* * *

Field of the invention

The present invention relates to the field of safety valves for systems of distribution and/or accumulation of fluids in general, and has been developed with particular reference to siphon valves that can be used in systems for loading or loading/unloading of tanks, for example tanks carried by vehicles, such as tankers, gully emptiers, and the like, in particular for the treatment of waste water, sewage, manure, fertilizers, and liquids in general.

Prior art

Siphon valves comprise a valve body defining a cavity that houses a buoyant valve member, in general constituted by a ball made of plastic or metal material.

The valve body comprises an upper part, a lower part and an intermediate part, which extend axially and have a substantially tubular shape. The upper part is generally constituted by a first connector, which is usually straight and defines an inlet of the valve and has a radially projecting flange, which is fixed in a sealed way at the top opening of the intermediate part. The intermediate part has a lateral hole, where a second connector - frequently made up of two coupled parts - which defines an outlet of the valve is mounted in a sealed way. This second connector is substantially shaped like a U turned upside down so that its end internal to the cavity of the valve body faces towards the lower part, at a height lower than the first connector. The lower part is shaped like a cup, frequently made of transparent plastic material, and has a drain opening, associated to which is a corresponding valve, generally a manually operated valve.

Defined at the end of the outlet connector that is oriented towards the lower cup is a valve seat, in such a way that any possible accumulation of liquid inside the valve body causes raising of the buoyant valve member towards the valve seat. As may be appreciated, the distance between the valve seat and the lower cup contributes to determining a certain capacity of accumulation of liquid inside the valve body, beyond which the buoyant valve member assumes the aforesaid closing position.

A valve of the type indicated in the preamble of claim 1 is disclosed, for instance, in DE 37 14421 A. Siphon valves are typically used in the agricultural sector on sewage- spreading tankers and in the ecological sector on gully-emptier means and the like for safety purposes, i.e., for preventing, during filling of a tank, the sewage from being accidentally drawn in and ending up in a pump, thus damaging the blades/rotor thereof. For this purpose, the inlet and outlet of the valve are connected, via respective spiralled hoses, to an overflow valve that is set on the top of the tank and to a reversible pump, respectively. A connector of the tank, which functions alternatively as inlet or as outlet, is connected via a respective spiralled hose to a basin or the like, containing the sewage to be loaded.

The tank is filled by negative pressure. For this purpose, the pump is operated in a first operating mode so as to bring about intake of air into the tank. In this step, the ball valve member lies by gravity in the lower cup, in a position of maximum distance from the valve seat, and there is no passage of liquids in the valve, but only the flow of air with possible particles in suspension. However, if for any reason sewage is drawn into the valve, this tends to accumulate starting from the lower cup. The increase of the level of the sewage inside the valve body determines progressive raising of the ball valve member, which, floating on the sewage, tends to approach the valve seat. At a certain point of this rise, i.e., when the sewage accumulated in the valve body reaches a certain volume, the valve member comes to occupy a position close to the valve seat such that the flow of air drawn in causes the stable positioning of the valve member in a position corresponding to the valve seat, thereby obstructing the outlet connector and preventing passage of sewage into the pump. The pump is then stopped, and the valve associated to the lower cup is opened, in order to discharge the sewage accumulated inside the valve body: if necessary, after re-closing of the aforesaid valve, the pump is again operated in order to proceed with loading of the tank.

When, instead, it becomes necessary to empty the tank out, the pump is operated in a second operating mode, like a compressor: in this way, the pump causes air to be blown into the tank, with the sewage that is pushed out from the connector of the tank. In this step, there is thus a flow of air within the siphon valve in a direction opposite to what occurs during filling of the tank, with the ball valve member that remains, by gravity and under the action of the flow of air, substantially in the lower cup. Consequently, as may be seen, the two connectors of a siphon valve of the type referred to above can function alternatively as inlet and as outlet. There are on the other hand also known systems for loading and unloading tanks with independent circuits for drawing in air and blowing it out. Reference may be made, for example, to the document No. DE 2917198 Al, where a siphon valve of the type described is designated by 8 in Figure 1.

