NZ551486A - Milling apparatus with outboard bearings and agitators on shaft - Google Patents

Abstract

Ball milling apparatus of an at least substantially horizontal agitator shafted kind in an at least substantially horizontal chamber (eg, for use as a mechanochemical reactor), wherein there is an end plate that closes the at least substantially horizontally aligned cylinder and it is through that end plate that the shaft passes, a first sealing assembly of the end plate (i.e. supported directly or indirectly from the end plate) that provides at least a substantial seal of the shaft from the chamber, a second sealing assembly to the shaft spaced outwardly from the first sealing assembly, a bearing for the shaft, and journalled on the shaft, further outwardly than the second sealing assembly, and a support for the second sealing assembly and bearing from the end plate.

Description

551486 NEW ZEALAND PATENTS ACT, 1953 X \ No: 551486 Date: 21 November 2006 COMPLETE SPECIFICATION MILLING APPARATUS We, ENVIRONMENTAL DECONTAMINATION LIMITED, a company duly incorporated under the laws of New Zealand 139 Cryers Road, East Tamaki, Manukau 2013, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: 551486 There are many instances where milling apparatus is used.

One instance is in reducing the size of materials from a first range of particulate sizes to a second size of particulate sizes.

Another instance is where milling apparatus is used to ensure mechanochemical reaction.

We have determined that an appropriate form of milling apparatus for any such purpose but with relatively low energy input requirements, reliability, wear resistance (but with easy reconditioning capabilities), etc, is a horizontal or near horizontal (hereafter "horizontal") shafted ball mill (irrespective of whether the impact members are true balls or are barrels or the like).

The present invention is directed to options for such apparatus and its usage. a housing defining or to define a horizontally extending chamber bounded at each end by an end plate, said chamber including an inlet and a drop out outlet port, a bearing for a shaft externally of each said end plate and mounted directly or indirectly to said end plate, a shaft rotatable within the chamber and supported at each end by a said bearings, agitator forms rotatable with the shaft in the chamber, and impact masses to be agitated by the agitator forms when the shaft rotates, Such an arrangement allows the bearing and its lubricants to be (i) sealed externally of the chamber, (ii) to be protected in a journal-box protected by one or more seal assembly from contamination from the chamber, and/or (iii) to have a lower operating temperature than in the chamber.

There are preferably two end plates of the housing, each preferably substantially parallel to the other.

Preferably at least one, if not both, end plates is detachable from the cylinder or the like of the housing eg, by detachment of bolts from a flange to flange fitting.

Preferably the bearing is set out from the end plate but is carried by a support structure (in a journal-box assembly) fixed to the end plate. Preferably that support structure is in part skeletal.

Preferably there is an at least substantially similar mounting of a shaft supporting beating externally of each end plate or externally of the chamber at each end region of the shaft.

In less desired forms of the present invention, one end plate can be welded or otherwise be integral with the cylinder.

In one aspect the invention is milling apparatus comprising or including (and optionally a drive to the shaft).

Preferably the shaft rotates parallel to or coaxially with the cylindrical chamber axis. 551486 Preferably there is a seal to the shaft from and/or outside of the end plate thereby providing a first sealed zone.

Preferably there is a second sealed zone outwardly of the first sealed zone yet inwardly of said beating. Preferably that second sealed zone involves a sealing of the bearing to the shaft eg, in conjunction with a closed bore about the bearing.

Preferably said second sealed zone has the effect of protecting the bearing against contamination that might pass through said first sealed zone.

Preferably an overcap attaches to the end plate thereby sealed zone(s) to seal the zone and bearing to said end plate.

Preferably one end of the shaft is adapted to receive a drive eg, directly or indirectly from an electric motor or other mechanical drive.

Preferably the shaft has agitators keyed thereto.

Preferably the keying is not reliant upon a key way but rather relies upon a non-circular or non-rotational profile of the shaft to which the agitators complement eg, preferably there is a hexagonal or other faceted profile to which the agitators match.

