WO2002072339A1

WO2002072339A1 - Apparatus for binding together into pellet-shaped briquets fragmented manufacturing residues, in particular pulverized materials

Info

Publication number: WO2002072339A1
Application number: PCT/IT2001/000122
Authority: WO
Inventors: Luciano Peroni
Original assignee: Co.Ma.Fer. S.P.A.
Priority date: 2001-03-12
Filing date: 2001-03-12
Publication date: 2002-09-19
Also published as: AU2001244539A1; WO2002072339A8

Abstract

It is provided for an apparatus for binding together into pellet-shaped briquets fragmented working residues, comprising a framework (2) showing a catch basin (3) for fragmented working residues, a forming matrix (4) for briquets defining at least a portion of a lateral wall of said catch basin (3), and a plurality of compacting push rods (7) which can move from a recessed rest position in which said push rods (7) are spaced from said matrix (4), to an advanced operating position in which said push rods (7) introduce said residues to be briquetted into extrusion channels (5) of the matrix (4).

Description

APPARATUS FOR BINDING TOGETHER INTO PELLET-SHAPED BRIQUETS FRAGMENTS MANUFACTURING RESIDUES, IN PARTICULAR PULVERIZED MATERIALS

Technical field The object of the present invention is an apparatus for binding together into pellet-shaped briquets fragmented manufacturing residues, in particular pulverized wood materials or other materials. As is known, apparatuses for binding together into briquets fragmented incoherent manufacturing residues, such as wood shavings and sawdust or other pulverized materials, such as for instance paper, leathers or feeds, allow to produce by compacting and pressing said materials, without adding any binder, a cheap fuel with a high calorific value, particu- larly suitable for heating purposes, to be used for instance in small feeders for domestic boilers or in fireplaces. In particular, it is known about briquetting machines provided for the production of small pellet-shaped briquettes or "pellets", for instance with a diameter of about seven milli- meters and with a length varying from few millimeters to about ten millimeters, obtained from a raw material generally consisting of ground and refined wood, i.e. of sawdust with fine and homogenous grains . Said known briquetting machines generally consist of a big bored extrusion roll, for instance with a diameter of 400-500 mm and rotating at 200-400 rpm, showing on its outer portion a very high number of small through holes, for instance having a diameter of 7 mm and spaced of 5-6 mm one from the other .

Within said bored roll two smaller coaxial satellite rolls are arranged, which compress the pulverized raw materials fed by a screw conveyor and push it strongly against the outer portion of the bigger roll, so that it can get into the through holes thus forming pellet-shaped briquets which are then suitably collected and conveyed. In short, said satellite rolls "squeeze" the pulverized materials through the holes of the bigger roll. The surfaces of said rolls should therefore be particularly hard to resists the strong pressures they undergo.

The known method briefly described above shows some important disadvantages .

First of all, the working power required is very high since, because of the strong friction between the satellite rolls and the bigger roll in the full zones between the holes of the latter, a high heat is developed which, beyond resulting in a high energy dissipation, can burn the manufactured briquets . Said briquets can also break into tiny fragments and, therefore, sometimes do not have the desired thickness. Moreover, according to the hardness of the material to be compacted, it may be necessary to replace the extrusion roll of the pellets, thus stopping the production cycle to dismount and mount said roll. In any case, if the hardness of the working residues used as raw material increases, the extrusion roll can slip and overheat. Finally, it should be pointed out that the extraction of the overheated roll from the machine re- sults in difficult and complex dismounting operations. Another complex operation is the cleaning of the large number of holes in the extrusion roll which are blocked by the compacted and partially burnt material, an operation which is generally carried out by drilling said holes. Aims of the invention

In such conditions the technical task underlying the present invention is to provide an apparatus for binding together into pellet-shaped briquets fragmented working residues, which can substantially avoid the aforesaid disadvantages. Within the framework of said technical task an important aim of the invention is to provide an apparatus for binding together into pellet-shaped briquets fragmented working residues, which allows to lower the installed power in a consis- tent way with the same hourly production. Another important aim of the invention is to provide an apparatus which can easily adapt, manually or automatically, to variations in the thickness of the fragmented material used for manufacturing said briquets. A further aim of the. invention is to provide an apparatus which simplifies the operating stages of setup, of elimination of possible obstructions caused by fragmented material and of restart after idle times. Description of the invention The technical task and the aims indicated above are substan- tially reached by an apparatus for binding together into pellet-shaped briquets fragmented working residues, characterized in that it comprises a framework showing a catch basin for collecting the fragmented working residues, a forming ma- trix for briquets provided with a plurality of extrusion through channels and defining at least a portion of a lateral wall of said catch basin and a compacting group consisting of a plurality of compacting push rods which can move from a re- cessed rest position in which said push rods are spaced from said matrix, to an advanced operating position in which said push rods introduce said residues to be briquetted into the extrusion channels of the matrix. Description of the figures In the following two preferred though not exclusive embodiments of an apparatus according to the invention are described, provided as non limiting example and shown in the enclosed drawings, in which:

