WO1997025885A1

WO1997025885A1 - Cigarette manufacture

Info

Publication number: WO1997025885A1
Application number: PCT/GB1997/000155
Authority: WO
Inventors: Walter Carascon; John Dawson; Derek Henry Dyett; Graham Foster Wright
Original assignee: Molins Plc
Priority date: 1996-01-20
Filing date: 1997-01-20
Publication date: 1997-07-24
Also published as: AU1315197A; GB9601230D0; JP2000503207A; CN1209730A; EP1006820A1

Abstract

A cigarette making machine includes an elongate tobacco reservoir (10; 110) arranged to receive pneumatically delivered tobacco at one end (10A), and to feed tobacco as a thick carpet towards the other end (10B) at which there is located one or more metering rollers (26, 28, 30) for feeding a thinner metered carpet (34) of tobacco towards a cigarette rod forming part of the machine, the reservoir having a width approximately equal to the width of the metered carpet fed towards the rod-forming device and having at its tobacco inlet an oscillating device (22; 122) for spreading the pneumatically delivered tobacco across the width of the hopper, and having means (36; 136) at each end for substantially sealing the space within the reservoir from the atmosphere, so that tobacco can be stored in the reservoir, while the machine is not operating, without drying to any significant extent.

Description

l Cigarette Manufacture

2

3 This invention is concerned with the feeding of tobacco to and in a cigarette making machine.

5 In a cigarette factory it is common to feed tobacco pneumatically

6 from a central primary unit to a number of cigarette making machines,

7 usually on an intermittent on-demand basis, though there have been s proposals for feeding tobacco from the primary unit continuously or 9 substantially so. Continuous feeding is desirable as it reduces the ιo velocity at which the tobacco must be fed and thus reduces tobacco n breakage, but it does impose design requirements on the primary unit i2 and also on the cigarette making machines. One aspect of the present i3 invention is concerned with a tobacco feed arrangement at the cigarette

H maker end which is capable of receiving tobacco continuously from a is primary unit, though it can also be used with a more stan dard i6 non-continuous primary unit. Some other aspects of this invention are i7 described below and in the appended claims. is According to one aspect of this invention, a cigarette making i9 machine includes an elongate tobacco reservoir arranged to receive

2o pneumatically delivered tobacco at one end, and to feed tobacco as a

2i thick carpet towards the other end at which there is located one or more

22 metering rollers for feeding a thinner metered carpet of tobacco towards

23 a cigarette rod forming part of the machine, the reservoir having a width u approximately equal to the width of the metered carpet fed towards the

25 rod-forming device and having at its tobacco inlet an oscillating device

26 for spreading the pneumatically delivered tobacco across the width of

27 the hopper, and having means at each end for substantially sealing the

28 space within the reservoir from the atmosphere, so that tobacco can be

29 stored in the reservoir, while the machine is not operating, without drying 0 to any significant extent. i With this arrangement, tobacco can be left in the reservoir while 2 the machine is not operating, for example between shifts, without drying 3 and thus becoming effectively unusable when the machine restarts. A However, the machine preferably includes provision for adding moisture 5 (for example, by means of steam) to the tobacco after it leaves the 6 reservoir and before it enters the rod-forming part of the machine. Thus, 7 if the tobacco does dry slightly in the reservoir or arrives at the cigarette 8 making machine in a slightly dry state, it can be brought to the optimal 1 moisture level for manufacture of cigarettes. The addition of moisture

2 may be made automatically in response to detection of the moisture level

3 in the tobacco feed system of the machine (for example, as it leaves the metering rollers), or by detection of the moisture level in the completed

5 cigarettes.

6 The provision of a relatively large, wide reservoir for tobacco in accordance with this aspect of the invention enables the machine to β continue running for a significant period of time (for example, up to three 9 minutes) in the event of the supply of tobacco from the primary unit ιo being interrupted. Moreover, if the machine stops as a result of a fault, ii rather than as part of a planned run down, then tobacco on its way to the i2 machine from the primary unit can be received in the reservoir and then i3 be retained there until the machine is restarted; for this purpose, the rate

IA at which tobacco is initially delivered into the reservoir during normal is operation is preferably controlled so that the reservoir becomes only ie partly full, thus allowing space for the in-transit tobacco when the

17 machine stops. A typical length of the pipe between a primary unit and a is cigarette maker is of the order of 20-30 metres. While the machine is in i operation, the delivery of tobacco into the reservoir is preferably

20 controlled so as to maintain the reservoir in an approximately

2i predetermined partly filled state, for example between half full and two

22 thirds full.

