CA1098866A - Multi column sequential batch settling rate separator for hydraulically conveyable solids - Google Patents

Abstract

Abstract The specification describes a method for the hydraulic conveyance of solids such as coal in a transport medium in the case of which the raw mate-rial to be conveyed is classified into several fractions before passing into the conveying plant.
The raw material is only subjected to sorting into fractions with respect to the grain fractions which predominantly lead to clogging after classification and before hydraulic conveyance.

Description

The invention relates to a method for the hydraulic conveyance of solids, pxeferably coal, in a transport medium in the case of wnich the raw material to be con-veyed is classified before being placed in the hydraulic conveying plant in~o several fractions, and to an a~paratus ~or carrying out the method.
The hydromechanical mining of coal and the transport of the raw coal to be conveyed over extensive distances both horizontally and also vertically has been accepted practice for a number of years. In this respect diffi-culties arise because the raw coal to be conveyed can only be transported hydraulically up to a certain grain size. In order to avoid excessively high pressures the practice was taken even in the early days of classifying the raw coal to be conveyed while still underground so as ~o produce a transportable grain fraction and a non-trans-portable grain fraction. While the fine grain fraction can be transported over long distances even in the ver-tical direction, ~he coarse grain material is separated and in the previously conventional mannex is hauled in wagons to above ground or made use of in some oth~r manner under~round or comminuted. Furthermore it has b~en found that in the case of the hydraulic conveyance of `~
solids with different grain sizes and different densities ~:
the different resistances of tne solid particles in the flowing liquid glve rise to substantial di~ferences in speed of the so:lid particles. This is disadvantayeous as regards the hydraulic conveyance in as far as the different transport speeds in the shaft duct lead to undesired con-centrations of materials and cloyging~ Furthermore it hasbeen found that for such a heterogeneous mixture a nigher ..;, 6~

transport speed i5 necessary. ~ince com~licated classifi-cation and sorting underground gives rise to excessive costs the disadvantages tied to the above me~tioned effect have so far been put up with. Attempts have only been made to avoid tne effect by dividing out, as already mentioned, the coarse grain siæes and transporting tnem separately in a transport wagon.
In view of the fact that it is more particularly the coarse fractions or grain sizes of the heavier components of the raw conveyed coal that lead to the trouble with clogging one aim of the invention is that of providing a method which makes pGssible an increase in the volume con-c~ntration at a lower conveyance speed and simultaneously avoids concentrations of material and clogging. At the same time an apparatus is to be created with which the method in accordance with the invention can be put into practice.
In order to a~tain these and other aims the invention provides that the raw material for conveyance is only fractionally subjected to sorting with respect to the grain fractions which predominantly lead to clogging after classi- -~
fication and before hydraulic conveying. The method in accordance with the invention is accordingly intended to hold back all parts of the raw material for conveyance, whose settling velocity is greater than the settling velo-city of the maximum sized pure material to be conveyed.This appli~s for a raw coal to ~e conveyed for e~ample, hile in the case of an ore conveyance must be precisely ~ the reverse. Tne separation of heavy matter witll a size a'Dove 10 mm furthermore offers the advantage that in the treatment of the material above ground the material with a grain size above 10 mm only comprises pure coal and ~9~