- Figure 1 shows a longitudinal section of a first embodiment of a main portion of the apparatus according to the invention, in a first operating position:

- Figure 2 shows the apparatus of Figure 1 in a second operating position;

- Figure 3 shows a longitudinal section of a second embodi- ment of said main portion of the apparatus provided with adjustment means and arranged in a first operating position corresponding to the one in Figure 1;

- Figure 4 shows the apparatus of Figure 3 in a second operating position corresponding to the one in Figure 2; - Figure 5 shows the apparatus of Figure 3 in the same operating position as in Figure 4, but with said adjustment means moved to a position of maximum return of the extrusion matrix; - Figure 6 shows a section according to plane VI-VI of Figure 1;

- Figure 7 shows in detail a compacting push rod which can be installed onto a machine according to the invention; - Figure 8 shows a longitudinal section of an execution variant of said main portion of the apparatus, arranged in a first operating position corresponding to the one in Figure 1;

- Figure 9 shows the apparatus of Figure 8 in a second oper- ating position corresponding to the one in Figure 2.

Description of the preferred embodiment

With reference to the figures mentioned above, the apparatus according to the invention is generally indicated with the numeral 1. The enclosed figures only represent the main por- tion of the apparatus, i.e. the extrusion unit. The electromechanical drive unit, the feeding unit for the fragmented material to be compacted and the collection unit for the obtained briquets are not shown in the drawings since they are conventional units known per se. The apparatus 1 comprises a fixed framework 2 showing a catch basin 3 for the fragmented working residues which have to be compacted into small pellet-shaped briquets or "pellets". Said working residues are introduced into the basin 3 by a feeding unit, for instance consisting of a slow horizontal screw conveyor, directly sup- plied by a silo, and of a fast vertical screw conveyor placed above said basin. The latter comprises a first lateral wall 3a at least partially defined by a forming matrix 4 for the briquets, said matrix being provided with a plurality of ex- trusion through channels 5. The compression of the fragmented material within the extrusion channel 5 is carried out by a compacting unit 6 consisting of a plurality of compacting push rods 7, preferably 30 to 100 push rods, which can move between a recessed rest position (shown in Figure 1) in which said push rods 7 are spaced from the matrix 4, and an advanced operating position (shown in Figure 2) in which said push rods introduce the fragmented material to be briquetted into the extrusion channels 5. More precisely, each push rod 7 is arranged coaxially with respect to a corresponding extrusion channel 5 and is moved from said rest position to said operating position by motion means 8. As can be clearly 'seen in Figure 7, each push rod 7 consists of a connection end 7a, a stem 7b having a sufficient section to stand trans- versal forces, and an extrusion portion 7c having such length and section to be introduced into the extrusion channels 5. The passage between said stem 7b and the extrusion portion 7c is preferably rounded. The diameter of the section of the extrusion portion 7c can be for instance of 7 mm. Each push rod 7 is engaged on its connection end 7a with the moving means 8 by means of a support head 9. Said moving means 8, which transmit a reciprocating rectilinear motion to said support head 9, are part of a electro-mechanical drive unit known per se, comprising for instance an electric motor, a belt trans- mission, a crankshaft with flywheel, and a connecting rod linked to the support head 9. Still by way of example, the moving means 8 transmit about 200 complete strokes per minute to the compacting push rods 7. In an execution variant of the first embodiment of the invention said moving means can be hydraulic means. In said solution it is advantageously possible to carry out the apparatus 1 by means of a pair of opposed compacting units 6, 17 sub- stantially moulding the material to be compacted instead of extruding it. In such case the first compacting unit 6 pushes the material from the catch basin 3 into the channels 5, and simultaneously the second compacting group 17, comprising a plurality of secondary push rods 18, shorter than the com- pacting push rods 7, acts with said secondary push rods 18 onto the opposite side of the channels 5, thus substantially moulding the briquets. Now the second compacting unit 17 goes back and the first unit 6 goes further ahead to push the briquets out of the channels 5, then the first unit 6 goes back to its rest position and the compacting cycle is repeated.

