Liquid-Filled Laminate Package Defect Detection Using Wet Electrical Testing
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Solution Overview
Problem
Existing methods for testing the integrity of laminate packages, particularly those without a conductive metal layer, are cumbersome and limited in applicability, requiring disassembly and are not capable of providing continuous or semi-continuous responses regarding package integrity.
Innovation Solution
A method involving a wet testing technique where a package is filled with liquids, an electrode is inserted, and voltage is increased to detect defects by measuring electrical characteristics, allowing for simple and objective assessment of package integrity without disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the package is tested using the red-ink test method, then the test is simple and inexpensive, but the result is merely binary and relies on subjective judgement
Solution Approach 1:
The patent replaces the mechanical/visual red-ink test system with an electrical field-based detection system. Instead of using ink penetration and visual assessment, the invention applies voltage to the liquid inside the package and measures electrical characteristics (current, resistance) to objectively detect defects in the packaging laminate, thereby improving measurement precision while maintaining operational simplicity
Solution Approach 2:
The invention changes the detection parameter from visual ink penetration to electrical characteristics (current, resistance, voltage). By measuring how the package material responds to applied voltage electrically, the system provides continuous quantitative data about package integrity rather than binary visual results, enabling precise quality assessment
2Measurement precision
If the package is deconstructed to attach a ground electrode to the conductive layer, then the ramping voltage test can be performed, but the process becomes cumbersome and risks damaging the inner polymer layer
Solution Approach 1:
The invention extracts the ground electrode attachment step entirely from the testing process. Instead of requiring disassembly to attach electrodes to the conductive layer, the system uses the liquid already present in the package as one electrode and introduces a second electrode through the closure, eliminating the need for package deconstruction and reducing operational complexity
Solution Approach 2:
The invention makes the testing method universally applicable to various package types without requiring specific modifications or disassembly. By using the package closure and existing liquid as part of the testing system, the method can be applied to different package configurations (with or without conductive layers) using the same general procedure, greatly improving ease of operation
3Measurement precision
If the ramping voltage test is used for packages with conductive layers, then continuous response about package integrity is obtained, but the method is limited to certain packaging laminates with conductive layers
Solution Approach 1:
The invention creates a universal testing method that works with all package types regardless of whether they contain conductive layers. By using the liquid inside the package and the closure as electrode interfaces rather than requiring attachment to specific layers, the method becomes adaptable to various packaging materials including those without metal foil, significantly improving versatility
Solution Approach 2:
The invention introduces the liquid and closure as intermediary elements that enable electrical contact without requiring direct access to internal package layers. The liquid serves as an electrical conductor between the applied voltage and the package walls, while the closure provides the interface for electrode insertion, allowing the test to work with any package structure
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
Enables quick and easy detection of defects in packages made from various materials, providing a go/no-go result and continuous assessment of package integrity, including leakage risks and seal quality, suitable for production environments.
Implementation Method 1
A defect in the package is detected by monitoring the voltage or current over time and registering a dielectric breakdown between the supply electrode and the conductive layer of the packaging laminate that is connected to ground
Data Source
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AI summary
An apparatus (10) for detecting a defect (49) in a package (12) that encloses an interior volume (22) configured to hold a liquid food product. The apparatus includes a container (14) arranged to hold a first body of liquid (16) and to receive the package for positioning the package in the container with the first body of liquid surrounding an outer portion (18) of the package. A connector element (20) provides electrical connection to the first body of liquid and an electrode (26) is arranged to be inserted into a second body of liquid (24) contained in the interior volume. A power source (28) feeds an electrical current (29) to the electrode. A control unit (30) (i) controls the power source to increase voltage of the electrode, (ii) measures, with reference to the connector element, an electrical characteristic (U) representing the increased voltage of the electrode, and (iii) determines presence of a defect in the package based on the measured electrical characteristic.