METHOD FOR PRODUCING A PLANT-BASED SHEET

Abstract

The invention relates to a method for producing a plant-based material sheet comprising: providing a plant-based powder material and a cellulose-based sheet-forming agent, determining a moisture content of the plant-based material, mixing the plant-based powder material, the cellulose-based sheet-forming agent and an amount of water to form a slurry, drying the slurry to form the plant-based sheet, wherein the amount of water added for slurry formation is calculated based on the determined moisture content of the plant-based powder material. Such a method allows the adjustment of the amount of water added for slurry formation based on the determined moisture content of the plant-based powder material.

Claims

1. A method for producing a plant-based material sheet comprising: providing a plant-based powder material and a cellulose-based sheet-forming agent, determining a moisture content of the plant-based material, mixing the plant-based powder material, the cellulose-based sheet-forming agent and an amount of water to form a slurry, drying the slurry to form the plant-based sheet, wherein the amount of water added for slurry formation is calculated based on the determined moisture content of the plant-based powder material.

2. The method according to claim 1, wherein the slurry has a predestined target water content range and wherein the amount of water added for slurry formation is calculated so that the slurry reaches a water content within the predestined target water content range.

3. The method according to claim 1, wherein a plant material moisture detector is employed for determining the moisture content of the plant-based material, preferably wherein the plant material moisture detector in one of a microwave detector or an infrared detector.

4. The method according to claim 3, wherein the plant-based powder material is dispersed on a conveyor belt and wherein a radiation emitter of the plant material moisture detector is positioned on one side of the conveyor belt and a radiation receiver of the plant material plant material moisture detector is positioned on an opposing side of the conveyor belt for radiation of the plant material plant material moisture detector to pass through the plant-based powder material.

5. The method according to claim 1, wherein the plant-based powder material comprises tobacco powder.

6. The method according to claim 1, wherein the plant-based powder material is adjusted to a particle size of between 20 m to 200 m.

7. The method according to claim 1, wherein a particle size of the plant-based powder material is determined.

8. The method according to claim 1, wherein a water flow rate controller is employed, wherein the flow rate controller controls the amount of the water added for slurry formation based on the determined moisture content of the plant-based powder material.

9. The method according to claim 1, wherein the cellulose-based sheet-forming agent comprises cellulose fibers, and a water/cellulose fibres pulp is prepared and mixed with the plant-based powder material.

10. The method according to claim 1, wherein the predestined target water content range of the slurry is between 55 weight percent to 85 weight percent water.

11. The method according to claim 1, wherein the slurry is dried to form the plant-based sheet, wherein the plant-based sheet has a moisture content of between 7 percent and 15 percent of dry weight of the sheet.

12. The method according to claim 1, wherein the slurry has a predestined target water content range and wherein a sum of the determined moisture content of the plant-based powder material and the amount of water added for slurry formation results in a water content of the slurry being within the target water content range.

13. The method according to claim 12, wherein a moisture content of the cellulose-based sheet-forming agent is determined and wherein a sum of the determined moisture content of the plant-based powder material, the amount of water added for slurry formation and the moisture content of the cellulose-based sheet-forming agent results in a water content of the slurry being within the target water content range.

14. An apparatus configured for producing a plant-based material sheet, the apparatus comprising a mixing tank including a stirrer, the mixing tank configured for mixing a plant-based powder material and a cellulose-based sheet-forming agent for forming a slurry, a plant material moisture detector configured for determining a moisture content of the plant-based powder material, a water flow rate controller configured for providing water to the mixing tank, wherein the water flow rate controller is further configured for providing an amount of water to the mixing tank for slurry formation, wherein the amount of water is calculated based on the determined moisture content of the plant-based powder material, and a drying device for drying the slurry to form the plant-based sheet.

15. The apparatus according to claim 14, comprising an open loop control system, the open loop control system configured for adjusting a pump speed of the flow rate controller based on the determined moisture content of the plant-based powder material.

16. The method according to claim 5, wherein the plant-based powder material is tobacco powder and wherein the material sheet is a sheet of an aerosol-forming substrate.

17. The method according to claim 7, wherein the particle size of the plant-based material is determined before determining the moisture content of the plant-based material.

18. The method according to claim 9, wherein the water/cellulose fibres pulp comprises cellulose fibres having a mean length of between 0.2 millimetres and 4 millimetres.

