SCREENING MACHINE FOR SCREENING SOLID MATERIAL

Abstract

Screening machine (10) for screening solid materials, comprising a screening box (12) shaped so as to have a plurality of perimeter walls (16, 17, 19, 21), an upper wall (15) and an opposite bottom wall (13), in order to make said solid materials to be screened flow inside it. Said screening machine (10) comprises at least one active anti-propagation device (24) integral with said screening box (12).

Claims

1. Screening machine (10) for screening solid materials, comprising a screening box (12) shaped so as to have a plurality of perimeter walls (16, 17, 19, 21), an upper wall (15) and an opposite bottom wall (13), in order to make said solid materials to be screened flow inside it, wherein said screening box (12) comprises at least one explosion anti-propagation device (24) of the active type, which is integral with said screening box (12), and wherein said at least one anti-propagation device (24) comprises at least one pipe (28) provided with a plurality of delivery nozzles (29) for delivering an extinguishing chemical substance in fluidic communication with one or more compartments (23) of said screening box (12) and at least one chemical suppressor (30) for containing said extinguishing chemical substance in fluidic communication with said pipe (28).

2. Screening machine (10) as in claim 1, wherein said at least one pipe (28) is attached to at least one of said perimeter walls (16, 17, 19, 21) of said screening box (12).

3. Screening machine (10) as in claim 1, wherein said at least one chemical suppressor (30) is attached to said upper wall (15) of said screening box (12).

4. Screening machine (10) as in any claim 1, wherein said at least one pipe (28) comprises segments (28a, 28b, 28c, 28d) dedicated to each of the delivery nozzles (29).

5. Screening machine (10) as in any claim 1, wherein said at least one pipe (28) is disposed inside said screening box (12), attached to an internal surface of at least one of said perimeter walls (16, 17, 19, 21).

6. Screening machine (10) as in claim from 1, wherein said at least one pipe (28) is disposed outside said screening box (12), attached to an external surface of at least one of said perimeter walls (16, 17, 19, 21).

7. Screening machine (10) as in claim 1, wherein said screening box (12) comprises a plurality of anti-propagation devices (24) provided with a plurality of said chemical suppressors (30) equipped with respective pipes (28).

8. Screening machine (10) as in claim 7, wherein said anti-propagation devices (24) are positioned in proximity to lateral walls (16, 17) of said opposite perimeter walls (16, 17, 19, 21) of said screening box (12).

9. Screening machine (10) as in claim 1, wherein said at least one pipe (28) is disposed along at least one of said lateral walls (16, 17), and wherein said delivery nozzles (29) are disposed at different heights.

10. Screening machine (10) as in claim 1, wherein each of said delivery nozzles (29) is disposed between two screening surfaces (25) or between one screening surface (25) and said upper (15) or bottom (13) wall.

11. Screening machine (10) as in claim 7, wherein said chemical suppressors (30) are positioned in an array on said upper wall (15).

12. Screening machine (10) as in claim 11, wherein said screening box (12) comprises a first row (F1) of chemical suppressors (30) positioned in proximity to a first one of said lateral walls (16, 17), and a second row (F2) of chemical suppressors (30) positioned in proximity to a second one of said lateral walls (17, 16).

13. Screening machine (10) as in claim 2, wherein said at least one chemical suppressor (30) is attached to said upper wall (15) of said screening box (12).

14. Screening machine (10) as in claim 8, wherein said chemical suppressors (30) are positioned in an array on said upper wall (15).

Description

DESCRIPTION OF THE DRAWINGS

[0031] These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

[0032] FIG. 1 is a lateral view of a screening machine for screening solid materials according to the present invention;

[0033] FIG. 2 is a plan view of the present screening machine;

[0034] FIG. 3 is a partial three-dimensional view of the machine of FIGS. 1-2;

[0035] FIG. 4 is a section view and on a larger scale of a part of a screening machine according to a variant, in which an anti-propagation device can be seen disposed inside the screening box;

[0036] We must clarify that in the present description the phraseology and terminology used, such as for example the terms horizontal, vertical, front, rear, upper, lower, internal and external, with their declinations, have the sole function of better illustrating the present invention with reference to the attached drawings and must not be in any way used to limit the scope of the invention itself, or the field of protection defined by the attached claims.

