FR2610218A1 - Rotary crusher with projection - Google Patents

Abstract

The rotor of the crusher receives the stones to be crushed via an axial chute 6 wherefrom they fall onto a central distributor 30 which directs them towards the projection vanes which connect the floor 8 to the top 9 of the rotor and which project these stones tangentially onto outer impact surfaces. The floor 8 is mounted on the shaft 2 by means of a carrying plate 34 which makes it possible to decrease the weight of the rotor. The floor is applied against this plate by means of an axial screw 33, the distributor 30 and an intermediate washer 36. Application to crushing abrasive stones.

Description

 The present invention relates to the crushing of stones, with a view to obtaining fragments thereof. It applies more particularly to the crushing of hard or abrasive stones, such as those whose fragments are sometimes used for the construction of roads. The essential problems posed for the production of a crusher suitable for this purpose are linked to its wear by these stones and their fragments.

 We therefore seek on the one hand to obtain good resistance to this wear, on the other hand to reduce the cost of replacing worn parts, this cost being constituted by that of the parts and by that of the labor required for replacement.

 To solve this problem, known crushers include the following elements which are common, at least as regards some of their functions, to these crushers and to that according to the present invention - a shaft arranged along a vertical axis of rotation, - means for guide and drive this rapidly rotating shaft, - a floor disposed at the top of this shaft, centered on said axis and constituting at least part of a projection rotor, - means for connecting this floor to this shaft to guide and drive this rotor in rotation through this shaft and this floor, - a central distributor made of a hard material, and f-fixed projecting upwards on a central area of this floor to receive crushing stones falling on this floor along said axis and to spread them radially towards the periphery of the floor where the rotation of the rotor causes a centrifugal force to prevail, - projection vanes carried by this floor, these vanes rising v upwards from it and towards the periphery from said distributor to receive the stones coming from this distributor, to guide them in their movement towards the periphery under the action of centrifugal force while applying a thrust which gradually increase their circumferential speed, and finally project them tangentially to the outside of the rotor, - an external receiving structure constituting hard impact surfaces around said projection rotor to receive the stones projected by these blades and break them under impact , - and exit means for the fragments of the stones thus broken.

 Such known crushers are for example described by patent documents US-A-3,174,697 (Bridgewater) and 3,970,257 (Mac Donald), the latter corresponding to document FR-A 2,201,928 (same name).

 The rotor is conventionally formed from thick sheets of hard steel cut and welded. It is preferably balanced in rotation to minimize the forces applied to said means to guide it. These means are bearings arranged around a tree sheltered from stones under the floor of the rotor.

 The speed of rotation of the rotor is for example about 1110 revolutions per minute, the distance to the axis of the projection edge being about 47 cm.

 The external receiving structure is for example a fixed stator, the impact surfaces of which may consist of hard cast iron or chrome plates oriented approximately perpendicular to the trajectories of the stones projected by the rotor and called anvils.

The wear of plates thus oriented is in fact less than that of otherwise oriented plates, the stones of which scrape the metal. The more effective the impact is the better. Such a structure of the stator is for example described in the document Bridgewater previously cited.

 The wear of the stator can however be reduced by self-protection, by giving it the form of a stone box open towards the rotor and in which a protective layer is formed maintained by natural gravity. The shock surfaces are then formed by the fragments of stones previously received by the stator. Such an arrangement is for example described in patent documents US-A2,985,391 (Parmele) and the document Mac Donald previously cited.

Other stator structures are possible, the choice of the stator obviously not being linked to that of the rotor.

 The output of the fragments of stone obtained can be done for example by gravity, that is to say through one or more passages formed in the stator around the floor of the rotor. Other structures of the output means can also be used there, whatever the structure of the rotor and that of the impact surfaces of the stator.

 A known crusher further includes a central distributor supported on said floor. This distributor is fixed using an axial screw which screws into said shaft and the head of which is placed at the bottom of an axial well dug in the upper face of this distributor.

This well is filled in service with stones which protect this head from wear.

 Under this distributor, the rotor floor is fixed to the shaft by a system which includes numerous screws.

 This known crusher has various drawbacks.

