Passive Filter Change Unit
HEPA / ULPA-Class Secondary Safety Filtration Solution for Critical Processes
Passive Filter Change Unit, is a HEPA / ULPA-class secondary safety filtration system used after the main dust collection system in critical dust collection and process ventilation applications.
It enables safe operation in API, pharmaceutical, chemical, biotechnology and sensitive manufacturing processes requiring high containment through filter integrity, safe filter replacement, ATEX compatibility, DOP/DEHS test ports and a Bag-In / Bag-Out filter-change design.
HEPA / ULPA Filtration
It provides secondary safety filtration with high-efficiency HEPA and ULPA filter elements for critical applications.
OEB 1–5 Containment
It can be configured according to the containment level for highly active substances and sensitive dust processes.
Bag-In / Bag-Out
A Bag-In / Bag-Out filter replacement system can be used for contact-free and safe filter changes.
What Is a Passive Filter Change Unit?
A passive filter change unit is a secondary safety filtration system installed after a dust collection system to retain fine particles remaining in process air using HEPA or ULPA-class filters.
For critical applications, it can be used as a safety filter after the main collector or as an independent multistage passive filtration system. Filter-change safety is especially important in API, pharmaceutical, chemical and high-containment processes.
Key Technical Features
It can be configured for process needs within a 0–40,000 m³/h range.
It can be evaluated for process pressure conditions from -30 to +30 kPa.
High-efficiency HEPA and ULPA-class filter elements can be used.
A configuration meeting ATEX requirements can be implemented with a dissipative filter medium.
A fully welded housing and closed filter replacement system can be applied for OEB 1–5 levels.
Filter condition can be monitored with a differential-pressure gauge, switch or transmitter.
Technical Configuration of a Passive Filter Change Unit
HEPA / ULPA Filter
It operates as a secondary safety filter in critical processes using high-efficiency filter elements.
Differential Pressure Monitoring
Filter loading can be monitored with a differential-pressure indicator, switch or transmitter.
DOP / DEHS Test Ports
DOP / DEHS measurement checks can be performed through test ports for filter integrity testing.
Closed Filter Replacement
The Bag-In / Bag-Out system can reduce contact and dust release during filter replacement.
System Features
Secondary Safety Filtration
It can be used as a single-stage safety filter after the main dust collection unit. In critical applications, it enables a second check of process air.
Multistage Passive Filtration
For processes requiring independent passive filtration, HEPA and ULPA filter elements can be configured in multiple stages.
Hygienic Stainless-Steel Housing
The stainless-steel housing can be manufactured with advanced hygienic surface treatments, including different finishes and mirror polishing.
WIP Integration
Optional WIP connections can support wet cleaning or pre-decontamination needs before filter replacement and maintenance.
Containment and Safe Filter Replacement
In processes involving highly active substances, operator exposure and environmental contamination must be controlled during filter replacement. A passive filter change unit can be designed to meet containment requirements with a fully welded housing and Bag-In / Bag-Out filter replacement.
ATEX and Filter Safety
In critical processes with combustible dust, HEPA / ULPA safety filters must be assessed not only for filtration efficiency, but also for electrostatic charging, dissipative media use, the dust MIE value, explosion class and hybrid-mixture risk.
A filter medium that provides electrostatic charge dissipation in line with ATEX requirements can be used.
MIE > 3 mJ and different explosibility classes should be analyzed on a process-specific basis.
Processes involving dust and solvent vapour require a dedicated risk assessment.
Filter Testing and Monitoring Options
In critical processes, verifying filter integrity and monitoring filter loading are important for system reliability. Therefore, passive filter change units can incorporate test ports and differential-pressure monitoring equipment.
Applications
Key Considerations When Selecting a Passive Filter Change Unit
Filter Class and Number of Stages
The HEPA or ULPA filter class should be determined according to the need for single-stage or multistage passive filtration.
Containment Requirement
The OEB level, operator exposure limit, Bag-In / Bag-Out need and WIP requirement must be considered in the design.
Pressure and Testing Requirements
Process pressure, differential-pressure monitoring, DOP/DEHS test ports and automation integration should be specified during the project stage.
Operational Advantages
Get Information About a Passive Filter Change Unit
The selection of a passive filter change unit should be assessed for each project according to airflow, process pressure, HEPA / ULPA filter class, OEB containment level, ATEX requirements, Bag-In / Bag-Out needs, WIP connection, DOP / DEHS test ports and hygienic surface requirements.
Request a technical assessment for HEPA / ULPA passive filtration, safe filter replacement and containment solutions.