all material above 10 mm can be further processed in the fine grain processing system without changing the washing system. ~he heavy fractions separated underground can therefore be hauled out of the mine outside normal con-veying time and, as a further possibility, however, can ~e used as pac~ing.
The desired sorting effect is achieved in a particu-larly accurate and satisfactory manner if, in accordance with the proposal of the invention, the classified material ~ is subdivided intodefined quantities and is premi~ed with the separating medium before it is abruptly, that is to say speedily charged into a shaft filled with separating medium. In the case of sorting the invention takes ad-vantage of the physically occasioned difference in the settling rate of fractions of materials of the same si~e ~ut which have a considerable difference in density. Thiseffect is particularly well brought into play when the material to be charged has been classfied as strictly as possible beforehand. The individual fractions are then subdivided by suita~le means into portions of the same size and then even at this stage premixed with the separating medium in order, even at the ~eginning of the separatiny operation to have tile same starting state for the individual grains and in order to avoid movemen~s of the separating medium which would impede the separating operation. The material whicll was classified into the individual fractions in the individually defined quantities is then removed underwater in the appropriate shafts, such removal heing carried out suddenly, that is to say at high speed in order to ensure that approximately all grains sink downwards simultaneously in the separating medium and t-hat the desired separation from the ~ixture does in fact occur here.
In accordance with the invention separate shafts are provided for the individual fractions and they have a length S corresponding to the grain size. The shortest shaft is provided for ~he smallsst parts and the longest shaft is provided for the largest parts. This makes it possible to ensure that the residence times of tne individual materials to be separated in the shats placed alongside each other are of equal duration.
The method in accordance with the invention can be carried out with a separating device, which consists of allotting means, a housing filled with water and removal means and in the case of which, in accordance with the present invention, a drive shaft is provided with several allotting means, which are arranged with an offset in relation to each other on the drive shaft and in the case of which the drive shaft is provided with means for pro-ducing a desired timing relationship between it and the ~0 cylinders. Ilith such a separating device it is possible to obtain simultaneously all fractions which occur within classi~ication, and they can be sorted in the device and automatically se~arated from each other. The use of the drive shaft and the cylinders, which serve for actuatins the slide and the flaps, as timing means makes possible a simple and mutually timed control of the allotting means and the separating means.
The number of grain fractions produced as part of the classification is determined in accordance with the type : 30 of the material supplied. Generally tile material supplied will have to be classified into seven to eight grain sizes, one grain fra~tion ~eing tne tailinys, ~ilich yen~rally cannot be nydraulically transported without special trea~-m~nt. AccQrdingly in accordance with the invention a num-ber of allotting devices is provided which corresponds to the number o~ desired grain fractions . . Generally a sepa-rating device in accordance with the invention will accord-inyly have six or seven allotting devices, which are of the same basic structure. This has the purpose and simultane-ously offers the ~dvantage of making it possibla to sort immediately and simultaneously the whole of the raw ~
material to be conveyed in all grain sizes, with the ex- ~ ~r ception o~ the tàilings.
The allotting device is the intermediate member be-tween classification and separating shafts. It can in ~;
accorda~ce with the invention store material coming fromthe sieve. In this respect it is possible, in accordance with the invention , for the allotting device to have several, preferably four chambers, which have the same size of opening and the same filling volume. The identical con-struction of the chambers of the allotting device is neces-sary, since timing can only be caused to function satisfact-orily if the quantities passed into the separating shaft, respectively have the same grain size and the same volume.
Furthermore they should as far as possible all be passed simultaneously into the separating medium, which fills the sha~t.
In order to avo~d early emptying of t~e chambers in the case of the separating device of the invention the chambers of tne allotting device are surrounded by a cas-ing, which closes simultaneously at least the opening ofof two cham~ers. Accordingly it is possible to fill a 36~

