EP1568481A1

EP1568481A1 - Feeder for waste-compacting machines

Info

Publication number: EP1568481A1
Application number: EP05003860A
Authority: EP
Inventors: Alberto Malaspina
Original assignee: VM PRESS Srl
Current assignee: VM PRESS Srl
Priority date: 2004-02-26
Filing date: 2005-02-23
Publication date: 2005-08-31
Also published as: ITTO20040112A1

Abstract

The feeder comprises a hopper (28) having a plane bottom (32) that is lateraly defined by a cove (34), which is internally delimited by a side wall having at least one plane surface, and is aligned to a side outlet connected for feeding material to said machine. A shovel (42) is slidable along the plane bottom at right angles towards the cove (34) under control of first driving means (44), and is provided with a front surface consisting of at least one plane surface. A piston (36) is slidable along the cove (34) to said outlet under control of second driving means (38), and is provided with a polygonal skirt which slidably matches with the cove seat.

Description

The present invention relates to a feeder for waste-compacting machines, particularly for urban solid waste (USW).
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.
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 by means of a screw feeder which draws the material from a hopper. The drum is driven to rotate by steps so that all the cylinders are successively conveyed in front of a squeezing station where a plunger, by penetrating into the cylinder, presses the material contained therein, thereby causing the fluid fraction to be drained through the holes.
As the humid material to be compacted has variable, non-homogenous features, it tends to become stuck when feeding, thereby causing the screw feeder to jam or bridges to form above the screw feeder, so that interventions of the operators are frequently required for restoring the previous feeding conditions.
In order to overcome the above drawback, Italian Patent No. 01308068 discloses a feeder comprising a hopper having a sloping bottom which ends in a semicircular cove, into which a shovel having a symmetrical, semicircular profile, heaps fractions of material to be compacted one after another. A piston, which is axially slidable within the cylindrical area between the cove and the shovel, feeds the separated fraction of material to the perforated cylinders, through an outlet that is aligned to the cove.
The upper edges of the shovel and of the cove are provided with respective blades arranged to cooperate for shearing the material in the hopper, thereby cutting off the fraction of material to feed into the cylinders. However, a drawback of said blades is that they are vulnerable to damage by any rigid bodies enclosed in the material, so that they have to be replaced frequently.
Also, due to the high abrasive power of the material, the cylindrical surfaces of the shovel and of the cove are lined with wear plates which must be periodically replaced. However, the shape of the walls to be lined makes it difficult both to manufacture and to apply such plates, as well as to replace them.
Another drawback of the above, known system is that it is liable to small misalignments, which arise among the matching profiles of the cove, of the pushing shovel and of the feeding piston. These misalignements are caused, for instance, by rigid bodies enclosed in the material which jam between the mutually sliding surfaces.
Therefore, it is a main object of the present invention to provide a feeder for waste-compacting machines which overcomes the drawbacks of the above-described, known feeder.
The above and other objects and advantages of the invention, which will better appear below, are achieved by the feeder having the features recited in claim 1, while the other claims state other advantageous, though secondary features.
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,
Fig. 1 is a side view of a waste-compacting machine comprising a feeding apparatus according to this invention;
Fig. 2 is a cross-section view of the machine of Fig. 1 along line II-II;
Fig. 3 is a cross-section view of the machine of Fig. 1 along line III-III of Fig. 2;
Fig. 4 is a cross-section view of the machine of Fig. 1 along line IV-IV;
Fig. 5 is a view similar to Fig. 2, showing an alternative embodiment of the invention;
Fig. 6 is a view similar to Fig. 3, showing the above alternative embodiment of the invention.
With reference to the above Figures, a waste-compacting machine 10 according to prior Italian Patent No. 01308068 comprises a frame 12 supporting a revolving drum 14 having a horizontal axis A. Drum 14 supports three perforated cylinders 16 having horizontal axes, which are open at their ends and are spaced at equal angles from each other around the axis of the drum. A cylindrical, compaction chamber C is defined within each cylinder.
The drum is driven to rotate by steps by a motor (not shown) in order to cyclically convey one cylinder in front of a feeding duct 18, as described in more detail below, another cylinder in front of a pushing member or plunger 20 which is driven to squeeze the material in the cylinder, thereby causing its fluid fraction to be drained through the holes, and the last cylinder in front of a knock-out piston 22, which is driven to knock the compacted material out from the cylinder. A stationary plate 24 shuts the end of the cylinder on the opposite side with respect to feeding duct 18, while a counter-cylinder 26 shuts the end of the cylinder on the opposite side of plunger 20. A more detailed description of the machine is given in the above prior document.
Machine 10 is provided with a feeder comprising a hopper 28 having a horizontal outlet 30 that is aligned to feeding duct 18 and is connected thereto.
Feeding duct 18 of the feeder according to this invention has a square profile, and hopper 28 has a horizontal plane bottom 32 laterally defined by a cove 34 having a rectangular profile. The cove is aligned to feeding duct 18, and its height H matches with the height of the duct. A feeding pusher member is received in rectangular cove 34, and comprises a piston 36 driven by a hydraulic actuator 38, which piston has a skirt 40 having a square profile which slidably matches with three faces of the cove 34. Piston 36 is aligned to outlet 30 for pushing the material into perforated cylinder 16 through feeding duct 18.
