Paper-scrap settling and compaction plant

Abstract

 A paper scrap settling and compaction plant comprises a settling chamber with pierced wall (13) contained inside an external shell (14) equipped with an air extraction outlet. Said settling chamber (13) is connected below to a compaction device (12) receiving the settled scrap. Inside said external shell (14) is housed a filtering system for the dust contained in the air which comes out of the pierced-wall settling chamber (13) towards said air extraction outlet.

Description

[0001] The present invention relates to a settling and compaction plant for paper scrap created by the trimming of paper sheets, for example for the production of books and magazines.

[0002] At the present state of the art there are different types of plant in this field. However, each of these plants has a rather great overall space occupied and a certain construction complexity.

[0003] As known, indeed, in the operation of paper scrap plants for settling trimmings it is necessary to provide for filtering of cellulose and kaolin dust which must be separated from the paper scrap and must not be fed into the environment around the plant because it is harmful to the health of the operators. For this purpose it is necessary to place beside the settler a voluminous and cumbersome dust filtering device. In this manner the overall space occupied by the plant is rather great with resulting economic damage for the considerable occupation of space, in addition to the fact that said plants have a certain degree of construction complexity because the settler is connected to the filtering unit by appropriate piping. The settler in turn typically comprises a settling chamber with pierced wall and an added motorized screw feeder for compaction. At the input of the settling chamber is arranged a system of deflectors of the entering flow of air charged with scrap. These deflectors are necessary for directing the air flow in such a manner as to avoid the holes in the walls becoming clogged with scrap with resulting malfunctioning of the overall plant. In addition, the screw-feeder scrap compaction device typically comprises a weighted bulkhead opposite its output opening. This further provision allows having the right degree of compaction of the scrap coming out of the plant but presents a not constant and quite noisy operation. On the other hand, in accordance with the embodiments proposed in the known art, exclusion of the weighted bulkhead involves the necessity of adding another and purposeful compaction device downstream of the plant with considerable increase in the overall cost of the machinery.

[0004] The general purpose of the present invention is to remedy the above-mentioned shortcomings by making available a paper scrap compaction and settling plant which also filters dusts harmful for the health of the operators and having a compact structure with limited total space occupied and which would be simplified at the construction level and hence more economical also.

[0005] In view of this purpose it was sought to provide in accordance with the present invention a paper scrap settling and compaction plant comprising a scrap settling chamber with pierced wall contained inside an external shell equipped with an air extraction outlet with said settling chamber being connected below to a scrap compaction device receiving said settled scrap and characterized in that inside said external shell is housed a filtering system for the dust contained in the air which comes out of the pierced-wall settling chamber towards said air extraction output.

[0006] To clarify the explanation of the innovative principles of the present invention and its advantages compared with the prior art there is described below with the aid of the annexed drawings a possible embodiment thereof by way of non-limiting example applying said principles. In the drawings:

FIG 1 shows a cross section side view of a plant in accordance with the present invention; and

FIG 2 shows diagrammatically a top view of the plant cross-sectioned along plane of cut II-II of FIG 1.

[0007] With reference to the figures, FIG 1 shows a plant in accordance with the present invention comprising a settling device 11 and a scrap compaction device 12. The settling device comprises a pierced-wall settling chamber 13, an external shell 14, an inlet duct for scrap-charged air 15, a plurality of filtering bodies for the dust 16, an extraction plenum 30, a purified-air sucking pump 17 and the funnel for conveyance of the scrap to the compacting device 18.