cnamber simultane~usly with the new material, while the second chamber, which has become filled at the same point in time in part with water already, can be emptiea by sudd~n or high speed opening of the slide.
Production of movement in the water- surface and in the water column can under some conditions lead to impair-ment of the separating result. For this reason the material is to be mixed with the separating medium even before it is fed into the separating shaft. Such a mixing operation of the material with the separatiny medium is achieved in accordance with the invention ~y ensuring that the allotting device ex~ends partly into the housing filled ~7ith the separating medium. In this manner the separating medium can pass through slots or other openings, which a~e provided in the casing or the slide, into the respective lower chamber and wet the material located in it. Satis-factory sorting in accordance with the individual grain fractions is ensured in accordance with the invention if, as proposed, in the intexior of the housing a number, corresponding to the r.umber of the allotting devices of shafts is provided. This makes it possible to ensure that each individual grain fraction can be separated up, without any influence due to external factors, in accordance with the density.
Turbulence in the sllafts filled with the separating medi~n is avoided in accordance wtih the invention by giv-ing the shafts a square cross-section.
The separation of tlle components, passed at different points in time ~o the lower end of the shafts, of the in-dividual components is made simple in accordance wi~ll the invention if, as proposed, at the lower end or the shafts pivotall~ mounted grates are provided ~nd on the housing a counter-member is provided which is pivoted. The two pivotally mounted grates and the respective counter member which is pivotally mounted then perform respectively opposite movements so that firstly the neavier parts and then after changing over the pivotally mounted grates and the counter-member the lighter fractions can b2 passed in-to the preceding compartm2nts at the lower end of the housing.
A synchronous switching over of the pivotally mounted grates and the counter-member is ensured, in accordan~e with the invention, by associating one and the same cy-linder with a l~ver syst~m with the pivotally mounted grates and the counter-member. Owing to this simple engi-neering construction~it is possible to ensure that the pivotally mounted grates and the counter-member respectively perform the necessary opposite movelnent.
The mov~men~s, in~luencing the d gree of success of séparation, of the water column are avoided to a very sub-stantial extent since the pivoting grates and also thecounter-member have openings on the surac~s. As a result the resistance, which the medium has to meet on the move-ment of the pivoting counter-members is kept as small as possible. Since the pivoting members are at an angle to the vertical in every position the sorted material can, without falling through, move over the openings into the pivoting counter-members.
The material provided sorted up into heavy and lighter fractions is firstly deposit~d on the bottom of the housing and from this position supplied to the coal collecti~g space.
For transport use is made, in accordanc2 with the 6~
invention, of at least two conveyiny screws arranged in t~e bottom of the housing. The use of conveying screws mak~s it possible to feed in the material, whicA is then supplied to the hydraulic conveying system, in a cor,dition which is alxeady mixed to an extremely far reaching extent as r~gards grain size. For tne heavier and respectively less valuable components it is in this raspect also possible to use a different transport device, since in this respect mixing is no long r absolu~ely necessaxy.
The grain size distribution changes in accordance with the hardness of the cQal mined. It can therefore be appro-priate to change the grain rang~s of the fractions suitably and/or to reduc~ or increase the number of fractions. Accord-ingly there is the proposal in accordance with the invention to adapt the number and l~ngth of the shafts to accommodate these variations.
The cylinders, which actuate on the one hand the slide ;~
and on the o~her hand the pivoting grates and respectively the pivoting counter-member are connected constructionally with the drive shaft. In accordance with the invention cams arranged to slide on the drive shaft are used as con-trol members for tlle cylinders~ As a result the advanta-geous robust construction is adhered to for the underground arrangement. Furthermore on changes being made in tl-e com~
position of the material supplied or other operational con-ditions the necessary times can be changed without any ex-tensive difficulties by changing the cam discs and the seat of the individual allotting devices.
It is particularly advantageous that o~ing to the cutt-ing out of the dense fraction above 10 mm concentrations of ~9~

material an~ accoraingly clogging is prevented. In all the ~ -hîgher volumetric concentration aimed at is achieved, ~Yhich can be conveyed with a lower conveying speed. Fur~hermore the separating device is generally sturdy and simple in structure and accordin~ly it is adapted to the special con-ditions in mining underground. T1e separating device can be erected and operat~d in the vicinity of dead-end sha-fts or shafts near the surface or in any other spaces suitable for such purposes without any extensive investments. Such successful op~ration was therefore certainly not to have been expected by those skilled in the art.
The manner of operation of the s~parating device and o,her features of the present invention will be described in detail ~Jith reference to the following figures of the accompanying drawings.
Figure 1 shows a section through the separating device~
Figure 2 shows a simplified side view.
Figure 3 shows a diagrammatic sketch of th_ timing or control unit.
Figure 4 shows a timing diagr~n.
The separating device now to be described is intended for separating coal and heavy fractions.
In Figure 1 a housing 1 encloses the main part, com-pletely filled with water, of tne separating device. In the interior 1 there is the shaft 2, shown in secti~n, which in accordance with one form of the invention is preferably of square cross-section.
A~ove ~he housing 1 there is tle supply trough conveyer 13, via which ~le raw material to be conveyed, subdivided after classification into the individual fractions, is _ g _ ~L~9~86G

supplied to the individual allotting devices 3. The inner part 33 rotating a~out the drive shaft 4, of ths allotting device 3 comprises four evenly arranged and identically constructed chambers 6, 7, 8 and 9, which move below the inlet hopper 10 towards the slide 11. ~e drive shaft 4 is connected with the slide 11 for timed movement and the cylinder 12 serves for opening and closing the slide 11.
The bottom 26 of the housing 1 is subdivided into two component spaces, in which the two conveying screws 27 and 28 are to be found. The setting of the housing 1 at an angle 29 ensures that th~ material conveyed is reliabl~
passed into the vicinity of the conveying screws 27 and 28 respectively. Above these parts, ~lat is to say on the center wall 30 of the housing the pivoting counter-me~ber 24 is a~tached. Furthermore at the lo~er end 22 of the shaft 2 on the shaft wall 31 the pivoting grates 23 are fixed so as to allow movement. T~e inner part 33 and the openings 21 of ~le chambers are surrounded by the casing 5 of the allottin~ device 3.
Tlle manner of operatiDn o the separating device is as follows. The classified raw material to be coIIveyed with a predetermined grain size range arrives via the trough conveyer 13 in the chamber 6 just due to be filled with it. Owing to the slow rotation of the rotor this operation las~s a certain period of time so that the cham-ber 6 can be filled with the material to be conveyed~ On further rota~ion the chamber 6 will then reach the position at ~hich in ~igure 1 the chamber 8 is located, which on bein~ turned so as to~move beneath the level 34 of the water, has already partly filled with water. The operation of the cylinder 12 is controlled by the drive shaft 4 so ~9~1~6~

