Capillary Fluid Venting Structure for Leak-Resistant Personal Care Implements

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Solution Overview

Problem

Existing fluid supply apparatuses and personal care implements suffer from leakage due to air expansion caused by temperature increases or pressure decreases, leading to unwanted fluid leakage.

Innovation Solution

A fluid supply apparatus with a housing containing a storage cavity and a capillary member, coupled with a vent tube having a primary vent passageway and multiple vent apertures, ensuring fluid cannot flow through the apertures at ambient temperature and pressure equilibrium, and maintaining spatial communication with the external atmosphere regardless of orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sealed storage cavity is used to store fluid, then fluid containment is improved, but pressure buildup from air expansion causes fluid leakage

Engineering Contradiction:
Improvefluid containmentVSAvoidfluid leakage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A hydrophobic membrane acts as an intermediary between the stored fluid and the venting system. The membrane allows air molecules to pass through for pressure equalization while repelling liquid fluid due to its hydrophobic properties, thus preventing fluid leakage while maintaining pressure balance in the storage cavity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The vent aperture dimensions are specifically designed to be small enough to prevent fluid flow at ambient temperature and pressure equilibrium, yet large enough to allow air passage. The hydrophobic membrane's surface tension parameters are selected to differentiate between gas and liquid phase behavior, enabling selective permeability based on physical state

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If vent apertures are added to relieve pressure, then fluid leakage is prevented, but fluid may flow through the apertures under certain conditions

Engineering Contradiction:
Improvepressure buildupVSAvoidfluid flow control
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The hydrophobic membrane serves as a selective intermediary that discriminates between air and fluid based on their different physical properties. It allows the vent apertures to function for pressure relief while blocking fluid passage through surface tension and hydrophobic effects

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The vent tube structure incorporates localized hydrophobic treatment on the membrane surface, creating regions with different wetting properties. This local quality modification ensures that the membrane surface repels fluid while permitting gas transmission through the same aperture structure

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the device is used in various orientations, then versatility is improved, but air pockets may block vent apertures in certain positions

Engineering Contradiction:
Improveusage orientationVSAvoidvent aperture accessibility
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The vent tube is segmented into multiple sections: the storage cavity interface, the hydrophobic membrane barrier, the vent aperture array, and the external vent passageway. This segmentation allows the apertures to be positioned strategically so that air can reach at least some apertures regardless of device orientation, maintaining venting functionality in all positions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The vent apertures are arranged in a three-dimensional pattern on the vent tube surface rather than a single plane. This spatial distribution in multiple dimensions ensures that gravity and orientation changes do not consistently block all aperture access paths, as air can approach from different directional vectors

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Prevents fluid leakage by allowing air to replace dispensed fluid, maintaining consistent flow and preventing pressure buildup within the storage cavity, thus ensuring reliable operation across various orientations and conditions.

Implementation Method 1

a channel formed of one or more wicking or capillary members extends through at least a portion of the oral care implement to deliver a fluid via one or more fluid outlets (e.g., formed in a head portion of the toothbrush) via capillary action

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

The vent apertures may be located and arranged on the vent tube such that irrespective of vertical and angular orientation of the housing relative to a gravitational vector at least one of the vent apertures is in spatial communication with the gas

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP3541238B1Fluid supply apparatus and personal care implement containing the same
Publication Date: 2025.11.12 COLGATE PALMOLIVE CO
  • EP3541238B1 patent drawingFigure 1
  • EP3541238B1 patent drawingFigure 2
  • EP3541238B1 patent drawingFigure 3

AI summary

A fluid supply apparatus with leakage protection. The apparatus includes a housing defining a storage cavity having a total volume including a fluid portion and a gas portion. The storage cavity extends along a cavity axis from a first end to a second end. A capillary member is fluidly coupled with the fluid. A vent tube having a primary vent passageway and a plurality of vent apertures is located in the storage cavity. The primary vent passageway forms a pathway from the vent apertures to the external atmosphere. Fluid cannot flow through the vent apertures at ambient temperature and pressure equilibrium. The vent apertures may be located and arranged on the vent tube such that irrespective of vertical and angular orientation of the housing relative to a gravitational vector at least one of the vent apertures is in spatial communication with the gas.