[0008] The inlet duct 15 connects the paper processing plant (not shown in the figures) producing the scrap to the pierced-wall chamber 13. The air flow charged with scrap in said duct 15 is supported by a purposeful supply pump (not shown in the figures). The chamber 13 is cylindrical in form and has on its side wall a plurality of holes 20 of sizes substantially smaller than the dimensions of the paper scrap. Said holes 20 are designed to let pass dust-filled air (cellulose or kaolin dust for example) but not paper scrap. The chamber 13 can be made for example with a thick-meshed network or with a pierced metal sheet. The conveyance funnel 18 is positioned at the open lower end of the chamber 13 and connects it to the compaction device 12. The external shell receives in its center the chamber 13 and a plurality of dust filters 16 arranged laterally around said chamber 13 (FIG 1 shows three of them by way of example). Said filters 16 can be in the form of filtering sleeves or filtering cartridges. They are connected at their upper ends to the extraction plenum 30 which is located in the upper part of the external shell 14 and is delimited by the separating wall 32. The plenum 30 is connected to a suction pump 17 and communicates with the underlying part of the shell 14 containing the settling chamber 13 only through the filtering bodies 16. The pump 17 at output is connected directly to the external environment. The external shell 14 is also equipped with dust collection means on its lower wall. FIG 1 shows said means in the form of two hoppers 31.

[0009] The compaction device 12 has a horizontal axis and comprises a motor 21, a motion transmission shaft 22, a circular compaction screw feeder 23 and an external shell 24. The motor 21 is connected to the shaft 22 on which is mounted the screw feeder 23. The screw feeder 23 near the output opening 25 has linearly decreasing diameter near said opening. The shell 24 has an inlet opening 26 connecting it to the conveyance tube 18 and a cylindrical symmetry with diameter decreasing near the output opening 25 in the same manner as the diameter of the screw 23.

[0010] FIG 2 shows the settling plant from the top and cross-sectioned along plane of cut II-II of FIG 1. Said FIG 2 shows the external shell 14 containing four filtering bodies 16, the settling chamber 13 in the center and the inlet duct 15. The axis of said inlet duct 15 lies in a horizontal plane and is nearly tangent to its lateral surface opposite the union with the chamber 13. In particular, it is noted that the inlet duct 15 has a right-angle curve 15b near said union with the chamber 13.

[0011] Operation of the above-described plant is discussed below.

[0012] The air charged with paper scrap and dust enters the inlet duct 15. Thanks to the particular curved form 15b near the pierced chamber 13, the air takes on a vortical motion inside the chamber 13 such that the scrap tends to not clog the holes 20 of the chamber wall 13. During the vortical motion the scrap accumulates in the center and falls towards the funnel 18. The dust-charged air however passes through the holes 20 and is sucked by the filters 16 due to the vacuum effect created by the pump 17 inside the extraction plenum 30. Passing through the filters 16, the air loses its dust content. The dust falls downward and is collected in the purposeful dust collection means 31 exemplified in hopper form in FIG 1. In this manner, the pump 17 lets into the environment only air purified of dust.

[0013] The scrap collected in the funnel 18 is conveyed to the compacting device 12. The motor causes rotation of the screw feeder 23 which pushes the scrap towards the outlet opening 25. Thanks to the special shape with decreasing diameter, the scrap is compacted in a continuous flow in this narrowing zone without any weighted bulkhead being necessary to induce compaction.

[0014] It is to be noted that the external shell 14 is made in such a manner as to be openable for maintenance and the filtering bodies 16 are extractable from the machine for cleaning operations.

[0015] In accordance with a preferred embodiment of the present invention the filtered dust is directed to the funnel 18 and then to the compacting device 12 by means of the conveyance wall 33 shown in broken lines in FIG 1. In this manner the dust remains compacted together with the paper scrap and thus avoids having to be removed separately. It is to be noted that this effect was not realizable using filtering device detached from the settling device in accordance with the prior art.

[0016] Following the description the numerous advantages realized with the plant in accordance with the present invention are clear. Indeed, a much more compact plant than those realized previously has been obtained. This was made possible by the advantageous insertion of the dust filters inside the external shell of the settler. In addition to the quite more limited encumbrance, thanks to this contrivance a more economical plant is also realized with saving for example of the costs of piping connecting the settler with the filtering plant. In addition, the plant in accordance with the present invention is also characterized by greater construction simplicity as compared with the prior art. Indeed, thanks to the special curved shape of the inlet duct 15 it has been possible to eliminate the complex of deflectors at the inlet of the pierced-wall chamber 13. These deflectors were necessary for directing the scrap-charged air flow so as to avoid clogging of the holes 20 and this function, in accordance with the instructions of the present invention, is realized by means of the special curved shape of the inlet duct 15. In addition, the final part of the compacting device 12 shaped with decreasing diameter allows elimination of the weighted bulkhead that was necessary for compaction of the scrap. These devices make the plant simpler to construct and as a result more economical.

