Method and plant for treating tobacco leaves

Abstract

A method of treating tobacco leaves for separating the lamina from rib, includes: collecting the leaves in mannochi, and subjecting them to a shredder, where portions of the lamina of each leaf are torn from the remaining part of the leaf, separating portions of lamina from the remaining part of the leaf, by air, in at least one classification chamber, directly transferring portions of torn lamina to subsequent drying and packaging processes, passing the remaining parts of the leaf through a multi-stage beating line, in each of which progressive separation of portions of the lamina from the remaining part of the leaf is caused or to obtain at the exit of said beating line, an almost total separation of the lamina from the rib, transferring the separated portions of lamina to subsequent drying and packaging processes, transferring the pieces of rib exiting the beating line to the packaging.

Claims

1. A method of treating tobacco leaves for separation of leaf portions constituting lamina from leaf portions constituting ribs, comprising: placing bunches of leaves randomly on a feeding line of a shredder, in which flaps of the leaves are torn from a remaining part of the leaves, starting from edges thereof, separating with air in at least one classification chamber the flaps torn from the leaves in said shredder to form first flap portions of predominantly sole lamina and second flap portions of lamina attached to portions of rib, transferring said first flap portions directly to drying and packaging processes, passing the second flap portions through a line of beating in several stages, in each of which a progressive separation of portions of the lamina from remaining portions of lamina attached to portions of rib is caused, to obtain at an exit of said beating line an almost total separation of the lamina from the rib of the leaves, transferring the portions of lamina progressively separated from the portions of rib to the drying and packaging processes, and transferring the pieces of rib exiting the beating line to a further packaging process.

2. The method according to claim 1, wherein at least 30% of the lamina is removed by said shredder.

3. The method according to claim 1, wherein the tobacco leaves in said shredder are subjected to an action of a plurality of counter-rotating shaped discs at a same peripheral speed, partially interpenetrating and provided with teeth acting.

4. The method according to claim 3, wherein said shaped discs of said shredder are subjected to cyclic inversions of their direction of rotation.

5. The method according to claim 1, wherein the flaps exiting said shredder are subjected to a conditioning treatment to bring a moisture content of said flaps to an optimum humidity value for subsequent typing treatments.

6. The method according to claim 1, wherein the beating stages of the line of beating alternate with grading chambers.

7. The method according to claim 6, wherein the portions of lamina leaving the grading chambers are subjected to a drying treatment before transfer to the packaging process.

8. The method according to claim 1, wherein the rib portions coming out of said beating line are subjected to a drying treatment before transfer to the packaging process.

9. The method according to claim 1, wherein before introducing the tobacco leaves to be treated in said shredder, said leaves are subjected to a conditioning treatment to bring a moisture content of the leaves to an optimal value for subsequent treatments.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is further clarified hereinafter in some its preferred embodiments, reported for purely illustrative and non-limiting purposes with reference to the attached drawings, in which:

(2) FIG. 1 shows a general schematic view of a tobacco leaf treatment plant according to the invention,

(3) FIG. 2 shows a side view of the disruptor of the plant, and

(4) FIG. 3 shows a perspective view of the detail of the operating unit of the disruptor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) As can be seen from the figures, the tobacco leaf treatment plant according to the invention comprises one or more supply benches 2, in which the tobacco leaf mannocchi to be treated are placed.

(6) From these benches 2 the mannocchi are transferred by means of conveyor belts 4,6 to a first rotating conditioning cylinder 8, fed with jets of water and steam and subjected to the recirculation of air to increase the humidity of the tobacco leaves and bring them to a value of about 14-16%, which represents an optimal value to make them more flexible and therefore more suitable for subsequent treatments, to which they must be subjected.

(7) This first conditioning rotating cylinder 8 is traditional in itself and is not further described in its details.

(8) Since then the degree of humidity of the tobacco leaves to be treated can vary according to the country of production and the treatments to which they have been subjected previously, as well as the environmental conditions to which they were preserved before being subjected to this treatment, it may happen that they already have the optimal degree of humidity and that this first conditioning is not necessary. In this case the first conditioning cylinder 8, even if illustrated in the drawing, may not be present and the tobacco leaves can be directly transferred from the conveyor belt 6 to a disruptor 10 (Shredder).

(9) In the example described here, the first conditioner 8 is provided and the conditioned leaves that come out of it are transferred by means of a conveyor belt 12 to the disintegrator 10.

