FR2779362A1 - Impact anvils for vertical axis grinder - Google Patents

Abstract

The impact surface comprises several cylindrical anvils (4) regularly distributed on an annular ring. The anvils are pivoted on the ring so as to present on the rotor side a part of their surface not subject to wear. The anvils are provided at their base with a coaxial cylindrical foot (5). The lower surface of the foot is provided with positioning teeth (6) enabling different angular positions to be indexed and to allow the anvil to be pivoted by a drive system acting on the teeth.

Description

1 2779362

  Impact anvils for vertical axis shredders The invention relates to vertical axis shredders and more particularly the impact crown on which the materials to be ground are projected by the ejectors of the

rotor in order to be reduced.

  The vertical axis shredders are, schematically, made up of a container in the form of an essentially cylindrical box surmounted by a hopper for introducing the materials. Inside, an axially disposed rotor is provided with ejector elements which, when the rotor is rotated, projects the materials towards the internal wall of the container, provided in this zone with a crown constituting a surface.

impact.

  The materials are introduced through the hopper and fall by gravity to the center of the rotor. They are then forced towards its periphery by centrifugal force, guided by the surface of the ejectors and are ejected at

  the end of said ejectors at a certain angle.

  Generally, the impact surfaces consist of a crown carrying on its inner surface elements in relief of hard material, for example anvils, stone boxes or the like, on which the materials to be treated, projected by the ejectors of the

rotor, break.

  The elements in relief or anvils of the crown forming the impact surface are therefore permanently stressed by the impact of the projected materials and wear out more or less quickly depending on their hardness and the nature of the material treated. Therefore, they must be replaced periodically in order to keep an effective impact crown. This results in an expenditure in components and in time which one must try to reduce.

  in order to lower the operating cost.

  This object is achieved, according to the invention, thanks to an impact surface characterized in that it is constituted by a plurality of anvils regularly distributed on an annular ring and mounted thereon so as to be able to pivot on a axis in order to present on the rotor side a part of their surface which has not yet been subject to wear, when their surface previously presented in this direction has been worn

by impacts.

  According to a first embodiment of the invention, the pivoting of each anvil is controlled independently of that of the other anvils, depending

  the degree of wear of the exposed surface of the anvil.

  According to a second embodiment of the invention, the pivoting of all the anvils (4) is

ordered simultaneously.

  According to the invention, the anvils intended for the impact surface can be of cylindrical shape,

  parallelepipedic or prismatic.

  According to a particular form of the invention, the anvil comprises at its lower part a cylindrical foot whose lower surface is provided with

  indexing and drive teeth.

  According to another particular form of the invention, the anvil is provided with an axial bore enabling it to be mounted on a support by means of an axis of rotation or

a training tree.

  According to a particular form of the invention, the anvils can be provided with a pinion integral with their axis of rotation, the pinion being engaged with a

  gear ring driven by a motor.

  Thanks to the invention, when the surface part exposed to the projected materials of the anvils, cylindrical or other, has undergone a first wear, the anvils are pivoted on their axis in order to make them present on the exposed side another part which is not yet stressed . This allows the wear to be distributed over the entire perimeter of the

  anvils and therefore extend the life of these

  and reduce the loss of time due to changing

  wear parts of the impact surface.

  The effectiveness of impact grinding is partially dependent on the angle of impact on the impact surface (initially around 90). With the anvils of the prior art which are generally teeth, this angle evolves towards values completely different from the starting value and correlatively modifies the particle size exit curve. With cylindrical anvils according to the first embodiment of the invention, it is already started with angles other than 90 due to the curvature of the surface, therefore the variation in the particle size exit curve is smaller. This results in regularity

  improved grinding size.

  The invention will be better understood by means of exemplary embodiments represented in the appended drawing, in which there is shown: FIG. 1: a schematic sectional view from above of a mill with vertical axis provided with the impact surface according the invention; Figure 2: a perspective view of a 2S anvil according to a first embodiment of the invention; Figure 3: a perspective view of an anvil according to a second embodiment of the invention; Figure 4: a schematic perspective view of an anvil according to a third embodiment of

the invention.

  The mill shown schematically in Figure 1 is a vertical axis mill. It comprises a rotor 1 provided with ejectors 2, rotating in a box, not shown. On the periphery of the box is an impact surface made up of anvils 4 regularly

  distributed around the perimeter of the box at the rotor.

