FR2962922A1 - PELLETING MACHINE WITH IMPROVED LUBRICATION AND COOLING MEANS - Google Patents

Abstract

Machine for producing granules from a material, by pressure, of the type comprising: - a central shaft; - a compression chamber; - At least one compression roller mounted free rotation on a secondary shaft in the chamber and whose periphery is in contact with the inner wall of the latter; means for rotating the chamber, the secondary shaft or both; - Lubricating means of the rotating elements capable of discharging the used lubricant out of the machine; characterized in that it comprises means of circulation said "return": - able to allow at least a portion of the used lubricant, to circulate inside the machine, before evacuation out of it; and - constituting means for cooling the lubricant circulating in the machine.

Description

PELLET MACHINE WITH IMPROVED LUBRICATION AND COOLING MEANS

The present invention relates to a machine for producing granules by pressing various pulverulent materials, such as wood chips or food products.

The granules are made using such machines by compression and extrusion of the powder material between a fixed element and at least one rotating element Io. More particularly, the material is crushed between at least one compression roll and the wall of a compression chamber, forming a die, and having holes on its periphery to form the granules.

The at least one compression roll is mounted within the cylinder-shaped compression chamber. Generally, there is provided at least two compression rollers whose periphery bears against the inner wall of the chamber. The chamber and the rollers are mounted on respective shafts, uprights or arms, which may be on the one hand either horizontal or vertical, and on the other hand either fixed or rotated. The granules are evacuated at the lower part of the chamber periphery.

In any type of machine, the rollers are freely rotatably mounted on a common shaft or arm, either directly or via a shaft each. The invention can be applied to all these types of pelletizing machines.

FIGS. 1 to 8 (which will be described in more detail later) show the possible configurations by distinguishing the machines according to whether the rotated shaft is vertical (FIGS. 1 to 4) or horizontal (FIGS. 5 to 8).

Figures 1 and 2 show machines said vertical shaft where the chamber is fixed and the rollers are mounted on a horizontal common shaft itself rotated by a vertical shaft.

Figures 3 and 4 show machines with vertical shaft where: - the chamber is rotated according to a vertical shaft and constitutes a rotor; the rollers are mounted for free rotation on a fixed horizontal common shaft.

Figures 5 and 6 show machines with horizontal shaft in which: - the chamber is rotated according to a horizontal shaft and constitutes a rotor; Io - the rollers are mounted for free rotation on two respective arms themselves connected to a fixed horizontal support arm.

Figures 7 and 8 show machines with horizontal shaft where the chamber is fixed and the rollers are mounted free rotation on two respective horizontal shafts themselves connected to a horizontal shaft rotated.

Whatever their type, pellet machines raise two major problems, namely lubrication on the one hand and cooling on the other.

Lubrication is necessary to reduce wear on the rotating parts. In this respect, French Patent No. 2,863,184 has proposed lubricating means in which the used lubricant is removed from the machine. The used lubricant therefore does not come into contact with the powdery materials to be treated, unlike the prior art in which the used lubricant was previously mixed with the granules produced, which of course adversely affects the quality and hygiene of the granules produced. and what prohibits this means for certain applications of the "food" type except to use a food lubricant, expensive and less efficient.

This known device is entirely satisfactory with regard to lubrication.

Moreover, the other difficulty mentioned above relates to the cooling of these machines which is necessary, particularly in view of the extrusion phenomenon and the compression of the treated materials. This difficulty leads to limitations in the operation of such machines in terms of efficiency, time and maintenance costs, taking into account the interventions required to repair or change wear parts.

In known manner, it has been attempted to overcome this difficulty by injecting grease continuously to the rotating parts. However, the cooling achieved is not sufficient and the phenomenon of rolling of the fat participates in the heating of the rotating parts.

The need is therefore felt for a pelletizing machine which has adequate means of lubrication and which is adequately cooled in order to allow optimal use in terms of efficiency, and to avoid or reduce the frequency of repair or change operations. wear parts. The present invention provides such a machine.

