operating frequency parameter of the sensor from the resonant frequency to a non-resonant frequency. This parameter change reduces the signal amplitude to a level that the analog-to-digital converter can process without over-saturation, while still maintaining sufficient detection capability for air in the fluid delivery line.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If signal amplitude is increased to improve detection capability, then sensor effectiveness is improved, but analog-to-digital converter over-saturation occurs causing errors and alarms

Engineering Contradiction:
Improvesignal detection capabilityVSAvoidover-saturation errors
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent adjusts the frequency parameter to optimize signal amplitude within the acceptable range of the analog-to-digital converter. By operating at a non-resonant frequency, the signal amplitude is reduced to prevent over-saturation errors and false alarms while maintaining adequate detection sensitivity.

Inventive Principle:
Principle #35Parameter changes

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

This approach enhances the reliability and accuracy of air detection in infusion systems by avoiding signal over-saturation, reducing errors, and ensuring accurate fluid delivery.

Implementation Method 1

The at least one sensor is operated at a modified frequency which is different than a resonant frequency of the at least one sensor

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentUS11596737B2Infusion system and method of use which prevents over-saturation of an analog-to-digital converter
Publication Date: 2023.03.07 ICU MEDICAL INC
  • US11596737B2 patent drawing
  • US11596737B2 patent drawing
  • US11596737B2 patent drawing

AI summary

To detect air in a fluid delivery line of an infusion system, infusion fluid is pumped through a fluid delivery line adjacent to at least one sensor. A signal is transmitted and received using the at least one sensor into and from the fluid delivery line. The at least one sensor is operated, using at least one processor, at a modified frequency which is different than a resonant frequency of the at least one sensor to reduce an amplitude of an output of the signal transmitted from the at least one sensor to a level which is lower than a saturation level of the analog-to-digital converter to avoid over-saturating the analog-to-digital converter. The signal received by the at least one sensor is converted from analog to digital using an analog-to-digital converter. The at least one processor determines whether air is in the fluid delivery line based on the converted digital signal.