TECHNICAL FIELD

The present invention relates to a filling valve for filling a container with a pourable product.

More specifically, the present invention relates to a filling valve for filling a container with a pourable food product, e.g. a carbonated pourable food product, such as beer or mineral water.

BACKGROUND ART

Filling machines typically comprise a filling station, to which empty containers are fed and which supplies, as its output, containers filled with a pourable food product.

Most filling stations basically comprise a carousel conveyor rotating about an axis of rotation; a tank containing the pourable food product; and a number of filling valves fluidically connected to the tank and fitted to the conveyor, arranged radially outwards relative to the axis of rotation of the conveyor.

More specifically, the conveyor comprises a number of container supports for positioning the mouths of the containers beneath respective valves , and for moving the containers integrally with their respective valves along an arc-shaped path about the axis of rotation. Each filling valve substantially comprises a fastening body for attachment to the conveyor and which defines a ^' filling chamber fluidically connected to the tank; and a filling head movable towards and from the fastening body in a respective direction parallel to the axis of rotation of the conveyor, so as to move from and towards the relative container.

Each filling head comprises a stopper movable inside the chamber between a closed position cutting off flow of the pourable food product to the mouth of the relative container, and an open position fluidically connecting the chamber to the mouth, thereby enabling the flow of the food product into the container.

When filling containers with a carbonated pourable food product, during the filling process each container has first to be pressurised to the same pressure as the pourable food product. More specifically, the container is pressurised by feeding a pressurisation fluid, e.g. carbon dioxide, into it, with the filling head stopper in the closed position.

The stopper of the relative filling valve is then moved to the open position, and the container is filled.

Filling may comprise a first fast-rate filling step and a second slow-rate filling step immediately after the first step. To the purpose of controlling the filling operation, each filling valve also comprises means for detecting the level of the pourable food product inside the container, which very often comprise a probe as sensing means. The probe may be an inductive probe which projects into the container once the latter is positioned beneath its relative filling valve.

Filling may be interrupted upon the pourable food product reaching the probe. Alternatively, a first fast-rate filling step may terminate when the pourable food product level reaches the height of the probe, whereas a second slow-rate filling step is started upon the pourable food product level reaching the probe, and continues as long as necessary to fill the container with a given amount of pourable food product.

whilst being filled with the pourable liquid, each container is progressively depressurised, so that the pressure above the pourable food product level equals atmospheric pressure. Depressurisation is achieved through progressive expulsion of the carbon dioxide used to pressurise the container .

A filling valve of the type described above is disclosed in EP1860057. In particular, reference is made there to a filling valve comprising a level probe consisting of a long and thin stem made of an electrically conductive material, which is preferably not coated with an electrically insulating material. Said level probe protrudes relative to an inner duct of the valve and projects into the container to be filled to the height that has been selected as the container threshold filling level. At the opposite end, the level probe is attached to the head of the plug and is operatively connected to a control and command unit, which is responsible for detecting the signal from the level probe and sending correspondingly open/close commands to the actuator of the plug.

This filling valve has the disadvantage that centring means for the level probe need to be provided, preferably moulded as one piece with the inner duct, or applied within the valve inner duct at a later stage. Either way, the centring means are positioned such as to prevent the level probe from contacting the valve inner duct, ideally in a retracted position relative to the bottom end of the valve inner duct, so that they are protected from potential damages caused by a bottle burst or excessive foaming of the carbonated pourable product.

US5501253, too, discloses a filling valve of the type described above. More particularly, US5501253 describes a level probe comprising a wire, preferably of a non-corrosive metal, the tip of which extends into the container through a gas tube of the filling valve. Only the tip of the level probe is bare and conductive relative to the liquid product being poured into the container or other ground point, whereas the rest of it is insulated.

Also for the filling valve known from US5501253 a centring/spacing member has to be provided to fix the probe at a central position within the gas tube. In particular, in this case, the centring/spacing member is designed so as to maintain a sufficiently large channel around the insulation material surrounding the wire, so that the gas may flow through it.

The manufacture of these filling valves is therefore complicated by the need to provide centring/spacing means, because the latter have to either be inserted at a subsequent stage or obtained in one piece when forming the gas duct, which inevitably imposes limitations in terms of materials and/or manufacturing methods.