[0017] Naturally the above description of an embodiment applying the innovative principles of the present invention is given by way of non-limiting example of said principles within the scope of the exclusive right claimed here. For example, indeed, the compacting device could also be with vertical axis and not only with horizontal axis as illustrated above. The filters then would be sized in accordance with the flow of air to be treated and could even completely surround the pierced wall of the settling chamber.

Claims

1. Paper scrap settling and compaction plant comprising a scrap settling chamber with pierced wall (13) contained inside an external shell (14) equipped with an air extraction outlet with said settling chamber (13) being connected below to a scrap compaction device (12) receiving said settled scrap and characterized in that inside said external shell (14) is housed a filtering system for the dust contained in the air which comes out of the pierced-wall of the settling chamber (13) towards said air extraction output.

2. Paper scrap settling and compaction plant in accordance with claim 1 characterized in that said filtering system comprises:

- a suction pump (17) having its output communicating with the outside environment;

- an extraction plenum (30) made inside said external shell (14) above the settling chamber (13) and placed in vacuum relative to the atmosphere surrounding said settling chamber (13) by said pump (17); and

- a plurality of filtering bodies (16) inside said external shell (14), outside of said settling chamber (13) and arranged laterally around the latter and connected with their upper ends to said settling plenum (30) so as to constitute the only way of access to the plenum (30) for the air issuing from the pierced wall of the settling chamber (13).

3. Paper scrap settling and compaction plant in accordance with claim 2 characterized in that said external shell (14) is provided with means for the collection of said dust (31).

4. Paper scrap settling and compaction plant in accordance with claim 3 characterized in that the dust collection means are one or more hoppers (31) made on the lower wall of the external shell (14).

5. Paper scrap settling and compaction plant in accordance with claim 1 characterized in that it includes means (33) of conveyance of the dust from the filtering system towards said scrap compaction device (12).

6. Paper scrap settling and compaction plant in accordance with claim 5 characterized in that the conveyance means include a wall (33) under the filtering system and inclined towards the bottom of the settling chamber.

7. Paper scrap settling and compaction plant in accordance with claim 2 characterized in that the filtering bodies (16) are filtering sleeves.

8. Paper scrap settling and compaction plant in accordance with claim 2 characterized in that the filtering bodies (16) are filtering cartridges.

9. Paper scrap settling and compaction plant in accordance with claim 1 characterized in that the settling chamber (13) is a cylindrical pierced-wall chamber with vertical axis and is fed by an input duct (15) in its upper part.

10. Paper scrap settling and compaction plant in accordance with claim 9 characterized in that said settling chamber (13) is made with a thick mesh network.

11. Paper scrap settling and compaction plant in accordance with claim 9 characterized in that said settling chamber (13) is made with a pierced metal sheet.

12. Paper scrap settling and compaction plant in accordance with claim 9 characterized in that the axis of said input duct (15) opposite the union with the settling chamber (13) is approximately tangent to the cylindrical side surface of the chamber (13) and is contained in a horizontal plane to create a vortical motion of the air inside the chamber (13).

13. Paper scrap settling and compaction plant in accordance with claim 12 characterized in that the input duct (15) has a curve of approximately 90° just before the union with the settling chamber (13) and keeping its axis in a horizontal plane to avoid clogging of the holes (20) of the chamber wall (13) with the paper scrap.

14. Paper scrap settling and compaction plant in accordance with claim 1 characterized in that the compaction device (12) is a powered screw device.

15. Paper scrap settling and compaction plant in accordance with claim 14 characterized in that the powered screw device has a horizontal axis.

16. Paper scrap settling and compaction plant in accordance with claim 14 characterized in that the powered screw device has a vertical axis.

17. Paper scrap settling and compaction plant in accordance with claims 15 or 16 characterized in that said compaction device (12) has a decreasing diameter near the output opening (25) and drawing near thereto to form a narrowing suited to compaction of the scrap.

Drawing