GB2138266A - Pneumatic testing apparatus for cigarettes or the like - Google Patents

Abstract

Apparatus for testing the wrappers of filter cigarettes in a filter tipping machine has a drum-shaped conveyor with peripheral flutes which transport a succession of cigarettes through a testing station where the ends of successive cigarettes receive compressed air to establish a pressure differential between the interior and the exterior of satisfactory wrappers. At the testing station, the ends of the cigarettes are sealed from the atmosphere by first sealing devices having elastically deformable annular portions surrounding the filters of the cigarettes in the regions adjacent to the respective end faces and second sealing devices having elastically deformable membranes engaging the end faces of the tobacco containing portions of the cigarettes. The air is caused to flow through openings which are provided in the sealing devices. Such selection of sealing devices ensures that minor defects at those ends of the wrappers which surround the filters do not result in segregation of corresponding cigarettes from other cigarettes. Segregation is effected automatically by monitoring the pressure differential between the interior and the exterior of each wrapper at the testing station and by ejecting cigarettes whose wrappers permit excessive quantities of air to flow therethrough or therearound. <IMAGE>

Description

SPECIFICATION Pneumatic testing apparatus for cigarettes or the like The present invention relates to improvements in apparatus for testing cigarettes and/or analogous rod-shaped articles, especially rod-shaped articles of the tobacco processing industry. More particularly, the invention relates to improvements in pneumatic testing apparatus for the wrappers of plain or filter cigarettes or the like.

It is well known to test cigarettes or analogous rod-shaped articles (hereinafter referred to as cigarettes or filter cigarettes) by causing them to move sideways (i.e., at right angles to their respective axes) while being received in axially parallel flutes at the periphery of a rotary drum-shaped testing conveyor which transports successive cigarettes through a testing station where the cigarette wrappers are tested for integrity by establishing a pressure differential between the interior and the exterior of their wrappers.This is normally achieved by connecting each end of the cigarette at the testing station with a discrete sealing device which seals the respective end of a satisfactory cigarette from the surrounding atmosphere so that compressed testing fluid can be introduced into the wrapper of the cigarette by way of the one and/or the other sealing device in order to raise the pressure in the interior of the cigarette above atmospheric pressure. If the cigarette is satisfactory (i.e., if its wrapper is acceptable), the pressure in the interior of the wrapper will rise to a certain value, and such pressure is monitored buy a suitable transducer to allow for preferably automatic segregation of cigarettes which have wrappers exhibiting open seams, frayed ends, one or more holes and/or a combination of such defects.

Testing apparatus of the above outlined character are combined with or incorporated into machines for the making of plain cigarettes or into filter tipping machines wherein plain cigarettes are united with filter plugs to form filter cigarettes of unit length or multiple unit length. Typical examples of popular filter tipping machines are those known as MAX and MAX S (both manufactured and sold by the assignee of the present application).

Testing apparatus of the above outlined or similar character are also necessary to ascertain the extent to which the wrappers of cigarettes admit cool atmospheric air into the column of tobacco smoke.

The making of perforations in the wrappers of cigarettes is preferred and actually demanded by many makers of filter cigarettes because the admixture of cool atmospheric air into the column of hot tobacco smoke is believed to reduce the presumably deleterious effects of nicotine, condensate and other ingredients of tobacco smoke. The rate of admission of atmospheric air must be maintained within a very narrow range, and this is ensured by testing the filter cigarettes and immediately changing the combined cross-sectional area of perforations if the rate of admission of atmospheric air is insufficient or excessive.

