ZA200503874B

ZA200503874B - Dissolving station

Info

Publication number: ZA200503874B
Application number: ZA200503874A
Authority: ZA
Inventors: Heinrich Mueller; Werner Ries
Original assignee: Mueller & Co Aufbereitungstech
Priority date: 2002-12-06
Filing date: 2005-05-13
Publication date: 2006-08-30
Also published as: EP1567275B1; EP1567275A1; ES2383264T3; DE20218919U1; WO2004052546A1; ATE550100T1; AU2003292988A1

Abstract

Disclosed is a dissolving station comprising a trough which is provided with an inlet and an outlet for granular material that is to be purified. A rotatably driven shaft (14) comprising wedging tools (16) thereupon is disposed along the longitudinal axis of the trough. The material is conveyed through the trough between the inlet and the outlet. The side of the trough, on which the tools rise, narrows towards the top and the interior away from the vertical above the central axis of the shaft (14), whereby the section of the circumference, via which pressure is applied to the material during the upward movement of the tools (16), is extended.

Description

- Dissolving station

Description

The invention relates to a dissolving station for granular material, especially for minerals to which soft matter, e.g. mud and/or clay, adheres, lumpy mineral conglo- merates or the like. The station comprises a trough with an inlet and an outlet for the material that is conveyed through the trough between inlet and outlet. Arranged in the longitudinal axis of the trough is a rotatably driven shaft fitted with wedging tools.

EP 0 712 665 Al discloses a washing plant for gravel with adhering matter that can be washed off. The plant has washing tools that enclose a wedge angle with the circumference of the trough, so as to ensure a strong wedging effect on the material.

This results in a high pressure build-up and a strong squeezing, rubbing and dissolving effect on the material to be treated.

The EP 0 712 665 Al does not contain more detailed information on the shape of the trough. The shape of the trough is, in principle, not critical seeing that during operation the trough becomes encrusted, i.e. a lining of adhering material is formed on the trough wall which extends in the circumferential direction of the shaft and between which and the wedging tools a working gap remains. The encrustation of the trough is desirable since this counteracts wear.

The typical shape of a trough that is open at the top and inside which a shaft is arranged can be noted from DE 24 54 443 Al or GB 2081 117 A. The trough has a semicircular bottom and vertical side walls. The shaft lies in the longitudinal axis of the cylinder.

The bottom and walls of a trough of the dissolving station according to the invention can be pre-manufactured, but this is not essential. Also with other trough shapes it can be assumed that generally this inside contour of the trough will occur as a result of the encrustation.

For an effective dissolving it is not sensible to fill the trough to above the height of the shaft. Material located above the shaft is essentially only shovelled around. No significant pressure build-up takes place, seeing that the trough is open at the top and cannot become encrusted here. "Also in the downward movement of the wedging tools the pressure build-up on the material to be treated is not substantial. The material essentially executes a falling movement helped along by the force of gravity. The pressure build-up decisive for the effectiveness of the dissolving takes place during the upward movement of the wedging tools.

The object of the invention is to provide a dissolving station of the type mentioned at the outset with improved dissolving effect.

With the dissolving station by which this object is achieved the trough, on the side where the tools move upwards, narrows towards the top and the inside away fromthe ~ vertical above the central axis of the shaft. This extends the circumferential section via which pressure is applied on the material during the upward movement of the tools.

Between the narrowed part of the trough and the tools a wedge effect occurs, either directly or between the tools, and a lining with which the narrowed part becomes encrusted.

Whereas with conventional troughs the central angle through which an upward movement of the wedging tools takes place with a strong wedging effect amounts to 90°, as a result of the narrowing according to the invention this central angle can be extended by up to 35° above the horizontal. This goes hand-in-hand with a con- siderable improvement in the dissolving effect.

In a preferred embodiment the trough is drawn-in so as to form the narrowed section.

In an alternative preferred embodiment the trough is narrowed by means of an insert.

The two types of narrowing can also be combined. In that case a drawn-in trough comprising a suitable insert is provided.

The insert that narrows the trough can be rigid. An advantage of this variant is that the insert easily becomes encrusted. However, there is a risk of damage when changing over to materials with a larger particle size or when large size impurities unexpectedly occur in the material.

In a preferred embodiment the insert that narrows the trough is, therefore, movable.

The insert may in particular be attached to the trough in an articulated manner.

In a preferred embodiment the insert is elastically cushioned against the trough. This prevents that material to be treated settles between the trough and the insert, which could adversely affect the mobility of the insert.

In a preferred embodiment the insert is spring-mounted against the trough. As spring a compression spring of spring steel can be used. Also a gas spring has proved suitable, the spring characteristics of which should preferably be adjustable.

