US3461880A

US3461880A - Filter cigarette

Info

Publication number: US3461880A
Application number: US657842A
Authority: US
Inventors: Thomas A Stubblefield
Original assignee: THOMAS A STUBBLEFIELD
Current assignee: THOMAS A STUBBLEFIELD
Priority date: 1967-08-02
Filing date: 1967-08-02
Publication date: 1969-08-19
Anticipated expiration: 1986-08-19

Description

T. A. sTuZBKBLl-:FIELD 3,4L88O Aug. 19, 1969 FILTER CIGARETTE- 'ruled Aug; 2, 1967"' United States Patent O 3,461,880 FILTER CIGARETTE Thomas A. Stubblefield, P.O. Box 748, Kings Beach, Calif. 95719 Filed Aug. 2, 1967, Ser. No. 657,842 Int. Cl. A24d 1/04; A24c 5/50, 5/52 U.S. Cl. 131-9 17 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the nventon.-This invention relates to the field of filter cigarettes.

Description of the prior art.-Insofar as applicant is aware, the prior art does not include a -ilter cigarette incorporating a filter comprising a closely or densely compacted mass of small-diameter metal fibers, such as steel fibers. In the field of pipe filters, United States Patents 1,535,005 and 1,620,420, each issued to I. M. Wilson for a Tobacco Pipe, disclose the use of commercial steel wool but make no reference to density of compaction or fiber diameter. United States Patent 1,564,500, issued to E. van de Voorde for a Smokers Pipe, discloses a pipe filter comprising a bundle of fine aluminum chips or wire.

SUMMARY OF THE INVENTION In accordance with the present invention, a surprisingly effective filtering action is achieved in a filter cigarette =by use of the densely compacted mass of small-diameter metal fibers, such as steel fibers. Despite the fact that the mass is densely compacted, and the fibers are small in diameter, the draw (or resistance to gas fiow) is not unfavorably affected to any great extent. By using the metal-fiber filter in combination with air-inlet holes which are employed for Ifilter-cooling purposes, and/or in cornbination with another filter material such as activated charcoal, an enhanced filtering action is attained.

DESCRIPTION OF THE DRAWING FIGURE l is a perspective view of a first embodiment of the filter cigarette of the present invention, portions being broken away in order to illustrate the internal components of the cigarette;

FIGURE 2 is a view corresponding to FIGURE 1 but illustrating a second embodiment, wherein air-inlet holes and additional filtering means are provided;

FIGU-RE 3 is a longitudinal central sectional view of the filter end portion of the embodiment of FIGURE 2;

FIGURE 4 is a transverse sectional view taken on line 4-4 of FIGURE 3; and

FIGURES 5-8, inclusive, are fragmentary longitudinal sectiohal views corresponding generally to the showing of FIGURE 3 but illustrating different proportioning of the sizes of the metal-fiber filters in order to adapt the same to the grades of tobacco employed in various cigarettes.

Patented Aug. 19, 1969 lCC DESCRIPTION OF THE EMBODIMENT OF FIGURE 1 Referring to FIGURE 1, the cigarette is illustrated to comprise a tubular wrapper, sheath, casing or jacket 10 which may be termed a wall. The main body 11 of the wrapper or wall 10 is conventionally formed of cigarette paper, whereas the end 12 adapted to be inserted into the mouth may be formed (for example) of real or simulated cork. The end 12 of wall 10 may be termed the mouthpiece. It is to be understood that the entire wrapper or wall 10 (including the mouthpiece) may be formed of paper or the like.

Packed within the wrapper 10, primarily within the paper lportion 11 thereof, is a mass of cut or shredded tobacco 13. Mounted within lthe mouthpiece 12 of the cigarette, in spaced relationship from tobacco 13, is a conventional filter 14 formed, for example, of a suitable cellulosic material. -It is pointed out that the function of filter I4 is primarily aesthetic in that it creates a white appearance at the open end of the cigarette wrapper 10 and, furthermore, does not form any taste in the mouth of the smoker. The illustarted filter 14 has a large number of longitudinally oriented pores or air passages adapted to transmit smoke Without creating excessive impedance to flow thereof. It is to be understood that other types of conventional yfilters 14 may be provided. For example, a plastic element having an X-shaped cross section may be utilized.

