Machine for manufacturing pouches containing a tobacco mixture

In a machine (1) for manufacturing pouches (2) filled with portions (36) of a tobacco mixture, comprising a rotating drum (8) on which a continuous stream (5) of the mixture is formed and conveyed to a station (13) where the portions (36) are divided from the stream, and where the portions (36) are transferred by a pneumatic ejection and feed system (21) to a wrapping station (7), moisturizing substances are added to the mixture by a dispensing system (22) associated with the ejection and feed system (21).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of International Application PCT/IB2008/002768 filed Oct. 9, 2008 which designated the U.S. and that International Application was published under PCT Article 21(2) in English.

This application claims priority to Italian Patent Application No. B02007A000688 filed Oct. 12, 2007, and PCT Application No. PCT/IB2008/002768 filed Oct. 9, 2008, which applications are incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to a machine for manufacturing pouches containing a tobacco mixture, in particular for oral use (a product also known by the name of snus).

Besides tobacco, such mixtures typically contain oily substances serving as moisturizers (honey or molasses), and essences of flowers or fruit as aromatic agents.

BACKGROUND ART

As regards the production of snus pouches, the prior art embraces a machine comprising a hopper filled with the tobacco mixture, and rotary conveyor means to which the mixture is released from an outlet of the hopper.

Rotary conveyor means consist in a disc centred on a vertical axis and furnished with peripheral cavities, each containing a portion of tobacco mixture corresponding to the contents of a single pouch.

The single portions are carried by the disc toward an exit or transfer station where they are ejected and thereupon directed along a rectilinear feed duct to a wrapping station; here, the portions of tobacco mixture are packaged in respective pouches.

Alternatively, the conveyor means can take the form of a drum rotatable intermittently about a horizontal axis, on which a continuous stream of tobacco mixture is formed and transported to an exit or transfer station where segments of the stream, corresponding to single portions, are directed into and along the aforementioned rectilinear feed duct to the wrapping station where they are packaged in respective pouches.

The outer surface of the rotating drum presents an annular groove, connected to suction means and accommodating the continuous stream, which is released at the aforementioned transfer station segment by successive segment, each corresponding to a single portion.

In both of the cases described, the transfer of the mixture at the relative station is brought about by pneumatic ejection means, which operate by producing a jet of air such as will distance the portions singly and in succession and feed them along the rectilinear duct.

The duct comprises a funnelform mouth and a rectilinear cylindrical portion.

The wrapping station comprises a tubular mandrel, placed at the outlet end of the rectilinear cylindrical portion, over which a continuous web of wrapping material is formed into a tubular envelope such as can be sealed longitudinally and transversely and then cut, all by conventional methods, so as to obtain a continuous succession of pouches containing the aforementioned portions of tobacco mixture.

It has been found that mixtures adopted for tobacco products of the type in question, by reason of their particular composition, tend to stick and solidify on the various processing and conveying elements of the machine, with the result that frequent servicing is required.

This is a drawback that can bring the machine ultimately to a standstill, and occurs in particular at the restriction presented by the funnelform mouth of the feed duct.

The likelihood of clogging in the duct is increased by the action of the aforementioned pneumatic ejection means, which has the effect of reducing the moisture content of the mixture and causing deposits of the material to dry and harden, so that cleaning operations are made more difficult.

DISCLOSURE OF THE INVENTION

The object of the present invention, accordingly, is to overcome the drawbacks described above.

With reference toFIGS. 1 and 2, numeral1denotes a machine used in the manufacture of pouches2containing a tobacco mixture for oral use.

The machine1comprises a hopper3serving as means of storing and feeding the tobacco mixture, connected by way of conveyor means4on which to form a continuous stream5of the mixture, and by a rectilinear duct6, to a wrapping station7where the pouches2are fashioned.

More exactly, such conveyor means4comprise a drum8rotatable about a horizontal axis9, presenting a cylindrical wall10and enclosed by two mutually opposed side walls11(one only of which is visible inFIG. 1).

The drum8rotates intermittently about the axis9in an anticlockwise direction, as viewed in the drawings, through steps of predetermined angular distance, and is interposed between a bottom outlet end12of the hopper3and a portioning or transfer station13positioned substantially at 270° from an infeed station coinciding with the hopper outlet.

The cylindrical wall10of the drum8presents an annular groove14of predetermined width, pierced along its entire circumferential length by through holes15communicating with an internal annular chamber divided into a first sector16and a second sector17.

