FR2628007A1 - Vacuum percussion material crusher - has wheel on vertical shaft protecting material into vacuum chamber at high speed rotationally driven by motor - Google Patents

Abstract

The percussion crusher has a tank defining a low pressure chamber connected to a vacuum mechamism. There is also a wheel on a vertical shaft projecting material at high speed by centrifugal force placed in the chamber. The wheel is rotatably driven by a motor. A feed device supplies the material to the chamber opening out above the wheel. A target spot takes the impact of the fragments and the fragments are removed from the bottom of the enclosure by a suction device. The target is constituted by material fragments and has a stacking base visible through a circumferential exit in the bottom of a hopper surrounding the rotor on the path of the fragments projected by the wheel. USE - For treatment or material handling requiring fine granulomatric prod.

Description

FRENCH REPUBLIC Publication No. 2 628 007 (Use only for

  NATIONAL INSTITUTE reproduction orders

PROPERTY: TE INDUSTRIAL

  INDUSTRIAL PROPERTY N national registration: 88 02863 PARIS

(Int CI4: B02 C 19/11, 23/12.

@ APPLICATION FOR A PATENT FOR INVENTION Ai

    Filing date: March 7, 1988. () Applicant (s): ELECTRICITE DE FRANCE, Service Na-

tional - FR.

) Priority

) Inventor (s): Claude Bienvenu.

  Date of public availability of the

  application: BOPI "Patents" n 36 of September 8, 1989.

  (References to other national documents appearing

rented: (r Holder (s):

  _ Agent (s): Cabinet Plasseraud.

  (Vacuum impact crusher, (The crusher comprises a tank delimiting a chamber at reduced pressure provided with a connection fitting with suction means, a wheel 24 with vertical axis of projection of the material at high speed by centrifugal force placed in

  the chamber and provided with a rotary drive motor, -

  a device 14 for supplying the chamber with fragments of the material to be ground, emerging above the wheel, a target intended to receive the impact of the fragments of the material and means for discharging the ground material collected at the bottom of the enclosure. Target 28 consists of fragments of the material

  to grind. The crusher can be used in particular for processing

  I lie low-grade ores.

  O cc O IT. D Sale of booklets at IMPRIMERIE NATIONALE, 27. rue de la Convention - 75732 PARIS CEDEX 15

Vacuum Impact Crusher.

  The present invention relates to vacuum impact crushers, in which the material to be ground is projected against a resistant target through a

  room where reduced pressure prevails, so that

  reduce the braking by the air of the particles projected to

great speed.

  The invention has a very wide field of application. It is of particular interest whenever the grinding of hard material represents a large fraction of the cost of a treatment, which is in particular the case in the treatment of ores

  of low content which must be ground to a granulome-

sorts fine.

  The invention relates more particularly to

  impact crushers of the type comprising a delicate bowl

  mitant the chamber and provided with a connection fitting with suction means, a wheel with vertical axis of

  projection of material at high speed by central force

  trifuge placed in the chamber and provided with a rotary drive motor, a feed device

  of the chamber into fragments of the material to be ground,

  mortally through an airlock, opening above the

  wheel, a target intended to receive the impact of frag-

  material and means of material evacuation

  ground collected at the bottom of the enclosure.

  Impact crushers of the type defined above are already known (FR-A2 577 445 and 2 594 048). The target of these shredders is generally constituted by plates of hard and impact-resistant material, such as

  that tungsten carbide, distributed around the en-

  surrounded on the path of the fragments of material to be ground. These plates wear out quickly. They often have to be fitted with a cooling circuit to avoid overheating which would adversely affect their mechanical properties. The present invention aims to provide a grinder

  of the type defined above responding better than those before

  known to the requirements of practice, in particular

  in that it largely eliminates the problems of wear of the target. For this purpose, the invention proposes a crusher in which the target is made up of material to be ground of the same kind as the projected material. This target can in particular be the bottom part of a stack of fragments of the material to be ground, visible through a circumferential outlet formed at the base of a hopper surrounding the rotor and arranged

  on the trajectory of the fragments projected by the wheel.

  It can also be formed by the upper part of a

  stacking carried by lifting means and appear-

  health through a circumferential outlet.

  Because the target is made of material to be ground, two favorable results are obtained. On the one hand, we avoid the investment represented by traditional targets which must be replaced frequently; on the other hand the wear of the target itself contributes to

the production of crushed material.

  It should be noted that there are already known (FR 2 329 350) projection mills comprising several injectors supplied with material to be ground, previously crushed, and with propulsion fluid which forms a jet.

  chasing material at high speed out of injec-

  teurs. The axes of the injectors are directed towards a common area where the crushed fragments collide with one another. This solution implies the presence of a propellant fluid, incompatible with the maintenance of a high vacuum in the grinding chamber which prevents braking by air. And we cannot compare the collision of two jets, which causes ricochets striking the walls with violence in all directions, to the sending by centrifugal force of fragments animated by a

  well defined orientation speed towards a fixed target.

