Blowing Nozzle Sealed Chamber for Aseptic Parison Stretching
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Solution Overview
Problem
Existing devices for blowing and stretching plastic parisons in aseptic bottling lines fail to maintain a controlled-contamination environment, as they either link the sterile environment to the external environment or are incompatible with sterilization processes due to deformation of elastic bellows under pressure.
Innovation Solution
A device with a blowing nozzle and stretching rod configuration where the stretching rod is housed in a sealed chamber, allowing for easy sterilization and maintaining the rod's sterilized condition, while the activating means are located outside the controlled-contamination environment to prevent contamination, using magnetic coupling and pneumatic mechanisms for operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a blowing nozzle is used to inject air into the parison and guide the stretching rod, then the blowing and stretching functions are integrated, but the nozzle becomes a contamination channel linking the controlled environment to the external environment
Solution Approach 1:
The device is divided into two separate functional components: a blowing nozzle for air injection and a stretching rod for mechanical stretching. This segmentation allows the stretching rod to be isolated from the contamination channel, enabling it to be sterilized independently while the nozzle remains in the controlled environment.
Solution Approach 2:
The stretching rod is extracted from the blowing nozzle structure and given its own independent housing chamber. This extraction removes the stretching rod from the contamination pathway, allowing the nozzle to remain sealed within the controlled environment while the rod can be sterilized separately in its dedicated chamber.
2Ease of operation
If elastic bellows are used to house the stretching rod, then the rod can move freely, but the bellows deform under sterilizing pressure and cannot be reliably sterilized
Solution Approach 1:
The elastic bellows mechanical system is replaced with a rigid sealed chamber housing the stretching rod. This substitution eliminates the deformation problem under sterilizing pressure while maintaining rod movement capability through alternative mechanical means within the rigid structure.
Solution Approach 2:
The stretching rod chamber is given a specific rigid structure with localized flexibility only where needed for rod movement, rather than using entirely elastic bellows. This allows the chamber to withstand sterilizing pressures while still permitting the rod to move freely during operation.
3Device complexity
If driving components are located inside the controlled environment, then the mould operation is simplified, but lubrication causes accumulation of dirt and dust near the moulds
Solution Approach 1:
The driving components for the stretching rod are extracted from the controlled environment and placed in a separate chamber outside the sterile zone. This extraction eliminates the contamination source while the rod itself can still be sterilized, separating the lubricated mechanical components from the contamination-sensitive environment.
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 device effectively maintains low environmental contamination levels, allows for reliable sterilization of the stretching rod, and simplifies the structure with magnetic coupling and sealed chambers, preventing deformation under sterilizing pressures.
Implementation Method 1
The activating means are located outside the controlled-contamination environment and are magnetically coupled with the stretching rod
Data Source
AI summary
Device (1) for blowing and stretching a plastic parison (3) for obtaining a container, comprising:a blowing nozzle (4) having a first end (4a) to be applied to an inlet (3a) of said parison (3), said first end (4a) emerging in a controlled-contamination environment (5) wherein said parison (3) is blown;a stretching rod (2);means for injecting mid and high pressure air in said parison (3);a non-magnetic tube (7) secured to a second end (4b) of the blowing nozzle (4) and defining a chamber (8) for housing, at least partially, the stretching rod (2), said chamber (8) being tight-sealed relative to a contaminated area (22) from which said controlled-contamination environment (5) is isolated;a first magnet arrangement (9) and a second magnet arrangement (10) coupled together, said first magnet arrangement (9) being located outside said chamber (8) and said second magnet arrangement (10) being integral to said stretching rod (2) and located within said chamber (8).