This invention relates to a machine for making tobacco industry products.

It should be noted that the term "tobacco industry products" is used to denote, for example, cigarettes, filter-tipped cigarettes, cigarette filters of any kind, in particular, filters composed of two or more segments, cigarette packets, whether hard or soft, cigarette packages and other products similar to these.

Figure 1 schematically illustrates in its entirety a prior art making machine, denoted by the numeral 100, comprising a base having a vertical wall which supports a plurality of operating elements 101.

The operating elements 101 are, for the most part, rotary drums which revolve about horizontal axes of rotation and which are mounted on the vertical supporting wall.

More specifically, the rotary drums are provided with a plurality of suction cavities for receiving and withholding the tobacco products during processing.

Every making machine 100 also comprises an air suction system 103 for the rotary drums and designed to generate a predetermined negative pressure at the respective suction cavities.

The suction system 103 of prior art making machines 100 comprises an air suction source 102 and a main manifold 105 extending along the machine 100 and in fluid communication with the source 102.

The rotary drums 101 are connected to respective compartments 104 formed internally of the base and connected to the main manifold 105 through flow openings 106.

More specifically, the compartments 104 are delimited by the vertical wall supporting the rotary drums 101 and by internal partition sectors, defining large spaces within the base, as illustrated in Figure 2. In use, the air suction source 102 generates a predetermined negative pressure inside the main manifold 105 and, through the flow openings 106, inside each of the compartments 104, so that the rotary drums 101 connected to the compartments 104 are subject to the negative pressure generated inside the selfsame compartments 104. A similar solution is also known, for example, from DE10200806031.

The suction system 103 described above is referred to technically as a "comb system" in that it has a main section, that is, the main manifold 105, which branches into successive use locations, that is, the compartments 104.

This constructional solution is not free of disadvantages, however.

In effect, in the suction system 103, the distribution of the air suction flow rates is not uniform since the air suction flow tends to be weaker at the use locations or compartments 104 which are furthest away from the source 102.

Also, when some use locations are in need of a boost in the air suction flow rate, the source 102 increases the air flow rate in the entire system, even where not needed.

Further, the suction system 103 is inefficient in terms of energy consumption and not reactive in responding to transients in that it is slow to restore normal operating conditions since emptying out the compartments 104 takes a long time and a lot of energy from the source 102.

Moreover, turbulence may be created inside the compartments 104 which reduces the efficiency of the suction system 103.

This invention has for an aim to provide a machine for making tobacco products which overcomes the above mentioned disadvantages.

More specifically, the aim of this invention is to provide a machine for making tobacco products which comprises a suction system which allows uniform distribution of air suction flow rates to the use locations and which reacts quickly to transients and restores the machine to normal operating conditions.

The technical purpose indicated and the aims specified are achieved by a machine for making tobacco industry products comprising the technical features set out in the independent claims 1 and 2.

The invention is described below with reference to the accompanying drawings, which illustrate a non-limiting embodiment of it, and in which:

• Figure 1 is a schematic front view of a prior art machine for making tobacco industry products;
• Figure 2 is a perspective view of a detail from Figure 1;
• Figure 3 is a perspective view of a suction system of a machine for making tobacco industry products according to this invention;
• Figure 4 is schematic front view of the suction system of Figure 3.

With reference to Figures 3 and 4, the numeral 1 schematically indicates a machine for making tobacco industry products which comprises a base 2 having a vertical front wall 3 and a vertical rear wall 9 facing the vertical front wall 3.

The making machine 1 comprises a plurality of operating elements 4 supported by the vertical front wall 3.

The operating elements 4 are rotary drums 5, each revolving about a respective axis of rotation which is substantially horizontal relative to the vertical wall 3.

The machine 1 comprises an air suction system 6 comprising at least one suction source 7. More specifically, the source 7 generates a predetermined negative pressure as a function of the working conditions of the operating elements 4.

Preferably, the suction system 6 comprises a single source 7 capable of serving the entire system 6.

More specifically, the suction system 6 comprises a tubular structure 8 which connects the source 7 directly to the operating elements 4.

Unlike the prior art, the tubular structure 8 of the suction system 6 is defined by a plurality of conduits 10,14 which branch off from the source 7 towards the operating elements 4 placing the latter in direct fluid communication with the source 7 itself.

The tubular structure 8 allows the space occupied by the suction system 6 in the base 2 to be significantly reduced since the large empty spaces constituted by the aforementioned compartments are no longer necessary.

Preferably, the conduits 10,14 of the tubular structure 8 have a substantially rectangular cross section.

