CA1066231A

CA1066231A - Directionally vibrated slurry separator

Info

Publication number: CA1066231A
Application number: CA276,984A
Authority: CA
Inventors: Shinobu Makino
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1976-05-10
Filing date: 1977-04-26
Publication date: 1979-11-13
Also published as: IN155912B; DE2719596A1; FR2350883A1; AU502437B2; AU2362577A; GB1558433A; ES458619A1; PL197964A1; ZA772714B; NL7703322A; DE2719596B2; FR2350883B1

Abstract

ABSTRACT OF THE DISCLOSURE

A slurry separator has a riffled deck that is inclined transversely of the riffles and an exciter that vibrates the deck along a predetermined line of attack axis. This axis is inclined relative to the deck in a plane that extends longitudinally parallel to the riffles and perpendicular to the deck. The axis has a vertical component and the exciter is capable of accelerating the deck to a maximum vertical acceleration that is greater than the acceleration of gravity. Slurry fed upon the deck adjacent a feed side thereof flows by gravity down the inclined slope, transversely of the riffles, towards a discharge side of the deck. High density solid parti-cles within the slurry tend to settle and these particles are restrained by the riffles from flowing down the in-clined deck, while the remaining slurry, that includes low density solid particles and. a liquid carrier, flows over the riffles. The deck vibrations convey the high density particles generally parallel to the riffles in a series of rabbit-like hops toward an end of the deck where the particles are discharged.

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Description

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BACK~ROUND OF THE INVENTION
Field of the Invention The present invention relates to an improved con-centrating table type of separator that has a riffled deck, with the deck being inclined transversely of the riffles, and a drive mechanism for reciprocating the deck in a direction generally parallel to the riffles. Further-more, this invention pertains to an improved method of separating by stratification high density solid particles .~ .
, 10 from a slurry, that also contains low density solid parti-- cles suspended in a liquid carrier, and divergently con- ;~
veying the high density particles and the remaining slurryn Description of the Prior Art A concentrating table type of materials sepaxating apparatus is shown in United States patent No. 3,075,644 that issued on January 29, 1963 to F. S. Ambrose. The basic elements of the apparatus are a riffled deck and a drive mechanism that imparts a substantially horizontal recipro-cating motion to the deck in a direction parallel to the riffles. The deck slopes downwardly in a direction trans-verse to the riffles from a feed side of the deck to a dis-charge side of the deck.
A mixture of solid particles suspended in a liquid carrier, as a slurry, is fed onto the deck adjacent a cor-ner thereof between a head end and the feed side. Theslurry tends to flow down the inclined deck, transversely ; across the riffles, and carries low density particles there-with from the feed side towards a discharge side. High density particles are restrained by the riffles from flow-ing down the inclined deck, and the horizontal reciproca-' ' '. " ' ' .

