To determine whether the service life of the clean transfer window has expired, it is not sufficient to only consider the duration of use. A comprehensive judgment should be made by taking into account the state of the main structure, the performance of core components, and the compliance of the clean function. The specific judgment criteria are as follows:
Judgment of aging / damage of the main structure
Material corrosion and deformation: Large areas of pitting on the stainless steel frame, weld cracks, or peeling of the paint on the carbon steel spray-painted shell, and penetration of rust through the sheet; cavities show depressions and deformations, which cannot ensure a sealed space, indicating that the structure has expired.
Abnormal operation of doors and windows: Doors and windows are stuck, unable to fully close, or the gap between the door frame and the cavity exceeds 0.5mm, and even after replacing the sealing strips, the problem cannot be improved, requiring a complete replacement.
Failure of core components
Interlock device failure: Mechanical interlock cannot achieve the function of “one door opening, the other door locked”; electronic interlock frequently malfunctions, sensors have no response, and the fault recurs after multiple repairs.
Performance attenuation of high-efficiency filters: The pressure difference of the filter exceeds twice the initial pressure difference, or the particle count in the transfer window exceeds the standard after cleaning, and even after replacing the new filter, it still fails to meet the standard (probably due to failure of cavity sealing).
Faults in the self-cleaning system: The fan of the transfer window makes abnormal sounds, the rotational speed decreases, the self-cleaning time far exceeds the standard requirement (such as 30 minutes of self-cleaning, actually requiring more than 60 minutes), and the repair costs of the motor and duct are too high.
Aging of sealing strips: The sealing strips harden, crack, or fall off. After replacement, they still show poor sealing within a short period of time, indicating that the door frame or cavity has deformed, resulting in the failure of the sealing structure.
Judgment of compliance of clean function
During regular inspections, if the suspended particles and settled bacteria in the transfer window continuously exceed the grade requirements of the corresponding clean room, and after excluding factors such as filters and operational norms, it is determined that the overall performance has expired.
For transfer windows used in sterile environments, if there is persistent microbial contamination that cannot be eliminated (such as bacteria growing in the cavity dead corners), it is considered that the service life has expired.
Additional suggestions
If the usage time of the transfer window has not reached the reference period, but any of the above irreversible faults occur, and the repair cost exceeds 50% of the cost of a new device, it is recommended to directly replace it; if it is only component wear and tear, it can be continued to use by replacing consumables.