EP0014477A1

EP0014477A1 - Method and apparatus for forming filter rod containing particulate material, especially charcoal impregnated filter rod

Info

Publication number: EP0014477A1
Application number: EP80100669A
Authority: EP
Inventors: Reiner G. Brinker
Original assignee: Philip Morris USA Inc
Current assignee: Philip Morris USA Inc
Priority date: 1979-02-12
Filing date: 1980-02-11
Publication date: 1980-08-20
Also published as: AU5528180A

Abstract

A laterally widened, flat travelling web (16) of filter material is advanced beneath a rotary roller applicator (40) which propels granularform charcoal (14) onto the web (16) to impregnate and substantially uniformly distribute the charcoal (14) throughout the web.

Description

BACKGROUND OF THE INVENTION

It is known to employ various smoke treating materials in cigarettes, for example, granular·charcoal. Further, various methods and apparatus are known for making cigarette filter units which embody a mass of particulate charcoal therein. _Representa- tive of known methods and apparatus are U.S. Patents Nos. 3,312,151; 3,357,320; 3,357,321; 3,366,125; 3,610,112; 3,772,967; 3,807,286; 3,844,200; and 4,086,846., Such methods and apparatus, however, involve manufacture of an ultimate composite, continuous filter rod in which the space between two longitudinally separated plugs of a smoke filter material such as cellulose acetate plugs is filled with granular charcoal, various modes of effecting charcoal filling being disclosed. Such modes are not as a practical consideration fully effective for totally filling the space between the plugs. Nor are the methods disclosed readily adapted to optimized filling operation without undue particulate material spillage unless resort is had to expensive and complicated filling techniques. U.S. Patent 3,844,200 discloses method and apparatus in which a quantity of a granular form of smoke treating material, e.g., charcoal, clay, resins, etc. is deposited into a U-shaped filter material mass after which the legs of the U are closed to form a generally cylindrically shaped article containing spaced apart, centrally located pockets of the granular material. The article or continuous rod is then sectioned into appropriate lengths to provide individual cigarette filter components each containing a pocket of granular Material. Such component thus has the disadvantage that the granular material is centralized so that . at marginal encircling portions of the component, the smoke passes directly through the component without contacting the granular treating material.

SUMMARY OF THE PRESENT INVENTION

The present invention relates to a method and apparatus for forming a continuous filter rod of a fibrous material which is impregnated with or contains substantially uniformly di_st_ri-buted throughout the mass of the fibrous material, a particulate or granular material such as charcoal, a smoking treating resin material and the like. The continuous rod may be wrapped in.a wrapper material in conventional manner and thereafter be sectioned into lengths for delivery to the cigarette making operation and ultimate incorporation in cigarettes as smoke treating and filtering components.
In accordance with the invention, a bloomed and laterally widened, relatively thin, flat web of filter material such as a plasticized cellulose acetate tow is fed or advanced at a predetermined speed in a fixed line of travel which will take if past a deposit station at which the particulate material is to be deposited on and distributed substantially uniformly throughout the tow. A source of particulate material, such as granular charcoal in a hopper is disposed at the deposit station and has .an outflow, e.g., hopper bottom opening located adjacently above the web travel course. A rotary roller applicator is supported for rotation about a fixed axis transverse to the direction of web travel and is so positioned that a peripheral length portion of the roller applicator passes through the particulate material at the hopper outflow and propels particulate material onto the web, the propelling force being effective to distribute the charcoal uniformly throughout the web. Desirably the roller applicator rotates such that its peripheral speed is substantially equal to the travelling speed of the web and moreover, the roller applicator periphery closest point of approach to the Web is maintained such as to prevent deflection transmissive contact of the roller periphery with the web which, e.g., occurs with the roller 46 of the device described in U.S. Patent No. 3,844,200. In directing the web of tow in its travel from a stock thereof toward the deposit station, a guiding ring is employed to contact and align the tow in its travel course. However, such guiding ring is located an appreciable distance upstream of the deposit station so that having once passed the guiding ring, the web is unconstrained in its travel course therefrom to and through the deposit station, and for an appreciable distance beyond the . deposit station. Such feature taken together with the fact that no deflection transmissive contact of the roller applicator with the tow web occurs during particulate transfer eliminates any factors such as tow spread, vibration, etc., which could cause non-uniform distribution of the charcoal in the web or spill through the web of particulates at the deposit station.
"Unconstrained" as used herein is intended to mean the free travel of the tow web along a travel course in which the web does not come into contact with any structure or be acted upon by any force or influence as would tend to alter its particular state of cohesiveness, unintended spreading or bunching together of the fibers being an example of an undesirable alteration.
. A further feature of the invention involves the feeding of charcoal onto the tow web across its full lateral expanse and for such purpose, the peripheral length of the rotary roller applicator which passes through the particulate material at the outflow of the hopper is less than the width of the tow, to allow that lateral cascade of charcoal issuing from the ends of the roller applicator reaches and invests the web at its marginal regions at the deposit station but such cascade does not overreach said mar^g- ins and thereby spill over off the web.
The invention also provides apparatus for forming the filter rod, the rotary roller applicator desirably being provided as an elongated cylindrical structure having a plurality of spaced axially extending pockets at the periphery thereof with such pockets in a preferred embodiment being defined by means of a plurality of axially extending circularly spaced rods mounted on a cylindrical core member in an arrangement such that each pair of adjacent rods define a pocket. In rotating through the particulate material (charcoal). present at the hopper outflow, the pockets defined by each adjacent pair of rods become-filled with the charcoal and the charcoal is carried around from the point at which the charcoal is picked up and propelled from the pocket onto the advancing tow web at the deposit station. The rods which extend axially of the periphery of the cylindrical core member preferably are provided as stainless steel members and can be replaceably mounted on the core structure by means of removable end plate structures in which the rods are received.
After the charcoal impregnated tow web has travelled an .appreciable distance beyond the deposit station, it is brought into contact with a tongue guide unit which forms the web into a generally cylindrical shape following which it is wrapped in a conventional "plug wrap" wrapper.