It will be readily appreciated that satisfactory test results cannot be obtained if the cigarettes at the testing station are not properly sealed from the surrounding atmosphere, i.e., when the pressure increase or pressure drop in the interior of or around the wrapper at the testing station is not accurately indicative of the quality of the wrapper. This can result in ejection of satisfactory cigarettes or in retention of unsatisfactory cigarettes among satisfactory articles with resulting annoyance to the purchasers. German Offenlegungsschrift No. 2444 708 discloses a testing apparatus which employs sealing devices serving to bear against the end faces of the cigarettes during testing. Such mode of sealing both ends of a wrapper from the surrounding atmosphere is acceptable as long as the ends of the wrapper are intact.However, if the ends of the wrapper are frayed, torn or otherwise damaged, the placing of sealing elements against the end faces of the cigarettes cannot ensure adequate sealing of the interior of the wrapper from the atmosphere, i.e., the apparatus is likely to invariably generate an "eject" signal even if the condition of the one or the other end portion of the wrapper is still acceptable. Similar problems arise if the ends of the wrappers are satisfactory but the end faces of the cigarette are not located in planes which are exactly normal to the axis of the cigarette. Again and again, testing apparatus employing such sealing devices will cause ejection of satisfactory articles with attendant losses in output.

German Offenlegungsschriften 2442962 and 31 40 812 disclose cigarette testing apparatus wherein the sealing devices for the ends of the cigarettes resemble cups which are designed to engage the peripheral surfaces in the region of the respective ends of the rod-shaped articles. Such types of sealing devices greatly reduce the likelihood of segregation of articles whose wrappers are generally acceptable even though somewhat frayed or otherwise less than perfect; however, they also bring about the danger of retention of large numbers of unsatisfactory cigarettes among those which are acceptable for packaging and/or other processing, especially cigarettes wherein the ends of the wrappers are damaged to an extent that would normally warrant segregation of such articles from satisfactory goods.Excessive fraying of the ends of cigarette wrappers is unacceptable for esthetic reasons and also because particles of tobacco are more likely to escape at the respective ends.

Cupped sealing devices for the end portions of wrappers forming part of cigarettes or analogous rod-shaped articles are further disclosed in commonly owned copending patent application Serial No. filed February 8, 1984 by Wolfgang Siems, in commonly owned U.S. Pat. No. 3,914,989 granted October 1975 to Reuland et al., and in commonly owned U.S. Pat. No. 3,769,832 granted November 6, 1973 to Baier.

The invention is embodied in a pneumatic testing apparatus for cigarettes or analogous rod-shaped articles of the tobacco processing industry wherein spaced-apart first and second end faces of the articles flank a peripheral surface, normally the external surface of a tubular wrapper. The apparatus comprises a conveyor having article receiving means serving to transport a succession of articles in a predetermined direction and along a predetermined path so that the articles extend transversely of such direction and of such path, and means for testing each article in turn in a predetermined portion of the path.The testing means includes at least one first sealing device having means for abutting against the first end face of an article on the conveyor not later than in the predetermined portion of the path to thereby at least substantially seal the interior of a satisfactory article at the first end face of such article from the surrounding atmosphere, at least one second sealing device having means for sealingly surrounding the peripheral surface of an article on the conveyor in the region of the second end face of such article and to thereby at least substantially seal the interior of a satisfactory article in the region of such second end face from the surrounding atmosphere not later than on arrival of the article into the predetermined portion of the path, at least one opening provided in at least one of the associated first and second sealing devices in register with the respective end face of the article between the first and second sealing devices, and means for establishing a pressure differential between the interior and exterior of articles in the predetermined portion of the path by way of the opening in the one sealing device.

The arrangement is preferably such that the apparatus further comprises means for supplying to the conveyor articles in such orientation that the second sealing device sealingly engages that end portion of the article on the conveyor which is destined to be inserted into the mouth of the smoker, i.e., the filter plug if the article is a filter cigarette, cigar or cigarillo.

The pressure differential establishing means can comprise a source of compressed air or another suitable gaseous testing fluid and means for admitting testing fluid from the source into the article in the predetermined portion of the path by way of the opening or openings in the one sealing device. In such apparatus, each sealing device can have one or more openings in register with the respective end face of the article so that compressed testing fluid can flow into both ends of the article not later than in the predetermined portion of the path. The apparatus preferably further comprises a pressure gauge, a transducer or any other suitable means for monitoring the pressure differential between the interior and the exterior of each article in the predetermined portion of the path.

It is preferred to construct the testing means in such a way that it comprises a first annulus of discrete first sealing devices and a second annulus of discrete second sealing devices. Each sealing device of the first annulus is in register with a sealing device of the second annul us.

