WO2015039851A2

WO2015039851A2 - Inspection of rod shaped articles of the tobacco industry

Info

Publication number: WO2015039851A2
Application number: PCT/EP2014/068301
Authority: WO
Inventors: Julian White; Martin Horrod; Andrew Jonathan Bray; Gary Fallon
Original assignee: British American Tobacco Investments Ltd IFI; British American Tobacco Co Ltd
Current assignee: British American Tobacco Investments Ltd IFI
Priority date: 2013-09-20
Filing date: 2014-08-28
Publication date: 2015-03-26
Anticipated expiration: 2016-03-20
Also published as: WO2015039851A3; GB201316691D0; WO2015039851A8

Abstract

An apparatus for inspecting a rod shaped article of the tobacco industry, including an optical output configured to output a beam of electromagnetic radiation, a first receiver and a second receiver. The first receiver is for receiving radiation which has been output by the optical output and transmitted through the rod shaped article. Moreover, the optical output and the first receiver face each other. The second receiver is for receiving radiation which has been output by the optical output and redirected within the rod shaped article. Furthermore, the first and second receivers are configured to lo generate complementary signals to be analysed to provide information relating to the interior of the rod shaped article.

Description

Inspection of Rod Shaped Articles of the Tobacco Industry Technical Field

The specification discloses apparatus for inspecting one or more rod shaped articles of the tobacco industry using electromagnetic radiation. Background

Various methods exist for using electromagnetic radiation to inspect articles of the tobacco industry.

Summary

In one embodiment there is provided an apparatus for inspecting a rod shaped article of the tobacco industry, comprising an optical output configured to output a beam of electromagnetic radiation; a first receiver for receiving radiation which has been output by the optical output and transmitted through the rod shaped article, wherein the optical output and the first receiver face each other; a second receiver for receiving radiation which has been output by the optical output and redirected within the rod shaped article; and wherein the first and second receivers are configured to generate complementary signals to be analysed to provide information relating to the interior of the rod shaped article.

The apparatus may comprise a rod input configured to receive the rod shaped article and arranged so that the rod can be conveyed from the rod input through the beam of output radiation in the direction of a longitudinal axis of the article, and the first and second receivers may be configured to generate said complementary signals as the rod shaped article is conveyed through the beam.

The apparatus of may be configured such that the output beam of radiation is transverse to the direction of movement of the article as it is conveyed. Moreover, the apparatus may be configured such that the radiation which has been output by the optical output and redirected within the rod shaped article is redirected in a direction transverse to the direction of movement of the article as it is conveyed.

The apparatus may further comprise a processor configured to analyse the

complementary signals to provide information relating to the interior of the rod, wherein analysing comprises assessing one or more variations in the signals in order to determine an internal variation status. The internal variation status may relate to one or more internal features of the rod, for example a density variation, a presence of an object within the article, a presence of a cavity within the article, a presence of water or another substance within the article, or a structural variation.

Furthermore, the apparatus may comprise a second optical output configured to output a beam of electromagnetic radiation; a third receiver for receiving radiation which has been output by the second optical output and transmitted through the rod shaped article, wherein the second optical output and the third receiver face each other; a fourth receiver for receiving radiation which has been output by the second optical output and redirected within the rod shaped article; and wherein the third and fourth receivers are configured to generate complementary signals to be analysed to provide information relating to the interior of the article. Moreover, the signals of the third and fourth receivers may also be complementary to the signals of the first and second receivers.

In another embodiment there is provided an apparatus for inspecting a rod shaped article of the tobacco industry, the article including one or more non-homogeneities, comprising a first inspection unit configured to inspect in a first direction; a second inspection unit configured to inspect in a second direction different to the first direction; and a processor; wherein the first inspection unit comprises a first optical output and a first receiver, and the second inspection unit comprises a second optical output and a second receiver; the first optical output is configured to output a first beam of electromagnetic radiation in the first direction and the second optical output is configured to output a second beam of electromagnetic radiation in the second direction; each of the first receiver and the second receiver is configured to generate a signal comprising information on the intensity of radiation received; the apparatus is configured to receive a rod shaped article and is arranged such that the received rod shaped article can be conveyed through the first beam and the second beam in the direction of a longitudinal axis of the rod shaped article; and the processor is configured to process the signals to determine information relating to offset of one or more non-homogeneities relative to the longitudinal axis of the received rod shaped article, based on the relative intensity of the radiation which is received at the first and second receivers. The determined information relating to offset of the one or more non-homogeneities may comprise information indicating that at least one of said non-homogeneities is in one of a plurality of regions of a cross sectional area of the rod shaped article.

The first receiver maybe configured to generate said signal as the rod shaped article is conveyed through the first beam, and the second receiver may be configured to generate said signal as the rod shaped article is conveyed through the second beam.

Furthermore, the apparatus may be configured such that the first beam is transverse to the direction of movement of the article as it is conveyed. The apparatus may additionally or alternatively be configured such that the second beam is transverse to the direction of movement of the article as it is conveyed.

The apparatus may be configured such that the radiation output in the first direction substantially intersects the radiation output in the second direction. Moreover, the first optical output may be configured to output radiation at a first wavelength and the second optical output maybe configured to output radiation at a second wavelength, wherein the first and second wavelengths are substantially different; and the apparatus may further comprise a first optical filter and a second optical filter, wherein the first optical filter is configured to prevent radiation at the second wavelength from reaching the first receiver, and the second optical filter is configured to prevent radiation at the first wavelength from reaching the second receiver. The apparatus may comprise a third inspection unit configured to inspect in a third direction; wherein the third inspection unit comprises a third optical output and a third receiver; the third optical output is configured to output a third beam of

electromagnetic radiation in the third direction; the third receiver is configured to generate a signal comprising information on the intensity of radiation received; the apparatus is arranged such that the received rod shaped article can be conveyed through the third beam in the direction of a longitudinal axis of the rod shaped article; and the processor is configured to process the signals from the first, second and third receivers to determine information relating to offset of one or more non-homogeneities relative to the longitudinal axis of the received rod shaped article, based on the relative intensity of the radiation which is received at the first, second and third receivers.

In another embodiment there is provided a method of determining information relating to offset of one or more non-homogeneities of a rod shaped article relative to a longitudinal axis of the rod shaped article, the method comprising receiving a first signal comprising information on the intensity of radiation passing through the rod shaped article in a first direction; receiving a second signal comprising information on the intensity of radiation passing through the rod shaped article in a second direction; processing the signals to determine information relating to offset of the one or more non-homogeneities relative to the longitudinal axis of the received rod shaped article, based on the relative intensity of the radiation which is received at the first and second receivers.

In another embodiment there is provided tobacco industiy apparatus for

manufacturing a rod shaped article, comprising an apparatus for inspecting the rod shaped article as claimed in any preceding claim. For example, the tobacco industry apparatus may comprise a filter rod maker, a tobacco rod maker or a cigarette assembler.

As used herein, the term "rod shaped articles of the tobacco industry" includes solid rod or tubular articles of the tobacco industry, such as filter rods or tobacco rods.

Furthermore, the term includes rod or tube shaped assembled smokeable products such as cigarettes, cigars and cigarillos, whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes, and also heat-not-burn products (i.e. products in which flavour is generated from a smoking material by the application of heat without causing combustion of the material). Any reference to a filter rod, tobacco rod or an assembled smokable product such as a cigarette can be replaced by a reference to a rod shaped article of the tobacco industry.

