Negative Pressure Wound Therapy Valve Control for Stable Pressure

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Solution Overview

Problem

Existing negative pressure wound therapy systems lack effective control mechanisms for maintaining optimal pressure levels and adjusting between negative and positive pressures to enhance wound healing and patient comfort.

Innovation Solution

A system with a controller that adjusts pressure by generating control signals based on pressure differences, using pulse-width modulation and proportional-integral-derivative calculations to operate valves, allowing for intermittent negative pressure therapy and controlled positive pressure application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a source of negative pressure is used to apply negative pressure to a wound, then wound healing is promoted, but pressure control precision is insufficient

Engineering Contradiction:
Improvewound healing effectivenessVSAvoidpressure control precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system incorporates a pressure sensor that continuously monitors the pressure under the wound dressing and feeds this information back to the controller. The controller compares the measured pressure with the desired pressure setting and adjusts the negative pressure source accordingly to maintain the target pressure level, thereby achieving precise pressure control while promoting wound healing

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the pressure parameter by transitioning between negative pressure and positive pressure modes based on therapeutic requirements. The controller can modify the pressure magnitude and direction (negative to positive) to optimize wound healing while maintaining precise control over the applied pressure levels

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If intermittent negative pressure therapy is applied, then patient comfort is improved, but pressure stability deteriorates

Engineering Contradiction:
Improvepatient discomfortVSAvoidpressure stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The system implements intermittent negative pressure therapy by periodically switching between negative pressure application and relief phases. The controller manages these periodic cycles to provide therapeutic benefits while allowing pressure stability during each phase, reducing patient discomfort through controlled intermittent treatment rather than continuous pressure

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts pressure levels and transitions between negative and positive pressure modes based on real-time wound conditions and therapeutic requirements. This dynamic control allows the system to maintain optimal pressure stability during treatment while adapting to changing patient needs and wound healing stages

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If positive pressure is supplied to adjust pressure levels, then pressure control accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvepressure control accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system employs a multi-functional valve that can operate in multiple modes: regulating negative pressure, introducing positive pressure, and controlling pressure transitions. This single valve component performs several pressure control functions that would otherwise require separate devices, thereby improving pressure control accuracy while minimizing the increase in device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system combines the negative pressure source, positive pressure source (via valve), pressure sensor, and controller into an integrated pressure control system. By merging these components into a coordinated system, the patent achieves high pressure control accuracy through synergistic operation while avoiding the complexity of fully separate, independent control systems

Inventive Principle:
Principle #5Merging (Combining)

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

Enhances wound healing by maintaining optimal pressure levels, reducing patient discomfort, and ensuring efficient operation of negative pressure wound therapy systems.

Implementation Method 1

The valve controls supply of positive pressure via the flow path to the wound dressing

Methodology Applied
Scientific EffectValve control: Valve

Implementation Method 2

The source of negative pressure provides negative pressure under the wound dressing

Methodology Applied
Scientific EffectNegative pressure: Vacuum

Implementation Method 3

The control signal can be a pulse-width modulation (PWM) signal, and the controller can vary a duty cycle of the PWM signal to operate the valve

Methodology Applied
Scientific EffectPulse-width modulation: Phase Modulation

Implementation Method 4

The controller can generate the control signal using a proportional-integral-derivative (PID) calculation, and an error of the PID calculation can be the pressure difference

Methodology Applied
Scientific EffectProportional-integral-derivative control: Feedback

Data Source

PatentEP3595736B1Pressure control in negative pressure wound therapy systems
Publication Date: 2025.07.23 SMITH & NEPHEW INC
  • EP3595736B1 patent drawingFigure 1
  • EP3595736B1 patent drawingFigure 2A
  • EP3595736B1 patent drawingFigure 2B

AI summary

Embodiments of negative pressure wound therapy systems and methods for operating the systems are disclosed. In some embodiments, a system includes a pump assembly, canister, and a wound dressing configured to be positioned over a wound. The pump assembly, canister, and the wound dressing can be fluidically connected to facilitate delivery of negative pressure to a wound. The system can additionally include a valve configured to control the introduction of positive pressure to the wound.