Waste-compacting machine

Abstract

 In this machine a plunger (36) is guided to slide along a support (B) for penetrating into a coaxial, adjacent, cylindrical chamber (C) provided with holes, through an axial end of the chamber, and for squeezing wastes in the chamber, thereby causing a fluid fraction of the wastes to be drained through the holes. A screen (30) is arranged adjacent to the insertion end and is provided with an opening (H) which is coaxial to the plunger (36) and supports a steel ring (R) along its perimeter, which ring is adapted to surround the plunger. The screen separates the cylindrical chamber (C) from an external area (V) at ambient pressure.

Description

[0001] The present invention relates to an improvement in a waste-compacting machine, particularly for urban solid waste.

[0002] Machines are known which compact urban solid waste by pressing it under very high pressure, thereby causing its humid fraction, which can be recycled for production of fertilizers, to be separated from the dry fraction, which can be recycled as fuel.

[0003] In particular, for an increased productivity, a waste-compacting machine is known which comprises three perforated cylinders supported on a revolving drum and arranged to be cyclically filled with the material to be compacted. The drum is driven to rotate by steps so that all the cylinders are successively conveyed in front of a plunger, which penetrates into the cylinder and squeezes the material contained therein, thereby causing the fluid fraction to be drained through the holes.

[0004] The plunger is guided to slide within a bush which is also suited to seal the corresponding end of the cylinder.

[0005] However, the drained fluid has a high abrasive power, mainly in consideration of the very high pressures reached during squeezing, so that the leaks between the plunger and the bush cause the latter to progressively wear, thereby affecting the matching accuracy between the bush and the plunger with risk of jamming, particularly when rigid parts get stuck in the annular area between the cylinder and the plunger.

[0006] Therefore, a main object of the present invention is to provide a waste-compacting machines, in which the material is pressed in a cylinder by a plunger guided to slide within a bush, which is improved so that the bush is shielded from the abrasive action of the fluid fraction of the material to be compacted.

[0007] The above and other objects and advantages of the invention, which will better appear below, are achieved by a waste-compacting machine having the features recited in claim 1, while the other claims state other advantageous, though secondary features.

[0008] The invention will be now described in more detail with reference to a preferred, non-exclusive embodiment, shown by way of non-limiting example in the attached drawings, wherein:

Fig. 1 is a side view of the waste-compacting machine according to this invention;

Fig. 2 is a plan view of the machine of Fig. 1;

Fig. 3 is a diagrammatical cross-section view along line III-III of Fig. 2 of a portion of the machine according to the invention;

Fig. 4 is a diagrammatical, cross-section view along line IV-IV of Fig. 2 of a portion of the machine according to the invention;

Fig. 5 is a diagrammatical, cross-section view along line V-V of Fig. 2 of a portion of the machine according to the invention;

Fig. 6 is a view to an enlarged scale of a detail of Fig. 4.

[0009] With reference to the above Figures, a waste-compacting machine 10 comprises a stationary frame 12 which pivotally supports a drum 14 having a horizontal axis A (Fig. 4).

[0010] Drum 14 supports three cylinders 16 which are open at their ends and also have horizontal axes. The cylinders are spaced at equal angles from each other around the axis A of the drum, and are provided with a plurality of radial holes 18. A cylindrical chamber C is defined within each cylinder for receiving the material to be compacted therein.

[0011] A loading station 20, a squeezing station 22 and an unloading station 24 are arranged in front of the drum and are angularly spaced from each other around the axis A, correspondingly to cylinders 16. The drum is driven to rotate by steps by a motor (not shown), in order to cyclically convey one cylinder in front of the loading station, another cylinder in front of the squeezing station, and the last cylinder in front of the unloading station.

[0012] In a way known per se, loading station 20 comprises a screw feeder 26, or any other suitable feeding device such as, e.g., a pressing member, which is coaxial to cylinder 16 when the latter is positioned in front of the loading station, and is driven to rotate for conveying the material from a hopper 28 to the cylinder.

[0013] A screen 30 integral with stationary frame 12 is arranged in front of the base of drum 14 on the side of hopper 28, and is provided with three openings which are aligned to cylinders 16 when they are positioned in front of stations 20, 22, 24. A wall 32 integral with stationary frame 12 is arranged in front of the opposite base of the drum, and is provided with two openings which are aligned to those cylinders 16 which are positioned in front of squeezing station 22 and unloading station 24. On the contrary, wall 32 shuts the end of that cylinder which is arranged in front of loading station 20.

[0014] Squeezing station 22 comprises an auxiliary piston 34, which is coaxial to the cylinder positioned in front of such station and sealingly closes one of its ends, as well as a plunger 36 that is operable to penetrate into cylinder 16 through the other end, thereby causing the material contained therein to be squeezed and the humid fraction to be drained through holes 18. Plunger 36 is guided to slide within a bush B integral with stationary frame 12, and is driven by a hydraulic cylinder 38 supported on the frame.