Also mounted within the mouthpiece end 12 of wall or Wrapper 10, and located between the tobacco 13 and conventional filter 14, is the filter element 16 which forms the primary component of the present filter cigarette. Filter element 16 is illustrated as being cylindrical in shape and oriented longitudinally of the cigarette, having its outer cylindrical surface in contact with the interior surface of the wall .10. The engagement between the filter element 16 and the interior of wall 10 is sufficiently close that no excessive quantity of smoke may bypass the filter.

As indicated previously in this specification, the filter element 16 is formed of a densely compacted mass of small-diameter metal fibers. The metal may be, for example, carbon steel, stainless steel or aluminum. Preferably, the metal is carbon steel. The metal fibers crisscross each other at random, and at a vast number of 1o cations, but the individual 'fibers lie generally in planes which are transverse (preferably perpendicular) to the longitudinal axis of the cigarette and the filter element 16.

Each of the metal fibers should be small in diameter for the reason that large-diameter metal fibers do not produce highly effective filtering actions. Furthermore, it has been found that even a densely compacted filter formed of very small-diameter metal fibers produces what is termed a good draw, that is to say does not create an excessive impedance to the flow of smoke. When the various metal fibers are small in diameter, there is much more wiping action between the smoke and each fiber as the smoke passes through the filter. Furthermore, there is much more centrifugal throw-out of tars and other particulate substances as the tiny streams of smoke change directions frequently and rapidly while passing through the filter.

It is emphasized that because of the large number of small-diameter passages formed through the densely compacted filter, the smoke increases greatly in velocity as it enters the filter. This improves or enhances the centrifugal and other filtering operations. When the smoke contacts the metal fibers, and particularly Awhen the smoke changes direction in passing through the filter, condensation and centrifugal separation actions are achieved to thus remove particulate matter and other contaminants from the smoke.

The diameter of each fiber should be less than about 0.001 inch. Stated more precisely, it has been found that a very desirable diameter-for each metal fiber is on the order of 0.0002 inch, or 0.0005 inch. Such very fine or small-diameter metal fibers create the vast number of small passages indicated above and desirable in order to achieve the proper filtering action. In a typical filter, having a high density as will be stated below, the number of filter openings is well in excess of one million and may be in excess of several million.

It is emphasized that use of the term diameter is not intended to denote that each fiber is necessarily round, or even square, in cross section. A desirable fiber is rectangular in cross section, being about 0.0002 inch to about 0.0003 inch in thickness, and about 0.0003 inch to about 0.0005 inch in width. Such a fiat or rectangularly cross-sectioned metal fiber is especially effective in trapping particulate matter.

Proceeding next to the very important density factor, applicant has discovered that an extremely effective filter, yet one which does not reduce the draw excessively, results when a compaction pressure on the order of many hundreds of pounds per square inch is applied to a mass of metal fibers of the above-indicated type. Preferably, the compaction pressure is at least one thousand pounds per square inch. As a specific example, when the fibers are steel and have a diameter on the order of 0.0002 inch to 0.0005 inch, as stated above, a highly desirable compaction pressure is on the order of 1,140 pounds per square inch.

The above-specified compaction may be achieved, for example, by mounting a mass of fibers in a tube and then passing a plunger into the tube and pressing the plunger against the fibers at a predetermined pressure (adapted to achieve the above-indicated pounds per square inch).

When the small-diameter metal (for example, carbon steel) fibers are compacted as indicated, there is a surprisingly small amount of springback or rebound after the compaction pressure is removed. Thus, the filter 16 maintains a relatively dense condition as desired. Even such small amount of springback may be reduced by mounting the filter 16 within the wrapper or wall 10 during application of the compaction pressure, and then adhesively securing the wrapper to the external cylindrical surface of the filter 16 prior to removal of the pressure. Other means to maintain maximum compaction pressure, that is to say reduce springback, may be employed.

The length of the lfilter element 16, longitudinally of the cigarette, may be on the order of 0.2 inch to 0.4 inch, for example, although other lengths may be employed. The filter 16 may be provided in one single mass, wad or slug, as shown in FIGURE 1, or various layers of filter wads may be employed.

As stated above, the individual metal fibers should be transverse or perpendicular to the longitudinal axis of the lter cigarette. Furthermore, the small-diameter steel (or other metal) fibers should be so arranged, layer upon layer, that the fibers in adjacent layers lie at angles relative to each other, thus forming a maze or labyrinth. Thereafter, compaction is effected in the manner indicated above.

