Aerosol Injection Porting for HEPA Filter Testing in Ducts
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Solution Overview
Problem
Testing filter systems, especially in duct systems with limited accessibility or those that do not allow aerosol feeding, poses challenges during certification activities, particularly in environments like remote cleanrooms or those with HEPA filters, where conventional methods fail due to resistance issues.
Innovation Solution
A method and system involving the installation of injection ports and tubing to deliver test media from an accessible location to filters within duct systems, allowing for testing without direct access to the ducts, using components like injection ports, elbows, and nipples to create a path for test media, enabling scanning of filters for functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional aerosol feeding methods are used in duct systems, then filter testing can be performed, but accessibility is required and system resistance becomes problematic
Solution Approach 1:
The patent introduces an intermediary aerosol injection system that delivers test aerosol through a separate injection port and tubing assembly, bypassing the need to feed aerosol through the existing duct system. This mediator approach allows aerosol delivery to the filter without modifying the duct system or requiring accessibility to duct feeding points.
Solution Approach 2:
The invention segments the filter testing function from the duct system by providing a separate aerosol injection pathway. The injection port, tubing, and aerosol generator are separated from the main duct system, allowing independent operation and eliminating the need to access or modify the duct system for testing purposes.
2Reliability
If HEPA filters are installed in existing systems, then filtration is improved, but system resistance increases beyond system capacity
Solution Approach 1:
The patent extracts the aerosol delivery function from the main air handling system by using a separate injection port and tubing assembly. This allows HEPA filters to be installed in the duct system for their primary filtration function without requiring the duct system to provide aerosol for testing, thereby avoiding additional resistance demands on the existing system.
3Reliability
If filter testing is performed in remote cleanrooms, then certification is achieved, but aerosol exposure to non-filtered air is prevented
Solution Approach 1:
The injection port assembly acts as an intermediary that delivers aerosol directly to the filter within the remote cleanroom environment. The sealed connection between the tubing and injection port prevents aerosol from escaping into non-filtered air areas, while still enabling complete filter challenge testing to achieve certification compliance.
Solution Approach 2:
The patent replaces the mechanical approach of feeding aerosol through ducts with a direct injection method using tubing and an injection port. This substitution allows precise control of aerosol delivery directly to the filter face, enabling testing in remote locations without risking aerosol contamination of non-filtered areas.
Data Source
AI summary
Systems and methods are provided for testing filters. In an exemplary embodiment, a method is provided for testing a filter within a duct system that includes mounting a port to a wall of a duct of the system, positioning a section of tubing within the duct from the port until an outlet end of the tubing is disposed adjacent a filter, connecting a source of test media to the port; delivering test media from the source through the port and tubing into the duct to the filter, and scanning the filter for test media.