A PROCESS FOR THE PRODUCTION OF A SMOKING MATERIAL FROM CIGARETTE MAKER WINNOWINGS AND APPARATUS THEREFOR

Abstract: A process for converting cigarette tobacco winnowings into usable form for cigarette making, comprises crushing the winnowings, which have a moisture content compatible with cigarette making, effecting a first sieving operation on the resulting crushed winnowings, and effecting a second sieving operation on the smaller fraction resulting from the first sieving operation to remove particles unsuitable for direct use. Any larger fraction resulting from the first sieving operation may be subjected to cutting and thereafter a third sieving operation. Suitable apparatus for converting cigarette tobacco winnowings having a moisture content compatible with cigarette making into usable form for cigarette making, comprises crushing rollers (11, 12) to which the winnowings are fed, a sieve (18) arranged to receive the crushed winnowings from the crusher, and a second sieve (19) provided to separate the tobacco usable for cigarette making from tobacco dust. The apparatus may include a cutter (23, 24) for receiving and cutting the larger fraction of the sieved crushed winnow­ ings. The three operations of crushing, sieving and cutting are all advantageously performed on the tobacco at cigarette maker moisture. It is also performed at ambient pressure and temperature, thereby greatly reducing capital costs over processes requiring heating, cooling, pressuring or moisture variation.

Description: The invention relates to a process for the production of a smoking material, for example, tobacco for use in cigarettes, and an apparatus for carrying out this process. Cigarette maker winnowings typically make up approximately 1% of the total tobacco production and comprise mainly coarsely cut pieces of stem, midrib or stalk, but can include some lamina and reconstituted sheet. The winnowings are unsuitable for use in cigarettes due to their hard 'woody' nature, which, apart from giving poor burning characteristics tend to tear or pierce the cigarette wrapping. A known method of using winnowings is to reduce it to dust and then to use the dust in the manufacture of reconstituted sheet, resulting in the winnowings passing through the whole conditioning/cutting process a second time. Prior art document US-A-4195646 discloses a process and apparatus spalling tobacco stems with subsequent sieving. Further US-A-3219042 discloses a method of treating tobacco whereby stem rolling is followed by stem cutting. An object of the invention is to provide a method of preparing the cigarette maker winnowings without any further conditioning being required, such that they may be directly recombined with the tobacco flow to the cigarette makers. According to the invention there is provided a process for converting cigarette tobacco winnowings which have a moisture content compatible with the needs of cigarette making, into an acceptable product in a form suitable for cigarette making comprising the steps of: effecting a crushing operation on the winnowings, effecting a first sieving operation on the resulting crushed winnowings to remove oversized particles, and effecting a second sieving operation on the smaller fraction resulting from the first sieving operation to separate out acceptable product from tobacco dust; characterised in that said crushing operation is carried out between a pair of rollers, said oversized particles are subjected to a cutting operation separate from the crushing operation to reduce their size, and are passed directly back to said first sieving operation. In this manner the winnowings are, at maker moisture content (i.e. approximately 14%), reduced to a size and form suitable for addition to conventionally produced lamina and stalk for use in cigarette manufacture. Further according to the invention there is provided an apparatus for converting cigarette tobacco winnowings which have a moisture content compatible with the needs of cigarette making, into an acceptable product in a form suitable for cigarette making, comprising crushing means for crushing the winnowings, first sieving means arranged to sieve the output of the crushing means to separate out oversized particles, conveying means arranged to convey the oversized particles from the first sieving means, and second sieving means arranged to sieve the smaller fraction from the first sieving means to separate out acceptable product from tobacco dust; characterised in that said crushing means comprises a pair of rollers, and a cutter device is interposed in said conveyor means from said first sieving means, to cut the oversized particles from the first sieving means, and the conveyor means carries cut particles therefrom directly back to the first sieving means. Preferred features of the invention are set out in the dependent claims. The invention will now be described by way of example with reference to the accompanying drawing showing a schematic perspective view of the crusher, shredder and sieves. The winnowings, which may be stems, midribs and veins with or without lamina or reconstituted sheet, are fed, either by gravity or by powered means, between two contra-rotating rollers 11, 12 at a pinch gap of typically zero millimetres, but may be as large as 1.0 millimetres. The rollers are provided at their ends with meshing gear wheels 13, 14 and 15, 16 of which one, 16, is driven by shaft 17. After passing through the rollers, the tobacco is conveyed, either by gravity or by powered means, to a series of sieves 18, 19. Sieving is carried out in three stages. Firstly, the tobacco is graded into particles passing through the sieve 18 of aperture size preferably between 6 mm. and 1 mm. (the first sieving operation). The tobacco passing through the first sieve 18 is sieved on the second sieve 19 of aperture size preferably between 4 mm. and 150 microns (most desirably substantially 850 microns). Tobacco passing through the second sieve 19 may be deemed to be too small for use in cigarettes and may be passed on by a chute 20 to be made into reconstituted sheet. Tobacco remaining on the second sieve 19 is deemed to be suitable for direct addition into the tobacco flow line for use in making cigarettes. Tobacco remaining on the first sieve 18 is deemed too large for direct use in cigarettes and is conveyed to a size reduction stage of the apparatus. Size reduction of the flattened winnowings which have not passed through the first sieve 18 is effected by a cutter comprising two series 23, 24 of contra-rotating overlapping steel disks of thickness typically between 0.10 mm. and 2.0 mm. (most desirably substantially 0.8 mm). The outer periphery of the disks may be cylindrical, serrated or have suitable cut outs to assist the material feed. The cutting disks may be interspaced by fixed members, which also guide the winnowings through the cutting zone. The flattened winnowings are fed to the cutter, either by gravity or by powered means. The cut product is then conveyed back to the first sieve 18 of the two stage sieve via a chute 25 where it is again graded (second sieving operation). Any product which is still too large is recirculated through the cutter until it is of a size suitable for use in cigarette manufacture, or has been reduced to dust. The product may be further processed to enhance the filling power (cc/gram) typically by using one of the known processes for expanding tobacco (e.g. Patent Nos: GB-A-1431123, GB-A-1570270 Philips Morris). This improvement process may be performed either before the crushing process or after the sieving process. The three operations of crushing, sieving and cutting are all advantageously performed on the tobacco at cigarette maker moisture content. It is also performed at ambient pressure and temperature, thereby greatly reducing capital costs over processes requiring heating, cooling, pressurising or moisture variations. Flattening the winnowings by crushing ensures that the cut winnowings are pliable enough to be used in cigarette manufacture with minimal possibilities of their puncturing the cigarette papers. In this way winnowings from the maker may be processed into a usable form for cigarette making. Since the winnowings are already conditioned at cigarette maker moisture content the processed winnowings can be returned to the main body of cut tobacco resulting from threshing, classification, cutting, blending and conditioning.