Going back to the description of the preferred embodiment, the catch basin 3 comprises a second lateral wall 3b opposite said first wall 3a, showing a plurality of guide channels 10 in which said compacting push rods 7 slide. The guide channels 10 obviously show a greater cross section than the extrusion channels 5, since they house the stem 7b of the compacting push rods 7. In order to make the motion of the support head 9 more precise without exerting transversal stresses onto the compacting push rods 7, guide bars 11 are provided, for instance two of them, which are integral with the framework 2 and parallel to the support columns 13. The support head 9 is mounted with possibility of translation onto said guide bars 11, for instance by means of ball bear- ings 12. The extrusion matrix 4 preferably consists of a plurality of interchangeable plates 4a, which are placed one beside the other and supported by support columns 13 which are part of the framework 2 of the apparatus . Thus the matrix 4 can consist of a variable number of plates and can therefore show extrusion channels 5 whose length and diameter can be adjusted according to production needs. Advantageously, in the second embodiment shown in figures 3, 4 and 5 adjustment means 14 are provided, which can vary and even eliminate, ac- cording to production needs, the penetration into the extrusion channels 5 of the compacting push rods 7 arranged in said advanced operating position. Said adjustment means 14 comprise the matrix 4, which can now move following the direction of the reciprocating rectilinear motion of the com- pacting push rods 7, and control means 15 of said matrix. More precisely, said matrix can be placed in a plurality of positions with respect to said advanced operating position of the compacting push rods. In practice, said matrix 4 comprises an extension 4b slidingly introduced into an opening 3c of the first lateral wall 3a and it is connected to the control means 15, which can move said extension 4b to a plurality of recessed positions with respect to the inner surface of the first lateral wall 3a. The adjustment means 14 can be manually or automatically driven. In case of manual drive the control means can consist for instance of a threaded member, not shown in the figures, integral with the matrix 4 and engaging on a corresponding threaded guide integral with the framework 2. In case of automatic drive said control means 15 can consist for instance of a fluid dynamic cylinder 15. Said fluid dynamic cylinder 15 preferably shows a stem 15a engaged with a stiff casing 16, integral in its turn with the matrix 4 and suitable for conveying downwards the pellets getting out of the extrusion channels 5.

The working of the apparatus described above is the following from a substantially structural point of view. The successive and repeated compressions exerted by the compacting push rods 7 introduce the fragmented material, contained within the catch basin 3 and placed before said push rods, into the extrusion channels 5. The pellets simultaneously carried out within said channels are pushed and moved forward towards the exit of the matrix 4 by the pellets formed successively. The length and thickness of the pellets produced depend both on the ^'thickness and hardness of the fragmented residues used as raw material, and on the length of the extrusion channels of the matrix. The longitudinal size of the latter can be modified by changing the number of plates it consists of or by using plates with a different thickness.

The adjustment means 14 which are used in the second embodiment of the apparatus advantageously allow to carry out various functions both during production setup and after production restart after idle times, and during a standard work cy- cle of the apparatus. In the second case it is indeed possible to interlock the control means 15, which vary the position of the matrix and therefore the penetration depth of the compacting push rods into the extrusion channels, with the current absorption of the motor which transmits a reciprocating rectilinear motion to said compacting push rods. When for instance the pulverized wood material introduced into the catch basin is harder, a higher current absorption takes place and the matrix is therefore moved so as to reduce the penetration of the push rods into said matrix and to keep substantially the same length of the pellets. Vice versa, if the material in the catch basin is softer and therefore better compressible, the position of the extrusion matrix is automatically changed in the opposite direction. The possibility to move the matrix position with respect to the compacting push rods can be used during production setup of the pellets, so as to adjust their size and/or thickness in a suitable way. Moreover, the matrix mobility is particularly advantageous during unblocking operations and especially during restart of the apparatus.

