FIELD OF THE INVENTION

The present invention refers to a pinch valve, in particular pneumatically or mechanically actuated.

The pinch valve according to the present invention has an innovative outer profile aimed at optimising the pneumatic closing action of the valve and the elastic opening return, and an innovative inner profile that ensures, for the same passage port, that the closing stroke of the valve itself is minimised, thus reducing the opening and closing times thereof and reducing the structural stresses of the valve itself.

BACKGROUND

Currently pinch valves, in particular pneumatically or mechanically actuated ones, are known which are generally used for blocking and adjusting abrasive, corrosive and fibrous products. Pinch valves are used increasingly frequently as blocking and adjustment valves for emulsions, liquid mortar, powders, gaseous substances, compressed air, dust, granulates, pellets and so on.

The introduction of compressed air or a liquid into the housing chamber of the pneumatic pinch valve, causes the closure of the sleeve, which is highly elastic. Alternatively, a mechanical device, exerting an adequate pressure towards the centre of the valve, allows the complete closure thereof. The reopening of the sleeve therefore takes place thanks to the elasticity of the material of which it consists and to the configuration of the sleeve itself.

The structure of the body of the sleeve ensures a free lip-shaped closure of the sleeve.

Thus it is ensured that there is an absolutely fluid- tight interruption of the flow of product and simultaneously the maximum lifetime of the sleeve.

Therefore, the pneumatic or mechanical pinch valve closes and provides a tight seal of the flow of product .

As soon as the introduction of compressed air/liquid into the housing chamber of the pneumatic pinch valve is interrupted, and the chamber is vented or emptied, the sleeve, through its rebound elasticity/return force and with the pressure of the medium, opens for complete passage .

The advantages of pneumatically or mechanically- actuated pinch valves are in particular the free sliding of the product, a minimal friction resistance, tight closure without losses, the absence of problems of obstruction, low weight and cost-effectiveness of manufacture .

Despite the good general operation of pinch valves of the type considered here, known pinch valves of the state of the art suffer from some problems, in particular when it is wished to make valves adapted for supporting a large number of opening/closing cycles, with quick closing and opening times and with low manufacturing costs .

SUMMARY OF THE INVENTION

The purpose of the present invention is to avoid the drawbacks that known solutions of the state of the art suffer from, by providing a pneumatically or mechanically-actuated pinch valve that makes it possible to optimise the seal of the valve itself, optimising the distribution of the pressure force exerted by the fluid or by the mechanical device on the sleeve itself.

Furthermore, a purpose of the present invention is to provide a pinch valve that, for the same passage port, makes it possible to minimise the closing stroke of the valve, thus reducing the opening and closing times thereof .

Last but not least, a purpose of the present invention is to provide a pinch valve that allows the correct positioning of the valve itself in its housing, thus ensuring the correct division of the forces, in the sleeve closing step.

These and other purposes according to the present invention are accomplished by a pinch valve according to claim 1.

Further characteristics of the apparatus according to the present invention are the object of the dependent claims .

In general, the pinch valve according to the present invention comprises a hollow substantially cylindrical main body comprising a longitudinal axis, comprising, at at least one of the ends of said cylindrical body having longitudinal extension, a portion defining at least one abutment surface that extends on a plane substantially perpendicular to the longitudinal axis of said cylindrical main body, characterised in that it comprises, on said main body, at least one narrowing area, one or more ribs being provided to connect the areas of said main body upstream and downstream of said narrowing area, and in that said main body internally comprises a longitudinal axial opening having substantially elliptical profile defined by the union of two opposite arcs of circumference, the central segment of each of said arcs of circumference having a substantially radial rib extending from it, which connects said arc of circumference to the inner surface of the main body.

LIST OF FIGURES

The characteristics and advantages of the pinch valve according to the present invention will become clearer from the following detailed description, given as an example and not for limiting purposes, referring to the attached schematic drawings, in which:

figure 1 is a perspective view of the pinch valve according to the present invention;

- figure 2 is a front view of the pinch valve according to the present invention;

- figure 3 is a side view of the pinch valve according to the present invention;

- figure 4 is a view from above of the valve of figure 3;

- figure 5 is a section view with a transverse plane of the pinch valve according to the present invention. DE TAILED DESCRIPTION OF THE INVENTION

With reference to the attached figures, the pinch valve 1 according to the present invention comprises a hollow substantially cylindrical main body 10 extending mainly longitudinally .