To this end, according to the invention, the machine for producing granules from a material, by pressure, of the type comprising: a central shaft; - A compression chamber, mounted either fixed or rotated on said central shaft, and whose outer wall is a die for extruding the material; at least one compression roller mounted freely rotatable on an arm or secondary shaft, in the chamber and whose periphery is in contact with the inner wall of the latter; means for rotating the chamber, the secondary shaft or both; - Lubricating means of the rotating elements, comprising lubricant circuits 30, able to remove the used lubricant out of the machine; is characterized in that it comprises means of circulation said "return" able to allow at least a portion of the used lubricant to circulate inside the machine, before evacuation out of it. Thus, said "return" means of the used lubricant inside the machine constitute cooling means for the latter.

The fluid has coolant properties, in addition to its lubricating properties.

More specifically, the passage of used lubricant in the machine, before evacuation out of it, is located at least partly in said central shaft provided for this purpose with a central recess. Advantageously, the machine is of the type in which the central shaft is fixed.

Preferably, to ensure optimum cooling, the entire length of the fixed central shaft is used for the passage and return of used lubricant. The lubricating means comprise two "forward" lubricant supply circuits, namely: a first circuit opening in the vicinity of the support means of the central shaft, such as bearings; A second circuit passing through said central shaft, and one end of which opens into the compression roll or rolls.

The lubricating means further comprise a lubricant recovery tank that has been used, connected to filtering means and cleaning the lubricant. These means are associated with means for regulating and measuring the flow rate, the latter being themselves connected to each of the said "feed" regenerated lubricant feed circuits.

"The way" goes to contact with the bearing (s) - or landing (s). The "return" begins at the point of entry of the fluid into the bearing (s) - or bearing (s). It is from this point that the fluid begins to implement its heat transfer fluid properties by storing the calories produced at the point (s) the hottest (s) of the machine.

The invention will be better understood in the light of the following description of illustrative but nonlimiting examples of the invention with reference to the accompanying drawings in which: FIGS. 1 to 4 are schematic diagrams of granulating machines, say to vertical tree; - Figures 5 to 8 are schematic diagrams of pelletizing machines, called horizontal shaft; Figure 9 shows a sectional view in a vertical plane of the machine of Figure 5; - Figure 10 shows a longitudinal sectional view (in a vertical plane) of a machine of the type of Figure 5; FIG. 11 shows a longitudinal sectional view (along a vertical plane) of a machine of the type of FIG. 3. The terms "lower" and "upper" refer to a position relative to the ground or to the direction. flow of the treated materials.

The present invention is now described with reference to the following figures which show views of machines for the manufacture of granules from materials of all kinds, such as for example wood chips or foodstuffs.

The principle of these machines is to compress and extrude materials which are fed into a compression chamber provided with at least one (and preferably two) rotary compression roll, the materials being crushed between the roll or rolls and the die formed by the walls of the chamber. Figures 1 to 8 are schematic diagrams of different types of pellet machines to which the invention applies. Identical or similar elements from one figure to another bear the same references. The rotating parts are shown in gray and the fixed parts in black. FIGS. 1 and 2 show machines with a vertical shaft where the chamber is fixed and the rollers are mounted on a horizontal common shaft, itself driven in rotation by a vertical tree. According to Figure 1, on the floor or a fixed frame 1 rests a compression chamber 2 of cylindrical shape with circular base, vertical axis X-X. The chamber 2 comprises an open top wall 3, in the form of a flat ring, a longitudinal side wall in the form of a ring 4 and a bottom 5 provided with holes 6. Io Inside the chamber 2, two compression rollers 7 and 8 are mounted to free rotation on a horizontal shaft 9. The periphery of the rollers 7 and 8 is in contact with the bottom 5 of the chamber 2, and more precisely the bottom zone 5 provided with the holes 6. The bottom zone 5 and the holes 6 form a die for the formation of granules.