The abutting means of each first sealing device is preferably made, at least in part, of an elastically deformable material. This preferably also applies for the means for sealingly surrounding which forms or form part of the second sealing device or devices.

The conveyor is or can be a rotatory conveyor which defines an endless path, and the receiving means of the conveyor preferably comprises axially parallel flutes provided at the periphery of the conveyor and means for attracting articles to the flutes by suction.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved testing apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusual ofthefollowing detailed description of certain specific embodiments with reference to the accompanying drawing.

The single Figure of the drawing is a somewhat schematic fragmentary axial sectional view of a testing apparatus which embodies one form of the present invention and employs a rotary conveyor with an annulus of article receiving flutes for rodshaped articles of the tobacco processing industry.

The apparatus which is shown in the drawing is designed for the testing of rod-shaped articles of the tobacco processing industry, such as filter cigarettes 3 each having a filter plug 46 with an annulus of ventilating perforations 44 for admission of cool atmospheric air into the column of tobacco smoke, a plain cigarette (tobacco-containing portion) 47, a first end face 47a which is the free end face of the plain cigarette 47, and a second end face 46a which is the free end face of the filter plug 46.The filter cigarette 3 which is shown by broken lines in the upper portion of the drawing comprises a filler consisting partly of tobacco and partly offilter material, and a composite wrapper including the wrapper of the plain cigarette 47 and a uniting band which surrounds the wrapper of the filter plug 46 and sealingly connects the filter plug to the plain cigarette.

The testing apparatus comprises a rotatable drumshaped conveyor 1 with axially parallel peripheral receiving means in the form of flutes 2 machined into circumferentially extending ribs 2a on the body of the conveyor. The conveyor 1 is installed in a filter tipping machine, e.g., a machine known as MAX and shown schematically in commonly owned U.S. Pat.

No.3,948,084 granted April 6, 1976 to Heitmann et al.

The testing operation takes place prior to delivery of freshly manufactured filter cigarettes to storage or directly to a packing machine. The testing involves detection of all kinds of defects in the wrappers, such as excessive or insufficient permeability of the climatic zone including the perforations 44 in the wrapper of the filter plug 46, open seams, leakage in the region between the filter plug 46 and the plain cigarette 47, holes in the wrapper anywhere between the axial ends, frayed ends of the wrappers, inclination of the end faces 46a, 47a at an angle other than 90 degrees with reference to the axis of the cigarette 3 and/or a combination of such and/or other conceivable defects.

The filter cigarettes 3 are delivered into the flutes 2 in such orientation that they extend at right angles to the direction of their movement along the endless path which is defined by the conveyor 1, and the means for supplying a succession of such articles to the conveyor 1 comprises a suitable conveyor (note the conveyor 28 in Figure 1 of the aforementioned U.S. Pat. No. 3,948,084 to Heitmann et al.) which can receive articles from a turn-around device or from a device which halves filter cigarettes of double unit length in a manner not forming part of the present invention. The disclosure of the patent of Heitmann et al. as well as of each other patent and/or patent application listed herein is incorporated by reference.

The flutes 2 communicate with the intake ends of suction ports 6 which are machined into and extend substantially radially of the body of the conveyor 1 and communicate, during certain stages of orbital movement about the axis of the conveyor 1, with a suction channel 4 machined into a fixed hollow shaft 7. The suction generating device (e.g., a fan) which is connected to the shaft 7 is not shown in the drawing.

The shaft 7 surrounds a drive shaft 9 which is journalled therein in one or more antifriction bearings 8 and is attached to the body of the conveyor 1 by an annular connector 11 and screws 12 or analogous fasteners. The shaft 7 is coaxial and aligned with a stationary sleeve 14 which is affixed to the frame of the filter tipping machine by one or more levers or links 13. The drive shaft 9 extends into the interior of the sleeve 14 and rotates therein in additional antifriction bearings 8.

