Title

HIGH CONTAINMENT VALVE, ESPECIALLY ADAPTED FOR INTERCEPTING LOOSE SOLID PRODUCTS TRANSFERRED IN DUCTS.

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Technical field

[0001] The present invention belongs to the technical field of valves and in particular, but not exclusively, to the technical field of valves used to intercept and dose loose solid products, such as powders, granules, pellets, and the like, which are transferred and/or discharged along conduits .

[0002] More specifically, the present invention belongs to the technical field of high-containment or leak-tight valves, i.e., devices that at certain stages of operation are capable of maintaining a pressure differential between upstream and downstream.

[0003] In particular, the present device belongs to the technical field of valves in which the intercepting member comprises a rotor on which a gasket acts.

Present status of the art

[0004] In the field of transferring and intercepting loose solid products, valves are known in which the intercepting member comprises a rotor, usually with a horizontal axis, in which radial compartments are defined, which, progressively during the rotation of the rotor, are filled from above by gravity and emptied downward, again by the force of gravity.

[0005] In known solutions, the outer edges of the rotor define a rotational surface, such as an ellipsoid or a sphere, and the rotor is rotationally housed within a corresponding cavity defined in a valve body that comprises an upper half-body opposed to a lower half-body by the interposition of appropriate static gasket s of elastomeric material .

[ 0006] To reduce the risk of leakage , the outer surface of the rotor is very close to the inner surface defined by the two half-bodies .

[ 0007 ] An opening, usually with a vertical axis , is defined in each half-body for the pas sage of loose product . [ 0008 ] Two half-shaft s protrude horizontally from the rotor along the axis of rotation, which rotationally engage in two corresponding tubular element s , respectively defined in each half-body .

[0009] To achieve a better seal on the rotor half-shaft s , valves are known in which the two half-bodies are opposed to each other according to a surface oblique to the axis of the rotor .

[0010 ] In particular, valves are known that have a lobe rotor in which the perimeter of a first pair of coplanar lobes describes a circumference slightly larger than that described by the perimeter of the other pairs of coplanar lobes , so that at each half-rotation the first pair of lobes slightly interferes with a circumferential gasket that protrudes slightly from the inner surface inside the valve body .

[ 0011 ] Sealing between upstream and downstream of the valve occurs when the larger lobes interfere with and engage the circumferential gasket , thus every half-turn of the rotor, so it is neces sary for the rotation of the rotor to be stopped at exactly one of the two predetermined positions . [ 0012 ] It should be pointed out that in valves of the known type , the circumferential gasket is sub j ect to continuous rubbing, since it is cyclically in forced contact with the edge of the larger pair of lobes , and this cyclic rubbing quickly wears out the ring gasket , with the risk that the loose product may be contaminated with fragment s and particles detached from the elastomeric material with which ring gasket s are usually made .

[ 0013 ] In addition, lobes that do not provide a tight seal present the risk of leakage between one lobe and the other .

Object and summary of the invention

[0014 ] The ob j ect of the present invention is to provide a valve for the interception of loose solid product s that ensures a high seal between upstream and downstream and whose sealing gasket i s not sub j ect to high wear due to cyclic rubbing .

[0015 ] This result is obtained thanks to a valve in which the sealing between the valve body and the rotor is achieved by means of a pneumatic-type ring gasket , which expands to contrast against a corresponding spherical zone def ined on the outer surface of the central portion of an innovative spherical rotor ; inside the latter is defined a plurality of radial compartment s whose axes of symmetry lie in the plane orthogonal to the axis of rotation of the spherical rotor pas sing through the center of the latter .

[ 0016] Diametrically protruding from the central portion of the rotor are two half-shaft s that engage corresponding tubular element s defined in the valve body, to at least one of said half-shaft s are connected appropriate actuating means for rotation and control of the angular position of the rotor .

[0017 ] It should be noted that in the present patent text the term spherical rotor is used to refer to a rotor whose outer surface defines any rotational surface , such as indeed a sphere , but also, for example , an ellipsoid .

[ 0018 ] According to a preferred embodiment the radial compartment s are configured as truncated cones . [ 0019] To ensure the maintenance of the pres sure dif ferential between upstream and downstream of the rotor, the latter is shaped in such a way that on it s outer surface , around each radial compartment , a spherical zone is defined against which the pneumatic gasket expands until it contrast s this spherical zone so as to be seal-tight .

[ 0020 ] The valve body comprises an upper half-body facing and opposing a corresponding lower half-body by the interposition of suitable static gasket s of elastomeric material , an opening for the pas sage of loose product is defined in each half-body, preferably the two openings are coaxial along an axis orthogonal to the axis of the rotor . The pneumatic gasket is housed within a corresponding circumferential s lot defined on the inner surface of one of the two half-bodies , around the opening for the pas sage of loose product .

