Static mixer

A static mixer for mixing at least two flowable components, comprising:

• a mixing tube;
• and
• a plurality of mixing chambers disposed within the mixing tube so as to form a plurality of interconnected chamber strings arranged around an axis of the mixing tube, the plurality of mixing chambers including a plurality of basic mixing chambers and at least three modified mixing chambers,
• each basic mixing chamber having a basic structure including at least two side walls oriented substantially parallel to the axis of the mixing tube and at least two end walls oriented substantially transverse to the axis of the mixing tube, each of the side walls having at least one aperture therein, thereby providing passages connecting mixing chambers in different ones of the plurality of chamber strings, each basic mixing chamber having substantially the same length between end walls,
• the modified mixing chambers including a group of three connected chambers each having a shorter length between end walls than each basic mixing chamber and fewer apertures in the side walls than each basic mixing chamber, wherein a first chamber and a second chamber of the group are disposed in a first one of the plurality of chamber strings with the second chamber directly behind the first chamber and a third chamber of the group is disposed in a second one of the plurality of chamber strings with its passages oriented so as to connect the first chamber to the second chamber.