In the current state of the art, there exist on the market a number of types of siphon valves, which may be basically divided into valves of smallish capacity of accumulation and valves of large capacity of accumulation. The valves of the first type are mass produced standard models distinguished by light structures made of aluminium or plastic material, with interchangeable connectors having diameters ranging from 45 mm to 80 mm made of brass, with quick-coupling or threaded transparent lower cups, and are suitable for use with a maximum intake of approximately 10,000 litres per minute. The valves of the second type are, instead, custom built, frequently produced at a handicrafts level in reduced numbers directly by manufacturers of gully emptiers, and are in general made of galvanised sheet steel or aluminium, with steel connectors having diameters of up to 150 mm. These valves are on average suitable for drawing in up to 25,000 litres per minute and, in some cases, over 50,000 litres per minute.

Object and summary of the invention

In view of what has been set forth above, the object of the present invention is to provide a safety valve of the type referred to, in particular a siphon valve of large capacity, that has an improved structure as compared to the prior art, is simpler to produce, inexpensive, and flexible.

With a view to achieving the above purpose, the subject of the invention is a safety valve with a buoyant valve member, in particular for tanks carried by vehicles, as well as a corresponding production method, having the characteristics specified in the annexed claims. The claims form an integral part of the technical teaching provided herein in relation to the invention.

Brief description of the drawings

Further purposes, characteristics, and advantages of the invention will emerge clearly from the ensuing detailed description, with reference to the annexed drawings, which are provided purely by way of non-limiting example and in which:

- Figure 1 is a partial and schematic representation of a system for loading and unloading a tank or the like, comprising a safety valve according to the invention;

- Figure 2 is a sectioned perspective view of a safety valve according to a first embodiment of the invention;

- Figure 3 is a schematic cross-sectional view of the valve of Figure 2;

- Figure 4 is a sectioned perspective view of a variant of the safety valve of Figures 2 and 3;

- Figures 5 and 6 are schematic views in side elevation of a safety valve according to a second embodiment of the invention; and

- Figure 7 is a schematic view in side elevation of a variant of the safety valve of Figures 5 and 6.

Description of embodiments of the invention

Reference to "an embodiment" or "one embodiment" in the framework of the present description is intended to indicate that a particular configuration, structure, or characteristic described in relation to the embodiment is comprised in at least one embodiment. Hence, phrases such as "in an embodiment" or "in one embodiment" and the like that may be present in various points of the present description do not necessarily all refer to one and the same embodiment. Furthermore, the particular configurations, structures, or characteristics may be combined in any adequate way in one or more embodiments. The reference numbers used in what follows are only provided for convenience and do not define the sphere of protection or the scope of the embodiments.

Figure 1 is a partial and schematic illustration of a system for loading/unloading of a tank for transport and/or treatment of a liquid - which is here assumed as being sewage - where the valve according to the invention finds preferred application.

In this figure, designated by T is a tank, in particular belonging to a vehicle M, such as a tanker. The tank T has an upper opening, where a primary safety valve SV is mounted, constituted for example by an overflow valve, of any conception known in the sector. Designated by 1 is a valve according to one embodiment of the invention, in particular a siphon valve, which constitutes a secondary safety valve of the system for loading/unloading of the tank T. The valve is a two-way valve for setting in communication an internal cavity of the valve itself with the outside world. The aforesaid two ways are defined by corresponding inlet and outlet connectors, used for connecting the valve 1, via spiralled hoses HI and H2, to the valve SV and to a pump P, respectively. The pump P may be a pump that can be operated in two operating modes, as clarified previously. As may be noted, the configuration of use exemplified herein for the valve 1 is substantially the one commonly envisaged in the sector. In the preferential application, the valve 1 according to the invention is used as secondary safety valve, or non-return valve: it must, that is, intervene in all the cases where a primary safety valve - for example, represented by the overflow valve SV - were not to guarantee an adequate closing in the intake step.

It should be noted that in the sequel of the present description and in the attached claims, the aforesaid two ways of the valve 1 will be defined conventionally as "inlet" and "outlet", with reference to the primary application of the valve 1, i.e., the safety function: on the other hand, as clarified in the introductory part of the present description, in a valve of the type described herein each of its two ways can function alternatively as inlet and as outlet.