On the opposite side with respect to cove 34, hopper 28 has a opening in which is slidable a shovel 42, which is driven by hydraulic actuators such as 44 for sliding along plane bottom 32 at right angles to piston 36. Shovel 42 has a plane, front surface 46 adapted to engage the open side of cove 34, so that a sliding channel with a square profile is defined for loading piston 38.
Inserts of a hard metal 48, 50 are respectively mounted on the upper edges of shovel 42 and of cove 34. Also, front surface 46 of the shovel, as well as the inner surface of the cove opposing thereto, are lined with respective flat plates 52, 54 which are resistant to wear and are to be periodically replaced.
The above-described feeder operates in synchronism with drum 14 of the machine, one the axis of the drum. A cylindrical, compaction chamber C is defined within each cylinder.
The drum is driven to rotate by steps by a motor (not shown) in order to cyclically convey one cylinder in front of a feeding duct 18, as described in more detail below, another cylinder in front of a pushing member or plunger 20 which is driven to squeeze the material in the cylinder, thereby causing its fluid fraction to be drained through the holes, and the last cylinder in front of a knock-out piston 22, which is driven to knock the compacted material out from the cylinder. A stationary plate 24 shuts the end of the cylinder on the opposite side with respect to feeding duct 18, while a counter-cylinder 26 shuts the end of the cylinder on the opposite side of plunger 20. A more detailed description of the machine is given in the above prior document.
Machine 10 is provided with a feeder comprising a hopper 28 having a horizontal outlet 30 that is aligned to feeding duct 18 and is connected thereto.
Feeding duct 18 of the feeder according to this invention has a square profile, and hopper 28 has a horizontal plane bottom 32 laterally defined by a cove 34 having a rectangular profile. The cove is aligned to feeding duct 18, and its height H matches with the height of the duct. A feeding pusher member is received in rectangular cove 34, and comprises a piston 36 driven by a hydraulic actuator 38, which piston has a skirt 40 having a square profile which slidably matches with three faces of the cove 34. Piston 36 is aligned to outlet 30 for pushing the material into perforated cylinder 16 through feeding duct 18.
On the opposite side with respect to cove 34, hopper 28 has a opening in which is slidable a shovel 42, which is driven by hydraulic actuators such as 44 for sliding along plane bottom 32 at right angles to piston 36. Shovel 42 has a plane, front surface 46 adapted to engage the open side of cove 34, so that a sliding channel with a square profile is defined for loading piston 38.
Inserts of a hard metal 48, 50 are respectively mounted on the upper edges of shovel 42 and of cove 34. Also, front surface 46 of the shovel, as well as the inner surface of the cove opposing thereto, are lined with respective flat plates 52, 54 which are resistant to wear and are to be periodically replaced.
The above-described feeder operates in synchronism with drum 14 of the machine, one cycle being completed for each step of the drum. At the beginning of the cycle, both piston 36 and shovel 42 are withdrawn at their positions shown in Figs. 2, 3. Shovel 42 is then driven to the position shown with dotted lines in Fig. 2. The material lying on the bottom of the hopper is pressed and sheared by the shovel, so that any elongated rigid bodies such as branches, synthetic materials or metals, containers of synthetic material or of metal sheet, and the like, are crumbled, and a partially pressed fraction of the material is heaped in the square channel defined by the cove. To this purpose, hard inserts 48, 50 cooperate like a shear for cutting off the material.
Subsequently, when one perforated cylinder 16 is conveyed in front of feeding duct 18, while shovel 42 is maintained at its position so that it laterally closes the square channel, piston 36 is driven to penetrate into the channel and to push the material contained therein into perforated cylinder 16 through channel 18.
The piston and the shovel are then withdrawn, so that the material above them drops onto the bottom of the hopper for a new cycle, while the drum is driven by one step.
It will be understood by those persons skilled in the art that the square profile of the shovel and of the cove make considerably easier to manufacture and to apply plates resistant to wear 52, 54, and also make the feeder less liable to misalignments. Also, with this arrangement, the shovel and the cove can be provided with inserts 48, 50 having sturdy, sharp edges defined by pairs of orthogonal surfaces.
Referring now to the embodiment of Fig. 5, plane bottom 32 of the hopper ends in a cove 134 having a concave lateral wall consisting of three adjacent, plane surfaces joining at angles of 135° to each other, and is aligned to an outlet having a feeding duct 118 projecting therefrom and having an octagonal profile. A feeding pushing member is received in cove 134 and comprises a piston 136 driven by a hydraulic cylinder 138 and provided with a skirt 140 having an octagonal profile which slidably matches with cove 134.
On the opposite side with respect to cove 134, hopper 28 has an opening in which is slidable a shovel 142, which is driven by respective hydraulic actuators such as 144 for sliding along plane bottom 132 at right angles to piston 136. Shovel 142 has a concave, front surface 146 in mirror symmetry to the side wall of cove 134, which is adapted to engage the open side of the cove, thereby defining an octagonal sliding channel for loading piston 136.
In a way similar to the first embodiment, prismatic inserts of a hard metal 148, 150 are respectively mounted on the upper edges of shovel 142 and of cove 134. In particular, hard insert 148 on shovel 142 has a trapezoidal profile, with an acute angle at the cutting edge of the insert. Also, front surface 146 of the shovel, as well as the inner surface of the cove opposing thereto, are lined with respective flat plates 152, 154 that are resistant to wear and are to be periodically replaced. Also, the inner, upper wall and the inner, lower wall of cove 134 are lined with respective flat, wear plates 156, 158.
In some cases, the above octagonal arrangement allows the perforated cylinders to be fed with optimized effectiveness, for instance, when, due to the composition or morphology of the material, the latter has a lower tendency to expand when conveyed from prismatic feeding duct 18 to cylindrical compaction chamber C.
Two preferred embodiments of the invention have 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

