Method for producing ventilation zones in an aerosol-generating article - Patent Application 20070123633

Abstract

The present invention relates to a method for producing 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 of A) providing a first aerosol-generating article; B) forming a first perforation in the first aerosol-generating article, thereby creating a first ventilation zone; and C) determining a first air injection value for the first aerosol-generating article, the air injection value being determined according to the formula (P in -P out )·100% / P in where P in is the air pressure applied to the first end surface of the article, and P out is the air pressure detected at the second end face of the article; D) the method steps of comparing the first air injection value with a reference value; and E) the method steps of providing a second aerosol-generating article and forming a second perforation in the second aerosol-generating article, thereby creating a second ventilation zone, wherein a size of the second perforation is adjusted based on a comparison of the determined first air injection value with the reference value.

Description

[Technical field]

[0001] The present invention relates to a method for producing a ventilation zone in an aerosol-generating article.The aerosol-generating article may include an aerosol-forming substrate and may be adapted to generate an inhalable aerosol upon heating. [Background technology]

[0002] Aerosol-generating articles are known in the art in which an aerosol-forming substrate, such as a tobacco-containing substrate, is heated rather than burned.Typically in such heated smoking articles, aerosol is generated by transferring heat from a heat source to a physically separated aerosol-forming substrate or material, which may be located in contact with, within, around, or downstream of the heat source.During the use of the aerosol-generating article, volatile compounds are released from the aerosol-forming substrate by heat transfer from the heat source and are entrained in the air drawn through the aerosol-generating article.As the released compounds cool, they condense to form an aerosol. Summary of the Invention [Problem to be solved by the invention]

[0003] Aerosol-generating articles are known that have ventilation zones that include perforations. These ventilation zones allow ambient air to enter the aerosol-generating article during a user's puff. This allows for better mixing of the airflow coming from the aerosol-forming substrate with the ambient air to facilitate the formation of an aerosol. The amount of air that may enter the aerosol-generating article during a user's puff depends on the number, location, and shape of the perforations. These perforations can be difficult to form with low variability during a high-speed manufacturing process of the aerosol-generating article.

[0004] Bulk aerosol-generating articles that include ventilation zones can be difficult to manufacture without significant variations in important characteristics of the aerosol-generating article, such as the amount of air that can enter the aerosol-generating article through the ventilation zone. Differences in the properties of the aerosol-forming substrates of the bulk aerosol-generating articles that are manufactured can also cause differences in the properties of the aerosol-generating article.

[0005] In order to produce an aerosol-generating article that can operate efficiently and at high speed, it would be desirable to provide a method for producing a ventilation zone within an aerosol-generating article that provides an aerosol-generating article with low variability in air injection values ​​from one article to another.

[0006] It is also desirable to provide a method for producing ventilation zones in different aerosol-generating articles, which different aerosol-generating articles exhibit comparable characteristics. [Brief description of the drawings]

[0007] [Figure 1] 1 shows a flow diagram of one embodiment of the method of the present invention. [Diagram 2] 1 shows a flow chart of another embodiment of the method of the present invention, which also includes the calculation of the RTD value. [Diagram 3] 1 shows a schematic cross-sectional view of a continuous rod containing two individual aerosol-generating articles having ventilation zones made in accordance with the present invention. [Figure 4] FIG. 2 shows a schematic diagram of one single perforation in a ventilation zone made according to the present invention. [Diagram 5] 1 shows a graph illustrating compensation factors for conversion of air injection values ​​of an aerosol-generating article measured during a method of manufacturing a ventilation zone, and the respective air injection values ​​determined in a laboratory. [Figure 6]1 shows a graph illustrating the correlation between the RTD value of the double stick and the target air injection value of the ventilation zone produced with the double stick to obtain a desired air injection value of 50 percent for individual articles after cutting of the double stick. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] According to one aspect of the invention, there is provided a method for producing a first ventilation zone in a first aerosol-generating article and a second ventilation zone in a second aerosol-generating article. The method may include method step A) of providing a first aerosol-generating article. The method may also include method step B) of forming a first perforation in the first aerosol-generating article, thereby creating a first ventilation zone. The method includes a step of forming a first air injection value according to the formula (P in -P out )·100% / P in C) determining a first air injection value for the aerosol-generating article, the first air injection value being determined by the formula: in is the pressure applied to the first end surface of the article, P out is the air pressure detected at a second end surface of the article. The method may include method step E) of providing a second aerosol-generating article and forming a second perforation in the second aerosol-generating article, thereby creating a second ventilation zone, the size of the second perforation being adjusted based on a comparison of the determined first air injection value with a reference value.

[0009] According to a further aspect of the present invention, there is provided a method for producing a first ventilation zone in a first aerosol-generating article and a second ventilation zone in a second aerosol-generating article, comprising a method step A) of providing a first aerosol-generating article. The method also comprises a method step B) of forming a first perforation in the first aerosol-generating article, thereby creating the first ventilation zone. The method comprises a step of forming a first air injection value in accordance with the formula (P in -P out )·100% / P inC) determining a first air injection value for the first aerosol-generating article, the first air injection value being determined by the formula: in is the pressure applied to the first end surface of the article, P out is the air pressure detected at the second end surface of the article. The method also includes method step D) of comparing said first air injection value with a reference value. Also included is method step E) of providing a second aerosol-generating article and forming a second perforation in the second aerosol-generating article, thereby creating a second ventilation zone. The size of the second perforation is adjusted based on the comparison of the determined first air injection value with the reference value in method step E).

[0010] This method for producing ventilation zones may enable the production of aerosol-generating articles having more uniform first and second perforations within the first and second ventilation zones. This may provide aerosol-generating articles with low variability in air injection values ​​between the first and second aerosol-generating articles. This may provide a plurality of aerosol-generating articles where the individual aerosol-generating articles within the plurality of aerosol-generating articles have low variability in air injection values. This method may provide a means to control changes in air injection values ​​during the production of large quantities of aerosol-generating articles and provide aerosol-generating articles with more uniform air injection values ​​around a reference value.

[0011] The second ventilation zone in the second aerosol-generating article may be produced immediately after the formation of the first ventilation zone in the first aerosol-generating article. This may provide direct feedback regarding the air injection value produced in the first aerosol-generating article for the formation of the second perforations that create the second ventilation zone in the second aerosol-generating article. This may provide an air injection value that is more uniform between the first ventilation zone in the first aerosol-generating article and the second ventilation zone in the second aerosol-generating article.

[0012] Air infusion usually refers to the amount of air that can be drawn into an aerosol-generating article through its ventilation zone when a user pulls on the article during a puff. However, the amount of air that enters an aerosol-generating article during a user's puff is difficult to determine during a high-speed manufacturing process of the aerosol-generating article. Therefore, the method for manufacturing a ventilation zone of the present invention uses a different approach, where a constant air pressure is applied to a first end face, and the air pressure at a second end face of the article is determined as shown by the above equation for air infusion value. This allows for a similar evaluation of the air infusion value that is more compatible with high-speed manufacturing processes.