With reference to Figures 2 and 3, the valve 1 has a valve body 2, defining a cavity 3 in which a buoyant valve member 4 is housed, preferably constituted by a spherical body made of plastic or metal material, for example steel, very preferably a ball having a density of less than 1 g/cm . The valve body 2 includes an upper body part 5, which, in a preferred embodiment, comprises a cover, and a lower body part 6, preferably constituted by a cup-shaped body. In what follows, for simplicity, the aforesaid upper and lower parts will also be defined as "cover" and "cup", respectively.

Extending axially between the cover 5 and the cup 6 is an intermediate body part, designated as a whole by 7 only in Figure 2, associated in a sealed way to the upper and lower ends of which are the cover and the cup, respectively.

In a preferred embodiment of the invention, the two ways of the valve, i.e., the inlet designated by 8 and the outlet designated by 9, are both in the upper body part. For this purpose, very preferably the cover 5 is traversed by the inlet 8 and by the outlet 9 in an axial direction of the valve body 2, even though a different orientation thereof is not excluded (as described hereinafter in relation to a different embodiment of the invention).

In an embodiment of this type it is preferable for the inlet 8 and the outlet 9 to be defined by respective tubular connectors, configured as parts distinct from the cover 5 and passing through respective openings of the latter, as may be clearly seen, for example, in Figure 3, where the aforesaid connectors are designated by 10 and 11. On the other hand not excluded from the scope of the invention is an embodiment where one or both of the connectors 10 and 1 1 is/are made of a single piece with the cover 5. The lower part of the valve body, here represented by the cup 6, is provided with a drain opening 12, in particular defined at a tubular outlet 12a, which is preferably made of a single piece with the body of the cup 6. Associated to the drain opening 12, i.e., to the tubular outlet 12a, is the inlet of a valve 13 of an open/closed type of any known conception, for example a manually operated ball valve. The valve 13 preferentially has an outlet connector 13a for connection of a corresponding discharge pipe (not represented).

According to the known technique, the buoyant valve member 4 is able to assume a closing position and a plurality of opening positions with respect to a valve seat 14 that faces the cup 6, in particular defined at one end of the outlet 9. In this way, as explained in the introductory part of the present description, a possible accumulation of liquid inside the valve body 1 causes raising of the valve member 4 towards the valve seat 14, with the valve member 4 that floats on the liquid that progressively accumulates. As has been explained, in this way, beyond a certain capacity of accumulation of liquid inside the valve body 1, the buoyant valve member 4 is brought to assume the position where it closes the valve seat 14, also under the action of the suction flow from the outlet 9. It will be appreciated that the aforesaid capacity of accumulation is a function of the distance between the valve seat 14 and the lower cup 6, as well as of the dimensions of the other components involved.

According to the invention, the intermediate body part 7 comprises at least one substantially annular component 15, configured for being sealingly coupleable to at least one similar substantially annular component, so as to enable variation of an axial dimension of the intermediate part 7 of the valve body 1. In this way, by varying the number of annular components 15 that make up the intermediate body part 7 it is possible to vary the aforesaid capacity of accumulation of liquid beyond which the valve member 4 tends to move into the respective position where it closes the valve seat 14. In what follows, for simplicity, the aforesaid substantially annular components 15 will also be defined as "rings".

The cavity 3 of the valve body 1 can hence be defined by three pieces, represented by the cover 5, by the cup 6, and by just one ring 15, or else by more than three pieces when the intermediate part 7 is formed by two or more rings 15, which are the same as one another and are coupled in a sealed way to one another in a configuration where they are set on top of one another: in the example represented, the intermediate part 7 consists of three equal rings set on top of one another. With reference to the example illustrated, the rings 15 may, for example, each have a capacity comprised between 10 and 15 litres, for a capacity of accumulation of the valve roughly comprised between 25 and 50 litres. Assemblage of the valve body 2 is thus very simple, involving simple fixing in a sealed way of the cover 5 and of the cup 6 at the two axial ends of the intermediate body part 7 formed by one or more rings 15, after the valve member 4 has been set inside the valve body.