BRIEF DESCRIPTION OF THE DRAWINGS

A fuller understanding of the nature and objects of the present invention will be had from the following detailed description taken in conjunction with the accompanying drawings showing by way of example, a preferred embodiment of the inventive . concept and in which:

FIG. 1 is a side elevational view of apparatus for forming filter rod and constructed in accordance with the principles of the present invention.
FIG. 2 is a top plan view of the apparatus depicted in FIG. 1.
FIG. 3 is a right end elevational view of the apparatus depicted in FIGS. 1 and 2.
FIG. 4 is a vertical sectional view taken along the lines 4-4 in FIG. 2.
F_IG. 5 is a schematic view depicting the principles of operation of the present invention for applying particulate material onto a travelling Web of fibrous material so as to uniformly distribute the particulate material throughout the travelling web structure.
FIG. 6 is a perspective view of a length of filter rod formed in accordance with the principles of the present invention, a portion of the length being broken away to indicate the internal structure of the rod.

Throughout the following description, like reference numerals are used to denote like parts in the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 6 of the drawings, the section 10 of rod shown is as it appears after same has been impregnated with particulate material, formed into a cylindrical shape and covered in an outer wrapping such as a conventional filter "plug wrap". The,rod section 10, includes a mass of compressed fibrous materials comprising intersecting and similarly arrayed lengths of individual fibers 12 and throughout the three-dimensional mass of which is distributed particles 14 of charcoal.
With reference with FIG. 5 which diagrammatically de- ^picts the manner of operation of the present invention, it will be seen that a web 16 of a bloomed laterally widened relatively thin and plasticized tow is advanced from a stock source thereof (as in FIG. 1) in a course which takes it around a guidance roller unit 22 following which the w_eb advances through a guiding ring 24 employed to ensure proper alignment and width adjustment of the advancing web when it reaches the deposit station 26 at which the particulate material, in this instance, charcoal, is deposited on the web.
At the deposit station 26, there is disposed a hopper 28 having a lower terminus chute section 30 for gravity delivery of the charcoal to an outflow opening 32 at the bottom of the chute section. Such outflow opening 32 is disposed adjacent to but a distance above the travelling web 16 and it is also located adjacent the rotating travel course of the periphery of a rotary roller applicator 40. The rotary applicator 40, it will be noted, is disposed for rotation about an axis 42 disposed transverse of the travel course of the web and the applicator so arranged that a peripheral length portion'thereof passes through the charcoal at the outflow 32 to pick up charcoal in the pockets 44 present at the outer periphery of the roller applicator and thence propelled outwardly from said pockets onto the travelling web. As can be noted, the pockets 44 are defined by adjacent ones of a plurality of rods 48 extending axially along the surface of the roller applicator.
The rotary roller applicator 40 is operated at a speed so as to produce a peripheral speed therein which is substantially, equal to the travelling speed of the web 16, which speed can be, e.g., 150,000 mm/min.
The invention provides that the full width of the web is impregnated with charcoal at the deposit station. To achieve.. this without producing any spillover of charcoal from the web at its margins, the length of periphery of the roller applicator 40 which rotates in the charcoal at chute opening 32 is made a ^pre- determined distance less than the width of the tow. -This is achieved by narrowing in the side walls of the chute section 30 and hence limiting-the length of opening 32 so that it is about 1/2" narrower at each end than the span between the margins of the web at the point of deposit of charcoal onto the web. In such manner lateral cascade (i.e., axially of the applicator) of charcoal reaches and invests the side marginal regions of the web but does not overflow therefrom. The differences are shown by the lines A-A and B-B in FIG. 3 which respectively denote the web width at the point of deposit, and the length of opening 32.
It is an important feature of the present invention that at the time the particulate material is being deposited on the travelling web, the web is travelling within a travel course which is unconstrained for an appreciable distance both upstream and downstream of the point of deposition of the charcoal. Since the web 16 of cellulose acetate tow material is of a sensitive character; any forces or influences acting thereon as might serve to alter the cohesive structure of the laterally widened relatively thin web could result in improper distribution of the charcoal throughout the mass or the spill-through of the charcoal so. that substantial quantities of charcoal instead of being embodied or impregnated within the tow would pass through the tow. 'By not constraining the tow for that travel course run, these problems are avoided. Thus, as will be noted in FIG. 5, from the point where the web passes through the guiding ring 24 until the impregnated web is ultimately wrapped into a generally'cylindrical configuration, the same does not come into contact with any structure or under influence of any force as would alter its character. Moreover, the mounting of the rotary roller applicator 40 is such that the periphery of the rotary roller applicator is maintained to prevent any deflection transmissive contact'of the roller periphery with the web. In certain of the devices disclosed in the prior art enumerated before, the applicator member actually contacts the tow and thus promotes the undesirable conditions noted above.
