US3577995A - Filter - Google Patents

Abstract

A tobacco smoke filter element comprising a solid smoke barrier having a smoke passageway extending between a forward end wall and a sidewall wherein the sidewall is covered with a thin smoke impermeable membrane provided with a plurality of orifices so that the smoke passing through the passageway must escape from the orifices. The several orifices direct the smoke radially from the membrane against an impingement surface which may take the form of a smoke impervious sheet material supported by the barrier plug.

Description

United States Patent [72] Inventor JackieL. White Ptafftown,N.C. 211 Appl.No. 24,081 [22] Filed Mar.3l,1970 451 Patented May 11, 1971 [73] Assignee R. J. Reynolds Tobacco Company Winston-Salem, N.C.

541 FILTER 10 Claims, 7 Drawing Figs.

[52] U.S.CI l3l/l0.5, 131/201,131/210,131/212 [51] Int.Cl A24d0l/04, A24f01/08,A24f01/16 [50] FieldofSear-ch 131/10.5,

201,210,261(B),213,218;131/212(A),2l2 I [56] References Cited UNITED STATES PATENTS 459,077 9/1891 Lauhoff 131/201X 603,702 5/1898 Nax 131/211 1,959,245 5/1934 Levells 131/211X 2,515,547 7/1950 Brawner 131/212 2,686,524 8/1954 Kershaw et al. 131/21 1 2,954,787 10/1960 Lebert 131/213X 3,312,227 4/1967 Barnett 131/212X 3,318,316 5/1967 Banderas et al. 13l/212X 3,496,946 2/1970 Griffith 13 l l 0.5 3,512,537 5/1970 Pelletier 131/10.3X FOREIGN PATENTS 20,729 1901 Great Britain 131/201 Primary Examiner-Samuel Koren Assistant ExaminerJohn F. Pitrelli AttorneyPendleton, Neuman, Williams & Anderson FILTER This invention relates to a smoke filter and has for an object the provision of a smoke filter of the multijet impingement type which is particularly suitable for use in cigarettes, cigars, pipes and other smoking articles.

THE PRIOR ART Smoke filters of the impingement type are well known to the art. In these devices the smoke, during puffing of the cigarette or other tobacco article, is drawn through one or more small orifices and caused to impinge at high velocity against a baffle or other impingement surface whereby the solid and liquid particulate material within the smoke is deposited on that surface. Certain of the previously proposed filters have been defic'ient in many respects. Most have a low efficiency under conditions where the pressure drop is low enough to be acceptable to the average smoker. Also, many of these, particularly those of the multi orifice type, are of such a structure that they do not lend themselves to production on present-day highspeed cigarette machines.

FURTHER OBJECTS Accordingly, this invention has for the further object the provision of a cigarette filter which is adapted to be produced in conventional high-speed cigarette-making machines of the type now available.

A further object of this invention is the provision of a cigarette filter of the multijet impingement type which is highly efficient at acceptable pressure drops for removing liquid and particulate material from the cigarette smoke during puffing.

A still further object of this invention is the provision of a combination smoke filter element which is particularly useful in the construction of a filter of this invention.

A still further object of the invention is the provision of a multijet impingement device formed in such a way that careful maintenance of tolerances with respect to the relative position of the various component parts is avoided.

Further and additional objects will appear from the following description, the accompanying drawing and the appended claims.

GENERAL DESCRIPTION In accordance with one embodiment of this invention, a

combination smoke filter element is provided which includes a solid smoke barrier plug adapted to be secured to one end of a tobacco rod or other smoking'article. This plug is provided with opposite end walls, one of which is closed and the other of which has an opening. There is also an opening provided in the sidewall of the plug and a smoke passageway is formed between the two openings. A separate thin membrane of a smoke impervious material is secured to and overlies the sidewall across the opening therein thereby closing off the smoke passageway. However, this membrane is provided with a plurality of small smoke-accelerating orifices whereby substantially all of the smoke passed through the passageway also passes through the orifices. In one embodiment of the invention, the end of the barrier plug containing the opening is the upstream end so that when smoke is drawn through the cigarette containing the element, the smoke flows through the passageway in the plug and escapes at a high velocity through the orifices in the membrane in a radially outwardly direction substantially perpendicular to the axis of the plug. When this element is assembled into a cigarette it is surrounded by a sheet of smoke-impervious material such as tipping paper which is in spaced relationship to the sheet containing the orifices. Thus, the smoke escaping from the orifices impinges against the tipping paper to deposit the wet particulate material, whereafter the smoke escapes rearwardly to the smokers mouth.

