What is the specific working principle of the air shower transfer window?

The working principle of the air shower transfer window is to remove surface contaminants when items are transferred across clean areas through the synergistic effect of "air flow purification + physical isolation", and strictly block the air convection between areas of different cleanliness levels, thereby achieving "clean transfer". Its specific workflow and core mechanism are as follows:
I. Core Design: Double-door interlocking isolation structure
The box body of the air shower transfer window is usually made of stainless steel (corrosion-resistant and easy to clean). The two side doors (respectively connected to the clean area and the non-clean area/low-clean area) are associated through mechanical or electronic interlocking devices to ensure that the two side doors cannot be opened simultaneously. This design physically blocks the direct air circulation between the clean area and the outside, preventing the dusty air from the low-clean area from directly entering the high-clean area, which is the basis for preventing cross-contamination.
Ii. Purification Process: High-speed clean air flow sweeps away contaminants
When the items are placed in the transfer window and one side door is closed, the equipment automatically starts the air shower purification program. The specific steps are as follows:
Airflow generation and filtration
The built-in centrifugal fan sucks in the air inside the box (or air drawn from the clean area), which is then filtered through high-efficiency filters (HEPA/ULPA) - the HEPA filter can remove over 99.97% of 0.3μm particles, and the ULPA filter has a removal rate of 99.999% for 0.12μm particles. Make sure the airflow blown out is "clean air".
High-speed airflow directional purging
The filtered clean air is sprayed out at a high speed of 20-30m/s (close to typhoon wind speed) through nozzles distributed at multiple angles on the inner side of the box (usually 3 to 6 in number, arranged in a ring or matrix pattern), forming a strong air circulation. High-speed airflow can exert "shear force" on the surface of objects, peeling off adhering dust, hair, microorganisms, and other contaminants from the surface.
Pollutant collection and filtration
The blown pollutants move with the airflow and are eventually re-sucked in by the fan and filtered again through the high-efficiency filter. The pollutants are retained in the filter to prevent them from spreading or escaping within the box. The entire air shower process lasts for a preset time (usually 10 to 30 seconds, which can be adjusted as needed).
Iii. Program End: Safely open the other side door
After the air shower time is over, the equipment automatically stops the fan operation. At this time, the interlock device of the other side door is unlocked, and the operator can open the door to take out the purified items. If the air shower process is not completed (such as when the time has not arrived), the other side door will remain locked at all times to ensure that the items must go through the complete purification process before being transferred.
Iv. Auxiliary Functions: Enhance Purification Effect (Optional)
Some air shower transfer Windows will be equipped with additional functions to further enhance cleanliness:
Ultraviolet sterilization: After the air shower or during the transmission gap, turn on the ultraviolet lamp (wavelength 254nm) to use ultraviolet rays to destroy the DNA structure of microorganisms and kill residual bacteria, viruses, etc.
Negative pressure design: By adjusting the parameters of the fan, a slight negative pressure is maintained inside the box to prevent unfiltered air from leaking through the door gap into the clean area.
Timed disinfection: It can be preset to run an automatic program. When there is no item transfer, the air shower or ultraviolet disinfection can be started regularly to keep the box clean.
Summary
The working principle of the air shower transfer window can be summarized as:
"Double-door interlocking blocks the airflow → high-efficiency filtration generates clean air → high-speed airflow sweeps and peels off contaminants → filters retain contaminants → after purification is completed, the other side door is unlocked." Through the combination of "physical isolation + active purification", it not only realizes the cross-area transfer of items but also minimizes the risk of contamination to the greatest extent. It is the core equipment for item transfer in a clean environment.