The second sector17, which extends through an arc of predetermined width, is sandwiched between the two ends of the first sector16and positioned to coincide with the transfer station13.

The first sector16is connected by way of a duct18to a source of negative pressure indicated schematically as a block, denoted19.

The second sector17in turn is connected via a further duct20to pneumatic ejection and feed means21, by which segments of the stream5are separated from the drum, and to dispensing means denoted22in their entirety, from which moisturizing substances are delivered.

The rectilinear feed duct6comprises an inlet portion or mouth23of funnelform appearance, facing the sector of the drum coinciding with the transfer station13, and a tubular body24.

Numeral25denotes a tubular mandrel, connected to and aligned coaxially with the outlet of the tubular body24, around which a tubular envelope26of paper wrapping material27(decoiling from a roll, not illustrated) is fashioned through the agency of conventional folding means (not illustrated).

The tubular envelope26is sealed longitudinally by first sealing means28operating in close proximity to the tubular mandrel25.

The envelope26is also sealed transversely by second sealing means29operating downstream of the tubular mandrel25.

As illustrated inFIG. 2, the pneumatic ejection and feed means21are composed of a pump30, generating an intermittent flow of air delivered by the aforementioned means22from which moisturizing substances are dispensed; such means22comprise a mixing chamber31provided with an air inlet32, and a further inlet connected to the outlet duct33of a reservoir34containing vaporized water or other moisturizing substances. Also forming part of the dispensing means22is a control unit35, connected to the mixing chamber31, which serves to regulate the level of moisture in the flow generated by the pump30according to the type of material making up the tobacco mixture and/or the operating speed of the machine1.

In operation, with the drum8rotating intermittently, tobacco mixture is collected and formed gradually into a continuous stream5within the aspirating annular groove14.

The continuous stream5advances into the transfer station13where, with each step indexed by the drum8, a jet of compressed air moisturized with the substances delivered by the dispensing means22is expelled from the second sector17through the relative holes15, causing a segment of the stream5to be ejected from the groove and directed through the funnelform mouth23into the tubular body24of the rectilinear feed duct6. The ejected segment is of predetermined length corresponding to a single wrappable portion36.

Emerging from the rectilinear duct6, the portion36of tobacco mixture passes along the tubular mandrel25, around which the aforementioned tubular envelope26of wrapping material is fashioned progressively by a conventional forming method.

The tubular envelope26is closed up longitudinally by the first sealing means28.

On leaving the tubular mandrel25, the tubular envelope26containing the successive portions36of tobacco mixture is engaged transversely by the second sealing means29, operating intermittently and timed to match the frequency with which the portions36are ejected, in such a way that each portion will be enclosed between two successive transverse seals.

As a result of these operations, a continuous succession of tobacco-filled pouches2will emerge, connected one to the next by way of the transverse seals. Downstream of the transverse sealing means29, the single pouches2are separated one from the next by cutting means37.

The addition of a moisturizing substance eases the passage of the portions36of tobacco mixture along the rectilinear duct6, preventing the formation of deposits and the risk of clogging, especially at the restriction presented by the funnelform mouth23.

As illustrated in the example ofFIG. 3, the moisturizing substance can be also be added directly to the tobacco mixture inside the funnelform mouth of the rectilinear duct6, either as well as or instead of being entrained in the air jet as described above.

In this instance the funnelform mouth, denoted23′, is fashioned from a porous material and housed within an annular chamber38connected by way of a duct39to the pump30, or to other means22′ of dispensing the moisturizing substance.

In the example ofFIG. 4, the machine is equipped with a vibrator device40connected to the funnelform mouth23of the feed duct.

The action of this device, combined with that of the moisturizing substance, is particularly effective in ensuring that deposits of the tobacco mixture do not form at the entry point of the rectilinear feed duct6.

With reference to the embodiment illustrated inFIGS. 5 and 6, the funnelform mouth23is covered both internally and externally by a tubular element or sheath41of elastic material, secured by a first end to an external face presented by the inlet end of the tubular body24, looped over the inlet rim of the mouth23, and secured by the second end to an internal face presented by the inlet end of the tubular body24.

The space delimited between the sheath41and the flared surfaces of the mouth23is connected to a source of pulsed compressed air, denoted42, of which the action produces a vibratory effect on the mouth23of the rectilinear feed duct6similar to that of the device described previously.