DE2122706A1 - Hard crusher - Google Patents

Description

Applicant; Dominion Engineering Works, Limited, Toronto , Ontario, Canada

Hard crusher

The invention relates to a hard grinding machine, in particular Devices for controlling the delivery of finely ground grist from mills.

When using hard crushers the efficiency of operation is of a satisfactory fume cupboard of the grist from the grinder. In the expansion of mills to achieve an improved construction and increased Economy is the practically achievable advantage of considerably enlarging the mill depending on a satisfactory one Deduction of the regrind in order to keep the required power for the drive within tolerable limits.

The withdrawal of grist from upstream mills usually requires a secondary screening process outside the mill the grinding process in the mill, whereby material with an impermissibly large grain size is returned to the entrance of the mill, or as Feed material is fed to another mill. It is therefore the object of the invention to address difficulties of the type mentioned as possible largely to be avoided.

ORiSiMAL

109848/1339

The invention provides an extraction device in which the annular discharge zone of the mill is inclined Lifters are provided to facilitate the unloading of material from the mill. In connection with the inclined lifters in the mill an inner sieve device is provided to remove ground material from semi-ground Separate well and unload the finely chopped material from the mill while the finely chopped material is in the mill is returned to the grinding section for another Allow shredding.

The invention is applicable to both dry mills and wet mills, as well as roller mills, ball mills and semi-autogenous mills or autogenous mills.

A mill according to the invention has a rotatable housing, at least a crushing zone, a feed device at one end of the housing, separating devices arranged in the housing at an axial distance from the feed device, around an annular To form siphon zone adjacent to the comminution zone, the grist classifying sieve roast between the zones to a To allow passage of suitably crushed grist to the lift zone from the grinding zone, as well as a number of inclined Lifters in the lift zone, each of which has a portion of its quantity in an inclined, non-radial relationship inward of the outer periphery of the lift zone extends, and means for unloading grist from the lift zone, which in the Operation of the mill from the grinding zone arises and is applied by the rotation of the mill because of the inclination of the lifters.

A mill according to the invention also has a lifting zone which is provided axially separated from a grinding zone, with a number of inclined lifters extending outwardly around the lift zone in a number of equals To subdivide non-radial segments of the lift zone, a primary screen wall, which at least part of the lift zone from the Grinding zone separates to allow a passage to the siphon zone for grinding material suitable for comminution of partially comminuted grist to enable box-shaped walls in the siphon zone to subdivide at least some of the segments of the siphon zone into a »fine crushed and recycled into a fraction, secondary

103843/1339

—3—

Sieve walls, which form part of the box-shaped walls, around a Fraction of a secondary size of the primary size of that to be returned Share to the finely ground share to enable a discharge device in conjunction with the relevant Sub-segments of the siphon zone for receiving regrind of secondary size thereof, as well as a return device in connection with the returning segment parts and the grinding zone of the mill to return the part of the primary fraction which is coarser than the second fraction is so that further comminution takes place in the grinding zone.

Arched jacks are preferably used. However, straight lifters can also be used that extend outwards from the radial direction are inclined to face in the direction of rotation. If such a sloping jack is arched, straight or is formed in a suitable combination, the result is an extended period of time for the transport of the ground material, with the material slides along the cut surface of the lifter in a controlled manner instead of rising radially inward as with radial lifters.

The improved operation of inclined lifters instead of radial ones Lifting is at least partially due to the scooping effect of the lifters when they pass through the zone in question, as well as the increased effective length of the lifter surface immersed in the zone due to the effective non-radial component of the lifter length. Furthermore, there is an earlier initial sliding of the grist in the unloading direction inward from the top of the lifter, because of the tilt of the lifter through the angle of inclination when placed closer to the zone concerned. The available unloading time is extended accordingly and improved transport characteristics are achieved.

The main characteristics of a hard crusher according to the invention, which has a large diameter, are therefore to be seen in that curved jacks provide an improved radial one Allow transport of regrind after it has passed through primary sieve grates, and that secondary sieve grates in the form of Box sections combined with the curved surfaces of the lifters are to be able to separate completely comminuted grinding

109848/1339

good to allow while semi-crushed grist to the grinding zone is returned.

The invention is to be explained in more detail with the aid of the drawing. Show it:

1 shows a longitudinal section through a hard crushing machine according to the invention;

Fig. 2 is a schematic view of a siphon zone according to the invention; and

FIG. 3 is an enlarged partial view of a lifter in FIG. 2.

The housing 10 of the mill, shown in longitudinal section in FIG. 1, is arranged to be rotatable about a horizontal axis. At the ends 11, 12 of the housing are in a known manner hollow drums for Loading and unloading of the mill provided.

The inclined walls 15, 16 of the mill are provided with wedge bars 17 which carry along the quasi-liquid contents of the mill. They are lined with rubber to prevent abrasion.

An annular partition separates the discharge side of the mill 20 the grinding zone 21 from the lifting zone 22. A number of primary sieve roasters 23, 25 in the partition 20, which are also shown in FIG Fig. 2 are shown, allow the passage from the grinding zone to the lift zone, if the ground material is appropriately comminuted, so that ground material crushed to the desired mesh size can pass through together with medium grain size ground material.

As can be seen from Figure 2, the lifters 30 divide the annular lift zone 22 into a number of segments 33. In each the segments 33 in the illustrated embodiment, a so-called rubber box 35 is provided, the surface of which as secondary screen grate 36 is formed. The wedge bars 17 are omitted for the sake of clarity.