Laboratory tests have proved that the described filter 16 achieves a surprisingly high degree of reduction in the particulate matter in the cigarette smoke, and also in the nicotine therein. However, the filter does not excessively impede smoke ow (reduce the draw) even after the cigarette has been smoked for a substantial period of time. No substantial clogging action results during the smoking of a cigarette.

The effective filtering action is believed to result from the centrifugal separation of the particulate matter, from the wiping action created by the vast number of smalldiameter metal fibers, and from the cooling (and thus Cil condensing) of the smoke resulting from the action of the heat-conductive metal.

The lengths of the metal fibers are not critical, but may be, for example, on the order of one or two inches.

EMBODIMENT OF FIGURES 2-4 The embodiment of FIGURES 2-4 is, except as specifically stated, identical to the embodiment of FIGURE 1.

In the embodiment of FIGURES 2-4, a mass of activated charcoal 17 is illustrated as located between the metal fiber filter 16 and the conventional filter 14. The charcoal effects adsorption of gases and thereby makes the smoke more mild than would otherwise be the case. The charcoal is preferably formed from peach pits, coconut shells, nut hulls, etc. The activated charcoal filter may also be provided in the embodiment of FIGURE 1.

The second difference between the embodiment of FIGURES 2-4 and that of FIGURE 1 is that air-inlet openings 18 are provided through the wrapper or wall 10 adjacent the filter 16. Such openings should be disposed radially outwardly of the end of filter 16 which is adjacent the tobacco 13, this being preferable to locating the holes elsewhere (for example radially outwardly of the tobacco itself). The purpose of the air-inlet openings 18 is to admit atmospheric air into the filter 16 and thereby cool the same more effectively, in order that a better smoke-condensation effect will be produced.

As the smoker draws or inhales on the end of element 12, the air flows inwardly through openings 18 from the ambient atmosphere, and then passes through filter 16 at regions relatively adjacent the interior surface of the wrapper or wall 10. Thus, particularly the peripheral regions of the filter 16 are directly cooled by the air. It is emphasized, however, that the regions of the filter more near to the center or axis of the cigarette are indirectly cooled by the air due to the effective conduction of heat through the heat-conductive metal fibers.

As a specific example, five air-inlet openings 18 may be provided in uniformly spaced relationship circumferentially of the filter element 16 at the end thereof adjacent tobacco 13. It is pointed out that the end of the filter is indicated at 19 in FIGURES 2 and 3, the openings 18 being adjacent such end but located radially outwardly from filter element 16 instead of from the tobacco 13. However, it is within the broader aspects of the invention to locate the openings radially outwardly from the tobacco 13 but relatively adjacent filter 16.

Each of the five air-inlet openings 18 preferably has a diameter on the order of about 0.010 inch to about 0.015 inch.

The described openings 18 may also be provided in the embodiment of FIGURE 1.

EMBODIMENTS OF FIGURES 5-8 The embodiments of FIGURES 5-8 correspond to the embodiment of FIGURES 2-4 except that the sizing or proportioning of the filter elements is somewhat different. Thus, assuming that the length of the filter element 16 in FIGURES 2 4 is 0.4 inch, that of the filter element 16a in FIGURE 5 is 0.35 inch. Correspondingly, the length of the filter 16b in FIGURE 6 is 0.30 inch; the length of filter 16C in FIGURE 7 is 0.25 inch; and the length of lter 16d in FIGURE 8 is 0.20 inch.

The length of the activated charcoal filter 17 is preferably the same in each cigarette, but the length of the conventional filter 14a, 14b, 14e` or 14d may be increased as illustrated and correspondingly to the diminution in the length of the filter 16a, 16b, 16C or 16d.

The various proportions are illustrated in order to emphasize that the length of the filter 16, 16a, etc., may be varied in accordance with the characteristics of a particular grade, brand or lot of tobacco 13. It is pointed out that the exact dimensions given above are only exemplary, and are primarily for the purpose of showing proportions.

It is one of the features of the present filter cigarette that the taste of the smoke is pleasing to smokers, this being contrary to the taste sensation produced by numerous filters having the object of greatly reducing the inhalation of particulate solids. The taste may be varied somewhat, in the manner illustrated in FIGURES 3 and 5-8, depending upon the grade and type of tobacco and other factors. It is pointed out that menthol, and various other additives, may be provided if desired.

