JPS6126351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tobacco filter used in smoking devices such as cigarettes.

Filter chip cigarettes equipped with ventilation means for introducing ventilation air into the filter are well known. Its purpose is to reduce the absorption of smoke components and also to cool the main stream of smoke. When ventilation air enters the filter made of fibrous filter material such as cellulose acetate through the chip wood ventilation zone around the filter periphery, the incoming air causes cigarette smoke to be confined to a narrow area of the filter plug. This is known to result in a relatively narrow flow of smoke from the mouth end of the plug into the smoker's mouth and to limit the mixing of ventilation air with tobacco smoke. As a result, only a small amount of smoke cooling occurs.

It is therefore an object of the present invention to provide a cigarette filter in which a smoker can enjoy superior smoke characteristics and in which a large portion of the smoke can be better cooled when using the filter.

In the present invention, the plug has one or more air circulation grooves on its peripheral edge, and the grooves become deeper from the inlet end to the outlet end of the groove, and when the plug is viewed in an exploded view, the grooves are aligned with the shaft of the plug. They are starting to intersect,
Furthermore, there is provided a cigarette filter having a rod-shaped plug of filter material, characterized in that the groove has an air-permeable outlet surface at its outlet end.

In order to better understand the invention and facilitate its implementation, the following description is given by way of example of schematic drawings.

In the drawings, FIG. 1 shows a filter plug with a helical peripheral air flow groove. FIG. 2 shows a cross-section of the plug along the line of FIG. 1 and the chipping gripper superimposed thereon. FIG. 3 shows a part of a filter tip cigarette with a modification of the plug of FIG. 1, and FIG. 4 shows a cross section of a filter having a plug of a different shape from that of FIG. FIG. 5 shows a cross-sectional view along the line of FIG. 4.

The filter plug 1 shown in FIG. 1 is made of a filter material made of fibrous cellulose acetate and has self-shape retention. A number of helical air circulation grooves 2 are provided around the circumference of the plug 1. FIG. 2 shows a cross section of the air flow groove 2 along the length of the groove. As can be seen in FIG. 2, the depth of the groove increases from the inlet end 3 towards the outlet end 4. When attached to a cigarette rod to form a filter tip, the plug 1 is fixed to a rod (not shown) by the tip material 5. As can be seen from FIG. 2, the cigarette rod is located to the right of the plug 1 in this case. As shown in Figure 2,
The plug 1 is inserted at a position where a row of through holes 6 provided in the chip overlaps the inlet end area of the air circulation groove 2.
, and at least one through hole 6 is arranged so as to communicate with each of the air circulation grooves 2.

A preferred method for forming the air flow grooves 2 is as described in British Patent Specification No. 1507765 by cutting the filter rod material to make the plug 1 or several plugs 1 by suitable shaping means. It is to be subjected to the heat molding method shown in No. By suitably selecting the conditions of the thermoforming process, the air flow groove 2 can be made such that its longitudinal surface 7 is substantially impermeable to the air flow and the outlet end face 8 is permeable to the air flow. is formed.

When the filtered cigarette of FIGS. 1 and 2 is smoked, ambient air is drawn into the air flow groove 2 through the through hole 6. The air flow groove 2 is a helical passage, and the depth of the air flow groove 2 increases in the direction of the air flow, so that the ventilation air flows through the plug 1 with an inward spiral movement. to go into. This has the effect of improving the mixing of cigarette smoke and ventilation air passing through the filter plug 1.

The cigarette in Figure 3 consists of a cut tobacco rod 10 wrapped in paper 11 and a tip material 14 attached to this rod.
and a filter 12 having a plug 13 attached by. Filter plug 1
3 is different from plug 1 in FIG.
It has a helical air flow groove 15 in the upstream region and a number of parallel air flow grooves 16 opening at the mouth end of the plug 13. Similar to the air flow groove 2 of FIGS. 1 and 2, the longitudinal surface of the air flow groove 15 is substantially air impermeable;
This may also be the case with the surfaces of the parallel air flow grooves 16 opening at the mouth end. Two rows of through hole groups 17 and 1
Reference numeral 8 surrounds the plug 13 at a position overlapping the upstream end of the helical groove 15 and the parallel air circulation groove 16 opening at the suction end. 16
provide a means for introducing ambient air into the

If desired, the plug 13 may be two adjacent small plugs, one of which has a helical air flow groove 15 and the other a parallel air flow groove 16 opening at the mouth end.

