EP3079507B1

EP3079507B1 - Equipment for processing fibrous material

Info

Publication number: EP3079507B1
Application number: EP14802679.2A
Authority: EP
Inventors: Fré VAN DER LEEST
Original assignee: Theodorus Niemeyer BV
Current assignee: Theodorus Niemeyer BV
Priority date: 2013-12-09
Filing date: 2014-11-26
Publication date: 2018-08-29
Anticipated expiration: 2034-11-26
Also published as: GB201321714D0; AU2014361044B2; AU2014361044A1; GB2521011A; NZ720289A; WO2015086319A1; PL3079507T3; ES2696398T3; EP3079507A1

Description

Technical Field

This invention relates to equipment for processing of fibrous material, and in in particular to carding equipment.

Background

Carding equipment typically comprise a movable carding surface provided with an array of pins or needles fixed securely to a robust backing. Exposure of fibrous material to the surface disentangles the individual fibres and arranges them in alignment in a web or mat on the surface. Typically the carding surface forms the external surface of a rotatable cylinder or the surface of an endless belt. Conveyor belts are widely used to feed the fibrous material into and through the equipment.
DE 936 014 discloses an apparatus for processing tobacco including a delivery surface, a spiked roller, a moveable comb adjacent the spiked roller surface and a stripping roller for removal of tobacco from the spiked roller.

Summary

In equipment for processing fibrous material disclosed herein, a slide surface is provided in order to feed fibrous material into or through the equipment, whereby fibrous material delivered to an upper region of the surface traverses the slide surface under the influence of gravity to a lower region from which material may be removed by a suitable device, for example a carder or carding machine. The equipment for processing fibrous material, as defined in claim 1, comprises a feed device for feeding fibrous material from a reception region to a collection region, a carder having a movable carding surface arranged to gather fibrous carding surface, wherein the feed device comprises a slide surface that provides a path that extends downwardly and forwardly from the reception region to the collection region over which fibrous material delivered to the reception region traverses primarily under the influence of gravity into contact with the carder, and the carder is arranged to raise the fibrous material upwardly from the collection region towards the stripping device.
The carder comprises a carding cylinder and the slide surface is disposed substantially tangentially to the cylinder to form a constriction with the slide surface from which fibrous material accumulating in the constriction may be removed by rotation of the carding cylinder.
In order to facilitate removal of material, the collection region of the slide surface may be shaped so as to direct fibrous material upwardly on to the movable carding surface. For this purpose, the collection region may be provided with, for example, a ramp. In particular, the end region of the slide surface may be disposed generally tangentially to the carding surface and may include a ramp that directs fibrous material obliquely on to the carding surface.
In another embodiment, the movement of the material over the slide surface under the influence of gravity may be assisted by other mechanisms or systems. For example, the slide surface may be vibrated, or the movement across the slide surface may be assisted by the flow of air. In this respect, the slide surface of the feed device may include an outlet for example an air jet arranged to direct air over at least part of the slide surface to facilitate the movement of fibrous material over the surface.
In another embodiment, equipment for separating a stock of fibrous material into portions of a desired weight comprises a main feed system for creating a web of the fibrous material, a portioning mechanism for producing from the web major portions of a weight below the desired amount, a supplementary feed system for providing minor portions of fibrous material, and a combining system for combining the major portions and the minor portions to form final portions of the desired weight, and wherein the supplementary feed system comprises a carder having a movable carding surface on which a web of fibrous material may be formed, a stripping device arranged to remove fibrous material from the web to form the additional portions, and a feed device for feeding fibrous material to the carder, the feed device comprising a slide surface extending from a reception region to a collection region arranged such that, in use, fibrous material delivered to the reception region traverses the slide surface primarily under the influence of gravity into contact with the carder.
In another embodiment, equipment for processing fibrous material comprises
a feed device for transporting fibrous material in a forward direction along a path from a reception region to a collection region, a first carding cylinder mounted for rotation about an axis extending above and across the path and cooperating with the feed device to form a constriction in the path, a second carding cylinder mounted for rotation about an axis extending across the path and positioned above and rearwardly of the axis of the first cylinder, the cylindrical surfaces of the first and second cylinders being spaced radially to define a constriction corresponding to a desired web thickness of fibrous material, and a third cylinder mounted for rotation about an axis extending across the path and positioned forwardly of the axis of the first cylinder, the cylindrical surfaces of the first and third cylinders being spaced radially to enable the third cylinder to remove fibrous material from the first cylinder, wherein the feed device comprises a slide surface extending downwardly and forwardly from the reception region to the collection region, configured such that fibrous material delivered to the reception region traverses the surface primarily under the influence of gravity into contact with the first carding cylinder, and the first carding cylinder is arranged to raise the fibrous material upwardly from the collection region towards the third cylinder.
According to the present invention, a method of processing fibrous material, as defined in claim 8, comprises feeding fibrous material primarily under the influence of gravity in a path that extends downwardly and forwardly from a reception region to a collection region, forming a stack of the fibrous material in the collection region, raising fibrous material upwardly from the stack, carding the material raised from the stack to form a web thereof, transporting the web away from the collection region and stripping fibrous material from the web in a location downstream of the collection region.
A further embodiment comprises a method of separating a stock of fibrous material into portions of a desired weight comprising creating a web of the fibrous material; portioning the web into major portions of equal weight but below the desired weight; and combining the major portions with additional portions of fibrous material sufficient to make up the desired weight; wherein the additional portions of fibrous material are produced by feeding fibrous material under the influence of gravity in a path that extends downwardly and forwardly from a reception region to a collection region, forming a stack of the fibrous material in the collection region, raising fibrous material upwardly from the stack, carding the material raised from the stack to form a web thereof, transporting the web away from the collection region and stripping fibrous material from the web in a location downstream of the collection region to form the additional portions .

