The embedded transfer window is a device installed in the walls of clean rooms, laboratories, hospital operating rooms, and other places that require strict control of environmental cleanliness. It is mainly used to transfer items between areas of different cleanliness grades or between internal and external environments, while minimizing air cross-contamination to the greatest extent. Its working principle revolves around “isolating pollution and achieving efficient purification”, as follows:
I. Core Design: Physical Isolation and Interlock Mechanism
Bidirectional isolation structure
Transfer Windows are usually of box-type structure, embedded in the wall, with doors on both sides (generally made of stainless steel and with good sealing performance), which respectively lead to two areas of different cleanliness grades (such as clean area and non-clean area).
The core of it is the interlocking device: when one side door is opened, the other side door will be locked by mechanical or electronic devices. It cannot be opened simultaneously, thereby preventing direct air convection between the two areas and avoiding contaminants from entering the clean area with the air.
Sealing design
The contact area between the door and the box body is usually equipped with anti-aging and elastic sealing strips to ensure airtightness when the door is closed and further reduce air leakage.
Ii. Purification Process: Remove contaminants from the surface of the items
The transfer window is not merely a “passage”, but a small purification space. Through the built-in purification device, the surface of the transferred items is disinfected or dusted. The specific method is designed according to the scene requirements.
Ultraviolet disinfection (Commonly used)
Ultraviolet germicidal lamps (with a wavelength of 254nm) are installed on the inner side of the box. When items are placed inside and the doors on both sides are closed, the ultraviolet lamps are activated, using ultraviolet rays to destroy the DNA or RNA structure of microorganisms (such as bacteria, viruses, and fungi), thereby achieving the purpose of sterilization and disinfection.
Note: Ultraviolet rays are harmful to human skin and eyes. Therefore, it is designed with interlock protection – when either side door is opened, the ultraviolet lamp will automatically turn off.
High-efficiency Filtration (HEPA/ULPA
Some transfer Windows (such as those used in the electronics and pharmaceutical industries with extremely high cleanliness requirements) are equipped with high-efficiency filters. When the fan is running, the air inside the box is forced to pass through the HEPA/ULPA filter (with a filtration efficiency of ≥99.97% for 0.3μm particles), forming a unidirectional flow (such as vertical laminar flow or horizontal laminar flow), which carries away and filters the dust particles on the surface of the items, maintaining the cleanliness inside the box.
Ozone disinfection (auxiliary
In some special scenarios, ozone generators are used to disinfect items by taking advantage of the strong oxidizing property of ozone. However, ozone should be used in an unattended environment, and after disinfection, it needs to be ventilated for degradation to avoid residue that may affect the human body.
Alcohol spray/wipe (manual assistance)
For high-risk items, operators may first disinfect the surface with alcohol before placing the items in front of the transfer window, and then use the built-in purification function of the transfer window to provide double protection.
Iii. Operating Procedures: Standardized transfer to reduce pollution
Operators in non-clean areas should place items in the transfer window, close this side door, and ensure that the interlock is effective.
Start the purification device (such as ultraviolet lamps or fans) and carry out purification treatment according to the set time (usually 15 to 30 minutes, adjusted according to the disinfection method).
After the purification is completed, the operator in the clean area confirms that the other side door has been unlocked, opens the side door of the clean area, takes out the items, and then closes the door to complete the transfer.
When necessary, the interior of the transfer window can be cleaned regularly (such as wiping the inner wall with disinfectant) to maintain its clean state.
Iv. Application Scenarios: Customized functions on demand
Hospitals: Mainly used for transferring instruments, specimens, etc. between operating rooms and contaminated areas, as well as between laboratories and wards, to prevent cross-infection.
Pharmaceutical/food industry: It is used for the transfer of raw materials and semi-finished products between production workshops and storage areas, as well as between workshops of different cleanliness levels, in compliance with GMP (Good Manufacturing Practice for Pharmaceuticals) requirements.
Electronics/semiconductor industry: Transfer chips, precision components, etc., to prevent contamination by dust particles.
Laboratory: A biosafety laboratory is used to transfer samples and reagents to prevent the spread of pathogenic microorganisms.
Summary
The embedded transfer window, through a dual mechanism of “physical isolation (interlock + sealing) + active purification (disinfection/filtration)”, not only enables the cross-regional transfer of items but also maximizes the cutting off of the transmission path of pollutants. It is a key device for ensuring the stability of a clean environment. Its design needs to be customized according to specific cleanliness level requirements (such as ISO 5-8 grades) and types of contaminants (microorganisms, dust, etc.) to ensure a balance between purification efficiency and operational safety.