As a matter of fact, after a working period the wood material still present in the extrusion channels tends to solidify forming small crystals with high hardness and compactness. On restarting the apparatus, if it were not possible to move the matrix position, the compacting push rods would not end their stroke since they would be blocked by the presence in the extrusion channels of crystallized material which cannot be moved with the usual installed power. Therefore, the appara- tus would stop the motion of the compacting unit and the apparatus could not be started until the extrusion channels are cleaned. Using the matrix mobility after every working period, the feeding of the catch basin is interrupted and said matrix is moved to stroke end, i.e. moved as much as possible backwards with respect to the inner surface of the lateral wall of the basin above which it is placed, while the action of the compacting push rods 7 goes on until the fragmented material in the basin 3 is over. On restarting the apparatus some cycles of the compacting push rods are first carried out without feeding material into the basin, then the matrix position is recovered and the basin is gradually fed. Thus, no obstructions occur in the extrusion channels and the working of the apparatus is not blocked.

The invention shows important advantages.

First of all, the installed capacity is highly reduced, considering the same production potential, with respect to known methods, since the compacting push roods do not push the fragmented material against full surfaces thus causing enormous pressures and frictions, but compact the material on hollows defined by extrusion channels, where the resistance opposing their reciprocating motion is lower. Moreover, the apparatus allows an easy adjustment of thickness and length of the briquets preventing their overheating or breaking on changing the material used. Finally, the apparatus prevents the formation of obstruction in the extrusion channels where briquetting takes place and simplifies restart operations after production idle times.

Claims

Clai s

1. Apparatus for binding together into pellet-shaped briquets fragmented working residues, in particular pulverized wood materials, characterized in that it comprises: a framework (2) showing a catch basin (3) for fragmented working residues, a forming matrix (4) for briquets provided with a plurality of extrusion through channels (5) and defining at least a portion of a first lateral wall (3a) of said catch basin (3), and at least a compacting group (6) consisting of a plurality

- 'of compacting push rods (7) which can move from a recessed rest position in which said push rods are spaced from said matrix (4), to an advanced operating position in which said push rods introduce said residues to be briquetted into the extrusion channel (5) of the matrix (4).

2. Apparatus according to claim 1, characterized in that each compacting push rod (7) is arranged coaxially with respect to a corresponding extrusion channel (5) , and in that moving means (8) are provided to transmit simultaneously to said push rods (7) a reciprocating rectilinear motion from said recessed rest position and said advanced operating position.

3. Apparatus according to claim 2, characterized in that said catch basin (3) comprises a second lateral wall (3a) op- posite said matrix (4), showing a plurality of guide channels (10) for said compacting push rods (7).

4. Apparatus according to claim 3, characterized in that said moving means (8) comprise a support head (9) with a re- ciprocating rectilinear motion, with which connection ends (7a) of said compacting push rods (7) are engaged, said support head (9) being mounted with possibility of translation on guide bars (11) integral with said framework (2) .

5. Apparatus according to claims 3 or 4, characterized in that each push rod (7) is provided with a stem (7b) sliding within said guide channels (10), and with an extrusion portion (7c) with a smaller section than said stem (7b) and penetrating into said extrusion channels (5) .

6. Apparatus according to any of the claims 1 to 5, characterized in that said matrix (4) comprises a plurality of plates (4a), which are placed one beside the other and can be changed depending on production needs.

7. Apparatus according to any of the claims 1 to 6, charac- terized in that it further comprises adjustment means (14), which can vary, depending on production needs, the penetration into said extrusion channels (5) of said compacting push rods (7) in said advanced operating position.

8. Apparatus according to claim 7, characterized in that said adjustment means (14) comprise: said matrix (4), which can be moved to a plurality of positions following the direction of the motion of said compacting push rods (7) , and control means (15) for the movements of said matrix (4) .

9. Apparatus according to claim 8, characterized in that said matrix comprises an expansion (4a) slidingly introduced into an opening (3c) of the first lateral wall (3a) of the catch basin (3), and in that said control means (15) can move said expansion (4a) of the matrix (4) to a plurality of recessed positions with respect to the inner surface of the first lateral wall (3a) .

10. Apparatus according to claim 8, characterized in that said control means comprise a fluid dynamic cylinder showing a stem (15a) engaged within said matrix (4) .

11. Apparatus according to any of the claims 1 to 6, characterized in that it further comprises a second compacting unit (17) having a plurality of secondary push rods (18) which can move from a recessed rest position in which said secondary push rods (18) are spaced from said matrix (4), and an advanced operating position in which said push rods are introduced into corresponding extrusion channels (5), on the side of said matrix (4) facing said first lateral wall (3a), said secondary push rods (18) cooperating with said compacting push rods (7) to mould said residues to be briquetted, which are introduced into the extrusion channel (5) of the matrix (4) by said compacting push rods (7).