[0013] During method step C), an air blast may be applied to a first end face of the first aerosol-generating article. A pressure difference between the first end face and a second opposing end face of the first aerosol-generating article may be measured. In particular, the pressure applied to the first end face may be compared to the pressure of air leaving the first aerosol-generating article through the second opposing end face, as shown by the above formula.

[0014] The first continuous rod may be provided as a first aerosol-generating article. The second continuous rod may be provided as a second aerosol-generating article. The first and second continuous rods may comprise at least two aerosol-generating articles. The two aerosol-generating articles may preferably be connected to each other. This may form a "double stick" or "double aerosol-generating article". The first and second continuous rods preferably each consist of two aerosol-generating articles. Two single first aerosol-generating articles and two single second aerosol-generating articles may be produced from these continuous rods by cutting the rods in the middle, thereby producing two single aerosol-generating articles. Producing larger continuous rods of aerosol-generating articles may simplify the manufacturing process.

[0015] The two first ventilation zones may be produced in a first continuous rod comprising two first aerosol-generating articles. Similarly, the two second ventilation zones may be produced in a second continuous rod comprising two second aerosol-generating articles. This ensures that ventilation zones are produced in all aerosol-generating articles of the continuous rod. In a further embodiment, the method is for producing a first ventilation zone in a predetermined first number of first aerosol-generating articles. During method steps A) and B), a predetermined first number of first aerosol-generating articles may be provided and a first perforation may be formed in each of the first aerosol-generating articles of the predetermined first number of first aerosol-generating articles. During method step C), individual first air injection values ​​of the first aerosol-generating articles may be determined and an average first air injection value may be calculated.

[0016] This may allow for large scale production of a given number of the first aerosol-generating articles.

[0017] Further, the method may be for producing a second ventilation zone in a second predetermined number of second aerosol-generating articles. During method step E), a second predetermined number of second aerosol-generating articles may be provided. A second perforation may be formed in each of the second aerosol-generating articles of the second predetermined number of first aerosol-generating articles, thereby generating a second ventilation zone in the second predetermined number of second aerosol-generating articles. The second perforations may be formed based on a comparison of the determined average first air injection value with a reference value.

[0018] The method may allow for the fabrication of a multiple, predetermined number of second ventilation zones based on an average first air injection value determined from the fabrication of the first ventilation zones.

[0019] The first predetermined number of first aerosol-generating articles may be at least 50, preferably at least 100, more preferably at least 1000 first aerosol-generating articles. The first predetermined number of first aerosol-generating articles may be identical to the second predetermined number of second aerosol-generating articles. This may allow the production of a large number of first and second ventilation zones, each of the multiple first and second aerosol-generating articles having first and second air injection values ​​that are adjusted to the target air injection value.

[0020] The reference value may be a target air injection value for the first and second aerosol-generating articles, which allows for the production of first and second ventilation zones in the first and second aerosol-generating articles, the respective first and second air injection values ​​being adjusted to the target air injection value. The target air injection value may be a target air injection value for the first and second continuous rods.

[0021] The air injection value may be different for a single first aerosol-generating article and for a first continuous rod containing two aerosol-generating articles. The air injection value of a single first aerosol-generating article or a continuous rod may be expressed as a percentage value and may be between 30 percent and 80 percent, preferably between 40 percent and 60 percent, between 45 percent and 55 percent. These percentage ranges of air injection values ​​are acceptable for producing aerosol-generating articles with acceptable air injection values.

[0022] Preferably, the target air injection value may be set at between 40 percent and 60 percent, more preferably 50 percent, for a single aerosol-generating article.

[0023] The air pressure applied to the first aerosol-generating article at the first end face during method step C) for determining the first air injection value may be applied at a constant air pressure. The air pressure applied to the first aerosol-generating article at the first end face may be between 5 mbar and 50 mbar, preferably between 10 mbar and 30 mbar, more preferably between 15 mbar and 18 mbar. This may provide a quick and easy way to determine the air injection value of the aerosol-generating article during the production of the ventilation zone.

[0024] The air blast may be applied through a nozzle having a diameter of 1.6 to 2.0 millimeters, preferably 1.8 millimeters.

[0025] In particular, a 17 millibar air blast may be applied at a constant pressure to a first end surface of a first aerosol-generating article to determine a first air inlet value. The first air inlet value may be determined at a temperature of 22 degrees Celsius, a pressure of about 101 kilopascals, and a relative humidity of about 50 percent to 60 percent, preferably 60 percent. The duration of the air blast application may be between 25 milliseconds and 60 milliseconds.

[0026] The method for manufacturing the first and second ventilation zones in the first and second aerosol-generating articles may be controlled externally to the manufacturing process of the ventilation zones, for example in a laboratory. In an external control process, the air injection value may be determined at a constant air flow. This may differ from the determination of the air injection value during the manufacturing process, which may be performed at a constant air pressure. Due to different measurement methods, the air injection value determined during the manufacturing of the ventilation zones at a constant air pressure may differ from the air injection value of the aerosol-generating article determined in a laboratory at a constant air flow. This may require converting the air injection value determined "controlled" to a constant air pressure during the manufacturing process to the respective air injection value determined in a laboratory at a constant air flow.

[0027] Conversion between air injection values ​​determined during manufacturing of the ventilation zone at constant air pressure and air injection values ​​determined in the laboratory at constant air flow may be performed by applying a conversion factor, which may depend on the resistance to draw (RTD) of the aerosol-generating article.

[0028] Unless otherwise specified, the resistance to draw (RTD) of a component or an aerosol-generating article is measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the entire length of the component. The terms "pressure drop" or "draw resistance" of a component or article may also refer to "resistance to draw." These terms generally refer to measurements in accordance with ISO 6565-2015 being performed successfully under test at a temperature of about 22 degrees Celsius, a pressure of about 101 kPa (about 760 Torr), and a relative humidity of about 60%, with a volumetric flow rate of about 17.5 milliliters per second at the output or downstream end of the component being measured.

[0029] The RTD values ​​may vary during the manufacturing process of the ventilation zone of the aerosol-generating article due to some variability in the tobacco used in the aerosol-forming substrate between different aerosol-generating articles manufactured. These different RTD values ​​may also affect the air injection values ​​of each of the aerosol-generating articles.

[0030] In method step A2) prior to method step B), a first resistance to draw RTD value of the first aerosol-generating article may be measured. The resistance to draw value may be measured by applying a constant air flow to a 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. The air flow may have a pressure of up to 2500 mbar, preferably 2100 mbar, directed through a nozzle having a diameter of 0.2 millimeters.

[0031] Further, an individual first draw resistance value may be determined for each first aerosol-generating article of a predetermined first number of first aerosol-generating articles.

[0032] Preferably, individual first withdrawal resistance values ​​are determined for a predetermined first number of first continuous rods, each of which may contain two first aerosol-generating articles interconnected therewith.

[0033] The pull resistance of the first such continuous rod is 30 mm H 2 O~H 160mm 2 It may be O.

