Piezoelectric Pump Feedback for NPWT Fluid Contamination Detection

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Solution Overview

Problem

Existing negative pressure wound therapy (NPWT) devices lack effective mechanisms to detect fluid contamination, which can damage internal components if not addressed promptly.

Innovation Solution

Incorporating a piezo-electric pump in parallel with the diaphragm pump to monitor fluid contamination through feedback signals, allowing the controller to cease operation of the diaphragm pump and alert caregivers when fluid is detected, thereby preventing damage to the NPWT device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a piezo-electric pump is added in parallel to detect fluid contamination, then the reliability of fluid detection is improved, but the device complexity increases

Engineering Contradiction:
Improvefluid contamination detectionVSAvoidpump system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A piezo-electric pump is introduced as an intermediary sensing device in parallel with the diaphragm pump. This piezo-electric pump acts as a mediator that detects fluid contamination through its electrical feedback signals without interfering with the primary therapeutic function of the diaphragm pump, thus improving detection reliability while maintaining system modularity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system utilizes electrical feedback signals from the piezo-electric pump to detect fluid contamination. The controller monitors these feedback signals to determine pump status and detect contamination events, enabling automatic response without requiring additional complex sensing mechanisms

Inventive Principle:
Principle #23Feedback

2Reliability

If the diaphragm pump is shut off upon detecting fluid contamination, then the damage to components is prevented, but the productivity of wound therapy is reduced

Engineering Contradiction:
Improvecomponent protectionVSAvoidwound therapy continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system applies preliminary anti-action by detecting fluid contamination through the piezo-electric pump's feedback signals and proactively shutting off the diaphragm pump before fluid can cause damage to internal components. This preventive shutdown protects the pump and associated components from fluid-related damage while the system alerts the user to address the contamination issue

Inventive Principle:
Principle #9Preliminary anti-action

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 effectively detects fluid contamination, preventing damage to NPWT device components and reducing repair costs and time, while ensuring continued operation and safety.

Implementation Method 1

a piezo-electric pump for fluid detection that is fluidly coupled in parallel with the diaphragm pump

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP4294474B1Systems for detecting fluid contamination in a wound therapy system
Publication Date: 2026.03.11 KCI MFG UNLIMITED CO
  • EP4294474B1 patent drawingFigure 1A
  • EP4294474B1 patent drawingFigure 1B
  • EP4294474B1 patent drawingFigure 2

AI summary

A negative pressure wound therapy (NPWT) system includes a therapy unit (102), a first pump (112), a piezo-electric pump (116), and a controller (202). The first pump (112) is configured to draw a negative pressure at a wound site (105) through a first tubular member (122). The piezo-electric pump (116) is fluidly coupled with the first tubular member (122) through a bypass tubular member (124) and is configured to detect a fluid indication. The controller (202) includes processing circuitry configured to obtain feedback signals from the piezo-electric pump (116) and determine if fluid is present at the piezo-electric pump (116) based on the feedback signals.