GB2042319A - Tobacco smoke filtering unit - Google Patents

Abstract

A tobacco smoke filtering unit for a smoking implement having a wrapper 2 defining a filtering chamber at an end constituting a mouthpiece comprises a separator wall 6 in sealing contact with the wrapper and dividing the filtering chamber into a first compartment closer to the mouthpiece end and a second compartment remote therefrom, the separator wall defining an orifice 7 for the passage of tobacco smoke, a baffle 8 in the first compartment facing the orifice, and a tobacco smoke filter 10 in the first compartment, the baffle and filter defining a narrow air space with the separator wall 6. <IMAGE>

Description

SPECIFICATION Tobacco smoke filtering unit The present invention relates to a tobacco smoke filtering unit for a smoking implement, such as a cigarette, having a wrapper defining a filtering chamber at an end constituting a mouthpiece.

It is known that smoking of tobacco produces not only aromatic components in the smoke which are desirable to the smoker but also noxious components which, when inhaled by the smoker, may irritate the mouth, windpipe and lungs or may even cause illnesses, including cancer. Particularly when the final portion of the tobacco is smoked, initially generated noxious substances may be redeposited in the tobacco and converted into smoke again to be inhaled Various types of filters have been proposed to overcome this problem and to filter at least some of the noxious components out of the smoke before it is inhaled. None of the known filters has met all filtering requirements while maintaining the desired quality and aroma of the smoke. The same holds for various pre-treatments proposed to remove the noxious substances from the tobacco before it is smoked.

It is an object of this invention to minimize the presence of noxious components in tobacco smoke before it is inhaled but without loss of the desired quality of the smoke and a deterioration of its aroma. It is another object of the invention to provide a filter more effective in this respect than the conventional paper filters used in cigarettes or tobacco pretreatments designed to accomplish similar results but which is small enough for ready use in cigarettes or similar tobacco smoking implements.

The invention consists in a tobacco smoke filtering unit for a smoking implement having a wrapper defining a filtering chamber at an end constituting a mouthpiece, which comprises a separator wall in sealing contact with the wrapper and dividing the filtering chamber into a first compartment closer to the mouthpiece end and a second compartment remote therefrom, the separator wall defining an orifice for the passage of tobacco smoke, a baffle in the first compartment facing the orifice, and a tobacco smoke filter in the first compartment, the baffle and filter defining a narrow air space with a separator wall.

In order to make the invention clearly understood, reference will now be made to the accompanying drawings which are given by way of example and in which: Figure 1 shows a longitudinal section of one embodiment of the filtering unit of the invention; Figure 2 is a like view of another embodiment; Figure 3 is a like view of yet another and preferred embodiment; Figure 4 is a perspective view of a portion of the filtering unit of Fig. 3; Figure 5 shows a mould for manufacturing the filtering unit portion of Fig. 4; and Figure 6 shows a modification of the embodiment of Fig. 1 in the same view.

Referring now to the drawings, wherein like reference numerals designate like parts functioning in a like manner in all figures, Fig. 1 shows the mouthpiece end of a cigarette 1 filled with tobacco 3 packed in a paper wrapper 2. At the mouthpiece end, tobacco filtering unit 4 is placed into a filtering chamber defined by wrapper 2 and mouthpiece 5 surrounds the wrapper at the mouthpiece end, all in a generally known manner.

The tobacco smoke filtering unit according to the present invention comprises an additional filter structure designed to reduce the noxious component in tobacco smoke passing therethrough. This filter structure comprises separator wall 6 in sealing contact with wrapper 2 and dividing the filtering chamber into a first compartment closer to mouthpiece 5 and a second compartment remote therefrom and closer to tobacco 3, the separator wall defining an orifice for the passage of tobacco smoke. Separator wall 6 is impermeable to the smoke so that the smoke can pass only through the orifice. The filter structure further comprises baffle 8 in the first compartment facing orifice 7. Any suitable tobacco smoke filter 10 is arranged in the first compartment at the mouthpiece end as part of the filter structure.Baffle 8 and filter 10 define narrow air space 9 with separator wall 6 of the smoke filtering unit wherein noxious components of the smoke may be deposited.

Baffle 8 is preferably constituted by a smoke-impermeable sheet covering at least a portion, preferably, half, of the surface area of filter 10 and is arranged to be impacted by the smoke passing through orifice 7. A useful baffle sheet material is adhesive paper bonded to filter 1 0. The surface area of baffle 8 is so selected that it corresponds to the diameter of the cross section of the smoke stream passing through orifice 7.

Further tobacco smoke filter 11 is arranged in the second compartment of the filtering unit and is illustrated as a filtering layer or sheet separating tobacco 3 from apertures separator wall 6 so as to prevent orifice 7 from being clogged by tobacco. Instead of the thin filtering layer or sheet 11 illustrated in Fig. 1, this further filter may be a conventional smoke filter of the same type as filter 10 (see Fig. 2). The effectiveness of tobacco smoke filtering unit 4 will be enhanced by leaving narrow air space 1 2 between further filter 11 and orifice 7 to serve as a smoke collection space.The velocity of the smoke flow and the corresponding deposition of the noxious smoke components will be increased when each draw on the cigarette moves an accumulated amount of smoke from space 12, rather than moving the entire smoke from tobacco 3 through filter 11 at each draw.