Said main body 10 thus defines a longitudinal axis, and internally comprises an axial opening 20 also having mainly longitudinal extension.

Said main body 10 also comprises, at at least one of the ends 11 of said cylindrical body 10, a portion defining an outer abutment surface 11a that faces towards the outside of said cylindrical main body 10 and an inner abutment surface lib that faces towards the inside of said body 10, said ends 11 and said surfaces 11a, lib extending on a plane substantially perpendicular to the longitudinal axis of said cylindrical main body 10.

The pinch valve 1 according to the present invention also comprises, on said main body 10, at least one narrowing area 13, preferably central with respect to the longitudinal extension of said main body 10.

Preferably, and according to the preferred embodiment shown in the attached figures, said narrowing area preferably consists of two opposite tapered portions 13a, 13b, preferably with conical geometry, substantially at the central area of the main body 10. At said central narrowing area 13 there is therefore the portion of smaller diameter of said tapered portions 13a and 13b with conical geometry.

More preferably, on said main body 10 there will be, starting from each end 11, a first cylindrical segment 10a, 10b from which said tapered portions with conical geometry 13a and 13b respectively extend.

One or more ribs 14 are provided to connect the cylindrical areas 10a, 10b of said main body 10 upstream and downstream of said narrowing area 13. Such ribs 14 are arranged along the longitudinal direction and, as can be seen in particular in figures 4 and 5, have a tapered cross section towards the centre of the main body 10, at said narrowing area 13, with joining areas 15a, 15b.

With particular reference to the section of figure 5, defined by a transverse plane perpendicular to the longitudinal axis and passing through the central narrowing area 13, said main body 10 internally comprises a longitudinal axial opening 20 having a substantially elliptical inner transversal profile 21 defined by the union of two opposite arcs of circumference 21a, 21b, the central segment of each of said arcs of circumference 21a, 21b being directly joined to said ribs 14, in particular indicated in figure 5 with 14a, 14b respectively, which therefore extend radially from said arcs of circumference 21a, 21b.

The ribs 14 allow an optimal distribution of the pressure or mechanical forces necessary to close the valve, and at the same time optimise the elastic return during opening.

In the same way, the particular conical geometry of the tapered areas 13a, 13b optimises the opening and closing strokes of the valve itself, thereby resulting in greater reactivity of the valve.

Again with reference to figure 5, it can be seen how in the preferred embodiment of the pinch valve according to the present invention, shown as an example and not for limiting purposes, on a transversal section plane said arcs of circumference 21a, 21b have the respective ends extending until they touch the inner surface 10a of said main body 10.

Thanks to this particular configuration of the inner rib portions 22a, 22b that connect the arcs of circumference 21a, 21b that form the profile 21 of said longitudinal axial opening 20 to the inner surface 10a of said main body 10, the mechanical behaviour of the pinch valve according to the present invention is optimized.

In the case of use of pneumatic management, the closing pressure force F _p that acts on the outer surface of the main body 10 acts according to the direction of the arrow F _p indicated in figure 5, and is equally divided by the symmetrical geometry of the profile 21.

On the other hand, in the case of use with a mechanical device, the direction of the force F _m will be perpendicular to the ribs 14, for reference again see figure 5, where the forces F _p and F _m are shown at the same time only as an example.

The particular elliptical geometry of the transversal profile 21, made by the union of two arcs of circumference 21a, 21b makes it possible, whilst keeping the passage flow rate unchanged, to reduce the closing stroke of the pinch, allowing a greater activation speed and, thanks to the smaller stroke, less deformations of the material, consequently extending the lifetime of the membrane itself.

The design of the pinch valve 1 according to the present invention is not therefore symmetrical on the transverse plane, and it is therefore important that the sleeve is correctly positioned in its seat.

In order to ensure that the valve 1 is correctly positioned in its seat, on at least one of said end portions 11 an abutment plane 23 is advantageously provided, for example defined by a bevel according to what is visible in figure 1, which will have a corresponding abutment element in said seat.

The pinch valve 1 thus conceived, preferably made with elastomeric materials or other suitable materials according to what is known to those skilled in the art, can undergo numerous modifications and variants, all of which are covered by the scope of protection of the invention as defined by its claims.

Moreover, all of the details can be replaced by technically equivalent elements. In practice, the materials used, as well as the sizes, can be whatever according to the technical requirements.