the warp yarn for a given energy consumption in the vacuum creating mechanism as will be seen in fig8 the positions of baffles 60 and 62 may be adjustable so as to vary the size of slot 68 and clearances 64 and 66 by varying the size of slot 68 and clearances 64 and 66 the velocity of the air drawn from the ambient atmosphere may be varied for a given vacuum within the vacuum chamber as illustrated herein the hollow elongated vacuum chambers adjacent to the picking station may have a round cross section a rectangular cross section or other cross section as desired and as space permits for example the cross section of any of chambers 30 32 34 50 and 53 may be so varied as desired it will also be understood that the means for creating a partial vacuum within the vacuum chambers may be provided for each individual weaving machine with its own individual vacuum pump and motor or the vacuum creating mechanism may be provided at a central station within the weaving room with suitable connections to each of the weaving machines the use of a central collection point makes recovery of the waste material more efficient in any event whether the pneumatic source is provided for individually on the weaving machines or by a central location means are contemplated for turning the vacuum producing means off for individual weaving machines means are provided for closing a suitable damper in the exhaust system when the weaving machine ceases operation for example in exhaust duct 56 when a central collection system is utilized while there is shown and described a preferred embodiment of the invention using specific terms it is to be understood that the invention is not limited.