EP2266768B1 - Plant grinder for the production of calibrated wood plates or particles - Google Patents

Abstract

The grinder has a side partition in the form of grids (21a, 21b) whose mesh defines a section of particles, where thickness (e) of the mesh is close to desired length of the particles. Each grid is remote from a cylindrical side wall (4) of a casing for delimiting an annular space outside a disk (12) that emerges into a blower chamber. The disk carries a segment i.e. lower part (2a) and upper part (2b), of a front wall in an angle, and cutters (19, 20) are arranged at center of the angle. The segment covers one of the grids between each grid and the side wall.

Description

The present invention relates to an apparatus for reducing branches of chips, chips or particles whose dimensional qualities are acceptable for a fuel use (domestic or industrial boilers), according to the preamble of claim 1.

Such a plant grinder is known from document D1, FR 2 920 690 A1 .

BACKGROUND OF THE INVENTION

• les appareils à tambour destinés à la découpe ou au déchiquetage des branches de diamètre important, typiquement supérieur à 350 millimètres, (voir WO 9413442 par exemple)
• les appareils à disque pour traiter les branches de diamètre plus petit.

The state of the art in this field consists of two types of equipment:

• drum machines intended for cutting or shredding branches of large diameter, typically greater than 350 millimeters, (see WO 9413442 for example)
• disc machines to treat branches of smaller diameter.

The particles from these machines are of variable size, especially with regard to disk machines.

Indeed, in the latter case, the detached particles of the branch through the disk and are propelled into a discharge chute by a fan which is mainly constituted by fins integral with the rear face of the disk. It is therefore not uncommon for the endings of the branches thus cross the disc without having been cut despite a length much greater than the largest dimension of a chip. These too long particles are not adapted to the destination, as fuel, wood treated and lead to the disqualification of production for this application.

An attempt has been made to remedy this problem by modifying the disk apparatus to add to the fan a sieve which retains the longest particles in the propulsion chamber where the blast fins are shaped into or act as secondary knives. This technique is represented in the document DE 20 2007002423U . It has been found in use an improvement in the homogeneity of the dimensions of the particles at the output of the machine but at the cost of a significant decrease in the ejection power of these particles, the sieve being very quickly clogged and constituting a loss of considerable load to the flow of the air laden with chips.

We will mention at the end the document FR 2 920 690 which describes an apparatus in the housing of which a chipping chamber is limited by the front wall of the housing, by a solid disk housed in the housing and bearing tools embossed on its face facing the front wall so that these tools cross the fixed blade during the rotation of the disk in the housing and a fixed side wall forming a brush against the tools during the rotation of the disk and perforated on at least a portion of its periphery and located at a distance from the side wall of the housing for define between them a particle calibration chamber and a blower chamber containing propulsion fins particles integral with the other side of the disk on the periphery of which opens the calibration chamber.

It has been realized in practice that the final quality of the product does not comply with the calibration requirements because there are still too long wood particles, which could be introduced at an angle into the calibration grid at to reach two to three times the required size.

By the present invention, it has been possible to eliminate this residual defect of the state of the art so that all of the product remains in an acceptable size.

OBJECT OF THE INVENTION

• un carter fermé par une paroi frontale, une paroi de fond et une paroi latérale sensiblement cylindrique, avec, dans la paroi frontale une ouverture d'entrée du bois à traiter bordée d'au moins une lame fixe, et dans la paroi latérale, une ouverture de sortie des plaquettes ou particules,
• un disque plein logé à rotation dans le carter autour d'un axe sensiblement perpendiculaire aux parois frontale et de fond du carter, divisant l'espace intérieur de ce dernier en une chambre de déchiquetage du côté de la paroi frontale et une chambre de soufflerie du côté de la paroi de fond,
• au moins une série de couteaux comprenant des premiers couteaux en relief sur la face du disque tournée vers la paroi frontale de manière que ces couteaux croisent la lame fixe lors de la rotation du disque et un deuxième couteau de reprise fixé au voisinage de la périphérie du disque pour balayer une surface cylindrique centrée sur l'axe de rotation du disque,
• une cloison latérale formant enveloppe du volume balayé par les couteaux lors de la rotation du disque et perforée sur au moins une portion de sa périphérie,

caractérisé en ce que cette cloison latérale est en forme de grille dont la maille définit la section des particules et dont l'épaisseur est voisine de la longueur désirée des particules, cette grille entourant la surface balayée par le deuxième couteau et étant distante de la paroi latérale du carter pour délimiter un espace annulaire débouchant dans la chambre de soufflerie, à l'extérieur du disque et en ce que le disque comporte au moins un segment de paroi périphérique dans l'angle au centre duquel les couteaux d'une série sont contenus et qui coiffe la grille entre cette dernière et la paroi latérale du carter.The subject of the invention is therefore a plant crusher for the production of calibrated wood chips or particles, comprising:

• a casing closed by a front wall, a bottom wall and a substantially cylindrical side wall, with, in the front wall, an entrance opening for the wood to be treated lined with at least one fixed blade, and in the side wall, a exit opening of platelets or particles,
• a solid disc rotatably housed in the housing about an axis substantially perpendicular to the front and bottom walls of the housing, dividing the interior space of the latter into a shredding chamber on the side of the front wall and a blower chamber of the side of the bottom wall,
• at least one series of knives comprising first knives in relief on the face of the disk facing the front wall so that these knives cross the fixed blade during the rotation of the disk and a second knife recovery fixed in the vicinity of the periphery of the disk for scanning a cylindrical surface centered on the axis of rotation of the disk,
• a side wall forming an envelope of the volume swept by the knives during the rotation of the disk and perforated on at least a portion of its periphery,

characterized in that said lateral partition is in the form of a grid whose mesh defines the section of the particles and whose thickness is close to the desired length of the particles, this grid surrounding the surface swept by the second knife and being distant from the wall lateral section of the housing for defining an annular space opening into the blower chamber, outside the disc and in that the disc comprises at least one peripheral wall segment in the angle at the center of which the knives of a series are contained and which cap the grid between the latter and the side wall of the housing.

The fixed grid, the second knife and the segment rotating wall with the disc, constitute the means of calibration of particles from the action of the first knives. Indeed, by the play of the centrifugal forces, the particles detached by the first knives are lodged in the meshes of the grid to abut against the segment and be resized at the passage of the peripheral knife.

The accomplishment of this function is improved by additional features of the mill according to the invention which are due to the constitution of the disc itself.

Thus, the disc has a rear flank to which is fixed the wall segment and a front flank which forms the support of the material to be treated and from which the first knives protrude towards the inlet opening of the housing and in front of the first knives in the direction of rotation of the disk, the front blank being indented from a pocket for collecting formed particles whose peripheral opening faces the aforesaid wall segment. This disk structure can channel the trajectory of most of the chips or particles that have just been detached in the direction of the wall segment, so to constrain the crossing of the gate in front of this segment.

Between the rear flank and the front flank of the disc, the latter has a cylindrical wall of belt, indented at the opening of the pocket, whose radius is less than the radius of action of the second knife, and whose axial dimension is substantially equal to the distance separating the two blanks of the disk increased by the projection of the first knives on the front blank. This feature also makes it possible to prevent the particles from reaching the calibration grid in a zone other than that covered by the segment.

There is also the presence of a shield blade located at the front edge of the wall segment, in the direction of rotation of the disk. This makes it possible to eject the particles which have passed through the gate in the direction of the blower chamber from which they are evacuated by the fins of the disc provided in a manner known for this purpose.

Other features and advantages of the invention will emerge from the description given below of an exemplary embodiment of an apparatus according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 est une vue extérieure du côté frontal de l'appareil selon l'invention dont le panneau de façade frontale est ouvert,
• la figure 2 est une vue en perspective de l'ensemble tournant (disque, couteaux, ailettes) du côté des couteaux,
• la figure 3 est une vue de côté du broyeur de l'invention dans laquelle la paroi latérale du carter a été retirée.

Reference will be made to the appended drawings among which:

• the figure 1 is an external view of the front side of the apparatus according to the invention, the front facade panel is open,
• the figure 2 is a perspective view of the rotating assembly (disc, knives, fins) on the knife side,
• the figure 3 is a side view of the mill of the invention in which the side wall of the housing has been removed.

DETAILED DESCRIPTION OF THE INVENTION

The mill of the invention shown in the figures therefore comprises a casing 1, which comprises, by a front wall, a rear or bottom wall 3 and a substantially cylindrical side or peripheral wall 4. The front wall is provided with an opening 5 comprising here a fixed blade or counter blade 6a substantially horizontal and a fixed blade or against blade 6b substantially vertical. More specifically, it should be noted that in the embodiment shown, the front wall 2 is in two parts a lower part 2a and an upper part 2b, each shaped like a door articulated around a hinge 7. The window 5 is reduced to a cutout 8 of the door 2b with the against blades 6a and 6b carried respectively by the parts 2a and 2b of the front wall.

Through this opening is introduced the end of the branch to reduce chips. This introduction is carried out by means of a charging hopper 8 which is in the motorized case in a known manner. Under the cutting force, this branch tends to stall in the angle formed by the two against blades. The bottom wall 3 of the housing is traversed by a shaft drive shaft 9 and a bearing is provided for this purpose.