Brief Description of the Drawings

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which:

Figure 1 is a front view of equipment, party in vertical cross section, for processing fibrous material;
Figure 2 is a side view of the equipment of Figure 1;
Figure 3 is an exploded view of part of the equipment of Figures 1 and 2;
Figure 4 is a perspective view from above of a chute forming a component of the equipment of Figures 1 to 3;
Figures 4 a is a perspective view from below of the chute of Figure 4;
Figure 4 b is a perspective view from above of a deflector that is a component of the chute of Figure 4 a
Figure 5 is a perspective view from above and from one end of an alternative chute forming a component of the equipment of Figures 1 and 2;
Figure 6 is a perspective view from below of a component of the chute of Figure 5;
Figure 7 is a front view of part of the equipment of Figures 1 to 3 on an enlarged scale; and
Figure 8 is a schematic illustration of the geometry of part of the equipment of Figures 1 and 2.

Detailed Description

Referring to Figures 1 to 3 of the drawings, the equipment indicated generally at 1 is constructed to separate a stock 2 of fibrous material, in this case cut tobacco, into individual finished portions 3 that have substantially the same desired final weight, e.g. 50g or 100g, and are ready for packaging. The equipment 1 comprises the following main sub systems: (a) a main feed system indicated generally at 10, the function of which is to create a web 14 from the cut tobacco; (b) a portioning mechanism, indicated generally at 18, the function of which is to separate from the web 14 major portions 27 of cut tobacco of equal weight, but smaller in weight than the desired final weight by a desired amount (e.g. up to 6g lower in weight for a desired weight of 50g); (c) a supplementary feed system, indicated generally at 30, for providing minor portions 28 of cut tobacco having weights such that, when combined with the major portions, form finished portions 3 that have the desired weight; and (d) a combining system, indicated generally at 60, for combining the major portions 27 and the minor portions 28 to form final, finished portions 3 of the desired weight. A removal system, indicated generally at 70, transfers the finished portions 3 from the combining system 60 for further processing, for example packaging.
The main feed system 10 comprises a hopper 11 containing a stock 2 of cut tobacco, which is regularly replenished by a mechanism that is not illustrated in the drawings, but which is well known to those skilled in the art. Cut tobacco is withdrawn from the hopper 11 by means of a driven feed roller 12, the external cylindrical surface of which is provided with an array of radial pins. The pins cooperate with a comb 13 extending above and parallel to the axis of the feed roller 12 to form the web 14 of tobacco on the surface of the feed roller 12. The web 14 passes downwardly into a vertical shaft structure 15 of generally rectangular horizontal cross section. The shaft structure 15 is formed by two opposed fixed upright walls 16, 16 and two opposed continuous belts 17, 17 (best seen in Figure 2) each arranged over a set of drive rollers 5a-5d and 6a-6d so that the length of each belt between two adjacent, vertically spaced rollers 5a, 5b and 6a, 6b, together with the side walls 16,16, form a downwardly tapered shaft through which the web of tobacco 14 is driven by the belts 17.
The belts 17 urge the tobacco web 14 downwardly towards the portioning mechanism 18, which comprises two reciprocable combs 19 arranged to penetrate the web 14 and to divide it into discrete portions. The rate of reciprocation of the combs 19 and the density and rate of feed of the tobacco web 14 and the speed of operation of the belts 17 are controlled such that the individual portions at this stage are undersized, in that they contain marginally less that the desired amount of tobacco per portion (e.g. 40 or 45g rather than 50g in weight).
Two supplementary feed systems, indicated generally at 30, 30, on each side of the main feed system 10 are constructed to produce from the web of tobacco 14 additional, minor, portions 28 of tobacco which when combined with the major portions will make up the desired weight of the finished portions 3. The supplementary feed systems 30, 30 are of similar and symmetrical construction and, in the drawings, like parts thereof have been given the same reference numbers. The following description refers to the feed system 30 shown on the left in Figure 1, but the operation of the other feed system is the same. The fibrous material travels along separate paths through each of the supplementary feed systems in what will be referred to as a forward direction from the main feed system 10 to the combining system 60. References to upstream, downstream, rearward, forward and transverse in this context are intended to express directions relative to the direction of movement of the fibrous material along the relevant path.