Orifice 7 has a length sufficient to orient the smoke passing therethrough in a predetermined direction to impact on baffle 8, the orifice causing the smoke to move as a narrow stream and to be accelerated, noxious components of the smoke being deposited on impact on the baffle 8. Additional filtering is obtained by conventional filters 11 and 1 0.

Experiments have indicated a preferred length of orifice 7 to be about 0.5 to 1.5 mm and the distance of baffle 8 from separator wall 6 to be about 0.7 to 0.8 mm, the diameter of the orifice being about 0.6 to 0.7 mm.

To avoid redundancy in the description, the parts of the embodiment shown in Fig. 2, designated by the same reference numerals are equivalent in structure and function to those of Fig. 1. The filtering unit of this embodiment further comprises spacing element 14 extending along the axis of filtering unit 4 and connecting baffle 8 to separator wall 6 adjacent thereto, the separator wall and the spacing element constituting a stable filter structure. As shown, the spacing element projects from the filter structure to constitute a spacer for further filter 11 from the filter structure. The preferred length of the spacer is about 3 to 4 mm and the baffle 8 is a half disc. The separator wall, the baffle and the spacing element are integral with each other in the illustrated embodiment to form unitary structure 1 3 inserted into the mouthpiece end of the cigarette.

The separator wall may be constituted by a sheet of substantially rigid carton and is formed by a disc whose circumference is selected to be in sealing contact with wrapper 2. It may be adhesively bonded thereto, if desired, and the smoke will pass essentially only through orifice 7. Filter structure 1 3 has a total length so selected that it will serve as a spacer between filters 10 and 11 to position the filters in the mouthpiece end of the -ciga--- rette. The integral filter structure 1 3 may be pressed in one piece.

In this filtering unit, the path of the tobacco smoke leads through filters 11 into smoke collecting space 1 2 whence the accumulated smoke is drawn through orifice 7 where the smoke is oriented in a narrow stream, this compressed stream of tobacco smoke impacting on baffle 8 whence the smoke passes through air space 9 and filter 10 into the mouth of the smoker. Nicotine and tar are deposited on baffle 8 in the form of a dark brown layer.

In the preferred embodiment of Fig. 3 which has proved to be particularly effective, integral filter structure 1 3 comprises further separator wall 1 5 in the second compartment and close to separator wall 6, further separator wall 15 defining orifice 1 6 for the passage of tobacco smoke, and the separator walls defining narrow air space 20 therebetween. In this embodiment, separator wall 6 also functions as a baffle on which the stream of smoke passing through orifice 1 6 impacts, thus providing a double deposition of noxious components of the smoke and increasing the amount of such components withdrawn from the smoke in the filter unit.

Fig. 4 illustrates filter structure 1 3 of Fig. 3 constituted as unitary structure 21 produced by injection moulding, pressing or casting.

Fig. 4 shows mould 22 for the production of unitary filter structure 21 of Fig. 4. This mould comprises two mould halves 24, 25 connected by hinges 23, each mould half defining grooves 26 for the material to be moulded, such as paper, synthetic resin or like mouldable material. The grooves 26 are arranged congruently in both mould halves and the groove portions designed to produce connecting and spaced element 14 are arranged to interconnect a series of structural parts extending perpendicularly thereto. In this manner, several structures may be moulded in a single moulding step. Since they are congruent, the filter structure removed from each half mould can be bonded together to produce the finished filtering structures in series, and the filter structures may be inserted into the cigarettes after cutting off one half of an end disc constituting the baffle.

Fig. 6 illustrates a modification of the tobacco smoke filtering unit of Fig. 1, this unit being constituted by two separate filter parts 4a and 4b. Each filter part comprises sleeve 19a, 1 9b encasing respective conventional smoke filter 10, 11. Like filtering unit 4 of Fig. 1, each filter part 4a, 5b comprises separator wall 6, 1 5 defining therein orifice 7, 16, air space 9, 1 2 being defined between the smoke filter and the separator wall of each filter part. The orifices are displaced or offset in relation to each other so that the stream of smoke passing through orifice 1 6 cannot enter orifice 7.Preferably, the orifices are positioned in the separator walls diametrically opposed to each other and close to the edge of the separator wall defining the orifice.

Each sleeve 19a, 19b has a respective extension 17, 18 projecting beyond,respective separator wall 6, 15, the two extensions having the same length and extending over half the circumference of the sleeves so that, when the two parts are axially aligned, the two extensions form a complete cylinder and define space 20 between separator walls 6, 1 5. Orifices 7 and 1 6 are positioned diametrically opposed and 90 degrees from the abutment plane of extensions 1 7 and 1 8.