23 The sealing of the reservoir at its output end is preferably 2A achieved by a rotary air lock which, when the machine is operating,

25 allows the metered carpet of tobacco to pass through it while

26 hermetically isolating the spaces above and below it from one another.

27 Thus the air pressure in the reservoir and as far as the air lock can be

28 below atmospheric as a result of suction applied to the machine to draw 9 tobacco continuously (or nearly so) into the reservoir from the primary 0 unit, while the air pressure below the air lock may be atmospheric.

3i The reservoir may also be arranged to receive and store (and thus

32 prevent from drying out during the period between operating shifts of the

33 machine, for example overnight) tobacco from any one or more of the following sources: 5 1. Tobacco discharged from the garniture area of the 6 machine while the machine is being started up and before the tobacco is enclosed in a paper wrapper. 8 2. Tobacco recovered from other parts of the machine. 1 3. Tobacco recovered from rejected cigarettes, for

2 example by a recovery device which may be fitted to the cigarette

3 making machine.

A 4. Tobacco removed from the cigarette filler stream by

5 the usual trimming device; for example within the range 25% to 40% of

6 the filler stream.

7 Some of the above-mentioned returned tobaccos (and particularly s the trimmed tobacco) may, however, be re-fed back into an area of the machine where it combines with the metered carpet, thus bypassing the ιo reservoir. n Tobacco remaining in the maker following an abrupt stoppage i2 may also be fed out through the garniture when the machine re-starts. i3 A second aspect of this invention is concerned with a method of

IA making cigarettes in which tobacco is fed pneumatically and is substantially continuously from a primary unit to a number of cigarette i6 making machines each of which has an elongate reservoir arranged to i7 receive the pneumatically delivered tobacco at one end and to convey is the tobacco as a thick carpet towards one or more metering rollers, at ig the other end of the reservoir, arranged to feed a thinner metered carpet

20 of tobacco towards a cigarette rod forming part of the machine, the

2i capacity of the reservoir being sufficient to accommodate all the tobacco

22 in the tobacco-conveying duct between the primary unit and the

23 cigarette making machine in the event of the machine stopping, and 2A sufficient to enable the machine to keep running for a significant period

25 of time (e.g. a few minutes) in the event of the supply of tobacco from

26 the primary unit being temporarily interrupted. 7 The thick carpet of tobacco formed in the reservoir preferably has 8 approximately the same width as the thin metered carpet. This width 9 measurement corresponds to the width of the shower channel or 0 "chimney" through which, in the common type of cigarette making i machine (for example the Molins Mark 9, Mark 10 or Passim machine), 2 tobacco is showered upwards to form a cigarette filler stream on the 3 underneath surface of a suction band. The width is typically within the range 600mm to 1000mm. 5 Examples of cigarette making machines according to this 6 invention are shown in the accompanying drawings. In these drawings: 7 Figure 1 is a diagrammatic end view of the tobacco feed 8 arrangement of one machine; and i Figure 2 is a diagrammatic perspective view of another machine.

2 The machine shown in Figure 1 includes a reservoir 10 having an

3 inlet end 10A and an output end 10B. A conveyor band 12 forms the A floor of the reservoir, and the roof of the reservoir is formed by a

5 perforated or porous plate 14 forming one wall of a suction manifold 16.

6 During use, suction is applied to the manifold 16 through a pipe 18 and

7 this serves to draw tobacco into the reservoir via an inlet 20 connected to β a pipe (not shown) extending from a primary unit which is also not 9 shown. ιo Tobacco enters the reservoir through a feed device 22 which a oscillates about a vertical axis at its upstream end so as to spread the i2 tobacco across the entire width of the reservoir. The width of the i3 reservoir may, for example, be 800mm. The height of the reservoir

IA (distance between the conveyor 12 and wall 14) is 430mm and the is length of the reservoir in this particular example is approximately ie 2170mm. These dimensions are suitable, for example, for a machine i7 manufacturing cigarettes at a rate of 10,000 per minute. is A thick carpet of tobacco 24 forms in the reservoir and is driven i9 towards the output end 10B by the conveyor 12, which moves at a

20 greater speed than the carpet and is smooth so as to be able to slip with

2i respect to the tobacco carpet 24. At the output end 10B of the reservoir

22 tobacco is fed further by three pinned feed rollers 26,28,30 rotating in

23 the directions shown. The upper and lower feed rollers 26 and 28 2 remove tobacco from the advancing face of the carpet in the reservoir

25 and feed it between them and towards the roller 30, which loosens the

26 tobacco and delivers it onto a ramp 32. The feed rollers meter the

27 tobacco so that it is delivered onto the ramp 32 as a thinner carpet 34.

