IV Drip Chamber Load Cell Sensing for Accurate Flow Measurement

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing IV drip rate measurement systems are inaccurate due to human error in manual drop counting and do not account for variations in droplet size and volume, leading to over- or under-estimation of fluid flow rates.

Innovation Solution

A drip rate measurement system using a strain gauge-based load cell transducer to measure the actual weight of IV fluid droplets, converting this into an electrical signal processed by a controller to output accurate drip rate, flow rate, and volume parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual drop counting is used to determine fluid flow rate, then the method is simple to implement, but it is inaccurate due to human error and does not account for variations in droplet size

Engineering Contradiction:
Improvedrip rate measurement accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the manual mechanical counting method with an electrical sensing system. A load cell transducer converts the mechanical weight of droplets into an electrical signal, which is then processed by a controller to determine drip rate. This substitution eliminates human error in counting while providing continuous, accurate measurement of actual fluid delivery.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a load cell transducer as an intermediary between the droplets and the measurement system. This transducer acts as a mediator that converts the physical weight of individual droplets into measurable electrical signals, enabling precise measurement of drip rate without direct human intervention in the counting process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If continuous monitoring is implemented to improve measurement accuracy, then measurement precision improves, but time consumption increases

Engineering Contradiction:
Improvedrip rate measurement accuracyVSAvoidcontinuous monitoring time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements continuous monitoring of drip rate through the load cell transducer system, which continuously measures the weight of droplets as they fall. This continuous action provides ongoing accurate measurement without requiring periodic manual intervention, thereby reducing overall time loss while maintaining high measurement precision throughout the fluid administration process.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The measurement system performs self-service by automatically detecting, measuring, and processing drip rate information without requiring continuous human monitoring. The load cell transducer and controller work autonomously to provide accurate measurements, freeing medical personnel from time-consuming manual counting while maintaining measurement precision.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If drop count is multiplied by standard volume to estimate flow rate, then the calculation is simple, but it over- or under-estimates actual fluid flow due to droplet size variations

Engineering Contradiction:
Improvefluid flow rate accuracyVSAvoidmeasurement method simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the simple but inaccurate method of multiplying drop count by standard volume with an electrical measurement system. The load cell transducer directly measures the actual weight of each droplet, and the controller calculates the true flow rate based on these direct measurements, eliminating estimation errors while maintaining operational simplicity through automated calculation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from indirect drop counting to direct weight measurement. By measuring the actual weight of droplets using the load cell transducer and converting this to volume through density relationships, the system accurately determines fluid flow rate without relying on standard volume assumptions, thereby improving precision while keeping the operation simple through automated processing.

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

Provides precise drip rate measurements by accounting for droplet weight, reducing errors associated with manual counting and variations in droplet size, and eliminating the need for continuous monitoring.

Implementation Method 1

A drip rate measurement system using a strain gauge-based load cell transducer to measure the actual weight of IV fluid droplets, converting this into an electrical signal

Methodology Applied
Scientific EffectStrain gauge: Piezoresistive Effect

Data Source

PatentEP4237036B1Systems and apparatus for drip rate measurement for medical fluid administration
Publication Date: 2025.12.24 CAREFUSION 303 INC
  • EP4237036B1 patent drawingFigure 1~2A
  • EP4237036B1 patent drawingFigure 2B~3B
  • EP4237036B1 patent drawingFigure 4

AI summary

A system for measuring drip rate may include a drip chamber device comprising an elongated body including an inner surface defining a chamber, and a drip rate measurement device. The drip chamber may be fluidly coupled to a container containing an IV fluid configured to drip droplets of the IV fluid into the chamber. The drip rate measurement device may include a housing configured to be mounted to the elongated body of the drip chamber, and a load cell transducer mounted in the elongated body and extending into the chamber. The load cell transducer may be configured to measure a weight of the droplets of the IV fluid and convert the weight into an electrical signal. The drip rate measurement device may further include a controller electrically coupled to the load cell transducer to process the electrical signal and output at least one parameter associated with the IV fluid.