[0034] The first individual air injection value of the first aerosol-generating article determined in step C) at constant air pressure may be corrected based on the first individual RTD value. This may provide a corrected individual first air injection value. These RTD corrected individual first air injection values ​​may correspond to respective air injection values ​​measured in a laboratory at constant air flow. This may allow a comparison of the first air injection value determined in method step C) during the manufacture of the first ventilation zone with the air injection value determined in a laboratory at constant air flow.

[0035] In particular, a first compensation factor may be calculated taking into account the determined first RTD value. This first compensation factor may be determined taking into account the first RTD value measured for a first continuous rod containing two first aerosol-generating articles connected together, also referred to as a "double stick". The compensation factor may be experimentally determined for different aerosol-generating articles depending on the RTD values ​​of the articles. An example of the determination of the compensation factor is shown in FIG. 5.

[0036] The compensation factor may be a percentage factor and may depend on the RTD value determined for the first continuous rod. The compensation factor may be between -20 percent and +20 percent, preferably between -8 percent and +4 percent. The compensation factor may be applied to the respective first air injection value determined in method step C) during the production of the first ventilation zone. This may result in either subtracting or adding a certain percentage to the first air injection value determined during production at constant air pressure to obtain the respective air injection value obtained in the laboratory at constant air flow.

[0037] In method step E) of one embodiment of the method of the present invention, the average corrected first air injection value may be compared with a reference value. Furthermore, in step E), the size of the second perforation may be adjusted based on the comparison of the average corrected first air injection value with the reference value. This may make it possible to adjust the size of the second perforation based on air injection values ​​obtained in a laboratory at constant air flow.

[0038] During method step D), a delta value may be calculated. The delta value may be the difference between the average corrected first inflation value and a reference value. In method step E), the size of the second perforations may be adjusted based on the delta value.

[0039] The delta value may be 0 if the average corrected first air injection value is the same as the reference value. According to one embodiment of the method for producing a ventilation zone of the present invention, if the delta value is other than 0, the size of the second perforations may be adjusted in method step E). In another embodiment of the method for producing a ventilation zone of the present invention, the size of the second perforations may be adjusted in method step E) only if the delta value is above a certain threshold value. For example, the size of the second perforations may be adjusted only if the delta value is below or above a value between -0.5 percent and 0.5 percent, preferably the delta value may be preferably between -0.3 percent and 0.3 percent, preferably between -0.2 percent and 0.2 percent. Delta values ​​within the described ranges may not result in an adjustment of the size of the second perforations. A negative delta value may indicate that the average corrected first air injection value of the first predetermined number of first aerosol-generating articles is below the reference value. A positive delta value may indicate that the average corrected first air injection value of the first predetermined number of first aerosol-generating articles is above the reference value.

[0040] In method step E), the size of the second perforations may be either reduced or increased compared to the size of the first perforations.

[0041] In particular, the size of the second perforation may be increased compared to the size of the first perforation when the corrected first air injection value is smaller than the reference value, and the size of the second perforation may be decreased compared to the size of the first perforation when the corrected first air injection value is larger than the reference value.

[0042] During method step B), slits or ellipses may be formed as first perforations. These first perforations may have a width and a length in the first aerosol-generating article. During method step E), the length of the second perforations in the second aerosol-generating article may be adjusted. In particular, during method step E), only the length of the second perforations may be adjusted, maintaining the same width as the first perforations. The adjustment may be made by one of increasing or decreasing the length of the second perforations compared to the length of the first perforations depending on the delta value.

[0043] First and second aerosol-generating articles having first and second air injection values ​​that are too high or too low may also be rejected from the production stream, particularly first and second aerosol-generating articles having air injection values ​​outside the range of 30 percent to 80 percent.

[0044] One or more of the first and second perforations may have a non-circular cross-section. One or more of the first and second perforations may be slit-shaped or may have an elliptical cross-section. One or more of the first and second perforations may have an ellipticity, which is the ratio of the major diameter of the perforation divided by the minor diameter of the perforation, preferably at least 1.5, preferably at least 2, preferably at least 3, more preferably at least 4, and most preferably at least 5.

[0045] During one or both of method steps B) and E), a laser device may be used to form first and second perforations in the first and second aerosol-generating articles, or to adjust the size of the second perforations compared to the first perforations.

[0046] In method step E), the laser device can be used to adjust the size of the perforations by changing the "duty cycle set point" of the laser. The "duty cycle" of the laser device is the ratio between the period during which the laser is active and creating the perforations in the ventilation zone and the total time of the cycle for creating the perforations. The higher the "duty cycle", the longer the laser is active and the longer the length of the perforations.

[0047] In method step E), a second air injection value for the second aerosol-generating article may be determined. Further, individual second air injection values ​​for the second aerosol-generating articles of a predetermined second number of second aerosol-generating articles may be determined and an average of these individual second air injection values ​​may be calculated.

[0048] In method step E), a second resistance to withdrawal RTD value of the second aerosol-generating article may be measured. When second perforations are formed in the second aerosol-generating articles of a predetermined second number of the first aerosol-generating articles, an individual second RTD value may be determined for each of the second aerosol-generating articles.

[0049] The average first RTD value may be calculated from the individual first RTD values ​​of the first aerosol-generating article. Similarly, the average second RTD value may be calculated from the individual second RTD values ​​of the second aerosol-generating article. The average first RTD value may be determined specifically for a predetermined first number of first consecutive rods. The average second RTD value may be determined for a predetermined second number of second consecutive rods.

[0050] The first continuous rod may be cut to provide a single first aerosol-generating article. A first single air injection value for the single first aerosol-generating article may be determined. Similarly, the second continuous rod may be cut to provide a single second aerosol-generating article. A second single air injection value for the single second aerosol-generating article may be determined. The first single air injection value and the second single air injection value may be determined in a similar manner as the air injection value for the first aerosol-generating article described above.

[0051] The first air injection value of a first continuous rod containing two single first aerosol-generating articles may be different from the first single air injection value of one single first aerosol-generating article. Furthermore, the difference between the air injection value of a continuous rod containing two single aerosol-generating articles and the single air injection value of each of the individual aerosol-generating articles created from the rod by cutting may also depend on the RTD value of each continuous rod. For example, a first air injection value of about 44 millimeters H 2 O~59mm H 2 A continuous rod having a filter section with a low pull resistance range of 0 and an air injection value of 70 percent would result in an air injection value of each single aerosol-generating article of 35 percent. 2 O ~ 71mm H 2 A continuous rod having a range of resistance to drawing values ​​of 100 mm and a filter section having an air injection value of 80 percent will result in a single aerosol-generating article having an air injection value of 50 percent after cutting. 2 O~86mm H 2 A continuous rod having filter sections with pull resistance in the range of values ​​of O results, after cutting, in a single aerosol-generating article having an air injection value of 59 percent.