The solution also enables benefits of standardization of production and management of supplies given that the same basic components (cover, cup, and rings) can be mass produced and then used for making valves having different capacities by varying the number of rings 15 used.

In one embodiment, at least one between the cover 5 and the ring 15, or each ring 15, is made of mouldable plastic material, for example a PA6 nylon, preferably containing a filler, for example glass fibre or other fibre fillers. Very preferably, both the cover 5 and the rings 15 are made of plastic material. Also the cup 6 may be made of plastic material, preferably a transparent material, such as for example a polycarbonate.

In a preferred embodiment, the cover 5, the cup 6, and the ring 15, or each ring 15, have on a respective perimeter a plurality of positioning elements for corresponding fixing members, with the aforesaid positioning elements that are distributed in a homologous way on the perimeter of the cover, of the cup, and of the ring or each ring. This characteristic, in addition to guaranteeing a convenient composability of the valve body 1, facilitates the precision of positioning between the various parts, also facilitating the assembly step. For this purpose, the fixing members preferentially comprise threaded members.

In the example illustrated, the aforesaid positioning elements comprise axial seats 5a, 6a and 15a defined on an outer perimeter of the cover 5, of the cup 6, and of the rings 15. In particular, the seats 5a, 6a of the cover 5 and of the cup 6 comprise eyelets projecting substantially at the respective edge where they are fixed to the intermediate part 7, this edge preferably being provided with a flange or coupling seat 5b, 6b; the seats 15a of the rings basically consist of hollow formations, which extend in an axial direction between the upper and lower edges of the peripheral wall of the corresponding ring 15. Preferentially, at least one of the aforesaid edges of the ring 15 is provided with a corresponding flange or coupling seat 15b. Preferentially mounted in the areas of coupling between the various rings 15, as well as between a ring 15 and the cover or the cup, are seal means 15c, for example O-rings.

In one embodiment, such as the one exemplified in Figures 2 and 3, the fixing members comprise a plurality of tie-rod elements 16, each of which is engaged in homologous seats 5a, 6a and 15a of the cover, of the cup, and of each ring. The tie rods may consist of metal bars threaded at least in respective end regions, coupled to which are corresponding nuts, preferably of a self-locking type with washers.

In a preferred embodiment, the valve 1 has means of constraint for constraining movement of the valve member 4 within the cavity 3 of the valve body 2 between the position for closing the valve seat 14 and a pre-defined opening position, where in this pre-defined position the valve member 4 is located by gravity at a maximum distance from the valve seat 14. In this way, the displacements allowed for the valve member 4 can be guided in a substantially determined or circumscribed region of the cavity 3 to ensure a greater reliability of operation.

Preferentially, the aforesaid means of constraint are at least in part integrated in the ring 15 or each ring 15. In the case represented, for example, the aforesaid means of constraint comprise a generally vertical intermediate wall 17 of each ring 15. As may be seen, for example, in Figure 2, in a preferred embodiment the wall 17 extends between generally opposite areas of the peripheral wall 15' of the ring 15, dividing its axial cavity into two parts. As may be seen, in the assembled condition, the various walls 17 are set on top of one another, thereby providing a vertical diaphragm designed to keep the valve member 4 in a substantially pre-defined axial portion of the cavity 3. The correct positioning of the parts is facilitated by the presence of the seats 5a, 6a, 15a and of the corresponding fixing means 16.

In one embodiment, the aforesaid means of constraint comprise at least one supporting element, which projects from a ring 15 towards the inside of the cavity 3 of the valve body 1, where the aforesaid supporting element is able to support the valve member 4 in a position raised with respect to the bottom of the cup 6 and/or of its drain opening 12. In the example illustrated, the aforesaid supporting element comprises a rod 18, having one end configured for engagement with a corresponding engagement seat 19 defined on the inner side of the peripheral wall 15' of the rings 15. The rod 18 may, for example, be made of metal material, for example steel, and possibly be coated with a synthetic sheath 18a, for example a rubber sheath.

In a preferred embodiment, the valve has partition means, for defining within the cavity 3 of the valve body 1 a constrained fluidic path, preferably generally tortuous, between the inlet 8 and the outlet 9. In this way, it is possible to avoid preferential direct paths of the air between the inlet 8 and the outlet 9. This arrangement is particularly advantageous in embodiments, such as the one of Figures 2 and 3, where the inlet and the outlet are both located in the upper part of the valve body 1.