In each of the supplementary feed systems 30, a supplementary supply drum 31 positioned above and on each side of the shaft structure 15 is arranged to contact one of the margins of the tobacco web 14 as it descends from the feed roller 12. The supplementary supply drum 31 is rotatable about its central axis in a reciprocating manner alternately clockwise and anticlockwise and carries combs extending axially along its external surface, so that, as it is reciprocated about its axis, it repeatedly extracts small quantities of the tobacco from the web 14 and directs them into an adjacent conduit 32, which is of rectangular transverse cross-section. The outlet of the conduit includes a wall 33 which shapes the outlet so as to direct the tobacco vertically downwards.
The extracted quantities of tobacco are fed by the conduit 32 into a housing 29 which encloses the other components of the supplementary feed system 30. As best seen in Figure 3, the housing 29 comprises a front panel 36 and a rear panel 37 which are mounted vertically within supporting framework of the equipment (omitted from the drawings for clarity) and spaced apart by a bottom panel 38 and a top panel 39. The bottom panel includes end walls 38a, 38b that extend between the lower parts of the front and rear panel defining therewith a discharge outlet 51 in one side of the housing and an access aperture 52 in the other side. The front panel 36 may be hinged and openable to allow access to the interior of the housing 29 for maintenance. The top panel 39 includes an aperture 33 through which the lower end of the conduit 32 projects to direct tobacco into the housing 29 and on to a chute 40, which is mounted between the front and rear panels, above the bottom panel 38 and below the top panel 39.
The chute 40 has an inclined slide surface 41 the upper region 41a of which defines a reception region on to which tobacco falls on leaving the outlet of chute 32. A lower region 41b of the chute 40 defines a collection region, in which the tobacco accumulates. The lower region 41b is disposed generally tangentially to a carding drum 45, which has a cylindrical carding surface provided with an array of pins. The carding drum 45 is mounted in the housing 29 for rotation about an axis A (Fig.7) and extends transversely across and above the slide surface 41, thereby forming a constriction in the path of the tobacco over the slide surface 41. Tobacco delivered to the upper region of the chute 40 thus traverses the slide surface under the influence of gravity in a non-vertical, downwardly-inclined, forwardly-extending path from the upper region 41a to the lower region 41b where it accumulates to form a loose stack 46 (Figure 7) lying in contact with the carding surface of the carding drum 45.
An optical sensor 58 is positioned on the rear panel 37 of the housing 29 to project a beam of light transversely over the surface of the lower region 41b of the chute. The sensor 58 is adjusted to a level in relation to the slide surface 41 of the chute 40 and the adjacent drums 45, 48 such that the beam of light will be interrupted if the stack of accumulated material becomes too large and, for example, would begin to interfere with the surface of the take-off drum. Interruption of the beam from the sensor deactivates the supplementary supply drum 31 so that further delivery of fibrous material to the chute 40 ceases. The supply drum is reactivated when the beam ceases to be interrupted. Typically in the equipment illustrated, the sensor 58 will normally also be positioned upstream from the carding drum 45, and the perpendicular distance p of the sensor from the slide surface of chute will be less than the closest perpendicular distance q between the slide surface 41 and the surface of the take-off drum 48.
The carding drum 45 comprises a hollow cylinder. The cylinder has an open end lying next to the front panel 36 of the housing 29 and a closed end carrying a bearing (not shown) which is connected to a drive motor mounted on the other side of the rear panel 37. The carding surface of the cylinder is provided with an array of radial pins and is rotated intermittently under the control of the combining system in a clockwise direction (as seen in the left hand side of Figure 1) about a horizontal axis shown at A in Figure 7. The pins 47 on the carding surface are inclined forwardly with respect to the radius of the carding drum in the direction of rotation of the drum (see Figure 8). As a result of rotation of the carding drum 45 in the clockwise direction as seen in Figure 1, the pins on the carding surface gather tobacco from the stack of fibres in the lower region 41b of the slide surface 41, directing the fibres rearwardly up the slide surface 41 and raising them upwardly away from the chute 40 to lie in a mat or web on the surface of the carding drum 45.
