A Butterfly Valve for Plants for Granular and/or Powder Materials.

Technical Field

The invention relates to a butterfly valve for plants for granular and/or powder materials.

Butterfly valves typically comprise an annular main body, provided at ends thereof with two flanges. By means of the flanges, the main body can be connected either to an opening of a container (generally a silo) through which the material enters or exits, or to two conduits such that a single conduit is constituted for transporting the material, of which the main body substantially forms an intermediate portion. The annular body delimits internally thereof a seating in which a flat circular obturator is rotatable about a transversal axis with respect to the seating. The obturator is rotatable between a closed position, in which it is substantially coaxial to the seating and occludes the seating of the valve, preventing the transit of the material, and at least an open position, in which the axis of the obturator is inclined with respect to the axis of the seating and the seating of the valve is at least partially open to the passage of material. The rotation axis of the obturator is identified by a pair of pivots which are constrained to the obturator in diametrically opposite positions. The pivots are rotatably housed internally of holes afforded through the lateral wall of the main body of the valve. Support brackets, externally associated to the lateral wall of the main body, are provided with holes, coaxial to holes afforded through the lateral wall of the main body of the valve, which define further housings for the pivots of the obturator. At least one of the

pivots is provided with a free end which can be constrained to an actuator of rotary motion which commands rotation of the obturator. Background Art

In known-type butterfly valves, both the flanges for the valve connections and the support brackets for the pivots of the obturator are constrained unremovably to the main body. Typically all the components are welded to one another, or may even be made in a single piece. This means that for different special connection geometries of the valve to a further element, or for each special form of connection flange, constructionally different butterfly valves have to be realised. Further, in a case in which, for the most various reasons, it were necessary to change the geometry of the connecting flanges of the valve, this would require a total change of the valve. The same drawback would be manifested in a case of replacement of the support bracket of the obturator pivot.

The aim of the present invention is to provide a butterfly valve which overcomes the drawbacks of the valves of known type, and in particular a valve which offers a modular constructional concept which can be adapted to different needs with only a limited number of overall modifications of the valve.

An advantage that the valve of the invention exhibits is that it enables greater fluency of the material which crosses it and limits the onset of play between the obturator and the valve seating. Disclosure of Invention

Further characteristics and advantages of the valve will better appear from the detailed description made herein below with reference to the accompanying figures of the drawings, given by way of non-limiting example, in which:

figure 1 is a perspective partially-exploded view of the valve of the present invention, in a first embodiment thereof; figure 2 is a perspective view of the valve of the present invention in a second embodiment thereof; figure 3 is a partial second view of the valve of figure 1;

With reference to the figures of the drawings, the butterfly valve 1 of the present invention comprises an annular main body 2, provided with a longitudinal axis x. The main body 2, at ends thereof, is provided with a first ring 3 and a second ring 4. The rings 3, 4 extend radially, distancing from the longitudinal axis x on approximately-perpendicular planes with respect to the longitudinal axis x. The rings 3, 4 can have the function of flanges by means of which the main body 2 can be connected to a further element. To this end the rings 3, 4 exhibit a plurality of through-holes 30,

40 by means of which, with bolts, the rings 3, 4 can be connected with the flanges of other elements.

The annular body 2 internally delimits a seating 5 which, preferably, develops circularly about the longitudinal axis x. The seating 5 is substantially defined by a cylindrical surface which delimits an open channel through which the materials crossing the valve flow.

An obturator 6 is rotatable internally of the seating 5 about a transversal axis y which is perpendicular with respect to the longitudinal axis x and is arranged diametrically with respect to the seating 5.

The obturator 6 is rotatable between a closed position, in which it occludes the channel delimited by the seating 5, and at least an open position, in which it does not occlude the channel. When the obturator 6 is in the closed position, the projection of the surface of the obturator 6 on a perpendicular plane to the longitudinal axis x completely occupies the projection of the seating 5 on the same plane. In this way the channel delimited by the