 One is that the rotor floor is relatively thick and stiff to have sufficient rigidity in service. The cost price of such a rotor is therefore high, which makes it expensive to replace when some of its parts are definitively worn.

 Another drawback is that the cost of this replacement is further increased by that of the labor required for dismantling the worn rotor and mounting the new rotor.

 The object of the present invention is to produce a crusher of the kind indicated above so as to reduce the operating costs linked to the replacement of the rotor by reducing the cost of such replacement without harming either the efficiency of the crusher or the resistance of the rotor to wear.

 It also aims to reduce the severity of the damage that appears when a user lets the wear of the rotor progress a little beyond what is recommended by the manufacturers.

 It relates to a crusher comprising the common elements mentioned above, this crusher being, with respect to known crushers comprising these elements, characterized in that said floor is pierced with a central hole receiving said distributor, - said connecting means between said floor and said shaft comprising, - a carrier plate separable from the floor, disposed under the latter, and having an intermediate diameter between that of said tree and that of this floor, - means for connecting this carrier plate to this tree, - a protrusion on the underside of said floor cooperating with a recess in the upper face of the carrier plate to prevent horizontal translation of the floor, - an intermediate washer disposed at the bottom of said central hole drilled in the floor, the outer edge of this washer cooperating with the edge of this central hole to support this floor on the support plate, said central distributor being disp dared in this same central hole above this washer to press it on this tray, and thus support the floor on the tray via the edge of this washer, - and means to prevent relative rotation of the floor relative to the carrier plate.

 According to the invention, the following preferred arrangements can also be adopted. Said protuberance on the underside of the floor is a central annular protuberance surrounding said central hole in this floor which receives said distributor, the interior surface of this protuberance constituting the edge of this hole. at the bottom of it and cooperating with the outer edge of said intermediate washer.

- Said axial well dug in said central distributor is deep enough for the head of said axial screw placed at the bottom of this well to be below the level of the upper face of said floor.

- The internal diameter of said intermediate washer is greater than the diameter of this axial well so as to keep this distributor sufficient thickness around this well to safely transmit to the peripheral part of this distributor the vertical bearing force applied by the head of this axial screw at the bottom of this well.

- The outer edge of said intermediate washer is slightly tapered male with tip down, the edge of said central hole drilled in the floor being tapered female.

- Said annular protuberance on the underside of the floor has a circular external edge and cooperates with an obviously also circular in said support plate, said means for preventing the relative rotation of the floor comprising a radial key engaging in this plate and / or this floor .

- Said radial key extends inwardly engaging in said intermediate washer and said central distributor.

 Using the attached schematic figures, a more specific description will be given below, by way of nonlimiting example, of how the present invention can be implemented within the framework of the description given below. above. When the same element is represented in several figures, it is designated therein by the same reference sign. Implementation described includes the provisions mentioned above as preferred according to the present invention. It should be understood that the elements mentioned may be replaced by other elements ensuring the same technical functions.

 - Figure 1 shows a side view of the assembly of a first crusher according to the invention, in axial section.

 - Figure 2 shows a side view of the assembly of a second crusher according to the invention, in axial section.

 - Figure 3 shows a horizontal sectional view of the rotor with three blades of any of these two crushers, for example the first.

 - Figure 4 shows a top view of the front section of a projection vane of this rotor whose ceiling is assumed to be removed.

 FIG. 5 represents a side view of the same front section.

 Figure 6 is similar to Figure 4 and shows a top view of a rotor projection vane of the other of the two said crushers, for example of the second.

 Figure 7 shows a view of the rotor of Figure 4 in section through an axial plane.

 In accordance with FIG. 1, a first crusher with self-protected projection vanes according to the invention has a vertical axis A and it comprises a projection rotor 1. The latter is mounted on a vertical shaft 2 provided with protected bearings not visible in the figure. This shaft is driven in rapid rotation by a motor 5 via pulleys 3A and 3B and a belt 4.

 The rotor 1 has a floor 8 and a ceiling 9. The latter is pierced with a central circular opening in which engages a vertical chimney 6 channeling the stones from a hopper 7.

This chimney is provided with a device 5 making it possible to correct its level in the rotor as and when it is worn by the stones which constitute the material to be crushed.