[0052] There may be a correlation between the air injection value of the continuous rod and each of the single air injection values ​​of the single aerosol-generating articles produced by cutting the continuous rod. The correlation between the air injection value of the continuous rod and each of the single rods may depend on the respective RTD values ​​measured for the continuous rod. Thus, measuring the RTD of the continuous rod before production of the ventilation zone in the rod may make it possible to determine which air injection value of the continuous rod is required to result in the desired air injection value in the single aerosol-generating article after cutting. This allows the reference value to be adjusted and set according to the measured RTD of the continuous rod. This allows the reference value of the air injection value of the continuous rod to be set so that a single aerosol-generating article having the desired air injection value can ultimately be produced. This desired air injection value for the single aerosol-generating article after cutting the continuous rod may be 50 percent. When the first and second continuous rods are produced as the first and second aerosol-generating articles, the reference value may be the target air injection value of the continuous rod. This target air injection value of the continuous rod may be set in this manner for the individual aerosol-generating articles having the desired air injection value after cutting the continuous rod. This desired air injection value for a particular aerosol-generating article may be 50 percent.

[0053] The method for producing a ventilation zone in an aerosol-generating article may also comprise setting a reference value in method step D) depending on the RTD value measured for the first aerosol-generating article in method step A2). Depending on whether a high, medium or low pull-out resistance value is measured, a reference value, in particular a reference air injection value, more particularly a reference air injection value for a continuous rod containing two aerosol-generating articles, may be set. Since the air injection value of the continuous rod can be assigned to the air injection value of a single aerosol-generating article after cutting the rod, the desired single air injection value can be obtained by setting the reference air injection value of the continuous rod depending on the RTD value measured for the rod.

[0054] During method step A), a first aerosol-generating article may be provided, the first aerosol-generating article comprising a first hollow tube section and a first substrate section. Preferably, the first aerosol-generating article may further comprise a first filter section. The first hollow tube section may be located downstream of the first substrate section within the first aerosol-generating article.

[0055] The second aerosol-generating article may also comprise a second hollow tube section and a second substrate section. Preferably, the second aerosol-generating article may further comprise a second filter section. The second hollow tube section may be located downstream of the second substrate section within the second aerosol-generating article.

[0056] In particular, the second aerosol-generating article may be structured in the same manner as the first aerosol-generating article. The second aerosol-generating article may contain the same elements as the first aerosol-generating article.

[0057] The first continuous rod may contain two identical first aerosol-generating articles connected to each other. Similarly, the second continuous rod may contain two identical second aerosol-generating articles connected to each other. In the following, the design of the first and second aerosol-generating articles is described in more detail. Thus, any reference to "aerosol-generating article" in general relates to both the first and second aerosol-generating articles. The first and second continuous rods may be formed from the respective first and second aerosol-generating articles, for example by connecting two first aerosol-generating articles.

[0058] As used herein, the terms "upstream" and "downstream" are used to describe the relative location of an aerosol-generating article or a section of an aerosol-generating device used with the aerosol-generating article with respect to the direction in which the aerosol is transported through the aerosol-generating article during use. The aerosol-generating article according to the present invention comprises a proximal end through which the aerosol exits the aerosol-generating article during use. The proximal end of the aerosol-generating device may also be referred to as the mouth end or downstream end. During use, a user inhales the downstream end or mouth end of the aerosol-generating article to inhale the aerosol generated by the aerosol-generating system. The aerosol-generating system comprises an upstream end opposite the downstream end or mouth end. The mouth end is downstream of the distal end. The distal end of the aerosol-generating device or the aerosol-generating article may also be referred to as the upstream end. Components or portions of components of the aerosol-generating article or the aerosol-generating device may be described as being upstream or downstream of each other based on their relative location with respect to the direction of the aerosol being transported through the aerosol-generating article or the aerosol-generating device during use of the aerosol-generating article or the aerosol-generating device.

[0059] The filter section may be a cellulose acetate filter plug, in one embodiment the filter section may be approximately 7 mm long, but may be from approximately 5 mm to approximately 10 mm long.

[0060] The hollow tube section may comprise one or both of a support section and an aerosol cooling section.

[0061] The substrate section may include an aerosol-forming substrate.

[0062] The aerosol-forming substrate may have a length of approximately 10 mm. Alternatively, the aerosol-forming substrate may have a length of approximately 12 mm. Further, the diameter of the aerosol-forming substrate may be between approximately 5 mm and approximately 12 mm.

[0063] By way of example, the hollow tube section may further comprise a support element positioned immediately downstream of the aerosol-forming substrate, and the aerosol cooling element may be located between the support element and the downstream end (or mouth end) of the aerosol-generating article. More particularly, the aerosol cooling element may be positioned immediately downstream of the support element. In some preferred embodiments, the aerosol cooling element may abut the support element.

[0064] The hollow tube section of the aerosol-generating article according to the invention preferably comprises an intermediate hollow section including a support element arranged in alignment with and downstream of the rod of the aerosol-forming substrate, in particular the support element may be located immediately downstream of the rod of the aerosol-forming substrate or adjacent to the rod of the aerosol-forming substrate.

[0065] The support element may be formed from any suitable material or combination of materials. For example, the support element may be formed from one or more materials selected from the group consisting of cellulose acetate, cardboard, crimped paper (such as crimped heat-resistant paper or crimped parchment paper), and polymeric materials (such as low-density polyethylene (LDPE)). In a preferred embodiment, the support element is formed from cellulose acetate. Other suitable materials include polyhydroxyalkanoate (PHA) fibers.

[0066] The support element may comprise a hollow tubular element, hi a preferred embodiment the support element comprises a hollow cellulose acetate tube.

[0067] The support element is disposed substantially in alignment with the rod, meaning that the length dimension of the support element is disposed approximately parallel to the longitudinal direction of the rod and article, for example within ±10 degrees of parallel to the longitudinal direction of the rod. In a preferred embodiment, the support element extends along the longitudinal axis of the rod.

[0068] The support element preferably has an outer diameter approximately equal to the outer diameter of the rod of the aerosol-forming substrate and the outer diameter of the aerosol-generating article.

[0069] The support element may have an outer diameter of 5 millimeters to 12 millimeters, such as an outer diameter of 5 millimeters to 10 millimeters, or an outer diameter of 6 millimeters to 8 millimeters. In a preferred embodiment, the support element has an outer diameter of 7.2 millimeters ±10 percent. The support element may have a length of 5 millimeters to 15 millimeters. In a preferred embodiment, the support element has a length of 8 millimeters.

[0070] The peripheral wall of the support element may have a thickness of at least 1 millimeter, preferably at least about 1.5 millimeters, and more preferably at least about 2 millimeters.

[0071] The support element may have a length of from about 5 millimeters to about 15 millimeters.

[0072] Preferably, the support element has a length of at least about 6 millimeters, and more preferably, has a length of at least about 7 millimeters.

[0073] In a preferred embodiment, the support element has a length of less than about 12 millimeters, more preferably less than about 10 millimeters.

[0074] In some embodiments, the support element has a length of about 5 millimeters to about 15 millimeters, preferably about 6 millimeters to about 15 millimeters, and more preferably about 7 millimeters to about 15 millimeters. In other embodiments, the support element has a length of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 12 millimeters, and more preferably about 7 millimeters to about 12 millimeters. In further embodiments, the support element has a length of about 5 millimeters to about 10 millimeters, preferably about 6 millimeters to about 10 millimeters, and more preferably about 7 millimeters to about 10 millimeters.