The passageway between the end wall and the sidewall may take the form of a bore, groove or slot, or any combination of these, the important feature being that the opening of the passageway adjacent the sidewall be covered with the orifice containing membrane to provide the desired orifices for the multijetunit. Usually it is preferred that the barrier plug be cylindrical in shape and that the thin orifice containing membrane be wrapped around and secured to the external cylindrical surface of the plug in such a manner that the small orifices communicate with the smoke passageway in the plug. The plug may be formed of any suitable plastic material such as polyethylene, polypropylene, polymethylmethacrylate or the like or may be fonned of metal, pressed paper pulp or any other material that is impermeable to smoke. The thin orifice containing membrane is impermeable to smoke and may be formed of any suitable plastic, metal foil, treatment paper, and the like, as will be readily apparent to one skilled in the art.

DESCRIPTION OF THE DRAWINGS For a more complete understanding of this invention, reference will now be made to the drawing in which is shown one specific embodiment:

FIG. I is a side elevational view of a smoke barrier plug comprising one element of the filter suitable for use in a smoking article in accordance with this invention;

FIG. 2 is a right-hand end view of the plug shown in FIG. 1;

FIG. 3 is a sectional view taken along the line 3'-3' of FIG.

FIG. 4 is a longitudinal sectional view taken along the line 4-4 of each of FIGS. 1 and 2;

FIG. 5 is a plan view of a strip of orifice containing sheet material suitable for use with the barrier plug shown in FIGS. 1 to 4;

FIG. 6 is a perspective view of the barrier plug of FIGS. 1 to 4 showing the membrane of FIG. 5 in the process of being assembled on it; and

FIG. 7 is asectional view of the filter end of a cigarette showing the combination filter element of this invention assembled therein.

SPECIFIC DESCRIPTION Referring first to FIG. 7, the combination smoke filter element of this invention is mounted on the downstream end of a conventional tobacco rod 12 and is spaced forwardly of a conventional cellulose fiber (e.g., Estron) filter 14. The filter element is secured in assembled relation to rod 12 and the fiber filter 14 by means of conventional tipping paper 16. The two essential parts of the filter element of this invention comprise the thin membrane 18 shown in FIG. 5 and the barrier plug 20 shown in FIGS. 1 to 4.

The plug 20 constitutes a barrier for the smoke at the downstream end of thecigarette rod 12. The plug includes a forward or upstream end wall 22 and a downstream end wall 24. The upstream end wall is provided with an opening 26 which communicates with a smoke passageway 28 extending through the plug. This plug also has a cylindrical sidewall 30 provided with a pair of large slots 32 which constitute openings in the sidewall also in communication with the smoke passageway 28. The forward or upstream end of the plug is cylindrical in nature and provides a support for the tipping paper 16 when the cigarette is assembled. The body of the plug 20 rearwardly or downstream of the slots 32 is provided with a plurality of integral protuberances 34 which also provide support for the tipping paper 16. These protuberances 34 are arranged circumferentially around the rear section of the plug 20 and define therebetween downstream passageways for the smoke.

As most clearly shown in FIG. 6, the membrane 18 is wrapped around the reduced cylindrical rearward section 30 of the plug 20 and preferably adhesively secured thereto or otherwise laminated therewith in such a manner as to seal the slots 32 and hence the smoke passageway 28 except for a plurality of small acceleration orifices 36 which are provided in the membrane. Thus, in the assembled condition the membrane overlies and conforms and is secured to the outer surface 30 of the rearward portion of the plug 20. The membrane also overlies the slots or openings 32 in the sidewall. Accordingly, when smoke is puffed in the assembled unit, it passes downstream from the tobacco rod 12 into the passageway 28 and escapes through the orifices 36 into an annular passageway 38 between the tipping paper 16 and the orifice membrane 18. When this occurs, the smoke is jetted at high velocity against the impingement surface formed by the inner surface of the smoke-impervious tipping paper and the wet particles contained in the smoke are deposited on that surface. The smoke then passes rearwardly or downstream between the protuberances 34 through the fiber filter 14 and to the mouth of the smoker. While tipping paper is shown as providing the impingement surface for the smoke, it will be appreciated that it may be fonned of a sleeve of any other smoke impervious material such as plastic, metal or the like.

It is preferred that the filter element contain at least small orifices 18 through which the smoke can pass and it is also preferred that the orifice membrane be not more than about 0.01 inch thick. For best results it is further preferred that the distance from the downstream outlet of the orifice to the impingement surface should be within certain specified limits, e.g., between about 0.008 and 0.022 inch. ln the embodiment shown, this distance is determined by the length of the shoulder 40 between the cylindrical forward end and the reduced cylindrical rearward end of the plug 20 and the thickness of the membrane 18. Thus, it is preferred that the radius of the forward section of the plug 20 should be between 0.008 and 0.022 inch greater than the radius of the cylindrical rearward section plus the thickness of the membrane.