Preferably the paddles are arrayed so as to be staggered with respect to its neighbours about the shaft.

Preferably said housing has an inlet from above.

Preferably said inlet from above is non circumferential of the cylindrical chamber but can be so if desired.

Preferably there is a drop out outlet port for fine material.

Preferably the drop out port or oudet port is not disposed directly below the inlet but may be central or at one end on the shaft axis or indeed can be circumferential of the agitators.

Preferably the outlet port is provided with a grate or other forms to keep the balls within the chamber.

Preferably there is an oudet preferably from above for vapours and this oudet preferably feeds to a vapour treatment and/or capturing arrangement.

Preferably both the inlet and oudet ports, or one of them, includes a knife or other valve to control its opening.

Preferably said agitators have a clearance from the (preferably cylindrical) housing sufficient to allow about three balls spacing between the distal region of each agitator and the nearest inner surface of the chamber.

Preferably said balls are of a metal such as steel (eg, stainless steel, mild steel or other steel). \ 3 551486 Preferably a conical or other structure is provided from the housing and/or the shaft to provide a component of directionality for in feed of material that drops from said inlet into the chamber.

Preferably said conical form is frustoconnical or otherwise but is directed from one end region of the chamber to the shaft below the inlet.

Preferably the arrangement is substantially hereinafter described with reference to any one or more of the accompanying drawings.

In another aspect the invention consists in, ball milling apparatus of an at least substantially horizontal agitator shafted kind in an at least substantially horizontal chamber, wherein there is an end plate that closes the at least substantially horizontally aligned cylinder and it is through that end plate that the shaft passes, a first sealing assembly of the end plate (i.e. supported directly or indirectly from the end plate) that provides at least a substantial seal of the shaft from the chamber, a second sealing assembly to the shaft spaced outwardly from the first sealing assembly (eg, of a journal-box of a bearing), a bearing for the shaft (and journalled on the shaft) further outwardly than the second sealing assembly (eg, in the journal-box), and a support for the second sealing assembly and bearing from the end plate (eg, the journal-box as assembly is fixed to or connects to the end plate).

Preferably an end cap substantially seals about the first sealing assembly, the second sealing assembly, the bearing and the support of the second sealing assembly and bearing.

The present invention consists in the use of milling apparatus of any of the kinds previously described where the bearing, at least one end region of the shaft, operates at a temperature below that of the chamber in which impacts take place as a consequence of the agitation of the balls or other impact masses.

In a further aspect the invention consists in the use of milling apparatus as aforesaid where there is an over capping of a bearing at each end region of the shaft that carries the agitator forms, the bearings being isolated from contamination from the chamber by at least one sealing assembly externally of the impact chamber itself.

In still a further aspect the invention consists in the use in a mechanochemical reaction of milling apparatus of any of the kind previously described.

In yet a further aspect the present invention consists in the use for the purpose of reducing the size of material of milling apparatus of any of thejand-previously described. 551486 In a further aspect the invention consists in milling apparatus substantially as hereinafter described with reference to any one or more of the accompanying drawings.

In yet a further aspect the present invention consists in a method of ball milling involving apparatus as aforesaid and/or a use of aforesaid or a method substantially as hereinafter described with reference to any one or more of the accompanying drawings.

As used herein the term "and/or" means "and" or "or", or both.

As used herein the term "(s)" following a noun includes, as might be appropriate, the singular or plural forms of that noun.

As used herein "journal box" is non specific as to the form or configuration of the enclosure of the bearing assembly.