[0075] In a preferred embodiment, the support element has a length of about 8 millimeters.

[0076] The ratio between the length of the support element and the length of the rod of the aerosol-forming substrate may be from about 0.25 to about 1.

[0077] Preferably, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is at least about 0.3, more preferably at least about 0.4, even more preferably at least about 0.5. In a preferred embodiment, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is less than about 0.9, more preferably less than about 0.8, even more preferably less than about 0.7.

[0078] In some embodiments, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is about 0.3 to about 0.9, preferably about 0.4 to about 0.9, more preferably about 0.5 to about 0.9. In other embodiments, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is about 0.3 to about 0.8, preferably about 0.4 to about 0.8, more preferably about 0.5 to about 0.8. In further embodiments, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is about 0.3 to about 0.7, preferably about 0.4 to about 0.7, more preferably about 0.5 to about 0.7.

[0079] In a particularly preferred embodiment, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is about 0.66.

[0080] The ratio between the length of the support element and the overall length of the aerosol-generating article substrate may be from about 0.125 to about 0.375.

[0081] Preferably, the ratio between the length of the support element and the overall length of the aerosol-generating article substrate is at least about 0.13, more preferably at least about 0.14, and even more preferably at least about 0.15. The ratio between the length of the support element and the overall length of the aerosol-generating article substrate is preferably less than about 0.3, more preferably less than about 0.25, and even more preferably less than about 0.20.

[0082] In some embodiments, the ratio between the length of the support element and the total length of the aerosol-generating article substrate is preferably about 0.13 to about 0.3, more preferably about 0.14 to about 0.3, even more preferably about 0.15 to about 0.3. In other embodiments, the ratio between the length of the support element and the total length of the aerosol-generating article substrate is preferably about 0.13 to about 0.25, more preferably about 0.14 to about 0.25, even more preferably about 0.15 to about 0.25. In further embodiments, the ratio between the length of the support element and the total length of the aerosol-generating article substrate is preferably about 0.13 to about 0.2, more preferably about 0.14 to about 0.2, even more preferably about 0.15 to about 0.2.

[0083] In a particularly preferred embodiment, the ratio between the length of the support element and the overall length of the aerosol-generating article substrate is about 0.18.

[0084] In an aerosol-generating article according to the invention, the support element preferably has an average radial hardness of at least about 80 percent, more preferably at least about 85 percent, and even more preferably at least about 90 percent. Thus, the support element is capable of providing the aerosol-generating article with the desired level of hardness.

[0085] If desired, the radial hardness of the support element of an aerosol-generating article according to the invention may be further increased by surrounding the support element with a stiff plug wrap, such as a plug wrap having a basis weight of at least about 80 grams per square meter (gsm), or at least about 100 gsm, or at least about 110 gsm.

[0086] During the insertion of the aerosol-generating article according to the invention into an aerosol-generating device for heating the aerosol-forming substrate, the user may need to apply some force to overcome the resistance to the insertion of the aerosol-forming substrate of the aerosol-generating article. This may damage one or both of the aerosol-generating article and the aerosol-generating device. In addition, the application of force during the insertion of the aerosol-generating article into the aerosol-generating device may cause the aerosol-forming substrate in the aerosol-generating article to be displaced. This may result in the heating element of the aerosol-generating device not being properly aligned with the susceptor provided in the aerosol-forming substrate, which may lead to uneven and inefficient heating of the aerosol-forming substrate of the aerosol-generating article. The support element is advantageously configured to resist downstream movement of the aerosol-forming substrate during the insertion of the article into the aerosol-generating device.

[0087] In an aerosol-generating article according to the invention, the overall RTD of the article depends essentially on the RTD of the substrate section and, optionally, the filter section, since the hollow tubular section of the aerosol-cooling element and the hollow tubular section of the support element are substantially empty and therefore only make a substantially small contribution to the overall RTD of the aerosol-generating article.

[0088] The overall RTD value of a single aerosol-generating article having a vent zone produced according to the method of the present invention and after cutting of the continuous rod is approximately 30 millimeters H 2 O ~ approx. 70 mmH 2 0, preferably approximately 40 mm H 2 O ~ Approximately 60 mmH 2 It may be O.

[0089] The aerosol-forming substrate may include an aerosol former. The aerosol former is any suitable known compound or mixture of compounds that facilitates the formation of a dense, stable aerosol during use and is substantially resistant to thermal decomposition at the operating temperature of the aerosol generating system. Suitable aerosol formers may include, but are not limited to, polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, and the like). The aerosol former may be a polyhydric alcohol or a mixture thereof (such as triethylene glycol, 1,3-butanediol, and glycerin). The aerosol former may be propylene glycol. The aerosol former may include both glycerin and propylene glycol. The aerosol former may include only glycerin.

[0090] The aerosol former may be present in an amount of 20 weight percent to 58 weight percent, preferably 25 weight percent to 45 weight percent, more preferably 30 weight percent to 38 weight percent on a dry weight basis based on the total weight of the aerosol-forming substrate. The term "dry weight basis" refers throughout this application to the calculated weight of the aerosol-forming substrate after removing water via Karl Fischer titration, e.g., heating to a temperature of 110 degrees Celsius at standard conditions of temperature and pressure, and using potentiometry to determine the end point. The end point is detected by a bipotentiometric titration method. A second pair of Pt electrodes is immersed in the anodic solution. A detector circuit maintains a constant current between the two detector electrodes during the titration. Before the equivalence point, the solution is charged to a temperature of I - Contains I 2 At the equivalence point, excess I 2 appears and a sudden voltage drop indicates the end point. Then, I 2The amount of charge required to generate and reach the endpoint can be used to calculate the amount of water in the original sample. The aerosol former content can be measured by gas chromatography coupled with a flame ionization detector.

[0091] In certain preferred embodiments, the aerosol-forming substrate may comprise homogenized plant material, preferably homogenized tobacco material.

[0092] The term "homogenized plant material" as used herein includes any plant material formed by agglomeration of plant particles. For example, a sheet or web of homogenized tobacco material for the aerosol-forming substrate of the present invention may be formed by agglomerating particles of tobacco material obtained by grinding, crushing, or comminuting plant material and, optionally, one or more of tobacco lamina and tobacco stems. The homogenized plant material may be produced by casting, extrusion, a papermaking process, or any other suitable process known in the art.

[0093] The homogenized plant material may be provided in any suitable form. For example, the homogenized plant material may be in the form of one or more sheets. The term "sheet" as used herein with respect to the present invention describes a laminar element having a width and length substantially greater than its thickness.

[0094] The homogenized plant material may be in the form of a plurality of pellets or granules.

[0095] The homogenized plant material may be in the form of multiple strands, strips, or pieces. As used herein, the term "strand" describes an elongated element of material having a length substantially greater than its width and thickness. The term "strand" should be considered to encompass strips, pieces, and any other homogenized plant material having a similar morphology. Strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example, by cutting or shredding, or by other methods, such as extrusion methods.

