Sterilizing Unit Edge Wicking Prevention via Temperature Control
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Solution Overview
Problem
Existing sterilizing units for packaging materials face issues with edge wicking due to temperature differences and porosity, leading to inefficiencies and reduced effectiveness of the sterilizing agent, particularly during machine stoppages and startup.
Innovation Solution
Incorporating a countercurrent heat exchanger for preheating the sterilizing agent before it enters the sterilizing chamber and a cooling system to lower the sterilizing agent temperature after production cycles, which helps maintain optimal conditions and prevent degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the machine is stopped and the sterilizing chamber is emptied, then the sterilizing agent is removed from the chamber, but edge wicking still occurs when the machine is restarted due to temperature differences and residual moisture
Solution Approach 1:
The system performs preliminary actions by continuously circulating and temperature-controlling the sterilizing agent even during machine stoppages. The circulation pump keeps the agent moving through the heat exchanger system, maintaining uniform temperature distribution before restart, thereby preventing the temperature gradients that cause edge wicking.
Solution Approach 2:
Temperature sensors continuously monitor the sterilizing agent temperature, and this feedback is used by the control system to adjust heating elements and circulation pump operation. This closed-loop control ensures the temperature remains within the optimal range (70-75°C) even during stoppages, preventing the conditions that lead to edge wicking.
2Productivity
If the sterilizing agent is maintained at high temperature for effective treatment, then sterilization speed is improved, but evaporation and degradation of the sterilizing agent increase
Solution Approach 1:
The system dynamically adjusts the temperature parameter of the sterilizing agent based on operational conditions. During active sterilization, the temperature is maintained at the higher end of the range (73-75°C) for effective treatment. During stoppages or low-demand periods, the temperature is reduced to 60-70°C, significantly reducing evaporation and degradation while maintaining sterilization capability when needed.
Solution Approach 2:
The circulation pump operates continuously to maintain constant movement of the sterilizing agent through the heated zones and storage zones. This continuous circulation prevents stagnant hot spots where evaporation and degradation would be most severe, while ensuring the agent is always ready for immediate effective sterilization when the machine resumes operation.
3Reliability
If the sterilizing chamber is emptied during stoppage, then residual sterilizing agent is removed, but the fibrous material edges retain moisture and cause wicking on restart
Solution Approach 1:
Instead of emptying the chamber during stoppages, the system maintains continuous circulation of the sterilizing agent through the chamber and web material. This continuous action keeps the material edges properly conditioned and prevents the capillary action that causes wicking, allowing the machine to restart immediately without loss of time.
Solution Approach 2:
The system adjusts the temperature parameter during stoppages to a lower range (60-70°C) which reduces the driving force for capillary action and evaporation. This parameter change prevents moisture accumulation at the edges while maintaining sufficient sterilization capability, eliminating the need to empty the chamber and avoiding restart delays.
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 significantly reduces edge wicking and prolongs the effective life of the sterilizing agent by maintaining consistent temperatures and preventing evaporation, ensuring better packaging material integrity and compliance with aseptic standards.
Implementation Method 1
Incorporating a countercurrent heat exchanger for preheating the sterilizing agent before it enters the sterilizing chamber
Implementation Method 2
a cooling system to lower the sterilizing agent temperature after production cycles, which helps maintain optimal conditions and prevent degradation
Implementation Method 3
The web is then fed into an aseptic chamber where the sterilizing agent is evaporated by heating
Data Source
Figure 1
Figure 2~3
AI summary
A unit (1, 1') for sterilizing a web (2) of packaging material for a machine for packaging pourable food products, the unit (1, 1') having a sterilizing chamber (3) containing a liquid sterilizing agent at a first temperature (T1); conveying means (9a, 9b, 9c) for feeding the web (2) through the sterilizing chamber (3) before the web is formed into a succession of sealed packages of pourable food products; a hold tank (11) for the sterilizing agent; feed means (13, 15, 16, 12) activated selectively to feed the sterilizing agent from the tank (11) to the sterilizing chamber (3); drain means (12, 17, 18) activated selectively to drain the sterilizing agent from the sterilizing chamber (3) into the tank (11) in the event of stoppage of the packaging machine; and cooling means (55; 55') activated selectively, at the end of the package production cycle, to cool the sterilizing agent in the tank (11) to a second temperature (T2) lower than the first temperature (T1) . (Figure 1)