ting motion of the deck tends to convey these particles para-llel to the riffles in a direction from the head end of the deck toward a discharge end thereof.
The deck is adjustably supported so that it can be tilted transversely of the riffles about the axis of recip-rocation to either raise or lower the discharge side of the deck. This "side tilt" adjustment provides one way to con-trol the flow of slurry transversely across the deck. In this manner, the transverse velocity of low density parti-cles and liquid carrier across the deck can be increased ordecreased. The deck can also be adjusted to raise or lower the discharge end and thereby control to some extent the -longitudinal flow of solid particles, while limiting the ;
flow of liquid carrier to prevent overflowing from the dis-charge end of the deckO
The drive mechanism, that imparts a horizontal reciprocating motion to the deck, provides the primary longitudinal conveying action for t~e high density solid l particles. The velocity of these particles, traveling : ::
longitudinally of the riffles, is one of the controlling factors that determine the rate of par-ticle flow in that direction and the rate of flow at which slurry can be fed onto the deck. The high density particles must move at a rate sufficient to prevent a build up of such particles upon the deck, or else, the rate of slurry feed to the deck must be limited. Thus, the capacity of the separator is limited by the high densi-ty particle velocity. The horizontal recip-rocating deck motion does not provide a high velocity for the particles traveling longitudinally parallel to the riffles.
A vibratory feeder, having an exciter that ~ -!; ' ", '' '' ", : . ' , ' ' ~ ' . '', ', , :
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vibrates a feeder trough along a predetermined line of at-:~ tack axis, is shown in United States patent ~os. 3,396,294 : that issued on August 5, 1968 to S. Makino, 3,479,5~2 that issued on ~ovember 18, 1969 to S. Makino; and 3,583,553 that 5 issued on June 8, 1971 to Spurlin et al. The axis is in-clined upwardly to the feeder trough in the direction of feed and this axis has a vertical component. The exciter is capable of accelerating the trough, to a maximum vertical acceleration, that is greater than the acceleration of grav-. 10 ity~ United States patent No. 3,904,517 that issued on Sep-tember 9, 1975 to Donald C. Wilson shows a separator with an exciter, that develops vibrations along an upwardly inclined :
axis, but the separator does not have a riffled deck. The principle utiliæed for separation of particles by this sep- ~:
, 15 arator differs from that of the concentrating table type of separator wherein after stratification, there is separation ~ upon a plane at the tops of the riffles by the cross-water ~ ~low.
.: SUMMARY OF THE I~VENTION
According to the present invention there is pro-vided in a separator for removing high density solid parti-cles from a slurry that also contains low density solid par-ticles suspended in a liquid carrier, said separator having ;
an imperforate deck with a support surface to receive the slurry, a plurality of spaced riffles that extend both up-wardly from the deck support surface and longitudinally in parallel relationship with each other, said surface being sloped downwardly from a feed side that receives the slurry to a slurry discharge side whereby the slurry flows trans-versely across said rifles carrying the low density parti-.
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- cles therewith, said riffles having a height sufficient to restrain the high density particles in the interstices form- : ;
ed between riffles, means for resiliently supporting said ~ deck, and an exciter that is coupled to the deck for genera- ~ .
: 5 ting and transmitting vibrations to the deck along a prede-termined line of attack axis as to progressively advance the ~ high density particles along the deck in a direction genera~
:. lly parallel to said riffles, the improvement comprising said .
exciter being aligned in relationship to the deck so that the :.
predetermined line of attack axis is inclined to the deck support surface and has a vertical component, and said ex- :~
:~ citer being capable of accelerating the deck along the line :~
of attack axis to a maximum vertical acceleration that is ~ .
. greater than the acceleration of gravity whereby the high density particles progress generally parallel to said rif-fles by a series of rabbit-like hops induced by the deck vibrations and the slurry on the table is agitated to wash the low density solid particles transversely over the rif-fles. ~ :
According to another aspect of the invention there is provided in a method of separating high density solid par- ~ :
ticles from a slurry that also contains low density solid particles, suspended in a liquid carrier, said method inclu-ding the steps of feeding the slurry at a predetermined rate of flow upon an inclined support surface, subjecting the slu-~ rry upon the support surface to gravitational forces that . .
cause the slurry to flow downwardly along the inclined sup- ~ .
port surface towards a discharge side thereof, restraining :~ the flow of ~igh density solid particles on the support sur- .
: 30 face in the direction of slurry by a series of parallel -3a-~
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rection o~ slurry flow, and progressively advancing the high ~ density solid particles along the support surface by vibra-., 5 tional impulses in a direction generally parallel to the riffles towards a discharge end of the support surface, the improvement comprising directing said vibrational impulses .
along a predetermined line of attack axis that is inclined to the deck support surface and has a vertical component ~, 10 with the vibrational impulses having a maximum vertical acceleration greater than the acceleration of gravity.