Turning now to FIGS. 1-3, it will be seen that the apparatus 70 includes a drive housing 72 in which is disposed various drive sprockets 74 and driving belt 76 which are employed to impart rotary drive to the rotary roller applicator 40. Such drive is synchronized to impart to the rotary roller applicator a peripheral speed substantially equal to that of the travelling web 16..
Disposed adjacent the housing 72 is a vertically disposed hopper 28 employed to contain a quantity of granular material, for example, charcoal. The hopper is of taperihg configuration, that is, it has a lower downwardly and inwardly tapering terminus chute section 30 which terminates in an outflow opening 32 disposed adjacent the periphery of the rotary roller applicator 40. Such outflow is also spaced a distance above the travelling web.
Upstream of the point of deposit shown generally at 80,.. there is provided the guidance roller 22 and guiding ring 24 which ,latter component as noted earlier serves to align and properly orient the travelling laterally widened relatively thin web to present it in a fixed straight line travel course of certain width ias it passes beneath the rotary roller applicator. As the web continues its travel leftwardly (FIG. 1), the same is as indicated unconstrained until it reaches the area of _the.tong_ue guide assembly 82 which component serves to form the tow web into a generally cylindrical shape. Concurrently with the passage of the now cylindrically configured tow web through the tongue guide assembly 82, there is advanced at the underside of same a continuous length of plug wrap material 84 which by means of a device well known to those skilled in the art wraps the plug wrap in a fully enclosing course about the cylindrically shaped web.
As those skilled in the art will readily appreciate, the tow advancing from a stock thereof as at roll 20 is bloomed or opened up by means of air jets in conventional fashion and-can be sprayed with a liquid form of plasticizer such as triacetin to effect adhesion of the fibers of the tow where they have crossing points with other fibers and hence produce a cohesive three-dimensional structure.
As will be noted in FIG. 3, the tow entering the guiding ring 24 contacts the same at the lateral edges of its mass after passing in contact under guiding roller 22. However, once the tow has passed beyond the guiding ring 24 it is no longer in its travel course in contact with any other part or surface within the overall apparatus structure until it passes through the tongue guide assembly 82 leaving the latter through its end aperture 90 in the form of a generally cylindrically shaped continuous member.
With reference to FIG. 4, it will be seen that the rotary roller applicator 40 is comprised of a generally elongated cylindrical core 100 which is provided at its opposite ends with retainer plates 102 fastened to the core 100 by means of screws 104, the inner faces of the retainer plates carrying annular mounting rings 106 each of which is provided with a series of circularly spaced holes for reception of a like plurality of stainless steel rods 48 which lay against the outer surface of the core. In an actual embodiment, 20 rods are employed and each is 1/8" in diameter. The rods 48 function to provide between adjacent pairs of each, a pocket 44 at the periphery of the rotary roller applicator for picking up charcoal at the outflow from the hopper 28 and propelling same onto the travelling web to uniformly distribute the charcoal throughout the web structure.
To accommodate various types of tow, the guiding ring 24 is made adjustable and for such purpose is slidably received in bracket 110 and an adjusting nut arrangement shown at 112 and 114 can be employed to elevate or lower the'ring.
The present invention thus provides improved method and apparatus for making a filter rod in which charcoal is substantially uniformly distributed throughout a filter material mass and effects same with practically no waste of charcoal in the impregnation operation and, accordingly, less dust is created and a more uniform ultimate product is obtained.
While there is disclosed but one embodiment of the method and apparatus of the present invention, it is possible to produce still other embodiments without departing from the scope of the inventive concept herein disclosed and accordingly, it should be understood that all matter contained in the above description, and in the accompanying drawings should be interpreted as illustrative and not in a limiting sense.

