FR2594049A1 - HAMMER GRINDER. - Google Patents

Abstract

Hammer mill for crushing hard and soft substances, comprising a casing 1, a feed opening 11 for the material to be crushed, a rotor 2 rotatably supported in the casing and to which one or more are pivotally or rigidly attached substantially radial hammers 3, drive means 5 for the rotor and a lower grid 12 through which the material reduced to fairly small fragments can pass. Compared to the hammer mills of the prior art, the mill according to the invention is improved in that the lower grid 12 is composed of a disc or roller screen comprising a plurality of shafts, said shafts 4 being arranged so that the most centrally located trees are placed lower than the side most trees. (CF DRAWING IN BOPI)

Description

The present invention relates to a grinder & hammers for crushing

  hard and soft substances, which comprises a box, a feed opening for the materials to be ground, a rotor rotatably supported in the box and to which are fixed pivotally a

  or several substantially radial hammers, a trainer

  for the rotor, and a lower grid across the-

  what can pass matter that has been reduced to fragments

of sufficiently small size.

  The function for which such a hammer mill is used is to crush hard and soft substances to a desired maximum fragment size and to separate non-crushable objects from the milled material in solid fuel and waste treatments.

  The most common areas of application are the bro-

  minerals, industrial and domestic wastes and

of coal.

  A conventional hammer mill comprises a rotor,

  radial hammers are fixed, a bridge with a serrated blade

  sideboard, and a lower grid that covers

  completely or partially the lower side of the chamber

grinding.

  The lower grid is usually constituted

  transverse bars, the interval between them

  denoting the size of the largest fragments of

  crushed, or a perforated plate whose diameter

  Forests defines the size of the largest fragments.

  In a hammer mill with an inferior grid

  only covers a part of the bottom of the room, there is no effective separation of objects at all

  not crushed. Uncrushed pieces of excessive size

  exit from the chamber through an opening after

Grid.

  In a hammer mill with an inferior grid

  the entire bottom of the grinding chamber, a separation of rejects or refusal is necessary. One solution is to provide a spring-loaded tilting flap, located above the blade bridge, which opens when the hammers push an unmilled body along the top surface of the knives and against said tilting flap. Another solution is to provide a refusal pocket placed opposite the blade bridge on the other side of the rotor. After passing on the lower grid, the unmilled object is thrown against the roof of the refusal pocket

  and fall from that roof into the refusal pocket.

  Hammer mills according to the prior art

  However, they suffer from the inconvenience of blocking

  the lower mistletoe occurs when crushing materials

  light and tender, for example peat moss.

  The kinetic energy of such a light material is too much

  low for the material that has been projected into the grill.

  the by a friction and adhesion effect comes off and

flows correctly.

  The disadvantage of the separation of discharges or

  fuse by means of a tilting flap is that openings

  the lower grate of the crusher must have dimensions

  equal to the size of the largest body that can work

  pour or cross the blade bridge. In any other case, a non-crushable object that has entered the grinder turns

  with the hammers in the grinding chamber and may

  to mage the structure. On the other hand, if the lower grid has wider spacings, the size of the fragments of

  the material leaving the mill is large.

  The disadvantage of grinders with refuse pockets, of the type currently existing, is that, as a result of excessive temporary feeds, the refusal bag

  fills up with material to be grinded and therefore stops functioning

  until the bag is empty.

  The object of the present invention is to provide a hammer mill which is free of the disadvantages mentioned and which therefore provides a safer and more efficient service. The hammer mill according to the invention is characterized in that the lower grid is composed of a disk or roller screen with a plurality of shafts, these shafts being arranged so that the

  central trees are placed lower than the lateral trees

  ral. An advantageous embodiment of the hammer mill according to the invention is characterized in that each shaft of the lower grid is at the same distance from the axis of the rotor, so that all the trees are situated on an arc of a circle. having as center axis

of the rotor.

  Another advantageous embodiment of the invention

  The invention is characterized in that the shafts of the lower grid are rotatably arranged, and that the distance from these shafts to the axis of the rotor is

  provided that, when the rotor is rotating, the ends

  hammers maintain the lower grid in

a state of cleanliness.

  A more advantageous mode of realization of the in-

  vention is characterized in that the dimension of the largest body passing through the mill is adjustable by

  modification of the separation limits of the constituent screen

killing the lower grid.

  A hammer mill of this type provides

  many advantages over grinding mills according to the

  including jamming when fibrous or sticky fiber-containing waste is degraded, wet charcoal, and copiously mixed with clay, and

  fuels containing peat. The crusher is not

  only bodies that are smaller than the size

  the desired maximum fragment size. In addition, the

  protects non-crushable bodies, exceeding the maximum dimension

  desired fragment, of which are crumbly, lndepen-

  the design of the blade bridge. An application

  special, which can not be achieved with a shredder.

  usual, is the treatment of coal containing abundant country rock, in which coal contains

  in the feed is milled at a peripheral speed of

  weakly rock, so that the harder rock is not crushed and instead is projected into the refusal pocket and is evacuated by spilling the plane of the hammer.

screen.

