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.
3 is a fragmentary axial sectional view of the first conveyor 12 of the apparatus 2. It will be noted that the disc-shaped sealing member 18 seals the left-hand end portions of the flutes 13, that the right-hand end portions of the flutes 13 are open, and that the open acetate filter outer sides 13f flutes 13 are at least substantially sealed by the inner side of the shroud 16 in the region where the shroud overlies the peripheral surface of the conveyor 12, namely, between the channel 9 and the transfer station between the conveyors 12 and 17.

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.
The ADFs are devised separately using rods of circular, hexagonal and square shape in square lattice PC. For various values of rod's cross sectional dimension and shape, the resonant wavelength, coupling efficiency, dropping efficiency, Q factor and passband width of the designed filters are investigated through simulation.
15. The apparatus of claim 8, wherein said receiving means are elongated flutes each of which has a length at least matching the combined length of two articles and a filter rod section, each article which assumes said first position being adjacent to one end of the respective flute and each article which assumes said second position being nearer to the other end of the respective flute.

Adjustment of the relative speed differences between the transport tape and the continuous belt carrying the pockets serves to significantly enhance the uptake of the free-flowing material by the pockets and results in essentially none of the free-flowing material remaining on the transport tape.
The continuous belt then carries the pockets, each containing a measured amount of free-flowing material held under vacuum, to a point where the belt begins a course parallel with and adjacent to a travelling garniture tape, such that the pockets are positioned over the garniture tape.
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.