Besides, since the tip of the wire constituting the level probe has to freely project into the container to perform its sensing function, and generally needs to be movable along the axis of the filling valve body, the centring/spacing means can only be arranged at a somewhat retracted position, i.e. such that the tip of the wire extends outside the centring/spacing means. As a consequence, the tip of the wire may still bend due to interaction with a container imprecisely aligned with the filling valve, or in case of breakage of a container and so forth. Since reading of the level reached by the pourable liquid in the container is based on the liquid itself closing the electric circuit upon contacting the wire tip, bending of the wire shall result in the liquid systematically getting to a level greater than the one originally set.

Furthermore, since the bending can only be detected through direct visual inspection of the gas duct, the overall quality and precision of the filling operation shall be adversely affected at least until the first scheduled maintenance.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a filling valve designed to provide a cheap, convenient solution to the above drawback typically associated with known filling valves, whilst ensuring at the same time a satisfactory accuracy of level control during the filling operation.

According to the present invention, there is provided a filling valve as set forth in Claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, a preferred, non-limiting embodiment of the present invention will be described by ^¬ way of example with reference to the accompanying drawings, in which:

- Figures 1- and 2 show schematic sectional views of a filling valve in accordance with the teachings of the present invention and a neck portion of a container to be filled with a pourable liquid in the closed (pressurisation) and open (filling) position.

BEST MODE FOR CARRYING OUT THE INVENTION

Number 1 in Figures 1 and 2 indicates as a whole a filling valve designed to form part of a filling station of a filling machine for filling containers 2 with a pourable product. More specifically, the pourable product is a carbonated pourable food product, non-limiting examples of which are beer and mineral water.

Non-limiting examples of the material of which containers 2 are made are glass, plastic or cardboard.

The filling station is supplied with empty containers 2, and fills containers 2 with the pourable food product.

The filling station substantially comprises:

- a tank containing the pourable food product (not shown), and a fluid, e.g. carbon dioxide (shown by bubbles in Figures 1 and 2) , for pressurising containers 2 before they are filled; and

- at least one filling valve 1 and one respective support (not shown) for containers 2, each support being mechanically linked to a respective actuator (not shown) for moving the support and, hence, the container 2 to and from the at least one filling valve 1 along a vertical axis thereof .

Preferably, when the filling machine comprises more than one filling station, then the filing valves 1, as well as their respective supports and actuators, are fixed on a carousel conveyor (not shown) forming part of the filling machine, rotating about a respective vertical axis, and from which the filling valves 1 and the supports project.

In other words, in that case, filling valves 1 and supports are borne by the carousel conveyor, so that filling valves 1 are rotated by the conveyor, and supports are moved to and from filling valves 1 along respective vertical axes by respective actuators.

Furthermore, in that case, the machine generally comprises only one first tank and one second tank, which are annular, so that all the filling valves 1 comprised in the station can be connected to the first tank and to the second tank.

In a known manner, each container 2 comprises: - a mouth 7, through which container 2 is filled by the filling machine, and the food product is subsequently poured from container 2 ;

- a bottom wall opposite to mouth 7; and

- a neck portion 9 adjacent to mouth 7 and bounded at the top by mouth 7, and at the bottom by a part constituting the body 10 of the container, so the body 10 is located between the mouth 7 and the bottom wall.

In the following description, reference will be made, for the sake of simplicity, to one filling valve 1 and relative container 2.

Filling valve 1 substantially comprises a fastening body 11 for attachment to the conveyor (not shown) and stopper means 12 that slides to and from container 2 along an axis A inside fastening body 11. In particular, stopper means 12 comprises a plug.

More specifically, the fastening body 11 comprises an annular wall 13, of axis A, internally defining a cavity 14 connected fluidically to the tank. Furthermore, the wall 13 comprises a shoulder 15 facing axis A.

More specifically, shoulder 15 comprises a substantially truncated-cone-shaped portion 16; a cylindrical portion 17, of axis A; and a beveled connection portion 18 interposed between portions 16,17.

