Metered-Dose Inhaler Test Compartment Pressure Monitoring
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Solution Overview
Problem
Metered-dose-ejection devices, particularly metered-dose inhalers, often suffer from manufacturing tolerances and misassembly issues, leading to inconsistent and unreliable ejection of predetermined doses due to sensitivity to substance nature and ambient conditions in existing assessment methods.
Innovation Solution
A method involving sealingly connecting the ejection outlet of an unaffirmed MDE device to a test compartment, performing an ejection manipulation, and monitoring pressure to affirm if the ejected dose meets predetermined limits, ensuring consistent ejection of rated doses through additional manufacturing and testing steps, including flushing and filtering to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrostatic charge measurement is used to assess MDI dose, then the assessment can be performed, but the measurement accuracy is reduced due to sensitivity to substance nature and ambient conditions
Solution Approach 1:
The patent introduces a test compartment as an intermediary environment between the MDI device and the measurement system. This controlled compartment isolates the electrostatic measurement from ambient conditions (temperature, humidity, air flow) and provides a consistent substance interaction environment, thereby improving measurement accuracy while eliminating sensitivity to external factors
Solution Approach 2:
The test compartment creates an inert, controlled environment for the electrostatic measurement process. By controlling the atmospheric conditions within the compartment and isolating it from the external environment, the measurement becomes insensitive to ambient conditions while maintaining measurement capability
2Ease of manufacture
If MDE devices are manufactured with standard tolerances, then manufacturing is easier, but the ejected dose consistency deteriorates due to manufacturing tolerances and misassembly
Solution Approach 1:
The patent implements self-service through automated testing and sorting. The testing apparatus automatically evaluates each device's ejection performance and the system automatically sorts devices into accept/reject categories, eliminating the need for manual testing and reducing human error while maintaining manufacturing efficiency
Solution Approach 2:
The system provides feedback by measuring the actual ejection performance of each device and using this information to determine acceptance or rejection. This feedback loop ensures that only devices meeting the specified dose consistency criteria are approved, thereby guaranteeing reliability while maintaining ease of manufacture through automated decision-making
3Measurement precision
If additional testing steps are added to affirm rated ejection dose, then dose accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple testing functions into a single integrated apparatus. The test compartment, pressure sensor, electrostatic measurement system, and automated sorting mechanism are combined into one cohesive device, thereby improving measurement precision while avoiding the complexity of multiple separate testing systems
Solution Approach 2:
The testing apparatus is designed with multi-functionality, serving as both the test environment (test compartment), the measurement instrument (pressure and electrostatic sensors), and the sorting system. This universal design achieves high measurement precision without proportionally increasing complexity, as one system performs multiple functions
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
Ensures that MDE devices consistently eject doses within predetermined limits, enhancing the reliability and accuracy of the ejection process by isolating ambient influences and preventing contamination in pressure monitoring.
Implementation Method 1
monitoring pressure in the test compartment after having established a predetermined volume of the test compartment containing the ejected dose of gaseous fluid
Data Source
Figure 1~5
Figure 6
Figure 7
AI summary
For testing metered-dose-ejection devices, whether the ejected dose accords with a rated dose, the device (1) is sealingly applied (26) to a test compartment (24) and upon machine manipulation on the device (M, 5) a dose is ejected into the test compartment (24) Pressure difference established by such injection and with respect to a pre- established reference pressure (30) in the test compartment (24) is monitored by a pressure sensor (32). The output signal (o) of this sensor (32) is indicative of the extent of the addressed dose.