METHOD FOR MANUFACTURING A VENTILATION ZONE IN AN AEROSOL-GENERATING ARTICLE

Abstract

The invention relates to a method for manufacturing a first ventilation zone in a first aerosol-generating article and a second ventilation zone in a second aerosol-generating article, comprising the method steps: A) providing a first aerosol-generating article, B) forming first perforations in the first aerosol-generating article, thereby creating a first ventilation zone, C) determining the first air infusion value for the first aerosol-generating article, the air infusion value being determined by the equation (P.sub.inP.sub.out).Math.100%/P.sub.in, wherein P.sub.in is the air pressure applied at the first end face of the article and P.sub.out is the air pressure detected at the second end face of the article, D) comparing said first air infusion value to a reference value, E) providing the second aerosol-generating article and forming second perforations in the second aerosol-generating article, thereby creating the second ventilation zone, wherein a size of the second perforations is adjusted based on the comparison between the determined first air infusion value and the reference value.

Claims

1-15. (canceled)

16. A method for manufacturing a first ventilation zone in a first aerosol-generating article and a second ventilation zone in a second aerosol-generating article, comprising the method steps: A) providing a first aerosol-generating article, B) forming first perforations in the first aerosol-generating article, thereby creating a first ventilation zone, C) determining the first air infusion value for the first aerosol-generating article, the air infusion value being determined by the equation (P.sub.inP.sub.out).Math.100%/P.sub.in, wherein P.sub.in is an air pressure of between 5 millibars and 50 millibars applied at the first end face of the article and P.sub.out is an air pressure detected at the second end face of the article, D) comparing said first air infusion value to a reference value, E) providing the second aerosol-generating article and forming second perforations in the second aerosol-generating article, thereby creating the second ventilation zone, wherein a size of the second perforations is adjusted based on the comparison between the determined first air infusion value and the reference value, wherein during method step C) an air blast is applied as air pressure to the first aerosol-generating article for a time period of between 25 milliseconds to 60 milliseconds and the pressure difference is measured between both opposing first and second end faces of the first aerosol-generating article as indicated by the equation above.

17. The method according to claim 16, wherein a first continuous rod is provided as a first aerosol-generating article and wherein a second continuous rod is provided as a second aerosol-generating article, wherein the first continuous rod and the second continuous rod includes at least two aerosol-generating articles, preferably wherein the first continuous rod and the second continuous rod consists of two aerosol-generating articles.

18. The method according to any claim 16 for manufacturing a first ventilation zone in a predetermined first number of first aerosol-generating articles, wherein during the method steps A) and B) the predetermined first number of first aerosol-generating articles is provided and wherein first perforations are formed in each of the first aerosol-generating articles of the predetermined first number of first aerosol-generating articles and wherein during method step C) the individual first air infusion values of the first aerosol-generating articles are determined and wherein an average first air infusion value thereof is calculated.

19. The method for manufacturing according to claim 16, wherein the reference value is a target air infusion value for the first and second aerosol-generating article.

20. The method for manufacturing of claim 16, wherein in a method step A2) before method step B) a first resistance-to-draw RTD value of the first aerosol-generating article is measured in accordance with ISO 6565-2015, more preferably wherein the RTD value is measured by applying a constant air flow to the first end face of the first aerosol-generating article and measuring the increase in air pressure at said first end face of the first aerosol-generating article due to the air resistance of the article.

21. The method according to claim 18, wherein individual first RTD values are determined for each of the first aerosol-generating articles of the predetermined first number of first aerosol-generating articles.

22. The method for manufacturing according to claim 21, wherein the individual first air infusion values of the first aerosol-generating articles determined in step C) are corrected on the basis of the first individual resistance-to-draw (RTD) values, thereby providing corrected individual first air infusion values and wherein an average corrected first air infusion value is calculated based on the corrected individual first air infusion values.

23. The method of manufacturing according to claim 22, wherein in step E) the average corrected first air infusion value is compared to the reference value and wherein in step E) the size of the second perforations is adjusted based on the comparison between the average corrected first air infusion value and the reference value.

24. The method according to claim 23, wherein an average first RTD value is calculated from the individual first RTD values of the first aerosol-generating articles and wherein an average second RTD value is calculated from individual second RTD values of the second aerosol-generating articles of the predetermined second number of first aerosol-generating articles.

25. The method according to claim 24 wherein the reference value is set in method step D) depending on the RTD value measured for the first aerosol-generating article in method step A2).

26. The method for manufacturing an aerosol-generating article of claim 18, wherein the predetermined first number of aerosol-generating articles is the same as the predetermined second number of aerosol-generating articles, preferably wherein the predetermined first and second number of aerosol-generating articles is at least 50, preferably at least 100, more preferably at least 1000 aerosol-generating articles.

27. The method of manufacturing according to claim 16, wherein in step E) the size of the second perforations is one of decreased or increased in comparison to the size of the first perforations.

28. The method for manufacturing of claim 16, wherein during method step B) slits or ovals are formed as first perforations, the first perforations having a width and a length, and wherein during method step E) the length of the second perforations is adjusted.

29. The method for manufacturing of any claim 16, wherein during method step A) a first aerosol-generating article is provided, wherein the first aerosol-generating article comprises a first hollow tube section and a first substrate section, preferably wherein the first aerosol-generating article further comprises a first filter section.