∑β A rotating air lock 36 at the lower end of the ramp 32 conveys the

29 carpet 28 onto a further ramp 38 while forming an air seal. For the latter

30 purpose the air lock 36 has vanes extending outwards towards part 3i cylindrical fixed casing members 40 and 42; the tips of the vanes move

32 with a small running clearance with respect to the casing members.

33 At the lower end of the ramp 38, the tobacco carpet is picked up 3A by a carded drum 44 which conveys the tobacco towards and past a

35 carded refuser drum 46. A roll of tobacco 48 forms between these two

36 drums and ensures that a very precisely metered carpet of tobacco is 7 conveyed past the refuser roll 46 by the carded drum 44. A conventional

38 picker roller (not shown) then removes the tobacco from the drum 44 1 and projects it along a plate 50 in a conventional manner (for example

2 described in our US patent No. 3443688). On leaving the plate 50, the

3 tobacco passes through a winnowing device and then up a chimney extending towards a suction band on which the showered tobacco forms

5 a cigarette filler stream in the conventional manner.

6 The moisture content of the tobacco is detected in the region of

7 the feed rollers 26-30 by a ceramic moisture sensor 52, for example one β available from Michell Instruments Ltd, Nuffield Close, Cambridge CB4 9 1 SS. When the sensor 52 indicates a need for the addition of moisture ιo to the tobacco, steam is injected through a number of steam inlets 54 π below the air lock 36. Alternatively, a fine water spray may be used. i2 Steam is, however, preferable since it also raises the temperature of the i3 tobacco; this effect may be enhanced by the use of super-heated

IA relatively dry steam. The ramp 38 and adjacent walls of the tobacco is feeder may be heated (e.g. to 100°C) to prevent condensation of steam i6 on them. i7 Waste, recovered and trimmed tobacco may be introduced into is the pipe leading from the primary unit to the inlet 20 to the reservoir. i9 Alternatively some or all of that tobacco may be fed directly back to the

2o tobacco carpet, bypassing the reservoir, via an inlet 56. For this

2i purpose, the tobacco may be drawn into the inlet by suction applied

22 from a suction manifold 58 through a perforated wall 60. The tobacco

23 returning through the inlet 56 drops onto a ramp 62 and slides down that 2 and onto the metered carpet of tobacco as it approaches the carded

25 drum 44. The moisture level of the tobacco returned through the inlet 56

26 may be controlled as a result of the steam introduced through the

27 nozzles 54, which raises the moisture level of the air in the vicinity of the

28 tobacco approaching and on the carded drum 44. One possibility is that trimmed tobacco and tobacco recovered 0 from rejected cigarettes may be returned via the inlet 56, while waste i tobacco may be returned via the inlet 20 to the reservoir. ₂ The inlet 56 may include an oscillating feed device (similar to the 3 device 22) to spread the tobacco across the width of the hopper. The A movement of the feed device may be modulated in response to optical 5 or other detectors sensing the height of the tobacco roll 48 at various 6 positions along the length of the drum 44, so as to maintain the roll 7 height substantially even. The average height of the roll is kept constant 8 by controlling the speeds of the feed rollers 26-30. 1 A magnet 64 is positioned above the ramp 32 to remove ferrous

2 foreign objects. Non-ferrous foreign objects may, for example, also be

3 detected while moving down the ramp 32 and may be removed by a horizontal air jet. Any foreign object which actually reaches the air lock

5 36 may be ejected by a servo device (not shown) swinging outwards the

6 member forming the casing wall 42, for which purpose the wall member

7 is mounted on an arm pivoted at 66. s The centre line of the cigarette making machine for which the

9 apparatus of Figure 1 constitutes a feeder or hopper is parallel to the axis ιo of the carded drum 44; that is to say, it is at right angles to the centre line a of the reservoir. Alternatively, the centre line of the reservoir may be

12 parallel to the centre line of the machine, such an arrangement being 13 shown in Figure 2. It will be understood that the centre line of the