A take-off drum 48, also in the form of a cylinder with an array of pins on its external surface, is mounted on the rear panel of the housing 29 above the carding drum 45 and is rotatable in a clockwise direction (as illustrated in Figure 1) about an axis B (Figure 7) parallel to that of the carding drum 45, extending transversely across and above the slide surface 41 and lying rearwardly (i.e. upstream) of the axis A of the carding drum 45 with respect to the path of tobacco over the slide surface of the chute 40.
As best seen in Figure 7, the axes A and B of the carding drum 45 and the take-off drum 48 are so positioned that the surfaces of the two drums are spaced radially to define a constriction between the two drums. When the take-off drum is rotated in a direction contrary to the direction rotation of the carding drum, excess tobacco protruding above the pins on the carding drum 45 is removed by the pins on the take-off drum 48, thereby forming a web of more uniform thickness on the surface of the carding drum 45.
A rotatable brush 49 mounted on the rear panel 37 of the housing 29 adjacent the take-off drum 48 on the side remote from the carding drum 45 removes excess fibres from the take-off drum 48, which fall back on to the chute 40. The diameters of the two drums 45, 48 and the positions of their respective axes of rotation are such that the take-off drum 48 lies entirely to the upstream side of the vertical plane V (Fig 7) that includes the axis A of the carding drum 45. As a result, excess material from the take-off drum and the carding drum falls back on to the chute 40 and is not transported into the portioning mechanism.
As the carding drum 45 rotates, tobacco gathered from the stack 46 between the chute 40 and the carding drum 45 is elevated upwardly as a web on the surface of the carding drum 45 and travels along a circular path, initially readwardly and contrary to the direction of travel of the fibrous material down the chute, and then upwardly and forwardly over the top of the carding drum 45. The web is thus directed downstream towards a stripping device in the arranged to remove the fibrous material from the web. The stripping device comprises a stripping roller 50 which is mounted on the rear panel 37 of the housing 29 for rotation about an axis C (Figure 7). The axis C is parallel to the axis A of the carding drum 45 and positioned to the downstream side of the vertical plane V through the axis A of the carding drum 45, so that the stripping roller lies immediately adjacent the surface of the carding drum. The stripping roller 50 comprises a carding cylinder carrying an array of pins on its external surface and when, it is rotated at a speed greater than the carding drum 45, the pins remove the web from the surface of the feed roller 45 and separate it again into loose fibres. Because the stripping roller 50 lies forwardly (i.e. downstream) of the vertical plane containing the axis A of the carding drum 45 with respect to the path of tobacco over the slide surface of the chute 40, wholly to the downstream side of the vertical plane containing the axis A, all the material removed from the carding drum 45 falls through the discharge outlet 51 in the housing 29 and into the combining system 60. The aperture 51 is opened and closed by a pivotable flap 55 which is operated in synchrony with the movement of the components of the combining system 60 as described below to deliver minor portions of tobacco successively to the combining system 60.
The combining system 60 comprises a rotatable distributor drum 20 mounted beneath the outlet of the shaft structure 15, which has three pockets 20' on its external surface spaced circumferentially by 120°. Two weighing systems indicated generally at 24 are mounted on either side of and below the distributor drum 20. The weighing systems are of similar and symmetrical construction and, in the drawings, like parts thereof have been given the same reference numbers. The following description refers mainly to the weighing system shown on the left in Figure 1, but the operation of the right-hand weighing system is the same.
The weighing system 24 comprises a balance 21 having a balance arm 22 and a transfer drum 25 mounted thereon for rotation about an axis parallel to that of the distributor drum 20. The transfer drum has three pockets 25' on its external surface spaced circumferentially by 120°. The distributor drum 20 and the transfer drum 25 are configured so that, when a pocket 25' on the transfer drum is aligned vertically beneath the discharge outlet 51 in the housing 29 of the supplementary feed system 30, rotation of the distributor drum 20 brings a pocket 20' on the distributor drum into registry with the pocket 25' on the transfer drum 25 and the contents thereof fall under the influence of gravity into the pocket 25' of the transfer drum.
