METHOD FOR DETERMINING AN ADDITIVE CONTENT IN A TOBACCO PAPER FOR ELECTRIC CIGARETTES

Abstract

A method is provided for measuring an additive content in a tobacco paper for electric cigarettes produced from a pulpy mass of additives, water, flavoring substances and tobacco that is dried to form a tobacco paper having a single-layer. The method includes measuring the tobacco paper using at least one microwave resonator having two resonance modes with two resonant frequencies (f.sub.L, f.sub.H). A lower of the two resonant frequencies (f.sub.L) is in a range that is less than 1 GHz and a higher of the two resonant frequencies is in a range that is more than 2 GHZ. A density-independent moisture value (?.sub.L,H) is determined for each of the two resonance modes and a glycerol content (g) is determined depending on two moisture angles.

Claims

1-14. (canceled)

15. A method for measuring an additive content in a tobacco paper for electric cigarettes produced from a pulpy mass of additives, water, flavoring substances and tobacco that is dried to form a tobacco paper having a single-layer, comprising: measuring the tobacco paper using at least one microwave resonator having two resonance modes with two resonant frequencies (f.sub.L, f.sub.H), wherein a lower of the two resonant frequencies (f.sub.L) is in a range that is less than 1 GHz and a higher of the two resonant frequencies is in a range that is more than 2 GHZ; determining a density-independent moisture value (?.sub.L,H) for each of the two resonance modes; and determining a glycerol content (g) depending on two moisture angles.

16. The method according to claim 15, wherein the additives at least partially comprises glycerol.

17. The method according to claim 15, wherein a content (g) of the additives depends linearly on both density-independent moisture values (?.sub.L,H) and an offset value.

18. The method according to any one of claim 17, further comprising measuring a moisture content for the tobacco paper depending on the density-independent moisture value (?.sub.L,H) at the higher resonant frequency.

19. The method according to claim 17, comprising determining the content (g) of the additives independently of a mass of the tobacco paper.

20. The method according to claim 15, wherein the at least one microwave resonator comprises a planar sensor.

21. The method according to claim 15, wherein the at least one microwave resonator comprises a gap sensor.

22. The method according to claim 15, wherein the measuring the tobacco paper takes place at the single-layer.

23. The method according to claim 15, wherein the measuring the tobacco paper takes place at a point where the tobacco paper has been wound up into a bobbin.

24. The method according to claim 15, wherein the measuring the tobacco paper takes place in or immediately downstream of a dryer.

25. The method according to claim 15, wherein the measuring the tobacco paper takes place upstream of a crimping apparatus.

26. The method according to claim 15, further comprising adding an amount of at least one of water and glycerol to the pulpy mass takes place depending on at least one density-independent moisture value.

27. The method according to claim 15, further comprising: providing a moisture angle (?) as the moisture value; and determining the moisture angle as a quotient of a broadening of a full width at half maximum (B) and a resonant frequency shift (A), wherein an empty and a filled resonator are compared with one another in each case.

28. The method according to claim 15, further comprising providing a moisture angle (?) as the moisture value, wherein the moisture angle results as an arc tangent of a quotient of a broadening of a full width at half maximum (B) and a resonant frequency shift (A).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The method according to the invention will be further explained below with reference to an exemplary embodiment.

[0018] FIG. 1 schematically depicts locations for glycerol measurement in the primary.

[0019] FIG. 2 schematically depicts possible locations for the glycerol measurement in the crimper.

[0020] FIG. 3 illustrates the measured values for the moisture angle of two modes depending on the moisture and glycerol content.

[0021] FIG. 4 graphically illustrates results of the glycerol measurement.

DETAILED DESCRIPTION OF THE INVENTION

[0022] FIG. 1 schematically illustrates a mixer 10, in which glycerol is mixed with water, binder, flavoring substances, further aerosol-forming additives and tobacco to form a pulp for use in electric cigarettes. The exemplary embodiment is based on glycerol, but other additives with or without glycerol may also be used and measured in the same way. Here, the ingredients are added in precisely defined ratios and processed in the mixer into a homogeneous mixture in the form of a pulp. The pulp formed in this manner is rolled in a rolling machine 12 and fed to the dryer 14 as a flat material. The drying process takes place in the dryer 14, during which an undefined amount of water and glycerol is lost from the tobacco paper. The dried tobacco paper is rolled up into a bobbin in 16. Possible measuring stations MP for monitoring the moisture content and measuring the glycerol content are located, for example, in the dryer 14, along the route of the dried tobacco paper from the dryer 14 to the bobbin 16 and directly at the bobbin 16. The values obtained for the glycerol content and/or moisture content can be fed back to the mixer 10 in order to adjust the glycerol content to a desired value. It is also possible to adjust the moisture content. The measured values can also be used to adapt the parameters of the drying process to the desired values for moisture and glycerol.

[0023] FIG. 2 shows, in a schematic view, how tobacco paper 18 is unwound from the bobbin 16 in the transport direction T. The tobacco paper is fed to a crimper 20 via transport rollers 18. Paper 22 for rod wrapping is also fed to the crimper 20 in order to be formed into a rod in the region 24. The possible measuring stations MP are located along the route from the bobbin to the crimper 20, to which further paper is fed for forming a rod.

[0024] FIG. 3 shows the plotted moisture values (moisture content in %) over the moisture angle ? for two frequencies with 0.9 GHZ and 5.6 GHz. The moisture angle ? is formed as the arc tangent of the quotient of B/A, wherein A describes the resonant frequency shift and B describes the broadening of the resonance curve. The measurements were performed at a different glycerol content and different moisture content. The second measurement was taken at the same material for the higher frequency.

[0025] The measurement at 5.6 GHz shows that the moisture angles ? are independent of the glycerol content of the samples and only depend on the moisture content thereof. This results from the proportionality of the moisture angle and moisture content at a different glycerol content. Therefore, the regression line plotted in FIG. 3 can be used as a calibration for a glycerol-independent moisture measurement.

[0026] In contrast, the measurement at 0.9 GHz shows that the measured moisture angles ? depend on the moisture and glycerol content. The samples with the same glycerol content are denoted in the figure by separate linear regressions. To compensate for the influence of the variation in the material moisture content, the moisture angles ? of both frequencies must be taken into account for the measurement of the glycerol content.

[0027] FIG. 4 shows the result of the evaluation, wherein the reference value for the glycerol content has been plotted against the measured glycerol value. The calculation takes place using the moisture angles ? of both frequencies in the calibration equation explained below. The good match between the values and the regression line can be clearly seen, with the measured values deviating by only a few percent from the reference values.

[0028] The measured value of the resonance mode with the high frequency PH is used for the measurement of the moisture content. One approach for the moisture value u is as follows:

[00001]$u=a_1.Math.{?}_H+a_2$

wherein a.sub.1, a.sub.2 represent calibration coefficients here. If the calibration coefficients are determined, the moisture value can be determined directly from the measured moisture angle ?.sub.H.

[0029] The moisture angle of both modes is used to determine the glycerol content:

[00002]$g=b_1.Math.{?}_L+b_2.Math.{?}_H+b_3$

[0030] wherein b.sub.1, b.sub.2 and b.sub.3 are the calibration coefficients. It is important here that both moisture angles are included in the determination of the glycerol content as a mass-independent variable and thus the measurement of moisture and glycerol content is independent of the mass of the measured product. The mass fraction of the measured product, determined as in the prior art via a possibly overdetermined system of equations, impairs the measurement accuracy. The additional determination of the proportion of tobacco cannot take place in the approach according to the invention, which is based on mass-independent measurands.