The invention refers in particular to the sector of filling of containers with food preserves.

The prior-art filling machines, known as"piston filler" machines, comprise a supply line of containers to be filled, an evacuation line of the. filled containers and a filling apparatus placed between the supply line and the evacuation line. The filling apparatus is generally inserted into a rotating structure and comprises a piston filler, wherein a piston is mobile. with reciprocating movement inside a cylindrical liner in such a way. as to suck the product from a system of supply conduits and subsequently direct it towards a nozzle that is located near an inlet mouth of a container waiting to be filled. By adjusting the stroke of the piston within the liner, it is possible to vary the volume of product sucked by the system of supply conduits and delivered into the container; this means that the piston has both a function of propelling the product towards the container and a function of metering the quantity of product delivered into the container.

Filling machines are also known that process substantially liquid products, these are so-called"hot fill"filling machines wherein the product is packaged by making it flow down supply conduits through the force of gravity or through the effect of a vacuum created in the container to be filled.

With the"hot fill"filling machines it is possible to package a food product by. maintaining it at a relatively high temperature.

The above-mentioned"hot fill"filling machines are completely unsuitable for processing fluid products that have largish solid parts, for example pieces of tomato or mushroom or meat, dispersed in a liquid.

This inasmuch as the transition sections of the different conduits and in particular the section of the nozzles clog up when crossed by solid parts.

It is therefore necessary to provide two distinct types of machine, one for processing substantially liquid products and another for fluids comprising largish solid parts.

This constitutes a significant increase in costs and results in significantly complex systems.

One object of the invention is to improve prior-art filling machines.

Another object is to avoid having to resort to different filling machines according to whether a substantially liquid product or a fluid product containing largish solid elements has to be delivered into the containers.

A yet further object is to provide a filling machine that is more versatile than those of the prior art.

A further object is to provide a machine that can fill a product that is maintained at a preset temperature.

Another further object is to provide a"piston filler"filling machine that can package in an optimum manner products that are normally packaged in"hot fill"filling machines and with the typical performance of the latter.

In a first aspect of the invention, an apparatus is provided for filling containers, comprising a nozzle body having an inlet and an outlet, characterised in that said nozzle body may alternatively receive a first shutter member or a second shutter member, both being shiftable between an open position, wherein they allow the passage of a product respectively less and more homogenous through said outlet and a closed position wherein they prevent the passage of said product.

In a second aspect of the invention, a method is provided for filling containers, comprising predisposing a nozzle body having an inlet and an outlet, characterised in that said predisposing comprises. alternatively mounting a first shutter member or a second shutter member, both being shiftable between an open position, wherein they allow the passage of a respectively less and more homogenous product through said outlet and a closed position wherein they prevent the passage of said product.

In this way it is possible, when the first member is mounted in the nozzle body, and is kept in a position far from the outlet, that a product comprising largish solid parts will pass through the body of the nozzle and exit from said outlet to. fill the container. On the other hand, when the second member is mounted, the latter may be taken to a position wherein it interferes with said outlet in such a way that the openings with which'it is equipped enable a substantially liquid product to exit towards the container.

Owing to the invention it is thus possible, by mounting the first shutter member, to fill a container with a fluid product that has largish solid parts, or, after dismantling the first shutter member and mounting the second shutter member, to make a substantially liquid product exit from the openings of the latter. In one embodiment, the nozzle body is mounted on a filling machine provided with a piston metering apparatus, arranged upstream of the aforesaid nozzle body.

We observe that when the first shutter member is mounted the product is pushed towards the nozzle body by the action of the piston with which the piston metering apparatus is provided.

When on the other hand the second shutter member is mounted,. the piston can be kept stationary in relation to the liner wherein it is inserted, as the substantially liquid product that flows through the body of the nozzle can descend through force of gravity from a container thereabove.

In a third aspect of the invention, the use of a filling machine equipped with a piston metering unit is provided for, wherein a product to be packaged is made to flow towards a container to be filled whilst the piston of said piston metering unit is kept stationary in relation to the liner wherein it is inserted.

The product to be packaged may proceed towards the container to be filled through the effect of gravity, or through the effect of slight overpressure in relation to the inside of the container.