A preferred form of the present invention will now be described with reference to the accompany drawings in which Figure 1 is a drawing of a preferred form of apparatus in accordance with the present invention showing in bold a drive motor (an electric motor) coupled to a shaft end, the shaft passing through a cylindrical end plates bolted to flanges of the cylindrical, the chamber housing to receive the charge to be impacted by balls or other impact items (not shown) to be agitated by the paddles shown outstanding from the shaft, the inlet for material to be impacted being from the hopper shown into a zone at one end of the shaft within the impact chamber, there being a frustoconnical form clear of paddle or other agitator forms but flaring to such forms to direct the material to the right, Figure 2 is a more detailed view of the housing defined chamber showing a knife gate valve (as the cross) to control in feed from above via the inlet and through the flare of the frustoconnical form into the chamber and a knife gate valve to control out take from below the chamber, there being in addition a vent outlet preferably via an absorbing medium (fibrous and/or activated carbon) into a vapour capture regime preferably controlled by appropriate valves, Figure 3 is a reduced scale view of the apparatus of Figure 3 but from the direction AA with respect to Figure 2, Figure 4 is a close up of one end (the motor coupled end) of the shaft showing externally of the shaft and its in chamber carried agitator arm, paddle or like forms, a labyrinth type seal to the shaft (as a first sealed assembly) and outwardly therefrom (i.e. further to the left) a further sealed assembly to the shaft from a closed bore or through bore outside of which (but in the bore of which) is provided the bearing for the shaft, the bearing being housed in the bore along with the second sealing assembly on the rotational axis and supported back to the end plate of the casing, 551486 Figufe 5 is one preferred form of an agitator component in accordance with the present invention, Figure 5B is another preferred form of such an agitator, Figure 6 is another view of such a component, the components of Figures 5 and 6 preferably having a helical centre adapted to non-rotationally fit in sequenced stagger about the correspondingly hexagonal shaft and Figure 6B is of the embodiment of Figure 5A.

In the preferred form of the present invention there is provided a hatched container 1 in which the apparatus 2 of the present invention is at least substantially sealably located.

Shown is a shaft 3 coupled by a coupling 4 to a motor 50. This has the effect of rotating the agitator forms 5 carried on the hexagonal shaft 3 about the rotational axis provided by the end bearings 6 (eg, preferably roller-bearings in a journal-box assembly) at each end region of the shaft 3.

Each bearing 6 as will be described in more detail with respect to Figure 4 is supported from an end plate 7.

Figure 4 does not show (for convenience) the movement encouraging and space constricting frustoconnical member 8 through which gate valve 9 from an in feed (preferably sealed) hopper 10 can drop material through the flare of the frustoconnical form 8 as shown by the arrow in Figure 2.

The shaft 3 carries a plurality of forms 11 preferably each substantially staggered with respect to its neighbour around the preferred hexagonal or other non-rotational shape of the shaft (over that region) so as to act as a drive on complementary forms eg, of a wear resistant metal (eg, cast steels)or other material. See Figures 5 and 6 described hereinafter.

Figure 4 shows the bearing 6 outwardly of the second sealing assembly 12 which seals with appropriate rings, o-rings or other members the journal-box assembly to the shaft at that zone i.e. the "bore" of the joumal-box like member 13 that supports the bearing 6 provides an appropriate rotational axis for the bearing. Other seals or the like members (third seal or seal assemblies 14 can be provided outwardly of the bearing 6 but within the member 13). As shown a cap 15 can be fitted as a part thereof. Such a cap 15 in connecting to the journal-box member 13 by appropriate bolting. The seal assembly 12 and its members 13 and 15 are fixed to the plate 16 in turn fixed to end plate 7. Member 17 is preferably fixed by a flange 18 as part of an overcap assembly also to the end plate 7. The plate 16 however is preferably fully supported (i.e. when the overcap is removed) by the in part skeletal structure 19 welded or otherwise affixed at the region 20 to the end plate 7. 551486 The end plate 7 itself is preferably bolted to a flange 21 of the circular housing 22. Housing 22 has the inlet opening 23 from the sealed hopper 24, a vent tube 25 also upwardly therefrom and a downward grated oudet 26 to an appropriate collection zone 27. Disposed in the conduit of vapour vent 25 can be appropriate fibreglass or other fibrous materials feeding to a collection apparatus which can include, by way of example, activated carbon.

