Filling Dimensionally Unstable Plastic Containers
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Solution Overview
Problem
Dimensionally unstable plastic containers pose challenges in filling due to fluctuating capacities and headspace volumes, leading to inconsistent filling heights and internal pressures, which are perceived as quality defects by consumers.
Innovation Solution
The method involves prestressing dimensionally unstable plastic containers with gas before determining their volume, allowing for the creation of similar conditions to filled containers, and using this volume to determine the filling quantity and gas amount, ensuring consistent filling and internal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If lightweight plastic containers are used to reduce weight, then weight savings are achieved, but container volume becomes unstable and fluctuates
Solution Approach 1:
The container is prestressed with gas before the filling process to establish a reference volume under conditions similar to the final filled state. This preliminary action compensates for the dimensional instability of lightweight containers by pre-defining their volume characteristics before actual filling occurs.
Solution Approach 2:
The internal pressure of the container is changed during prestressing to simulate the pressure conditions of the filled state. By adjusting the prestressing pressure to match or approximate the desired internal pressure of the filled container, the container's volume is stabilized under representative conditions.
2Productivity
If fixed volume filling is used for containers with fluctuating capacities, then filling process is simplified, but filling heights fluctuate and quality consistency deteriorates
Solution Approach 1:
The system uses optical or sensor-based measurement to determine the actual volume of each container after prestressing but before filling. This feedback information is then used to adjust the filling quantity individually for each container, ensuring consistent filling heights despite variations in container dimensions.
Solution Approach 2:
The container volume is determined in advance during the prestressing phase, before the actual filling operation. This preliminary volume determination allows the filling system to be pre-configured with the correct filling quantity for each container, eliminating the need for complex real-time adjustments during filling.
3Quantity of substance
If gas injection is used to compensate for headspace volume, then headspace utilization is improved, but the amount of gas required fluctuates and process complexity increases
Solution Approach 1:
The actual headspace volume is measured using optical sensors or imaging systems after filling. Based on this feedback, the gas injection system precisely controls the amount of gas to be injected, ensuring optimal headspace utilization while minimizing gas consumption. The system adapts to each container's specific geometry and filling level.
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 eliminates the need for additional control measurements during or after filling, ensures consistent filling heights and internal pressures, and allows for the production of containers with more uniform volumes, addressing the limitations of existing methods for dimensionally unstable containers.
Implementation Method 1
the unfilled container is pressurized (internally pressurized) with gas or a gas mixture from the inside
Data Source
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AI summary
The invention relates to a method for filling dimensionally unstable plastic containers (1, 21) with a liquid content. A plastic container is pretensioned with gas or a gas mixture, the volume of the plastic container (1, 21) in the pretensioned state being determined before the plastic container is filled. The invention also relates to a device for carrying out the method.