The horizontal shaft 9 is integral with a vertical shaft 10 centered on the axis of symmetry XX and mounted on a bearing 11 fixed and resting on the ground or frame 1. The chamber rests on the ground or the frame 1 by said bearing 11. The vertical shaft 10 is rotated (arrow F) by known means not shown. The chamber 2 is fixed and the rollers 7 and 8 are rotated on one hand on themselves (arrows G and H), and on the other hand around the vertical shaft 10 (arrow 25 F).

The arrows I and J schematically symbolize the flow of compressed powder materials, then transformed into granules and finally evacuated. The powdery materials to be treated are conveyed into the chamber 2 through the opening 30 provided in the upper annular wall 3, and then are crushed between the bottom 5 of the chamber and the compression rollers 7 and 8, before being extruded in the form granules through the holes 6 in the bottom 5, then removed from the chamber. The machine of FIG. 2 is a variant of that of FIG. 1 in that: the chamber 2 rests on the ground or is constructed by a fixed upright 11A; and - the rotational drive of the rollers 7 and 8 is performed by a vertical shaft 10A (integral with a horizontal shaft 9) by the upper part of the chamber 2.

Figures 3 and 4 show machine diagrams in which it is the chamber 2 which is rotated (arrow K) while the rollers turn Io on themselves on a fixed common shaft.

More specifically, the rollers 7 and 8 are mounted in free rotation (arrows G and H) on a horizontal fixed common arm 12, itself secured to a vertical upright 13 integral with the ground or frame 1. The chamber 2 is mounted on a rotating bearing 14 secured to the bottom 5 and collinear to the upright 13 supporting the shaft 12.

The machine of Figure 4 is a variant of that of Figure 3, wherein the fixed horizontal arm 12 carrying the rollers 7 and 8 is integral with a vertical post 13A opening from the upper wall 3 of the open chamber 2 and whose distal end is fixed to a fixed structure (not shown). The chamber 2 is rotatably mounted on a vertical shaft 14A.

Figures 5 to 8 are horizontal shaft machine diagrams.

Figures 5 and 6 show machines in which the chamber 2 is rotated (arrow L) along a horizontal shaft and constitutes a rotor. The rollers are freely rotatably mounted on two respective arms which are themselves connected to a fixed vertical shaft.

With reference to FIG. 5, the rotor chamber 2 comprises an open end wall 3 in the form of a flat ring, a rear end 5, and an annular wall 4 provided with holes 15. The rollers 7 and 8 are mounted for free rotation each 16 and 17. The latter are secured to a vertical fixed secondary upright 18 which is fixed on a horizontal arm 19. The rotor chamber 2 is integral with a rotating bearing 20 (on the side opposite the open end wall 3) itself rotating around the main shaft 19.

The materials are introduced (arrow M) through the opening of the wall 3, then enter the chamber, then are crushed between the inner face 4A of the annular wall 4, and then fall by gravity out of the chamber, after their Io passage through the holes 15 in the form of granules. This path is the same for the machines of Figures 5 to 8.

According to the variant of FIG. 6, the chamber, driven in rotation (arrow L), is integral with a rotating shaft 21, while the vertical fixed secondary upright 18 15 (carrying the rollers 7 and 8) is integral with a horizontal main arm 19A opening from the opening of the front wall 3 of the rotor 2.

Figures 7 and 8 show machines where the chamber 2 is fixed and the rollers 7 and 8 rotate on one hand on themselves (arrows G and H) and on the other hand (arrow N) around a tree central horizontal 22.

In FIG. 7, the rollers are mounted for free rotation each on a respective horizontal auxiliary shaft 16, 17. These are secured to a secondary support arm 23 rotating in a vertical plane and fixed on the rotating main shaft 25. .

The main shaft 22 is rotated around itself in a fixed bearing 24 on which is fixed the rear bottom 5 of the chamber 2.