Similarly to the embodiment of Fig. 3, this composite, two-part tobacco smoke filtering unit has two baffles, separator wall 6 operat ing as a baffle for the smoke coming from orifice 16, in addition to baffle 8 whereon the smoke coming from orifice 7 impacts. The length of extensions 17, 18, i.e. the width of space 20 is so selected that the impacting streams of smoke cause optimal removal of noxious substances.

The two-part filtering unit of Fig. 6 has various manufacturing advantages. For instance, filter parts 4a and 4b may be, with slight modifications, produced as identical parts and they may be used singly, as in the embodiment of Fig. 1, or may be combined, as shown in Fig. 6, to produce improved reduction of condensate.

Claims (1)

1. A tobacco smoke filtering unit for a smoking implement having a wrapper defining a filtering chamber at an end constituting a mouthpiece, which comprises a separator wall in sealing contact with the wrapper and dividing the filtering chamber into a first compartment closer to the mouthpiece end and a second compartment remote therefrom, the separator wall defining an orifice for the passage of tobacco smoke, a baffle in the first compartment facing the orifice, and a tobacco smoke filter in the first compartment, the baffle and filter defining a narrow air space with a separator wall.

2. A tobacco smoke filtering unit as claimed in claim 1, comprising a futher separator wall in the second compartment and close to the first-named separator wall, the further separator wall also defining an orifice for the passage of tobacco smoke, and the separator walls defining a narrow air space therebetween.

3. A tobacco smoke filtering unit as claimed in claim 2, wherein the orifices are positioned in the separator walls diametrically opposed to each other.

4. A tobacco smoke filtering unit as claimed in claim 2 or 3, wherein the orifices have a smoke outlet end facing the mouthpiece end flush with the separator walls.

5. A tobacco smoke filtering unit as claimed in claim 1, wherein the wrapper is of paper.

6. A tobacco smoke filtering unit as claimed in claim 1 or 5, comprising a further tobacco smoke filter in the second compartment.

7. A tobacco smoke filtering unit as claimed in claim 1 or 2, wherein each orifice has a length sufficient to orient the smoke passing therethrough in a predetermined direction.

8. A tobacco smoke filtering unit as claimed in claim 7, wherein the length of each orifice is about 0.5 to 1.5 mm and the distance of the baffle from the separator wall is about 0.7 to 0.8 mm.

9. A tobacco smoke filtering unit as claimed in claim 8, wherein the diameter of each orifice is about 0.6 to 0.7 mm.

1 0. A tobacco filtering unit as claimed in claim 1 or 2, wherein the wrapping is adhesively bonded to each separator wall.

11. A tobacco smoke filtering unit as claimed in claim 1 or 2, wherein each separator wall is constituted by a,sheet of substantially rigid carton.

1 2. A tobacco smoke filtering unit as claimed in claim 1 or 2, further comprising a spacing element extending along the axis of the filtering unit and tonnecting the baffle to the separator wall adjacent thereto, the separator wall and the spacing element constituting a stable filter structure.

1 3. A tobacco smoke filtering unit as claimed in claim 12, comprising a further tobacco smoke filter in the second compartment, the spacing element projecting from the filter structure to constitute a spacer for the further filter from the filter structure.

14. A tobacco smoke filtering unit as claimed in claim 13, wherein the spacer has a length of about 3 to 4 mm.

1 5. A tobacco smoke filtering unit as claimed in claim 12, wherein the baffle is a half-disc.

1 6. A tobacco smoke filtering unit as claimed in claim 15, wherein the separator walls, baffle and spacing element are integral with each other.

1 7. A tobacco smoke filtering unit as claimed in claim 1, wherein the smoking implement is a cigarette and the unit is a unitary structure inserted into the mouthpiece end of the cigarette.

1 8. A tobacco smoke filtering unit as claimed in claim 1 or 2, wherein the baffle is constituted by a smoke-impermeable sheet covering at least a portion of the filter and arranged to be impacted by the smoke passing through the orifice.

1 9. A tobacco smoke filtering unit as claimed in claim 18, wherein the smokeimpermeable baffle sheet is adhesive paper bonded in the filter.

20. A tobacco smoke filtering unit as claimed in claim 18 or 19, wherein the smoke-impermeable baffle sheet covers about half the surface area of the filter.

21. A tobacco smoke filtering unit as claimed in claim 1 or 2, wherein each orifice is arranged close to the edge of the separator wall defining the orifice.

22. A tobacco smoke filtering unit as claimed in claim 1, comprising a sleeve fitting into the wrapper and surrounding the separator wall.

23. A tobacco smoke filtering unit as claimed in claim 22, comprising a further filter structure including a sleeve fitting into the wrapper and a separator wall surrounded by the sleeve of the filter structure, the latter separator wall also defining an orifice for the passage of tobacco smoke, the sleeves having extensions projecting beyond the respective separator walls and the extensions forming a cylinder in axial alignment with the sleeves and defining a narrow air space between the separator walls.

26. A tobacco smoke filtering unit as claimed in claim 93, wherein the orifices are offset in relation to each other.