The side wall 4 of the housing has an outlet opening 10 located in such a way that the conduit 11 which extends it forms a tube which escapes from the housing tangentially to the wall 4 of the latter. Inside this casing, a disc 12 is rotatably mounted in the direction of the arrow A of the figures, wedged on the axis shaft 9. The diameter of this disc is smaller than that inside the lateral wall 4 of the carter for the reasons that will be explained below.

The disc 12 comprises a rear flank 13, a front blank 14, of smaller diameter than the rear flank, the two blanks being connected by a peripheral belt 15 indented in two places 16 and 17. The width of this belt 15 is such that it is overflowing on the front face of the blank 14.

The front blank has two cutouts 18a and 18b which leave the rear blank uncovered. At the rear edge of each of them, in the direction A of rotation of the disc, the latter carries knives 19, by means of a base 19a fixed by any suitable means between the two blanks of the disk which forms the support of several plates cutting 19b, reported on this base by screws front access. The cutting inserts extend along a substantially spiral curve from the vicinity of the center of the blank 14 of the disc to the periphery thereof. The plane swept by these pads, in front of the front face the blank 14 of a value substantially equal to the projecting thickness of the cutting inserts 19b and the edge of the belt 15 relative to this face, is immediately behind the plane which contains the rear edge of the against blades 6a, 6b. It is understood that the wood introduced into the opening 5 (window) is nibbled (shredded) at each passage of a line of cutting inserts 19b. In order that the entire section of the wood to be treated (the entire surface of the window 5) is swept by the knives, the plates 19b will be arranged so that the surface swept by the cutting edge of one of them overlapping with the surface swept by the cutting edge of the wafer or neighboring wafers. In other words, the circle on which the innermost end of a cutting edge travels is of smaller radius than the circle traversed by the outermost end of the cutting edge of the plate which is adjacent thereto. side of the center of the disc. The disk 12 thus has, in the case illustrated by the attached figures, two lines of cutting inserts 19b. At the end of each of these lines, the base 19a has another knife 20, also in the form of inserts plate, whose attachment to the base is made by radial access screws. The surface swept by the cutting edge of these plates 20 is of intermediate diameter between the diameter of the rear blank 13 and the diameter of the front blank 14. In addition, this diameter is greater than that of the belt 15. The axial dimension of this knife 20 is substantially equal to the distance separating the two blanks 13, 14 of the disk, increased by the projection of the first knives 19 on the front blank, and therefore is equal to the width of the belt 15.

The projection of each plate relative to the front face of the front blank 14 defines the axial dimension (in the direction of the axis 9) of a chipping chamber (nibbling) of the product introduced into the device.

The cutouts 18a and 18b are therefore equipped with knives 19 on their rear edge. The outline of these cuts is connected by the support of the knives and by appropriate partitions to the blank 13 of the disk, so that in the thickness of the disk, it is formed pockets for collecting chips or particles from the cut by the Knives 19. The centrifugal force tends to propel these particles towards the notches 16 and 17 of the belt wall 15

The shredding chamber, which also comprises these two pockets, is delimited at the periphery, inside the cylindrical wall 4, by a grid 21 integral with the inner face of the front wall of the casing 2a 2b.

This grid is, because of this construction of the front wall 2 in two portions: a portion 21a integral with the door panel 2a on its inner face and a portion 21b carried internally by the pivoting panel 2b of the wall 2. It can be seen that this grid 21a, 21b is continuous (21) when the door is closed and is adjacent to the envelope of the volume swept by the knife 20 during the rotation of the disc 12.

The rear flank 13 of the disk 12 carries at the periphery two segments 22a, 22b, of cylindrical wall, facing the peripheral outlet of the pockets, which has an angle at the center inside which the corresponding pocket is located. These segments, which rotate with the disc, extend between the grid 21 and the cylindrical wall 4 of the housing. The distance between the knife 20 and the corresponding wall segment determines the length of the chip housed in a cell or mesh of the grid, therefore the size of a particle size, that is to say its length, which dimension is the most critical because it is the most variable out of the knives, especially at each end of treated branch, when this branch is not more maintained at the entrance to the chipping chamber.

The thickness e of the grid ( figure 1 ) corresponds practically to the aforesaid distance, and therefore to the desired dimension of the particles passing through it. By this means, the particle is held in a radial position against the wall segment and the knife 20 can reduce its size if it is too large. The particle is not likely to be placed at an angle and to cross the grid without being re-cut. Note that the dimension E of the grid, taken in the direction of the axis 9 is substantially equal to the width of the belt 15 so that there can not be too much space between this grid and the blank 13 disc in which could pass unordered wood particles.

