Radial Pressure Cartridge Integrity Testing
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Solution Overview
Problem
Existing methods for testing the mechanical integrity of glass cartridges used for liquid medicaments lack reproducibility and accuracy, often leading to unnecessary discarding of entire batches due to occasional breakage and variations in glass quality.
Innovation Solution
A testing device that applies radially-directed pressure to the cartridge using a squeezable element, which is axially displaced by a plunger and sleeve, ensuring homogeneous stress distribution and preventing contamination from broken fragments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional burst testing methods are used to test glass cartridge integrity, then testing can be performed, but the results lack reproducibility and precision
Solution Approach 1:
The testing device segments the force application process by using a squeezable element that distributes radial pressure through multiple contact points on the cartridge sidewall, rather than applying concentrated force at a single location. This segmentation of stress application achieves more uniform and reproducible testing results.
Solution Approach 2:
The invention transitions from conventional uniaxial compression testing to multidirectional radial pressure application. The squeezable element applies force from multiple directions simultaneously, creating a more comprehensive and reproducible stress state that better simulates real-world conditions and improves measurement precision.
2Difficulty of detecting and measuring
If visual inspection methods are used to detect glass cartridge defects, then contamination can be detected, but subtle defects and microcracks cannot be identified
Solution Approach 1:
The testing device applies controlled radial pressure to induce stress concentrations at defect locations before final failure occurs. This preliminary stress application reveals subtle defects and microcracks that would not be detectable through visual inspection alone, enabling early identification of potential failure points.
Solution Approach 2:
The invention replaces visual inspection methods with mechanical stress-based detection. By applying controlled radial pressure and monitoring the cartridge response, the system can detect subtle defects and microcracks through mechanical behavior rather than optical observation, significantly improving defect sensitivity.
3Reliability
If entire batches are discarded due to occasional cartridge breakage, then quality control is maintained, but production efficiency and cost are reduced
Solution Approach 1:
The testing device performs preliminary integrity testing on individual cartridges before they are assembled into batches or used in production. By identifying and isolating defective cartridges early through controlled radial pressure testing, the system prevents batch-wide contamination and eliminates the need to discard entire batches, thereby maintaining quality control while preserving production efficiency.
4Difficulty of detecting and measuring
If high radial pressure is applied to detect subtle defects, then detection sensitivity improves, but the risk of causing false breakage increases
Solution Approach 1:
The testing device employs dynamic, controlled pressure application through the squeezable element, gradually increasing radial stress while monitoring cartridge response. This dynamic approach allows detection of subtle defects at lower stress thresholds before reaching levels that would cause false breakage, optimizing the balance between detection sensitivity and sample integrity.
Solution Approach 2:
The system utilizes controlled variation of pressure parameters through the squeezable element's gradual compression. By adjusting the rate and magnitude of radial pressure application, the testing device can optimize detection sensitivity for different defect types while maintaining safety margins that prevent false breakage of sound cartridges.
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
The device provides high reproducibility and precision in testing the mechanical integrity of glass cartridges, allowing for the detection of subtle defects and ensuring the quality of the cartridges before they are used in mass production.
Implementation Method 1
A squeezable element (60) which is radially expandable upon axial compression, is in axial abutment with the distal end (42) of the sleeve (40)
Implementation Method 2
By means of the squeezable element, radially-directed pressure is applicable to the sidewall portion and hence to the breakable item
Data Source
Figure 1
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AI summary
The present invention relates to a testing device for testing the mechanical integrity of a hollow breakable item (70), the testing device comprising: a squeezable element (60) to radially abut with a sidewall portion (77) of the breakable item (70), a sleeve (40) extending in an axial direction (1, 2) to receive the sidewall portion (77) of the breakable item (70), and having a first contact surface (43) to axially engage with the squeezable element (60), a plunger (50) displaceable in axial direction (1, 2) relative to the sleeve (40) and having a second contact surface (53) to axially engage with the squeezable element (60), wherein the squeezable element (60) is axially squeezable by a relative displacement of plunger (50) and sleeve (40) to increase the squeezable element's (60) radial expansion and to apply radially directed pressure to the breakable item's (70) sidewall portion (77).