Claims: A process for converting cigarette tobacco winnowings which have a moisture content compatible with the needs of cigarette making, into an acceptable product in a form suitable for cigarette making comprising the steps of: effecting a crushing operation (12) on the winnowings, effecting a first sieving operation (18) on the resulting crushed winnowings to remove oversized particles, and effecting a second sieving operation (19) on the smaller fraction resulting from the first sieving operation to separate out acceptable product from tobacco dust; characterised in that said crushing operation is carried out between a pair of rollers (11, 12), said oversized particles are subjected to a cutting operation (23, 24) separate from the crushing operation to reduce their size, and are passed directly back to said first sieving operation. An apparatus for converting cigarette tobacco winnowings which have a moisture content compatible with the needs of cigarette making, into an acceptable product in a form suitable for cigarette making, comprising crushing means (12) for crushing the winnowings, first sieving means (18) arranged to sieve the output of the crushing means to separate out oversized particles, conveying means arranged to convey the oversized particles from the first sieving operation, and second sieving means (19) arranged to sieve the smaller fraction from the first sieving means to separate out acceptable product from tobacco dust; characterised in that said crushing means comprises a pair of rollers (11, 12), and a cutter device (23, 24) is interposed in said conveyor means from said first sieving means, to cut the oversized particles from the first sieving means, and the conveyor means carries cut particles therefrom directly back to the first sieving means. Apparatus according to Claim 2, characterised in that the rollers of the crushing means have a clearance between them of 0 to 1 mm. Apparatus according to Claim 3, characterised in that means (13, 14, 15, 16) are provided to drive the rollers of the crushing means in opposite directions. Apparatus according to any one of Claims 1 to 4, characterised in that the cutter device comprises overlapping steel disks (23, 24) arranged to be driven in opposite directions. Apparatus according to Claim 5, characterised in that the outer peripheries of the disks are cylindrical. Apparatus according to Claim 5, characterised in that the outer peripheries of the disks are serrated. Apparatus according to Claim 5, 6 or 7, characterised in that the outer peripheries of the disks are provided with cut-outs to assist conveying of the tobacco.

Inventors: VIGG, PETER
Applicants: AMF INCORPORATED
Application year: 1984
Main classification: A24B5
IPC codes: A24B5, B07B9, A24B3, B02C4, B02C18