HEPA (High efficiency particulate air Filter), means the filter efficiency reaches 99.97% against 0.3um particle.
Cylindrical HEPA filter is mainly derived from the design of air purifier, because the design of the machine is different from the inlet and outlet surfaces of the panel HEPA filter, so the cylindrical type is adopted. The advantage of cylindrical HEPA filter is relative small resistance, it is suitable for fresh air systems, air purifiers, etc. Which has high requirement on air pressure.