Each wall segment 22a, 22b is equipped on its front edge with a shield blade 23 which scans the annular volume between the outer periphery of the grid 21a, 21b and the cylindrical wall 4 of the housing. This blade 23 has a slope that tends to repel the particles that have passed through the grid on the side of the rear face of the blank 13 in a blower space 24, defined by the rear face of the blank 13, the bottom wall 3 and the wall 4 of the casing 1 which, in known manner, is equipped with ventilation blades 25 belonging to the blank 13.

The flow of air generated by these blades 25 enters the blower chamber exits this chamber through the outlet opening 10 by driving the wood particles that come from the shredding chamber through the grid 21a and 21b. It is understood that the air flow is not hindered by any obstacle such as a comb or sieve, the calibration of the particles having been performed upstream of the creation of this pneumatic particle transport stream.

In operation, the wood introduced through the window 5 is reduced to particles by the tools 19b in the shredding chamber. Their path is controlled by the grid 21a and 21b so that they can be calibrated effectively upstream of their pneumatic extraction.

Among the advantages of the invention, besides optimizing its operation (maximum efficiency for a given energy expenditure), mention will be made of the ease with which the maintenance and repairs of the active part of the mill can be carried out. Indeed, the presence of the front door 2b gives access to all the plates 19b and 20 to change without further disassembly of the device.

It is the same if it is necessary to intervene on the against blades 6a and 6b. It will be noted finally that in the mill according to the invention the grid 21a and 21b is removably attached to the housing 2 so that the user can remove it. He then has an ordinary mill that he can use for the sole purpose of a reduction of a plant material without calibration constraints. The mill of the invention can thus be used more cost-effectively.

Claims (4)

1. A plant grinder for producing calibrated chips or particles of wood, the grinder comprising:

   a casing (1) closed by a front wall (2a, 2b), by a rear wall (3), and by a substantially cylindrical side wall (4), with an inlet opening (5) in the front wall to admit wood for treatment bordered by at least one stationary blade (6a, 6b), and an outlet opening (10) in the side wall (4) for discharging chips or particles;

   a solid disk (12) received in the casing to rotate about an axis (9) substantially perpendicular to the front wall (2a, 2b) and the rear wall (3) of the casing, thereby subdividing the space inside the casing into a chipper chamber beside the front wall (2a, 2b) and a blower chamber beside the rear wall (3);

   at least one series of cutters (19, 20) comprising first cutters (19b) projecting from the face of the disk (12) that faces towards the front wall (2) so that said cutters cross the stationary blade (6a, 6b) during rotation of the disk (12), and a takeup second cutter (20) fastened in the vicinity of the periphery of the disk (12) to sweep a cylindrical surface centered on the axis of rotation (X) of the disk; and

   a side wall (21a, 21b) adjacent to the envelope of the volume swept by the cutters (19, 20) during rotation of the disk and perforated over at least a portion of its periphery;

   characterized in that said side wall is in the form of a grid (21a, 21b) of mesh that defines the section of the particles and of thickness (e) that is close to the length desired for the particles, said grid surrounding the surface swept by the second cutter (20) and being spaced apart from the side wall (4) of the casing to define an annular space on the outside of the disk (12) that opens out into the blower chamber, and in that the disk includes at least one segment (22a, 22b) of the peripheral wall that subtends an angle at the center within which the cutters (19, 20) of a series are contained and that covers the grid (21a, 21b) between the grid and the side wall (4) of the casing.
2. A plant grinder for producing calibrated chips or particles of wood according to claim 1, characterized in that the disk (12) possesses a rear sheet (13) to which the wall segment (22a, 22b) is fastened and a front sheet (14) from which the first cutters (19) project towards the inlet opening (5) of the casing (1), and in that the front sheet (14) is notched ahead of the first cutters (19) in the direction of rotation (A) of the disk (12) with a pouch (18a, 18b) for recovering particles that are formed, the peripheral opening (16, 17) thereof facing the above-mentioned wall segment (22a, 22b).
3. A plant grinder for producing calibrated chips or particles of wood according to claim 2, characterized in that, between the rear sheet (13) and the front sheet (14) of the disk (12), the disk includes a cylindrical surrounding wall (15) that has notches (16, 17) level with the opening of each pouch (18a, 18b), that is of radius that is less than the action radius of the second cutter (20), and that is of axial size that is substantially equal to the distance between the two sheets of the disk plus the distance by which the first cutters project from the front sheet.
4. A plant grinder for producing calibrated chips or particles of wood according to claim 3, characterized in that the disk (12) is fitted with a shield blade (23) situated level with the front edge of the wall segment (22) in the direction of rotation (A) of the disk.

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