Preform Thermal Conditioning With Feedback Airflow Control
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Solution Overview
Problem
Existing thermal conditioning devices for preforms in the manufacturing of plastic containers face challenges in precisely controlling the nominal flow rate of cooling air, which can be affected by fan efficiency loss and filter clogging, leading to defects in the final containers.
Innovation Solution
Incorporation of measuring means within the air flow channels to monitor the actual flow rate and adjust the nominal flow rate accordingly, using control means to manage circulating means such as fans and ventilation systems, ensuring precise control and detection of malfunctions like filter clogging or fan aging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fans and ventilation systems are used to control air flow for cooling preforms, then cooling capability is provided, but over time fan efficiency is lost and filters become clogged causing nominal flow rate to deviate
Solution Approach 1:
The patent implements a feedback control system where a measuring device (anemometer) continuously monitors the actual air flow rate in the channel. The control unit receives this measurement and compares it to the nominal flow rate, automatically adjusting the fan speed via variable speed drives to compensate for filter clogging and fan efficiency loss, thereby maintaining reliable flow rate control over extended operational periods
Solution Approach 2:
The system performs preliminary measurement of the actual air flow rate before defects manifest in the final product. By continuously monitoring flow rate and detecting deviations early through the measuring device, the system can adjust fan operation in advance to prevent quality defects, rather than waiting for problems to occur
2Manufacturing precision
If variable speed drives are used to control fan rotational speed, then nominal flow rate can be managed, but precise control is difficult to maintain over time due to efficiency loss
Solution Approach 1:
The control unit receives real-time feedback from the anemometer measuring the actual air flow rate and automatically adjusts the variable speed drives to maintain the desired nominal flow rate, compensating for fan efficiency degradation and filter clogging to preserve manufacturing precision over time
Solution Approach 2:
The patent replaces purely mechanical flow rate control (fixed fan speeds) with an automated control system that uses electronic sensors (anemometer) and variable speed drives with electronic control. This substitution enables precise, dynamic adjustment of fan speed based on actual measured conditions, maintaining flow rate precision despite mechanical wear and filter clogging
3Object-affected harmful factors
If filters are used to clean air before circulation, then air quality is improved, but filters become clogged causing flow rate reduction
Solution Approach 1:
The measuring device continuously monitors the actual air flow rate downstream of the filters. When filter clogging causes flow rate reduction, the control unit detects this deviation and compensates by increasing fan speed to maintain the required nominal flow rate, thus preserving both air quality and flow quantity
Solution Approach 2:
The system performs preliminary detection of flow rate changes caused by filter clogging before they significantly impact production quality. By continuously measuring actual flow rate and comparing it to nominal values, the system can adjust fan operation in advance to compensate for filter resistance increases
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
Enhances the precision of air flow control, reduces defects in containers, and allows for predictive maintenance, optimizing energy usage and adherence to manufacturing specifications.
Implementation Method 1
at least one heating means oriented toward the transport volume
Implementation Method 2
This cooling is effected by circulating a flow of air, at ambient temperature
Data Source
AI summary
A thermal conditioning device for thermally conditioning preforms, comprising a heating module provided with an enclosure with a transport volume for said preforms; a heating means and a cooling means that are oriented toward the volume; a control means for controlling said heating and cooling means; said cooling means comprising a circulating means for circulating a flow of air with a nominal flow rate determined by said control means; a channel between said circulating means and said enclosure and leading toward said volume; wherein it comprises, along said channel, a measuring means for measuring the actual flow rate and an adjusting means for adjusting said nominal flow rate with respect to said actual flow rate, by controlling the control means. The invention also relates to a corresponding thermal conditioning method.