US 2754829 A
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United States l atent SMOKE FILTER Howard V. Hess, Beacon, N. Y.
No Drawing. Application February 21, 1950, Serial No. 145,602
13 Claims. (Cl. 131-208) This invention relates to filters and the removal from tobacco smoke of poisons and other constituents that may be either harmful or distasteful to a smoker.
In spite of the recognized and well known disadvantages and objections to smoking, it is nevertheless a habit in which a great many people indulge. It is well known, for example, that tobacco smoke contains various alkaloids and other poisonous materials such as nicotine and also tarry and other constituents which have a highly irritating effect on the mucous membranes of the smoker and frequently leave objectionable deposits in the respiratory system. Other harmful constituents in tobacco smoke include carbon monoxide, ammonia, aldehydes, pyridine bases and pyrrole derivatives.
While there may be disagreement as to the degree of harm which these various constituents do to the smoker, there is no question that smoke containing these constituents is irritating to the mucous membranes, and produces other objectionable physiological effects when drawn into a persons respiratory system.
In fact much effort has been devoted for a long time to find a satisfactory solution to this problem. Various efforts have been made to remove nicotine from tobacco before it is burned, or to remove nicotine and other harmful constituents from the smoke as the tobacco is burned. However, denicotined tobacco is generally considered by smokers to be inferior in taste to untreated tobacco. Numerous filters for pipes and cigarette holders are also used, and a number of brands of cigarettes are sold with filters built into the mouthpiece or into the end of the cigarette to be placed in the mouth; but such filters have not been too effective and at best have only removed a portion of the nicotine from the smoke.
An object of this invention is to provide a tobacco smoke filter in which the filtering material is capable of removing poisons such as nicotine and other harmful con stituents from tobacco smoke in a highly improved and eflicient manner without so altering the smoke as to spoil its taste and appeal to the smoker.
Another object of this invention is to filter the smoke from burning tobacco through an enclosure or chamber containing asubstance that has a large sorption capacity and that removes from the smoke very efiiciently by chemical combination the nicotine and other volatile basic nitrogen compounds therein. 7
A further object is to provide a tobacco smoke filter which imparts a mildness to the smoke by removing selectively harsh irritants and leaving a balanced pleasant smoke.
I have found that it is possible by a simple filtering operation to remove selectively from smoke of burning tobacco the nicotine and other volatile basic nitrogen compounds present in the smoke and to accomplish this result without altering appreciably the taste or odor of the smoke so that its appeal to the smoker is not substantially reduced. This is accomplished by using an ion exchange material in the filter to combine chemically with harmful or objectionable basic constituents in the smoke. More specifically, I have found that nicotine and other basic irritants Will be taken up from smoke passed in contact with a hydrogen exchanging cation exchanger.
Filtering materials that have been used heretofore for tobacco smoke remove constituents from the smoke by a purely physical absorption or adsorption and therefore, at best, remove only a limited proportion of the nicotine and other harmful constituents. Also it is characteristic of such materials to desorb or begin to give off again some of these poisonous materials after the filter material has been in use for a period of time.
I have found that organic cation exchange materials employed in the hydrogen exchanging, or acid regenerated condition are peculiarly effective for removing nicotine, pyridine bases and other volatile basic nitrogen compounds from tobacco smoke. Apparently their effectiveness is due in a large measure to the fact that they combine chemically with nicotine and the other basic compounds in the smoke as well as exert a filtering action by reason of their physical make-up. As contrasted with What I will call physical or mechanical smoke filtering materials, these cation exchangers will remove substantially all of the nicotine from the smoke, and also have a very large capacity for removing nicotine and other volatile basic nitrogen compounds so that they do not lose their ability for removing these materials as quickly as do the materials that have been known and used heretofore for this purpose.
Smoke filtering materials used or proposed heretofore include materials such as special kinds of porous paper, bentonite, molybdic acid and silica gel. At best, however,
even when used in fresh condition, such materials do not remove anywhere near all of the nicotine and similar alkaloid poisons from tobacco smoke passed through them. I have found that as distinguished from such filtering materials, organic hydrogen cation exchangers even when used in a fairly coarse state remove from 97 to 100% of the nicotine contained in ordinary tobacco smoke.
Also, I have found that per unit weight or per unit volume these cation exchange materials are capable of removing nicotine and other volatile basic nitrogen compounds efficiently and selectively from a much larger quantity of tobacco smoke than the previously known physical or mechanical filter materials. These latter materials quickly become saturated and lose their ability to remove harmful constituents from the smoke, thus necessitating either frequent changes of the filtering material if used in cartridge form in some kind of a pipe stem, cigar or cigarette holder, or the use of larger quantities of the filtering material if employed in some kind of built in filter.