In this way, it is possible to obtain with a"piston filler" filling machine substantially the same performance as with a "hot fill"filling machine.

The invention may be better understood with reference to the attached drawings, which illustrate a non-limiting example of an embodiment, wherein: Figure 1 is a diagram of a filling machine of containers; Figure 2 is an enlarged detail of a piston metering unit and of a nozzle body for filling a container; Figure 3 is a longitudinal section of a nozzle body and of a first shutter member in a closed position; Figure 4 is a section like the one in Figure 3, but with the first shutter member in an open position; Figure 5 is a section-like the one in Figure 3, but showing a second shutter member mounted in place of the first shutter member ; Figure 6 is a section like the one in Figure 4, but showing a second shutter member mounted in place of the first shutter member.

With reference to Figures 1 and 2, a filling machine 2 is shown near a conveying line of containers 6 to be filled and/or a line of evacuation of the filled containers 6. The filling. machine 2 comprises a plurality of filling apparatuses 8 wherein the containers 6 are located to be filled. Each

filling apparatus 8 is equipped with a mobile plate 9 the height of which is adjustable, whereupon the bottom of each container 6 to be filled is located. A main tank 10 containing a product P to be packaged is located at a greater height than the filling apparatuses 8. A main supply conduit 12 of the product P leads away from a bottom portion of the main tank 10, which main supply conduit 12 discharges into a manifold 14 located immediately above the filling apparatuses 8. From the manifold 14 a plurality of secondary supply conduits 16 lead away, each one of which supplies a piston metering unit 18 with interposition of a respective shut-off valve 20. From each piston metering unit 18 an intermediate conduit 22 emerges along which a nozzle delivering device 24 is located having an outlet 25 directed towards a mouth of a respective container 6 to be filled. Each intermediate conduit 22 extends into a respective secondary return conduit 26, with interposition of a further shut-off valve 28. The secondary return conduits 26 discharge into a return manifold 30, wherefrom a main return conduit 32 emerges, discharging into a recovery tank 34 of the product P. From a portion of the bottom of the intermediate tank 34, an extraction conduit 36 leads away, through which, by means of a pump 38, the product P is, if necessary, sent to proper heating/sterilisation units (not shown) wherefrom the product P is returned inside the main tank 10 by means of an inlet conduit 40.

With particular reference to Figure 2, the piston metering unit 18 comprises a liner 42 inside which a metering piston 44 is slidable with a reciprocating movement that aspirates the product P from the secondary supply conduit 16 through the shut-off valve 20 and an elbow conduit 46 mounted on a head 48, to which the liner 42 is screwed. When the apparatus operates as a"piston filler", after suction of a quantity of product P corresponding to the volume defined by the piston 44 during its stroke, the shut-off valve 20 is activated so that

when the piston 44 nears the head 48, the product P cannot retreat along the secondary supply conduit 16 but has to proceed along an initial stretch of the intermediate conduit 22, which leads to the delivering nozzle 24.

With reference to Figure 3, the delivering nozzle 24 comprises a nozzle body 50 equipped with an inlet 52 communicating with the outlet 25 by means of a tubular cavity 54. In the cavity 54 a first shutter member 56 is slidingly mounted having an elongated cylindrical form that has one of its ends coupled with a transversal element 58 fixed to a corresponding end of a rod 62 of a further actuating piston 60 slidable in a further cavity 64 obtained in the nozzle body 50 and arranged parallel to the cavity 54. The further piston 60 may run inside the further cavity 64 through the action of pressurised air that acts alternatively on each of its faces. In the closed position shown in Figure 3, the free end of the first shutter member 56, i. e. the end opposite the end engaged by the transversal element 58, occupies the outlet 25, thereby preventing the product P from exiting through the latter. In a first operating mode, the product P, pushed by the action of the piston'44, may flow along the elbow conduit 46 if the further shut-off valve 28 is kept shut and the shut-off valve 20 is kept open. Alternatively, in a second operating mode, the product P may pass from the inlet 52 to a return chamber 66 of the nozzle body 50 and proceed along the secondary return conduit 26 after the further shut-off valve 28 has been opened and the shut-off valve 20 is kept shut.

