The present invention relates to a valve group for performing filling under aseptic conditions, in particular for filling containers with liquid alimentary products of varying density comprising also, where applicable, alimentary products in small pieces.

The filling valves of the known type have various drawbacks.

A first drawback consists in the fact that the obturator of the valve is generally provided with a stem which slides between external guides and these guides are positioned far from the seat of the valve opening through which the liquid flows out during filling of a container: this does not guarantee a high degree of precision of the obturator, which may be subject to misalignments with respect to the central axis of the opening owing to excessive play in the vicinity of the opening, resulting in early wear and poor reliability.

A second drawback consists in the fact that the valves of the known type have numerous zones where ensuring the presence of aseptic conditions is quite critical. These zones consist in particular of the zones where joints or seals are present. In fact, seals between metals are technically difficult because they require surfaces which are machined in a very precise manner and it is therefore preferred to use seals which are certainly more economical, but create zones which are difficult to clean and sterilise.

In order to ensure conditions of sterility of the stems of said valves which repeatedly enter and leave the zone affected by the product,"steam barriers"are used, namely zones limited by gaskets or seals, which are permeated with steam: basically the stem is sterilised by the steam every time it passes from the external environment to the zone in contact with the product, but this solution is costly and complex from a plant engineering point of view, in particular when tens or hundreds of valves are present.

The valves of the known type are moreover generally somewhat heavy and bulky and have a high degree of inertia, this being the cause of inaccuracies in the quantity of filling liquid, with performances which are often unacceptable.

DISCLOSURE OF INVENTION.

The object of the present invention is that of eliminating the abovementioned drawbacks and providing a light and compact filling valve which is suitable for the treatment of pulps or liquids with solid suspensions and can be easily cleaned and operates under aseptic conditions with only one limited zone which may be of a critical nature.

A further object is that of ensuring a high degree of precision of the obturator together with a considerable speed of opening and closing of the obturator itself.

Said objects are fully achieved by the valve group according to the present invention, which is characterized by the contents of the claims indicated below and in particular by the fact that the obturator, which is internally hollow, is formed so as to be slidable on guide means which are inside the obturator itself at least in the vicinity of the valve opening.

The valve also comprises a membrane of the elastic type which lines entirely the obturator and also acts as a sealing gasket during closing of the opening.

BRIEF DESCRIPTION OF DRAWINGS.

These and other characteristic features will emerge more clearly from the following description of a preferred embodiment illustrated, purely by way of a non-limiting example, in the accompanying illustrative plates, in which: -Figures I and 2 show a vertical cross-section through the middle of the valve in the open and closed conditions, respectively.

BEST MODE FOR CARRYING OUT THE INVENTION.

With reference to the Figures, I denotes overall a valve filling group of a filling machine

schematically indicated by 2.

The valve group has a valve body 3 which is provided at the bottom with the opening 4 through which the product intended to fill an underlying container 5 flows out. The product, which is a liquid or pulp alimentary product which may contain various solid suspensions, is supplied into the valve body through a supply duct 6.

An obturator 7, which is internally hollow, slides inside the valve body and is kept in the normally closed position by the action of a spring 8 which is enclosed between an upper closing element 9 of the valve body and the upper part of the obturator itself, the latter being formed as a cylindrical cavity with an abutment surface 10 able to seat the spring 8.

The obturator 7 is guided during its sliding movement by guide means comprising a fixed internal guide 11 which extends in an original manner into the vicinity of the opening 4 so as to avoid play during sliding of the obturator and ensure with precision that it is correctly positioned coaxial with the opening 4.

An arrow 12 indicates the entry of air which, when it is required to open the valve, is injected by pneumatic means (not shown) into a chamber 13 with a pressure such as to overcome the action of the spring and cause raising and the movement back upwards of the obturator as far as an end-of-travel stop 14.

A breather duct 15 is provided inside the guide 11 so as to allow the evacuation of the air from a small chamber 16 located at the base of the guide 11 during opening of the valve and the movement back upwards of the obturator with respect to the guide.

17 denotes a tip or a bottom terminal part of the obturator 7.

A membrane 18 of the flexible and elastic type in an original manner envelopes the whole of the obturator, being vulcanised at the tip 17 and fixed inside an annular seat 19 of the valve body 3.

During closing of the valve, the membrane 18 acts as a sealing and closing gasket, adapting itself and being compressed and deformed so as to close the opening 4 of the valve.

Injection of air into the chamber 13 produces the upward movement of the obturator 7 and the membrane 18 frees the opening 4, allowing the product to flow out.

Removal of the air inside the chamber 13 produces, on the other hand, the downward movement of the obturator (when the action of the spring overcomes the action of the air) and closing of the opening by the membrane.

The original hollow-and therefore light-obturator 7 results in a low inertia and a fast opening and closing speed of the valve with consequent greater precision in the quantity of liquid introduced into the container 5.

The guide 11 inside the obturator is positioned so as to guide at least the bottom part of the obturator in the vicinity of the opening and results in very compact dimensions of the valve and great precision during closing, preventing misalignment which could cause undesired loss of liquid and uncontrolled wear.

The membrane 18 which completely surrounds the obturator facilitates the cleaning operations and results in a drastic reduction in the zones where maintaining the aseptic conditions could be quite critical, limiting to only one zone (the annular zone where the membrane is inserted inside the seat 19) any possibility of contamination.