Afirst annular bearing support 17 surrounds the shaft 7 at one axial end of the conveyor 1 and is held against rotation by a key 16 in such a way that it can be shifted in the axial direction of the shaft 7. A second annular bearing support 17, which is or can be a mirror image of the bearing support 17 on the shaft 7, is mounted on the fixed sleeve 14 adjacent to the other axial end of the conveyor 1. The two bearing supports 17 have mirror symmetrical annular seats 18 for discrete antifriction bearings 19 whose axes are slightly inclined with reference to the axis of the conveyor 1. The outer races of the bearings 19supportand rotate with annular carriers 21 whose axes are also inclined with reference to the axis of the conveyor 1.The carriers 21 are mirror symmetrical to one another with reference to a plane which is normal to the axis of the conveyor 1 and is located between the two bearings 19. The arrangement is such that successive portions of the carriers 21 move toward each other while orbiting to positions at a level above the axis of the conveyor 1 and that successive portions of such carriers move away from one another while orbiting toward their lowermost positions, as viewed in the drawing. The carriers 21 can be said to resemble or to move not unlike wobble plates. The inclination of the left-hand carrier 21 is the same as that of the right-hand carrier 21 except that the two carriers are inclined in opposite directions.

The carriers 21 are inwardly adjacent to two stationary valve plates 22 which are connected to the respective bearing supports 17 bylinks or arms 23 and have smooth surfaces 24 in sealing engagement with the adjacent outer sides of the respective carriers 21. The valve plates 22, the carriers 21 and the antifriction bearings 19 are adjustable with the respective bearing supports 17 axially of the shaft 7 and sleeve 14 in order to convert the apparatus for the testing of shorter or longer filter cigarettes.

Means can be provided for effecting precise axial adjustments of the bearing supports 17 relative to the shaft 7 and sleeve 14, and screws or bolts or other suitable locking means are provided to hold the supports 17 in selected axial positions. The keys 16 prevent rotation ofthesupports 17 about the common axis of the shaft 7 and sleeve 14.

The right-hand carrier 21 supports an annulus of equidistant sealing devices 26' each of which has an elastically deformable sealing element 27' which includes a membrane 43' with a centrally located opening 43a' for the passage of testing fluid, normally air. The membranes 43' engage the end faces 47a of the respective plain cigarettes 47 and are designed to at least substantially seal the interior of the cigarettes 47 from the surrounding atmosphere while the respective filter cigarettes 3 are located in a predetermined portion of their path on the conveyor 1, namely, at a testing station which is disposed between two relatively short arcuate grooves 33 machined into the surfaces 24 of the respective valve plates 22.Successive sealing devices 26' which arrive at the testing station between the grooves 33 receive compressed gaseous testing fluid from a source 60 by way of a regulating or combined shutoff and regulating valve 42, a flow restrictor 41, a tee 31 a, a flow restrictor 31 b, a nipple 31 which is anchored in the respective valve plate 22, a channel 29 in such valve plate, the respective groove 33, one of several axially parallel bores 32 in the corresponding carrier 21, the nozzle 28' of the respective sealing device 26' and the opening 43a' of the respective membrane 43'. the length of each groove 33, as considered in the circumferential direction of the conveyor 1, is less than the distance between the axes of two neighboring sealing devices 26 or 26' so that the intervals of admission of testing fluid into the ends of the filter cigarettes 3 at the testing station are short or very short, especially in a modern filter tipping machine which can turn out many thousands of filter cigarettes per minute. The carriers 21 rotate relative to the respective valve plates 22 so that successive bores 32 in such carriers communicate with and move along the respective grooves 33 when the testing apparatus is in actual use.

Each membrane 43' forms an integral part of the respective elastically deformable tubular sealing element 27' which is attached to the respective nozzle 28'. Each element 27' can be made of natural rubber or an elastomeric synthetic plastic material.

The sealing devices 26 are designed to engage the filter plugs 46 of the respective filter cigarettes 3 and each thereof is constructed in such a way that its elastically deformable cupped sealing element 27 engages the peripheral surface immediately adjacent to the respective end face 46a of the cigarette 3.

Each deformable sealing element 27 is mounted on the respective nozzle 28 and has an opening 43a which is in register with the respective end face 46a.