  These anvils 4 are mounted on a crown 3 so

to be able to pivot on their axis.

  The materials falling by gravity to the center of the rotating rotor 1 are centrifuged towards the periphery thereof, guided by the ejectors 2 and projected against the anvils 4 of the impact surface. They then burst into smaller parts which fall into a hopper of

  recovery, not shown, located below.

  In doing so, they wear the face of the anvils exposed to impact. When the wear of this face has reached the maximum allowable, the anvils are pivoted, individually or together, manually using a lever arm, or controlled by a motorized system in

connection with the anvils.

  According to a first embodiment, these anvils are produced in cylindrical form. As shown in Figure 2, the anvil 4 consists of a cylinder provided at its base with a cylindrical foot 5 coaxial with the anvil. The lower surface of the foot is provided with positioning teeth 6 making it possible to index the different angular positions of the anvil and to allow the latter to pivot by a system

  acting on teeth 6.

  According to a second embodiment, shown in FIG. 3, the anvil is of cubic or parallelepiped shape in order to present edges at the

  projected materials and improve their disintegration.

  According to a third embodiment, the anvil 4 has an axial bore 7 into which penetrates either a fixed axis, the body of the anvil then being driven directly, for example by a system identical to that of the first two examples, or a shaft integral in rotation with the anvil and driven itself to make

rotate the assembly.

  Thanks to the invention, one should no longer change the anvils of the impact surface each time the face À sguimao] gpgd sdmo]> 9p salIieAao] IU sap e '(awnftuo, I ap uo3Das Pe uolas) albue uIle- ao çl un, p ouuojnoo eP ap sa ^ Kssoonfs suo [ceAoa Jed anua; qo sa iwnIDua.1ap a9j; sdwoDaansnSl 'gJaTUeWa aa * anal axis ap oTepTTos uouSfTd un Jed Tu- soIIo ueu! eua a snwniou sI quueîoddns [nePeid np T1qTcIJagcd eIl snos no ans aqn4! s) u3iu! n] 4uap auuomnoo aun Ol o DpE sawntLDua sap aguPlInWTs uoTe4P-1o P1 agnsse n ad uo 'luawauuor- U4Tsod ap s-uap e, auw; sÀs np na r nv <(asn awnLf) ufaU aunD aPsLw assew) anbTDsseW 4uWapu9J JnlIITaw un ao [nsUJ ua Ii 'saosn uawupesijjns so, 6nC 4uos s; ^ AT! âe sa41Ped sal anbsiol anb nlTI eu quawa6ueqoD aq -1oddns Jnar snn-nsn -n snrsnd sa2OATd ap suanald wnu saI sn o uD SU POuowi0 p ap 4a afieuow ap sduia saj aa-no ua arTwouoDi uo * aqsn â asodxa

Claims (9)

  1. Impact surface for a vertical axis mill, in which a rotor provided with ejectors projects materials to be ground onto an impact surface. cylindrical concentric with the rotor, characterized in that it is constituted by a plurality of anvils (4) regularly distributed on an annular ring (3) and mounted thereon so as to be able to pivot on an axis in order to present on the side of the rotor (1) a part of their surface which has not yet been subject to wear, when their surface previously presented in this direction has been worn by impacts.   2. impact surface according to claim 1, characterized in that the pivoting of each anvil (4) is controlled independently of that of the other anvils, depending on the degree of wear of the surface exposed from the anvil.   3. Impact surface according to claim 1, characterized in that the pivoting of all the   anvil (4) is controlled simultaneously.   4. Anvil for an impact surface according to claim 1, characterized in that the anvil (4) is cylindrical in shape.   5. Anvil intended for an impact surface according to claim 1, characterized in that the anvil (4) is paralllépi.pédiq.ue.   6. Anvil intended for an impact surface according to claim 1, characterized: ized in that the anvil (4) is prismatic.   7. Anvil according to any one of claims   4 A 6, characterized in that the anvil (4) comprises at its lower part a cylindrical foot (5) whose lower surface is provided with indexing teeth (6) and drive.   8. Anvil according to any one of claims   4 to A 6, characterized in that the anvil 4 is provided with an axial bore (7) allowing it to be mounted on a support by means of a rotation axis or a drive shaft.   9. Anvil according to any one of claims   4 to 6, characterized in that the anvil (4) has at its lower part a drive pinion integral with its axis.