The cylindrical portion 17 defines a circular opening 19 defining the bottom of cavity 14, and the portion 16 tapers towards the opening 19. The connection portion 18 typically cooperates with an annular seal 23 designed to rest on the mouth 7 of the container 2.

The stopper means 12 substantially comprise:

- a top end portion (not shown) upon which a force is exerted, in use, along axis A by an actuator;

- a first tubular body 20 of axis A; and

- a bottom end portion 21 opposite the top end portion and defining a projection 22.

More particularly, the projection 22 comprises a wall 24 sloping relative to axis A, projecting from the body 20 towards the wall 13, and tapering towards the opening 19.

The tubular body 20 of the stopper means 12 internally defines a cavity 26, preferably extending substantially along axis A, which cavity 26 is fluidically connected to the tank.

Furthermore, the stopper means 12 are movable, upon operation of the actuator mentioned above, between:

- an open position (see Figure 2), in which the wall 24 is detached from and located above the portion 16 of the shoulder 15, so as to allow the pourable food product to flow through the opening 19 from the cavity 14 into the container 2 ; and - a closed position (see Figure 1), in which the wall 24 cooperates in fluid-tight manner with the portion 16 of the shoulder 15, thereby cutting off flow of the pourable food product through the opening 19 and into the container 2.

Advantageously, the filling valve 1 also comprises a second tubular body 27, of axis A, projecting from the bottom end portion 21 to the container 2 and loosely through the opening 19. More specifically, the tubular body 27 extends coaxially inside the stopper means 12, within the cavity 26.

The tubular body 27 internally defines a tubular conduit 28 comprising a cylindrical portion 29 of axis A that extends between a bottom opening 30 and a top opening 31 opposite the bottom opening 30. More precisely, the bottom opening 30 faces, and is fluidically connected to, the inside of the container 2, when the container 2 is in a filling position with the mouth 7 resting against the filling valve 1 (see Figure

1) -

The tubular body 27 is movable along with the stopper means 12 between a filling position (see Figure

2) and a pressurisation position (see Figure 1) and is in fluidic connection with the tank.

The filling valve 1 further comprises an annular conduit 32 of axis A, bounded radially between the body 20 and the body 27, and comprising an opening 33 that faces the inside of the container 2, when the container 2 is in the filling position with its mouth 7- resting against the filling valve 1.

More specifically, the tubular body 27 extends through opening 33, and the axial distance between openings 30 and 19 is greater than the axial distance between openings 33 and 19. In other words, the opening 30 is lower than the opening 33 inside the container 2 in all operating configurations (see Figures 1 and 2) .

The filling valve 1 therefore comprises a first flow line, which is defined by the tank and the cavity 14, and is connectable selectively by stopper means 12 to the mouth 7 of the container 2, and which serves to fill the container 2 with the pourable food product.

The filling valve 1 also comprises a second flow line, which is at least partly defined by the annular conduit 32, along which carbon dioxide may be fed from the tank into the container 2 in order to pressurise the latter before it is filled with the pourable food product .

Finally, the filling valve 1 comprises a third flow line, which is at least partly defined by the second tubular body 27, along which at least the carbon dioxide excess supplied during the pressurisation phase (Figure 1) may be expelled upon filling (Figure 2) the container with the pourable food product.

Advantageously, the" tubular body 27 is made of an electrically conductive material, preferably a metallic material, such as stainless steel or other non-corrosive metal. The bottom end 34 of the tubular body 27 which extends into the container 2 through the mouth 7 is bare and conductive relative to the pourable food product or other ground point. Except for the bottom end 34, the tubular body 27 is insulated where it runs upwardly through the stopper means 12.

The tubular body 27 has a non-insulated top end (not shown) that projects into an electrical connector plug. At its top end, the tubular body 27 is operatively connected with a control and command unit 35 for example by means of a suitable wiring, or by wireless systems. In other words, the tubular body 27 is adapted to function as a probe for detecting the reaching of a predetermined level of pourable food product in the container 2 being filled.

To this purpose, the control and command unit 35 is configured to detect a signal from the tubular body 27. In response to detecting this signal, the control and command unit 35 is configured to send a suitable open/close command to the actuator responsible for lifting/dropping the stopper means 12.

