AP247A - Smoking article. - Google Patents

Abstract

A smoking article comprising a rod of smoking material and a filter portion, said filter portion including means for collecting particulate matter in the smoke from the rod of smoking material in a collection zone, and means for heating said collection zone to release the semivolatile compounds whilst allowing the involatiles to be retained in the filter.

Description

This invention relates to a smokiiYgart icle'in' which the smoking material can be tobacco or any other suitable material.

The composition of the cigarette smoke aerosol is complex, containing many compounds in the particulate and vapour phases. It is possible to classify the compounds contained within the particulate phase into two fractions, these are the involatile and semivolatile fractions.

The semivolatile fraction can be defined as consisting of all of those compounds which evaporate from a chemically inert substrate heated to a temperature of 200°C.

Many of the compounds which have been identified as contributors to the taste and flavour of cigarette smoke are contained within the semivolatile fraction. Also it is found experimentally that approximately 50% of the total particulate matter of cigarette smoke is semivolatile.

It is an object of the present invention to deliver to the smoker an enhanced concentration of semivolatile compounds in the smoke and a reduced concentration of involatiles, thus maintaining taste and flavour at lower total· particulate matter yields.

According to the present invention a smoking article comprises a rod of smoking material and a filter portion, said filter portion including means for collecting particulate matter in the smoke from the rod of smoking material in a collection zone, and means for heating said collection zone to release the semivolatile compounds whilst allowing the involatiles to be retained in the filter.

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-2Preferablv the red of smoking material includes a longitudinally extending passage to feed het gases from the tie of the article when lit to the said collection zone. In one creferred embodiment the collection zone is provided by an imrervious transversely extending member on which the particulate matter is deposited by the smoke from the smoking material.

The transversely extending member can be provided by a disc the centre portion cf which provides said collection zone and which is surrounded by an exit opening or openings.

Preferably the disc is provided in a chamber into which smoke from the smoking material is delivered and into which the longitudinally extending passage feeds het cases to the collection zone.

If desired means may be included for accelerating tne hot cases from the cassage into the collection zone, or for accelerating the hot gases from the passage and the smoke into the collection zone.

The means for accelerating the hot gases or hot gases and smoke can include a disc of impervious material having one or more holes within the range of 0.1 to 1.0 mm diameter.

~n another embodiment the collection zone can ce tmo'.'icec m a hich retention filter eleme:—

* C ζ 3 S Ξ Ξ S *3 ΤΓϊβ ZClL-SCwi-On 2 Ο Ω s , λ seconcary inter element can be provided whirr is :ateu at tne mouth niece end of the article.

Preferably the passage in the rod of smoking material .s termed by a lew poresity/permeabilitv tube.

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-3The invention can be performed in various ways but two embodiments will now be described by way of example and with reference to the accompanying drawings in which :

Figure 1 is a cross-sectional side elevation of a smoking article according to the present invention;

Figure 2 is a cross-sectional view on the line II-II in Figure 1;

Figure 3 is a cross-sectional view on the line IIIIII of Figure 1;

Figure 4 is a cross-sectional view on the line IV-IV of Figure 1; and,

Figure 5 is a cross-sectional side elevation of another construction according to the invention.

As shown in Figures 1 to 4 the smoking article according to the invention comprises a rod 1 of smoking material, for example tobacco, carried in a paper outer wrapper 2. The rod is provided with a longitudinally extending passage 3 formed by a tube of low poros ity/'permeability material 4 which may be made from paper or reconstituted tobacco sheet. The tube may have a diameter typically in the range of 0.5 to 5 mm. Also located within the paper wrapper 2 is a filter 5 at the mouth piece end and an impervious transversely extending member in the form of an impaction disc made of material which is temperature stable. Examples of the materials from which the disc may be constructed include metals, for example aluminium, ceramics or plastics such as nylon, polyethylene, polypropylene or cellulose acetate.

Preferably the disc has a low thermal heat capacity and it

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-4may also have a low thermal conductivity, for example when constructed from a ceramic or from Nylon 66. This disc 6 has a central impaction surface 7 which is surrounded by circumferential holes 8 typically of 1 mm diameter.

Between the inner end 9 of the tobacco rod 1 and the surface of the disc 6 a chamber 10 is formed in which is located a second disc 11 which can also be made from a material selected from the examples given for the disc 6, and this may be the same as, or different from, that used in the construction of the disc 6 in a particular construction. One or more (three are shown) small diameter holes 12 are provided in the disc 11 and these may typically be of 0.1 1 mm diameter and preferably 0.4 - 1 mm diameter. These holes act as acceleration nozzles in the manner to be described.

