US 3757802 A
Throw-away filter for cigarettes, cigars, cigarette holders and tobacco pipes, comprising at least in part polystyrene portions having the ability to retain an electrostatic charge. Preferably, the filter comprises two concentric telescopic units, the inner of which consists of polystyrene. The units define plural reversing passages which pass smoke, but tend to trap harmful solids on the electrostatically charged surfaces of the polystyrene portion. The outer unit is tubular and is closed at the upstream end and open at the other. The upstream closure in one instance, comprises a flat flange extending radially outwardly of the tubular portion thereof to space the same inwardly of an outer shell and has smoke passing slots in the peripheral portion of the same. The open end of the outer unit also has smoke passing slots whereby smoke may pass radially inwardly of the filter as it reverses direction, and leaves the filter through the downstream end of the inner unit which is also tubular and open at both ends thereof.
Claims available in
Description (OCR text may contain errors)
United States Patent Streule et al.
1451 Sept. 11,1973
[5 CIGARETTE 0R CIGAR FILTER 2,003,156 5 1935 Robertson 131 212 A  I ento s: Jo S e, e e Gus, Brulis u; 1,658,627 2/1928 Baumann 131/182 Gallen, both of Switzerland 1,104,966 6/1955 France 131/182 6,618 1908 Great Britain 131/212 A [221 F'ledi 1971 643,138 7/1962 ltaly 131 212 A  AppL NW 203,456 1,437,014 3/1966 France 131/212 A Related Applicafiml Primary Examiner-Joseph S. Reich  Continuation-impart of Ser. No. 842,205, July 16, Attorney-Neil F. Markva et a1.
1969, abandoned, which is a division of Ser. No. 613,876, Feb. 3, 1967, abandoned. 57 S R C Throw-away filter for cigarettes, cigars, cigarette hold-  Forelgn Applicatmn Priority Data ers and tobacco pipes, comprising at least in part poly- Feb. 8, Switzerland tyrene portions having the to retain an electro static charge. Preferably, the filter comprises two con- Cl "131/187, 131/212 A, 131/261 centric telescopic units, the inner of which consists of l31/262 131/ polystyrene. The units define plural reversing passages [5 Int-Cl. pass smoke but tend to trap harmful olids on 0' Search A, the electrostaticauy charged urfaces of the polysty- 131/213, 1 262 1 261 187 rene portion. The outer unit is tubular and is closed at 1 the upstream end and open at the: other. The upstream 1 1 References Cited closure in one instance, comprises a flat flange extend- UNITED STATES PATENTS ing radially outwardly of the tubular portion thereof to 491,744 2/1893 Roebel 131 213 x Space the Same inwardly of an and has 851,773 4/1907 Pfortner 131/212 A smoke passing slots in the peripheral portion of the 1,102,865 7/1914 Browne 131/212 A same. The open end of the outer unit also has smoke 1,477,029 12/1923 7 510mm! 4 2 A passing slots whereby smoke may pass radially inwardly 119151414 6/ 1933 y 131/213 of the filter as it reverses direction, and leaves the filter g g? 52 through the downstream end of the inner unit which is o e 3,064,657 [1962 shrinerw 131/262 B X also tubular and open at both ends thereof. 1,064,547 6/1913 Sargent 131/213 3 Claims, 11 Drawing Figures ////1 JZI A T .H' F lsl h] i /l I I Q Q v F s w '1 2 2 2 5 1 e 5 Q V 1 g ,6 \lwfi 2 CIGARETTE OR CIGAR FILTER This application is a continuation-in-part of our copending application SersNo. 842,205, filed July 16, I969, now abandoned, which is a division of our copending application Ser. No. 613,876, filed Feb. 3,
' 1967, now abandoned.
The present invention relates to a filter structure for cigarettes, cigars, cigarette holders and tobacco pipes and particularly to a filter structure of the disposable type.
Cigarette filters are normally produced from materi als having high absorption characteristics such as bleached cotton, cell fibers, paper and the like. In the case of cigarette holders and tobacco pipes, filter cartridges are used which usually comprise a hollow cylinder filled with activated charcoal or similar mineral material.
The filter construction itself frequently comprises a plurality of telescopic or interlocking spaced members which, when assembled, define a smoke passage extending axially of the filter, the smoke being deflected through several l80 turns, so that the smoke will be cooled and at the same time subjected to a distillation process resulting in deposits on the filter surface touched by the smoke and resulting in filtration.
An object of the present invention is to provide a filter with desired characteristics for the retention of noxious and harmful smoke constituents such as nicotine, tobacco tar and the like.
Another object of the invention is to provide a filter which provides means for the retention of the noxious and harmful smoke constituents due to the construction of the filter.
