Dip Tube Fitting Reliability in Dispensing Pumps

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Solution Overview

Problem

The existing dispensing systems for bottles, particularly in perfumery, cosmetics, and pharmaceuticals, face reliability issues due to the difficulty in achieving a high clamping force for the dip tube assembly, especially with flexible and ductile materials, leading to potential misfitting and deformation during high-speed assembly processes.

Innovation Solution

The dispensing system incorporates a bore with an internal annular projection having a convergent lower part and a divergent upper part, facilitating the introduction of the dip tube with a low required fitting force, and an axial stop to maintain the material's elasticity, ensuring reliable fitting and easy molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a peripheral bead is added to the bore to increase clamping force, then the fitting reliability improves, but the manufacturing complexity and risk of deformation during molding increase

Engineering Contradiction:
Improvefitting reliabilityVSAvoidbore structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention applies local quality by creating an annular projection at a specific location within the bore to concentrate clamping force where needed. This projection provides localized structural reinforcement without modifying the entire bore geometry, thereby improving fitting reliability while maintaining overall manufacturing simplicity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bore is segmented into distinct functional zones: an upper portion with the annular projection for clamping, a convergent lower portion for guiding, and an axial stop region for positioning. This segmentation allows each zone to perform its specific function optimally without interfering with others, resolving the contradiction between reliability and complexity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the ring projects further inside the bore to increase clamping force, then the fitting reliability improves, but the risk of tube end deformation during fitting increases

Engineering Contradiction:
Improvefitting reliabilityVSAvoidtube end integrity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

Instead of uniformly projecting the ring throughout the bore, the invention creates a localized annular projection with specific dimensional characteristics. This localized approach provides sufficient clamping force at the critical fitting interface while avoiding excessive projection that would cause tube end deformation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The convergent lower portion of the bore is designed to preliminarily guide and position the dip tube before the fitting operation completes. This preliminary action ensures proper alignment and reduces the risk of deformation during the final clamping phase, allowing the annular projection to function effectively without causing tube end damage.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If high fitting force is applied to ensure proper fitting, then the fitting reliability improves, but the deformability of polymeric dip tube material causes fitting failures

Engineering Contradiction:
Improvefitting reliabilityVSAvoidpolymer material strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention changes the geometric parameters of the bore, specifically introducing an annular projection with controlled dimensions and a convergent lower portion. These parameter changes allow the bore to generate effective clamping force through a larger contact area and progressive deformation, reducing the peak force required and preventing polymer material failure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The convergent lower portion of the bore acts as a cushioning element that progressively deforms the dip tube material during fitting. This beforehand cushioning distributes the fitting force over a longer distance and time, preventing sudden stress concentrations that would exceed the polymer material's strength limits.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Productivity

If fitting speed is increased to meet assembly rate requirements, then productivity improves, but the fitting reliability decreases due to insufficient clamping time

Engineering Contradiction:
Improveassembly rateVSAvoidfitting reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The convergent lower portion of the bore performs preliminary guiding and positioning of the dip tube before the main fitting operation. This preliminary action ensures proper alignment is achieved quickly, allowing the subsequent clamping phase to be completed rapidly without sacrificing fitting quality, thus maintaining both high productivity and reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The annular projection creates a localized high-clamping-force zone that achieves secure fitting in a single rapid operation. This concentrated local quality allows the fitting to be completed quickly without requiring prolonged application of force, enabling high-speed assembly while maintaining fitting reliability.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP1915921B1Fluid distributing system with reliable fitting of the plunger tube
Publication Date: 2018.09.05 ALBEA LE TREPORT
  • EP1915921B1 patent drawingFigure 1~3

AI summary

The bottle has a transparent or translucent body (2) surmounted by a ring provided with an opening. A dispensing pump is associated with the opening, and has a pump body (6) on which a dip tube (7) is mounted via an association part. The pump body is made of transparent or translucent material. The tube is immersed in an alcoholic perfume solution (1) for supplying the pump with the solution to be dispensed. The tube is made of a material with base of fluorinated polymer e.g. polytetrafluoroethylene (PTFE) co-polymer block.