seating 5 is closed and prevents transit of material through the main body 2. When the obturator 6 rotates into a different position with respect to the closed position, the projection of the surface of the obturator 6 on a perpendicular plane to the longitudinal axis x is reduced in size and does not completely occupy the projection of the seating on the same plane. In these conditions at least a portion of the channel delimited by the seating 5 is open to the passage of material through the main body 2. The obturator 6 can substantially take on two main conformations. In a first conformation, illustrated in figure 2, the obturator 6 is circular and flat and exhibits a diameter that substantially coincides with the diameter of the seating 5, except for a small amount of play which is necessary in order to permit the rotation of the obturator 6. In this conformation the closed position of the obturator is defined when the obturator 6 is arranged on a perpendicular plane to the longitudinal axis x, such as to occlude the channel delimited by the seating 5. In order to obtain a secure closure of the channel delimited by the seating 5, in the closed position the obturator 6 has to be in contact with the seating 5 itself and thus the diameter of the obturator 6 has to be more or less the same as the diameter of the seating 5. This leads to scraping between the external edge of the obturator 6 and the seating 5 which can cut the surface of the seating 5 (and/or the external edge of the obturator 6), compromising the seal of the obturator 6. In order to obviate this drawback, in an embodiment of the valve the diameter of the obturator 6 is smaller than the diameter of the seating 5 by an amount which is sufficient to ensure that in the closed position of the obturator 6 a canal forms between the external edge of the obturator 6 and the surface of the seating 5. A seal 7, preferably made of a flexible material, can be interposed between the surface of the seating 5 and the external edge of the obturator 6 such as to occupy the above-mentioned canal. The seal 7 is

preferably shaped as a cylindrical sleeve which, at an end, is provided with a radial ring 7a; it is however often advantageous to provide the seal of a further raid ring (not illustrated by of the same type as the ring 7a) arranged at the other end of the sleeve. The seal 7 is predisposed to be positioned in contact with the seating 5 coaxially of the longitudinal axis x, with the radial ring 7a (or radial rings) thereof positioned in contact with the first or second ring 3, 4 of the main bodies 2 (or both in the case of a presence of two radial rings). The presence of the seal 7 guarantees a safe closure of the canal delimited by the seating 5, when the obturator 6 is in the closed position, obviating the drawbacks connected to the scraping between the seating and the obturator 6.

In a second conformation, illustrated in figures 1 and 3, the obturator 6 is not circular but oval or elliptical. In this conformation the obturator 6 is provided with a larger axis and a smaller axis. The smaller axis coincides with the transversal axis y about which the obturator rotates and is about as long as the diameter of the seating 5. The larger axis is perpendicular to the smaller axis and exhibits a greater length than the diameter of the seating 5. In the closed position the obturator 6 obviously cannot be arranged in a perpendicular position with respect to the longitudinal axis x, but is arranged in an inclined position such that the projection of the greater axis on a perpendicular plane to the longitudinal axis x coincides with the diameter of the seating 5. The peripheral development of the obturator 6 is such that in the closed position of the obturator 6 the external edge of the obturator 6 is arranged entirely in contact with the seating 5 in order to ensure a complete closure of the canal delimited by the seating 5. This conformation of the obturator 6 considerably limits the scraping between the edge of the obturator 6 and the seating 5. Any play that might be created between the seating 5 and the obturator 6 might also be

compensated for in the closed position with a greater inclination of the obturator 6 with respect to the longitudinal axis x. In this case too it is however possible to arrange a seal 7 such as the one described herein above.

In both the conformations of the obturator 6, the transversal axis y of rotation of the obturator is identified by a pair of pivots 8, 9 which are constrained to the obturator 6 in diametrically opposite positions. The pivots are housed rotatably internally of the holes 80, 90 afforded through the wall of the seating 5. Two support brackets 10, 11 are associated to the lateral wall of the main body between the two rings 3,4. These support brackets 10, 11 are each provided with a hole 81, 91, coaxial to one of the holes 80, 90 afforded through the wall of the seating 5, which defines a further housing for one of the rotating pivots 8, 9 of the obturator 6. A first pivot 8 is thus supported by a first hole 80 of the seating 5 and a first support bracket 10. A second pivot 9 is supported by a second hole 90 of the seating 5 and a second support bracket 11. At least the first pivot 8 is provided with a free end 8a which projects with respect to the first support bracket 10 and is predisposed to connect to an actuator of rotary motion (not illustrated) suitable for causing a rotation of the obturator 6. Preferably the two support brackets 10, 11 are associated to the main body 2 with removable constraints, for example bolts. In this way the brackets can easily be replaced, with no need to substitute the main body 2. The butterfly valve 1 further comprises at least a flange 12 removably associated to the main body 2. The flange comprises a first portion 12a and a second portion 12b predisposed to be rigidly joined to one another. Each of the portions comprises a main surface 13a, 13b predisposed to be superposed on the first 3 or the second ring 4. In the figures, the main surfaces 13 a, 13b are superposed on the first ring 3 and reference will be

made to this arrangement from now on for reasons of clarity. The main surfaces 13 a, 13b exhibit semicircular edges 14a, 14b which, when the two portions 12a, 12b of the flange are joined, also conjoin to one another, delimiting a circular opening 14a, 14b. The circular opening, when the flange is associated to the main body 2, is arranged coaxially of the seating 5. The main surfaces 13 a, 13b are further provided with a plurality of holes and/or slots 50 for connection, by means of bolts, of the flange 12a, 12b to the flange of a conduit.