The operations of the weighing systems 24 are synchronised so that successive major portions of tobacco delivered from the main feed roller are weighed alternately in the left- and right-hand weighing systems. In an initial position, illustrated in Figure 1, the distributor drum 20 is arranged so that one of its pockets 20' is aligned with the outlet of the shaft structure 15, and the two transfer drums 25 are each arranged with one of their pockets 25' in vertical alignment with the discharge outlet 51 of the housing 29 of the adjacent supplementary feed system 30. When the distributor drum 20 receives a major portion of tobacco from the outlet of the shaft structure 15, the distributor drum 20 is rotated anti-clockwise (as seen in Figure 1) through 120°, into a position in which its contents discharge into and are received by the pocket 25' on the transfer drum 25 of the left-hand weighing system 24 as seen in Figure 1. The movement of the distributor drum 20 also brings an adjacent pocket 20'on its surface into alignment with the outlet of the shaft structure 15, to receive the next major portion of tobacco. The distributor drum 20 is then rotated 120° clockwise, bringing the adjacent pocket 20' into alignment with the upwardly-facing pocket 25' on the right-hand transfer drum 25, into which the portion of tobacco falls. The movement of the drum 20 in turn brings the first-mentioned pocket of the distributor drum into alignment with the outlet of the shaft structure, ready to receive the next portion 10, thereby completing a cycle of operation.
When a portion of tobacco is transferred from the distributor drum 20 to either of the transfer drums 25, the transfer drum 25 and its contents are weighed by the balance 21, which calculates the weight of the major portion of tobacco transferred. If the portion is underweight, the flap 55 in the housing of the supplementary feed system is opened, and the carding drum 45, stripping roller 50 and take-off drum 48 are activated. Tobacco removed from the carding drum 45 by the stripping roller 50 falls through the discharge outlet 51 of the housing 29 and into the cavity 25' of the transfer drum 21. The supplementary supply system continues to deliver tobacco until the balance 21 detects that the portion of tobacco received from the supplementary feed system, combined with the minor portion already present in the cavity 25', together form a portion having the desired weight. At that point, the supplementary supply system is stopped and the flap 55 is closed. The transfer drum 25 is then rotated 120° clockwise in order to discharge the weighed portion of tobacco into a removal system indicated generally at 70. This movement brings an adjacent empty pocket into vertical alignment with the discharge outlet 51 of the supplementary feed system, to receive the next major and minor portions of tobacco.
The removal system 70 comprises a transfer mechanism for receiving the weighed portions of tobacco alternately from the weighing systems 24,24 and delivering them successively to a conveyor system which removes the weighed portions for further processing.
The transfer mechanism comprises a hollow cylindrical housing 71 within which a generally planar rotor 73 is disposed diametrically for rotation about the central axis of the housing 71 in a clockwise direction as seen in Figure 1. Each tip of the rotor 73 carries an arcuate plate 74, extending circumferentially in the direction of rotation of the rotor 73 and conforming to the interior surface of the housing 71. The plates and the rotor thereby form within the housing two receptacles spaced circumferentially by 180° for receiving weighed portions of tobacco alternately from the two transfer drums 25. The housing 71 is provided with an upwardly facing inlet 76 positioned to register simultaneously with both the pockets of the transfer drums from which the weighed portions are discharged. A downwardly facing outlet 78 in the housing 71 is positioned vertically below the inlet 76. The rate of rotation of the rotor 73 is synchronised with the rate of rotation of the transfer drums 25 so that weighed portions of tobacco are deposited alternately in the two receptacles in the housing 71 by the right- and left-hand transfer drums 25.
The conveyor system comprises an endless chain of upwardly-open buckets 80 arranged for movement beneath the outlet of the housing 71 at a rate synchronised with the movement of the rotor 73 so that successive weighed portions emerging from the outlet 78 are received in separate buckets, which feed the next stage of the system, for example equipment for wrapping the weighed portions in individual packs.