Brief Description of the Drawings

Embodiments will now be described, byway of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic sectional view of an apparatus for inspecting a rod shaped article of the tobacco industry;

FIG. 2 is a schematic view of a machine for inspecting filter rods comprising the inspection apparatus 1 of FIG. 1; FIG. 3 is a graph illustrating complementary signals generated by the inspection apparatus of FIG. 1; FIG. 4 is a schematic sectional view of the inspection apparatus of FIG. l comprising a second inspection unit;

FIG. 5 is a schematic side view of the apparatus of FIG. 4;

FIG. 6 is a schematic sectional view of a inspection apparatus for inspecting a rod shaped article of the tobacco industry;

FIG. 7 is a side view of the apparatus of FIG. 6;

FIG. 8 is a cross-section view of the filter rod at a capsule and illustrates cross-sectional regions of the filter rod;

FIG. 9 is a schematic view of a machine 140 for inspecting filter rods comprising the inspection apparatus of FIG. 6; and

FIG. 10 is a schematic sectional view of the inspection apparatus configured such that each of the first, second, third and fourth inspection units share a common inspection block.

Detailed Description Referring to FIG. 1, a schematic sectional view of a inspection apparatus 1 for inspecting a rod shaped article of the tobacco industry is shown.

The inspection apparatus 1 is configured to facilitate the determining of information relating to internal features of a received rod shaped article. In more detail, the inspection apparatus 1 is configured to pass a beam of radiation through the article. Moreover, the inspection apparatus 1 is configured to generate complementary electrical signals based on radiation which passes through the article and radiation which is redirected by the interior of the article. Furthermore, the inspection apparatus 1 is configured to analyse the complementary signals to determine the information relating to internal features of a received rod shaped article. The inspection apparatus 1 comprises an inspection unit 2 and a processing device 3. The inspection unit 2 comprises an optical source 4, first receiver 5, second receiver 6 and an inspection block 7.

A rod shaped article 8 is also shown as having been received by the inspection unit 2 and as being inspected. The rod shaped article 8 is a cellulose acetate filter rod 8 comprising one or more capsules 9 embedded therein. The capsule 9 may for example be substantially spherical, formed from gelatin and contain a flavourant, for example menthol, spearmint, orange essence, mint, liquorice, eucalyptus, one or more of a variety of fruit flavours or any mixture of flavourants. Moreover, the capsule may contain a humectant such as water or glycerol. By applying pressure to the outside of the filter rod 8 the capsule 9 can be ruptured, thereby releasing the flavourant.

Released flavourant can act to flavour smoke drawn through the filter rod 8 when it is incorporated in a smoking article such as a cigarette.

The optical source 4 comprises a radiation generator 10 and an optical output 11.

The radiation generator 10 is configured to generate radiation and to provide this to the optical output 11. The optical output 11 is configured to receive the generated radiation from the radiation generator 10 and to output a beam 12 of the generated radiation.

For example, the radiation generator 10 maybe an infrared laser diode configured to provide the generated infrared light to the optical output 11 via an optical fibre F. Furthermore, the optical output 11 may be a collimator configured to receive radiation from the optical fibre F and to output this as collimated infrared light. Moreover, the radiation generator 10 and the optical output 11 may be configured such that the output, spatially coherent, beam 12 is approximately 0.6mm in diameter and comprises long wavelength infrared light in the region of 1.5 micrometers in wavelength. For instance, the infrared laser diode of the radiation generator 10 maybe a 2 watt maximum output i47onm laser diode.

The inspection block 7 is cylindrical in shape and comprises an inspection hole 17, a first hole 14, a second hole 15 and a rod input 13.

The inspection hole 17 is a cylindrical, coaxial hole in the inspection block 7, of sufficient diameter that the filter rod 8 can be conveyed coaxially through the inspection hole 17 in the direction of the longitudinal axis B of the filter rod 8.

The first hole 14 is a cylindrical hole through the inspection block 7 intersecting and perpendicular to the longitudinal axis A of the inspection block 7.

The second hole 15 is a hole in the cylindrical inspection block 7 extending in a radial direction from the inspection hole 17 to the outer circumference 19 of the inspection block 7. The second hole 15 is in the same plane as the first hole 14 and is

perpendicular to the first hole 14.

The inspection apparatus 1 is configured such that the beam 12 of radiation is output coaxially into a first end 16 of the first hole 14. In more detail, the optical output 11 is mounted on the inspection block 7 at the first end 16 of the first hole 14 so as to achieve the outputting of the beam 12 coaxially into the first end 16 of the first hole 14.

Moreover, the diameter of the first hole 14 is larger than the diameter of the beam 12.

The rod input 13 comprises an end of the inspection hole and is thereby configured to receive the filter rod 8 and arranged so that the filter rod 8 can be conveyed from the rod input 13 through the beam 12 of output radiation in the direction of a longitudinal axis B of the filter rod 8.

The filter rod 8 is shown as having been received by the rod input 13 and as being conveyed through the beam 12 of output radiation in the direction of the longitudinal axis B of the filter rod 8. The beam 12 is transverse and perpendicular to the direction of movement of the filter rod 8 as it is conveyed through the beam 12.

Radiation of the output beam 12 which passes through the filter rod 8 continues along the first hole 14 towards the second end 18 of the first hole 14 at the circumference of the inspection block.

Radiation of the output beam 12 is scattered and in this way redirected within the filter rod 8 and some of this redirected radiation 20 passes through the second hole 15. That is, some radiation 20 is redirected in a direction transverse and perpendicular to the output beam 12 so as to propagate in a direction transverse and perpendicular to the direction of movement of the filter rod 8 as it is conveyed through the output beam 12.

The first receiver 5 is mounted on the inspection block 7 at the second end 18 of the first hole 14, such that the optical output 11 and the first receiver 5 face each other. Moreover, the first receiver 5 is configured to receive radiation of the output beam 12 which has been transmitted through the filter rod 8 and which has reached the second end 18 of the first hole 14.

The second receiver 6 is mounted on the circumferential surface 19 of the inspection block 7 at the second hole 15 and is configured to receive the redirected radiation 20 which passes through the second hole 15. The first receiver 5 and the second receiver 6 are therefore configured to receive radiation output by the same single optical output 11.

The first and second receivers 5, 6 are configured to generate complementary signals P, Q to be analysed in order to provide information relating to the interior of the filter rod 8. Moreover, the first and second receivers 5, 6 are configured to generate the

.complementary signals P, Q as the filter rod 8 is conveyed through the output beam 12. The complementary signals P, Q comprise a first signal P generated by the first receiver

5 and a second signal Q generated by the second receiver 6. Moreover, the first signal P comprises information on the intensity (power per unit area) of radiation received at the first receiver 5 and the second signal Q comprises information on the intensity of radiation received at the second receiver 6. For example, the first and second receivers 5, 6 may each comprise a 3 mm photovoltaic detector. The first and second receivers 5,

6 output their complementary signals P, Q to the processing device 3.

The processing device 3 comprises a processor 21 configured to analyse the received complementary signals P, Q to provide information relating to the interior of the filter rod 8. The information relating to the interior of the filter rod 8 comprises information relating to the presence of the capsules 9 within the filter rod 8. In more detail, the processor 21 is configured to identify one or more variations in the complementary signals P, Q and to assess the identified one or more variations to determine an associated internal variation status. The internal variation status relates an internal feature of the filter rod comprising the presence of a capsule 9 and may for example comprise information relating to the capsule 9 including at least one of a type of the capsule 9, a radial displacement of the capsule 9 relative to the longitudinal axis B of the filter rod 8, a location of the capsule 9 along the length of the filter rod 8, a proper insertion of the capsule 9 within the filter rod 8, a defective insertion of the capsule 9 within the filter rod 8, a condition of the capsule 9, whether the capsule 9 is the correct type of capsule 9, an orientation of the capsule 9, whether the capsule 9 is defective or not, a dimension of the capsule 9, a shape of the capsule 9, a density of the capsule 9 or a spacing of the capsule 9 relative to other determined internal variations. The internal variation status may therefore comprise information relating to characteristics of a capsule 9 determined as being present within the filter rod 8.

Prior to analysis of the received complementary signals P, Q, the processing device 3 may be configured to perform signal processing on the received complementary signals P, Q. For example, the processing device 3 may comprise analogue to digital converters coupled to the outputs of each of the first and second receivers 5, 6.