tha~ it operates to move the slide 11 to an open position at a predtermined instant so that the contents of the chamber 8 and 6 respectively can be ernptied suddenly into tne shaft 2 which is filled with water. In this shaft 2 there is, owing to the different settling rates of the heterogeneous material the desired separating or sorting operation. The particles ~hicn has the highest specific gravity are the first to reach tlle lower end 22 of the sha~t ~ and in accordance witn the position, represented lQ in figure 1, of the pivoting grate 23 and the pivoted coun~er-member 24, are passed into the space around the screw 27, which in the exampla shown is used for the heavy fraction. The specifically light material, that is to say th~ coal, reaches the vicinity of the lower end 22 of the shaft 2 only later. Then the pivoting grates 23 ar~
pivoted in the direction of arrow into the position shown in dots, while the pivoting counter-member 24 performs a mo~ement in tne`opposite direc~ionO This feature ensures tnat the material to be conveyed ~coal) now arriving is passed to the conveying screw 28, which is used for coal.
The actuation of the pivoting grates 23 and of the pivot-ing count~r-mer,~er 24 is insured by the cylind~r 25 which, as remains to be explained, is operated or tim~d via the drive shaft. The cylinder ~5 is associated with a lever system 32 which makes it possible to operate simultaneously the pivoting grates 23 and the pivoting counter-member 24 in a mutually opposite direction. The pivoting grates and respectively the pivoting counter-member have holes or similar openings 50 that tne pivoting mer.~rs 23 and 24 offer the least possible resistance to the water. Tnis particular feature of the pivoting members 23 and 24 is 6~;

no~ repr~sented in the drawing.
Figure Z shows the separating device as a w~ole in a simplified elevation view, in which the three-dimensional arrangement of the individual shafts 2 with their dif-ferent lengths and the pivoting grates 23, located res-pectively at the lower end 22 of the shaft 2, and of the pivoting counter-m~mber 24 will be seen togetner with fur-ther specific eatures. Above the allotting device 3, which consists of sevexal segmen~s arranged on the drive sihaft 4 the supply conveyer troughs 13 are arrang~d via which tne material to be conveyed, classified as inte~ded, is fed. I~ the example shown in all six fractions are supplied via the conveyer troughs 13 to t'ne separating d~vice, which accordingly consists of six or respectively five allotting devices. Tests have shown that it is sufficient to divide the material which has a grain size above lO mm into ~he following fractions: 10-20, 20-30, 40-50 and 50-60 mm. The material above 60 mm in grain size is passed over the classifying device and if required further processed and then fed into the classifying device again. The correspondingly sorted material is,after sorting w~th the help of the conveying screw 27 and respectively, the collveying screw 28 following it, conveyed off and placed in the coal storage container.
At ~le end of the drive shaft 4 there are the control slides 14 associated with the individual removing segments, that is to say the slide ll, the pivoting grates 23 and the pivoting counter-member 24. As components for timing it i5 possi~le to use conventional ~lements, Furthermore t'ne arrangement in fisure 2 does not show the segments, g36~i associated ~ith the individual shafts 2, of the allotting device 3, which are indicated in figure l and denoted with ~e~erence numerals 6-9. The parts, mounted on the shared drive shaft 4, of the allotting device are arranged res-pectively witll an offset of 18 so that the removal of tilesolids for each individual allotting device occurs at dif-ferent successiv2 points in time. Figure 3 shows the principle of control with reference to part timing systems.
In the top of f-i3ure 3 of th~ timing unit 14 the three cams 1~, 17 and 19 which belong together and are mounted adjacent to each o~her on t~e drive shaft 4, a~e shown, ~hicll are responsible for actuating the two cylinders 12 ans 25. The four projections 16 of the cam 15 actuate during a full revolution ~he cylinder 1~ four times for a duration corresponding to the angle alpha. The pro jections 18 of the cam 17 and the projections 20 of the cam 19 control the cylinder 25 in such a ~anner tllat after a time, whicll on the cam 17 corresponds to the angle delta, the cylinder 25 is switched over and after a time which on th2 cam 19 corresponds to the angle Psi, is moved back into the initial position again. The time for the timing or control operation itselE is the same for the two cams and corresponds to the angle beta.
The bottom of figure 3 shows the same operations for the next cams 15, 17 and 19, which are provided for the cylinders 1~ and 25 of the next allotting device 3 and respectivel,v the next shaft 2. All cams have the same shape as shown in the top part of figure 3. They are only off-set by t~ angle Delta on the common ~rive snaft 4. This angular offset is also provided between the following control or timin~ units 14 of the remaining parts of the separating device.

