Nested Preform Assembly for Bag-in-Bottle Aerosol Containers
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Solution Overview
Problem
The existing manufacturing process for bag-in-bottle plastic aerosol containers using nested preforms is inefficient due to the need for multiple steps and equipment requirements, including separate operations for blow molding and propellant charging, which increases time and cost, and can lead to preform separation during shipping and handling.
Innovation Solution
A nested preform assembly with a friction fit between the inner and outer preforms, which eliminates the need for additional assembly steps and materials, and allows for simultaneous blow molding of both preforms, while incorporating a design with ribs and notches to maintain alignment and prevent separation, and channels for propellant charging and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If nested preforms are shipped and warehoused separately, then storage and transport are simplified, but the preforms become separated and require re-assembly
Solution Approach 1:
The patent applies nesting by placing the inner preform inside the outer preform, allowing both preforms to be transported and stored as a single integrated unit. This eliminates the need for separate storage and handling of individual preforms, preventing separation while maintaining manufacturing simplicity.
Solution Approach 2:
The patent implements preliminary assembly of nested preforms before shipping, so that the preforms are already positioned and secured in their final configuration. This preliminary action ensures they remain nested during transport and storage, eliminating the need for re-assembly at the destination.
2Ease of manufacture
If separate operations are used for blow molding and propellant charging, then equipment requirements are met, but manufacturing time and cost increase
Solution Approach 1:
The patent merges the blow molding and propellant charging operations into a single integrated process. The preforms are blow molded and charged with propellant in one continuous operation, eliminating the need for separate equipment and operations. This combines multiple functions into a unified manufacturing step, improving productivity while maintaining equipment capabilities.
Solution Approach 2:
The patent performs propellant charging as a preliminary action during the blow molding process itself, rather than as a separate post-processing step. The propellant is introduced into the preforms while they are being formed, combining these operations and eliminating subsequent handling and transport steps.
3Manufacturing precision
If high pressure blow molding equipment is used, then container formation is achieved, but equipment cost and complexity increase
Solution Approach 1:
The patent segments the blow molding process into two distinct pressure stages: a low pressure initial blow to form the basic container shape, and a high pressure final blow to achieve the final precise dimensions and wall thickness. This segmentation allows the use of simpler equipment for the first stage and only applies high pressure equipment where absolutely necessary for final formation, reducing overall equipment complexity while maintaining manufacturing precision.
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
This solution reduces the number of manufacturing steps, minimizes preform separation during handling, and enables efficient propellant charging, thereby streamlining the production process and reducing costs while maintaining the benefits of nested preforms.
Implementation Method 1
The inner preform and the outer preform create a friction fit that prevents relative motion between them
Implementation Method 2
Blowmolding typically requires two steps, a low pressure step followed by a high pressure step
Data Source
Figure 1A~1DD
Figure 1AE~1DDE
Figure 1F~3DD
AI summary
A plural preform assembly (20) having nested preforms (3040) with an inner preform (40, 42, 44) and an outer preform (30, 32, 34, 44). The preforms (3040) are sealably joined together, defining a volume between the preforms (3040). Propellant (40) is disposed in the volume between the preforms (3040). The preforms (3040) are later blow molded to provide a bag (92) in bottle, bottle in bottle or similar container. The propellant (40) charge is already present when blow molded, preventing the need for a later propellant (40) filling step.