The first portion 12a of the flange 12 comprises a first and a second shaped appendage 15a, 16a. The shaped appendages are arranged radially at the ends of the curved edge 14a and extend about perpendicularly with respect to the main surface 13 a. A first cut 17a, extending in a distancing direction from the curved edge 14a, partially separates the first shaped appendage 15a from the main surface 13a at the zone in which they are joined together. In the same way a second cut 18a, extending in a distancing direction from the curved edge 14a, partially separates the second shaped appendage 16a from the main surface 13a at the zone where they are joined together.

The first and the second cuts are predisposed to be positioned between the first ring 3 and the second ring 4 of the main body 2. In the example illustrated in the figures of the drawings, in which the flange 12 is arranged on the side of the first ring 3, the cuts 17a, 18a are slotted over the first ring 3. In this position the first ring 3 is retained by the cuts 17a, 18a such that the main body 2 and the first portion 12a of the flange 12 and cannot be respectively displaced in a parallel direction to the longitudinal axis x. Similarly to the first portion 12a of the flange 12, the second portion 12b comprises a first and a second shaped appendage 15b, 16b. The shaped appendages are arranged radially at the ends of the curved edge 14b and

extend about perpendicularly with respect to the main surface 13b. A first cut 17b ₅ extending in a distancing direction from the curved edge 14b, partially separates the first shaped appendage 15b from the main surface 13b at the zone in which they are joined together. In the same way a second cut 18b, extending in a distancing direction from the curved edge 14b, partially separates the second shaped appendage 16b from the main surface 13b at the zone in which they are joined together.

Similarly to the first portion 12a of the flange 12, the first and the second cuts of the second portion 12b are predisposed to be positioned between the first or the second ring 3, 4 of the main body 2. In the example illustrated in the figures, in which the flange 12 is arranged at the side of the first ring 3, the cuts 17b, 18b are slotted over first ring 3. In this position the first ring 3 is retained by the cuts 17b, 18b such that the main body 2 and the second portion 12b of the flange 12 cannot be subjected to relative displacements in a parallel direction to the longitudinal axis x.

The connection of the flange 12 to the main body 2 of the valve is obtained by arranged the first and the second portions 12a, 12b with the respective cuts 17a, 18a, 17b, 18b between the first or the second ring 3, 4. In these positions, as illustrated in the figures, the main surfaces 13 a, 13b of the two portions 12a, 12b of the flange are coplanar and supeiposed on the first ring 3. The semicircular edges 14a, 14b conjoin, delimiting a circular opening 14a, 14b which is arranged coaxially to the seating 5 such as not to obstruct the canal delimited by the seating 5. The two portions 12a, 12b of the flange 12 are in reciprocal contact at the shaped appendages 15a, 16a, 15b, 16b thereof. At the shaped appendages, the two portions 12a, 12b can be rigidly constrained to one another by means of bolts or other components such as to constitute the flange 12. The flange 12 is constrained to the main body 2 with respect to direct movements parallel to the longitudinal

axis x by means of the engagement between the first ring 3 and the cuts 17a, 18a, 17b, 18b of the two main portions of the flange 12. The flange 12, which up to now has been described in combination with the first ring 3, can naturally be associated to the second ring 4 entirely similarly, such that two flanges 12 can be associated to the first and second ring at the same time.

The possibility of de-assembling the flange 12 into the two portions 12a, 12b offers the possibility of separating the flange 12 with respect to the main body 2 of the valve. This enables, for a same model of main body 2, a plurality of flanges 12, all different, that can be used for connecting a same main body 2 to various elements in turn provided with different flanges. In this way, during the production stage, the realisation of the main body 2 can be differentiated, and can follow a relatively standardised production process, from the realisation of the flange 12 which, being constructionally very simple, can be conformed in a potentially unlimited number of variants. The union of the main body 2 and the flange 12 can be done absolutely flexibly at the end of respective production cycles. The separability of the various components of the valve of the present invention enables a considerable simplification of the production processes and a reduction in costs: the main body 2, the first and the second flange 12 portion, and also the first and the second support bracket 10,11, can be obtained by very simple working process, and possibly without the need for welding. The plastic seal can be obtained using known techniques, such as moulding, dropping into a form, extrusion, etc. All of these working methods are particularly simple and economical. The modularity of the valve of the present invention further helps to prevent the use of welding for connecting up the parts to one another. In any case, for particular needs, it is possible to connect the various components to each other by means of

welding. Connection by means of welding is also considerably simplified thanks to the advantageous configuration of the components of the valve.