The inwardly extending boxes 35 extend along the full axial extent of the lifters 30 the radial outer end. They have a reduced axial width and an increased peripheral dimension at the mouthpieces 37 µm allow an annular discharge through adjacent slots. Part of the spaces 33 between the lifters is left free axially adjacent to it in order to allow the passage of large

1098A8 / 1339

To allow berem grist that is too large for a passage through the secondary grate 36.

With a suitable drum division, the grist can be made more secondary Size and smaller grist pass in the axial direction through the drum 12 and is outside the mill 10 for another recovery accumulated. The regrind of the primary size and smaller material is divided into the Mill returned for further grinding.

While the assembled jacks with boxes 35 are of curved double-walled construction, others may as well Find forms of inclined lifters use.

The boxes 35 are made of hard rubber, plastic or other abrasion-resistant material, or are lined with such materials and covered.

In operation, earlier unloading of regrind leads to earlier unloading after leaving the regrind sump the lifting zone. This reduces the speed of the discharge suitably so as to prevent the material from being thrown against the rear side to reduce or prevent the previous lifter. In particular, the work against the mill is reduced, due to of the reduced lifting head, so that there is a reduced power requirement, the size of the mills can be reduced or the capacity of the mill can be increased accordingly.

Although the embodiment of the invention relates to a mill with a single grinding zone, the invention also applies to mills can be used with several grinding zones. It is also possible to use non-radial elongated lifters, which are related to are arranged in the shape of a chord on the grinding zone.

Claims

ORiGINAL INSPECTED

109848/1339

Claims (9)

Claims 1. Method of operating a hard grinding machine with a Housing rotatable about a horizontal axis with at least one grinding zone and at least one adjoining in the axial direction Transmission zone, characterized that a part of the ground material of predetermined grain size from the grinding zone to the transfer zone primarily to a radially outer part of which is transported relative zu.der axis of rotation of the machine that the radially outermost part initially accelerates inward is, when this is close to the material level in the grinding zone, inclined in one direction relative to the axis of rotation to the direction of rotation in such a sense that there is a slight initial acceleration that that which is inward Movement is maintained and that this part is discharged from the transfer zone. 2. The method according to claim 1, characterized in that that the predetermined portion is again divided into a first sub-portion of smaller grain size and a second sub-portion which represents the residue of the predetermined portion that the first sub-portion in the axial direction out of the machine is discharged, and that the second sub-fraction is transported into the grinding zone in order to carry out further comminution. 3. The method according to claim 2, characterized in that that the predetermined portion is transported inward relative to the axis of rotation over a screen surface in the transfer zone to perform a classification. 4. Hard crushing machine to carry out the process according to One of the preceding claims, with a rotatably mounted housing, with at least one grinding zone, with a feed device at one end of the housing, thus marked "indicates that a separating device is provided in the housing 109848/1339 originally inspected can be seen, which is separated in the axial direction from the feed device is to have an annular lift zone axially adjacent to the To form grinding zone that a screen device is arranged between the zones, the passage of grist corresponding Size to the lift zone from the grinding zone enables a number of inclined lifters (30) in the lift zone to each have a portion thereof Have length extending in an inclined, non-radial relationship inwardly from the outer periphery of the lift zone by one to allow initial inward acceleration according to the inclination of the jack in question, and that a discharge device is provided for unloading regrind to which regrind is transported from the grinding zone when the machine is in operation when the respective jacks are inclined upwards. 5. hard crushing machine according to claim 4, characterized g e identifier Inet that the screen device comprises a primary screen device to the passage of a primary Share of crushed grist to the siphon zone to allow at least some of the inclined siphon box-shaped wall parts in the siphon zone to divide the zone in question into a primary and a secondary zone, that a secondary Screen device allows a secondary portion of comminuted ground material to enter the secondary zone, which has a smaller grain size than the primary proportion that a discharge device communicates with the secondary zone to discharge the secondary portion received, and that one Return device with the primary siphon zones and the grinding zone is in connection in order to transport the primary portion of the ground material back for further comminution, so that in the machine a classification of the grist can be carried out. 6. Hard crushing machine according to claim 5, characterized in that that the lifters extend in a forwardly curved relationship to the periphery of the lift zone, relative to the direction of rotation of the machine, and that the residue of the primary portion of the grist is transported through the machine again will. 109848/1339 7. Hard crushing machine according to claim 6, characterized in that that the discharge device contains an axially outer ring body / the one with the secondary zones is in communication to receive the secondary portion of the grist, and that an axially internal discharge means is provided to collect the residue of the primary portion of the grist and return it to the grinding zone. 8. hard crushing machine according to claim 4, 5 or 6, characterized in that it is an autogenous Machine is. 9. Hard crushing machine according to claim 4, characterized in that a number of elongated boxes it is provided in the lifting zone that each box is arranged between curved lifters and extends along part of the extends curved path, which is given by the lifter in question, that the grating is formed such that fine crushed grist enters the box concerned, and that a discharge device at the radially inner end thereof is provided to remove finely chopped grist from the machine. _t 10. Hard crushing machine according to claim 9, characterized ge ™ indicates that the siphon zone is divided by curved siphon into small siphon zones, that the elongated boxes carry the grate for the finely crushed grist on their concave surface, and that the axial dimension of the boxes the radially inner discharge end is reduced in order to allow an exit from the primary zones. 1098 4 8/1339 Blank page