The chutes 40, 40 of the equipment of Figures 1 and 2 are illustrated in more detail in Figures 4 to 6. Referring to Figures 4, 4 a and 4b, the chute 40 comprises a flat bottomed plate 400 having an upper surface 41 which when installed in the equipment of Figures 1 and 2 forms the slide surface over which the tobacco is transported from the duct 32 to the carding drum 45. The bottom plate may be formed from any material that is suitable for contact with the fibrous material that passes over the plate. In the case of cut tobacco a metal such as aluminium or steel, or a plastics material such as high density polyethylene may be used.
At the upper region 41a of the chute, the bottom plate 400 has an upper edge 404 chamfered at 45° to the upper surface 41. A top plate 406 is secured at one end to the upper edge 404 by two bolts (not shown). The top plate 406 is of L-shaped cross section and is positioned so that one surface of the top plate 406 extends upwardly from the bottom plate 400 and the other surface extends forwardly over the upper plate so that, when installed in the equipment, the top plate 406 catches tobacco from the duct 32 and directs it forwardly along a path of travel over the upper surface 41 towards the lower region 41b of the chute.
The chute 40 of Figure 4 is positioned in the housing 29 between the front and rear panels 36,37 of the housing 29, so that the panels lie against the sides of the top plate 406 and the sides of the bottom plate 400 to prevent tobacco fibres from falling laterally from the bottom plate as they traverse the plate.
Two opposed rails 409 are provided on the inner surfaces of the front and rear panels of the housing 29 to support the chute. The rails are of T-shape cross section complementary in shape to the grooves 408 along the sides of the bottom plate 400 so that the chute can slide into and out of the housing through the access aperture 52 for maintenance purposes. As illustrated in Figure 7, the position of the chute along the rails may be adjusted by a bolt 414 that interconnects a bracket 412 on the base of the bottom plate 400 with a bracket 416 on the front or rear panels 36, 37 of the housing 29.
A deflector 410 positioned in the lower region of the chute forms a ramp that extends transversely across the lower region 41b of the bottom plate. An upper surface 411 of the ramp extends forwardly and upwardly from the top plate 406 and terminates in an edge adjacent the surface of the carding drum 45. The effect of the ramp is illustrated schematically in Figure 8. In the lower region 41b, the slide surface 41 of the chute is inclined in the direction of the carding drum 45 downwardly with respect to the horizontal plane (indicated by the line VWX in Figure 8). The slide surface is aligned to extend substantially tangentially to the carding surface of the carding drum 45, as indicated by the line WZ in Figure 8, and therefore lies in a plane substantially at right angles to the radius of curvature R₁ of the carding surface at its closest point to the surface of the carding drum 45. The deflector 410 modifies the slope of the slide surface in the end region 41b so as to direct fibrous material along a path WY that extends obliquely or non-tangentially on to the carding surface, as indicated by the arrows in Figure 8. Thus, the end region of the slide surface 41 lies on a surface WZ that forms an approximate tangent to the carding surface, whereas the ramp lies on a surface WY that forms an obtuse angle P with the radius R₂ of the carding surface at its intersection with the carding surface.
As a result, when the chute is installed in the equipment, cut tobacco traverses the slide surface 41 predominantly under the influence of gravity to the lower region 41b and is directed upwardly by the deflector 410 towards and into contact with the surface of the carding drum 45. The deflector is particularly helpful in directing smaller fibres of cut tobacco on to the surface of the carding drum because the smaller fibres remain entrained with the larger fibres. In the absence of the deflector, smaller fibres tend to segregate from the larger particles and to build up in the housing beneath the carding drum.
The chute 40 is mounted in the housing 29 with the top plate 406 positioned so as to catch material from the duct 32 and to direct it downwardly over the bottom plate and at an angle such that he cut tobacco falls freely across the slide plate towards the carding drum 45. The angle of inclination of the chute (as indicated by angle H in Figure 8) may be selected such that the fibrous material traverses the slide surface of the chute freely, but not so quickly that the stack of tobacco accumulating in the constriction between the chute and the carding drum 45 exerts excessive pressure on the fibres, thereby causing attrition or damage to the fibres by the pins of the carding drum. The weight applied to the carding drum preferably lies in the region of 130 to 200 grams. By controlling the rate of delivery of the fibrous material to the carding drum, the amount of dust and fine particulate material produced can be controlled and significantly reduced compared to that produced by feed systems incorporating conveyor belts.