~ igure A SilOWS a control or timing ~iagram, ~hicn in-dicates ~e timing of the system indicated in figure 3.
This timiny diagram will serve to show that the tim-ing operations for the cylinders 12 and 25 and accordingly the movements of the pivoting grates 23 and respectively of the pivoting counter-member 24, which in fact all occur underwaler, are listributed over the whole period of a complete revolution of ~le allottiny device 3 so tilat only a slight disturbance can be imparted to the comparatively 10 large quantit~ of water in the main part of the separating ~ !
d~vice. This disturbance is furthermore limited since the shape of the shaft 2 is square in cross-section.
In accordance with the ernbodi~ent shown tne raw coal to be conveyed is first classified for a ~rainsize of below G0 r~m. The material larger than 60 rnm in size is drawn off via the device shown. Its further tr~atTnent does not forrll part of th~ subject matter o the present invention.
The material below 60 mm in size is divided up as follows -amongst the individual supply conveyer trougns.
13 All rnaterial below 10 mm including the entrained water 13' Grain size 10-20 mm 13'' Grain size 20-30 mm ; 13' " Grain size 30-40 mTn 13'''' Grain size 40-50 mm 13''''' Grain size 5C-60 mm

Claims (11)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A separating device for sorting particulate material such as coal or the like to obtain hydraulically transportable particulate material comprising, (a) a housing having an upper end, a lower end and a plurality of sorting chambers extending therebetween, each chamber containing a body of separating medium, (b) distributor means at the upper end of each chamber, said distributor means being adapted to receive pre-separated fractions of a particulate material and to form, in each fraction, a batch of a predetermined quantity, said distributor means being operable to release each batch into an associated sorting chamber of said housing to permit the batch to fall through the separating medium contained therein, (c) first and second collecting means at the lower end of each of said housings for receiving first and second sub-fractions of said particulate material, (d) sorting means mounted in each chamber for move-ment between a first position to direct particulate material to said first collecting means and a second position to direct particulate material to said second collecting means as it falls through said separating medium, (e) actuator means operable to selectively position said sorter means in said first or second position so as to selectively direct said first sub-fraction to said first collecting means and said second sub-fraction to said second collecting means, thereby to sort said particulate material into first and second sub-fractions of different densities.

2. A separating device as claimed in Claim 1 wherein said distributor means comprises a longitudinally elongated rotor having a plurality of batch forming compart-ments at intervals along the length thereof, said rotor being rotatable between a first position in which said batch com-partments may be charged and a second position from which each batch compartment may be discharged into its associated sorting chamber.

3. A separating device as claimed in Claim 2 wherein the number of batch compartments provided along the length of the rotor is equal to the number of fractions into which the particulate material is pre-separated.

4. A separating device as claimed in Claim 3 wherein said shaft is formed with a plurality of circumfer-entially spaced batch compartments at said spaced intervals, each compartment having the same volume.

5. A separating device as claimed in Claim 4 including means closing at least two of said circumferentially spaced batch compartments in all positions of said rotor.

6. A separating device as claimed in Claim 5 wherein said rotor projects into said housing to a level below the level of said separating medium whereby each batch of particulate material may be at least partially submerged in said separating medium before it is discharged into its associated sorting chamber.

7. A separating device as claimed in Claim 1 wherein one sorting chamber is provided for each fraction.

8. A separating device as claimed in Claim 1 wherein said sorting chambers have a square cross-section.

9. A separating device as claimed in Claim 1 wherein said sorting means comprises grate means pivotally mounted in the lower end of each chamber movable between said first and second positions.

10. A separating device as claimed in Claim 9 wherein said grate means is formed with passages opening therethrough to permit the passage of separating medium therethrough while presenting passage of the particulate material therethrough.

11. A separating device as claimed in Claim 1?
wherein said first and second collector means each comprise a conveyor screw arranged to receive said first and second sub-fractions for conveying said first and second sub-fractions out of said housing.