WO2003037115A1

WO2003037115A1 - Reed valve controlled canister

Info

Publication number: WO2003037115A1
Application number: PCT/US2002/033940
Authority: WO
Inventors: Martin T. Garthaffner
Original assignee: Philip Morris Products S.A.
Priority date: 2001-10-30
Filing date: 2002-10-23
Publication date: 2003-05-08
Also published as: US20040237976A1

Abstract

A smoking article such as a cigarette (10) comprises a tobacco rod (12) and a filter assembly (14) that includes an impervious sealed canister (18) at least partially filled with an active medium (20) for modifying the characteristics of mainstream tobacco smoke. Placement of the active medium (20) in the sealed canister (18) maintains its freshness and activity level over extended periods of time. Valve structure (30, 32) on opposite ends of the canister (18) have normally closed positions for sealing the active medium (20) within the impervious canister (18). The valve structures (30, 32) also have open positions upon the application of draw upon the cigarette (10) so that mainstream smoke generated by the tobacco rod (12) when lighted passes through the open valve structures (30, 32) and the active medium (20) within the canister (18). The active medium (20) inside the canister (18) may be activated carbon for removing selected constituents from mainstream tobacco smoke and/or flavor enhancing compositions for imparting flavors to the smoke, for example.

Description

REED VALVE CONTROLLED CANISTER Background of the Invention

The present invention relates to the improved delivery of additive materials to smoking articles. More particularly, this invention relates to providing additive materials in sealed canisters that are opened during use to modify the characteristics of smoking articles such as to remove selected smoke constituents and/or add flavor to the smoke.

It is known to provide a smoking article with additive materials to modify the characteristics of the smoking article. Additive materials typically modify the characteristics of the smoking article by passing gases, more particularly the gaseous by-products of combustion, through the portion of the smoking article containing the additive material.

For example, sodium and/or calcium permanganate Ca(MnO₄)₂ or NaMnO₄ with colloidal silica deposited onto silica gel or alumina has been incorporated into filter elements to reduce smoke components such as NO, HCN, etc., as are disclosed in U.S. Pat. Nos. 3,957,059 and 4,637,408, incorporated herein by reference. Menthol and other flavorants deposited on carbon, silica, and other activated particles in the filter section of a smoking article have been used to impart a flavor or taste to the smoking article.

One of the problems with adding additive materials to smoking articles is that the active agents of the additive materials deactivate or volatize with time so that they do not have the desired effect at the time of smoking. Further, flavorant materials may be extensively trapped by components of the smoking articles so that less then desired amounts are delivered to the smoker. For example, a significant amount of menthol is trapped on active carbon or in cellulose acetate fibers of a conventional cigarette. Adding excess additive materials to compensate for expected loss of activity or entrapment results in inconsistent products because of variations in storage time prior to smoking and the conditions under which the article is smoked. The rigorous controls over product storage conditions and shelf life that would be required to minimize the volatility or deactivation of the active agent in the additive material are not commercially practical.

Another problem is that some agents deactivate with the absorption of moisture or other volatile materials during storage or can migrate to the wrapper or embed in the filter or carrier of the smoking article so that they will not modify the smoke characteristics as desired.

A problem with adding additive materials to filter portions of smoking articles is that the filter containing, for example, the carbon activated particles on which menthol is conventionally deposited is closer to the burning end of a smoking article than is desirable, thus resulting in inefficient or unsatisfactory use of or undesired combustion or pyrolysis of the additive.

Accordingly, there is a continuing need to provide for improving the effective and efficient delivery of additive materials for modifying the characteristics of smoking articles under widely varying storage conditions.

Summary of the Invention

It is an object of this invention to provide a canister that contains an additive material for the modification of smoking articles to minimize the loss or degradation in efficacy of the additive material prior to smoking. It is a further object of this invention to provide a canister that contains a smoke modifying additive material in a sealed condition prior to smoking, and which at the time of smoking may opened so as to unseal the active agent to render it available to modify the smoke of the smoking article.

In accordance with the present invention, a smoking article comprises tobacco and a filter component that includes an impervious sealed canister at least partially filled with an active medium such as a medium for removing selected constituents from tobacco smoke and/or a medium for adding flavor, for example. The freshness and activity level of the active medium is maintained until lighting of the smoking article and drawing smoke therefrom. During smoking, the canister is unsealed to thereby expose the active medium therein to the mainstream tobacco smoke generated by the smoking article.

Preferably valve structures on opposite ends of the canister each have a normally closed condition for sealing the active medium within the impervious canister. Additionally, the valve structures each have an opened condition when draw is applied to the smoking article during smoking. With the valve structures in their opened positions, mainstream smoke generated by the tobacco when lighted passes through the valves and the active medium within the canister.

Each valve structure may comprise a reed valve having a normally closed condition. When vacuum is applied to these reed valves during drawing upon the smoking article, each reed valve is pulled or otherwise deflected downstream which opens the valves thereby allowing mainstream smoke to pass into and out of the canister and through the active medium therein. The active medium may comprise activated carbon for removing selected constituents from mainstream tobacco smoke. Also, other active mediums may be filled into the canister such as flavorants for imparting flavor to mainstream tobacco smoke, for example.