It will be appreciated that the plug 20 may be readily formed by conventional injection molding techniques and that the membrane 18 can be readily secured thereto by a suitable adhesive or otherwise by conventional high-speed machinery. The assembled unit can then be attached to a tobacco rod either with or without the cellulose acetate filter 14 by conventional methods. In the embodiment shown the tipping paper constitutes an integral part of the filter after assembly since it provides the impingement surface. This tipping paper is supported by the enlarged forward cylindrical section of the plug, the protuberances 34 and (when used) the cellulose acetate filter 12. The rearward end wall 24 does not have an opening which communicates with the passageway 28 and the forward end wall 22 and the membrane 18 are positioned so that all of the smoke drawn from the tobacco rod is required to pass through the multijet orifices.

While one specific embodiment of this invention has been described in the foregoing, it will be appreciated that other modifications may be made without departing from the spirit and scope of the appended claims.

l'claim:

l. A combination smoke filter element comprising a solid smoke barrier plug having opposite end walls and a sidewall, means in said plug defining a smoke passageway between an opening in one of said end walls and an opening in said sidewall, a separate an independent, one-piece, thin membrane of smoke-impervious material immovably secured to and overlying said sidewall across the opening therein closing off said smoke passageway, and means defining a plurality of small smoke acceleration orifices in that portion of said membrane overlying said sidewall opening whereby substantially all of the smoke passed through said passageway also passes through said orifices.

2. A combination smoke filter element comprising a solid smoke barrier plug having opposite end walls and a substantially cylindrical outer sidewall, means in said plug defining a smoke passageway between an opening in one of said end walls and an opening in said sidewall, a separate and independent, one-piece, thin membrane of smoke-impervious material immovably secured to and overlying and sealed to said sidewall across the opening therein closing off said passageway, and means defining a plurality of small smoke ac celeration orifices of substantially equal cross section in that portion of said membrane over yrng said sidewall opening whereby substantially all of the smoke passed through said passageway also passes through said orifices.

3. A combination smoke filter element comprising a smoke barrier plug having opposite end walls and a substantially cylindrical outer sidewall, means defining a smoke passageway in said plug terminating in openings in one of said end walls and in said sidewall, a separate and independent membrane in the shape of a cylinder of a smoke-impervious material immovably laminated to the surface of said outer sidewall across the opening therein and closing off said passageway, and means defining a plurality of small smoke acceleration orifices in said membrane in communication with said passageway whereby all of the smoke passing through said passageway also passes through said orifices.

4. A combination smoke filter element comprising a substantially cylindrical smoke barrier plug including a rearward section and a forward section having a forward end wall, each of said sections being coaxial and having a substantially cylindrical outer sidewall, the forward section being of greater diameter than the rearward section, means extending through said sections defining a smoke passageway through said plug between an opening in said forward end wall and an opening in the sidewall of said rearward section, a separate thin flexible membrane of smoke-impervious material immovably overlying the opening in the sidewall of said rearward section closing off said passageway, and means defining a plurality of smoke acceleration orifices of substantially equal cross section in said membrane in communication with said passageway whereby substantially all of the smoke passed through said passageway also passes through said orifices.

5. The element recited in claim 4 wherein the thickness of said membrane is less than about 0.01 inch and the radius of the cylindrical forward section is between about 0.008 and 0.022 inch greater than the radius of the cylindrical rearward section plus the thickness of said membrane.

6. A smoking article including a filter of the multijet impingement type in the downstream end thereof which comprises a smoke barrier plug having upstream and downstream end walls and a sidewall, means in said plug including openings in said upstream end wall and said sidewall defining a first passageway, a separate thin flexible membrane of smokeimpervious material immovably overlying said sidewall across said opening therein closing off said first smoke passageway, means defining a plurality of small smoke acceleration orifices in said membrane whereby substantially all of the smoke passing through said first passageway also passes through said orifices in a radially outwardly direction, means defining an impingement surface spaced radially outwardly from said orifices against which smoke impinges during smoking, and means defining a second smoke passageway downstream of said impingement surface through which smoke is withdrawn from the filter during smoking.

7. The smoking article recited in claim 6 wherein the plug is generally cylindrical and the membrane is also in the form of a cylinder laminated to said sidewall over the opening therein.

8. The smoking article recited in claim 6 wherein the thickness of the membrane is less than about 0.0l inch and the distance between each of the orifices and the impingement surface is between about 0.008 and 0.022 inch.

9. The smoking article recited in claim 6 wherein the plug includes a generally cylindrical forward section and a generally cylindrical rearward section of less radius than the former, wherein the smoke passageway terminates in an opening in the sidewall of the rearward section, and wherein a separate smoke-impervious sheet supported by the forward section provides said impingement surface.