The configuration of the processor 21 to identify variations in the signals P, Q may for example comprise the processor 21 being configured to detect peaks in each of the signals P, Q. For instance, the processor 21 may normalise and filter the signals P, Q for discrete peaks. Assessing identified variations in order to determine an associated internal variation status may for example comprise assessing detected peaks in the complementaiy signals P, Q in order to identify characteristics of the peaks or a pattern of the peaks associated with the presence and state of a capsule. For instance, the processor 21 may be configured to determine information on characteristics of each identified peak, such as a position along the longitudinal axis B of the filter rod 8 associated with the peak, a position along the filter rod 8 axis B associated with the peak relative to a position along the filter rod 8 axis B associated with another identified peak, a magnitude of the peak, a width of the peak and/or an area of the peak.

The first and second signals P, Q are complementaiy in that the combined information of the two signals P, Q can facilitate the determining of more information relating to the interior of the filter rod 8 than might be determined from either of the signals P, Q alone. For example, in some situations a first type of variation identified in the first signal P may be indicative of a large number of different possible internal features of an inspected filter rod 8. Furthermore, a second type of variation identified in the second signal Q may also be indicative of a large number of possible internal features of the inspected filter rod 8. However, if, in relation to the same location and/or area of the filter rod 8, the first type of variation is identified in the first signal P and the second type of variation is identified in the second signal Q, then this complementary information may be strongly indicative of a single type of internal feature or a reduced set of internal feature types within the filter rod 8.

FIG. 2 shows a schematic view of a machine 22 for inspecting filter rods comprising the inspection apparatus 1 of FIG. 1, a hopper 23 and a conveyer arrangement 24. The machine 22 is configured to receive a batch 25 of filter rods 8 and to automatically inspect each filter rod 8 in turn, as will be described in more detail below.

The hopper 23 is configured to receive the batch 25 of filter rods. The batch 25 of filter rods 8 is shown as having been received by the hopper 23. The filter rods 8 are of the same sort as the filter rod 8 described with reference to FIG.

1.

The conveyer arrangement 24 is configured to receive filter rods successively from the hopper 23 and to convey each received filter rod to and coaxially through the rod input 13, and therein through the output beam 12. The conveyer arrangement 24 comprises a pusher rod 26, a motor 27 and a motor controller 28. FIG. 2 shows a filter rod 8 being conveyed through the inspection hole 17 by the conveyer arrangement 24.

The pusher rod 26 comprises a cylinder coaxially aligned with the inspection hole 17 and of a similar diameter to the filter rods 8 such that it can pass coaxially through the inspection hole.

The motor 27 is configured to move the pusher rod 26 along its longitudinal axis C. Moreover, the motor 27 is configured to output information on the position of the pusher rod 26, herein referred to as rod position information, to the processing device 3 of the inspection apparatus 1. For example, the motor 27 may comprise a rotary encoder.

The motor controller 28 is configured to interface with and control the motor 27. In embodiments, the motor controller is controlled by the processing device 3 of the inspection apparatus 1.

The machine 22 is configured such that movement of the pusher rod 26, by the motor 27, away from the rod input 13 allows a filter rod 8 at the bottom of the hopper 23 to move under the influence of gravity from the hopper 23 to the conveyer arrangement 24, therein being received by the conveyer arrangement 24. Moreover, the machine 22 is configured such that filter rods 8 received by the conveyer arrangement 24 are concentric with the inspection hole 17 and are located between the rod input and the pusher rod 26.

The machine for inspecting filter rods 22 operates as follows. The motor controller 28 instructs the motor 27 to retract the pusher rod 26 such that a filter rod 8 is received by the conveyer arrangement 24 from the hopper 23. The motor controller 28 then instructs the motor 27 to move the pusher rod 26 such that a first end 29 of the pusher rod 26 moves towards and then through the inspection hole 17, in doing so, conveying the received filter rod 8 through the inspection hole 17 and therein through the beam 12. As described with reference to FIG. 1, as the filter rod 8 is conveyed through the beam 12, complementary signals P, Q are generated by the first and second receivers 5, 6 and are analysed by the processor 21 to provide information relating to the interior of the filter rod 8. This process is then repeated until all of the filter rods 8 of the received batch 25 of filter rods have been inspected. Additionally, the processing device 3 of the inspection apparatus 1 is configured to use the received rod position information during the conveying of a filter rod 8 through the output beam 12 to determine a position along the filter rod 8 associated with each identified variation in the complementaiy signals P, Q. As a result, information of each determined internal variation status relating to the presence of a capsule 9 may comprise information on the position of the capsule 9 along the longitudinal axis B of the filter rod 8.

With respect to the machine for inspecting filter rods 22 of FIG. 2, information relating to the interior of inspected filter rods determined by the inspection apparatus 1 may be used to determine quality information relating to the inspected filter rods. For example, determined quality information may indicate that an inspected filter rod is faulty and said filter rod may then be diverted by the machine for recovery of materials or for disposal.

Although FIG. 2 shows an "offline" device having a hopper to receive filter rods to be inspected, alternatively the inspection apparatus could be implemented as an online device as part of a filter rod making machine. For example, in one embodiment a filter rod making machine is provided comprising the inspection apparatus 1, wherein the inspection block 7 is positioned in the path of the elongate filter rod formed in the rod maldng machine so that the elongate rod passes through the inspection hole 17 so as to be analysed by the inspection apparatus 1. FIG. 3 shows a graph illustrating the complementary signals P, Q generated by the inspection apparatus 1 of FIG. 1 as a filter rod 8 is received by the rod input 13 and is conveyed through the output beam 12. The filter rod 8 contains eight capsules 9 separately located along the length of the filter rod 8.

Areas of variation in the first signal P and the second signal Q associated with each capsule 9 are highlighted by a dashed line in each case. The variations of the first signal P associated with each capsule 9 are different from the variations of the second signal Q. For example, the variations of the first signal P, due to the passage of an area of the filter rod 8 rod containing a capsule g through the output beam 12, comprise a temporary increase in the intensity of radiation received, whereas the variations of the second signal Q comprise a temporary decrease in the intensity of radiation received. In this way, the first and second signals P, Q provide complementary information relating to the presence of capsules in rod 8.

It should be understood that the complementary signals P, Q shown in FIG. 3 are an example only. The nature of the complementary signals P, Q, including variations in the signals resulting from a section of an inspected rod article containing an internal feature passing through the output beam 12, may vary depending on a plurality of influencing factors. For example, in the case of a filter rod 8 containing a capsule 9, the plurality of influencing factors may include the properties of the filter rod 8 and the capsule 9, the properties of the beam 12 and the configuration of the receivers 5, 6, Typically the configuration of the apparatus 1 is based on consideration of such influencing factors. For example, the configuration of the processor 21 to identify and assess variations in the complementary signals P, Q may be based on the type of filter rod 8 being inspected and the type of capsules 9 which should be contained therein. Moreover, the configuration of the radiation generator 10 and the optical output 11 may be based on the type of filter rod 8 to be inspected. For instance, it may be appropriate to output a more powerful beam 12 in the case of a larger diameter filter rod 8. Many further alternatives and variations of the above-described embodiments are possible.

For example, the radiation generator 10 and the optical output 11 may be configured to provide the output beam 12 of radiation with different properties to those described. For instance, the radiation generator 10 and the optical output 11 may be configured to provide the output beam 12 of radiation with a different diameter, wavelength or intensity to the examples described herein.

Furthermore, although the optical source 4 is described above as comprising a laser diode coupled to a collimator by an optical fibre, alternatively, the optical source may comprise a laser having a free-space optical output which faces the first receiver. The inspection apparatus 1 is described above as being configured such that the second receiver 6 receives radiation 20 which is redirected in a direction perpendicular to the output beam 12. However, the inspection apparatus 1 maybe configured such that the second receiver 6 receives radiation 20 which is redirected at an angle other than 90 degrees to the output beam 12. For example, the second hole 15 may not be perpendicular to the first hole 14.