It has been mentioned that the filtering materials of my invention take up and hold the nicotine and other constituents removed from the smoke by chemical combination as distinguished from the absorption or adsorption of the physical or mechanical filter materials. This difference is particularly important if the filtering material becomes saturated because silica gel and the like which adsorb the substances removed from the smoke will then begin to desorb or give up to the smoke some of these substances for which they have less aflinity. With my filtering materials desorption does not take place so that after the filter becomes loaded or saturated, the smoke which then passes through the filter simply emerges unchanged.
I have found that any of the organic cation exchange materials which have a reasonably high ion exchange capacity and are capable of being regenerated with acid and used in the hydrogen condition can be employed for filtering tobacco smoke with good results. These products are well known for the conditioning of water and treatment of dilute solutions of chemicals, and are usually wter insoluble synthetic resins containing either sulfonic or carboxylic groups or both that exert chemical'ion exchange activity. it is possible to regenerate them with either a dilute solution of an acid or common salt. The sulfonic group cation exchange resins and sulfonated coal are particularly eitective in accordance with my invention for filtering tobacco smoke and may be used in any suitable manner. I have found that the best results are obtained in filtering smoke if the cation exchange material employed has an exchange capacity of at least 6'kilograins per cubic foot (expressed in terms of CaCO3). While my invention is not limited thereto, I have found that cation exchangers readily available on the market and highly efiective for my purposes include those of the sulfonated coal type and sulfonated resins such as the phenol formaldehyde, polystyrene and polyvinyl type resins. Such materials have been referred to in various publications including Ion Exchange by Nachod, published 1949 by Academic Press, Inc., and Ion Exchange Resins by Kunin and Myers, published 1950 by John Wiley '& Sons, Inc.
Cation exchangers may be manufacture-d in the form of granules or beads and usually are sold in granular form with the particles ranging in size from 16 to 50 mesh. The exchangers may be used in this physical form and simply placed in an enclosure, housing or cartridge of some kind through which the tobacco smoke to be filtered is passed. If desired, these materials may be ground to finer particle sizes and either used alone or mixed with particles of inert or other substances.
A particularly efiicient way of utilizing these exchange materials and one that is made possible by their extremely efficient operation for long periods of time, is by depositing the finely ground material on some kind of a more or less porous carrier. For example, the exchange material may be ground very fine and made up into a slurry which is deposited on layers of fabric, paper or the like where it is allowed to dry. Alternatively, the finely ground exchanger may be mixed with pulp or paper fibers, and this physical mixture dried to produce a light flufiy filtering medium.
The amounts of the cation exchanger used with such carriers, either fibrous or otherwise, may, of course, be varied greatly depending upon the way in which the material is to be used and the amount of nicotine and other basic substances that have to be removed from the smoke.
Smoke filters mode of these exchange materials ordinarily will be discarded after use. However, it is possible to regenerate cation exchange materials by soaking them in a dilute solution of acid such as 3 to solution of hydrochloric or sulfuric acid. After this acid treatment, the resin may be air or force dried and again used for filtering smoke. it will be found that such materials will have as great a capacity for removing nicotine and other volatile basic nitrogen compounds from smoke after such regeneration as they had in their original state.
If the ca ion exchanger to be used as a filter is not already in the hydrogen exchanging condition, it should be treated with a dilute solution of acid and air or force dried as in the procedure for regeneration before it is used in the filter.
There are a great many physical arrangements in which these materials may he used for filtering smoke, most of which are well known and well understood in the art. For example, the granular or finely divided filter material may be packed into removable filter cartridges which are placed in a special chamber in a pipe stem, in a cigarette holder, or in a cigar holder so that the smoke from the burning tobacco is drawn through the cartridge by the smoker. In any case, the exchange material will be held in some form of enclosure or housing whether this be a part of the cigarette, cigar, holder or pipe or a separate removable cartridge.
