Determine whether the medium-efficiency filter of the medical screen HEPA box needs to be replaced.

To determine whether the medium-efficiency filter at the medical screen supply air outlet needs to be replaced, the following aspects can be considered:
Observe the appearance
Dust accumulation condition: Visually inspect the surface of the filter. If there is a large accumulation of dust, or even a distinct dust layer is formed, it indicates that its filtration capacity may have declined and replacement should be considered.
Color change: New filters usually have a uniform color and are relatively white. As they are used, if the color becomes significantly darker or darker, it indicates that they have adsorbed a lot of impurities and may need to be replaced.
Monitor resistance
Using a differential pressure gauge: This is a relatively accurate method. Install differential pressure gauges before and after the filter to monitor the pressure difference changes in real-time. When the pressure difference reaches 1.5 to 2 times the initial pressure difference, it indicates that the resistance of the filter increases, the airflow passing capacity decreases, and it needs to be replaced.
Compare the operating parameters: If the fan frequency and current increase during the operation of the air conditioning system, but the air supply volume does not meet the design requirements, it may be due to the increased resistance of the filter. At this time, the filter needs to be inspected and replacement considered.
Evaluate the purification effect.
Test air quality: Use professional air quality testing equipment to measure the number of dust particles, microbial content, and other indicators in the indoor air. If these indicators exceed the corresponding standards of medical facilities and other factors are excluded, it is very likely that the performance of the filter has declined and it needs to be replaced.
Observe the indoor environment: If there is an unpleasant smell or an increase in dust indoors, or if the patient experiences discomfort due to air quality issues while other ventilation equipment is functioning properly, it should also be considered whether the medium-efficiency filter needs to be replaced.
Reference usage time: Based on the actual usage conditions and experience of the medical facility, set a rough usage time cycle. Under normal circumstances, every 3 to 6 months can be used as a reference. However, if the usage environment is harsh and the usage frequency is high, the cycle should be appropriately shortened, and it should be inspected in advance and considered for replacement.