[0096] The tobacco particles may have a nicotine content of at least about 2.5 weight percent based on dry weight. More preferably, the tobacco particles may have a nicotine content of at least about 3 weight percent based on dry weight, even more preferably at least about 3.2 weight percent, even more preferably at least about 3.5 weight percent, and most preferably at least about 4 weight percent.

[0097] At least one susceptor element may be located within the substrate section. Generally, the susceptor may include or be made of a material capable of generating heat when an alternating magnetic field penetrates it. If the susceptor is conductive, then typically, eddy currents are induced by the alternating magnetic field. If the susceptor is magnetic, then typically, another effect that contributes to heating is commonly referred to as hysteresis loss. Hysteresis loss occurs primarily due to the movement of magnetic domain blocks within the susceptor, as their magnetic orientation aligns with the alternating induced magnetic field. Another effect that contributes to hysteresis loss is when magnetic domains expand or contract within the susceptor. Generally, all these changes that occur within the susceptor at nanoscale or below generate heat within the susceptor, and are therefore referred to as "hysteresis loss". Thus, if the susceptor is both magnetic and conductive, then both hysteresis loss and the generation of eddy currents will contribute to the heating of the susceptor particles. If the susceptor is magnetic but not conductive, hysteresis losses will be the only means by which the susceptor will heat when penetrated by an alternating magnetic field. The alternating magnetic field generated by one or several induction coils heats the susceptor, which then transfers heat to other components of the aerosol-forming substrate. This may facilitate the formation of the aerosol. Heat transfer may be primarily by thermal conduction.

[0098] The susceptor may be ferromagnetic. The ferromagnetic susceptor may comprise or consist of a metal or a metal oxide. The ferromagnetic susceptor may comprise one or more of iron, cobalt, nickel, or oxides thereof. Preferably, the susceptor is Fe 2 O 3 It may comprise or consist of.

[0099] The aerosol-generating article may further comprise a filter plug in a filter section downstream of the ventilation zone. The filter plug has a resistance to withdrawal (RTD) of 5 millimeters H 2 O~80mm H 2 o, preferably 10 mm H 2O~65mm H 2 o, more preferably 15 mm H 2 O~50mm H 2 o, more preferably 20 mm H 2 O~40mm H 2 o, most preferably 30 mm H 2 It may be O.

[0100] During method step B), perforations may be formed in the hollow tube section. A ventilation zone in the hollow tube section may allow ambient air to easily enter the aerosol-generating article during a user's puff. The ventilation zone in the hollow tube section may be located downstream of the substrate section. This may allow the airflow or aerosol originating from the aerosol-forming substrate in the substrate section to mix and cool with the ambient air entering the aerosol-generating article through the perforations. This may improve aerosol generation.

[0101] The ventilation zone formed during method step b) may comprise 5 to 15 perforations, preferably 7 to 14 perforations, more preferably 9 to 13 perforations, more preferably 10 to 12 perforations, most preferably 11 perforations.

[0102] The ventilation zone may comprise 10 to 12 perforations.

[0103] Having a ventilation zone with perforations may allow ambient air to be drawn into the ventilation zone. This ambient air may mix with the air drawn through the substrate section. The substrate section may be heated by the aerosol generating device such that the aerosol-forming substrate is volatilized. The volatilized aerosol-forming substrate may be entrained in the air flowing through the rod of aerosol-forming substrate. This airflow mixes with the ambient air downstream of the substrate section in the ventilation zone. The mixture of the ambient air and the air drawn through the substrate section cools to form an aerosol. Having a relatively small number of perforations, specifically 10-12 perforations, improves the mixing of the ambient air drawn into the ventilation zone through the perforations and the air drawn through the substrate section into the ventilation zone. This improved mixing may result in improved aerosol generation. Without being bound by any theory, it has been found that 10-12 perforations lead to the best mixture of ambient air and air carrying the volatilized aerosol-forming substrate. The reason may be that this relatively small number of perforations requires relatively large perforations to allow a sufficient amount of ambient air to be drawn into the ventilation zone. The relatively large perforations may lead to a relatively strong turbulence between the two air streams and therefore improved mixing of the two air streams. The air stream coming from the perforations may be strong enough to break the main air stream coming from the aerosol-forming substrate, thereby improving the mixing of the air streams.

[0104] The ventilation zone may comprise 11 perforations.

[0105] It has been shown that this number of perforations leads to the best mixture of ambient air and air carrying the volatilized aerosol-forming substrate.

[0106] The perforations may be disposed surrounding the ventilation zone.The perforations may be disposed at least partially surrounding the ventilation zone.

[0107] During method step A), a continuous rod may be provided as aerosol-generating articles. The continuous rod may comprise up to 10 individual aerosol-generating articles, preferably up to 5 individual aerosol-generating articles, more preferably up to 2 individual aerosol-generating articles. Most preferably, the continuous rod may comprise two individual aerosol-generating articles. The individual aerosol-generating articles may be manufactured by cutting the continuous rod into individual aerosol-generating articles. The continuous rod may comprise two individual aerosol-generating articles interconnected, the downstream filter sections of both single aerosol-generating articles being located adjacent to each other within the continuous rod.

[0108] Each aerosol-generating article may comprise an upstream substrate section and at least one hollow tube section located downstream of the substrate section, preferably adjacent the substrate section, and further downstream of the at least one hollow tube section may be a filter section, e.g. a filter plug, such as a cellulose acetate filter plug.

[0109] The aerosol-generating articles produced by the methods of the present invention may be used in an aerosol-generating system, which may comprise an aerosol-generating article as described herein and an aerosol generating device comprising a cavity for receiving the aerosol-generating article.

[0110] Such an aerosol-generating system may be configured to provide an aerosol from an aerosol-forming substrate of the substrate section of the aerosol-generating article described herein.

[0111] The cavity of the aerosol-generating device may have an inner wall with sections that protrude inwardly into the cavity. These protruding sections may contact an aerosol-generating article received in the cavity. These protruding sections may allow for the formation of an airflow path between the inner wall of the cavity and the aerosol-generating article. This may also allow for the formation of an airflow path that leads to the above-mentioned ventilation zone of the aerosol-generating article.

[0112] The aerosol generating device may include a heating element, specifically an induction heating element such as an induction coil. With induction heating of the aerosol-forming substrate of the aerosol-generating article received in the aerosol generating device, the susceptor may be heated by the alternating magnetic field of the induction heating element. This may also heat the aerosol-forming substrate. For induction heating, the heating element preferably comprises an induction coil. To generate the alternating magnetic field, an alternating current may be supplied to the induction coil. The alternating current may have a high frequency. As used herein, the term "high frequency oscillating current" refers to an oscillating current having a frequency of 500 kilohertz to 30 megahertz. The high frequency oscillating current may have a frequency of about 1 megahertz to about 30 megahertz, preferably about 1 megahertz to about 10 megahertz, and more preferably about 5 megahertz to about 8 megahertz.

[0113] The heating element may be configured to heat the aerosol-generating article to a temperature in the range of 220° C. to 400° C., preferably 250° C. to 290° C. The heating element may be configured to heat the aerosol-generating article, in particular the aerosol-forming substrate, to a temperature below the combustion temperature of the aerosol-forming substrate. This may enable the use of aerosols generated from "heat-non-combustion" aerosol-generating articles.