IA machine is a line parallel to the continuous cigarette rod formed by the is machine. i6 Figure 2 shows a modified form of the tobacco feed arrangement i7 shown in Figure 1, together with some additional details, is In Figure 2, a reservoir 110 is shown which is generally similar to i9 the reservoir 10 in Figure 1. Air is drawn into the reservoir by means of

2o suction applied through a pipe 118 to a manifold mounted above the

2i reservoir and separated from the reservoir by a perforated plate or grill

22 114. Tobacco enters the reservoir through an oscillating feeder device

23 122 which spreads the tobacco across the width of the reservoir. At the 2A downstream (right-hand) end of the reservoir Figure 2 shows only two

25 feed rollers, but there may instead be three rollers as shown in Figure 1.

26 The metered carpet of tobacco fed from the reservoir drops, in this 7 example, onto a quadrant conveyor band 170 arranged to convey the 8 carpet along a curved path, through 90°, so that the eventual cigarette

29 rod will be parallel to the centre line of the reservoir 110. 0 Removal of ferrous foreign objects in this example is achieved by i means of a magnet arrangement 172 above the quadrant conveyor 170. 2 As in Figure 1 , a metered carpet of tobacco passes through a 3 rotary air lock 173 and then through a conditioning channel 174 in which steam is injected when and to the extent necessary to raise the moisture 5 level and also the temperature of the tobacco. 6 Waste tobacco from the garniture area of the machine is returned 7 via a pipe 176 leading into a pipe 178 carrying the tobacco from a 8 primary unit represented diagrammatically by the item 179. 1 The following arrangement is shown in Figure 2 for returning

2 trimmed tobacco and recovered tobacco. A suction manifold 158

3 (equivalent to the manifold 58 in Figure 1 ) forms part of a closed air circuit including a suction fan 178 which draws air out of the suction

5 manifold via a pipe 180.

6 A return pipe 182 delivers trimmed and recovered tobacco into a

7 space below a grill forming the bottom wall of the suction manifold 158. s As shown diagrammatically, trimmed tobacco is delivered into a lateral 9 inlet to a pipe 184, while recovered tobacco is delivered into an inlet to a ιo pipe 186. Both tobacco flows may be drawn in by venturi actions; they n then enter the pipe 182 and are returned into the hopper of the cigarette i2 making machine. i3 A cigarette making machine according to this invention may

IA include provision for separating long strands of tobacco from is medium-length and shorter strands, for example in the manner i6 described in our US patent No. 5,018,538 and possibly for the purposes i7 mentioned in that patent. In particular, tobacco strands which are too is long for ideal use in a cigarette making machine may be cut or broken in i9 such a feed unit. The feed unit may, in fact, simply serve to separate

20 long strands from shorter strands which pass directly into the tobacco

2i carpet while the long strands are subject to further processing so as to

22 be shortened. Very fine or dust-like particles of tobacco may be

23 automatically fed from the feed unit for delivery to a tobacco A reconstituting plant. 5 Stem extracted from the tobacco by the usual winnower passes 6 out of the machine through a pipe 188 and into a stem processing unit 7 190. The processed (finely cut) stem may be fed back into the machine 8 via the pipe 182. Water or steam may be injected into the pipe 182 through an inlet 0 1 89 to moisten the tobacco returned through if and to the extent i necessary. This means of adding moisture may be controlled so as to 2 obviate any need for adding moisture also in the channel 174. 3 As already mentioned, the tobacco feed arrangement described in A Figure 1 or Figure 2 may be used in conjunction with a continuous or 5 substantially continuous feed arrangement from the primary unit. The 6 primary feed unit (shown diagrammatically as 179 in Figure 2) may, for 7 example, be one of those described in our US patent No. 4491138. Near s the primary unit 179 the pipe 178 may include a flap which opens 1 automatically to let in air and stop the pipe from sucking up more

2 tobacco when the cigarette making machine stops. Suction continues to

3 be applied to the pipe 118 until all the tobacco in the pipe 178 has been A drawn into the reservoir. Valves 118A and 178A may then be closed to 5 seal the reservoir and prevent any significant loss of moisture from the

6 tobacco in the reservoir until the machine re-starts. It will be understood

7 that the sealing of the reservoir is completed at the output end by s appropriate casing members around the conveyor 170. Also, while the

9 machine is stationary, the drive to the air lock 173 (which may be ιo independent) is also stopped. a The waste tobacco in either of the above examples may include i2 tobacco recovered from areas of the machine in which it has caused a i3 tobacco choke, for example in the region of the chimney through which

IA tobacco is showered to form a cigarette filler stream. Such tobacco may is be re-fed into the reservoir or may be returned together with trimmed ie tobacco. Tobacco removed during the winnowing process may also be i returned in the same manner.