For cut tobacco, the angle of inclination H of the slide surface to the horizontal is typically at least 35°, or 40° and at most 45°, 50° or 60° and generally in the range from 35° to 55° to the horizontal, e.g. from 40° to 50°. Where a deflector is used, the obtuse angle P will normally not be greater than 180°, and may for example lie in a range with a lower limit of 110°, 115° or 130° and an upper limit of 160°, 135° or 130°.
In an alternative construction, illustrated in Figures 5 and 6, the chute 40 comprises a modified bottom plate 500, which comprises a base plate 502 similar to that of the chute illustrated in Figures 4 and 5, and an air distributor plate 504, which overlies the upper region of the bottom plate 500. The underside of the air distributor plate 504, illustrated in Figure 6, includes a V-shaped recess 506 in its lower region which extends from the lower edge 508 of the plate and tapers to an apex 510 positioned upwardly from the lower edge. The apex 510 of the recess overlies an air inlet aperture 515 in the base plate 502, which is adapted for connection to an air line (not shown) The recess 506 in the air distributor plate 504 cooperates with the base plate 502 to define an air outlet or jet that is arranged to direct air downwardly over the lower part of the base plate 502 thereby facilitating the movement of fibrous material over the slide surface of the chute 40.
The base plate 502 is connected to a top plate 406 and a deflector 410 similar in construction to those of the chute illustrated in Figure 4. In addition, the chute 40 is provided with side plates 516 and 518 which are secured to the base plate 502 by bolts. The upper ends 516a, 518a of the side plates lie against the upwardly extending surface of the top plate. The lower ends 516b, 518b of the side plate are arcuate and conform closely to the circumference of the carding drum 45 with which the chute engages when installed in the housing 29. The side plates 516, 518 prevent tobacco fibres from escaping from the chute 40.
An aperture 530 is provided in one of the side plates to permit the beam from the optical sensor 58 to pass over the slide surface of the chute. A reflector may be provided on the opposite wall to improve the intensity of light reflected back to the sensor 58.
The operation of the chute of Figures 5 and 6 is similar to that of Figure 4, save that pressurised air may be directed over the surface of the bottom plate through the air inlet and cut-away portion in order to assist the tobacco in its downward passage over the slide surface of the chute.
The use of downwardly-inclined, non vertical slide surfaces 41 in the feed device described above provides a significant improvement in the amount of contamination and waste in the form of fine particulate material that is generated during the operation of the equipment, as compared with equipment in which conveyor belts are used. The slide surfaces are not prone to deterioration in the same way as flexible surfaces of conveyor belts, and therefore lead to little, if any, contamination of the fibrous material during use even over a prolonged time. The slide surfaces also require much less maintenance and non-productive down-time for in the equipment than a conveyor belt, being essentially static installations with no moving parts.
Furthermore, where a conveyor is used, the fibrous material is driven positively into contact with the pins of the carder, which cause attrition and degradation of the fibrous material, particularly where material congregates in the narrowest part of the constriction formed between the conveyor and the carder. At this point, the fibrous material lies between two surfaces moving in opposite directions and therefore suffers severe attrition by the pins on the carding surface. Where a non-vertical inclined slide surface is used however, the fibrous material traverses the surface gently and is merely held in contact with the carding surface under its own weight. The material therefore suffers significantly less attrition by the carding surface before being picked up by the carder. During trials of the equipment described herein the amount of waste in the form of fine particles during operation of the equipment described herein was reduced by up to 0.6kg per hour as compared with the same system using conveyor feed, which represents a significant reduction in operating costs.