An example of the configuration of the processor 21 to identify variations in the signals P, Q is described as the processor 21 being configured to detect peaks in each of the signals. For example, the processor 21 maybe configured to identify Lorentzian function shaped peaks. However, the configuration of the processor 21 to identify variations in the signals P, Q may alternatively or additionally comprise the processor 21 being configured to identify other types of variations to those described. For example, the processor 21 may be configured to identify troughs in the signals P, Q, rates of change in signals or signal exceeding a set signal value threshold.

Furthermore, embodiments have been described with reference to determining information relating to the presence of capsules within a filter rod, but this is not intended to be limiting. In some embodiments, the density of filter tow in a filter rod or the density of tobacco in a tobacco rod could be analysed, or information relating the presence of an object other than a capsule could be determined.

It will be understood that the scattering of radiation as described herein may for example comprise radiation being scattered off of a surface of the capsule or other object and/or radiation being scattered by filter tow material in a filter rod or, in some embodiments, tobacco in a tobacco rod.

Information relating to whether a capsule 9 detected as being present in an inspected filter rod 8 is defective or not may comprise information indicating that the capsule 9 has been crushed or is leaking, burst or ruptured. For example, a lealdng capsule 9 may wet the surrounding material within the containing rod shaped article and this may alter the radiation transmission and scattering/reflection properties of the wetted filter rod material.

The inspection apparatus may be configured to perform the described determining of information on the interior of inspected rod shaped articles of the tobacco industry in real time. In some embodiments, the inspection apparatus 1 may comprise a second inspection unit 2' similar to the first inspection unit 2, as is shown in FIG. 4 and FIG. 5. FIG. 4 shows a schematic sectional view of the inspection apparatus 1 comprising the second inspection unit 2'. FIG. 5 shows a schematic side view of the inspection apparatus 1 of FIG. 4. Due to the vantage point illustrated in FIG. 5, some components of the inspection apparatus 1 maybe obscured from view in this figure.

With reference to FIG. 4 and FIG. 5, the second inspection unit 2' is configured such that the inspection hole 17' of the second inspection unit 2' is coaxial with the inspection hole 17 of the first inspection unit 2. Furthermore, the inspection blocks 7, 7' of the first and second inspection units 2, 2' abut one another. The arrangement of the first and second inspection units 2, 2' can therefore be described as a stacked arrangement or as being stacked. The inspection holes 17, 17' of the first and second inspection blocks 7, 7' together form an overall inspection hole 27 through the inspection blocks 7, 7'. The rod input of the inspection apparatus 1 now comprises an end of the overall inspection hole 27.

The inspection block 7' of the second inspection unit 2! is offset by an angle of rotation R about the axis of the overall inspection hole 27 relative to the inspection block 7 of the first inspection unit. As a result, the beam 12' of the second inspection unit 2' is not parallel with the beam 12 of the first inspection unit 2. The complementary signals P', Q' generated by the receivers 5', 6' of the second inspection unit 2' as the filter rod 8 is conveyed through the inspection hole of the second inspection unit 2' also pass to the processing device 3. Due to the vantage point illustrated in FIG. 5, the second receiver 6' of the second inspection unit 2' is obscured from view.

The processor 21 is configured to analyse the complementary signals P, Q received from the first inspection unit 2 and the complementary signals P', Q' received from the second inspection unit 2' to provide information relating to the interior of the filter rod 8. The combination of the first inspection unit 2 and the second inspection unit 2' can facilitate the determining of more detailed variation status information. For example, the complimentary signals P, Q of the first inspection unit 2 may also be

complementary to those P', Q' of the second inspection unit 2'.

Although the beams 12, 12' of the first and second inspection units 2, 2' are described as being not parallel, the first and second inspection units 2, 2' may instead be arranged such that the beams 12, 12' are parallel but are output in opposing directions.

The radiation generator 10 of the first inspection unit 2 and the radiation generator 10' of the second inspection unit 2' may be the same radiation generator. For example, the output of a single laser diode maybe optically split and thereafter provided to the optical output ll of the first inspection unit 2 and the optical output li' of the second inspection unit 2'.

Although embodiments have been described with reference to the inspection of one or more filter rods 8, they may alternatively or additionally be configured to inspect other types of rod shaped articles of the tobacco industry in the same way. For example, they may be configured to inspect tobacco rods or assembled rod shaped smoldng articles such as cigarettes. Similarly, the herein described machine for manufacturing filter rods, comprising the inspection apparatus 1, maybe a machine for manufacturing other types of rod shaped articles of the tobacco industry.

Furthermore, embodiments have been described with reference to the determining of information relating to the interior of a filter rod 8 comprising information relating to the presence of the capsules 9 within the filter rod 8. However, the inspection apparatus 1 maybe configured to alternatively or additionally determine other types of information relating to the interior of inspected rod shaped articles. For example, the processor 21 may be configured to similarly determine an internal variation status relating to one or more other internal features of the filter rod, such as a density variation, a presence of an object within the article other than a capsule 9, a presence of a cavity within the article, a presence of water or another chemical within the article, or a structural variation. For example, if a filter rod 8 is formed of two different rod shaped filter segments abutting one another, an internal variation status relating to a structural variation may include information relating to a transition from one filter rod segment type to another.

The object within the article other than a capsule 9 may for example comprise a charcoal/cellulose acetate segment. Moreover, the internal variation status relating to the presence of an object within the article other than a capsule 9 may comprise information relating to the object including at least one of a type of the object, a radial displacement of the object relative to the longitudinal axis of the article, a location of the object along the length of the article, a proper insertion of the object within the article, a defective insertion of the object within the article, a condition of the object, whether the object is the correct type of object, an orientation of the object, whether the object is defective or not, a dimension of the object, a shape of the object, a density of the object, or a spacing of the object relative to other determined internal variations. The internal variation status relating the presence of a cavity within the article may for example comprise information on the cavity including at least one of a radial displacement of the cavity relative to the longitudinal axis of the article, a location of the cavity along the length of the article, a proper creation of the cavity within the article, a defective creation of the cavity within the article, a dimension of the cavity, a shape of the cavity, or a spacing of the cavity relative to other determined internal variations.

The internal variation status relating to the presence of water or another chemical within the article may comprise information including at least one of an amount of the water or other chemical within the article, or a location of the water or other chemical within the article. Furthermore, the other chemical may for example be Triacetin.

Referring to FIG. 6, a schematic sectional view of another inspection apparatus 101 for inspecting a rod shaped article 102 of the tobacco industry is shown. FIG. 7 shows a side view of the apparatus of FIG. 6. Due to the vantage point illustrated in FIG. 7, some components of the inspection apparatus 101 may be obscured from view in this figure.

The inspection apparatus 101 is configured to facilitate the determining information (herein referred to in places as "offset information") relating to offset of a non- homogeneity of a received rod shaped article 102 relative to the longitudinal axis D of the received rod shaped article 102. In more detail, the inspection apparatus 101 is configured to pass beams of radiation through the article 102 in different directions and to generate electrical signals based on the intensity of radiation of each of the beams received after interaction of the beam with the rod shaped article 102. Furthermore, the inspection apparatus 101 is configured to process the signals to determine the offset information based on the relative intensity of the radiation which is received from each of the beams.

The inspection apparatus 101 comprises a first inspection unit 103, a second inspection unit 104, a third inspection unit 105, a fourth inspection unit 106, a rod input 107 and a processing device 108. Each inspection unit 103, 104, 105, 106 comprises some components. The components of each inspection unit 103, 104, 105, 106 are as follows: The first inspection unit 103 comprises a first optical source 109, a first receiver 110 and a first inspection block in.

The second inspection unit 104 comprises a second optical source 112, a second receiver 113 and a second inspection block 114. The third inspection unit 105 comprises a third optical source 115, a third receiver 116 and a third inspection block 117.

