Static mixer with a bundle of chambered strings

A static mixer comprising:

• a bundle of chambered strings arranged in a tube and oriented in a direction of the tube, the chambered strings comprising a plurality of chambers each extending in the direction of the tube between two closed ends, the plurality of chambers including a plurality of mixing-active chambers and a plurality of re-layering chambers, each mixing-active chamber including first and second mutually adjacent side walls having four alternately disposed passages each providing communication with one of first and second neighboring mixing-active chambers downstream thereof and first and second neighboring mixing-active chambers upstream thereof, the plurality of mixing-active chambers being arranged into at least two sections spaced along the direction of the tube by the re-layering chambers, the re-layering chambers each having first, second and third lateral passages providing communication with neighboring chambers.