Determine whether the filter of the VHPpass box exhaust gas treatment device needs to be replaced.

To determine whether the filter of the VHP transfer window exhaust gas treatment device needs to be replaced, the following aspects can be considered:
Judgment of pressure difference
Monitoring method: Pressure sensors are usually installed at the inlet and outlet of the filter. By monitoring the pressure difference between these two points, the clogging condition of the filter can be determined.
Judgment criterion: When the pressure difference reaches or exceeds the threshold specified by the equipment manufacturer, it generally indicates that the filter has been clogged to a certain extent by contaminants and needs to be replaced. The pressure difference threshold of different models of VHP transfer window exhaust gas treatment devices may vary, usually ranging from tens to hundreds of pascals.
Visual inspection
Visual inspection: For some filters with viewing Windows or detachable panels, their appearance can be directly observed. If there is an obvious accumulation of dust or dirt on the surface of the filter, or if the color has significantly darkened, it indicates that the filter has adsorbed a large amount of impurities and may need to be replaced.
Internal inspection: When opening the filter housing for maintenance, check whether the filter paper or filter screen inside the filter is damaged or deformed. If so, it will affect the filtration effect. Even if the pressure difference does not exceed the standard, the filter should be considered for replacement.
Filtration efficiency test
Professional testing: Use professional particle counters and other equipment to test the exhaust gas after passing through the filter and analyze its filtration efficiency for particles of different sizes.
Comparison standard: Compare the detected filtration efficiency with the initial set standard efficiency of the equipment or relevant industry standards. If the filtration efficiency drops significantly, for instance, by 80% to 90% below the initial efficiency, it indicates that the performance of the filter has declined and it needs to be replaced.
Usage time and frequency
Reference manual: Equipment manufacturers usually provide the recommended replacement cycle of the filter in the product manual, which is generally determined based on the usage time or frequency of the equipment. For example, the filter should be replaced after continuous operation for a certain number of hours or after a certain number of disinfection cycles.
Actual situation adjustment: If the usage environment of the VHP transfer window is relatively harsh, such as a high concentration of particulate matter in the surrounding air, or the usage frequency far exceeds the recommendations in the manual, the replacement cycle of the filter should be appropriately shortened. Even if the specified time or frequency has not been reached, it is necessary to consider replacing it in advance.