Successive sealing devices 26 receive compressed testing fluid from a conduit 38, which contains the flow restrictor 41, by way of a further flow restrictor 31 c, the left-hand nipple 31, the channel 29 in the corresponding valve plate 22, the corresponding groove 33, and the corresponding bore 32 of the respective carrier 21. Sealing devices which are somewhat similar to the illustrated sealing device 26 are disclosed, for example, in the aforementioned German Offenlegungsschriften Nos. 42 962 and 31 812. Sealing devices which are similar to the illustrated sealing device 26' are disclosed in the aforementioned U.S. Pat.No. 3,948,084 as well as in German Offenlegungsschriften Nos. 23 24055 and 2444708. The material of each of the sealing elements 27, 27' is preferably soft and readily deformable so that it can conform to the shape of the adjacent portion of the respective filter cigarette 3.

The carriers 21 are connected to the conveyor 1 by bolts 34 each of which is anchored in the respective carrier and extends, with radial clearance, into a recess 36 in the respective end face of the conveyor 1 so that the carriers 21 share all angular movements of but can wobble relative to the conveyor 1. Tension springs 37 are provided to bias the carriers 21 away from the conveyor 1, i.e., into sealing engagement with the surfaces 24 of the respective valve plates 22.

The tension springs 37 store additional energy when they assume the positions which are shown in the drawing and dissipate some energy during movement away from the testing station between the stationary grooves 33.

The conduit 38 further contains a pressure gauge 39 which indicates the rise of pressure in the tested cigarette 3 while the latter is located at the testing station. As a rule, the gauge 39 will be provided in addition to or will be replaced with a transducer which is capable of generating signals denoting the condition of tested articles, and such signals are used to effect segregation (expulsion) of unsatisfactory cigarettes, e.g., in a manner as disclosed in commonly owned U.S. Pat. No. 4,154,090 granted May 1979 to Heitmann etal.

The flow restrictors are or can be of the adjustable type so as to enable the attendants accurately select the rate of flow of testing fluid into the ends of the cigarette 3 at the testing station between the grooves 33 of the two fixed valve plates 22.

The mode of operation of the testing apparatus is as follows: The prime mover (not shown) of the filter tipping machine rotates the shaft 9 which drives the conveyor 1 by way of the annular connector 11 and fasteners 12 so that the RPM of the conveyor matches that of the shaft 9. The channel 4 in the stationary shaft7 is connected to the suction gener- ating device so that the ports 6 draw air from those flutes 2 which contain filter cigarettes 3, i.e., from the flutes which travel between the cigarette supplying conveyor and the conveyor serving to receive tested cigarettes from the conveyor 1.This ensures that the filter cigarettes 3 remain on the conveyor 1 during travel toward, through and beyond the testing station between the stationary grooves 33, i.e., toward, through and beyond that predetermined portion of the path for cigarettes wherein the cigarettes are tested for the integrity of their wrappers. The article supplying conveyor delivers filter cigarettes 3 to be tested into those flutes which are disposed exactly or substantially diametrically oppo site the testing station, i.e., into the flutes which are disposed between the carrier portions and pairs of registering testing devices 26, 26' at a maximum distance from one another. The carriers 21 rotate with the conveyor 1 and shaft 9 due to the provision of bolts 34.Each filter cigarette 3 is inserted into the respective flute 2 in such a way that its two end faces are spaced apart from the respective membrane 27a' and cupped sealing element 27. As the conveyor 1 continues to rotate, the mutually inclined seats 18 of the annular bearing supports 17 cause the sealing devices 26,26' to move nearer to each other and toward the respective end portions of the cigarette 3 therebetween. Thus, the membrane 43' moves against the end face 47a of the respective plain cigarette 47 and the end face 43 around the opening 43a moves into abutment with the end face 46a of the respective filter plug 46 whereby the sealing element 27 sealingly engages the peripheral surface of the wrapper of the respective filter cigarette 3 in the region of the end face 46a.Therefore, both ends of the interior of a satisfactory filter cigarette 3 are adequately sealed from the surrounding atmosphere not later than when the cigarette moves into the space between the grooves 33 of the stationary valve plates 22.