 The floor and the ceiling are connected by vertical walls which will be described later using Figure 3.

 The stator of the first crusher is constituted by a horizontal circular crown 11 which constitutes the bottom of a stone box. A vertical cylinder 12 constitutes the external wall of this stator and of the crusher. It is shielded in its upper part, above the level of the crushed material 13. This consists of fragments of the stones which have been introduced into the hopper 7. A certain volume is retained in the stone box. The stator is closed around the chimney 6 by a horizontal shielded cover 14.

 Vertical radial stiffeners 16 improve the holding of the stator and retain the material 13 accumulated in the stone box.

 The crushed material exits towards the lower part of the stator through the annular gap 10 existing between the rotor and the stone box.

It is extracted through a conical bottom 17 then evacuated on a means of transport such as a belt conveyor, to a hopper or any other means of storage.

 2 shows the same side view in axial section of a second crusher which may differ from the first only by its stator the stone box 13 of the first is replaced in the second by anvils 19. The cylindrical casing of the stator 12 is then fitted with an anvil ring 18 allowing the anvils to be fitted and moved vertically 19 thanks to three ramps 18A arranged at 1200 and fitted with stairs. The height of the anvils can therefore be adapted according to their wear by the stones thrown by the rotor. The anvils are orientable relative to the trajectories of the materials coming from the rotor. They can be returned from 1800 to increase their longevity.

 FIG. 3 represents a view in horizontal section of a polygonal rotor in which said number N is three. This rotor has practically the shape of an equilateral triangle with truncated angles. The direction of its rotation is represented by an arrow F. This one-piece construction rotor consists of a horizontal ceiling 9 not visible in this view, a floor 8 also horizontal, made of very thick sheets, and vertical plates 20 , 21, 24, and 25 constituting three projection vanes. Each blade constitutes both a part of the peripheral wall of the rotor and a wall for conducting and accelerating the material to be crushed. Each of these vertical plates constitutes a section of one of these blades.

 Each blade is mainly made up of a main section 20 whose front end joins a front plate 21 constituting said front section. The latter forms a small side of said polygon and its front end is formed by the projection edge 22. As shown in FIGS. 4 and 5, the latter is formed on a projection blade 22A constituted by two removable pieces of superimposed steel 22B and 22C each comprising two vertical bars of tungsten carbide. One of these bars 22D or 22E constitutes a part of the edge 22 and the other such as 23 constitutes a part of a protective bar which increases the longevity of this part. This latter is indeed subjected to abrasion not only by the stones which come out of the projection dawn passing on the edge 22, but also by the fragments of stones which are returned, randomly, after fragmentation on the material retained in the stone box 13, or on the anvils 19 depending on the system used. Bars such as 23 partially protect the blade 22A and the front plate 21 from abrasion by these fragments. They are located at the point of maximum radius of the rotor.

 The parts 22B and 22C are fixed to the fixed part of the front plate 21 by two bolts 31.

 FIG. 5 which represents a side view of the same front plate from the interior of the rotor makes it possible to see these two parts 22B and 22C superimposed, interchangeable, and carrying bars of partial tungsten carbide of identical characteristics such as 22D and 22E. Since wear occurs essentially towards the middle of the front plate, this allows parts 22B and 22C to be interchanged to increase longevity.

 In accordance with FIG. 6, the protective bars such as 23 can be replaced by a hard protective coating such as 23A formed on the exposed surface of each of two parts such as 22F similar to parts 22B and 22C. This coating advantageously consists of small rounded particles or tungsten carbide balls embedded in a binder such as a cobalt nickel alloy. These balls have for example diameters of the order of a tenth of a millimeter.

Such a coating is more resistant to abrasion resulting from oblique shocks from fragments and dust than a solid tungsten carbide bar which lacks ductility or than a coating which would consist of angular particles of tungsten carbide embedded in the same binder. These angular particles would indeed be too easily torn off or broken by the quasi tangential shocks.

On the other hand, a coating with rounded particles such as 23A would be less suitable than the solid tungsten carbide bars 22D and 22F to form the projection edge which is subjected to friction rather than to impacts. Nor does such a coating appear really useful on a protective plate such as the plate 24 which will be described later and which especially receives shocks at right angles.

