External Pressure Sensing for Flexible Irrigation Containers

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Solution Overview

Problem

Current technologies face challenges in accurately measuring pressure on the external surface of flexible containers used for irrigation during surgical procedures, particularly in ophthalmic surgeries, as existing methods lack precision and reliability in determining the pressure applied to these flexible containers.

Innovation Solution

A device comprising a squeeze plate and a pressure sensor module that applies pressure to a flexible container, utilizing force sensors, capacitive sensors, and a load cell to measure the force exerted on the container, allowing for precise pressure measurement through the calculation of force and contact area, with optional features like a hinged bag contact plate and a fluid-filled membrane for distributed pressure measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If external pressure sensing is implemented on flexible containers, then irrigation pressure control is improved, but measurement precision deteriorates due to the flexible surface deforming under pressure

Engineering Contradiction:
Improveirrigation pressure controlVSAvoidpressure measurement accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

A pressure distribution bag filled with fluid is introduced as an intermediary between the flexible irrigation container and the load cell. This mediator transfers and distributes the pressure from the flexible container surface to the rigid load cell through fluid transmission, enabling accurate measurement while isolating the sensor from surface deformation issues

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical contact sensing with fluid-based pressure transmission. Instead of mechanically attaching sensors to the flexible container surface, the system uses hydraulic pressure transmission through the fluid-filled distribution bag to convey pressure information to the load cell

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

2Measurement precision

If pressure sensors are integrated into the irrigation system, then pressure measurement capability is improved, but device complexity increases due to additional components

Engineering Contradiction:
Improvepressure measurement capabilityVSAvoidsystem component count
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The pressure distribution bag serves multiple functions simultaneously: it acts as a pressure transmission medium, a pressure equalization device, a mechanical interface between flexible and rigid components, and a cushioning element. This multi-functionality reduces the need for separate specialized components

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

Solution Approach 2:

The patent combines the pressure distribution function and the pressure measurement function into a single integrated system. The load cell both distributes pressure uniformly across the container surface and simultaneously measures the total force, eliminating the need for separate sensing and distribution mechanisms

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

Enables accurate and reliable measurement of pressure on flexible containers, ensuring consistent and controlled irrigation pressure during surgical procedures, enhancing the precision and safety of fluid delivery systems.

Implementation Method 1

The force sensor may include a capacitive sensor in contact with the flexible container

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Implementation Method 2

an internal load cell with a fluid separating the membrane from the internal load cell such that a force exerted on the membrane is transmitted to the internal load cell through the fluid

Methodology Applied
Scientific EffectHydraulic pressure transmission: Pascal's Law

Data Source

PatentEP2887978B1Systems and methods for external pressure sensing
Publication Date: 2017.06.14 ALCON RESEARCH LTD
  • EP2887978B1 patent drawingFigure 1
  • EP2887978B1 patent drawingFigure 2a~2b
  • EP2887978B1 patent drawingFigure 3

AI summary

In various embodiments, a device for delivering pressurized irrigation may include a squeeze plate and a pressure sensor module. The squeeze plate may move relative to the pressure sensor module to apply pressure to a flexible container (e.g., a bag of irrigation fluid) between the squeeze plate and the pressure sensor module. The pressure sensor module may include a pressure sensor to measure a force exerted on the pressure sensor module by the flexible container as pressure is applied to the flexible container from the squeeze plate. In some embodiments, the pressure sensor module may include a bag contact plate and the pressure sensor may measure a force exerted on the bag contact plate by the flexible container located between the bag contact plate and the squeeze plate. In some embodiments, the pressure sensor may sense a pressure associated with the flexible container without an intervening bag contact plate.