[0015] According to this invention, a ring R made of a wearproof steel is supported along the perimeter of that opening H of screen 30 which is cut in front of squeezing station 22. The ring is larger in diameter than plunger 36, so that an annular gap L is defined between the plunger and the ring when the latter is engaged by the plunger.

[0016] An annular chamber V is defined along the axial span between bush B and ring R, and is in fluid communication with a draining channel S leading to a collecting reservoir 39 for the drained fluids.

[0017] In a way known per se, the unloading station comprises a knockout piston 40 which is coaxial to that cylinder positioned in front of such station, and is operable to penetrate cylinder 16 under control of a hydraulic actuator 42 for knocking the compacted material out through that opening cut in the wall on the opposite side with respect to the piston. The knocked-out material is unloaded onto a chute 43 for removal.

[0018] The operation of the improved machine substantially corresponds to the operation of the above-cited, known machine. The drum is driven to rotate by steps of 120° for cyclically subjecting each cylinder to:

• a loading step, in which a part of the material in hopper 28 is conveyed into the cylinder aligned to the loading station by screw feeder 26 or pressing member,
• a squeezing step, in which the squeezing member consisting of plunger 36 penetrates into that cylinder aligned to the squeezing station and causes the material contained therein to be squeezed, against auxiliary piston 34, the fluid fraction being drained through the holes in the cylinder,
• an unloading step, in which knockout piston 40 penetrates through one end of the cylinder aligned to the unloading station and pushes the compacted material out through the opposite end.

[0019] During squeezing, a part of the fluid fraction of the material to be compacted, which part is not drained through the holes in the cylinders, is drained into annular chamber V, which is at ambient pressure, through annular gap L between the plunger and the ring, and then into draining channel S and into collecting reservoir 39.

[0020] It can be seen that the fluid fraction which, in absence of ring R and annular chamber V, would be drained through the plunger and the bush, thereby causing the latter to progressively wear, in the improved machine according to this invention is in fact drained similarly to the main fraction which is drained through the holes in the cylinder. Accordingly, the bush is sheltered from the wear and the effectiveness of the draining action of the machine is improved.

[0021] A preferred embodiment of the invention has been described herein, but of course many changes may be made by a person skilled in the art, depending on the circumstances, within the scope of the inventive concept.

Claims

1. A waste-compacting machine, comprising a plunger (36) guided to slide along at least one support (B) for penetrating into a coaxial, adjacent, cylindrical chamber (C) provided with holes, through an axial end of the chamber, and for squeezing wastes in the chamber, thereby causing a fluid fraction of the wastes to be drained through the holes, characterized in that a screen (30) is arranged adjacent to said axial end and is provided with an opening (H) which is coaxial to the plunger (36) and supports a steel ring (R) along its perimeter, which ring is adapted to surround the plunger, said screen separating the cylindrical chamber (C) from an external area (V) at ambient pressure.

2. The waste-compacting machine of claim 1, characterized in that the inner diameter of said ring (R) is larger than the diameter of the plunger (36), so that an annular gap (L) is defined between the plunger and the ring when the latter is engaged by the plunger (36).

3. A waste-compacting machine, comprising

- a stationary frame (12),

- a drum (14) which is pivotally supported with horizontal axis (A) on said stationary frame (12),

- at least two cylinders (16) which are open at their ends, are supported with horizontal axes on the drum, are spaced at equal angles from each other around the axis (A) of the drum, and are each provided with a plurality of radial holes (18),

- a loading station (20) adapted to feed material into one cylinder,

- a squeezing station (22) comprising a plunger (36) which is slidingly supported within a bush (B) integral with the stationary frame (12), for penetrating into the cylinder (16) through one inlet, axial end thereof, thereby causing the material contained therein to be squeezed and its humid fraction to be drained through the holes (18),

- an unloading station (24) adapted to knock the compacted material out from the cylinder through one outlet end thereof,

- a screen (30) which is integral with the stationary frame (12), is arranged adjacent to said inlet, axial end, and is provided with an opening (H) coaxial to the plunger (36),

- shutting means arranged to shut said outlet axial end when the cylinder is positioned in front of the squeezing station,

said loading station, squeezing station and unloading station being spaced from each other about the axis (A) correspondingly to the cylinders (16), and said drum being driven to rotate by steps for cyclically conveying one first cylinder in front of the loading station, one second cylinder in front of the squeezing station, and one third cylinder in front of the unloading station,
characterized in that it comprises a steel ring (R) supported along the perimeter of the opening (H) for surrounding the plunger, and in that said screen separates the cylindrical chamber (C) from an external area (V) at ambient pressure.

4. The machine of claim 3, characterized in that the inner diameter of said ring (R) is larger than the diameter of the plunger (36), so that an annular gap (L) is defined between the plunger and the ring when the latter is engaged by the plunger (36).

Drawing