A still further object of the invention is to provide a filter which provides means for the retention of the noxious and harmful smoke constituents due tothe properties of the material from which at least a part of the filter is made.
Referring to the drawings, showing preferred embodiments of the invention:
FIG. 1 is a longitudinal sectional view of a filter made in accordance with the invention; i I
FIG. 2 is a top plan view taken in the direction of arrow II of FIG. 1; I
FIG. 3 is a cross-sectional view taken along the line III-III of FIG. I, the slots-at the upper end of the inner unit being omitted for clarity;
FIG.,4 is a cross-sectional view taken IV-IV of FIG. 1;
FIG. 5 is a longitudinal sectional view of a modified form of the filter shown in FIG. 1; 7
FIG. 6 is another longitudinal sectional view of the filter shown in FIG. 5 with the interior portion of the filter removed;
FIG. 7 is a side elevational view of the inner portion of the filter shown in FIG. 5;
FIG. 8 is a bottom plan view of the inner filter element shown in FIG. 7;
FIG. 9 is a top plan view of the inner filter element shown in FIG. 7;
FIG. I0 is a partial side elevational view of a modification of the inner filter element shown in FIG. 7; and
FIG. I l is a cross-sectional view taken along the line XIXI of FIG. I0. 0
The filter construction shown in FIGS. 1-4 is in the form of a cartridge and comprises a shell 1 partially closed at the bottom end by a disc 2 having a central along the line outlet opening 4. An internal concentric outlet or exhaust tube 5 extends from a position below the top of the shell 1 through the outlet opening 4 in the bottom disc 2. A top disc 3 closes the end of a median tube 6 extending concentrically between the shell 1 and the exhaust tube 5 to the bottom disc 2. The smoke inlet of the filter is formed by a series of radial slots or passages 7 disposed on the periphery of top disc 3, the smoke entering into the exterior intermediate space 8 between the shell 1 and the median tube 6. The slots 7 are very small and are shown oversize in the drawing for clarification. Very fine slot-like passages 7' are formed at the lower end of median tube 6 and still further very fine slotlike passages 7" are provided at the top end of exhaust tube 5.
The smoke entering through slots 7 as noted by arrows a flows downwardly through the exterior intermediate space 8 and then through slots 7 at which point the smoke is deflected through H and flows in the opposite direction through the interior intermediate space 9 between the exhaust tube 5 and the median tube 6. At the upper end of the interior intermediate space 9 the smoke is again deflected vthrough when passing through slots 7 and then flows in the initial direction again through exhaust tube 5 and out of the filter in the direction of arrow b.
At least some of the various elements of the filter construction are composed of polystyrene which has the property of retaining electrostatic charges. At least the top disc 3 and the median tube 6 are formed from polystyrene so that atleast one surface of both the exterior intermediate space 8 and the interior intermediate space 9 may receive and retain an electrostatic charge. The preferred polystyrene which is capable of generating and retaining an electrostatic charge thereon has the following ranges of properties:
TABLE I Yield tensile strength '420-490 kg/cm Yield elongation l.5,-2.5%
upon-34,000 kglem Modulus of elasticity 0.3-0.6 ft lb/in of notch Izod impact strength Softening point 7985 C Hardness, Rockwell M 68-80 Specific gravity l.05-1 .07 Dielectric constant 2.50-2.60 Specific resistance l0"-lt) Ohm-cm Index of refraction 1.59
Polystyrene meeting the above specifications is of the general purpose variety such as that sold under the trade name STYRON 666 by The Dow Chemical Company of Midland, Michigan.
By using polystyrene capable of generating andretaining electrostatic charges in a filter construction and particularly a construction such as that shown in FIG. 1, a substantial increase in the amount of oil-like or greasy deposit has been found to form on the electrostatically charged polystyrene walls of the filter. This unexpected result is caused by the property of polystyrene in generating and retaining an electrostatic charge which facilitates the deposition of nicotine and tar on its surfaces. This in cooperation with the relatively long flow path, the repeated deflection of the various flow paths through the hairfine slots 7, 7' and 7" which act as traps, and the various cooling zones through which the smoke passes all result in substantially increased deposition in the filter. When all the various elements of the filter construction are produced from polystyrene having the ability to generate and retain electrostatic charges, a proportional increase in the amount of nicotine and tar deposition has been found.
The low production cost of the filters makes it possi ble to assemble the filters integral with cigarettes or cigars where they are used only once. In the case of filters 1 used in smoking pipes, they may be discarded and thrown away after they become clogged with impurities. The various parts making up the filter may be easily manufactured at low cost and assembled readily.
