Desiccant Canister Snap-Fit Cap Design

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Solution Overview

Problem

Mechanically assembled desiccant canisters face issues with mechanical connection strength under load conditions, leading to potential deformation and contamination, while heat treatment methods can damage the membrane and affect the active material's performance.

Innovation Solution

A cylindrical canister with a snap connection using unperforated membrane regions and reinforcing ribs, allowing for adjustable gas exchange kinetics and enhanced structural integrity without the need for specific orientation during assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If mechanical assembly is used to connect the cap to the canister body, then the canister is easy to manufacture and assemble, but the mechanical connection strength is insufficient under load conditions

Engineering Contradiction:
Improveease of assemblyVSAvoidmechanical connection strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The cap is divided into multiple functional elements: a rigid outer cap structure, an inner cap with membrane, and a separate grommet component. This segmentation allows each part to be optimized for its specific function while maintaining ease of assembly through snap-fit connections.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cap assembly uses composite construction combining rigid plastic material for structural strength, flexible membrane material for gas permeability, and elastomeric grommet material for sealing and shock absorption. This composite approach resolves the contradiction by combining materials with different properties to achieve both strength and ease of assembly.

Inventive Principle:
Principle #40Composite materials

2Strength

If heat treatment or welding is used to join the cap to the canister body, then the connection strength is improved, but the membrane and active material are damaged

Engineering Contradiction:
Improveconnection strengthVSAvoidheat damage to membrane and active material
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent replaces thermal joining methods (welding, heat treatment) with mechanical snap-fit connections. The cap and canister body are joined through elastic deformation of the grommet and snap portions, achieving strong connection without thermal exposure that would damage the membrane and active material.

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

Solution Approach 2:

The grommet acts as an intermediary component between the cap and canister body, providing both the sealing function and the mechanical connection. Its elastic properties allow it to absorb assembly forces and create a secure bond without requiring heat treatment, thus protecting the heat-sensitive membrane and active material.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If perforated membranes are used in the cap, then gas exchange kinetic is improved, but fine particles can pass through and contaminate the container contents

Engineering Contradiction:
Improvegas exchange kineticVSAvoidparticle contamination
Core Design Contradiction:
SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent uses a flexible, substantially unperforated membrane in the inner cap instead of perforated membranes. The membrane's flexibility and molecular-level porosity allow gas exchange kinetics while its continuous structure prevents passage of fine particles, resolving the contradiction between gas exchange speed and particle containment.

Inventive Principle:
Principle #30Flexible shells and thin films

4Strength

If reinforcing ribs are added to the cap to increase stiffness, then the cap strength is improved, but the cap must be mounted in a specific orientation

Engineering Contradiction:
Improvecap stiffnessVSAvoidassembly orientation flexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The grommet serves multiple functions: providing sealing, enabling mechanical connection through snap-fit, and allowing rotational freedom. This multi-functionality ensures the cap can be assembled in any orientation while maintaining structural integrity and sealing performance, resolving the contradiction between stiffness and assembly flexibility.

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

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 solution provides a robust, leak-tight, and flexible canister design that maintains the active material's capacity and prevents contamination, with adjustable gas exchange rates and reduced production complexity and costs.

Implementation Method 1

The top wall and/or bottom wall and/or at least one of the at least one sidewall comprises at least one membrane region with a predetermined permeability to a defined gaseous substance

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 2

The fixing portion comprises an elevated or recessed snap portion around its outer periphery which is shaped corresponding to a mating geometry around the inner sidewall surface of the sidewall of the canister body so as to form a snap connection with the canister body

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

desiccant material which adsorbs moisture from the air

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 4

oxygen scavenger, a desiccant or another functional material

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP2895254B1Canister for containing an active material
Publication Date: 2018.01.24 CLARIANT HEALTHCARE PACKAGING (FRANCE) SAS
  • EP2895254B1 patent drawingFigure 1~2
  • EP2895254B1 patent drawingFigure 3~4
  • EP2895254B1 patent drawingFigure 5~7

AI summary

A canister including a canister body containing a bottom wall and at least one sidewall with inner and outer sidewall surfaces and an upper rim, and a closing element containing a top wall with an outer surface and an inner surface, and a fixing portion surrounding the top wall. The top wall or the bottom wall or at least one sidewall include a membrane region with a predetermined permeability. The fixing portion includes an elevated or recessed snap portion around its outer periphery shaped to correspond to the inner sidewall surface of the sidewall of the cylindrical canister body and form a snap connection with the canister body. The closing element is fixed to the canister body such that the outer surface of the top wall does not extend beyond the upper rim of the sidewall of the canister body.