The presence of the aforesaid partition means, in combination with an arrangement of the inlet 8 and outlet 9 of the valve 1 in the upper body part 5 must be understood as in itself constituting an inventive step and thus qualifying for autonomous protection, i.e., independent of an embodiment where the intermediate body part 7 is provided via one or more coupleable components 15 in order to vary the axial dimension of the intermediate part itself.

In one embodiment, the aforesaid partition means comprise a partition, designated as a whole by 20, that divides the cavity 3 into at least two axial half- cavities, designated by 3a and 3b in Figure 3. The partition 20 extends substantially vertically inside the valve body 1, preferably throughout the height of the intermediate body part 7. Very preferably, a respective part of the partition 20 extends also in the region of the cover 5.

In a such an embodiment, as may clearly be appreciated in Figure 3, the valve seat 14 facing the cup 6 - here defined at the end of the outlet 9 - is located in the half-cavity 3b, whereas the inlet 8 opens out into the other half -cavity 3a.

The two half-cavities 3 a and 3b are in fluidic connection preferably only in a lower region of the valve body 2, here in the region of the cup 6: as may be noted, in fact, the lower end of the partition 20 is set at a distance from the bottom of the cup 6. Obviously, the overall dimensions of the buoyant valve member 4 (here the diameter of the sphere) are smaller than the dimensions of passage of the half- cavity 3b where the valve member itself is housed in order to enable an adequate passage of the flow of air. Very advantageously, the partition 20 comprises the intermediate wall 17 of each ring provided.

In the example illustrated, also the cover 5, which is generally shaped like a cap, comprises a respective intermediate part or wall 21. Preferentially, in the assembled condition of the valve 1, the wall 21 is in the position corresponding to that of the intermediate walls 17 of the rings 15: in this way, the half-cavities 3a and 3b are isolated also in the upper part of the valve body 1.

The division made by the partition 20 determines an obligate path for the flow of air drawn in, with an improvement of the fluid-dynamic characteristics of the valve 1 : the incoming air is drawn into the valve body 1 through the connector 10, descends along the half-cavity 3a, and travels in the cup 4, which is without any partition wall. The air then rises along the half-cavity 3b, traverses the connector 11, and proceeds towards the pump P of Figure 1. Obviously, in the case where the sewage is drawn in, the latter would be forced to follow the same path, thereby progressively filling the lower part of the valve body 1 and determining raising of the ball valve member 4. When it reaches a position close to the valve seat 14, the valve member 4 is sucked by the flow of air, thus bringing about correct closing of the valve 1. It will be appreciated that, in the absence of the partition 20, the flow of sewage could be drawn in directly from one connector to the other, reaching the pump.

In a particularly advantageous embodiment, the ring 15, or each ring provided, has a through lateral attachment 22, closed in a sealed way by at least one between a plug 23 a and a transparent body 23b. The transparent body 23b constitutes a level indicator, useful for visual control of the internal part of the valve 1 above the cup 6. If necessary, it is thus possible to install a level indicator also on a number of rings 15. In the case where a ring 15 does not have to be provided with the corresponding level indicator, the corresponding attachment 22 can be closed by a plug 23a. In the example illustrated, the attachment 22 is defined in the peripheral wall 15' of the ring 15 and is preferably provided with a thread. On the other side, the plug 23a and the transparent bodies 23b are provided with a corresponding thread. Plugs and transparent bodies may be made of plastic material, for example a PA6 nylon for the plugs 23a and a polycarbonate for the bodies 23, and preferably associated thereto are corresponding gaskets, for example O-rings.

As may be seen in particular in Figure 3, in one embodiment the cover 5 has two cylindrical seats 24 and 25, which are to receive respective portions of the connectors 10 and 11, here configured as distinct metal parts, for example brass parts.