Claims

Equipment for processing fibrous material (2) comprising a feed device (30) for feeding fibrous material from a reception region (41a) to a collection region (41b); a carding cylinder (45) having a carding surface arranged to gather fibrous material from the collection region into a web on the carding surface; and a stripping device (50) arranged to remove fibrous material from the web on the carding surface, characterised in that the feed device comprises a slide surface (41) disposed substantially tangentially to the cylinder (45) that provides a path that extends downwardly and forwardly from the reception region (41a) to the collection region (41b) over which fibrous material delivered to the reception region traverses primarily under the influence of gravity into contact with the carding cylinder (45), and the carding cylinder is arranged to raise the fibrous material upwardly from the collection region towards the stripping device (50).
Equipment according to Claim 1 wherein the carder comprises a first carding cylinder (45) mounted for rotation about an axis (A) extending above and across the path and cooperating with the slide surface (41) to form a constriction in the path and a second carding cylinder (48) mounted for rotation about an axis (B) extending across the path and positioned above and rearwardly of the axis (A) of the first cylinder (45), the cylindrical surfaces of the first and second cylinders being spaced radially to define a constriction corresponding to a desired web thickness of fibrous material; and the stripping device (50) comprises a third carding cylinder mounted for rotation about an axis (C) extending across the path and positioned forwardly of the axis (A) of the first cylinder (45), the cylindrical surfaces of the first and third carding cylinders being spaced radially to enable the third carding cylinder to remove fibrous material from the first cylinder.
Equipment according to Claim 1 or Claim 2 wherein the reception region (41a) of the slide surface (41) is shaped so as to direct fibrous material upwardly on to the carding surface.
Equipment according to any one of Claims 1 to 3 wherein the end region of the slide surface (41) comprises a substantially planar surface extending tangentially to the carding surface and a ramp (410) having a surface inclined acutely to the planar surface to direct fibrous material obliquely on to the carding surface.
Equipment according to any one of Claims 1 to 4 wherein the feed device (30) further comprising an inlet (515) for the supply of compressed air and an outlet (506) on the slide surface (41) in communication with the inlet, the outlet being arranged to direct air across at least part of the slide surface to facilitate the movement of fibrous material over the slide surface.
Equipment according to any one of Claims 1 to 5 wherein the slide surface (41) extends downwardly at an angle of from 40 to 50 degrees to the vertical.
Equipment for separating a stock of fibrous material into portions of a desired weight comprising a main feed system (10) for creating a web (14) of the fibrous material, a portioning mechanism (18) for producing from the web into major portions (27) of a weight less than the desired weight, a supplementary feed system (30) for providing minor portions (28) of fibrous material, and a combining system (60) for combining the major portions and the minor portions to form final portions (3) of the desired weight, and wherein the supplementary feed system (30) comprises equipment according to any one of Claims 1 to 6.
A method of processing fibrous material characterised by feeding fibrous material to a carding cylinder (45) primarily under the influence of gravity in a path that extends downwardly and forwardly from a reception region (41a) to a collection region (41b), in a direction substantially tangential to the carding cylinder, forming a stack of the fibrous material in the collection region, raising fibrous material upwardly from the stack, carding the material raised from the stack to form a web thereof, transporting the web away from the collection region and stripping fibrous material from the web in a location downstream of the collection region.
A method of separating a stock of fibrous material into portions of a desired weight comprising creating a web (14) of the fibrous material; portioning the web into major portions (27) of equal weight but below the desired weight; and combining the major portions with additional portions (28) of fibrous material sufficient to make up the desired weight; wherein the additional portions of fibrous material are produced by a method according to Claim 8.