Advantageously, tubular structure 8 means a structure made as a single component designed to be installed inside the base 2 of the machine 1.

More specifically, again by way of example, the single component is interposed between the vertical front wall 3 and the vertical rear wall 9.

The tubular structure 8 is ring-shaped and is formed by a main conduit 10 having two inlet openings 11 in communication with the source 7.

The tubular structure 8 comprises a main ring 12 and at least one secondary ring 13. In the embodiment described, there are four secondary rings 13.

The main ring 12 is formed by the main conduit 10 and each secondary ring 13 is formed by at least one secondary conduit 14 extending from the source 7 and in fluid communication with the main conduit 10.

Each secondary ring 13 is thus formed by at least one secondary conduit 14 and by at least part of the main conduit 10.

More specifically, each secondary conduit 14 has an inlet opening 15 in communication with the source 7 and a connecting opening 16 in communication with the main conduit 10. Consequently, the secondary conduits 14 of each secondary ring 13 are connected to the main conduit 10.

That means the secondary conduits 14 of the tubular structure 8 also place the main conduit 10 in direct communication with the source 7 through the connecting openings 16.

The configuration of the tubular structure 8 is defined both by the main conduit 10 and by the arrangement of the secondary conduits 14. More specifically, the main ring 12 and each secondary ring 13 have a substantially polygonal shape having, at their vertices, rounded conduit stretches 17 and, along their sides, straight conduit stretches 18.

This configuration is substantially dependent on the arrangement of the operating elements 4 on the vertical front wall 3 of the machine 1, in order for the operating elements 4 to be connected directly to the source 7.

In order to place the operating elements 4 in fluid communication with the source 7, the tubular structure 8 comprises a plurality of branches 19 connecting the operating elements 4.

More specifically, at each branch 19, the tubular structure 8 has a corresponding fitting 19a for connecting the respective operating element 4.

More specifically, the main conduit 10 comprises a plurality of branches 19 disposed one after the other along the tubular structure 8, and each secondary conduit 14 comprises at least one branch 19. The branches 19 have respective outlet openings 20 at which they are connected directly to the operating elements 4 through the fittings 19a.

Preferably, the branches 19 are located along the straight conduit stretches 18 because they are not subject to the concentrated load losses which occur at the rounded conduit stretches 17.

In the embodiment described, each straight conduit stretch 18 of the main conduit 10 has at least two branches 19 and each straight conduit stretch 18 of the respective secondary conduit 14 has one or more branches 19.

The arrangement of the branches 19 and the configuration of the tubular structure 8 determine a path P along which the air drawn into conduits 10, 14 circulates.

As illustrated in Figure 4, the air circulating along the path P supplies each operating element 4 through at least two air flow routes formed by at least one secondary conduit 14 and at least part of the main conduit 10.

In other words, the source 7 is capable of generating a predetermined negative pressure in each operating element 4 by causing the air to flow in the main ring 12 and in the secondary rings 13 along the path P.

This is possible because the source 7 is simultaneously in communication with the two inlet openings 11 of the main conduit 10 and with the inlet openings 15 of the secondary conduits 14 connected to the main conduit 10 and, therefore, the air feeds the operating elements 4 by way of at least two flow routes.

In order to regulate the suction air flow generated by the source 7 and circulating in the tubular structure 8, the suction system 6 comprises flow regulator means 21 positioned along the tubular structure 8 itself. More specifically, the flow regulator means 21 are positioned both along the main conduit 10 and along the secondary conduits 14, in such a way as to regulate the flow of air drawn into the main ring 12 and into each secondary ring 13.

Advantageously, the ring shape of the tubular structure 8 of the suction system 6 makes it possible to equally divide the suction flow rates since, as stated above, each operating element 4 is in communication with the source 7 by way of at least two flow routes through the main conduit 10 and the secondary conduits 14. Moreover, the direct communication between the operating elements 4 and the source 7 greatly improves the reactivity of the suction system 6 to transients, that is to say, to conditions of non-equilibrium, allowing normal operating conditions to be restored in a short space of time.

In an alternative embodiment, the connecting conduits 10,14 of the tubular structure 8 are built into the base 2.

In a first embodiment, the machine 1 described above is a cigarette making machine, in particular a machine for making filter-tipped cigarettes.

In a different embodiment, the machine 1 described above is a machine for making cigarettes filters, in particular filters composed of two or more filtering segments.

In a further embodiment, the machine 1 described above is a packing machine for making cigarette packets or groups of cigarette packets.