Preferentially, the connectors 10 and 1 1 have, in the portion for coupling to the lid 5, a respective projecting positioning flange 10a and 11a, which bears upon a corresponding upper area or housing of the cylindrical seats 24 and 25. Underneath the flange 10a, 11a, on the outside of the connectors 10, 11 seal means are provided, for example one or more O-rings, which are to co-operate with the inner surface of the seats 24 and 25. The lower end of the connector 11 preferably projects beyond the corresponding cylindrical seat 25, towards the inside of the valve body 1, and is provided with the valve seat 14. In the example, the seat 14 is formed by a lip ring, preferably made of rubber or the like, fitted on the end of the connector 11. Once again with reference to the example, the coupling portion of the connector 10 is instead substantially contained within the corresponding cylindrical seat 24, without projecting underneath it.

In a preferred embodiment, the upper body part of the valve body comprises a plate 26 for positioning the tubular connectors 10 and 11, which is fixed on the cover 5, for example via metal screws. The plate 26, preferably made of metal, has two holes the diameters of which substantially correspond to, or are a little larger than, those of the connectors 10 and 11, but smaller than those of the corresponding flanges 10a and 11a. In this way, the plate 26 makes it possible to keep the connectors 10 and 11 in position, in any case enabling interchangeability and free rotation thereof so as to facilitate orientation and coupling with the corresponding spiralled hoses (see Figure 1, references HI and H2), which at times are far from flexible.

In one embodiment, advantageously, the positioning plate 26 has a terminal part 26a, which preferably generally projects from the valve body 1 and is configured for providing a fixing bracket. In the example illustrated, the aforesaid terminal part 26a has the free end curved for coupling (for example, via threaded members) with a supporting structure 27, for example fixed to the tank (see also Figure 1).

In a particularly advantageous embodiment, the valve 1 further comprises a lower supporting plate 28, having a first end region configured for coupling to the cup 6 at the drain opening 12 and a second end region configured for providing a fixing bracket. Preferentially, associated to the lower plate 28 is a damper element, having the function of damping any possible vibrations that may be generated during the use of the valve and/or during the displacements of the tanker and providing a soft resting surface for the cup.

In the example, defined in an end region of the plate 28 is a housing passing through the tubular outlet 12a that defines the drain opening 12a of the cup 6. Provided between the two elements is a bushing 29 made of rubber, which forms the aforesaid damper element. Also in this case, the second end region 28a of the plate 28 is curved, for coupling (for example, via threaded members) with a corresponding supporting structure 29, which is, for example, also fixed to the tank (see again Figure 1). Preferentially, both of the plates 26 and 28 have slotted fixing holes for the aforesaid threaded members in order to enable compensation of possible errors of positioning of the corresponding supporting structures 27, 29.

Represented schematically in Figure 4 is a variant embodiment of a safety valve according to the invention. In this figure, the same reference numbers as those appearing in Figures 2 and 3 are used to designate elements that are technically equivalent to the ones described above. The valve 1 of Figure 4 differs from the one illustrated in Figures 2 and 3 as regards the form of the positioning elements 15a of the rings 15, in that they are here shaped like eyelets, as are the homologous elements 5a and 6a of the cover 5 and of the cup 6, respectively. The fixing members, here designated by 116, may comprise screws and nuts. In this embodiment, moreover, both of the edges of the rings 15 are provided with a corresponding flange or coupling seat 15b: such a solution may of course be applied also to the valve of Figures 2 and 3. For the rest, the structure and operation of the valve of Figure 4 is similar to what has already been described above.

Represented schematically in Figures 5 and 6 is a further embodiment of a safety valve according to the invention. Also in these figures the same reference numbers adopted in Figures 2 and 3 are used to designate elements technically equivalent to the ones described above. The valve 1 of Figures 5 and 6 is distinguished by a tangential inlet 8 and by an upper axial outlet 9, in addition to the lower discharge passage provided with the valve 13. In a such a valve, separation of the solid and liquid parts by the flow of air is obtained by exploiting the centrifugal force developed by the swirling motion imposed on the flow of air itself owing to the action of suction of the pump. As a result of the centrifugal force, the particles deposit on the walls of the intermediate part of the valve body 2 and subsequently fall by gravity towards the lower cup 6, here substantially conical, where they collect. Through the purposely provided valve 13, set at the lower end of the lower conical part 6, it is possible to carry out draining of the particles that have been separated. Also in this case, provided inside the valve body 2 are means for constraining the movement of the buoyant valve member within the corresponding cavity of the valve body, between the closing position and a predefined opening position. In such an embodiment, the means of constraint comprise a structure, preferably made of metal, shaped substantially like a basket or a cage, with mesh-like walls, having the function of containment and vertical guide for the ball 4. In Figure 6, this containment and guide structure is designated by 117, with the corresponding buoyant valve member 4 inside. The cage structure 117, which is substantially coaxial to the outlet 9 and to the corresponding valve seat, is preferentially supported by the cover, here designated by 105.