This second operating mode enables the different conduits and the valves. with which the product P interacts to be kept at a temperature near the temperature of the product P.

In Figure 4 by contrast, an open position of the first shutter member 56 is shown wherein the first shutter member 56 is shifted by the further piston 60 to a position far from the outlet 25 in such a way that the product P can freely flow

from the inlet 52 to the outlet 25 under the action of the piston 44, whereas the further shut-off valve 28 is in a closed position, wherein it prevents the product P from flowing along the secondary return conduit 26. The dimensions of the inlet 52 and of the tubular cavity 54 and of the return chamber 66 are selected in such a way that a flowing product P containing largish solid parts that are not shown can pass through them.

The outlet 25 is defined in its part nearest the container to be filled 6 by an end body 65 connected to the nozzle body 50 by a first screw 84.

With reference to Figure 5, the same delivering nozzle 24 is shown wherein, instead of the first shutter member 56, a second shutter member 68 is mounted in the cavity 54. In the closed position indicated in Figure 5, the part of the second shutter member 68 furthest from the transversal element 58 has a through transversal hole 70 that does not communicate with the inlet 52. The inlet 52 on the other hand communicates with an annular chamber 72 defined between the tubular cavity 54 and an intermediate stretch 74 of the second shutter member 68 having a smaller transversal dimension than the remaining part of the second shutter member 68. The'annular chamber 72 furthermore communicates with a bypass conduit 76 that discharges in the return chamber 66.

The outlet 25 is obstructed by a terminal part 78 of the second shutter'member 68 that is provided with a gasket 4 that prevents the passage of the product P through the outlet 25.

In the closed position shown in Figure 5 the product P may pass from the inlet 52 to the return chamber 66 through the annular chamber 72 and the bypass conduit 76 through for example the action of the force of gravity whereas the piston 44 is kept stationary, i. e. motionless inside the liner 42.

The bypass conduit 76 is partly situated inside a further end body 77 that is mounted on the nozzle body 50 in place of the terminal body 65.

In the open position shown in Figure 6, the further piston 60 has shifted the second shutter member 68 to a position wherein the second shutter member 68 has its terminal part 78 protruding from the outlet 25. In this open position, the inlet 52 communicates with the transversal hole 70 and the product P can pass through a longitudinal conduit 80 that extends from the transversal hole 70 along the intermediate stretch 74 until it reaches the end part 78 and discharges laterally therefrom. From the transversal hole 70 the product P can thus pass along the longitudinal conduit 80 and emerge from the end part 78 into the container 8 to be filled. In the embodiment illustrated in Figures 5 and 6, on the nozzle body 50 a resilient ring 82, for example in rubber or in elastomeric material, is fitted in a position near the outlet 25, in such a way as to guarantee that the containers 8 are tightly positioned against it in a filling configuration.

In the filling configuration, whilst the product P enters the container 6 by passing through the longitudinal conduit 80, the air initially contained in the container 6 exits therefrom through an air space 5 defined between the housing of the end part 78 and the intermediate stretch 74 and can be discharged to the outside through the return chamber'66 : in this way the machine operates as a"hot fill"filling machine.

In the"hot fill", operating mode the pistons 44 of each filling apparatus 8 are kept stationary in the respective liners 42 by acting on the tilt a of a disk cam 11 by which all the pistons 44'are controlled. Whereas during operation of the apparatus in"piston. filler" mode the cam 11 is adjusted in such a way as to form a suitable angle in relation to a horizontal plane so that the pistons 44 can perform a desired stroke, when the apparatus is operating in"hot fill"mode,

this angle is eliminated, so that the pistons 44 do not perform any stroke in the liners 42.

A comparison between the embodiments in figures 3,4 and 5,6 shows how it is possible in quite a simple manner to remove the first shutter member 56 from the cavity 54 after loosening a screw 86 connecting to the transversal element 58 and. after dismantling the end body 65.

It is thus possible to mount the second shutter member 68 in the cavity 54 and fix it to the transversal element 58; subsequently, the further end body 77 and the ring 82 must be mounted.

To again fit the first shutter member 56 follow the procedure disclosed above in reverse order.