For adjustable inserts attached in an articulated manner extensive prior art exists for impact mills (see DE 23 00 715 Al, DE 30 18 056 Al, DE 40 37 036 Al, FR 26 72 515 A1,US 40 17035 A, US 4140 284 A, US 45 06 837 A and others). The inserts : are nothing else but impact surfaces. Impact mills have a shaft that is fitted with beating tools. The conveying path of the material to be comminuted extends from the top downwards transversely to the shaft. In contrast thereto, with the appliance according to the invention the material to be treated is conveyed in the longitudinal direction of a shaft fitted with wedging tools. The inserts provided according to the invention serve to build up pressure on the material by way of a wedging effect. The prior art of the impact mills is not relevant here.

In a preferred embodiment the insert has an active surface which is curved in the circumferential direction of the shaft or extends tangentially or polygonally thereto.

In a preferred embodiment the active surface in the direction of rotation of the shaft extends towards the wedging tools, so that the wedge gap narrows. This is especially recommended on the last straight sections of the central angle extended by the insert, over which an upward movement of the wedging tools with strong wedging effect takes place.

In a preferred embodiment the active surface of the insert is structured in a manner that holds the material to be treated. This assists the encrustation of the insert and counteracts wear. The active surface may, in particular, be provided with parallel grooves that extend in the longitudinal direction of the shaft. These grooves preferably have a U-profile.

In a preferred embodiment the insert is provided with at least one inlay of ceramic or hard metal, which reinforces the active surface.

In a preferred embodiment the trough is provided, in the narrowed section, with identical or dissimilar wear sets. To ensure the feeding in of force in the direction of rotation, these wear sets are at the front supported on the trough or insert in a form- locking manner.

In the following the invention will be explained in more detail with reference to the exemplified embodiments illustrated in the drawing. Shown are diagrammatic side views of dissolving stations comprising a trough and a shaft running therein, which is fitted with wedging tools. The view is in the longitudinal direction of the shaft, i.e. in the conveying direction of the material to be treated.

All dissolving stations illustrated in the drawing comprise a trough 10 and vertical side walls 12. In Fig. 1, Fig. 2 and Fig. 5 to Fig. 8 the bottom 10 is semi-cylindrical, in Fig. 3 it is rectangular and in Fig. 4 prismatic.

A shaft 14 is arranged in the cylinder axis of the trough, which shaft 14 is fitted with wedging tools 16. With regard to the attaching of the tools, reference is made to EP 0 712 665 Al and DE 202 18 917.1 Ul.

The dissolving stations serve to free granular mineral material from soft matter adhering thereto. To this end the stations normally operate wet. Water is passed through the trough in counter-current to the material to be treated. The use of water for washing the material is, however, not essential for the invention. There are special cases where dissolving stations operate better dry.

With the dissolving stations illustrated in the drawing several measures have been taken to narrow the gap between the one vertical side wall 12 of the trough and the shaft 14 with the wedging tools 16, which was done at the spot where the tools 16 execute their upward movement. The narrowed section is generally located directly above the central axis of the shaft 14. However, in the one or other case (see Fig. 7 and Fig. 8) it already commences slightly below this.

In order to narrow the gap, with the illustrated exemplified embodiments the trough is provided with inserts. This creates flexibility. It is possible to work with or without an insert, as required. However, it is also possible to draw-in the side wall 12 of the trough to in this way achieve the desired narrowing of the gap.

The trough of the dissolving systems becomes encrusted during operation in a thickness that is indicated by the line 18. On the bottom and on large parts of the trough circumference a lining is formed of the material to be treated, which adheres to the trough. The encrustation is desirable. It counteracts wear.

On the vertical side walls 12 of the trough above the central axis of the shaft 14 normally no significant encrustation can be noted. The material is pushed away upwards. The formation of a lining is prevented by the force of gravity, the friction of the material conveyed through the trough and possibly the flow of water.

It is the object of the invention to extend the circumferential part of the trough that becomes encrusted in the upward rotation direction of the wedging tools 16 provided on the shaft 14, so as to improve the dissolving effect. Fittings can be used for this which take the place of the not naturally formed lining, or which become partly or totally encrusted in the desired manner.

With the exemplified embodiment according to Fig. 1 a wedge-shaped insert 20 is rigidly connected to the vertical side wall 12 of the trough, on which the upwards movement of the shaft 14 with the wedging tools 16 takes place. The base 22 of the wedge is located at the level of the shaft axis. The flat slanted surface (active surface) 26 of the wedge narrows the gap between the trough wall 12 and shaft 14 above the shaft axis. The wedge becomes encrusted over approximately half the length of the active surface 26 and this in the thickness of the lining that forms in the bottom section of the trough.

With the exemplified embodiment according to Fig. 2, with an also rigidly attached wedge the active surface 26 is curved in extension of the trough bottom. The active surface 26 becomes encrusted over the entire length without requiring a special structuring.

With the exemplified embodiment according to Fig. 3 a wedge-shaped insert 20 similar to the one of Fig. 1 is designed as a housing with chambers 28 that are open towards the shaft. The flat partition plates 30 between the chambers 28 essentially extend radially to the shaft 14. This construction assists the encrustation of the insert 20.