A cartridge type filter in many respects similar to the filter found in FIG. 1 is shown in FIGS. 5-9. The shell includes a slightly tapered plug portion 11 for receiving the end of the cigarette or cigar 12. The inlet end of the cartridge includes an annular shoulder 13 which serves as a stop for the end of the cigar or cigarette. An inner exhaust tube 14 secured in an outlet opening in the bottom 21 of the cartridge extends upwardly concentric with the shell 10 to a point short of the annular shoulder 13. A median tube 15 which is sealed at one end by a top disc 16 is inserted through the open end of the cartridge such that the median tube passes downwardly between and a spaced distance from the shell 10 and the inner exhaust tube 14. The top disc 16 has a greater diameter than the median tube 15 forming a circumferentially projecting guide flange 17 which serves to center the tube 15. Although the top disc 16 substantially closes the upper end of the filter, the flange 17 is provided circumferentially with a plurality of slots 18. Similarly the lower edge of the median tube 15 is provided with slots 19. The path followed by the smoke through the filter cartridge is similar to that for the filter shown in FIG. 1. The smoke enters through the slots 18 in the flange 17 as noted by the arrows a. The smoke then passes downwardly between the shell 10 and the median tube 15 and then reverses direction after passing through slots 19. It then passes upwardly between the exhaust tube 14 and the median tube 15 and then again changes direction as it passes over the end of the central exhaust tube 14 and through the outlet as noted by the arrow b.
With this cartridge construction at least the median tube 15 and disc 16 are made of the polystyrene which has the ability of producing and maintaining an electrostatic charge on its surface. Ideally, the whole cartridge however is produced from polystyrene so that all the surfaces which come in contact with the smoke have the ability to attract and deposit tar and nicotine. The cartridge may be easily disassembled for cleaning since the combination median tube 15 and top disc 16 are only loosely retained in position. Thus, when the cigar or cigarette is removed, the disc and tube may be drawn out after which the whole cartridge may be cleaned. Y Y
A modified form of the median tube and top disc is shown in FIGS. 10 and I]. Longitudinal guide ribs 20 are arranged on the outer circumference of the median tuhe l5 so that the coaxial positioning of the median tube I5 within the shell 10 may be assured.
An advantage of the filter cartridge shown in FIGS. 5-9 is that it offers not only a large surface area which is electrostatically charged, but also the large surface area permits a substantial amount of condensed water to coat these surfaces which further enhance the precipitation of nicotine and tar.
While the invention has been illustrated and described herein in its preferred forms, it is to be understood that it may be used in other forms, embodiments and modifications without departing from the spirit thereof.
1. A filter for cigarettes, cigarette holders, cigars, and tobacco pipes, comprising a. a first unit comprising an elongated outer tubular shell with outer and inner side walls and a closure at one end, and an inner, open-ended elongated tube extending through a substantial portion of said outer tubular shell and through said closure, the outer side wall of said inner tube being spaced from the inner wall of said outer tubular shell;
b. a second unit comprising an inner and outer walled median elongated tube axially slidably positioned telescopically in spaced relationship between the inner side wall of said outer tubular shell and the outer side wall of said inner tube, said second unit having an open end at least slightly spaced inwardly in an axial direction from the closure of said outer tubular shell and a, closure at the opposite end thereof, said opposite end of the median tube being spaced inwardly in an axial direction with respect to the open end of said inner tube, said second unit being formed from electrostatically charged polystyrene;
c. the end of said median tube having a closure including an annular lip extending radially outwardly of the outer wall of said median tube and adapted to hold the walls of said median tube spaced from the innerwall of said outer tubular shell and the outer wall of said inner tube;
. means on said lip providing a plurality of relatively fine passages opening into the space between said outer tubular shell and said median tube; and
. means on the end of said median tube providing a plurality of relatively fine passages opening into the space between said median tube and said inner tube;
f. the open end of said first unit extending beyond the closed end of said second unit and beingtapered outwardly to receive the'end of a tubular tobacco product. 3
2. A filter according to claim 1 wherein the means providing the relative fine passages of said median tube and said disc are means providing hair-fine slots which pass smoke gases but trap smoke-carried solids.
3. A filter according to claim 1 wherein said polystyrene of which said second unit is formed has the following properties:
Yield tensile strength Yield elongation Modulus of elasticity lmd impact strength 420 490 kg/Clti 31,000 34,000 kg/cl'n 0.3 0.6 ft. lb./in. of notch Softening point 79 85 C Hardness, Rockwell M 68 80 Specific gravity l.05 1.07 Dielectric constant 2.50 2.60 Specific resistance l0 l0 Ohm-cm lndex of refraction 1.59.