Abstract

For the purpose of producing a cigarette filter unit provided with chambers which are filled with a pourable filter material a filter rope provided with chambers having filling openings which terminate to the outside is conveyed past a filler member provided with a filler opening lying sealingly against the latter. In order to obtain satisfactorily filled chambers even at very high advance speeds of the filter rope, the interior of the first chamber of the filler member which interior is connected to the filler opening is maintained during the filling process at an internal pressure which lies above that of the surrounding atmosphere. When then the chambers to be filled come into connection with the filler opening of the filler member an air stream is effected which, in consequence of the pressure difference thus produced, is directed out of the filler member into the chambers to be filled and which conveys filter material out of the filler member into the chambers to be filled of the filter rope. In order to be able to replenish the first chamber without substantial alteration of the internal pressure P1 prevailing therein, with pourable filter material, a second pressure chamber is provided as pressure gate, which chamber is connected to the first pressure chamber and is closable relatively to the outer atmosphere PA by means of a second closing arrangement, so that the second chamber in turn can be replenished with pourable filter material from the outside without influence upon the internal pressure P1 prevailing in the first chamber.