A feeder for waste-processing machines, particularly for urban solid waste, characterized in that it comprises

a hopper having a plane bottom that is laterally defined by a cove which is internally delimited by a side wall having at least one plane surface, and is aligned to a side outlet connected for feeding material to said machine,

a shovel, which is slidable along the plane bottom at right angles to the cove under control of first driving means, and is provided with a front surface consisting of at least one plane surface,

a piston, which is slidable along the cove towards said outlet under control of second driving means, and is provided with a polygonal skirt which slidably matches with the cove seat.
The feeder of claim 1, characterized in that at least one of said side wall of the cove and front surface of the shovel is concave and consists of a plurality of adjacent plane surfaces.
The feeder of claim 1 or 2, characterized in that said at least one of said side wall of the cove and front surface of the shovel has three adjacent, plane surfaces joining at angles of 135° to each other.
The feeder of any of claims 1 to 3, characterized in that said side wall of the cove and front surface of the shovel are in mirror symmetry to each other.
The feeder of any of claims 1 to 4, characterized in that each of said plane surfaces of the side wall of the cove and of the front surface of the shovel is lined with a plate resistant to wear.
The feeder of any of claims 1 to 5, characterized in that an upper edge of the shovel is provided with a hard metal insert.
The feeder of any of claims 1 to 6, characterized in that the upper edge of the cove is provided with a hard metal insert adapted to cooperate with the insert of the shovel.