It is found that the paddle form shown as in Figures 5 and 6, each preferably with a helical form to match that of the central region of the shaft, can be rotated away from the in feed inlet 23 and appropriately comminute with ball agitation the materials from the starting size to an end size or subject the materials to an impact of the balls or other impact shapes.

The gap between the distal regions of the paddles 5 to the cylindrical casing 22 is preferably about three times the ball diameter so as to keep energy usage to an optimal minimum. A greater distance tends to leave material caking on the exterior or slumping out of contact. A lesser distance requires a much greater energy requirement.

The arrangement as shown in the aforementioned drawings lends itself for use in a battery of such apparatus, one feeding down to another in columns or otherwise as disclosed in our New Zealand patent application no 545960 (eg, for soil remediation as in our New Zealand patent application no 545961 and our W00183038 and our WOOl 83127) hereinafter included by way of reference.

A person skilled in the art will appreciate how the present invention provides an alternative to existing regimes.

The bearings with such an arrangement we find operate at a temperature of, say, about 160°C despite the temperature at the surface of the cylindrical housing being about, say, 400°C. This leads to lubricant/bearing longevity.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art. 551486

Claims (39)

WHAT WE CLAIM IS

1. Milling apparatus comprising or including a housing defining or to define a horizontally extending chamber bounded at each end by an end plate, said chamber including an inlet and a drop out oudet port, a bearing for a shaft externally of each said end plate and mounted directly or indirectiy to said end plate, a shaft rotatable within the chamber and supported at each end by a said bearings, agitator forms rotatable with the shaft in the chamber, and impact masses to be agitated by the agitator forms when the shaft rotates.

2. Apparatus of claim 1 wherein the bearing is set out from the end plate but is carried by a support structure fixed or engaged to the end plate.

3. Apparatus of claim 2 wherein the support structure is in part skeletal.

4. Apparatus of claim 2 or 3 wherein said support structure is in a journal box assembly.

5. Apparatus of any one of the preceding claims wherein the housing is defined in part by an at least substantially cylindrical member closed at one end, or at each end, by the or an end plate.

6. Apparatus of claim 5 wherein there are two end plates with the shaft being bearing mounted outside each end plate but directly or indirectly from each end plate.

7. Apparatus of claim 6 wherein at least one end plate is detachable from the cylindrical member by detachment of bolts from a flange to flange fitting.

8. Apparatus of claim 6 or 7 wherein there is an at least substantially similar mounting of the shaft supporting bearing externally of each end plate.

9. Apparatus of any one of the preceding claims wherein there is a drive to the shaft directly or indirectly from an electric motor or other mechanical drive.

10. Apparatus of any one of the preceding claims wherein there is a seal to the shaft from and/or outside of the, or each, end plate thereby providing, or contributing to, a first sealed zone.

11. Apparatus of claim 10 wherein there is a second sealed zone outwardly of the first sealed zone yet inwardly of said bearing.

12. Apparatus of claim 11 wherein that second sealed zone involves a sealing of the bearing to the shaft in conjunction with a closed bore about the bearing.

13. Apparatus of claim 11 or 12 wherein said second sealed zone has the effect of protecting the bearing against contamination that might pass through said first sealed zone.

