There as been a rising interest in allergy filters for the home over the last several years. Transport tape 12 may be adjusted to run faster or slower than endless belt 17. An optimal speed differential between transport tape 12 and belt 17 will ensure that the vacuum applied to pockets 16 will draw all, or nearly all, of the free-flowing material 8 off transport tape 12, thereby eliminating the need to refeed or recirculate free-flowing material 8.
Such method can further comprise the step of transferring successive pairs of registering articles from the respective receiving means onto a second conveyor (e.g., into the peripheral flutes of a rotary drum), and the introducing step then preferably comprises inserting cigarette filter rod sections into the spaces between pairs of registering articles on the second conveyor.

It is notable that when the data is normalised to either nicotine or tar levels, smoking article (C3) which operates on the basis of the reverse convention of the invention, (i.e. a smaller filter than its tobacco rod), exhibits worse performance, namely a reduced filtration effect, than the conventional arrangements (Ci) and (C2), which would be expected given the improved filtration effects of a wider filter set out in this disclosure.
21. The apparatus of claim 8, wherein said first conveyor comprises a first rotary drum and said receiving means comprises axially parallel peripheral flutes provided at the periphery of said drum and being at least substantially equidistant from one another, as considered in the circumferential direction of said drum, said second conveyor comprising a second rotary drum having axially parallel peripheral flutes for reception of pairs of coaxial articles, the mutual spacing of neighboring flutes of said first drum being equal to half the mutual spacing of neighboring flutes on said second drum.
Pairs of coaxial cigarettes in alternate flutes are released for transfer into the axially parallel peripheral flutes of a second drum-shaped conveyor by a system of valving elements composed of a stationary valving element in the interior of the first conveyor and a rotary valving element which connects at intervals two axially parallel bores of the stationary valving element with a suction generating device.

The two magazines supply plain cigarettes of unit length into spaced-apart portions of successive flutes of the conveyor so that the gaps between the pairs of coaxial plain cigarettes of unit length are sufficiently wide to allow for insertion of filter plugs of double unit length.
Additionally, some properties of the basic material itself combined with the ambient climate in the manufacturing site (mainly relative air humidity) play an important role in the filter rod,such as the moisture regain.Investigating the triacetin content in filter rods during the manufacturing process are drivenby several reasons.
For example, for a smoking article having a demi slim-sized tobacco rod, a reduced proportion of the smoke stream is in proximity to the outer wrapper of the smoking article than would be the case with a super-slim tobacco rod (circumference approximately 17mm), due to the reduced surface-area to volume ratio of the interior of the cigarette through which the smoke stream passes.