  The invention will be better understood on reading

  the following description of a particular mode of

  embodiment, given by way of nonlimiting example. The

  description refers to the accompanying drawing, in

  which: - Figure 1 is a simplified representation of an impact mill according to the invention, in section along a vertical plane passing through its axis, - Figure 2 is a sectional view along the

line II-II of figure 1.

  The impact crusher shown schematically

  in Figures 1 and 2 has a conventional general constitution.

  It comprises a tank 10 provided with a connection 12 for connection with a vacuum pump making it possible to reduce the air pressure which prevails inside the tank. This is

  surmounted by a device 14 for supplying frag-

  of the material to be ground. In the embodiment

  shown in figure 1, this device is formed by a

  crumb, the bottom of which converges towards a discharge orifice which can be controlled by means such as a vibrator 16. If it is desired to be able to reload the hopper with material to be ground during operation or without "breaking" the vacuum, the hopper may be provided with a transfer airlock instead of a simple sealed cover 18. The tank carries, by means of bearings 18, a rotary assembly comprising a vertical shaft 20 which carries the rotor of an electric motor 22 d drive and a projection wheel 24. The fragments of material to be ground fall into a sleeve 26 which brings them into the axis of the wheel, from where they are projected by centrifugal force. The constitution of the wheel. 24, which has only been shown diagrammatically in FIG. 2, may for example be that described in the document FR-A-2 594 048. The target for receiving fragments, placed around the wheel , is constituted by the lower part of a stack 28 of material to be ground. This material is placed in an annular hopper surrounding the upper part of the tank and opening by a circumferential outlet formed at its base. The height of the outlet must be proportional to the size of the pieces of pre-crushed material placed in the annular hopper 30,

  so as to limit the falling of material whose dimension

  Zion has not yet been reduced by the wear and tear from the impact of the projected fragments. To retain the material

  crushed, vertical bars in a resistant material

  both wear and impact can be arranged at regular intervals across the outlet. Being

  as these bars will be subject to only a few

  compacts and will represent a much smaller volume of material than in a traditional grinder, they

  can be made or coated with ultra-

  hard, possibly in the form of pawns reported by

  brazing, in cubic boron nitride for example.

  The outlet of the hopper 30 is placed above deflectors 32 which collect the grinding particles and guide them towards an evacuation ramp 34 opening by a valve 36 in an apparatus 38 for grading according to the particle size. The particles of fine particle size are extracted by an outlet 40 while the coarse particles of dimensions greater than a threshold, rejected by a sieve, are taken from an outlet 42 and are recycled to the hopper 14. The invention is susceptible of numerous variants of achievement. In particular, the means intended to maintain the material to be crushed constituting the target facing the trajectory of the fragments can have various constitutions. The material can be carried by progressive lifting means renewing the target by bringing material to the level of the opening as and

  as it wears. If you keep a hopper

  mentation of the gravity outlet, the means of feeding

  Progressive tation by drawer, avoiding the spillage of the whole of a reserve under reduced pressure, can be provided. It should be understood that the scope of this patent extends to such variants and more generally than to all others remaining within the framework of equivalences.

? 628007

Claims (5)

  1. Impact crusher comprising a tank delimiting a chamber at reduced pressure provided with a connection fitting with suction means, a wheel with vertical axis of projection of the material at high speed by centrifugal force placed in the chamber and provided with '' a rotary drive motor, a device for supplying the chamber with fragments of the material to be ground, opening out above the wheel, a target intended to receive the impact of the fragments of the material and means of evacuation ground material collected at the bottom of the enclosure, characterized in that the target consists of fragments of the material to be ground. 2. Crusher according to claim 1, characterized in that the target is constituted by the lower part of a stack (28) of the material to be ground, visible through a circumferential outlet formed at the base of a hopper (30) surrounding the rotor and arranged on the   trajectory of the fragments projected by the wheel (26).   3. crusher according to claim 2, characterized   in that said circumferential outlet is fraction-   born by bars distributed at regular angular intervals.   4. Crusher according to claim 2 or 3, charac-   terized in that the hopper (30) is designed to receive fragments of material of grain size such that   do not escape freely through the outlet.   Crusher according to claim 1, characterized in that the target consists of the upper part of a stack carried by lifting means and   appear through a circumferential exit.   6. Crusher according to any one of the claims.   above, characterized in that deflectors (32) for guiding a collection ramp are arranged below the target.   7. Grinder according to any one of the claims.   tions, characterized by means of sorting the ground material and recycling fragments of large size towards the target. 1/1 12ô FIG.1. 106 E | i 28 \ 4X L18 X2 'en- FIG.I2. -18 -22 18 FIG. 2.