NPWT Canister Volume Detection via Airflow Measurement

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Solution Overview

Problem

Current negative pressure wound therapy (NPWT) systems require user input or scanning to estimate the volume of a canister, which can lead to errors and is inconvenient, especially when canisters lack markings or identifiers.

Innovation Solution

The NPWT system automatically estimates the volume of a canister by measuring airflow or pressure changes during the initial operation, using pre-stored model curves to identify the canister size, and prevents operation if the volume exceeds safe limits, thereby eliminating the need for user input and reducing errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual user input or scanning is used to determine canister volume, then the system can identify canister size, but the process becomes complex and prone to errors

Engineering Contradiction:
Improvecanister volume identification accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system automatically determines canister volume through pump operation and airflow measurement without requiring user input or external scanning devices. The canister itself provides the measurement data through its physical response to vacuum application, making the system self-sufficient and eliminating complex user interaction requirements.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual scanning or input mechanisms with a pneumatic measurement system. Instead of using optical scanners or manual data entry, the system uses the pump to create negative pressure and measures airflow characteristics to automatically determine canister volume, substituting mechanical/optical systems with a pneumatic-field-based approach.

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

2Ease of operation

If manual user input is required for canister volume, then the system can operate, but ease of operation is reduced

Engineering Contradiction:
Improvecanister volume setup convenienceVSAvoidoperation safety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs automatic canister volume determination through pump operation and airflow measurement, eliminating the need for manual user input. This self-service approach improves ease of operation while maintaining reliability through automated safety checks that prevent operation with improperly sized canisters.

Inventive Principle:
Principle #25Self-service

3Device complexity

If the system operates without volume detection, then simplicity is maintained, but harmful factors increase due to unsafe operations

Engineering Contradiction:
Improvesystem simplicityVSAvoidunsafe operation risk
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The system performs canister volume determination as a preliminary step before initiating therapeutic pump operation. By measuring airflow characteristics during an initial pump phase, the system identifies whether the canister is appropriately sized before committing to full therapy operation, preventing unsafe conditions from developing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses airflow measurement feedback during pump operation to determine canister volume and validate safe operating conditions. The controller continuously monitors airflow characteristics and uses this feedback to either proceed with therapy or prevent operation if the canister is improperly sized, eliminating harmful factors while maintaining system simplicity.

Inventive Principle:
Principle #23Feedback

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 solution provides a reliable and user-independent method for estimating canister volume, preventing unsafe operations and reducing errors, allowing the NPWT system to function accurately without relying on canister markings or scanning elements.

Implementation Method 1

The pump is fluidly coupled to the canister and is configured to draw a negative pressure within an interior of the canister

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Data Source

PatentEP3938003B1Wound therapy system with fluid canister volume detection
Publication Date: 2024.09.25 SOLVENTUM INTELLECTUAL PROPERTIES CO
  • EP3938003B1 patent drawingFigure 1A
  • EP3938003B1 patent drawingFigure 1B
  • EP3938003B1 patent drawingFigure 2

AI summary

A wound therapy system includes a wound dressing fluidly connected to a fluid canister. The fluid canister is attached to a canister receiving attachment of a housing structure. A pump is fluidly coupled to the canister and is configured to draw a negative pressure within an interior of the canister. A controller of the wound therapy system is configured to operate the pump to apply a vacuum to the interior of the canister and to obtain one or more measurements representative of at least one or a flow rate of air that is exhausted from the canister interior, a pressure within the canister interior and pump ripple. The controller is configured to estimate the volume of the canister based on the comparison of the measured parameters against model data stored by the controller that is representative of the operation of the therapy system with canisters of varying volumes.