The fourth inspection unit 106 comprises a fourth optical source 118, a fourth receiver 119 and a fourth inspection block 120.

The inspection units 103, 104, 105, 106 are arranged one after the other as shown in FIG. 7 and define an overall inspection hole in the form of a longitudinal passage 134 through which the rod-shaped article passes as it is inspected.

A rod shaped article 102 is shown as having been received by the inspection apparatus

101 and as being inspected. The rod shaped article 102 is a cellulose acetate filter rod

102 comprising one or more capsules 121 embedded therein. The capsule 121 may for example be substantially spherical, formed from gelatin and contain a flavourant, for example menthol, spearmint, orange essence, mint, liquorice, eucalyptus, one or more of a variety of fruit flavours or any mixture of flavourants. By applying pressure to the outside of the filter rod 102 the capsule 121 can be ruptured, thereby releasing the flavourant. Released flavourant can act to flavour smoke drawn through the filter rod 102 when it is incorporated in a smoking article such as a cigarette.

Each of the first, second, third and fourth optical sources 109, 112, 115, 118 comprise a radiation generator 122a, 122b, 122c, i22d and an optical output 123a, 123b, 123c, 123d. Each radiation generator 122a, 122b, 122c, i22d is configured to generate radiation and to provide this to its associated optical output 123a, 123b, 123c, 123d. Each optical output 123a, 123b, 123c, 123d is configured to receive the generated radiation from its associated radiation generator 122a, 122b, 122c, i22d and to output a beam 124, 125, 126, 127 of the generated radiation.

The optical output 123a of the first optical source 109 outputs a first beam 124 in a first direction. The optical output 123b of the second optical source 112 outputs a second beam 125 in a second direction. The optical output 123c of the third optical source 115 outputs a third beam 126 in a third direction.

The optical output 123d of the fourth optical source 118 outputs a fourth beam 127 in a fourth direction.

The first, second, third and fourth beams 124, 125, 126, 127 are of the same diameter.

For example, with reference to the first optical source 109, the radiation generator 122a of the first optical source 109 maybe an infrared laser diode configured to provide the generated infrared light to the optical output 123a of the first optical source 109 via an optical fibre Ga. Furthermore, the optical output 123a may be a collimator configured to receive the radiation generated by the radiation generator 122a and to output this as collimated infrared light. Moreover, the associated radiation generator 122a and optical output 123a maybe configured such that the output, spatially coherent, first beam 124 is approximately 0.6mm in diameter and comprises long wavelength infrared light in the region of 1.5 micrometers in wavelength. For instance, the infrared laser diode of the radiation generator 122a may be a 2 watt maximum output i47onm laser diode. This example may apply similarly to one or more of the second, third or fourth optical source 112, 115, 118.

The first inspection block ill is cylindrical in shape and comprises an inspection hole 128a and a beam hole 129a.

The inspection hole 128a is a cylindrical, concentric hole in the first inspection block ill of sufficient diameter to permit the filter rod 102 to be conveyed coaxially through the inspection hole 128a in the direction of the longitudinal axis D of the filter rod 102.

The beam hole 129a is a cylindrical hole through the first inspection block 111 intersecting and perpendicular to the longitudinal axis E of the cylindrical first inspection block 111.

The diameter of the beam hole 129a of the first inspection block ill is larger than the diameter of the first beam 124.

The second, third and fourth inspection blocks 114, 117, 120 are identical to the first inspection block ill, but are orientated at different angles as shown in FIG. 7. The first optical output 123a is mounted on the first inspection block 111 at a first end 130 of the beam hole 129a of the first inspection block in and outputs the first beam 124 coaxially into the beam hole 129a.

The second optical output 123b is mounted on the second inspection block 114 at a first end 131 of the beam hole 129b of the second inspection block 114 and outputs the second beam 125 coaxially into the beam hole 129b.

The third optical output 123c is mounted on the third inspection block 117 at a first end 132 of the beam hole 129c of the third inspection block 117 and outputs the third beam 126 coaxially into the beam hole 129c. The fourth optical output 123d is mounted on the fourth inspection block 120 at a first end 133 of the beam hole l29d of the fourth inspection block 120 and outputs the fourth beam 127 coaxially into the beam hole l29d.

The first inspection block 111, second inspection block 114, third inspection block 117 and fourth inspection block 120 abut each other in that order such that the inspection holes 128a, 128b, 128c, I28d of the inspection blocks 111, 114, 117, 120 share a common axis.

The inspection holes 128a, 128b, 128c, I28d of the first, second, third and fourth inspection blocks 111, 114, 117, 120 together form an overall inspection hole 134 through the inspection blocks 111, 114, 117, 120. The rod input 107 comprises an end of the overall inspection hole 134.

The rod input 107 is therefore configured to receive the filter rod 102 and arranged so that the filter rod 102 can be conveyed from the rod input 107 through the beams 124, 125, 126, 127 in the direction of a longitudinal axis D of the filter rod 102.

The inspection blocks ill, 114, 117, 120 are arranged relative to each other such that the first, second, third and fourth beams 124, 125, 126, 127 are angularly offset from each other about the longitudinal axis E of the overall inspection hole 134 at 45 degree intervals.

The filter rod 102 is shown as having been received by the rod input 107 and as being conveyed from the rod input 107, through the first, second, third and fourth beams 124, 125, 126, 127 in the direction of the longitudinal axis D of the filter rod 102. Each of the first, second, third and fourth beam 124, 125, 126, 127 is transverse and perpendicular to the direction of movement of the filter rod 102 as it is conveyed through the beams 124, 125, 126, 127.

The first receiver 110 is mounted on the circumference of the first inspection block 111 at a second end 135 of the beam hole 129a of the first inspection block 111. Moreover, the first receiver 110 is configured to receive radiation of the output first beam 124 which has been transmitted through the filter rod 102 and which has reached the second end 135 of the beam hole 129a.

The second receiver 113 is mounted on the circumference of the second inspection block 114 at a second end 136 of the beam hole 129b of the second inspection block 114. Moreover, the second receiver 113 is configured to receive radiation of the output second beam 125 which has been transmitted through the filter rod 102 and which has reached the second end 136 of the beam hole 129b.

The third receiver 116 is mounted on the circumference of the third inspection block 117 at a second end 137 of the beam hole 129c of the third inspection block 117. Moreover, the third receiver 116 is configured to receive radiation of the output third beam 126 which has been transmitted through the filter rod 102 and which has reached the second end 137 of the beam hole 129c.

The fourth receiver 119 is mounted on the circumference of the fourth inspection block 120 at a second end 138 of the beam hole l29d of the fourth inspection block 120. Moreover, the fourth receiver 119 is configured to receive radiation of the output fourth beam 127 which has been transmitted through the filter rod 102 and which has reached the second end 138 of the beam hole l29d.

The first receiver 110 is configured to generate a first signal H as the filter rod 102 is conveyed through the first beam 124. The second receiver 113 is configured to generate a second signal I as the filter rod 102 is conveyed through the second beam 125.

The third receiver 116 is configured to generate a third signal J as the filter rod 102 is conveyed through the third beam 126. Due to the vantage point illustrated in FIG. 7, the third receiver 116 is obscured from view and is therefore not shown in this figure. The fourth receiver 119 is configured to generate a fourth signal K as the filter rod 102 is conveyed through the fourth beam 127. Each signal H, I, J, K comprises a voltage proportional to the intensity of radiation received at the receiver lio, 113, 116, 119 generating that signal. For example, the second signal I comprises a voltage proportional to the intensity of radiation received at the second receiver 113. The receivers 110, 113, 116, 119 may, for example, each comprise a 3 mm photovoltaic detector. The first, second, third and fourth receivers 110, 113, 116, 119 output their signals H, I, J, Kto the processing device 108.

