Dynamic Pressure Control for Plastic Preform Reservoirs
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Solution Overview
Problem
Existing methods for forming plastic preforms into containers are inefficient due to fixed pressure correction values, leading to deviations in actual reservoir pressure, increased air consumption, and underutilized recycling potential, especially at low pressure levels.
Innovation Solution
A method and apparatus that control pressure in reservoirs using two variables: an offset value and recycling time, prioritized based on operating states, to maintain target pressure and optimize recycling, reducing pressure fluctuations and air consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed offset values are used to control reservoir pressure, then the control system is simple, but the actual pressure deviates from target value especially at low pressure levels
Solution Approach 1:
The patent transitions from fixed static offset values to dynamic offset values that are continuously adapted based on the difference between actual and target pressure. The control variable is no longer constant but changes dynamically according to operating conditions, allowing the system to maintain pressure accuracy across varying pressure levels without increasing overall system complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the actual pressure is continuously measured and compared with the target pressure. The difference (deviation) is fed back to the control system, which then adjusts the offset value accordingly. This closed-loop feedback ensures that pressure deviations are corrected in real-time, significantly improving pressure control accuracy especially at low pressure levels where deviations were most problematic.
2Ease of manufacture
If fixed correction values are applied to all operating states, then the control method is simple, but air consumption increases and recycling potential is underutilized
Solution Approach 1:
The system dynamically adjusts the offset value based on the difference between actual and target pressure rather than applying a fixed correction value to all operating states. This dynamic adaptation allows the system to optimize air consumption in real-time, utilizing recycling potential more effectively while maintaining operational simplicity through automated control.
Solution Approach 2:
The patent changes the control parameter from a fixed offset value to a dynamically adjusted offset value that varies with operating conditions. By modifying this key parameter based on actual pressure measurements and target pressure differences, the system achieves optimized air consumption and recycling utilization without complicating the overall control methodology.
3Ease of operation
If fixed correction values are used, then the system is easy to operate, but pressure levels fluctuate and deviate from target especially below 6 bar
Solution Approach 1:
The system continuously monitors actual pressure and compares it with target pressure, using the deviation as feedback to adjust the offset value. This feedback mechanism automatically compensates for pressure fluctuations, ensuring stable pressure levels especially at low pressures below 6 bar where deviations were most significant, while requiring minimal operator intervention.
Solution Approach 2:
The control system performs self-adjustment by automatically modifying the offset value based on pressure deviations without requiring manual intervention. The system serves itself by detecting pressure instability and correcting it through dynamic offset adjustment, maintaining ease of operation while significantly improving pressure stability and reliability.
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 minimizes pressure differences and maintains constant pressure levels, reducing air consumption by up to 25% and fully utilizing recycling potential, with improved control over reservoir states.
Implementation Method 1
heated plastic preforms are usually expanded with a flowable medium and, in particular, with compressed air and thus formed into plastic containers
Implementation Method 2
a pressure in at least one reservoir is controlled, wherein a target pressure is compared with an actual pressure in this reservoir, and a value characteristic of this comparison is determined
Implementation Method 3
at least at times the flowable medium is returned from the plastic container to at least one of these reservoirs
Data Source
AI summary
The method wherein plastic preforms are formed into plastic containers by application of a flowable medium wherein the plastic preforms are biased with different pressure levels and the flowable medium is stored in at least two reservoirs and is supplied from these reservoirs to the plastic preforms, wherein at least one of these reservoirs is supplied with the flowable medium by a pressure supply device and wherein the flowable medium is returned at least temporarily from the plastic container to at least one of these reservoirs, wherein a pressure in at least one reservoir is controlled, and wherein a target pressure is compared with an actual pressure in this reservoir, and a value characteristic of this comparison is determined.