  Among other advantages, mention may be made of

  the refusal bag does not fill and that

  can be directly sent on a denial carrier. In addition, there is no crushed material entrained

  with discharges, for example during conditions of over-

  temporary charge. In addition, the pieces of too large

  dimension are overwritten at some point when they are

  the roof of the refusal pocket, so that the proportion

  too large pieces in refusals is reduced.

  When the inner grid consists of a

  roller screen, the accumulation of a very

  on the surface of the rollers, generating an increasing layer, can be prevented by adjusting the position of the rotor relative to the rollers so that the end of the hammer passes very close to the surface of the rollers;

  which detaches at the same time any matter adhering to the

  face of the rollers. When the bottom grid consists of a disc screen, the screen stuffing can be prevented by positioning the rotor so that the ends of the hammers penetrate the gap between the discs, so that the hammers clean the screen when

the rotor rotates.

  In addition to the foregoing, the invention also includes other arrangements which will emerge from

the following description.

  The invention will be better understood by means of the

  description below, which refers to the drawings

  Annexes in which: Figure 1 shows, schematically and in section, a hammer mill according to the invention and the refusal pocket associated with this mill, and Figure 2 is a section along the line II-II

of Figure 1.

  It should be understood, however, that these drawings and the corresponding descriptive parts are given solely by way of illustration of the object of the invention, of which they in no way constitute a limitation.

  FIG. 1 represents a hammer mill

  carrying a lower grid and a rejection or rejection sorting device, this crusher comprising a caisson 1

  wherein a rotor 2 is rotatably supported.

  Hammers 3 are attached to the rotor. The lower part of the mill consists of a set of screens 12 with rollers or disks, serving as a lower gate, and which is constructed in a circular arc configuration. This grid comprises a plurality of screen rollers placed side by side and preferably rotatably arranged. The rotor is driven, as shown in the figure, by a motor 5 which is usually a motor

  but which can also be a

  internal combustion, a steam engine or equivalent.

  The shafts 4 of the roller screen or disc

  in the lower part of the crusher are supported

  rotating part in the crusher box 1 and the trees

  sieves are rotated by a 6

  carrying its own motor, or by a drive drawing its energy on the drive 5. The base of the refusal pocket 10, which is constituted by a chamber, is formed

  by a screen, preferably a roller screen or a screen

  7, whose rollers are rotated by a drive 8 having its own motor, or by a drive which is common to the roller or disk screen of the lower part of the mill, or by a drive. drawing energy from the training

5.

  The shafts 4 of the roller or disk screen of the lower part of the mill may turn clockwise or in the opposite direction. The shafts of the roller screen or disc of the refuse bag 10 turn clockwise, so that they carry the material, which has been projected

  on the screen, outside the refusal pocket. The movements

  rotating rollers or disc screens are interconnected by means of a chain, gears,

  toothed belt or other belt drive.

  Each tree can also be trained by its own

  drive, for example by a hydraulic motor.

  The material to be ground is introduced above the rotor 2 of the mill. The material fragmented by the hammers is screened or screened through the lower grid 12 and the oversize pieces are subject to

repeated impacts.

  The unmilled objects are thrown against the roof of the refusal bag 10 and fall from this roof onto the rejection screen 7. The oversize and unmilled objects from the material that has entered the refusal pocket are removed. as overflow from the sieve to

  refusal. The size of the largest body is

  grinder, by setting the separation limit

  the bottom grid and the reject screen.

  As is apparent from the foregoing, the

  tion is not limited to those of its modes of

  implementation and application that have been described more explicitly; it embraces all the contrary

  variants that may come to the mind of the technician -

  in this regard without departing from the scope and scope of the present invention. For example, a fixed gate hammer mill may also be equipped with a reject separator as taught by the invention. The rotating set of grids can also be made in a grinding mill.

  hammers with vertical shaft. In this case, the bro-

  yage is defined by vertical shafts of the rolling screen.

  discs, which rotate when the grinder is in

  service. In this case, the material to be grinded must not be

hold non-crushable items.

6) FRENCH REPUBLIC

NATIONAL INSTITUTE

OF INDUSTRIAL PROPERTY

PARIS

2,594,050

  This issue did not result in any publication o0 or the N an I

Claims (4)

claims   1. Hammer mill for grinding hard and soft substances, comprising a box (1), a feed opening (11) for the material to be ground, a rotor (2) rotatably supported in the box and to which are attached pivotally or rigidly one or more substantially radial hammers (3), drive means (5) for the rotor and a lower grid (12) through which the reduced material can be passed into relatively small fragments, characterized in that the lower grid (12) is composed of a disk or roller screen comprising a plurality of shafts, said shafts (4) being arranged so that the most centrally located shafts are placed   lower than most trees on the sides.   2. Hammer mill according to claim 1,   characterized in that each shaft (4) of the lower grid   upper (12) is also distant from the axis of the rotor (12), so that all the trees are on the same arc   circle centered on the axis of the rotor (2).   3. Hammer mill according to claim 1   or 2, characterized in that the shafts (4) of the grid   (12) are rotatably arranged, and that the distance from the shafts (4) to the axis of the rotor (2) is provided so that when the rotor rotates, the   ends of the hammers (3) clean the lower grid.   4. Hammer mill according to any one of   Claims 1 to 3, characterized in that it is possible   set the size of the largest body that passes through the mill, adjusting the separation limits of the screen   constituted by the lower grid (12).