The processing device 108 comprises a processor 139 configured to process the received signals H, I, J, K in order to determine offset information. Determining of the offset information by the processor is based on the relative intensity of the radiation received at the receivers, as indicated by the signals.

As the received filter rod 102 is conveyed through the beams 124, 125, 126, 127, each time a region of the filter rod 102 containing a capsule 121 passes through one of the beams, dependent on the location of the capsule 121 within the filter rod 102, the presence of the capsule 121 may affect the transmission of that beam through the filter rod 102. For example, if a first capsule is located within the filter rod 102 such that it is aligned with or near the first beam 124 as the region of the filter rod 102 containing the first capsule passes through the first beami24, then the presence of the capsule causes a decrease in the intensity of radiation of the first beam 124 passing through the filter rod 102. To illustrate how the processor 139 determines the offset information by processing the signals H, I, J, K, FIG. 8 shows a cross-section through the filter rod 102 at a capsule 121 within the filter rod 102. Furthermore, FIG. 8 illustrates cross-sectional regions Ri, R2, R3, R4, R5, R6, R7, R8 and R9 of the filter rod 102. Moreover, for each cross- sectional region, Table 1 indicates the relative magnitudes of the voltages which would be generated by each of the receivers 110, 113, 116, 119, in response to the received optical radiation and in proportion to an intensity thereof, if the capsule 121 were located in that cross-sectional region. In other words, Table 1 illustrates the relative intensity of radiation that would be received at the receivers for different cross- sectional locations of the capsule. Table 1

Cross-sectional region Relative magnitudes of the voltage values

at which the capsule of the first, second, third and fourth 121 is located signals H, I, J, K

Rl H » I « J * K

R2 H < (I, K) < J

R3 I < (H, J) < K

R₄ J < (I, K) < H

R5 K < (H, J) < I

R6 (H, I) < (J, K)

R₇ (I, J) < (H, K)

R8 (J, K) < (H, I)

R9 (H, K) < (I, J)

For example, Table l shows that if the capsule 121 is located anywhere in region R6, then it will affect the transmission of the beams 124, 125, 126, 127 through the filter rod 102 such that the voltages generated by each of the first and second receivers 110, 113 are less than the voltage generated by either of the third and fourth receivers 116, 119. Moreover, the voltages values of the first and second signals H, I will be approximately equal and the voltages values of the third and fourth signals J, K will be approximately equal.

The processor is configured to process the signals to determine offset information indicating the cross-sectional region of a capsule in the filter rod in accordance with Table 1.

For example, if the processor 139 determines that voltage value of each of the first and third signals H, J is greater than that of the fourth signal K but less than that of the second signal I, then the processor 139 determines offset information indicating that the capsule 121 is in region R5.

Regions R2 to R5 are further from the axis D of the filter rod 102 than region Rl.

Regions R6 to R9 are further from the axis D of the filter rod 102 than regions R2 to R5. The determined offset information therefore comprises information relating to the radial distance of the capsule 121 from the longitudinal axis D of the filter rod 102.

If the capsule 121 is located such that it is accurately aligned with one of the beams 124, 125, 126, 127 it will cause the intensity of the radiation of that beam passing through the filter rod 102 to decrease by a certain amount X. The processor 139 is configured to identify when a signal H, I, J, K indicates that the intensity of transmitted radiation of a beam has decreased by this amount X and to determine from this that the capsule 121 is accurately aligned with the beam. The offset information determined by the processor 139 may therefore include information indicating that the capsule 121 is located within the filter rod 102 such that it is aligned with one or more of the beams 124, 125, 126, 127.

Prior to analysis of the received signals H, I, J, K, the processing device 108 may be configured to perform signal processing on the received signals. For example, the processing device 108 may comprise analogue to digital converters coupled to the outputs of each of the first and second receivers 110, 113.

FIG. 9 shows a schematic view of a machine 140 for inspecting filter rods comprising the inspection apparatus 101 of FIG. 6, a hopper 141 and a conveyer arrangement 142. The machine 140 is configured to receive a batch 143 of filter rods 102 and to automatically inspect each filter rod 102 in turn, as will be described in more detail below.

The hopper 141 is configured to receive the batch 143 of filter rods 102. The batch 143 of filter rods 102 is shown as having been received by the hopper 141.

The filter rods 102 are of the same sort as the filter rod 102 described with reference to FIG. 6 to FIG. 8. The conveyer arrangement 142 is configured to receive filter rods 102 successively from the hopper 141 and to convey each received filter rod 102 to and coaxially through the rod input 107, and therein through the beams 124, 125, 126, 127. The conveyer arrangement 142 comprises pusher rod 144, and motor 145 and a motor controller 146. FIG. 9 shows a filter rod 102 being conveyed through the rod input 107 by the conveyer arrangement 142. The pusher rod 144 comprises a cylinder, the axis of which is aligned with the axis of the overall inspection hole 134, of a similar diameter to the filter rods 102 such that it can pass coaxially through the overall inspection hole 134.

The motor 145 is configured to move the pusher rod 144 along its longitudinal axis F. Moreover, the motor 145 is configured to output information on the position of the pusher rod 144, herein referred to as rod position information, to the processing device 108 of the inspection apparatus 101. For example, the motor 145 may comprise a rotary encoder.

The motor controller 146 is configured to interface with and control the motor 145. In embodiments, the motor controller 146 is controlled by the processing device 108 of the inspection apparatus 101.

The machine 140 is configured such that movement of the pusher rod 144, by the motor 145, away from the rod input 107 allows a filter rod 102 at the bottom of the hopper 141 to move under the influence of gravity from the hopper 141 to the conveyer

arrangement 142, therein being received by the conveyer arrangement 142. Moreover, the machine 140 is configured such that filter rods 102 received by the conveyer arrangement 142 are concentric with the rod input 107 and are located between the rod input 107 and the pusher rod 144.

The machine 140 for inspecting filter rods operates as follows. The motor controller 146 instructs the motor 145 to retract the pusher rod 144 such that a filter rod 102 is received by the conveyer arrangement 142 from the hopper 141. The motor controller 146 then instructs the motor 145 to move the pusher rod 144 such that a first end 147 of the pusher rod 144 moves towards and then through the rod input 107, in doing so, conveying the received filter rod 102 through the overall inspection hole 134 and therein through the first, second, third and fourth beams 124, 125, 126, 127. As described with reference to FIG. 6, as the filter rod 102 is conveyed through the first, second, third and fourth beams 124, 125, 126, 127, signals H, I, J, K are generated by the receivers no, 113, 116, 119 and are processed by the processor to determine the offset information. This process is then repeated until all of the filter rods 102 of the received batch 143 of filter rods have been inspected.

Additionally, the processing device 108 of the inspection apparatus 101 is configured to use the received rod position information during the conveying of a filter rod 102 through the beams 124, 125, 126, 127 to associate instances within each received signal H, I, J, K with corresponding positions along the filter rod 102. As a result, the offset information may comprise information on the position of the capsule 121 along the longitudinal axis D of the filter rod 102. With respect to the machine 140 for inspecting filter rods of FIG. 9, the offset information relating to capsules 121 within the inspected filter rods 102 determined by the inspection apparatus 101 may be used to determine quality information relating to the inspected filter rods 102. For example, determined quality information may indicate that an inspected filter rod is faulty and said filter rod 102 may then be diverted by the machine for recovery of materials or for disposal.

Although FIG. 9 shows an "offline" device having a hopper to receive filter rods to be inspected, alternatively the inspection apparatus 101 could be implemented as an online device as part of a filter rod making machine. For example, in one embodiment a filter rod making machine is provided comprising the inspection apparatus 101, wherein the inspection blocks ill, 114, 117, 120 are positioned in the path of the elongate filter rod formed in the rod making machine so that the elongate rod passes through the overall inspection hole 134 so as to be analysed by the inspection apparatus 101.

Many alternatives and variations of the embodiments described above with reference to FIG. 6 to FIG. 9 are possible.