The variant of FIG. 8 differs from that of FIG. 7 in that the rotating main shaft 22A (bearing indirectly the rollers 7 and 8) opens out of the opening of the front wall 3, whereas the fixed chamber 2 5 is a diagrammatic section, in a vertical plane of the compression chamber, of the machine of FIG. 5.

In the chamber 2, the two compression rollers 7 and 8 rotate around their respective fixed shafts 16 and 17. The rollers are in close contact, or are flush with, or are very close to the inner face of the annular wall 4 of the room 2.

The present invention will hereinafter be described in detail with reference to Figs. 10 and 10, relating to machines according to the principles of Figs. 5 and 3, respectively, without this being a limitation.

Figure 10 shows a sectional view of a machine according to Figure 5, and where the similar elements have the same references.

The machine comprises a central horizontal main shaft 19, along an axis YY, and fixed in a known manner cantilever on a central frame shown in dotted line, by a proximal end 190. Those skilled in the art can refer to French Patent No. 2,863,184, which describes a machine of this type.

The terms "distal" and "proximal" refer to the situation of an element respectively close to and far from the chamber.

On the side of the distal end 191 of the main shaft there is provided a compression and granulation chamber 2 in the form of an annular rotor with a circular base and a Y-axis. Feeding means, known in themselves and not shown, make it possible to convey powdery materials into the granulation chamber (preferably in the central part of the latter).

In the rotor chamber 2, two compression rollers 7 and 8 are mounted for free rotation, each around a fixed auxiliary arm, respectively 16 and 17 parallel to the main shaft 19, each via a bearing or bearing 26, 27 (of the type known per se, for example with needles). The fixed auxiliary arms 16 and 17 are integral with the distal end 191 of the main shaft 19. The two rollers 7 and 8 are in close contact or in very close proximity to the inner face 4A of the annular wall 4 (or die) of the rotor chamber 2. The annular wall is provided with orifices or holes 15, regularly distributed around the perimeter of said annular wall 4. The holes form with the wall 4 a die.

A rotating hub 28 is rotatably mounted on the shaft 19, via a central bearing 29 and a distal bearing 30 (of known types).

The hub 28 is integral on the one hand with the rotor chamber 2, and on the other hand with a pulley 31 mounted on the main shaft 19. A belt (not shown) may bear on a part of the periphery cylindrical pulley 31, which is preferably provided with asperities or notches. The belt is itself connected to another pulley driven in rotation by a motor (the motor, the other is pulley and the belt are known in themselves and are not shown).

Thus, the drive of the pulley 31 drives the hub 28 in rotation, and therefore the rotation of the compression rotor 2, the assembly rotating around the fixed main shaft 19. The injected materials (arrow M1) in the chamber 2 are compressed and compressed between the inner wall 4A of the chamber 2 and the outer surface of the compression rollers 7 and 8. The crushed material is then extruded through the orifices 15 provided on the annular wall of the chamber 2, resulting in the creation of granules of material. Then, these granules fall by gravity out of the orifices 15 (arrow M2).

According to the invention, the machine comprises a lubricating circuit of the rotating elements and further ensuring the cooling thereof, said circuit 30 comprising: a "go" circuit for conveying a lubricating and cooling liquid from an external source to the rotating elements, namely bearings: central 29 and distal 30 of the pulley 31, and 26 and 27 of the rollers 7 and 8; It a "return" circuit to recover the used or polluted liquid on the one hand and loaded with calories on the other hand, after passage in the bearings and return it to means of treatment and recycling.

The inlets and / or outlets of the lubricant and heat transfer fluid may have several variants, such as for example at the ends of: - the main shaft; or - roller bearing pins. In the latter case, the evacuation of the polluted and calorie laden liquid can be carried out from the front of the machine.

The "return" liquid circulates, according to the invention, in the body of the machine, and in particular at the level of the bearings (where the rise in temperature is the most important with regard to the crushing of the material). The "return" liquid thus participates in the cooling of the bearings and the machine.