[ 0021 ] When the rotor is rotating, the pneumatic gasket is deflated and does not interfere with the rotor surface ; when the rotor is stationary, the pneumatic ring gasket is inflated and adheres to the spherical area .

[ 0022 ] For proper operation of the valve , the rotor actuating as sembly must be able to stop the rotation of the rotor so that the axis of one of the compartment s coincides with the axis of the pneumatic gasket .

[ 0023 ] Preferably the pneumatic ring gasket provides the seal between the rotor and the upper half-body through which the loose product enters the valve , or the same gasket could be placed between the rotor and the lower half-body, but if neces sary two pneumatic ring gasket s could also be used, one for each half-body .

[ 0024 ] To improve sealing, the spherical area against which the pneumatic gasket expands should have a good surface finish . [0025] According to a preferred embodiment, in order to improve the sealing performance of the pneumatic ring gasket, it is possible to use scraper rings, partially protruding from corresponding circumferential slots defined in the half-body housing the pneumatic ring gasket, inside and outside the latter, respectively. These scraper rings prevent dust from reaching the spherical zone against which the pneumatic gasket expands, preventing the buildup of loose product resulting in losses of sealing performance.

[0026] Very advantageously, the contact between the two half-bodies is according to a plane oblique to the axis of the rotor, to improve the seal between the half-shafts and the tubular elements in which they are respectively rotationally housed.

Brief description of the drawings

[0027] Fig. 1 shows an overall perspective view of the assembled valve complete with motor.

[0028] Fig. 2. shows a vertical section of the assembled valve according to a plane passing through the axis of the rotor (1) , more precisely according to the A-A plane shown in Fig. 4.

[0029] Fig. 3 shows an enlarged detail of the section shown in Fig. 2, in which the pneumatic gasket (3) is more clearly visible. The gasket (3) is represented deflated and consequently not adhering to the surface of the rotor (1) .

[0030] Fig. 4 shows a top view of the assembled valve complete with motor.

[0031] Fig. 5 shows a perspective view of the rotor (1) in which four compartments are defined (11) .

[0032] Fig. 6 shows a longitudinal section of the rotor (1) •

[0033] Fig. 7 shows a cross section of the rotor (1) , more precisely according to the B-B plane shown in Fig. 6. [0034] Fig. 8 shows an axial view of the rotor (1) . Detailed description of an embodiment of the invention [0035] In the embodiment shown in the figures, the present invention comprises a valve body (2) in which is housed a rotor (1) whose central portion (12) is shaped as a sphere in which radial compartments (11) are defined.

[0036] The valve body (2) comprises an upper half-body (21) and a lower half-body (22) opposed to each other according to a surface oblique to the rotor (1) axis.

[0037] Two horizontal, coaxial half-shafts (13, 14) protrude from the central portion of the rotor, and engage rotationally in corresponding tubular elements defined respectively in each half-body (21, 22) .

[0038] A vertical axis opening is defined in each halfbody (21, 22) for the passage of loose product.

[0039] On the inner surface of the upper half-body (21) , around the opening for the passage of loose product, a circular slot is defined in which a pneumatic ring gasket (3) is housed.

[0040] The radial compartments (11) defined in the central portion (12) of the rotor (1) develop along a respective axis lying on the plane orthogonal to the axis of the rotor (1) passing through the center of the central portion (12) , so that on the outer surface of the latter, around the edge of each of said compartments (11) , a respective spherical zone (15) is defined against which the pneumatic ring gasket (3) expands when the axis of the compartment is coaxial with the axis of the opening for the passage of the loose product.

[0041] The actuation means (4) of the rotor control the angular position of the latter and allow the inflation of the pneumatic gasket (3) only when the axis of a compartment (11) is aligned with the axis of the opening for the passage of loose product; the pneumatic ring gasket (3) is inflated with air or other gas so that it expands to adhere to the spherical area (15) of the rotor (1) . Conversely, while the rotor (1) is rotating, the pneumatic gasket (3) is deflated and does not contact the surface of the rotor (1) .

[0042] To reduce the risk of fouling the area where the pneumatic gasket (3) expands against the rotor (1) , the illustrated embodiment includes two scraper rings (31, 32) concentric to the pneumatic ring gasket (3) on the inside and outside of the latter, respectively. The scraper rings

(31, 32) , like the pneumatic ring gasket (3) also partially protrude from respective perimetrical slots excavated in the inner surface of the upper half-body (21) , coaxial to the opening for the passage of loose product.