What is Nominal Pore Size and Absolute Pore Size of Filter Cartridges?

In the filtration field, the accuracy that cannot be completely filtered but can be mostly filtered target accuracy, we call it Nominal Pore Size; and the accuracy that can almost completely filter target accuracy, it is called Absolute Pore Size.

PP Melt blown filter cartridge is made of polypropylene (PP) material, after heating melting, spinning, traction to form tubular filter cartridge. It is gradient structure: high desity internal layer; loose external layer. The loose external layer is for blocking larger size particles; and high desity internal layer is for intercepting fine particles. PP Melt blown filter cartridge is suitable for uneven aperture particle and complex situation. 

From below PP Melt blown filter cartridge fiber structure picture, we can see it display 3D tree structure. It does not have an uniform aperture. Impurities move with liquid and are intercepted when they hit the "fork". There are always some particles escaping being intercepted. It is obviously that the PP Melt blown filter cartridge can not 100% intercept its marked filtration accuracy. That is the reason why there is no absolute pore size on PP Melt blown filter cartridge.

Below is PP Melt blown filter cartridge fiber structure picture: