BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a machine for the filling of containers, in particular for the filling of bottles and to the relative filling method. 
     2. Discussion of the Background 
     The bottling and the packaging industry in general performs a series of successive operations for the purpose of filling containers such as bottles, vials, and cans with foodstuffs, cosmetics, chemical and pharmaceutical products, oils and paints, glues, detergents and other materials. 
     In particular, the foodstuffs and wine industry usually include the preliminary washing, rinsing and sanitizing operations for the bottles to be filled. 
     Then, the filling operation may be performed in different ways, depending on the products destined to fill the containers; for the filling of gaseous and sparkling wines, for example, the filling machines in use are of a so-called isobaric type, because the pressure of the container is the same as that of the storage tank holding the wine to be filled. A balanced pressure is therefore established between the holding container and the bottles, while evacuating the inside air to the outside. A first phase is therefore performed by pre-evacuating the air contained in the bottles while aspirating the same with a vacuum pump from a small tube placed next to the neck of each bottle. 
     EP-A-597161, for example, dislcoses a known filling machine of the isobaric type according to the preamble of the invention. 
     Said known machine essentially consists of a horizontal cylindrical container, whose lower section mounts a series of particular filling taps. The wine level in the tank is regulated by a float which governs, as the level changes, the opening and closing of a vent opposite to the inert gas chamber above the wine, resulting in a constant liquid level. 
     The filling taps are generally composed of a spout with two concentric tubes, one originating in the lower section of the tank draining the wine to the bottle and one leading to the inert gas chamber to allow discharging the air contained in the bottle. 
     The air and wine tubes of each spout are actuated respectively by two controlling devices, each of which includes a small spring-loaded piston acting as a true shut-off tap. The pair of small pistons is actuated by the alternating motion of lever fitted with a handle, pressing its two elbows against a bracket which acts, in the lower part of the tap, on the actuating heads of the two small pistons. 
     The opening of the latter occurs at two separate instants: an air vent opens up first, allowing an instantaneous balancing of the pressure between the gas chamber and the interior of the still empty bottle, thus starting the flow of the wine filling the bottle. Other vacuum-filling machines are known for handling many types of foodstuffs, such as wines, liquors, sirups, fruit-juices, oils and liquid chemicals, shampoos, and cosmetic preparations. These machines work under a slight depression, thus creating a more or less pronounced vacuum in the container aspirating the product, which moves from the main source to the machine tank mounted above the filling section; the liquid volume in the tank is regulated by a float or by appropriate probes. 
     The containers are lifted toward the filling nozzles on cam-actuated tables and made to tightly fit against the rubber rings of the nozzles. The inside air is gradually expelled as the vacuum is applied; this achieves a substantial seal at the entrance tap, thus preventing any spillage in the surrounding environment; if a container is defective and cannot withstand the vacuum, it cannot be filled and is therefore automatically discarded. 
     Another type of traditional filling machine is the so-called volumetric or gravity machine, in which the filling occurs by free falling and constant dosing. The product is aspirated from the vat above the machine, immersed in the dosing devices and fed to the containers by the latter. 
     The machine is equipped with a number of dosing devices, each constituted by a cylinder with an internal piston aspirating the desired quantity of product, whose volume is determined by the diameter of the cylinder and the length of the piston run. 
     In the isobaric and in the known vacuum-actuated machines, however, the liquid to be bottled flowing through the neck of the bottle comes, while only for a brief period, in the contact with the air contained therein; moreover, the insufflated inert gas crossing the same conduit as the flowing liquid before falling into the bottle mixes with the liquid itself, thus causing some evident oxidising problems and therefore a rapid alteration of the same liquid. 
     In particular, these negative consequences are extremely important where edible goods with a short conservation span, such as wine, tea, milk and the like are bottled. In this regard and to eliminate this shortcoming, some isobaric machines have been developed which allow for a separate air return from the liquid handled, and can be equipped with a separate tubing for insufflating inert gas to the bottle. However, even the use of these machines cannot eliminate the problem of the presence of a certain volume of oxygen in the neck of the bottle, which remains in contact with the upper layer of the liquid contained therein. 
     In order to perform the phases of pre-evacuating the air inside the bottles and insufflating inert gas through the neck, it was further proposed to utilise a dedicated tube, fitted on the outside of the filling apparatus and separated from the central liquid feeding tube. 
     This solution, while advantageous from the viewpoint of an actual absence of product contamination and/or oxidation, poses numerous problems associated with the installation of the machine and the encumbering of relatively wide working spaces. 
     Moreover, an embodiment of this type amounts to production and operating costs that should rather be minimized. 
     The use of gravity machines avoids the oxidising problems mentioned above, because the pressure differential existing between the bottle interior and the filling tube is not used to introduce the liquid to the bottle, and the air aspirating step is therefore eliminated. However, these machines do not allow a complete filling process, because they make it impossible to perform the pre-evacuating and/or gas insufflating phases across the neck of the bottle; these operations must in fact, if desired, necessarily be carried out by dedicated systems, with the ensuing production delays and relatively high production costs. 
     SUMMARY OF THE INVENTION 
     The purpose of this invention is to achieve a machine for the filling of containers, in particular of bottles, capable of eliminating the mentioned shortcomings or to indicate a machine for the filling of bottles equipped with an effective seal at the entrance tap and simultaneously capable of preventing any air contact with the liquid to be bottled. 
     Another purpose of this invention is to achieve a machine for the filling of containers, in particular of bottles, which should also be capable of performing the phases of pre-evacuating the air inside the bottles and insufflating inert gas through the neck of the same, so as to maintain a stationary fluid condition above the free liquid level. 
     A further purpose of this invention is to indicate an effective method for the filling containers, in particular of bottles, to be carried out on the machine, in accordance with this invention. 
     A further purpose of the invention is to achieve a machine for the filling of bottles based on an easy and inexpensive construction, without a need to employ complex technologies or relatively costly components in relation to the advantages obtained. 
     According to the present invention, these purposes are attained by a machine for the filling of containers, in particular for the filling of bottles and the relative filling method, according to the claims  1  and  15 , respectively, to be referred to for brevity. 
     Advantageously, the machine of the present invention is in every respect constituted by a traditional machine operating at a slight depression, with all the resulting benefits, such as a perfect seal at the liquid dispensing tap, combined with the added advantages of a vacuum-operated machine, such as the low absorption of oxygen by the bottled liquid, and simultaneously with those typical of an isobaric machine. Moreover, the same machine is capable of performing the phases of pre-evacuating air from the bottles and insufflating inert gas through the necks of the same, in addition to the normal operations of filling and releasing the residual liquid. 
     This doubling-up of the phases within the same machine is achieved by utilizing a cam endowed with a continuously rotating motion and a particular profile, coupled with an actuating piston conferring it a variable motion. 
     An actuating piston transmits an alternating motion to the bottle moving in the direction of the filling path, toward the tap or opposite to it, depending on the machine operating system. 
     The profiled cam is further connected to a second cam commanding a valve, positioned above the filling section, which can be commuted to three different positions corresponding to the phases of insufflating inert gas into the bottle, operating under a slight depression and operating under a vacuum. 
     The latter case allows performing a forced filling step in the presence of a powerful vacuum in the bottle, so as to attain better performances from the viewpoint of production speed and filled product purity. 
     However, such an operation can be performed only if the handled fluid does not foam during the mixing stage. The forced filling of the containers can therefore be carried out by water, but not, for instance, if the filling must be done with wine. Further characteristics and advantages of a machine for the filling of containers, in particular of bottles and the relative method of filling in accordance with the present invention, will become more evident from the following description and from the accompanying schematic drawings which show a non limiting embodiment of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 schematically represents a partial sectional view of a traditional filling machine, of a type working under a slight depression or by gravity; 
     FIG. 2 schematically shows a partial sectional view of a traditional filling machine of a type working under a slight depression or by gravity, equipped with an returning tube for the air separated from the filling liquid; 
     FIG. 3 schematically represents a partial sectional view of a first embodiment of a machine for the filling of containers, in particular bottles, according to the present invention; 
     FIGS. 4 and 5 represent two enlarged details of the FIG. 3, respectively; 
     FIG. 6 represents the schematic geometric profile of a cam utilized in the machine shown in FIG. 3, according to the present invention; 
     FIG. 7 schematically represents a partial sectional view of a second embodiment of a machine for the filling of containers, in particular of bottles, according to the present invention; 
     FIGS. 8,  9  and  10  schematically represent three partial sectional views of further embodiments of a machine for the filling of containers, in particular of bottles, according to the present invention; 
     FIGS. from  11  to  21  schematically represent partial sectional views of a machine for the filling of containers, in particular of bottles, according to the present invention; in various phases of a filling process. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIGS. 1 and 2,  10  generally indicates the container in which the liquid is introduced, being drained from a nozzle  85  of a filling section  45  of a filling machine  100 ; in a preferred but non limiting embodiment of the present invention, the machine  100  is suitable for bottles  10  destined for foodstuffs, such as water, wine, tea, milk, sirups, fruit juices and the like. 
     The machine according to the invention can also advantageously be used for filling the bottles  10  with liquid products in general, even if not of the food type, provided they are free of gases. 
     The nozzle  85  is fitted at the lower end of a spout comprising two concentric tubes indicated by  30  and  35 , respectively, into which the liquid to be introduced to the container  10  and the air escaping from the container  10  to the outside flow in opposite directions. The air is aspirated from the container  10  by a vacuum pump schematically shown by  52 , connected by a tubing  50  and a fitting  51  to a chamber  60  of a reservoir  61  receiving the tube  35 . The tank  61  includes an area  55  for collecting liquid mounted opposite to the tube  30 , at a certain height  56 . 
     It should be noted that the path of the air aspirated through the neck  20  of the bottle  10  is indicated by the arrows F, while the path of the liquid to be introduced to the bottle  10  by the action of a tap  70  from the filling section  45  of the machine  100 , is shown by the arrows F 1 . 
     The bottle  10  is pushed toward the filling nozzle  85  set on a table or plate  75  actuated by a transmission system  15  and made to tightly adhere to a centering cone  25 , so as to gradually expel the air contained therein as the vacuum is applied along the tube  35 . 
     The tube  30  is shifted, together with the body of the bottle  10 , by the push of the table or plate  75 , while the spring  40  is used to keep the tap  70  closed; moreover, the tap  70  comprises a tightly sealing rubber ring, which seats on the neck  20  of the bottle  10  during the filling phase. 
     In particular, FIG. 2 shows under no.  602  a chamber inside the tank  61 , connected to the fitting  51  of the vacuum pump  52 , which receives the upper end of the tube  35 ; this embodiment allows to keep the air, picked up from the neck  20  of the battle  10 , separated from the inert gas contained in the chamber  600  of the same reservoir  61 , so as to prevent the oxidation of the liquid contained in the bottle  10 . 
       521  schematically indicates a pump for insufflating inert gas,  500  a tube for introducing inert gas to the machine  100 , and  601  a venting valve for the inert gas, while the arrow F 2  indicates the path followed by the gas within the machine  100 . 
     FIG. 3 shows the same elements present in the FIGS. 1 and 2 by the same reference numbers; moreover,  17  indicates a first cam engaging with the wheel  16  of a piston actuating the system  15 , which in turn transmits the rotating motion of the cam  17  to the table or plate  75  supporting the bottle  10 . Therefore, the table  75  moves in an alternating manner, so as to appropriately advance or retrieve the neck  20  of the bottle  10  from the filling section  45  and the centering cone  25 , depending on the different positions assumed by the cam  17 . 
     Moreover, the filling section  45  includes a cursor  11  rigidly connected to the filling tap  70  and connected by a precharged spring  12  to a bracket  13 , which carries the centering cone  25  of the bottle  10 , within which the nozzle  85  of the tube  30  is allowed to slide. 
     The tap  70  is connected to the cam  17 , so that the entrance of the liquid into the bottle  10  is governed by the rotation of the cam  17 , which can assume various operating positions. 
     The ending  18  of the tube  35  receiving the air drawn from the bottle  10  crosses the tank  61  and arrives at the valve  19 , which can be commuted between three different positions of the machine  100 , thanks to a second cam  21  mechanically or electro-mechanically connected to the same cam  17 , which transmits the motion to a connecting eyelet  22 . The latter connects the end  18  of the tube  35  alternatively to a first chamber  31  filled with inert gas, to a second chamber  32  at a slight depression, and to a third chamber  33  under a high vacuum. 
     The connection between the ending  18  of the tube  35  and each chamber  31 ,  32 , and  33  occurs by changing the position of the eyelet  22 , which has one ending attached to the tube  22  opposite to the ending  18  and the other moving, under the action of the cam  21 , along a circular arc of about 90 degrees; the eyelet  22  crosses an arc of about 45 degrees to commute between one position and the other. 
     The particular geometric profile of the cam  17  allows to separate the operating phases relating to the motion of the bottle  10  and the commuting action of the valve  19 . The FIG. 6 schematically reproduces the geometric profile of the cam  17  controlling the table  75  to move the bottle  10 . 
     The E-M portion of the profile controls the entering of the bottles into the filling section  45  of the machine  100 , while the time interval corresponding to the profile portion E 1 -G 1  run by the cam  17  governs the commuting action of the valve  19  to a position in which the tube  35  connects to the chamber  32  operating under a slight depression. 
     The profile portion E-D commands the slow and gradual motion of the bottle  10 , as it approaches the rubber sealing ring of the tap  70 . 
     The portion C-D takes care of a complete contact sealing of the rubber ring mentioned above, while holding the tap  70  in a closed position; during this time interval, the cam  21  controls in succession the commuting phase of the valve  19  to a position aspirating the gas present in the bottle  10  (pre-evacuating phase, during a time interval corresponding to the portion D 1 -C 4  of the geometric profile run by the cam  17 ), the inert gas inflating phase in the bottle  10 , corresponding to the portion C 3 -C 4  of the profile (when the eyelet  22  connects the chamber  31  to the tube  35 , thus allowing a quick commuting action of the valve  19 ), and the commuting action of the valve  19  working under a slight depression, corresponding to the portion C 1 -C 3  of the profile (when the eyelet  22  connects the tube  35  to the chamber  32 ), so as to allow the operation of filling the bottle  10 . The phases of pre-evacuating the gas contained in the bottle  10  and of injecting the inert gas are repeatable, depending on the user&#39;s requirements. 
     The portion B-C of the geometric profile of the cam  17  governs the quick opening action of the tap  70  for the filling step, while the portion B-L of the profile of the cam  17  relates to the filling phase of the bottle  10 . 
     It is eventually also possible to perform a forced feeding operation of the bottles  10 , during a time interval corresponding to the portion A-B 1  of the profile of the cam  17 ; before this operation, the cam  21  commands the quick commutation of the valve  19  to the position in which the tube  35  connects to the high vacuum chamber  33 , so as to generate a high vacuum in the bottle  10 . The optional operation of a forced introduction of liquid into the bottle  10 , under high vacuum conditions, allows a better performance of the plant, despite the fact that it can be effected only if the filling liquid is water. 
     The portion H-L of the cam commands, after the filling, the quick closing of the tap  70 , while the portion H 1 -G controls the motion of the bottle  10  on the rubber ring of the tap  70 , which achieves a tight sealing contact thanks to the reaction of the spring  12 . In this phase, the filling liquid rises in the tube  30 , while the valve  19  commutes so as to insufflate inert gas into the bottle  10 . The residual liquid in the tube  30  is at this point released and drops back into the neck  20  of the bottle  10 . 
     The G-M portion of the profile controls the motion of the bottle  10 , commanded by the spring  12 , during its return and the slow removal motion from the sealing ring, after the filling operation has been completed. 
     During this time interval the valve  19  commutes and the eyelet  22  connects the tube  35  with the chamber  31  to enable it to insufflate inert gas into the neck  20  of the bottle  10 , which is slowly removed from the section  45 . 
     In this manner, the tube  35  can very slowly withdraw from the neck  20 , so as to maintain the inert gas in the neck  20  of the bottle  10  in a very stationary condition, above the free surface of the liquid introduced. The procedure is ended by the capping phase of the bottle  10 . 
     Finally, the particular structure of the machine  100 , where the valve  19  is arranged opposite one of the endings and allows performing the operations of aspirating air from the bottle and/or of injecting the inert gas, allows a complete sanitizing action of the machine  100  itself, by acting only in the vicinity of the free ending  18  of the tube  35 . 
     Alternative embodiments, as illustrated in particular in FIGS. 7,  8  and  9 , envision the use of a membrane gasket indicated by  565 , connected on one side to the upper end of the tube  30  next to the level  56 , and on the other side to the fixed body  566  of the tap  70 , for the purpose of guaranteeing a seal at the upper parts of the tube  30  during the filling and/or sanitizing steps. 
     The gasket  565  allows to achieve an effectively tight seal with respect to both the tank  61  and the mobile elements fitted inside the tap  70 , during the filling operations. 
     In order to improve the working action of the gasket  565  and therefore ensure an extra sealing action at various points of the machine  100 , an eccentric element  555  is preferably used, connected to the fixed body  566  of the tap  70 ; the application of a pressure on the eccentric element  555  produces an increased sealing action between the mobile elements arranged in the machine  100 , while rotating the eccentric element  555  produces a shifting motion of the tap  70  toward the tank  61 , with the resulting squashing of the gasket  565  against the tank  61  itself, so as to achieve an even more effective seal at the level  56 . 
     Moreover, as schematically shown in particular by FIG. 9, the centering cones  25  may be mobile with respect to the tap  70 , so as to ease the washing and sanitizing operations, while releasing the nozzle  85 . This can be obtained by connecting each centering cone  25  to a mobile part  615  made of elastic materials and/or composed of pneumatic means, and of a supporting rod  616  arranged in a position parallel to the tubes  30  and  35 . The supporting rod  616  may be attached to the machine  100  at the level  56  or opposite to the tap  70 , as shown for example in FIG.  10 . 
     According to the invention, the filling machine  100  finally allows to achieve, by a small variant, a self-leveling action of the bottle  10 , even while operating under a slight depression or by gravity. 
     After having accomplished a tight seal between the bottle  10  and the tap  70  while simultaneously insufflating inert gas into the chamber  60  of the tank  61  along the conduit  455  in accordance with the direction of the arrow F 5  in the FIGS. 11 and 12, it is in fact possible to perform the operations of pre-evacuating the air from inside the bottle  10  across the tube  35 , according to the direction of the arrow F 6  shown in FIG. 13, and of introducing inert gas according to the direction of the arrow F 3  shown in FIG. 14, always from the tube  35 , across the nozzle  85  and into the bottle  10 . 
     At the end of the phases of filling the bottles  10  and of closing the tap  70 , as shown by the FIGS. 15,  16  and  17 , respectively, which are accomplished by aspirating inert gas from the neck  20  of the bottle  10  according to the direction of the arrow F and consequently by inducing the falling of the liquid according to the direction of the arrows F 1 , the liquid level rising back up along the neck  20  of the bottle  10  is necessarily variable and therefore changes the filling level of each bottle  10 . In order to prevent this inconvenience, the commuting action to open and close the valve  19  set into the tank  61 ,  705  or outside the same is usually programmed so as to manually or automatically block the exit of liquid from the nozzle  85  at the appropriate time, while taking into account that the liquid rises in the neck  20  of the bottle  10  because of the aspirating action of inert gas from its interior. 
     This method is however extremely costly in terms of the implementing time required, and above all poorly reliable. 
     Alternatively, according to this invention, the chamber  31  containing inert gas under pressure is connected by a tube  155  with the tap  70  directly in contact with the neck  20  of the bottle  10  (FIG.  18 ); this achieves a pressure differential at the neck  20  of the bottle  10 . 
     The resulting effect is that of achieving a precise liquid level in the bottle  10 , with the possibility of aspirating all the excess liquid spilled from the neck  20  of the bottle  10 , which rises along the tube  35  and exits from the free end  18 ; at this point, the excess liquid can again be introduced to the tank  61 , as shown by the arrows F 4  of the FIG. 18, or eliminated by causing it to exit from the tank  61 , outside the filling machine  100 . 
     If the liquid is reintroduced to the tank  61 , it is possible to exploit the negative pressure differential of 0.5 bar existing in its interior, so as to obtain a total differential pressure of about one bar between the level corresponding to the tap  70  and the level of the liquid outlet from the tank  61 . 
     Finally, even in this case the procedure of filling the bottle  10  ends with the slowly insufflating phase of inert gas from the nozzle  85  inside the neck  20  of the bottle  10 , simultaneously with the phase of withdrawing the neck  20  of the bottle  10  from the tap  70  by actuating the system  15  which moves the plate  75 ; reference to FIGS. 19,  20  and  21  should be made in this regard. 
     The adjustment of the liquid level in the bottle  10  may also be simultaneously effected on all the taps  70  of a filling machine  100 , thanks to a single electric actuator  705 , capable of rotating a common sprocket  557  which transmits the motion to the threaded elements  558  and  559  of the taps  70 , suitable for a vertical shifting of the same (FIG.  10 ). 
     The adjusting process is run by an electronic programming and controlling system, which processes the data relating to the portion of the tube  35  introduced into the neck  20  of the bottles  10  and of the vertical shifting of the tap  70  with respect to a reference level and the volume of liquid which rises up the tube  35  itself and consequently commands the flow of liquid from the nozzle  85  and the relative motions of the tap  70 . 
     Attention is drawn to the fact that, as schematically shown by the FIG. 10, between one tap  70  and another of a filling machine  100 , a crown of free wheeling sprockets  706  is provided, which can be engaged by a series of gears, mounted on pneumatic devices  707 , which allow the automatic opening of all the taps  70  connected to a machine  100 , so as to carry out the usual sanitizing operations, consisting in an accurate washing of the internal parts of the machine  100  in contact with the liquid to be bottled, while keeping the tap  70  open and in a freely draining position. In this case, the sanitizing operation can be carried out directly at the tap  70 , even without the centering cones  25 . 
     The description given clearly outlines the characteristics of the machine for the filling of containers, in particular of bottles and the relative filling method which are the object of this invention, as well as its resulting advantages. These concern the following aspects in particular: 
     an absence of oxidation of the liquid contained in the bottle; 
     an effective seals at the neck of the bottle during the filling phase; 
     a possibility of performing the phases for pre-evacuating the air in the bottle and insufflating inert gas into the neck while preventing the contamination of the liquid with oxides; 
     a complete sanitizing of the machine by acting on a limited portion of the same. 
     It is obvious that numerous variants may be applied to the machine for the filling of bottles and its method of filling, which are the object of this invention, without abandoning the principles of novelty embodied by the inventive concept. The materials, shapes and sizes of the illustrated details may be of any type depending on the requirements, and the same may be substituted by other technical equivalents.
A machine for the filling of containers, and in particular for the fillings of bottles, which combines advantages of a traditional isobaric machine with those of a machine operating under a slight depression, such as a good seal at a neck of a bottle and a minimum absorption of air by an introduced liquid. The machine allows performing steps of pre-evacuating air inside the bottle and insufflating an inert gas through the neck of the bottle.