For example, the radiation generators 122a, 122b, 122c, l22d and the optical outputs 123a, 123b, 123c, 123d may be configured so as to output a beam 124, 125, 126, 127 of radiation with different properties to those described. For instance, the first radiation generator 122a and the first optical output 123a may be configured to provide the first beam 124 of radiation with a different diameter, wavelength or intensity to the examples described herein.

Furthermore, although the optical sources 109, 112, 115, 118 are described with reference to FIG. 6 to FIG. 9 as comprising a laser diode 122a, 122b, 122c, l22d coupled to a collimator 123a, 123b, 123c, 123d by an optical fibre Ga, Gb, Gc, Gd, alternatively, the optical sources may each comprise a laser having a free-space optical output.

The rod input 107 is described with reference to FIG. 6 to FIG. 9 as comprising an end of the overall inspection hole 134. However, other types of rod input 107 are possible while still being configured to receive the filter rod 102 and arranged so that the filter rod 102 can be conveyed from the rod input 107 through the first, second, third and fourth beams 124, 125, 126, 127 of radiation in the direction of a longitudinal axis B of the filter rod 102. The inspection apparatus 101 may be configured to perform the described determining of information relating to offset of non-homogeneities relative to the longitudinal axis of an inspected rod shaped article 102 of the tobacco industry in real time.

The inspection apparatus 101 is described above as comprising four inspection units 103, 104, 105, 106. However, the inspection apparatus 101 may comprise any plurality of inspection units. For example, the inspection apparatus 101 may comprise only two or three inspection units.

The arrangement of the first, second, third and fourth inspection units 103, 104, 105, 106 can be described as a stacked arrangement or as being stacked.

The inspection blocks ill, 114, 117, 120 are described above as being arranged relative to each other such that the first, second, third and fourth beams 124, 125, 126, 127 are angularly offset from each other about the longitudinal axis of the overall inspection hole 134 at 45 degree intervals. However, the inspection apparatus 101 may be configured such that the first, second, third and fourth beams 124, 125, 126, 127 are differently angularly offset from each other about the longitudinal axis of the overall inspection hole 134.

The radiation generators 122a, 122b, 122c, l22d may be the same radiation generator. For example, the output of a single laser diode may be optically split and thereafter provided to the optical output 123a, 123b, 123c, 123d of each of the first, second, third and fourth inspection units 103, 104, 105, 106. Embodiments described with reference to FIG. 6 to FIG. 9 are described with reference to the determining of offset information relating to the location capsules 121 within the filter rod 102. However, the inspection apparatus 101 may be configured to similarly determine offset information relating to the location of other types of non- homogeneities of the filter rod 102. For example, the inspection apparatus 101 may alternatively or additionally be configured to similarly determine offset information relating to the location of an object other than a capsule 121 within an inspected filter rod 102, for instance a charcoal/cellulose acetate segment or an area comprising a chemical suc as water. Alternatively or additionally, the inspection apparatus 101 may be configured to similarly determine offset information relating to the location of a cavity or a density variation within an inspected filter rod 102.

The radiation generators 122a, 122b, 122c, l22d maybe configured such that the radiation of the output beams 124, 125, 126, 127 is at a wavelength that has a high propensity to be absorbed by a non-homogeneity of interest.

Although embodiments have been described with reference to the inspection of one or more filter rods 102, they may alternatively or additionally be configured to inspect other types of rod shaped articles of the tobacco industry and to determine offset information as described. For example, they may be configured to inspect tobacco rods or assembled rod shaped smoking articles such as cigarettes. Similarly, the herein described machine 140 for manufacturing filter rods 102, comprising the inspection apparatus 101, maybe a machine for manufacturing other types of rod shaped articles of the tobacco industry. It should be understood that the described effect of the presence of a capsule 121 on the intensity of radiation passing through the filter rod 102 is an example only. The nature of the signals H, I, J, K, including variations in the signals resulting from a section of an inspected rod article 102 containing a feature, such as a capsule 121, passing through the output beams 124, 125, 126, 127 may vary depending on a plurality of influencing factors. For example, in the case of a filter rod 102 containing a capsule 121, the plurality of influencing factors may include the properties of the filter rod 102 and the capsule 121 (e.g. whether the capsule is full or empty), the properties of the output beams 124, 125, 126, 127, and the configuration of the receivers 110, 113, 116, 119. The presence of a capsule 121 in a region of filter rod 102 passing through one of the beams 124, 125, 126, 127 may, for example, cause a variation in the intensity of radiation passing through the filter rod 102. Typically the configuration of the apparatus 101 is based on consideration of such influencing factors. For example, the configuration of the processor 139 to evaluate the relative intensities of radiation received at the receivers by processing the signals H, I, J, K may be based on the type of filter rod 102 being inspected and the type of capsules 121 which should be contained therein.

Moreover, the configuration of the radiation generators 122a, 122b, 122c, I22d and the optical outputs 123a, 123b, 123c, 123d may be based on the type of filter rod 102 to be inspected. For instance, it maybe appropriate to output a more powerful beam 112 in the case of a larger diameter filter rod 102. The first, second, third and fourth inspection blocks 111, 114, 117, 120 may not be identical.

The inspection apparatus 101 may be configured such that the first, second, third and fourth beams 124, 125, 126, 127 are not staggered. For example, this is illustrated by FIG. 10 which shows the inspection apparatus 101 configured such that each of the first, second, third and fourth inspection units 103, 104, 105, 106 share a single, common inspection block 148. The common inspection block 148 is configured such that the first, second, third and fourth beams 124, 125, 126, 127 share a common plane of the inspection block and therein substantially intersect each other within the inspection hole 134 of the common inspection block 148. To reduce the affect of mutual interference between the different inspection units 103, 104, 105, 106, which may result from redirection of radiation of one of the beams 124, 125, 126, 127 by a region of the received filter rod 102 towards a receiver 110, 113, 116, 119 associated with a different beam, the inspection apparatus 101 comprises optical filters 149a, 149b, 149c, l49d. In more detail, each inspection unit 103, 104, 105, 106 is configured to output its beam 124, 125, 126, 127 at a different wavelength to that of the other inspection units.

Moreover, each inspection unit 103, 104, 105, 106 comprises an optical filter 149a, 149b, 149c, I49d configured to allow only radiation at the wavelength of its associated beam to reach its receiver 110, 113, 116, 119. For example, the optical filter 149a of the first inspection unit 103 is configured to allow only radiation from the inspection hole 134 which is at the same wavelength as that of the first beam 124 to reach the first receiver 110.

It should be understood that, in embodiments, determining by the processor of information relating to offset of one or more non-homogeneities within a rod shaped article relative to the longitudinal axis of the rod shaped article may comprise the processor determining information indicating that a capsule is in one of a plurality of regions of a cross sectional area of the filter rod. Moreover, offset information may comprise information relating to the distance of a non-homogeneity from the longitudinal axis of the rod shaped article. Furthermore, offset information may comprise information indicating that a non-homogeneity is not offset from the longitudinal axis of an inspected rod shaped article.

Many alternatives and variations of the embodiments described herein are possible. For example, the receivers 5, 5', 110, 113, 116, 119 may comprise other types of photodetectors from those described.

Reference herein to a cellulose acetate filter rod 8, 102 may for example be replaced by a reference to filter rods 8, 102 comprising other types of filter material. Reference herein to capsules 9, 121 could be interchanged with a reference to other types of capsule.

Furthermore, the rod input 13, 107 may be configured to receive different rod shaped articles 8, 102 of the tobacco industry, for example rods having different diameters and/or non-circular cross-sections. The inspection blocks 7, 7', 111, 114, 117, 120 are described above as being cylindrical in shape, having a circular cross-section. However, the inspection blocks 7, 7', ill, 114, 117, 120 may be of a different cross-section shape, for instance the inspection blocks may be octagonal in cross-section.