I claim:

1. A filter cigarette, comprising:

an elongated tubular flexible wall element at least a major portion of which is formed of cigarette paper,

a mass of cut tobacco packed into said wall element throughout the majority of the length thereof, and

a filter element mounted in said wall element adjacent one end portion thereof,

said filter element being so related to said wall element and to said tobacco that the smoke resulting from burning of said tobacco will pass through said filter element in response to inhalational drawing upon said one end portion, said filter element comprising a densely compacted mass of small-diameter elongated metal fibers,

said fibers extending transversely to the longitudinal axis of the cigarette, said fibers criss-crossing each other at numerous locations, and in which the said mass of fibers has a density at least as great as that achieved by pressing said mass at a pressure at least on the order of hundreds of pounds per square inch.

2. The invention as claimed in claim 1, in which said metal fibers are selected from the group consisting of carbon steel fibers, stainless steel fibers, and aluminum fibers.

3. The invention as claimed in claim 1, in which said mass of fibers has been compacted under a pressure in excess of 1000 pounds per square inch.

4. The invention as claimed in claim 1, in which the diameters of said fibers are less than about 0.001 inch.

5. The invention as claimed in claim 4, in which said diameters are in the range of about 0.0002 inch to 0.0005 inch.

6. The invention as claimed in claim 1, in which said mass is cylindrical in shape and is on the order of 0.2 inch to 0.4 inch in length.

7. The invention as claimed in claim 1, in which said fibers are oriented generally in planes perpendicular to the axis of said wall element.

8. The invention as claimed in claim 7, in which said fibers in such planes are oriented in mutually crossing relationship whereby to form large numbers of small-size openings through which smoke may pass.

9. The invention as claimed in claim 1, in which airinlet openings are formed in said wall element adjacent said filter element.

10. The invention as claimed in claim 9, in which said openings are adjacent the end of the tobacco section, whereby atmospheric air admitted through said openings in response to drawing upon said one end portion will pass through major portions of said filter element.

11. 'The invention as claimed in claim 1, in which said filter element is cylindrical in shape and is oriented parallel to the axis of said wall element, the length of said filter element being at least several tenths of an inch, the diameters of said fibers being less than one thousandth of an inch, said fibers lying in mutually crossing relationship in planes transverse to the longitudinal axis of said wall element.

-12. The invention as claimed in claim 11, in which said fibers are formed of metal selected from the group consisting of carbon steel, stainless steel and aluminum.

13. The invention as claimed in claim 12, in which said metal is carbon steel.

14. The invention as claimed in claim 1, in which an activated charcoal filter unit is mounted within said wall element adjacent said filter element.

15. The invention as claimed in claim 1, in which said fibers are rectangular in cross section.

16. A smoking device, which comprises:

an elongated tubular wall element,

a mass of out tobacco provided in said wall element,

a filter element mounted in said wall element and so related thereto and to said tobacco that the smoke resulting from burning of said tobacco will pass through said filter element in response to drawing upon the end of said wall element remote from said tobacco,

said filter element comprising a densely compacted mass of small-diameter elongated metal fibers,

said fibers extending transversely to the longitudinal axis of the cigarette, said fibers criss-crossing each other at numerous locations, and, in which said mass of fibers has a density at least as great as that achieved by pressing said mass at a pressure at least on the order of hundreds of pounds per square inch, and

air-inlet means provided in said wall element adjacent said filter element and relatively adjacent said t-obacco, whereby said drawing upon said end will result in passing of air from the ambient atmosphere through said filter element.

17. The invention as claimed in claim 16, in which said air-inlet means comprise a plurality of holes spaced about said wall element, each of said holes having a diameter on the order of about 0.010 inch to about 0.015 inch.

References Cited UNITED STATES PATENTS 1,535,005 4/1925 Wilson 131-261 X 1,564,500 12/1925 Van de Voorde 131-194 1,620,420 3/ 1927 Wilson 131-207 2,210,198 8/ 1940 Blum 131-207 X 2,629,459 2/ 1953 Hammond et al. 3,028,864 4/1962 Munto 131--10.7 3,279,476 10/ 1966 Noznick et al 131-10.7

FOREIGN PATENTS 876,669 9/ 1961 Great Britain. 994,169 6/1965' Great Britain.

MELVIN D. REIN, Primary Examiner U.S. Cl. X.R.