The fixed main shaft 19 is hollow and comprises along its entire length, a central cylindrical recess 32 which borrows the two lubrication circuits respectively "go" (black color) and "return" (gray color). The "go" lubrication circuit, shown in black color, comprises: - a first channel 33 and a second channel 34 disposed parallel and longitudinally in the central recess 32 of the shaft 19, each of whose proximal ends 33A and 34A is connected to a source of liquid, in this case a reservoir 35, for conveying the liquid to the respective bearings 26 and 27 of the compression rolls 7 and 8; a third channel 36 disposed in the central longitudinal recess 32 and whose proximal end 36A is connected to said reservoir 35 and the distal end 36B opens via a transverse line 37 into the central bearing 29 (of the pulley 31) ; an inner conduit 38 connects the latter to the proximal bearing 30 (of the pulley 31).

The distal ends 33A, 34A and 36A of the respective channels 33, 34 and 36 are connected to the reservoir 35 via a distribution box 39, a submerged pump 40 controlled by a motor 41 and connected to a plunger pipe 40A.

For more details relating to the first and second channels 33 and 34, one skilled in the art can refer to the patent cited above.

The "return" lubrication circuit includes the central recess 32 provided inside the main shaft 19, and the distal end 32A of which opens into the reservoir 10 through a vertical transverse discharge conduit 42 in order to evacuate the lubrication fluid polluted or used on the one hand and loaded with calories on the other hand.

The tightness between the rotating and fixed parts is achieved by means of joints known as "cassette seals", of a type known per se and comprising a ring set on the axis 1s to which is fitted a second ring set on the bore , and several sealing lips. Those skilled in the art can choose the type of seal most appropriate to the machine, depending on the conditions of use: pressure on both sides of the lip of the seal, produced on both sides of the seal , rotational speed, temperature, mechanical conditions of use and mounting, etc. The "forward" lubrication channels 33 and 34 convey the lubricant each to a compression roller 7, 8 by a respective bypass 43, 44 transversely to the axis YY, located at the proximal end 191 of the shaft 19. The branches 43 and 44 are extended by a respective longitudinal duct 45, 46, each connected to a transverse duct 47, 48 opening into the bearing respective 26, 27 of each roll 7, 8.

The used liquid is discharged from each of the bearings 29, 30, 26, 27 by the "return" circuit to waste liquid treatment and recycling means which are described in detail hereinafter (FIG. 10).

The "return" circuit (gray color) discharges the liquid having lubricated the bearings 26 and 27 of the rollers 7 and 8 and further charged with calories, towards the internal longitudinal recess 32 of the shaft 19 via the connected pipes. between them and following (starting from the rollers): a pair of parallel radial pipes 49, 50 (one pair for each bearing); - A longitudinal pipe 51, 52; - A radial pipe 53, 54 opening into the distal end 32B of the longitudinal recess 32.

In addition, the "return" circuit connects the central and distal bearings 30 and 30 to the inner longitudinal recess 32 via radial pipes 55, 56 that are slightly oblique.

The overall lubrication circuit thus comprises the reservoir 35 containing lubricating liquid, from which the "go" circuit and into which the "return" circuit 1s opens. In the embodiment shown, the pumping, filtering and cooling means operate continuously; there is therefore no device for separating the lubricating liquids, respectively clean and cooled from the "go" circuit and polluted and hot circuit "return".

The liquid coming from the internal recess 32 (discharged via the evacuation pipe 42): - on the one hand is "used" or polluted in that it was used to lubricate the bearings respectively central 29 and distal 30 , and the bearings 26 and 27 of the rollers 7 and 8; and 25 - on the other hand contains the calories recovered as it passes inside the machine. The "return" liquid circulates, according to the invention, in the body of the machine, and in particular at the level of the bearings (where the rise in temperature is the most important with regard to the crushing of the material.