Claims

1. A method for forming filter rod containingparti- culate material substantially uniformly distributed therethrough, said method comprising

feeding a bloomed and laterally widened relatively ,thin web of fibrous filter material in a fixed travel course at a predetermined speed,

providing a source of the particulate material at a deposit station disposed at a location along said fixed travel course with an outflow from said source placed adjacently above said web, and

transferring particulate material from said.source onto said web with a rotary roller applicator rotating about a fixed axis transverse to the web travel course with a peripheral length thereof passing through particulate material at said outflow and propelling said particulate material onto said web in a path generally codirectional to the web travel, the web travel for an appreciable distance both upstream and downstream of said deposit station being unconstrained, the speed of the periphery of the rotary roller applicator being substantially equal to the speed of the web, the closest point of approach of said rotary roller applicator periphery to said web being maintained such as to prevent deflection transmissive contact of said roller periphery with said web.

2. The method of claim 1 in which the web of filter material is cellulose acetate and the particulate material is granular charcoal.

3. The method of claim 2 in which the filter material is subjected to a plasticizing operation before it passes to the deposit station to effect joining together of the fibers thereof to form a cohesive mass therewith.

4. The method of claim 1 in which the peripheral length of the rotary roller applicator passing through the particulate material at said outflow is sufficiently less than the width of the web, whereby cascade of particulate material from the ends of said applicator and laterally of said web is not carried beyond the margins of said web.

5. The method of claim 1 in which the particulate material containing web is formed into a generally'cylindrical shape a distance downstream of said deposit station and is thereafter enclosed with a wrapper.

6. In apparatus for forming filter rod containing particulate material substantially uniformly distributed therethrough,

means for feeding a bloomed and laterally widened relatively thin web of fibrous filter material in a fixed travel course at a predetermined speed,

means for holding a source of particulate material at a deposit station disposed at a location along said fixed travel course, said holding means having an outflow therefrom positioned adjacently above said web travel course,

a rotary roller applicator and means for rotating same,

means for supporting said rotary roller applicator for rotation about a fixed axis disposed transverse to the web travel course and in a position-in which a peripheral length of said roller applicator during rotation thereof passes through the particulate material at said outflow for propelling particulate :material from said outflow in a path generally codirectional to the web travel and into said web to effect distribution of said particulate material throughout said web, and

web guidance means disposed an appreciable distance :upstream of said deposit station for guiding the travel of said web toward said deposit station, the web travel course from said guidance means and for an appreciable distance downstream of said deposit station being unconstrained,

said applicator rotating means being effective to rotate said applicator such that the peripheral speed thereof is substantially equal to that of said web, said supporting means supporting said applicator in a disposition wherein the closest point of approach of said applicator periphery to said web is maintained such as to prevent deflection transmissive contact of said periphery with said web.

7. The apparatus of claim 6 in which said rotary roller applicator is an elongated cylindrical member having a plurality of spaced axially extending pockets at the periphery thereof.

8. The apparatus of claim 7 in which said cylindrical member is provided at the periphery thereof with a plurality of axially extending circularly spaced rods, adjacent ones of said rods defining each pocket.

9. The apparatus of claim 6 in which said holding means comprises a hopper, said hopper having a downwardly depending terminus chute section terminating adjacent the periphery of said rotary roller applicator in an outflow opening from said section.

10. The apparatus of claim 9 in which the width of the outflow opening is a predetermined dimension of lesser width than the width of said web at the deposit station.

11. The apparatus'of claim 6 further comprising means disposed downstream of said deposit station for forming the particulate material impregnated web into a generally cylindrical shape.