Method, mechanism and apparatus for momentary compression of filter material

A method for wrapping preformed rod-shaped filter segments (S) used in the tobacco industry into a wrapper, wherein the preformed rod-shaped filter segments (S) positioned on the wrapper (103) are travelling on a belt of a conveyor (102), the wrapper (103) being located lengthwise on the conveyor (102), the method characterized by the following steps:

• forming the wrapper (14) into a U-shape,
• momentarily compressing the preformed rod-shaped filter segments (S) by means of at least one rotary compressing member (10) exerting a force (F) on the preformed rod-shaped filter segments (S) located in the U-shaped wrapper (14), the U-shaped wrapper having an edge, wherein the at least one rotary compressing member (10) is situated above the travelling preformed rod-shaped filter segments (S) and the force (F) is directed in a vertical direction (V) or at an angle (β) relative to the vertical direction (V),
• forming the U-shaped wrapper (14) into a cylindrical sleeve around the compressed preformed rod-shaped filter segments (S) by delivering glue from an adhesive applying apparatus on the edge (15) of the U-shaped wrapper (14), yielding a fully closed cylindrical wrapper,
• allowing the compression of the preformed rod-shaped filter segments (S) to cease after the fully closed cylindrical wrapper has been formed, such that space inside the fully closed cylindrical wrapper (14) is filled with at least one preformed rod-shaped filter segment (S).