Blister Pack Leak Detection Using Flexible Vacuum Bladder
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Solution Overview
Problem
Existing methods for testing the integrity of small semi-rigid, flexible, and multi-cavity blister packages are either destructive, unreliable, or not sensitive enough to detect small defects, as they rely on vacuum decay methods that require ample air, water submersion, or non-contact sensors which can produce false results due to pressure equalization and material deformation.
Innovation Solution
A test chamber with a flexible bladder that adjusts to the package shape, combining vacuum measurements and displacement detection using a proximity sensor or vision camera, along with absolute and differential pressure measurements, to non-destructively identify leaks in blister packages by deflating defective pouches and providing a physical profile for defect verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum decay methods are used to detect leaks in blister packages, then leak detection capability is improved, but the method becomes unreliable for small packages with limited air volume
Solution Approach 1:
A flexible bladder is introduced as an intermediary between the vacuum chamber and the blister package. The bladder transmits vacuum pressure to the package while its own deformation provides a visual indicator of leaks, eliminating the need for sufficient air volume within the package itself for reliable detection
Solution Approach 2:
The system changes the measurement parameter from internal package pressure decay to external bladder deformation. By monitoring how the flexible bladder deforms under vacuum conditions, the system can detect leaks in packages with minimal internal air volume
2Adaptability or versatility
If flexible chamber walls are used to adapt to flexible package area, then adaptability is improved, but the chamber evacuates air from the cavity equalizing pressure before measurements
Solution Approach 1:
The flexible bladder serves as a mediator that decouples the chamber's pressure control function from the package's air containment. The bladder absorbs the pressure equalization effect while still transmitting sufficient vacuum force to indicate leaks through its deformation
Solution Approach 2:
The flexible bladder utilizes a thin film structure that is sufficiently compliant to adapt to package shapes and transmit vacuum pressure, yet maintains enough structural integrity to provide visible deformation indicators without completely equalizing pressure too rapidly
3Reliability
If water submersion testing is used to detect defects, then defect detection capability is improved, but the test becomes destructive and inaccurate
Solution Approach 1:
The patent replaces the water submersion mechanical testing method with a vacuum-based testing approach. Instead of using water and visual bubble observation, the system uses vacuum pressure applied through a flexible bladder, with deformation patterns indicating defects, eliminating the need for water contact and preserving package integrity
4Object-affected harmful factors
If non-contact sensor methods are used to detect defective cavities, then non-destructive testing is achieved, but false measurements occur due to high sensitivity to displacement and pressure equalization
Solution Approach 1:
The flexible bladder acts as an intermediary that amplifies and stabilizes the measurement signal. Instead of directly measuring minute displacements of the package or chamber, the system measures the more pronounced and stable deformation of the bladder, which serves as a reliable indicator of leaks without suffering from the same sensitivity issues
Solution Approach 2:
The system utilizes visual changes in the flexible bladder's shape and profile as the measurement indicator. The bladder's deformation creates distinct visual patterns that are easier to detect and interpret than minute displacement changes, improving measurement precision while maintaining non-destructive testing
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 method allows for accurate and non-destructive detection of leaks in small blister packages of all sizes, independent of package material properties, with high sensitivity and reliability, enabling effective defect location and type identification without causing plastic deformation or false readings.
Implementation Method 1
a vacuum is pulled within the chamber to detect the presence of leaks in seals of pouches formed in a blister package
Implementation Method 2
measuring the absolute and differential pressure of the test chambers
Implementation Method 3
A proximity sensor, vision camera, or ultrasound measurement detects the displacement of the flexible portion of the package
Data Source
AI summary
A method and apparatus for detecting leaks in blister packages wherein a package is supported with a support chamber and a flexible and imperforate bladder is placed over the package after which at least a partial vacuum pressure is applied and a measure made to determine if any leakage is detected while an image of the bladder is detected, such as by a camera, with the image being used to provide a visual indication of the location of a failure in the blister package.