[0114] The heating element may be configured as a resistive heating element. The heating element may be configured as a resistive heating coil at least partially surrounding the cavity for receiving the aerosol-generating article.

[0115] The heating element may be located adjacent to the cavity for receiving the aerosol-generating article. The heating element may be located at least partially around the cavity to heat the aerosol-generating article received in the cavity. The heating element may surround the periphery of the cavity for receiving the aerosol-generating article. This may allow for reliable and uniform heating of the substrate section of the aerosol-generating article. EXAMPLES

[0116] The following provides a non-exhaustive list of non-limiting examples, any one or more of the features of which may be combined with any one or more features of the other examples, embodiments, or aspects described herein.

[0117] Example A 1. A method for producing a first ventilation zone in a first aerosol-generating article and a second ventilation zone in a second aerosol-generating article, comprising: A) providing a first aerosol-generating article; B) a method step of forming a first perforation in a first aerosol-generating article, thereby creating a first ventilation zone; C) a method step of determining a first air injection value for a first aerosol-generating article, the method step being characterized in that the air injection value is determined according to the formula (P in -P out )·100% / P in where P is the in is the air pressure applied to the first end surface of the article, and P out is the air pressure sensed at the second end surface of the article; D) a method step of comparing the first air injection value with a reference value; and E) providing a second aerosol-generating article and forming a second perforation in the second aerosol-generating article, thereby creating a second ventilation zone, wherein the size of the second perforation is adjusted based on a comparison of the determined first air injection value with a reference value. Example B. The manufacturing method described in example A, wherein during method step C), an air blast is applied to the first aerosol-generating article and a pressure differential is measured between both opposing first and second end faces of the first aerosol-generating article. Example C The method of any of Examples A-B, wherein a first continuous rod is provided as a first aerosol-generating article and a second continuous rod is provided as a second aerosol-generating article, and the first continuous rod and the second continuous rod comprise at least two aerosol-generating articles, preferably the first continuous rod and the second continuous rod comprise two aerosol-generating articles. Example D. A method according to any of Examples A to C for producing first ventilation zones within a predetermined first number of first aerosol-generating articles, wherein during method steps A) and B), a first perforation is formed in each of the first aerosol-generating articles of the first predetermined number of first aerosol-generating articles, and during method step C), individual first air injection values ​​of the first aerosol-generating articles are determined and an average first air injection value is calculated. Example E The method of embodiment D for further producing a second ventilation zone within a predetermined second number of second aerosol-generating articles, wherein during method step E), a predetermined second number of second aerosol-generating articles is provided and second perforations are formed in each of the second aerosol-generating articles of the predetermined second number of first aerosol-generating articles based on a comparison between the determined average first air injection value and a reference value. Example F. The method of any one of Examples A to E, wherein the reference value is a target air injection value for the first aerosol-generating article and the second aerosol-generating article. Example G A method for producing a product according to any of Examples A to F, wherein in method step A2) prior to method step B), a first resistance to withdrawal RTD value of the first aerosol-generating article is measured, more preferably the RTD value is measured by applying a constant air flow to a 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. Example H. The method of example G, further dependent on example D, wherein an individual first RTD value is determined for each first aerosol-generating article of the predetermined first number of first aerosol-generating articles. Example I The manufacturing method described in Example H, wherein the individual first air injection values ​​of the first aerosol-generating articles determined in step C) are corrected based on the first individual resistance to draw (RTD) values, thereby providing corrected individual first air injection values, and an average corrected first air injection value is calculated based on the corrected individual first air injection values. Example J. The manufacturing method described in Example I, wherein in step E), the average corrected first air injection value is compared to a reference value, and in step E), the size of the second perforations is adjusted based on the comparison of the average corrected first air injection value to the reference value. Example K A method for producing a product according to any of Examples A to J, wherein in method step E) the second air injection value of the second aerosol-generating article is determined, preferably in accordance with claim 5, wherein individual second air injection values ​​of the second aerosol-generating articles are determined and an average second air injection value is calculated. Example L. A manufacturing method as described in any of Examples A to K, wherein the second withdrawal resistance RTD values ​​of the second aerosol-generating articles are more preferably measured in accordance with claim 5, and individual second RTD values ​​are determined for each of the second aerosol-generating articles of a predetermined second number of first aerosol-generating articles. Example M. The method of example L, further described in example H, wherein the average first RTD value is calculated from the individual first RTD values ​​of the first aerosol-generating articles and the average second RTD value is calculated from the individual second RTD values ​​of the second aerosol-generating articles of a predetermined second number of the first aerosol-generating articles. Example N. The method of embodiment M, wherein the reference value is set in method step D) in response to the RTD value measured for the first aerosol-generating article in method step A2). Example O. A method for producing aerosol-generating articles as described in Examples D, E and H-O, wherein the predetermined first number of aerosol-generating articles is the same as the predetermined second number of aerosol-generating articles, and preferably the predetermined first and second numbers of aerosol-generating articles are at least 50, preferably at least 100, more preferably at least 1000 aerosol-generating articles. Example P. A method for producing an aerosol-generating article as described in Example I, wherein during method step D), a delta value is calculated, which is the difference between the average corrected first air injection value and a reference value, and in method step E), the size of the second perforation is adjusted based on the delta value. Example Q. The method of manufacturing according to embodiment P, wherein in step E) the size of the second perforations is one of reduced or increased compared to the size of the first perforations. Example R. The method of any of embodiments A-Q, wherein during method step C), the air injection value within the aerosol-generating article is determined at a constant air pressure at the first end face. Example S. The manufacturing method according to any of the embodiments A to R, wherein during the method step B) a slit or an oval is formed as the first perforation, the first perforation having a width and a length, and during the method step E) the length of the second perforation is adjusted. Example T The manufacturing method according to any of the embodiments A to S, wherein during the method steps B) and E), a laser device is used to form the first and second perforations and to increase the size of the first and second perforations. Example U. The method of any of Examples A-T, wherein during method step A), a first aerosol-generating article is provided, the first aerosol-generating article comprising a first hollow tube section and a first substrate section, preferably the first aerosol-generating article further comprising a first filter section. Example V The method of claim U, wherein during method step B), a first perforation is formed in the first hollow tube section.

[0118] Features described with respect to one embodiment may be equally applied to other embodiments of the invention.

[0119] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which:

[0120] In the following, identical elements are designated by the same reference numerals throughout the figures.

[0121] FIG. 1 shows a flow diagram of one embodiment of the present invention. In a method step A), a first continuous rod, in particular comprising two individual first aerosol-generating articles without ventilation zones, is provided, as indicated by the box entitled "Assembled Stick". In a second method step B), a first perforation is generated in the aerosol-generating article, in particular in its first hollow tube section, as indicated by the box entitled "Perforation". This can be done, for example, by using a laser. In a third step C), a first air injection value of the first continuous rod, comprising two individual first aerosol-generating articles, is determined, as indicated in the box entitled "Air injection measurement (on double stick)". In a next step D), the first injection value is compared with a reference value (box entitled "Air injection in target"). If the measured first air injection value is below or above the reference value, the laser perforation parameters are adapted. The size of the second perforations in the second ventilation zone of the subsequently treated second aerosol-generating article, in particular their length, is increased or decreased in a subsequent method step E) in order to obtain a second aerosol-generating article having a new second air injection value that is closer to the reference value, as shown by the box entitled "Perforation parameters are adapted (slit length)".