 Returning to FIG. 3, it appears that the rear end of the front section 21 is closer to the axis of the rotor than its front end.

 The main section 20 of the blade comes by its rear end to limit the outlet opening 21A of the next projection blade.

 A protective plate 24 projects in front of each of the outlet openings of the material projected by the blades. Its circumferentially front face is equipped with a removable wear plate 24B which carries screws 24C which make it possible to fix it using nuts 24D on the circumferentially rear face of the plate 24.

 This plate 24 thus equipped deflects the fragments which ricochet from the stator as well as the air streams charged with dust and sand created by the rapid rotation of the rotor. In this way it thus contributes to the protection of the projection blade 22A and it protects the edges of the floor 8 and of the ceiling 9 around the outlet opening. Each protective plate 24 is placed practically in the radial position. It is integral with the previous projection vane with which it forms an obtuse angle favoring the deflection of the external air streams. This protective plate also extends inside the rotor. Its inner part 24A constitutes both a rear section of the projection vane, with a retaining role towards the rear of the protective layer, and a rear stiffener for the main section 20 of this vane.

 FIG. 3 also shows that each projection vane is equipped with at least one intermediate stiffener 25 projecting inwardly to reinforce the retention. Said reception zone is formed between these two stiffeners 24A and 25.

 This figure also shows wear plates 26 which protect the floor 8 in areas where it is not naturally protected by the layer of material held in the rotor. These wear plates are naturally held in place by centrifugal force, without bolting, thanks to cleats 27, 28, 29 fixed for this purpose to the floor.

 In the center of the rotor, a hole drilled in the floor 8 receives a solid disc 30 called a distributor. The latter has a diameter of the order of one third of that of the rotor, that is to say that of the circle circumscribed to the rotor. It projects from the floor 8 and has two functions: distributing the material received towards the projection vanes and fixing the rotor 1 on the axis of rotation 2, as will be explained with the aid of FIG. 7.

 The rotor 1 is carried and driven by means of its floor 8. According to the invention, the latter is itself carried and driven not directly by the shaft 2 but by a carrier plate 34 which is mounted by mechanical means conventional on the upper end of the shaft 2 whose diameter is much smaller. This carrier plate can be separated from the rotor. It has a diameter slightly greater than half that of the floor 8 and its thickness is sufficient to give it all the desired rigidity. Its presence ensures the rigidity of the rotor while giving only a moderate thickness to the floor. It thus makes it possible to use a relatively light rotor whose replacement cost is relatively low when some of its parts are definitively worn out. However, in order for the cost of replacement labor to be low, the mode of mounting the floor on the support plate is simple to allow easy disassembly. This mounting method must prevent relative horizontal translational displacements, relative vertical displacements, and relative rotations around the vertical axis of the rotor.

 The horizontal translational displacements are prevented by the fact that the floor 8 comprises on the lower face, around its central hole, a central annular protuberance 40 which fits precisely into a central recess of the support plate 34.

 Vertical separation movements are prevented by means of the distributor 30. The latter is fixed to the shaft by a single axial screw 33 disposed in an axial well of this distributor.

 This well is filled in service with stones which protect the head of this screw against wear. The depth of this well is sufficient for this head to be placed below the upper face of the floor 8.

 This allows, when the distributor is worn, to prevent this head from being worn before the floor 8. In fact, it is normally never worn because the rotor is changed before any risk of significant wear of the floor.

 The distributor 30 is made of high hardness steel to withstand wear for a fairly long time. It is therefore difficult and economically unacceptable to machine its peripheral surface with the desired precision for applying the floor 8 to the support plate 34.

 According to the invention a small gap is made between the peripheral surface of the distributor and the edge of the hole drilled in the floor 8. The latter is held by an intermediate washer 36 blocked under the distributor 30. For this the peripheral surface of this washer is slightly conical, in male cone with point downwards, and comes to bear precisely on the inner surface of the annular protuberance 40, which is machined according to a corresponding female cone.

 The risk of wear of the intermediate washer 36 is very low because of its position which provides protection by the distributor 30 and the floor 8.