Description

[0144] The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

[0145] FIG. 1 shows a flow chart of one embodiment of a method of the present invention;

[0146] FIG. 2 depicts a flow chart of another embodiment of a method of the present invention also involving the calculation of the RTD value;

[0147] FIG. 3 depicts a schematic cross-sectional view of a continuous rod including two individual aerosol-generating articles with ventilation zones produced according to the present invention;

[0148] FIG. 4 depicts a schematic view of one single perforation of a ventilation zone produced according to the present invention.

[0149] FIG. 5 depicts a graph showing the compensation factor for the conversion of an air infusion value of an aerosol-generating article measured during the method of manufacturing the ventilation zone and the respective air infusion value determined in the laboratory.

[0150] FIG. 6 shows a graph depicting the correlation between the RTD value of a double stick and the target air infusion value of the ventilation zones to be manufactured in the double stick in order to obtain a desired air infusion value of 50 percent for the individual articles after cutting of the double stick.

[0151] In the following the same elements are marked with the same reference numerals throughout all the figures.

[0152] FIG. 1 depicts a flow chart of one embodiment of the present invention. In a method step A) a first continuous rod, in particular including two individual first aerosol-generating articles without any ventilation zone is provided as indicated by the box titled assembled stick. In the second method step B) first perforations are generated in the aerosol-generating article, in particular in its first hollow tube section as indicated by the box titled perforations. This can be done for example by employing a laser. In the third step C) the first air infusion value for the continuous first rod, including two individual first aerosol-generating articles is determined as shown in the box titled air infusion measure (on double stick). In the next step D) the air first infusion value is compared to a reference value (box titled air infusion within targets). If the measured first air infusion value is below or above the reference value, then the perforation parameters of the laser are adapted. The size of the second perforations within the second ventilation zone of the subsequently processed second aerosol-generating article in particular their length are increased or decreased in the subsequent method step E) in order to obtain a second aerosol-generating article with a new second air infusion value which is closer to the reference value, as indicated by the box titled perforation parameters are adapted (length of the slits).

[0153] FIG. 2 depicts a flow chart of another embodiment of the method of the invention. This embodiment of the method of the present invention includes the same method steps A), B), C), D) and E) as the method described above in FIG. 1. Additionally, this embodiment of the invention comprises a method step A2) before method step B) wherein individual first RTD values of a predetermined first plurality of first aerosol-generating articles are measured and wherein the average thereof is determined (box titled RTD calculation). Method step D) then both includes the application of an RTD correction factor based on the average of the RTD values determined in method step A2) to the air infusion values determined in method step C) and the comparison of this RTD corrected value with the reference value (boxes denoted RTD correction factor applied to measure and box titled air infusion within targets).

[0154] FIG. 3 depicts a schematic cross-sectional view of a first continuous rod 11 including two separate individual first aerosol-generating articles 10, thereby forming a double stick. Such a double stick may be typically employed by the method of the present invention in order to produce two first ventilation zones in the double stick. A second continuous rod may include the same components and the same aerosol-generating articles as the first continuous rod. These individual first aerosol-generating articles 10 can be generated from the first continuous rod 11 by cutting the continuous rod along the dashed line 10A. The two individual aerosol-generating articles 10 are connected to each other via their respective mouth end filter elements 20. These mouth end filter elements 20 are adjacent to the hollow tube section 14, which consists of the hollow support element 16 and the aerosol-cooling element 18. This hollow tube section 14 is adjacent to the substrate section 22 in the individual aerosol-generating articles 10, wherein each substrate section 22 contains of susceptor 24. This substrate section 22 is flanked in each aerosol-generating article by the filter element 26. In the continuous rod two first ventilation zones 12 have been formed during the method step B) of the present invention in the hollow tube sections 14 of each individual first aerosol-generating article. The air infusion value of such a first continuous rod 11 can be measured by applying a certain pressure to the first end face 11A of the rod and determining the air pressure having passed through the rod at the second end face 11B of the rod. The air pressure measured at the second end face 11B of the rod will be lower than the air pressure applied the first end face 11A, because air has passed through the perforations of the ventilation zones 12 reducing the air pressure.

[0155] The length of such a double stick may be 90 millimeters. Consequently, the length of the individual aerosol-generating articles after cutting of the double stick may be 45 millimeters. The diameter of the double stick may be 7.25 mm.

[0156] FIG. 4 shows a schematic view of one individual perforation 12A of the larger ventilation zones 12 depicted in FIG. 3. The perforation 12A has an oval shape with a width 13 and a length 15. Preferably, during method step E) of the method of the present invention only the length 15 is increased in order to better adapt the measured air infusion value to the reference value.

[0157] FIG. 5 shows a graph indicating the compensation factor for correcting the air infusion value determined during the method for manufacturing the ventilation zone based on the RTD value in order to obtain the respective air infusion value under laboratory conditions at constant airflow. The graph was obtained by fitting a curve into the respective individual values indicated by the black dots. The graph shows that for an RTD value of the double stick of around 60 mm Wg the compensation factor is around 5 percent. For an RTD value of the double stick of around 100 mmWg the correction factor would be 0. For high RTD values of the double stick of around 140 mmWg the correction factor would be around 2 percent.

[0158] FIG. 6 shows a graph depicting the correlation between the RTD value of a double stick and the respective air infusion value of the double stick which should be set as a reference value in order to obtain individual aerosol-generating articles with a desired air infusion value of 50 percent after cutting the double stick. The graph shows that the correlation between the air infusion of the double stick and the resulting air infusion of the individual aerosol-generating article after cutting off the double stick depends on the resistance to draw value of the double stick.