Description

[0099] The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

[0100] FIG. 1 shows a schematic drawing of an embodiment of an apparatus for producing a plant-based material sheet comprising a plant material moisture detector; and

[0101] FIG. 2 depicts a more detailed schematic drawing of a radiation emitter and a radiation receiver of the plant material moisture detector in relation to the plant-based powder material whose moisture content is to be determined.

[0102] In the following elements with the same functionality are marked with the same reference numerals throughout all the figures.

[0103] FIG. 1 shows a schematic drawing of one embodiment of an apparatus 30 for producing a plant-based material sheet. Preferably, this apparatus 30 is configured for producing a tobacco-based material sheet for forming an aerosol-forming substrate.

[0104] The apparatus 30 includes a conveyor belt 14 for transporting plant-based powder material 10 to plant-based powder material hopper 15. A plant material moisture detector 12 is present. This plant material moisture detector 12 is configured for determining a moisture content of the plant-based powder material. The plant material moisture detector 12 is connected to a flow rate controller 26. This flow rate controller 26 is able to determine the amount of water to be added for slurry formation based on the determined moisture content of the plant-based powder material. The flow rate controller 26 can control the water inlet 20 in order to control the overall quantity of water added for slurry formation. This water inlet 20 is part of the first delivery line 20A for the water to be added for slurry formation and for delivery of the cellulose-based sheet-forming agent. A second delivery line 22A is present which is controlled by a separate water inlet 22. This second delivery line 22A delivers the thickening agent, for example guar and an aerosol-former to the mixer 18 for slurry formation. The plant-based powder material hopper 15 transports the plant-based powder material to a silo 16A for storage via a first conveyor belt 17A. The plant-based powder material is then further transported by a second conveyor belt 17B to a mixer 16B which finally transports the plant-based powder material to the slurry mixer 18. The mixer 16B may receive the plant-based powder material and a quantity of water in order to produce a mixture of the plant-based powder material and water. This mixture can then be added to the slurry mixer 18. In the slurry mixer 18 the plant-based powder material is mixed with the water quantity determined by the flow rate controller, the cellulose-based sheet-forming agent and with the thickening agent and the aerosol-former for slurry formation. Such an apparatus allows the water flow rate of the water to be added for slurry formation to be adapted based on the calculated moisture content of the plant-based material which was determined via the plant material moisture detector 12.

[0105] FIG. 2 depicts a schematic drawing of a plant material moisture detector 12 with a radiation emitter 12A and a radiation receiver 12B. Microwave radiation indicated by the dashed lines is emitted by the radiation emitter 12A of the plant material moisture detector 12. This emitted microwave radiation passes through plant-based powder material 10 located on the conveyor belt 14 and is received by the radiation receiver 12B. This microwave radiation which passed through the plant-based powder material can be employed in order to calculate the moisture content of the plant-based powder material. The moisture in the plant-based powder material will cause an attenuation and a phase shift of the microwave radiation passing through the material. A comparison of the microwave radiation received by the radiation receiver and of the microwave radiation emitted by the radiation emitter allows a determination of the overall attenuation and phase shift of the microwave radiation owing to the interaction of the microwave radiation with both the plant-based powder material and the moisture content of the material. The flow rate controller 26 includes a module 26A for the calculation of the moisture content and a module 26B for communication between the data processing unit and the plant material moisture detector 12. The communication module 26B can communicate with a modem 32 for communication. This modem 32 can further communicate with the data processing unit 34. This data processing unit is also configured for controlling the apparatus configured for producing the plant-based material sheet. A conveyor belt compensating device 36 can be present which is able to generate a compensating signal due to any incidental absorption of the microwaves by the material of the conveyor belt. The compensating device may provide a compensating signal in the range of 4 milliampere to 20 milliampere. The arrow denoted with 1 shows a communication line for the amplitude attenuation. The arrow denoted with 2 shows a communication line for phase shift. These two communication lines provide further information about the amplitude attenuation and the phase shift which is only caused by the plant-based powder material, but not by the moisture content of the material. This allows the module 26A for the calculation of the moisture content to correctly determine the amplitude attenuation and the phase shift of the microwave radiation which is only caused by the moisture, not by the plant-based material itself. This allows an accurate determination of the moisture content of the plant-based powder material.