18 19 20 21 22 23 2A 25 26 27 28 29 30 31 32 33 3A 35 6 7 38

Claims

Claims:

1. A cigarette making machine including an elongate tobacco reservoir (10; 110) arranged to receive pneumatically delivered tobacco

5 at one end (10A), and to feed tobacco as a thick carpet (24) towards the

6 other end (10B) at which there is located one or more metering rollers

7 (26,28,30) for feeding a thinner metered carpet of tobacco (34) towards β a cigarette rod forming part of the machine, the reservoir having a width approximately equal to the width of the metered carpet (34) fed towards ιo the rod-forming device and having at its tobacco inlet an oscillating a feeder (22; 122) for spreading the pneumatically delivered tobacco i2 across the width of the hopper, and having means at each end for i3 substantially sealing the space within the reservoir from the atmosphere

IA so that tobacco can be stored in the reservoir, while the machine is not is operating, without drying to any significant extent.

16 i7 2. A machine according to claim 1 , in which the reservoir has is a bottom wall formed by a conveyor band (12) by which the thick carpet i9 of tobacco (24) in the reservoir is conveyed towards the feed roller or

20 rollers (26,28,30).

21

22 3. A machine according to claim 2, in which the conveyor

23 band has a smooth top surface and slips with respect to the carpet of 2A tobacco (24) in the reservoir.

25 6 4. A machine according to any one of claims 1 to 3, in which 7 the sealing of the reservoir at its output end is achieved by a rotary air 8 lock (36; 173) which, when the machine is operating, allows the metered carpet of tobacco (34) to pass through it while hermetically isolating the 0 spaces above and below it from one another. 1 2 5. A machine according to claim 4, in which the air pressure in 3 the reservoir and as far as the air lock is below atmospheric as a result of A suction applied to the machine to draw tobacco into the reservoir. 5 6 6. A machine according to claim 5, in which the suction is 7 transmitted through a suction manifold (16) which extends along the top 8 of the reservoir and is separated from the reservoir by an air-permeable wall (14).

2

3 7. A machine according to any one of claims 1 to 6, including means (52) for detecting the moisture content of the tobacco, and

5 means (54; 189) for adding moisture to the tobacco when necessary.

6

7 8. A machine according to claim 7, in which the tobacco s moisture is detected in the region of the feed roller or rollers (26-30).

9 lo 9. A machine according to claim7 or claim 8, in which ii moisture is added to the tobacco, when necessary, where it moves as a i2 metered carpet.

13

I 10. A machine according to claims 4 to 9, in which the moisture is is added to the metered carpet downstream of the air lock (36).

16 i 11. A machine according to any one of claims 7 to 10, in which ie the addition of moisture is by means of steam.

19

20 12. A machine according to any one of claims 1 to 1 1 ,

2i including means (176) for feeding into the reservoir (1 10), together with 2 the main flow of fresh tobacco entering the reservoir waste, tobacco 3 recovered from the machine or from rejected cigarettes and/or tobacco removed from the cigarette filler stream by a trimmer.

25 6 13. A method of making cigarettes, in which tobacco is fed 7 pneumatically and substantially continuously from a primary unit to a 8 number of cigarette machines each of which has an elongate reservoir 9 arranged to receive the pneumatically delivered tobacco at one end and 0 to convey the tobacco as a thick carpet towards one or more metering i rollers, at the other end of the reservoir, arranged to feed a thinner 2 metered carpet of tobacco towards a cigarette rod forming part of the 3 machine, the capacity of the reservoir being sufficient to accommodate all the tobacco in the tobacco- conveying duct between the primary unit 5 and the cigarette making machine in the event of the machine stopping, 6 and sufficient to enable the machine to keep running for a significant 7 period of time in the event of the supply of tobacco from the primary unit β being temporarily interrupted. 1 14. A cigarette making machine according to claim 1 and

2 substantially in accordance with any one of the examples described in

3 the foregoing specification.

A

5 15. A method of making cigarettes according to claim 13 and

6 substantially in accordance with any one of the examples described in 7 the foregoing specification.

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19 0 1 2 3 A 5 6 7 8 9 0 1 2 3 A 5 6 7 8