[0037] Before describing an embodiment of the present invention, we must also clarify that this must not be considered as limited in its application to the details of the construction and disposition of the components as described in the present description using the attached drawings. In fact, the present invention can take on other embodiments and can be obtained or executed in various other equivalent ways.

[0038] To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications.

DESCRIPTION OF SOME EMBODIMENTS OF THE PRESENT INVENTION

[0039] With reference to FIGS. from 1 to 4, a screening machine 10 according to the present invention for screening solid materials, in particular of the type which could give rise to potentially explosive dusts, such as for example small wood shavings, although it is not limited to this, comprises a support structure 11 on which there is mounted a screening box 12 which is configured to make the solid materials to be screened flow inside it.

[0040] The screening box 12 substantially has the shape of a parallelepiped with a rectangular base and comprises a bottom wall 13, an upper wall 15 and four perimeter walls, in particular two lateral walls 16 and 17, a front wall 19, which is associated with an inlet compartment 20, or hopper, for the entry of the materials to be screened, and a rear wall 21 associated with a series of outlet ducts 22, which are used for the collection of the screened materials, possibly divided according to granulometry.

[0041] In the screening box 12 there are some compartments 23, divided into at least a lower compartment 23a and an upper compartment 23b, in which there are disposed screening surfaces 25 on which the solid materials to be screened can flow.

[0042] The screening box 12 has an inclination of a few degrees, for example from 1? to 45? with respect to a horizontal plane, so that the screening surfaces 25 are higher in the part that is close to the inlet compartment 20, in order to promote the displacement of the materials to be screened toward the outlet ducts 22.

[0043] The screening box 12 is mounted on the support structure 11 by means of elastic joints 18 so that it can oscillate.

[0044] On the support structure 11 there is installed a movement device 26 of a type known per se, which is connected to the screening box 12 in such a way as to give the latter an oscillatory movement such as to make the solid materials flow from the inlet compartment 20 to the outlet ducts 22.

[0045] The screening machine 10 is equipped with at least one anti-propagation device 24, advantageously of the active type, that is, capable of suppressing a possible explosion that were to occur in the screening box 12, for example caused by a sudden ignition, caused by self-combustion of the solid materials to be screened, when first ignited, detected by suitable sensors, through the injection of an extinguishing chemical agent.

[0046] Each anti-propagation device 24 comprises at least one pipe 28 provided with a plurality of delivery nozzles 29 for delivering an extinguishing chemical substance in fluidic communication with one or more of the compartments 23 of the screening box 12, and at least one chemical suppressor 30 for containing the extinguishing chemical substance, which is attached, in the example described here, to the upper wall 15 of the screening box 12, and which is in fluidic communication with the pipe 28. The chemical suppressor 30 can be, for example, a fire extinguisher attached to the upper wall 15 by means of attachment means 31, for example clamps or other systems of a known type, and which is connected to the pipe 28 by means of a suitable connector 32.

[0047] However, it is not excluded that the chemical suppressor(s) 30 of the anti-propagation devices 24 can also be associated with other walls, different from the upper wall 15, for example with the bottom wall 13 or with the lateral walls 16 and 17.

[0048] The pipe 28, preferably but not necessarily rigid, can be attached to one or both lateral walls 16 and 17 of the screening box 12 depending on the installation configuration chosen for the anti-propagation devices 24.

[0049] The lateral walls 16 and 17 can be provided with apertures 33, which allow access to the compartments 23 for the delivery of the extinguishing chemical substance through the delivery nozzles 29. The apertures 33 could also be replaced by holes made in the lateral walls 16 and 17 in correspondence with the delivery nozzles 29.