 As for the rotational movements of the floor 8 relative to the support plate 34, they are prevented by a radial horizontal key 35 which is fixed to the support plate by two vertical pins 37. Housing is dug for this key in the lower faces of the washer 36 and distributor 30 to block them.

 FIG. 7 also shows that the floor 8 and the ceiling 9 are respectively protected by removable wear plates 26 and 32.

The thickness of the plates 26 fixed to the floor is the greatest.

Claims (7)

CLAIMS: 1 / Rotary projection crusher, this crusher being intended to break stones and comprising: - a shaft (2) arranged along a vertical axis of rotation (A), - means (3, 4, 5) for guiding and driving this rapidly rotating shaft, - a floor (8) disposed at the top of this shaft, centered on said axis (A) and constituting at least part of a projection rotor (1), - means for connecting this floor to this shaft for guiding and driving this rotor in rotation via this shaft and this floor, - a central distributor (30) made of a hard material, and fixed projecting upwards on a central area of this floor to receive crushing stones falling on this floor along the said axis and to spread them radially towards the periphery of the floor where the rotation of the rotor causes a centrifugal force to prevail, - projection blades carried by this floor, these blades rising upwards from there and to the periphery from said distributor to receive the stones from this distributor, to guide them in their movement towards the periphery under the action of centrifugal force while applying a thrust which progressively increases their circumferential speed, and finally to project them tangentially to the outside of the rotor, - an external receiving structure (11, 12) constituting hard impact surfaces (13, 19) around said projection rotor to receive the stones thrown by these blades and break them under impact, - and means for outlet (10, 17) for the fragments of the stones thus broken, - said central distributor (30) pressing on said floor (8), being fixed by means of an axial screw (33) which screws into said shaft ( 2) and whose head is placed at the bottom of an axial well dug in the upper face of this distributor, so that this well fills in service with stones which are retained and protect this head from wear, - this crusher being c aractérisé by the fact that said floor (8) is pierced with a central hole receiving said distributor (30), - said connecting means between said floor (8) and said shaft (2) comprising, - a carrier plate (34) separable from the floor (8), disposed beneath it, and having an intermediate diameter between that of said shaft and that of this floor, - means for connecting this carrier plate to this tree, - A protuberance (40) on the underside of said floor (8) cooperating with a recess in the upper face of the support plate (34) to prevent horizontal translation of the floor, - an intermediate washer (36) disposed at the bottom of said central hole drilled in the floor (6), the outer edge of this washer cooperating with the edge of this central hole to support this floor on the carrier plate, said central distributor being disposed in this same central hole above this washer to support it on this plate, and thus support the floor on the plate only via the edge of this washer, - and means (35) to prevent relative rotation of the floor (8) relative to the carrier plate (34). 2 / Crusher according to claim 1, characterized in that said protuberance (40) on the underside of the floor (8) is a central annular protuberance surrounding said central hole of this floor which receives said distributor (30), the inner surface of this protrusion constituting the edge of this hole at the bottom thereof and cooperating with the outer edge of said intermediate washer. 3 / A crusher according to claim 2 characterized in that said axial well dug in said central distributor (30) is deep enough for the head of said axial screw placed at the bottom of this well to be below the level of the upper face of said floor (8). 4 / Crusher according to claim 3 characterized in that the internal diameter of said intermediate washer (36) is greater than the diameter of this axial well so as to keep this distributor sufficient thickness around this well to safely transmit to the peripheral part of this distributor the vertical support force applied by the head of this axial screw to the bottom of this well. 5 / A crusher according to claim 3 characterized in that the outer edge of said intermediate washer (36) is slightly tapered male with tip down, the edge of said central hole drilled in the floor (8) being tapered female. 6 / Crusher according to claim 2 characterized in that said annular protuberance (40) on the underside of the floor (8) has a circular outer edge and cooperates with an obviously also circular in said carrier plate (34), said means for preventing the relative rotation of the floor (8) comprising a radial key (35) engaging in this plate and / or this floor. 7 / Crusher according to claim 6 characterized in that said radial key (35) extends inwardly engaging in said intermediate washer (36) and said central distributor (30).