A Pass Box is a sealed cabinet with interlocked doors, designed for safe material transfer between cleanrooms while preventing contamination. It maintains sterility using UV light, HEPA filters, or airflow systems.
A Pass Box looks like a compact cabinet with two tightly sealed doors on opposite sides. It appears simple but plays a crucial role in controlled environments.
Purpose of a Pass Box
The Pass Box ensures contamination-free material transfer between cleanrooms or sterile zones.
- Prevents cross-contamination by keeping one door locked while the other is open.
- Maintains air purity with filters or UV sterilization.
- Reduces human interference, lowering contamination risks.
Types of Pass Boxes
pass box classifications based on functionality, design & structure, application, and customization.
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By Functionality
A. Interlock Types
- Mechanical Interlock Pass Box– Uses a physical mechanism to block both doors from opening together.
- Electronic Interlock Pass Box (Magnetic Lock) – More reliable, prevents jamming, and stays secure even during power cuts.
B. Self-Cleaning & Purification Features
- Standard Pass Box – Basic UV light and interlock system.
- Self-Cleaning Pass Box – Includes HEPA filters and fans for cleaner air.
- Laminar Flow Pass Box – Provides ISO Class 5 clean airflow in one direction.
- Air Shower Type – Blows dust off materials before entry.
C. Specialized Functions
- Pressure Differential Alarm – Monitors filter performance in pharma labs.
- DOP Test Port Pass Box – Checks HEPA filter efficiency using aerosol tests.
- Multi-Side Sterilization – UV lights on multiple sides for full disinfection.
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By Design & Structure
A. Door Configuration
- Straight-Through (Dual-Door) – Standard for direct transfers.
- Corner-Type – Fits angled walls to save space.
- Three-Door Type – Allows transfers in multiple directions.
B. Material & Build
- Stainless Steel Pass Box – Common in pharma and food industries (easy to clean).
- Powder-Coated Steel Pass Box – Used in electronics (matches cleanroom panels).
C. Installation Methods
- Wall-Mounted Pass Box– Lightweight, fixed to partitions.
- Floor-Standing – Heavy-duty, requires a base frame.
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By Application & Industry
| Industry | Key Needs | Recommended Pass Box |
|---|---|---|
| Electronics | Dust control, ESD-safe | Powder-coated, standard interlock |
| Pharmaceuticals | Sterility, GMP compliance | Stainless steel, HEPA-filtered |
| Hospitals & Labs | Full sterilization | Multi-side UV, laminar airflow |
| Food & Packaging | Hygiene, easy cleaning | Stainless steel, washdown-resistant |
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Custom & Non-Standard Pass Boxes
- Voice Communication Type – Built-in intercom for coordination.
- Roller Conveyor Type – Moves heavy items with minimal handling.
- Pneumatic Lift Door Type – Fast-opening for automated systems.
How Does a Pass Box Work?
Pass Box's functions like an airlock. When one door opens, the other remains locked. Some models incorporate UV light or HEPA filters to sterilize items inside. The interlock system ensures only one side is accessible at a time, keeping contaminants out of controlled areas.
In laminar flow pass boxes, clean air sweeps away particles. In air shower types, high-speed jets remove dust. Advanced models include alarms to monitor air pressure or filter conditions.