Particle control method
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Solution Overview
Problem
In clean environments like RABS and isolator devices, extremely small particles and bacteria descend on the laminar flow, making it difficult to maintain a sterile state, especially when using general-purpose filing devices and containers with various shapes, and current monitoring methods are inefficient in capturing these particles across the entire clean zone.
Innovation Solution
The implementation of an oscillation board subjected to ultrasonic vibration in the clean zone to control the movement of particles by generating acoustic flows or standing waves, guiding particles away from sensitive areas such as container openings or particle counters, allowing for precise control of particle descent and efficient capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a laminar flow is used to maintain a clean zone, then dust-free and sterile state is improved, but particles and bacteria still descend on the stream and contaminate containers
Solution Approach 1:
The patent applies ultrasonic vibration to the oscillation board to generate acoustic waves that create acoustic radiation pressure. This mechanical vibration mechanism prevents particles from descending into containers by creating upward acoustic forces that counteract gravity and laminar flow descent, thereby maintaining sterile conditions without compromising the laminar flow system.
Solution Approach 2:
The patent changes the physical state of the oscillation board from static to dynamically vibrating at ultrasonic frequencies. By adjusting vibration parameters such as frequency and amplitude, the system controls acoustic radiation pressure to dynamically prevent particle descent, transforming the approach from passive laminar flow reliance to active acoustic field control.
2Reliability
If Grade A clean zone is maintained with laminar flow, then dust-free guarantee is improved, but particles up to 3520 particles/m3 still exist and descend to lower areas
Solution Approach 1:
The patent converts the harmful gravitational descent of particles into a beneficial controlled distribution pattern. By using ultrasonic vibration to create acoustic radiation pressure, particles that would naturally descend are instead redirected to accumulate in specific safe zones away from container openings, transforming the harmful effect of particle presence into a controlled and manageable situation.
3Reliability
If strict access restriction and sealed chamber are used, then sterile state is improved, but particle monitoring and control across the entire zone becomes difficult
Solution Approach 1:
The oscillation board acts as an intermediary device between the laminar flow system and particle control objectives. By introducing this acoustic field mediator, the system achieves both sterile state maintenance and improved particle detectability, as the acoustic waves interact with particles to enhance their detectability while maintaining the sealed chamber environment.
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 effectively prevents particles from mixing with pharmaceutical products and ensures accurate monitoring of the clean zone's cleanliness by guiding particles to specific positions, such as container openings or particle counters, enhancing the sterile state maintenance and measurement efficiency.
Implementation Method 1
an oscillation board, the surface thereof is disposed substantially in parallel with a flow direction of the unidirectional air flow in a clean zone is subjected to ultrasonic vibration
Implementation Method 2
the ultrasonic wave is made to act on particles made to flow by the air in the unidirectional air flow and descending from the upper side toward the lower side so that the descent position is controlled
Data Source
AI summary
A particle control method is provided which can prevent an extremely small quantity of particles descending on a stream of a laminar flow in a clean zone through which the laminar flow flows as in a RABS or isolator device from descending to a specific position or can guide it so as to descend to the specific position by controlling movement of the particles. A particle descent position is separated away from a board surface of the oscillation board by using an acoustic radiation pressure generated by prompting ultrasonic vibration of the oscillation board disposed with a board surface substantially in parallel with a flow direction of the laminar flow.