Since the cigarette 3 which approaches the testing station is engaged by the internal annular surface of the sealing element 27, eventual unevennesses in the marginal portion ofthe wrapper in the region of the sealing device 26 cannot adversely influence the testing operation, i.e., the seal between the interior of the filter plug 46 and the surrounding atmosphere is satisfactory even if the end face of the filter plug and/or the wrapper of the filter plug in the region of such end face is not perfect. Unevennesses at the free end of the filter plug 46 can develop as a result of cutting the filter rod with a dull knife so that the cutting operation results in the development of notches, frayed ends or analogous defects which may detract somewhat from the appearance of the filter plug but not sufficiently to warrant segregation of the respective filter cigarette 3 as a reject. In other words, the annular sealing element 27 ensures that eventual departure of the left-hand end portion of the wrapper of the cigarette 3 which is shown in the drawing from perfect or ideal condition cannot adversely influence the testing operation by causing a pronounced distortion of the result of testing of the pressure differential between the interior and the exterior of such wrapper. Thus, the illustrated testing apparatus is evidently capable of preventing segregation of filter cigarettes whose filter plugs may need not be exactly perfect but are still passable to the manufacturer and to the purchaser.

As the same time, the membrane 43' seals the other end face of the filter cigarette 3 at the testing station by bearing against such end face with a force which suffices to adequately seal the interior of the plain cigarette 47 from the surrounding atmosphere.

If the free end portion of the wrapper of the plain cigarette 47 is sufficiently frayed to warrant ejection of the respective filter cigarette, the membrane 43' will permit flow of compressed testing fluid from the respective bore 28' into the plain cigarette 47 and thence into the atmosphere along the exposed side of the membrane 43' so that the aforementioned transducer detects the absence of requisite pressure differential and generates a signal which results in segregation of the respective filter cigarette 3 from remaining (satisfactory) cigarettes.

It will be seen that the illustrated testing apparatus is designed to invariably detect filter cigarettes which are defective at their tobacco-containing ends but does not identify or label as defective each cigarette whose filter end is not exactly or absolutely perfect.

When the two ends of a cigarette 3 at the testing station are properly engaged by the respective sealing elements 27, 27', the corresponding bores 32 of the respective portions of the carriers 21 move into register with the adjacent grooves 33 so that the testing operation begins because the grooves 33 are in permanent communication with the source 60 of compressed testing fluid to the extent which is determined by the setting of the valve 42 and/or various flow restrictors in the conduit 38. In a modern filtertipping machine, the interval of testing (i.e., the interval of communication between the interior of the wrapper of a cigarette 3 and the conduit 38) is normally in the range of a few milliseconds.The gauge 39 (but normally a suitable transducer) can detect all types of flaws, i.e., not only defective ends of the wrappers but also the presence of partially or fully open seams, holes in the median portion of the wrappers, absence of adequate seals in the regions where the filter plugs are connected to the respective plain cigarettes and/or a combination of two or more such defects. Moreover, the transducer can detect whether the rate of admission of cool atmospheric air via perforations 44 is excessive or insufficient.

As the freshly tested filter cigarette advances beyond the testing station, the corresponding portions of the carriers 21 (and hence the corresponding sealing devices 26,26') move away from one another, as considered in the axial direction of the conveyor 1, so that the tested cigarette can be transferred onto a receiving conveyor at a time when its end faces are disengaged from the corresponding sealing elements 27 and 27'. Suction in the corresponding ports 6 is interrupted not later than when the tested cigarette 3 reaches the receiving conveyor to thus allow for convenient and unimpeded transfer of the cigarette from the respective flutes 2. As a rule, a tested cigarette which is about to be removed from its flutes 2 is totally or practically totally disengaged from the corresponding (registering) sealing elements 27 and 27'.

All defective cigarettes are segregated from satisfactory or acceptable cigarettes, either on the testing conveyor 1 or on a next-following conveyor, e.g., by resort to a pneumatic ejector which directs a blast of compressed gas (e.g., air) against the defective cigarette at the exact moment when such cigarette enters the range of its nozzle. Ejection signals are generated when the monitored pressure differential is outside of a predetermined range of acceptable values.