Mention is made herein to intersection of different beams of radiation. It should be understood, that this may involve the different beams of radiation overlapping.

In order to address various issues and advance the art, the entirety of this disclosure shows by way of illustration various embodiments in which the claimed invention(s) maybe practiced and provide for superior inspection of rod shaped articles of the tobacco industry. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and/or exclusive. They are presented only to assist in understanding and teach the claimed features. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects of the disclosure are not to be considered limitations on the disclosure as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope and/or spirit of the disclosure. Various embodiments may suitably comprise, consist of, or consist essentially of, various combinations of the disclosed elements, components, features, parts, steps, means, etc. In addition, the disclosure includes other inventions not presently claimed, but which may be claimed in future. Any feature of any embodiment can be used independently of, or in combination with, any other feature.

Claims

Claims l. Apparatus for inspecting a rod shaped article of the tobacco industry, comprising:

an optical output configured to output a beam of electromagnetic radiation; a first receiver for receiving radiation which has been output by the optical output and transmitted through the rod shaped article, wherein the optical output and the first receiver face each other;

a second receiver for receiving radiation which has been output by the optical output and redirected within the rod shaped article; and

wherein the first and second receivers are configured to generate

complementary signals to be analysed to provide information relating to the interior of the rod shaped article.

2. The apparatus of claim l, comprising

a rod input configured to receive the rod shaped article and arranged so that the rod can be conveyed from the rod input through the beam of output radiation in the direction of a longitudinal axis of the article, wherein the first and second receivers are configured to generate said complemetary signals as the rod shaped aiticle is conveyed through the beam.

3. The apparatus of claim 2, configured such that the output beam of radiation is transverse to the direction of movement of the article as it is conveyed.

4. The apparatus of claim 2 or 3, configured such that the radiation which has been output by the optical output and redirected within the rod shaped article is redirected in a direction transverse to the direction of movement of the article as it is conveyed.

5. The apparatus of any preceding claim, comprising a processor configured to analyse the complementary signals to provide information relating to the interior of the rod, wherein analysing comprises assessing one or more variations in the signals in order to determine an internal variation status.

6. The apparatus of claim 5, wherein the internal variation status relates to an internal feature of the rod, including of a density variation, a presence of an object within the article, a presence of a cavity within the article, a presence of water or another substance within the article, or a structural variation.

7. The apparatus of claim 6, wherein the internal variation status relates to the presence of an object within the article, and comprises information relating to the object including at least one of:

a type of the object,

a location of the object within the article,

a proper insertion of the object within the article,

a defective insertion of the object within the article,

a condition of the object,

whether the object is the correct type of object,

an orientation of the object,

whether the object is defective or not,

a dimension of the object,

a shape of the object,

a density of the object, or

a spacing of the object relative to other determined internal variations.

8. The apparatus of claim 7, wherein the object comprises a capsule, or a charcoal/cellulose acetate segment.

9. The apparatus of any one of claims 6 to 8, wherein the internal variation relates to the presence of a cavity within the article and comprises information on the cavity including at least one of:

a location of the cavity within the article,

a proper creation of the cavity within the article,

a defective creation of the cavity within the article,

a dimension of the cavity,

a shape of the cavity, or

a spacing of the cavity relative to other determined internal variations.

10. The apparatus of any one of claims 6 to 9, wherein the internal variation status relates to the presence of water or another substance within the article and comprises information including at least one of:

an amount of the water or other substance within the article, or a location of the water or other substance within the article.

11. The apparatus of claim 10, wherein the other substance is Triacetin.

12. The apparatus of any preceding claim, comprising a second optical output configured to output a beam of electromagnetic radiation;

a third receiver for receiving radiation which has been output by the second optical output and transmitted through the rod shaped article, wherein the second optical output and the third receiver face each other;

a fourth receiver for receiving radiation which has been output by the second optical output and redirected within the rod shaped article; and

wherein the third and fourth receivers are configured to generate

complementary signals to be analysed to provide information relating to the interior of the article.

13. The apparatus of claim 13, wherein the signals of the third and fourth receivers are also complementary to the signals of the first and second receivers.

14. An apparatus for inspecting a rod shaped article of the tobacco industry, the article including one or more non-homogeneities, comprising:

a first inspection unit configured to inspect in a first direction;

a second inspection unit configured to inspect in a second direction different to the first direction; and

a processor; wherein:

the first inspection unit comprises a first optical output and a first receiver, and the second inspection unit comprises a second optical output and a second receiver;

the first optical output is configured to output a first beam of electromagnetic radiation in the first direction and the second optical output is configured to output a second beam of electromagnetic radiation in the second direction;

each of the first receiver and the second receiver is configured to generate a signal comprising information on the intensity of radiation received;

the apparatus is configured to receive a rod shaped article and is arranged such that the received rod shaped article can be conveyed through the first beam and the second beam in the direction of a longitudinal axis of the rod shaped article; and

the processor is configured to process the signals to determine information relating to offset of one or more non-homogeneities relative to the longitudinal axis of the received rod shaped article, based on the relative intensity of the radiation which is received at the first and second receivers.

15. The apparatus of claim 14, wherein the determined information relating to offset of the one or more non-homogeneities comprises information indicating that at least one of said non-homogeneities is in one of a plurality of regions of a cross sectional area of the rod shaped article.

16. The apparatus of claim 14 or 15, configured such that the first beam is transverse to the direction of movement of the article as it is conveyed.

17. The apparatus of claim 14, 15 or 16, configured such that the second beam is transverse to the direction of movement of the article as it is conveyed.

18. The apparatus of any one of claims 14 to 17, configured such that the radiation output in the first direction substantially intersects the radiation output in the second direction.

19. The apparatus of claim 18, wherein the first optical output is configured to output radiation at a first wavelength and the second optical output is configured to output radiation at a second wavelength, and the first and second wavelengths are substantially different; and

comprising a first optical filter and a second optical filter, wherein the first optical filter is configured to prevent radiation at the second wavelength from reaching the first receiver, and the second optical filter is configured to prevent radiation at the first wavelength from reaching the second receiver.

20. The apparatus of any one of claims 14 to 17, configured such that the first beam does not substantially intersect the second beam.

21. The apparatus of any one of claims 14 to 20, comprising a third inspection unit configured to inspect in a third direction; wherein:

the third inspection unit comprises a third optical output and a third receiver;

the third optical output is configured to output a third beam of electromagnetic radiation in the third direction;

the third receiver is configured to generate a signal comprising information on the intensity of radiation received;

the apparatus is arranged such that the received rod shaped article can be conveyed through the third beam in the direction of a longitudinal axis of the rod shaped article; and

the processor is configured to process the signals from the first, second and third receivers to determine information relating to offset of one or more non- homogeneities relative to the longitudinal axis of the received rod shaped article, based on the relative intensity of the radiation which is received at the first, second and third receivers.

22. The apparatus of any preceding claim, wherein the optical output(s) are configured to output electromagnetic radiation comprising infrared light.

23. A method of determining information relating to offset of one or more non- homogeneities of a rod shaped article relative to a longitudinal axis of the rod shaped article, the method comprising:

receiving a first signal comprising information on the intensity of radiation passing through the rod shaped article in a first direction;

receiving a second signal comprising information on the intensity of radiation passing through the rod shaped article in a second direction;

processing the signals to determine information relating to offset of the one or more non-homogeneities relative to the longitudinal axis of the received rod shaped article, based on the relative intensity of the radiation which is received at the first and second receivers.

24. Tobacco industry apparatus for manufacturing a rod shaped article, comprising an apparatus for inspecting the rod shaped article as claimed in any preceding claim.

25. The apparatus of claim 24, wherein the tobacco industiy apparatus comprises a filter rod maker.

26. The apparatus of claim 24, wherein the tobacco industry apparatus comprises tobacco rod maker.

27. The apparatus of claim 24, wherein the tobacco industry apparatus comprises cigarette assembler.