With the exemplified embodiment according to Fig. 4 an insert 20 is attached to the trough wall 12 in an articulated manner at the height of the central axis of the shaft.

The articulation axis extends parallel to the shaft 14.

The surface of the insert 20 according to Fig. 4 is stepped once polygonally, so that two flat slanting surfaces (active surfaces) 26 are formed with an essentially tangential inclination towards the shaft 14. Between the insert 20 and the wall 12 of the trough an elastic bolster 34 of rubber or a rubber-like material is arranged. The bolster 34 serves to ensure an elastic cushioning effect. It prevents that material to be treated settles between the insert and trough wall, which could adversely affect the articulation mobility of the insert.

With the exemplified embodiment according to Fig. 5, an insert 20 mounted in an articulated manner is, in addition to the elastic bolster 34, cushioned against the trough wall 12 by a compression spring arranged above the bolster 34. The active surface 26 of the insert 20 is curved co-axially to the shaft 14 in the circumferential direction. At the height of the shaft axis it has a distance from the trough wall 12, which corresponds approximately to the thickness of the lining which forms underneath the insert 20 as a result of encrustation. U-shaped grooves 38 are provided in the active surface 26 which during operation become filled with material.

According to Fig. 6, with an insert the design of which for the rest corresponds to that of Fig. 5, inlays 40 of ceramic or hard metal are provided in the grooves 38, which fill out the grooves 38 completely.

With the exemplified embodiments according to Fig. 7 and Fig. 8, the insert 20 is stepped polygonally twice, so that three slanting surfaces (active surfaces) 26 are formed with an essentially tangential inclination towards the shaft 14. The inserts 20 are attached to the trough wall 12 in an articulated manner underneath the shaft axis and cushioned against the trough wall 12 by an elastic bolster 34 and a gas spring 42 arranged above same. The spring characteristics of the gas spring are adjustable.

In Fig. 8 the slanting active surfaces 26 of the insert 20 are formed by three identical wear sets 44 which are provided with grooves 38. The wear sets 44 are supported in a form-locking manner in the direction of rotation at the front on the lug 46 of the insert 20.

List of reference numerals

Bottom 12 Side wall 14 Shaft 16 Tool. 18 Line

Insert 22 Base 26 Active surface 28 Chamber

Partition plate 32 Articulation axis 34 Bolster 36 Compression spring 38 Groove 40 Inlay 42 Gas spring 44 Wear set 46 Lug * %k *

Claims

I AMENDED CLAIMS [received at the Inernational Office on 28 May 2004 (28.05.04) original claims 1-16 replaced by amended claims 1-16 (2 pages)] New claims l. Dissolving station for granular material, comprising a trough which has an inlet and an outlet for the material and, arranged in the longitudinal axis of the trough, a rotatably driven shaft fitted with tools, wherein the material to be cleaned is conveyed through the trough between inlet and outlet, and wherein the trough, on the side where the tools move upwards, narrows towards the top and the inside away from the vertical above the central axis of the shaft, characterised by wedging tools for building up the pressure on the material by a wedging effect.
2. Dissolving station according to claim 1, characterised in that the trough is drawn in.
3. Dissolving station according to claim 1 or 2, characterised in that the trough is narrowed by an insert.
4. Dissolving station according to claim 3, characterised in that the insert is rigid.
5. Dissolving station according to claim 3, characterised in that the insert is movable.
6. Dissolving station according to claim 5, characterised in that the insert is attached to the trough in an articulated manner.
7. Dissolving station according to claim 5 or 6, characterised in that the insert is elastically cushioned against the trough.
8. Dissolving station according to any one of the claims 5 to 7, characterised in that the insert is spring-mounted against the trough.
9. Dissolving station according to claim 8, characterized in that the insert is a gas spring with adjustable spring characteristics. Amended 20 January 2006
10. Dissolving station according to any one of the claims 3 to 9, characterised in that the insert has an active surface which is curved in the circumferential direction of the shaft or extends substantially tangentially or polygonally thereto.
11. Dissolving station according to claim 10, characterised in that the active surface in the direction of rotation of the shaft extends towards the wedging tools.
12. Dissolving station according to claim 10 or 11, characterised in that the active surface of the insert is structured in a manner that holds the material to be treated.
13. Dissolving station according to claim 12, characterised in that the active surface of the insert is provided with parallel grooves that extend in the longitudinal direction of the shaft.
14. Dissolving station according to claim 13, characterised in that the grooves have a U-profile.
15. Dissolving station according to any one of the claims 10 to 14, characterised in that the insert is provided with at least one inlay of ceramic or hard metal which reinforces the active surface.
16. Dissolving station according to any one of the claims 1 to 15, characterised in that the trough is provided, in the narrowed section, with identical or dissimilar wear sets.
17. Dissolving station according to claim 16, characterised in that the wear sets are at the front supported on the trough or insert in a form-locking manner. * kk Amended 20 January 2006