Multilayered textile as/for durable and washable high-performance filtration media and method of assembling thereof

An air-filtration medium for filtering particles in the air, the particles being within a range of particle sizes, the air-filtration medium comprising:

• a first piece of nonwoven textile having a first fiber orientation of predominance, a first structural side and a first fragile-fiber side, the first piece of nonwoven textile being anisotropic and being plastically unstretched;
• and
• a second piece of nonwoven textile having a second fiber orientation of predominance, a second structural side and a second fragile-fiber side, the second piece of nonwoven textile being anisotropic and being plasticly unstretched;
• wherein the first piece of nonwoven textile is superposed to the second piece of nonwoven textile with the first fragile-fiber side facing the second fragile-fiber side and with the first fiber orientation of predominance being non-aligned by at least 10 degrees from the second fiber orientation of predominance, the first and second pieces of non-woven textiles being sealed together along a peripheral edge thereof, thereby defining an enclosure in-between;
• wherein the first fragile-fiber side and the second fragile-fiber side correspond to a side of projected fibers during the manufacturing process of the first and second pieces of non-woven textiles, the first and second fragile-fiber sides having fibers that are more sensible to detachment than fibers on the respective first and second structural fiber sides;
• and
• wherein fibers of the first fragile-side and of the second fragile-fiber side are enclosed in the enclosure.