The fluid is both a lubricant and coolant, so as to lubricate and actively participate in the cooling of the machine and in particular the bearings. The machine according to the invention further comprises means for treating and recycling the lubricant discharged and consisting of or comprising a coolant 5 (or heat transfer fluid), connected to the reservoir 35, and comprising a filtration unit 57 receiving liquid from the reservoir through a conduit 58 immersed via a pump 59 (associated with a motor 60) and reinjecting the treated liquid in the tank via a conduit 61. The filtration unit 57 and / or the distribution box 39 further include means measuring and flow control, associated with measuring means and pressure control, known in themselves and not shown.

In addition, the treatment means 57 comprise a heat exchanger system for evacuating the calories of the liquid taken from the reservoir before reinjection (purified and cooled) into the reservoir.

The "go" circuit and the "return" circuit thus constitute a sealed internal circuit 15 in which circulates the fluid, both lubricant and coolant, which irrigates the rolling elements of the bearings and / or the parts in friction. This fluid is recovered outside the machine, then filtered, cooled and reintroduced into circulation in the machine. Thus, the mechanical parts and the worked material are cooled as close as possible to the 20 calorie generation zones.

FIG. 11 shows a variant of said machine with a vertical axis and more precisely of the type of FIG. 3, seen in longitudinal section, in a vertical plane, and where the elements similar to those of FIG. 10 include the same references. The main central shaft is vertical, and the elements are, relative to those of the machine of Figure 10, in the horizontal and vertical inverted position respectively.

The fixed auxiliary shafts 16 and 17 carrying the rollers 7 and 8 are horizontal and the bottom wall 4 of the chamber 2, in the form of a flat ring, is rotated by the bearing 28 secured to the pulley 31.5 the internal channels 33 , 34 and 36, of the "go" circuit, are arranged in the hollow main shaft 19 are connected by their proximal end 33A, 34A and 36A to the tank 35 of liquid, and their distal end to the bearings 29 and 30 of the bearing 28 and the bearings 26 and 27 of the rollers 7 and 8.

The material which is fed by the upper part of the chamber 2 (arrow M1) is compressed between the rollers 7 and 8 and the inner wall 4A of the annular die 4 of the chamber 2, to be evacuated (arrow M2) by a chute 62.

Claims (7)

REVENDICATIONS1. Machine for producing granules from a material, by pressure, of the type 5 comprising: - a central shaft; - A compression chamber, mounted either fixed or rotated on said central shaft, and whose outer wall is a die for extruding the material; At least one compression roller mounted for free rotation on a secondary shaft, in the chamber and whose periphery is in contact with the inner wall of the latter; means for rotating the chamber, the secondary shaft or both; Means for lubricating the rotating elements, comprising lubricant fluid circuits, able to discharge the used lubricant out of the machine; characterized in that it comprises means of circulation said "return" able to allow at least a portion of the used lubricant to circulate inside the machine, before evacuation out of it. 20 2. Machine according to claim 1, characterized in that said circulation means "return" of used lubricant inside the machine are means for cooling the latter. 25 3. Machine according to claim 2, characterized in that the passage of the used lubricant into the machine, before evacuation out of it, is located at least partly in said central shaft provided for this purpose with a central recess. 30 4. Machine according to one of claims 1 to 3, characterized in that said lubricating fluid further has heat transfer fluid properties. 5. Machine according to one of claims 1 to 4, characterized in that it is of the type in which the central shaft is fixed. 6. Machine according to one of claims 1 to 5, characterized in that the lubricating means comprise two circuits "go" supply lubricant namely: - a first circuit opening near the rotor support means, such only bearings; a second circuit passing through said central shaft, and one end of which opens into the compression roll or rollers. io 7. Machine according to one of claims 1 to 6, characterized in that the lubricating means further comprises a lubricant recovery tank that has been used (polluted and loaded with calories), connected to filtering means and cleaning the lubricant, themselves associated with means for regulating and measuring the flow, the latter being themselves connected to each of said "feed" supply circuits of regenerated and cooled lubricant.