[0122] Figure 2 shows a flow diagram of another embodiment of the method of the present 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 Figure 1. Furthermore, this embodiment of the present invention includes a method step A2) prior to method step B), in which the individual first RTD values ​​of a given first plurality of first aerosol-generating articles are measured and an average is determined (box entitled "RTD calculation"). Then, both method steps D) include applying an RTD correction factor based on the average of the RTD values ​​determined in method step A2 to the air injection value determined in method step C, and comparing this RTD correction value with a reference value (boxes indicating "RTD correction factor applied to measurement" and box entitled "Air injection in target").

[0123] FIG. 3 shows 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 can typically be used by the method of the present invention to produce two first ventilation zones within the double stick. The 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 a hollow tube section 14, which consists of a hollow support element 16 and an aerosol cooling element 18. This hollow tube section 14 is adjacent to a substrate section 22 in the individual aerosol-generating articles 10, each substrate section 22 housing a susceptor 24. This substrate section 22 is adjacent to a filter element 26 in each aerosol-generating article. In the continuous rod, two first ventilation zones 12 are formed within the hollow tube section 14 of each individual first aerosol-generating article during method step B) of the present invention. The air injection value of such a first continuous rod 11 can be measured by applying a certain pressure to a first end face 11A of the rod and determining the air pressure passed through the rod at a 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 to the first end face 11A, as air passes through the perforations in the ventilation zones 12 reducing the air pressure.

[0124] The length of such a double stick may be 90 mm. As a result, the length of the individual aerosol-generating articles after cutting of the double stick may be 45 mm. The diameter of the double stick may be 7.25 mm.

[0125] Figure 4 shows a schematic diagram of one individual perforation 12A of the larger ventilation zone 12 shown in Figure 3. Perforation 12A has an elliptical shape with width 13 and length 15. During method step E) of the method of the invention, it is preferred that only length 15 is increased in order to make the measured air injection values ​​better match the reference values.

[0126] FIG. 5 shows a graph showing compensation factors for correcting the air injection values ​​determined during the method for producing aeration zones based on RTD values ​​to obtain the respective air injection values ​​under laboratory conditions at constant air flow. The graph was obtained by fitting a curve to each individual value shown by a black dot. The graph shows that for an RTD value of the double stick of about 60 mmWg, the compensation factor is about -5 percent. For an RTD value of the double stick of about 100 mmWg, the compensation factor is 0. For a high RTD value of the double stick of about 140 mmWg, the compensation factor is about 2 percent.

[0127] 6 shows a graph illustrating the correlation between the RTD value of the double stick and the respective air injection value of the double stick, which should be set as a reference value to obtain an individual aerosol-generating article having a desired air injection value of 50 percent after cutting the double stick. The graph shows that the correlation between the air injection of the double stick and the resulting air injection of the individual aerosol-generating article after cutting the double stick depends on the pull-out resistance value of the double stick.

Claims

1. 1. A method for producing a first ventilation zone in a first aerosol-generating article and a second ventilation zone in a second aerosol-generating article, comprising: A) providing a first aerosol-generating article; B) forming a first perforation in said first aerosol-generating article, thereby creating a first ventilation zone; C) determining a first air injection value for said first aerosol-generating article, said air injection value being calculated according to the formula (P in -P out ) 100% / P in where P in is an air pressure of 5 mbar to 50 mbar applied to the first end surface of the article, and P out is the air pressure sensed at the second end surface of the article; D) a method step of comparing said first inflation value with a reference value; E) providing a second aerosol-generating article and forming second perforations in the second aerosol-generating article, thereby creating the second ventilation zone, wherein the size of the second perforations is adjusted based on a comparison of the determined first air injection value with the reference value, and during method step C), an air blast is applied as air pressure to the first aerosol-generating article for a period of 25 milliseconds to 60 milliseconds, and the pressure differential is measured between both the opposing first and second end faces of the first aerosol-generating article as shown by the above formula; A method comprising:

2. 2. The method of claim 1, wherein a first continuous rod is provided as a first aerosol-generating article and a second continuous rod is provided as a second aerosol-generating article, and the first continuous rod and the second continuous rod comprise at least two aerosol-generating articles.

3. 2. A method for producing first ventilation zones within a predetermined first number of first aerosol-generating articles, wherein during method steps A) and B), a predetermined first number of first aerosol-generating articles are provided, and the first perforations are formed in each of the first aerosol-generating articles of the predetermined first number of first aerosol-generating articles, and during method step C), individual first air injection values ​​of the first aerosol-generating articles are determined and an average first air injection value thereof is calculated.

4. The method of any one of claims 1 to 3, wherein the reference value is a target air injection value for the first aerosol-generating article and the second aerosol-generating article.

5. 4. The method according to claim 1, wherein in method step A2) prior to method step B), a first withdrawal resistance RTD value of the first aerosol-generating article is measured in accordance with ISO 6565-2015.

6. 6. The method of claim 5, wherein an individual first RTD value is determined for each of the first aerosol-generating articles of the predetermined first number of first aerosol-generating articles.

7. 7. The manufacturing method of claim 6, wherein the individual first air injection values ​​of the first aerosol-generating articles determined in step C) are corrected based on the first individual resistance to draw (RTD) values, thereby providing corrected individual first air injection values, and an average corrected first air injection value is calculated based on the corrected individual first air injection values.

8. 8. The manufacturing method of claim 7, wherein in step E), the average corrected first air injection value is compared to the reference value, and in step E), the size of the second perforations is adjusted based on the comparison of the average corrected first air injection value with the reference value.

9. 9. The method of claim 8, wherein an average first RTD value is calculated from the individual first RTD values ​​of the first aerosol-generating articles, and an average second RTD value is calculated from the individual second RTD values ​​of the second aerosol-generating articles of the predetermined second number of first aerosol-generating articles.

10. 10. The method of claim 9, wherein the reference value is set in method step D) in response to the RTD value measured for the first aerosol-generating article in method step A2).

11. 4. The method for manufacturing aerosol-generating articles according to claim 3, wherein the predetermined first number of aerosol-generating articles is the same as the predetermined second number of aerosol-generating articles.

12. 4. The method according to claim 1, wherein in step E), the size of the second perforations is one of reduced and increased compared to the size of the first perforations.

13. 4. The method according to claim 1, wherein during method step B) slits or ellipses are formed as first perforations, said first perforations having a width and a length, and during method step E) the length of the second perforations is adjusted.

14. 4. The method of claim 1, wherein during method step A), a first aerosol-generating article is provided, said first aerosol-generating article comprising a first hollow tube section and a first substrate section.

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