(10) The disintegrator 10 comprises an operating unit with two rotors, each formed by a plurality of shaped discs 14, mounted on a shaft 16, and spaced apart to an extent just greater than their thickness, so as to be able to partially penetrate with the discs 14 mounted on the other shaft 16. They have a shaped profile which highlights along their circumference of the teeth 18, hook-shaped and cooperating with corresponding teeth 18 present in the discs 14 mounted on the other shaft 16 and partially interpenetrating.

(11) The discs are preferably between 5 and 25 in number per linear meter of length of the shaft 16 which supports them and therefore each disc 14 has a thickness of between 40 mm and 200 mm. Furthermore, each disc 14 can have a diameter between 200 mm and 600 mm and can have from 2 to 10 teeth, which can preferably have a height between 30 mm and 50 mm.

(12) The two shafts 16 are associated with distinct motors or distinct transmission systems driven by the same motor; in any case, the two rotors are driven at the same peripheral speed but in opposite directions and are cyclically commanded to reverse their direction of rotation for the reasons which will become clear later.

(13) In the position above the operating unit formed by the two rotors with the shaped discs 14 there is a hopper 19 for loading the tobacco leaves to be treated and the two opposite longitudinal walls of this hopper extend below in comb elements 20 with inclined teeth and partially interpenetrating with the teeth 14 of the respective rotor in order to favor the conveyance of the tobacco leaves towards the rotor itself.

(14) The operating unit of the disruptor 10 is placed on a conveyor belt 22 which feeds the disintegrated material to a second conditioning rotating cylinder 24, similar to the first cylinder 8.

(15) This second conditioning cylinder 24 can preferably unload the product onto one or more benches 26, from which the product can be sent to first grading chambers 28, in which the free sheet parts are sent to a collection silo 30 and from this to a sheet collection line 32, while the rib parts, to which parts of the lamina are still joined, can be transferred to a traditional multi-stage beating line 34, alternating with grading chambers 35 for the complete separation of the lamina portions from the rib portions of the tobacco leaves.

(16) The plant is completed by a lamina drying unit 36, a dried lamina packing station 38, a rib drying unit 40 and a dried rib packaging line 42.

(17) The operation of the system described above is as follows:

(18) the tobacco leaf mannocchi to be treated are placed on the feeding benches 2 and from there they are transferred by means of the feeding belts 4,6 to the first conditioning rotating cylinder 8, in which they are brought to the optimum moisture content before being transferred to the disruptor 10.

(19) Here the bunches of tobacco leaves are subjected to the action of the counter-rotating discs 14, which with their teeth 18 break up the leaves and tear from these strips of lamina having the rough shape of squares with dimensions linked to the thickness of the discs themselves, to the shape of the teeth 18 and to the extent of interpenetration between the discs that form the two rotors; indicatively, the squares obtained can have dimensions of about 50 mm100 mm.

(20) This operation already leads to a separation of about 40% of the lamina from the remaining part of the leaf and this requires to subject only the remaining 60% of the product to beating, with considerable advantages both in the number of stages of the beating line and in the overall dimensions. of the equipment envisaged therein, and finally in the consumption of electricity.

(21) This 60% of product on which the separation of the lamina from the rib of the tobacco leaves is carried out is treated in the various stages of the beating line 34 in the traditional way, in the sense that in the classification chambers 35 located downstream of each beating stage it takes place the separation of the lamina (which is discharged into the lamina collection line 32, already fed with 40% of foils generated in the disruptor 10 and separated from the remaining part of the product in the classification chamber 28) from the remaining part of the product (which is started at the next typing stage).

(22) At the outlet of the beating line 34, therefore, only pieces of ribs are obtained, which are transferred to the drying unit 40 and from this to the packaging station 42, while the foils collected in all the various separation stages are transferred to the drying unit 36 and from this to the packing station 38.

(23) Finally, the dried and packaged sheets and ribs can be transferred to subsequent processing.

(24) From the aforegoing it is evident that the processing of tobacco leaves process according to the invention is greatly advantageous because: allows to eliminate all the personnel to pre-sorting of tobacco leaves and in particular approximately 50% of all personnel, with the same potential of the plant, eliminates all the dangers to personnel connected with the separation of the leaves that form the mannocchi and with the inevitable release of large quantities of dust, reduces the quantity of product to be subjected to beating with consequent reduction of at least 30% of the electrical energy absorbed by the beating line, it reduces the dimensions of the beating line to an extent that can be estimated up to 40%, it allows to obtain a product with a regular shape, with which to feed the packaging machines of cigarettes.