Plastic Container Base Diaphragm for Pressure Accommodation

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Solution Overview

Problem

Plastic containers face challenges in accommodating internal pressures during elevated temperature processing such as hot-filling, pasteurization, and cooling, which can lead to structural deformation or failure due to headspace pressure and vacuum formation.

Innovation Solution

The design of a blow-molded plastic container with a base configuration that includes a diaphragm or inner wall capable of moving in response to pressure variations, featuring a bearing portion, up-stand wall, and inner wall that can flex or move to compensate for increased and decreased pressures, preventing structural damage and maintaining container integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid base structure is used in plastic containers, then structural strength is improved, but the container cannot accommodate internal pressure variations during hot-filling and cooling processes

Engineering Contradiction:

Improvestructural strengthVSAvoidpressure accommodation capability

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The base structure incorporates a movable diaphragm that can dynamically change position in response to internal pressure variations. The diaphragm moves downward under headspace pressure during hot-filling and upward under vacuum during cooling, allowing the rigid base structure to adapt to changing pressure conditions without compromising overall structural strength.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The diaphragm is constructed as a flexible thin film element within the base structure. This flexible component can deform and move to accommodate pressure changes while the surrounding rigid base structure maintains overall container strength and stability.

Inventive Principle:

Principle #30Flexible shells and thin films

2Ease of manufacture

If a smooth base surface is used from bearing portion to lower label stop, then ease of manufacture is improved, but pressure accommodation capability is reduced

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidpressure variation tolerance

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The base structure is segmented into different functional zones: a smooth bearing portion for stability, an up-stand wall providing structural support, and an inner wall containing the diaphragm for pressure accommodation. This segmentation allows each zone to be optimized for its specific function while maintaining overall manufacturing simplicity.

Inventive Principle:

Principle #1Segmentation

3Speed

If the diaphragm is positioned at a steep angle, then response to pressure variation is faster, but structural stability is reduced

Engineering Contradiction:

Improvepressure response speedVSAvoidstructural stability

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The diaphragm is positioned at a controlled angle of 3-15 degrees relative to the horizontal plane. This specific angular parameter optimizes the balance between pressure response speed and structural stability, allowing the diaphragm to move efficiently in response to pressure changes while maintaining adequate structural support from the surrounding base structure.

Inventive Principle:

Principle #35Parameter changes

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 effectively accommodates pressure changes within the container, preventing deformation and ensuring the container remains functional and safe during hot-filling, pasteurization, and cooling processes, thereby enhancing its durability and usability.

Implementation Method 1

The diaphragm is constructed and operative to move downward in response to the headspace pressure

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 2

The diaphragm is also constructed and operative to move upward in response to the vacuum

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 3

Plastic containers having base portions constructed and operative to accommodate internal pressures within the container due to elevated temperature processing, such as hot-filling, pasteurization, and/or retort processing

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS9994378B2Plastic containers, base configurations for plastic containers, and systems, methods, and base molds thereof

Publication Date: 2018.06.12 CO2 PAC

AI summary

Plastic containers, base configurations for plastic containers, and systems, methods, and base molds thereof. Plastic containers have base portions constructed and operative to accommodate internal pressures within the container due to elevated temperature processing, such as hot-filling, pasteurization, and/or retort processing. Plastic containers can also be constructed and operative to accommodate internal pressures within the filled container resulting from subjecting the filled plastic container to cooling or cool-down processing.