An important advantage of the improved testing apparatus is its selectivity, i.e., the apparatus can discriminate between the two ends of each tested article to disregard certain imperfections at the end which is to be inserted into the mouth but to be much more accurate (insofar as the detection of defects is concerned) at the tobacco-containing end, i.e., at that end which is remote from the mouth when the cigarette is being smoked. The just discussed advantage is attained by resorting to relatively simple and inexpensive means, i.e., by resorting to two annuli of different sealing devices wherein the sealing devices of one annulus can sealingly engage the wrapper (peripheral surface) in the region of one end and the sealing devices of the other annulus can sealingly engage the adjacent end faces of the articles to be tested.The improved apparatus has been found to be highly reliable and it can be readily adjusted (via valve 42 and/or various flow restrictors and/or by moving the carriers 21 nearer to or further away from one another and/or by selecting softer or less deformable sealing elements 27,27') so as to ensure predictable and reliable segregation of cigarettes which exhibit certain types of defects and/or defects of certain severity.

Quite surprisingly, the quality of the testing operation (by resorting to the improved apparatus) is much more satisfactory than the quality of testing with conventional apparatus wherein the sealing elements which engage successive cigarettes at one end are identical with the sealing elements for the other ends of the cigarettes. Thus, the improved apparatus can discriminate between the sealing operations at the two ends of each article to be tested and is thus capable of greatly reducing the number of ejected satisfactory articles as well as the number of non-ejected or non-detected unsatisfactory articles. The invention is based, in part, on the recognition that some minor defects (especially insofar as the appearance is concerned) at the filter ends are much less important, and hence more readily acceptable, than even relatively minor defects at those ends of the articles which are remote from the mouth during smoking.

Claims (11)

1. In an apparatus for pneumaticallytesting cigarettes and analogous rod-shaped articles of the type having first and second end faces and a peripheral surface extending between the end faces, the combination of a conveyor having article receiving means arranged to transport a succession of articles in a predetermined direction and along a predetermined path so that the articles extend transversely of such path; and means for testing each article in turn in a predetermined portion of said path, including at least one first sealing device having means for abutting against the first end face of an article on said conveyor not later than in said predetermined portion and to thereby at least substantially seal the interior of a satisfactory article at the first end face thereof from the surrounding atmosphere, at least one second sealing device having means for sealingly surrounding the peripheral surface of an article on said conveyor in the region of the second end face of such article and to thereby at least substantially seal the interior of a satisfactory article in the region of such second end face from the surrounding atmosphere not later than on arrival of the article into said predetermined portion, at least one of said sealing devices having at least one opening in register with the respective end face of the article which is being engaged thereby, and means for establishing a pressure differential between the interior and the exterior of articles in said predetermined portion by way of the opening in the one sealing device.

2. The combination of claim 1,wherein said pressure differential establishing means comprises a source of pressurized testing fluid and means for admitting testing fluid from said source into the article in said predetermined portion by way of the opening in the one sealing device.

3. The combination of claim 1,furthercompris- ing means for monitoring the pressure differential between the interior and the exterior of each article in turn in the predetermined portion of said path.

4. The combination of claim 1 for testing rodshaped articles of the type wherein each article has a first end portion arranged to be held in the mouth of a smoker and a second end portion which is to be lighted for the purpose of smoking, and further comprising means for supplying articles to said conveyor in such orientation that the first end portions of the articles are engaged by said second testing device.

5. The combination of claim 1 for testing rodshaped articles of the type comprising a filter at one end thereof, further comprising means for supplying articles to said conveyor in such orientation that the filters of the articles are engaged by said second sealing device.

6. The combination of claim 1,wherein said testing means comprises a first annulus of discrete first sealing devices and a second annulus of discrete second sealing devices, each sealing device of said first annulus being in register with a sealing device of said second annulus.

7. The combination of claim 1, wherein said abutting means is elastically deformable.

8. The combination of claim 1, wherein said means for sealingly surrounding is elastically deformable.

9. The combination of claim 1, wherein said conveyor is a rotatory conveyor and said path is an endless path.

10. The combination of claim 9, wherein said receiving means comprises axially parallel flutes provided at the periphery of said conveyor and means for attracting articles to said flutes by suction.

11. Apparatus for pneumatically testing cigarettes and analogous rod-shaped articles, substantially as herein described with reference to the accompanying drawings.