When the article is smoked and the end 13 is lit smoke passes into the chamber 10 and through the nozzles 12, the action of passing through the nozzles 12 increases the velocity of the smoke and assists in the impaction of the smoke against the impaction surface 7 on the disc 6. This causes particulate matter to be deposited in the area 7 and to act as a collection zone.

Hot gases from the burning tip pass down the passage 3, are accelerated through the holes 12 and impact on the surface 7 thus heating the collection zone and deposited particulate matter sufficiently to cause the release of the semivolatile compounds which pass radially outwardly with the smoke and through the openings 8 into the filter 5 and to the smoker. Seme of the semivolatile compounds may be released as they enter the collection zone before impaction due to the heat in the collection zone.

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-5The impaction surface provided by the surface 7 is located typically 2 mm from the nozzles 12. In the embodiment shown the passage 3 is located coaxially with the smoking material rod 1 but it could be displaced to one side if desired.

In the second embodiment as shown in Figure 5 the same reference numerals are used to indicate similar parts as in Figures 1 to 4. In this construction the means for collection of particulate matter in the smoke from the rod of smoking material is provided by a high retention filler element 15. The element 15 is spaced away from the end 9 of the smoking material tod and the filter 15 is located in a chamber 10 in olace of the disc 11. The disc 6 is also dispensed with. In this arrangement smoke from the rod 1 impinges on the front surface 16 of the filter 15 and the filter retains a fraction of the total particulate matter over the first few (ter.) mm of filter material. This is indicated by reference numeral IT. This retained total particulate matter is again heated by hot air or smoke drawn down the passage 3 as in the previous embodiment. The second filter element ; can be spaced away from the filter element 15 as shown or it may abut it. Once again the action of the hot air or smoke heats the deposited particulate matter and releases the semivolatile fractions wricn are then draw- through the filter 5.

.'te seoono zi.ter element z mev nave an inc_usion ot activated carbon tc reduce the concentration of some cf the

If desired ventilation air may be introduced through the wrapper 2 into the filter IT through openings 13 to confine the aerosol and the hot air. smoke stream to the cf CC6 f^; LCSIT

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-6Similarly in the construction shown in Figure 1 ventilation air may be introduced through the wrapper 2 through openings 19 to aerodynamically focus the aerosol onto the disc ό to improve the efficiency of the filter.

If desired ventilation air may also be used to cool the evaporated semivolatiles to facilitate recondensation before delivery to the smoker, for example through openings 22.

Claims (12)

1. A smoking article comprising a rod of smoking material and a filter portion, said filter portion including means for collecting particulate matter in the smoke from the rod of smoking material in a collection zone, characterised by means for heating said collection zone to release the semivolatile compounds whilst allowing the involatiles to be retained in the filter.

2. A smoking article as claimed in claims 1 characterised in that said rod of smoking material includes a longitudinally extending passage to feed hot gases from the tip of the article when lit to the said collection zone.

3. A smoking article as claimed in claim 2 characterised in that said collection zone is provided by an impervious transversely extending member on which the particulate matter is deposited by the smoke from the smoking material.

4. A smoking article as claimed in caim 3 cnaracterised in that said transversely extending member is provided by a disc the centre portion of which provdes said collection zone and which is surrounded by an exit opening or openings.

5. A smoking article as claimed in claim 4 characterised in that said disc s provided in a chamber into which smoke from the smoking material is delivered and into which the longitudinally extending passage feeds hot bad original

AP000247 gases to the collection zone.

6. A smoking article as claimed in claims 1 to 5 characterised by including means for accelerating the hot gases from the passage into the collection zone.

7. A smoking article as claimed in claim 6 characterised by including means for accelerating the hot gases from the passage and the smoke into the collection zone.

8. A smoking article as claimed in claims 6 and claim 7 characterised in that the means for accelerating the hot gases or hot gases and smoke includes a disc of impervious material having one or more holes within the range of

0.1 to 1.0 mm diameter.

9. A smoking article as claimed in claim 2 characterised in that said collection zone is provided in a high retention filter element.

10. A smoking article as claimed in c;a,m 9 characterised in that said high retention filter element is spaced away ‘rom the end of tne smoking material rod to form a chamber adjacent the collection zone and nto which smoke from the smoking material is delivered and into which the longitudinally extending passage feeds hot gases to the collection zone.

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11.

12.

A smoking article as claimed in claims 1 to 10 characterised in that a secondary filter element is located at the mouth piece end of the article.

A smoking article as claimed in claims 1 to 9 characterised in that said passage in the rod of smoking material is formed by a low porositypermeability tube.

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AP000247 jSr&s'»·' o<ABSTRACT

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A smoking article comprising a rod of smoking material and a filter portion, said filter portion including means for collecting particulate matter in the smoke from the rod of smoking material in a collection zone, and means for heating said collection zone to release the semivolatile compounds whilst allowing the involatiles to be retained in the filter.