In the valve 1 of Figures 5-6, the cover 105 is traversed by just the outlet 9, defined by a corresponding connector 11, which is here straight. Also in this case, the corresponding positioning plate 26 is provided, which has a single hole for the connector 11.

The intermediate part of the valve body also comprises in this case a plurality of composable rings that can be set on top of one another. In the example represented, two rings 1 15 are provided, substantially like the rings 15 of the embodiments previously described, but without an intermediate wall, as well as a ring 1 15' that has the tangential inlet 8, defined by a corresponding connector 10, possibly made of a single piece with the body of the ring 1 15 ' . Hence, also in the valve 1 of Figures 5 and 6, the capacity of the cavity of the valve body can be varied, by envisaging or not one or more rings 1 15 in addition to the ring 1 15' : the valve can thus include only the cover 105, the ring 1 15', and the cup 6, or else, in addition, one or more rings 115, for a greater capacity of accumulation of liquid.

Preferentially, the axial extension of the cage structure 117 is such as to enable housing thereof in the cavity of the valve body 2 even in the presence of just the ring 1 15' .

As in the embodiments of Figures 2, 3, and 4, in the case where intake of sewage occurs inside the valve body 2, the ball valve member 4 starts to float, gradually approaching the valve seat defined at the internal end of the outlet 9, until it is sucked against the valve seat, thus bringing about closing of the valve 1. As has been said, in this case, the displacements of the valve member 4 are constrained by the cage structure 117.

Illustrated in Figure 7 is a variant embodiment of the valve of Figures 5 and 6, where the same reference numbers are used to designate elements technically similar to the ones already described. In this case, also the tangential inlet 8 is provided directly on the cover here designated by 105', having an axial extension greater than that of Figures 5 and 6. In such an embodiment, then, the valve 1 may include, if need be, just the cover 105a and just the cup 6, or else the cover 105', the cup 6, and one or more rings 1 15. For the rest, operation of the valve of Figure 7 is similar to what has been described with reference to Figures 5 and 6.

Of course, also in the case of the embodiments of Figures 5, 6, and 7 the rings 1 15 and/or the ring 1 15' may be provided with corresponding attachments for plugs and/or level indicators, as for the embodiments of Figures 2, 3, and 4.

The invention finds application in particular in combination with systems for loading and/or unloading tanks for transport/treatment of liquids. It will, however, be appreciated that the valve according to the invention may also be used in other contexts, such as animal-breeding structures and agricultural structures, and systems for distribution and/or accumulation of liquids.

From the foregoing description, the characteristics and advantages of the present invention emerge clearly, amongst which there should be emphasized the simplicity of installation, the low cost of production of the valve, and the possibility of varying in an extremely easy way the height and capacity of the valve.

The advantages of the invention are particularly evident as regards production of large-capacity valves. As compared to the known art, the valve proposed is decidedly less expensive, lighter, and more expandable, with interchangeability and possibility of orientation of the connectors and possibility of installing a number of level indicators on the valve body.

Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary, even significantly, with respect to what has been described and illustrated herein, purely by way of non-limiting example, without thereby departing from the scope of the invention, as defined by the ensuing claims.

As already mentioned, the presence of partition means for defining within the cavity of the valve body a constrained fluidic path between the inlet and the outlet, in combination with an arrangement of the inlet and the outlet both in the upper body part, is to be understood as constituting in itself an inventive step and thus qualifying for autonomous protection, i.e., independent of an embodiment where the intermediate body part is provided via one or more coupleable components in order to vary the axial dimension of the intermediate part itself.