Brief Description of the Drawings

Novel features and advantages of the present invention in addition to those mentioned above will become apparent from a reading of the following detailed description in conjunction with the accompanying drawings wherein similar reference characters refer to similar parts and in which:

Figure 1 is a side elevational view of a cigarette with an impervious sealed canister containing an active medium for modifying the characteristics of mainstream tobacco smoke, according to the present invention;

Figure 2 is an enlarged longitudinal cross sectional view of the filter end of the cigarette shown in Figure 1 with the valve mechanisms on opposite ends of the canister in their normally closed condition, according to the present invention;

Figure 3 is a right end elevational view of the filter end of the cigarette shown in Figure 2;

Figure 4 is a view similar to Figure 2 but showing the valve mechanisms in their opened condition;

Figure 5 is a right end elevational view of the filter end of the cigarette shown in Figure 4; and

Figure 6 is a view similar to Figures 2 and 4 illustrating an alternate embodiment of the present invention. Detailed Description of the Invention

Referring in more particularity to the drawings, Figure 1 illustrates a cigarette 10 comprising a tobacco rod 12 and a filter assembly 14. Both the tobacco rod and the filter assembly are surrounded by an outer wrap of paper 16. Filter assembly 14 includes an impervious canister 18 at least partially filled with an active medium 20. The active medium may comprise any desired substance for modifying mainstream tobacco smoke, as explained more fully below. For example, activated carbon may be used to remove selected constituents from the tobacco smoke and/or flavorants may be used to impart a desired flavor to the tobacco smoke. Such flavorant enhancing substances may include the flavored threads described in U.S. Pat. No. 4,281 ,671 , incorporated herein by reference.

The impervious canister 18 includes an interior compartment 24 for containing the active medium 20. The compartment includes opposite end walls 26, 28 and these walls are perforated thereby allowing mainstream smoke from tobacco rod 12 to pass through the active medium under certain conditions during smoking.

An upstream reed valve 30 is positioned within the canister 18 slightly spaced from the end wall 26 of compartment 24. Similarly, a downstream reed valve 32 is positioned within the canister 18 slightly spaced from end wall 28 of compartment 24. Each reed valve includes a support plate 34 with a central opening 36. A normally closed flap 38 is positioned directly adjacent to each support plate 34. The flap includes a live hinge line 40 about which the flap articulates. The flap 38 may be formed by a in a U-shaped cut 42 in a disc 44 fixed in place next to support plate 34. Each flap has a normally closed position as shown in Figure 2 where the flaps seal the openings 36 in the support plates 34. However, upon the application of suction generated when drawing on the filter assembly of cigarette 10, the flaps 38 both move in a downstream direction thereby moving away from their associated openings 36 in the support plates 34. This enables mainstream smoke generated by a lighted tobacco rod 12 to pass into the filter assembly through the canister 18. Smoke passes through openings 36 in the support plates 34 and also through the perforated end walls 26, 28 and through the active medium 20. The flaps 38 articulate about the live hinge line 40 upon the application of draw to cigarette 10 but once such draw is terminated by the smoker the flaps return to their normally closed positions. This overall arrangement maintains the freshness and activity level of the active medium 20 which is only exposed to the atmosphere and mainstream tobacco smoke when the cigarette is puffed by the smoker.

Support structure in the form of radiating members 50 is provided for holding the various elements of canister 18 in place. The support structure also functions to space these components in the positions shown in Figures 2 and 4.

Figure 6 illustrates a slightly different embodiment of the canister 18 where a slightly different form and arrangement of support structure 50' is utilized. Otherwise, the arrangement and function of the embodiment of Figure 6 is identical to that shown in Figures 2 - 5, and similar reference characters have been used to identify similar parts.

Any number of different active mediums 18 may be placed within compartment 24 of canister 18. By way of example, activated carbon may be used for removing selected constituents from the mainstream tobacco smoke generated by tobacco rod 12. Alternatively, or additionally, a flavorant within compartment 24 may be used for imparting a particular flavor to the mainstream tobacco smoke as such smoke passes through the canister.

Claims

I CLAIM:

1. A cigarette comprising a tobacco rod and a filter assembly including an impervious canister at least partially filled with an active medium for modifying the characteristics of tobacco smoke, and valve structures on opposite ends of the canister each having a normally closed condition for sealing the active medium within the impervious canister, and the valve structures each having an opened condition upon application of draw on the cigarette whereby mainstream smoke generated by the tobacco rod when lighted passes through the value structures and the active medium within the canister.

2. A cigarette as in claim 1 wherein each valve structures each comprise a reed valve having a normally closed condition.

3. A cigarette as in claim 1 wherein the active medium comprises activated carbon for removing selected constituents from mainstream tobacco smoke.

4 A cigarette as in claim 1 wherein the active medium comprises a flavorant for imparting flavor to mainstream tobacco smoke.

5. A cigarette as in claim 1 wherein the active medium comprises activated carbon for removing selected constituents from mainstream tobacco smoke and a flavorant for imparting flavor to mainstream tobacco smoke.