More particularly, the control and command unit 35 is adapted to detect a -variation of an electrical entity, such as a current or a voltage, which occurs upon the pourable food product contacting the bare bottom end 34 of the tubular body 27, and, accordingly, provide for the actuator to drop the stopper means 12 and interrupt the flow of pourable food product into the container 2.

Operation of the filling valve 1 shall be described in the following. Reference shall first be made to the condition depicted in Figure 1, in which the mouth 7 of the container 2 rests against the filling valve 1, supply of carbon dioxide (the pressurisation gas) is activated, and the stopper means 12 are in the closed position.

In this condition, carbon dioxide flows from the tank along the annular conduit 32 and into the container 2 through the opening 33, so as to fill the container 2 and bring it to the same pressure at which the pourable food product is kept in the first tank 3. At the same time, fluidic connection of the third flow line (the tubular conduit 28) with the tank is interrupted.

Next (Figure 2), the actuator (not shown) lifts the stopper means 12 and the tubular body 27 to detach the wall 24 of the projection 22 off the portion 16 of shoulder 15, thereby fluidically connecting the cavity 14 to the inside of the container 2.

In the meantime, the fluidic connection of the second flow line with the tank having been interrupted, the carbon dioxide accumulated in the container 2 escapes through the conduit 28 which has, to this purpose, been fluidically connected with the tank.

Because of the design of the bottom-end portion of the fastening body 11 and the stopper means 12, close to the opening 19, the pourable food product is driven to flow adjacent to the edge of the container 2 at its neck portion 9 as it fills the body 10 of the container 2.

Alternatively, at least during a first portion of the filling phase, e.g. whilst the pourable product is accumulating in the bottom portion of the inner volume defined by the body 10 of the container 2, the fluidic connection of the second flow line with the tank may be maintained. Thus, at this stage, the carbon dioxide accumulated in the container 2 escapes through both conduits 28 and 32.

When the level of the pourable food product in the container 2 reaches the bottom end 34 of the tubular body 27, a variation of an electrical entity is detected such that the control and command unit 35 stops the flow of pourable food product by having the actuator drop the stopper means 12 , thereby closing the opening 19. Once the flow through the opening 19 has been interrupted, i.e. once the stopper means 12 have returned to their closed position, depressurisation of the container 2 may also advantageously be achieved by expulsion of the pressurisation fluid along the second flow line.

In other words, the bottom end 34 of the tubular body 27, when raised together with the stopper means 12 in the filling position (Figure 2) defines a threshold level at which filling of the container 2 is interrupted.

The advantages of the filling valve 1 according to the present invention will be apparent from the above description.

In particular, the filling valve 1 provides for determining when the pourable food product reaches a given level inside container 2 with increased accuracy with respect to other known filling valves, because the probe function is served by the tubular body 27, which has a remarkably greater rigidity than a metallic wire, hence its position inside the container 2 being filled cannot be affected by bending caused e.g. by interaction with a container 2.

At the same time, the filling valve 1 provides for separate flow lines for introduction and expulsion of the pressurizing gas, which is fed into the container 2 along the annular conduit 32 and expelled, for the most part, during the filling phase, through the tubular conduit 28.

When filling a container 2 with a carbonated food product, foam often forms within the container 2. If, whilst filling a container 2, this foam accumulates on the pressurisation ducts, the successive filling of another container 2 may be adversely affected in terms of precision, because the flow of pressurisation fluid would basically spray the foam into the empty container just placed in its filling position.

In this respect, the filling valve 1 of the invention is particularly advantageous because three separated flow lines are provided for filling the container with the pressurisation fluid; for introducing the food product.; and for expelling the pressurisation fluid, respectively. As a consequence, even when some foam accumulates at the bottom end 34 of the tubular body 27 (i.e. at the lower end of the third flow line) when the next container 2 is pressurised, the pressurisation fluid is fed into the empty container 2 through the second flow line, hence the likelihood of foam contamination is greatly reduced.

Finally, it shall appear that changes may be made to the filling valve 1 as described and illustrated herein without, however, departing from the scope of protection as defined in the accompanying claims .