10. The smoking article recited in claim 9 wherein the rearward section includes radially outwardly extending protuberances spaced rearwardly of said orifices for further supporting the sheet providing the impingement surface.

Patent No. 3,577,995 Dated May 11, 1971 Inventor(s) Jackie t It is certified and that said Letters that error appears in the above-identified patent Patent are hereby corrected as shown below:

Column 2, line 13,

"treatment" should read treated Column 3, claim I, line 57,

change "an" to and Signed and sealed this 1 7th day of August 1 971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Gfi'icer Commissioner of Patents

Claims (10)

1. A combination smoke filter element comprising a solid smoke barrier plug having opposite end walls and a sidewall, means in said plug defining a smoke passageway between an opening in one of said end walls and an opening in said sidewall, a separate an independent, one-piece, thin membrane of smoke-impervious material immovably secured to and overlying said sidewall across the opening therein closing off said smoke passageway, and means defining a plurality of small smoke acceleration orifices in that portion of said membrane overlying said sidewall opening whereby substantially all of the smoke passed through said passageway also passes through said orifices.

2. A combination smoke filter element comprising a solid smoke barrier plug having opposite end walls and a substantially cylindrical outer sidewall, means in said plug defining a smoke passageway between an opening in one of said end walls and an opening in said sidewall, a separate and independent, one-piece, thin membrane of smoke-impervious material immovably secured to and overlying and sealed to said sidewall across the opening therein closing off said passageway, and means defining a plurality of small smoke acceleration orifices of substantially equal cross section in that portion of said membrane overlying said sidewall opening whereby substantially all of the smoke passed through said passageway also passes through said orifices.

3. A combination smoke filter element comprising a smoke barrier plug having opposite end walls and a substantially cylindrical outer sidewall, means defining a smoke passageway in said plug terminating in openings in one of said end walls and in said sidewall, a separate and independent membrane in the shape of a cylinder of a smoke-impervious material immovably laminated to the surface of said outer sidewall across the opening therein and closing off said passageway, and means defining a plurality of small smoke acceleration orifices in said membrane in communication with said passageway whereby all of the smoke passing through said passageway also passes through said orifices.

4. A combination smoke filter element comprising a substantially cylindrical smoke barrier plug including a rearward section and a forward section having a forward end wall, each of said sections being coaxial and having a substantially cylindrical outer sidewall, the forward section being of greater diameter than the rearward section, means extending through said sections defining a smoke passageway through said plug between an opening in said forward end wall and an opening in the sidewall of said rearward section, a separate thin flexible membrane of smoke-impervious material immovably overlying the opening in the sidewall of said rearward section closing off said passageway, and means defining a plurality of smoke acceleration orifices of substantially equal cross section in said membrane in communication with said passageway whereby substantially all of the smoke passed through said passageway also passes through said orifices.

5. The element recited in claim 4 wherein the thickness of said membrane is less than about 0.01 inch and the radius of the cylindrical forward section is between about 0.008 and 0.022 inch greater than the radius of the cylindrical rearward section plus the thickness of said membrane.

6. A smoking article including a filter of the multijet impingement type in the downstream end thereof which comprises a smoke barrier plug having upstream and downstream end walls and a sidewall, means in said plug including openings in said upstream end wall and said sidewall defining a first passageway, a separate thin flexible membrane of smoke-impervious material immovably overlying said sidewall across said opening therein closing off said first smoke passageway, means defining a plurality of small smoke acceleration orifices in said membrane whereby substantially all of the smoke passing through said first passageway Also passes through said orifices in a radially outwardly direction, means defining an impingement surface spaced radially outwardly from said orifices against which smoke impinges during smoking, and means defining a second smoke passageway downstream of said impingement surface through which smoke is withdrawn from the filter during smoking.

7. The smoking article recited in claim 6 wherein the plug is generally cylindrical and the membrane is also in the form of a cylinder laminated to said sidewall over the opening therein.

8. The smoking article recited in claim 6 wherein the thickness of the membrane is less than about 0.01 inch and the distance between each of the orifices and the impingement surface is between about 0.008 and 0.022 inch.

9. The smoking article recited in claim 6 wherein the plug includes a generally cylindrical forward section and a generally cylindrical rearward section of less radius than the former, wherein the smoke passageway terminates in an opening in the sidewall of the rearward section, and wherein a separate smoke-impervious sheet supported by the forward section provides said impingement surface.

10. The smoking article recited in claim 9 wherein the rearward section includes radially outwardly extending protuberances spaced rearwardly of said orifices for further supporting the sheet providing the impingement surface.

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