[0050] The delivery of the extinguishing chemical substance by the chemical suppressor 30 through the delivery nozzles 29 can occur automatically. In this case, suitable sensors 34 are installed inside the compartments 23 which are configured to detect the triggering of an explosion or a fire, and to send an activation signal at least to the delivery nozzles 29 that are responsible for that zone, for example a given compartment 23, or to the control unit thereof, if present.

[0051] Preferably, the pipe 28 comprises a plurality of delivery nozzles 29 for the delivery of the extinguishing chemical substance for each compartment 23 of the screening box 12. In this way, it is possible to protect both the lower compartment 23a and also the upper compartment 23b with maximum coverage.

[0052] The pipe 28 can be divided into segments 28a, 28b, 28c and 28d dedicated to each of the delivery nozzles 29, see in particular FIG. 4. These segments 28a, 28b, 28v, 28d are separate and independent.

[0053] The pipe 28 can be integrated inside the screening box 12, therefore be disposed on an internal surface of the lateral wall 16, 17 to which it is attached, see in particular FIG. 4. The solution according to which the pipe 28 is associated with an internal surface of the lateral wall 16, 17 guarantees greater reliability and lower impact of the installation of the anti-propagation device 24 on the screening box 12.

[0054] The pipe 28 could, however, also be positioned outside the screening box 12, therefore on an external surface of the lateral wall 16, 17 to which it is attached, as shown in FIGS. 1-3. The solution in which the pipe 28 is attached to an external surface of the lateral walls 16, 17 of the screening box 12 allows a more immediate access thereto, if replacement or maintenance interventions are required.

[0055] Alternatively or in combination with the above, the pipe 28 can be attached to the upper wall 15.

[0056] The screening machine 10 can comprise a plurality of anti-propagation devices 24 provided with a plurality of chemical suppressors 30 equipped with respective pipes 28, see for example FIGS. 1-3.

[0057] For example, it is possible to provide anti-propagation devices 24 positioned in proximity to both the opposite lateral walls 16 and 17 of the screening box 12, so as to deliver the extinguishing chemical substance from both sides of a given compartment 23.

[0058] The chemical suppressors 30 can be positioned in an array on the upper wall 15 of the screening box 12. For example, it is possible to provide a first row F1 of chemical suppressors 30 positioned in proximity to the lateral wall 16, and a second row F2 of chemical suppressors 30 positioned in proximity to the opposite lateral wall 17. The two rows F1 and F2 are schematically shown in FIG. 1 and each comprise, for example, three chemical suppressors 30.

[0059] The number and position of the chemical suppressors 30 with respective pipes 28 and delivery nozzles 29 can be chosen in such a way as to suitably cover the entire volume of the compartments 23 of the screening box 12 with the extinguishing jet, since in each compartment 23 an explosive atmosphere of wood dust-air can be generated between one screening surface 25 and the other.

[0060] In particular, the delivery nozzles 29 are advantageously disposed at different heights along the lateral walls 16 and 17 of the screening box 12, so as to cover all the compartments 23 in a uniform manner.

[0061] Furthermore, each of the delivery nozzles 29 of a same anti-propagation device 24 can be disposed between two screening surfaces 25, see FIG. 4. Other embodiments of the present invention provide that, in addition or alternatively, on the front wall 19 and/or on the rear wall 21, other anti-propagation devices 24 can be installed with the respective pipes 28 associated with the walls, internally and/or externally, so that the delivery nozzles 29 are directed toward both compartments 23 of the screening box 12.

[0062] It is clear that modifications and/or additions of parts may be made to the screening machine 10 as described heretofore, without departing from the field and scope of the present invention as defined by the claims.

[0063] In the following claims, the sole purpose of the references in brackets is to facilitate reading and they must not be considered as restrictive factors with regard to the field of protection claimed in the specific claims.