When the cigarette of FIG. 3 is smoked, a first stream of peripheral air enters the filter plug 13 through the helical air flow groove 15 and is thoroughly mixed with the tobacco smoke by the swirling motion already described. Another stream of air enters the smoker's mouth from the parallel air flow grooves 16 opening at the mouth end without mixing or substantially mixing with the tobacco smoke.

The filter shown in FIG. 4 has a self-retaining filter plug 20 provided with a single row of annular air flow grooves 21. The filter plug 20 shown in FIG. The air flow grooves 21 each have an inlet end and an outlet end and substantially connect to the filter plug 20.
perpendicular to the axis of the As can be seen from FIG. 5, each air flow groove 21 increases in depth towards its outlet end. Outlet end face 22 is air permeable. The other surfaces of the air flow grooves 21 are substantially air impermeable.

A tip material 23 is superimposed on the filter plug 20 for attaching the plug 20 to a cigarette rod (not shown in FIG. 4). This chip material 23 has a microporous zone 24 surrounding the plug 20 at a position overlapping the air flow groove 21.

When the filter cigarette of FIGS. 4 and 5 is smoked, ambient air is drawn into the air flow grooves 21 from this microporous zone 24. The air enters the filter plug 20 with a helical movement through the outlet end face 22 of the air flow groove 21, the helical movement ensuring a good mixing of cigarette smoke and air. Any of the ventilation holes in the embodiments described above may use a chip material having such a microporous zone. If desired, the chip material may be overlaid with an air permeable plug wrapper, in which case the chip material becomes an air impermeable outer layer with perforations. Of course, it is desirable that the tip material 5 is longer than the plug wrapper.

It should of course be noted that the dimensions of the through holes 6, 17 and 18 shown in the drawings are exaggerated for ease of explanation.

[Brief explanation of the drawing]

Fig. 1 shows a filter plug with a helical air flow groove, Fig. 2 shows a cross-section of the plug along the line of Fig. 1 and part of the tipping grabper, and Fig. 3 shows a modification of the plug of Fig. 1. 4 is a cross section of a filter having a plug of a different shape than that of FIG. 1; FIG. 5 is a cross-sectional view taken along the line of FIG. 4; FIG. 1, 13, 20... Plug, 2, 15... Spiral air circulation groove, 3... Inlet end, 4... Outlet end, 5, 1
4, 23... Chip material, 6, 17, 18, 24... Through hole, 7... Length direction surface, 8, 22... Outlet end surface, 10
...Cigarette rod, 11...Paper, 12...Filter, 16...Air circulation groove, 21...Air circulation groove.

Claims (1)

[Scope of Claims] 1. The filter plug has one or more air circulation grooves in its peripheral portion, the grooves become deeper from the inlet end to the outlet end of the groove, and the groove further has air permeability at the outlet end. A cigarette filter consisting of a rod-shaped plug made of filter material and a tip material having an outlet surface of . 2. The filter according to claim 1, wherein the inlet end of the air circulation groove is located farther from the suction end of the filter plug than the outlet end. 3. The filter according to claim 2, wherein the air circulation groove has a spiral shape. 4. The filter according to claim 1, wherein the inlet and outlet ends of the air flow groove are equidistant from the suction end of the filter plug. 5. Claims 1, 2, or 3 in which the air circulation groove has side and bottom surfaces that are less permeable to air flow than the air-permeable outlet surface that the air circulation groove has at its outlet end.
4. The filter according to item 4. 6. Claims 1 or 2 or 2, which have air circulation grooves parallel to a plurality of filter plugs that are open to the intake end and extend from the intake end of the filter plug to near the area where the air circulation grooves are provided. The filter according to item 3, item 4, or item 5. 7. A chip material according to claim 6, which is made of a chip material having ventilation holes at the end far from the suction end of the air circulation groove parallel to the filter plug opening at the inlet end and the suction end of the spiral air circulation groove. filter. 8. The filter according to claim 7, wherein the ventilation holes are microporous zones of the chip material. 9 A filter plug consists of two adjacent small plugs, one of which has one or more helical air circulation grooves, and the other of which has one or more helical air circulation grooves parallel to the filter plug opening at the inlet end. The filter according to claim 6, 7, or 8, having air circulation grooves.