The exchange material may be used in the filter in a variety of forms. For example, it may be used loose .in the form of finely divided particles, it may be deposited on a porous material such as silica gel, paper plugs, cork or'tobacco, or'it may be deposited on cringled paper or impregnated in such paper or even extruded in the form of fine fibers. The filter material may also be used in the form of an extruded porous plug of the ion exchange resin. As will be apparent to those skilled in the art, the effectiveness of such .material for removing nicotine and other objectionable substances from the smoke depends to a large extent upon the contact between the smoke and the exchange material. Thus, a form that exposes a large surface area of the exchange material for contact with the smoke is particularly effective. The exchange materials in any-of the .above forms may be used in either built-in or removable filters in pipe stems or holders, or maybe used in filters built into the tip or one end of cigarettes, cigars or similar smoking materials as will be well understood by those skilled in the art.
For most purposes a smoke filter containing simply the cation exchange material will be entirely satisfactory. Such a filter will remove selectively the nicotine and other basic irritants from the smoke and impart a mildness to it without dehydrating the smoke or otherwise destroying its appeal to the smoker. High boiling tars and hydrocarbons are also removed to some extent by mechanical filtering and condensing action common to all types of filters.
The terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention, in the use of such terms and expres sions, of excluding any equivalents of the features shown and described or portions thereof, but recognize that various modifications are possible within the scope of the invention claimed.
1. A method of removing poisons from tobacco smoke which comprises passing such smoke in a smoking article in contact with particles of a high capacity organic cation exchange material in the hydrogen exchanging condition.
2. A device for smoking tobacco having therein a tobacco smoke filter which comprises an enclosure through which smoke from burning tobacco is drawn, and finely divided high capacity cation exchange material in said enclosure as a filtering material for removing poisons from the smoke drawn therethrough, said exchange material being in the hydrogen exchanging condition.
3. A built-in cigarette filter containing high capacity acid regenerated cation exchange material as its principal active filtering material.
4. A cartridge for filtering tobacco smoke in a smoking article to remove poisons therefrom which contains high capacity acid regenerated cation exchange material as its principal filtering material.
5. A filter in a smoking pipe which contains as its principal filtering constituent hydrogen exchanging high capacity cation exchange material.
6. A filter for removing poisons from tobacco smoke in a smoking article which comprises cation exchange resin in the hydrogen exchanging condition deposited in dispersed form on a carrier of inert material to expose extensive areas of resin surface to contact with the smoke.
7. A filter for removing poisons from tobacco smoke in a smoking article which comprises finely ground hydrogen exchanging cation exchange resin deposited in dispersed form on paper.
8. A filter for removing poisons from tobacco smoke in a smoking article which comprises finely ground hydrogen exchanging cation exchange resin deposited in dispersed form on paper pulp fibres.
9. A smoking article having therein a tobacco smoke filter which comprises a housing with openings to permit smoke from burning tobacco to be drawn therethrough, and finely divided organic sulfonated cation exchange material in the hydrogen exchanging condition disposed therein so that smoke drawn through the housing passes in direct contact with such material.
10. A smoking article having therein a tobacco smoke filter which comprises a housing with openings to permit smoke from burning tobacco to be drawn therethrough, and finely divided organic carboxylic type cation exchange material in the hydrogen exchanging condition disposed therein so that smoke drawn through the housing passes in direct contact with such material.
11. A smoking article having therein a tobacco smoke filter which comprises a housing with openings to permit smoke from burning tobacco to be drawn therethrough, and finely divided cation exchange resin in the hydrogen exchanging condition disposed therein to filter poisons out of smoke drawn through the housing.
12. A cigarette having a built-in filter at one end thereof for removing poisons from smoke drawn therethrough, said filter containing as its principal active filtering material cation exchange material in the hydrogen exchanging condition.
13. A cigarette having a built-in filter at one end thereof for removing poisons from smoke drawn therethrough, said filter consisting essentially of cation exchange resin in the hydrogen exchanging condition deposited on a carrier of fibrous material.
References Cited in the file of this patent UNITED STATES PATENTS 729,680 Schwartz June 2, 1903 6 Waugh Mar. 1, 1927 Broadway July 19, 1932 Jaeger June 8, 1939 Sutter Sept. 12, 1939 Liebknecht Feb. 20, 1940 Urbain et al Mar. 3, 1942 Frank July 27, 1943 DAlelio Apr. 10, 1945 Dudley Oct. 1, 1946 Luaces Feb. 1, 1946 Monfried Oct. 10, 1950 FOREIGN PATENTS Switzerland Ian. 3, 1950 Great Britain Oct. 30, 1930 Great Britain Dec. 19, 1938 OTHER REFERENCES Chemical Engineering, July 1947, pages 123 to 125,
C. L. Mantell: Adsorption, page 296.
1945, by McGraw-Hill Book C0., Inc., New York, N. Y.