Pre-pressurized Liquid Injection for Lightweight Preform Blow Filling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for manufacturing thermoplastic polymer containers through blow moulding often result in breakage during the stretching and injection phases, particularly for lightweight preforms, due to inadequate control over the expansion process.
Innovation Solution
The method involves pre-loading a liquid to a predetermined pressure above atmospheric pressure, storing energy during this process, and releasing it to power the injection phase, which accelerates and controls the expansion of the preform, reducing the risk of breakage and enabling simultaneous blowing and filling of lightweight containers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the liquid is injected into the preform at atmospheric pressure, then the injection process is simple, but the preform breaks during stretching and injection phases
Solution Approach 1:
The liquid is pre-loaded into the injection circuit at a predetermined pressure above atmospheric pressure before the injection phase begins. This preliminary pressurization stores energy that is then released during injection, enabling controlled expansion of the preform without breaking it. The pre-action of pressurizing the liquid prepares the system for the subsequent injection phase, resolving the contradiction between simplicity and reliability.
2Productivity
If the liquid is pressurized before injection, then the preform expands faster and more controllably, but energy storage and release mechanisms are required
Solution Approach 1:
The system uses the liquid itself as the energy storage medium. When the liquid is pressurized before injection, the energy is stored in the compressed liquid and released automatically during the injection phase without requiring separate energy storage devices. The liquid circuit serves dual purposes: transporting the liquid and storing/releasing energy, thereby achieving fast expansion while minimizing added complexity.
3Productivity
If the preform is stretched and filled simultaneously, then the manufacturing process is efficient, but the preform is more prone to breaking
Solution Approach 1:
The method changes the pressure parameter of the injected liquid from atmospheric pressure to a predetermined pressure above atmospheric pressure. This parameter change enables the liquid to deliver higher energy during injection, allowing simultaneous stretching and filling to proceed faster while the controlled pressurization prevents preform breakage. The temperature of the preform is also maintained at a sufficiently high value to reduce damage risks during fast expansion.
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 approach allows for efficient and controlled expansion of thermoplastic polymer containers, reducing the risk of damage during the manufacturing process and enabling the production of lightweight containers that were previously difficult to manufacture.
Implementation Method 1
bringing the liquid to a predetermined pressure above the atmospheric pressure so that the thus pressurized or pre-loaded liquid is ready to be injected
Implementation Method 2
at least one part of the liquid circuit (flexible pipe or membrane, expansion tank, etc.) may be elastically deformable so that energy produced through pressurizing the liquid contributes to elastically deforming said at least one part when submitted to said increase in pressure
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention concerns a method of blowing and filling a container from a thermoplastic polymer preform, comprising: stretching a thermoplastic polymer preform (16) placed within a mould (12) during a stretching phase, starting an injection phase for injecting a liquid into the preform, the injection phase starting after the stretching phase has started, characterized in that prior to starting the injection phase the liquid is at a predetermined pressure above the atmospheric pressure.