14. Apparatus of any one of the preceding claims wherein there is an overcap which attaches to the end plate thereby to seal a zone and bearing to-ssfietjqjri 1 s*;%;/ V/ °;I \ 3 ®;551486;-9-;

15. Apparatus of any one of the preceding claims wherein the shaft rotates on a substantially horizontal axis.;

16. Apparatus of any one of the preceding claims wherein the shaft rotates parallel to or coaxially with the axis at least of a substantially cylindrical chamber defining housing or part thereof.;

17. Apparatus of any one of the preceding claims wherein the shaft has agitators keyed thereto.;

18. Apparatus of claim 17 wherein there is keying of the agitators to the shaft and said keying is not reliant upon a key way but rather relies upon a non-circular or non-rotational profile of the shaft to which the agitators complement.;

19. Apparatus of any one of the preceding claims wherein the agitators are arrayed so as to be staggered with respect to its neighbours about the shaft.;

20. Apparatus of any one of the preceding claims wherein the shaft rotates on a substantially horizontal rotational axis and said housing has an inlet from above.;

21. Apparatus of claim 20 wherein there is a drop out outlet port from said housing for fine material.;

22. Apparatus of claim 21 wherein the drop out port oudet port is not disposed directly below the inlet but may be central or at one end on the shaft axis or indeed can be circumferential of the agitators.;

23. Apparatus of claim 21 or 22 wherein the oudet port is provided with a grate or other forms to keep the balls within the chamber.;

24. Apparatus of claim 21, 22 or 23 wherein both the inlet and oudet ports, or one of them, includes a knife gate valve or other valve to control its opening.;

25. Apparatus of any one of the preceding claims wherein there is an oudet from the housing for vapours and this oudet feeds to a vapour treatment and/or capturing arrangement.;

26. Apparatus of any one of the preceding claims wherein said balls are at least initially of the same size and the agitators have a clearance from the housing sufficient to allow a clearance of about three ball initial diameters between the distal region of each agitator and the nearest inner surface of the chamber.;

27. Apparatus of any one of the preceding claims wherein said balls are of a metal.;

28. Apparatus of claim 20 wherein there is a conical or other structure provided from the housing and/or the shaft to provide a component of directionality for in feed of material that drops from said inlet into the chamber.;

29. Apparatus of claim 28 wherein said conical form is frustoconnical or otherwise but is directed from one end region of the chamber to the s;551486;-10-;

30. Ball milling apparatus of an at least substantially horizontal agitator shafted kind in an at least substantially horizontal chamber, wherein there is end plates that close the at least substantially horizontally aligned cylinder and it is through these end plates that the shaft passes,;a first sealing assembly of the end plates (i.e. supported directly or indirectly from the end plate) that provides at least a substantial seal of the shaft from the chamber,;a second sealing assembly to the shaft spaced outwardly from the first sealing assembly, a bearing for the shaft, and journalled on the shaft, further outwardly than the second sealing assembly, and a support for the second sealing assembly and bearing from the end plates.;

31. Apparatus of claim 30 wherein the first sealing assembly is a journal box.;

32. Apparatus of claim 30 or 31 wherein there is an end cap which substantially seals about the first sealing assembly, the second sealing assembly, the bearing and the support of the second sealing assembly and bearing.;

33. Apparatus of any one of the preceding claims wherein the arrangement is substantially hereinbefore described with reference to any one or more of the accompanying drawings.;

34. The use of apparatus of any one of the preceding claims where the bearing, at at least one end region of the shaft, operates at a temperature below that of the chamber in which impacts take place as a consequence of the agitation of the balls or other impact masses.;

35. The use of apparatus of any one of claims 1 to 33 where there is an over capping of a beating at each end region of the shaft that carries the agitator forms, the bearings being isolated from contamination from the chamber by at least one sealing assembly externally of the impact chamber itself.;

36. The use substantially as herein described in a mechanochemical reaction of apparatus of any one of claims 1 to 33.;

37. The use substantially as herein described for the purpose of reducing the size of material of milling apparatus of any one of claims 1 to 33.;

38. Apparatus of or for a mechanochemical treatment facility when substantially as hereinbefore described with reference to any one or more of the accompanying drawings.;

39. A method of ball milling involving apparatus of any one of claims 1 to 33 and 38 and/or a use of any one of claims 34 to 37 substantially as hereinbefore described with reference to any one or more of the accompanying drawings.;DATED THIS S 2^*