BRD3F DESCRIPTION OF T~IE DRAWI~
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Figure 1 is a perspective view of a concentrating table type of separator, embodying the present invention. ~
A discharge trough and a discharge channel are shown ad.ja- :
cent a discharge side of the separator.
Figure 2 is a side elevation view of the separa-tor shown in Figure 1, with the discharge trough and the discharge channel broken away but indicated in phantom .
line.
Figure 3 is a broken end elevation view of the separa-tor shown in Figure lo ~:
Figure 4 is a diagrammatic view of the action that is induced by the d.eck vibration to move a single high density solid particle. ~ .
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to Figure 1, a separator 10 has an imperforate deck 11 with a support surface 12. A headend wall 13 and a feed side wall 14 enclose a portion of the d.eck, while a d.ischarge end 15 and a discharge side 16 of the deck remain open. A series of parallel spaced ` 20 rifles 18 and 19 project upwardly from the d.eck support .'. surface and extend generally perpendicular to the head ~. `
end wall. The riffle patterns are designed in accordance .`
with the characteristics Oe the material being handled.
Usually the riffles are approximately 1/4" to 1" high at ..
the head. end wall and taper d.own to zero before reaching the discharge end. The riffles 19 are spaced about every -:
fourth rifle, and these riffles are higher than the riffles 18 to prevent large high density particles from rolling transversely across the riffles when the inter-stices between riffles are filled with fine high density .' ~ .
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particles. Such fines tend to settle beneath the large ` particles and thereby elevate the large particles to a higher stratum. The shallow riffles 18 tend to spread the . band of particulate material over a wider area to facili-5 tate segregation, while the higher riffles provide pools for the settlement of fine grains. .
The support surface 12 of the deck 11 slopes downwardly from the feed side wall 14 to the discharge side 16, in a d.irection lateral to the riffles 18 and. 19. The angle 20, as shown in Figure 3, that is located between the transverse slope of the deck and the horizontal, ranges ~:
between 4~ to 12, in the d.irection lateral to the riffles. ;~:
The deck top surface is upwardly inclined from the hori-zontal by an angle 21, as shown in Figure 2, ranging :~ 15 between 1/2 to 2, in the direction parallel longitud.i-.~` nally of the riffles, from the head end wall 13 towards the discharge end 15.
A pair of longitudinal frame members 23 and 24, shown in Figures 2 and 3, project d.ownward.ly, perpendicu-lar to the deck 11. A series of transverse frame members 25, 26, 27, 28, 29 and. 30 project laterally outward. from the frame member 23 to support the d.ischarge sid.e portion of the deck, and a series of transverse frame members 31 project laterally outward from the frame member 24 to sup-port the feed side portion of the d0ck. A forward. bracket 32 and. a rear bracket 33 extend. transversely between the longitudinal frame members. Between these brackets, an .:
exciter 34 is resiliently mounted by drive springs 35 and 36, that are arranged. to flex in a direction along a pre-determined. line of attack axis 37. This axis is inclined , ~. . . . . .
. , , at an angle 40 of about 20 degrees to the d.eck support sur-face 12, in a plane that extends longitudinally parallel to the riffles 18 and 19 and perpendicular to the support surface, and the axis has a vertical component. The ex-citer has a housing 38, within which rotatable eccentricweights are located., and these weights are driven through a suitable d.rive by an electric motor 39 that is mounted on the exciter housing. The exciter is capable of genera-ting a maximum vertical acceleration on the deck within a .
range approximately between 1.25 to 2 times the accelera- ~ .:
tion of gravity at 0.4 inch stroke. The exciter operates at 1100 cycles per minute. Such exciters are stand.ard com- .~. :
mercial items, and. a suitable exciter is the "MF-600"
Exciter, manufactured by the MHE Division of FMC Corpo- :
ration, Homer City, Pennsylvania. . --:
. The d.eck 11 is resiliently supported to enable it to vibrate freely. A pair of brackets 41, only one of which is shown in Figure 2, are mounted. to the deck :
adjacent the feed end thereof. These brackets are mounted upon coil compression springs 42 that rest upon ad.justable seats 43. The seats are attached. to bolts 44 that are ~, ; .
.~ threadably ~itted within sleeves 45, and each of these sleeves are mounted to a channel post 46. The posts are ., ,.~, .
mounted. upon a support frame 47 and these posts are 25braced longitudinally by the braces 48. Near the d.eck discharge end. 15, a bracket 50 projects outwardly from .
the longitudinal frame member 23. This bracket rests upon . .
a coil compression spring 51, that is seated upon an ~ .
adjustable seat 52. The seat is attached. to a bolt 53, that is threadably ~itted within a sleeve 54. This sleeve :.

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.~ . is mounted to a channel post 55, that projects upwardly .: from the support frame 47. The post 55 is supported in a direction longitudinally of the deck by a brace 56~ Simi-larly, a bracket 58 projects outwardly from the longitudi- .. .
nal frame membex 24, and this bracket rests upon a coil compression spring 59, that is seated upon an adjustable seat 60. This seat is attached. to a bolt 61, that is threadably fitted within a sleeve, not shown. A channel post 62 projects upward from the support frame 47 to ~up port the sleeve~ not shown. It should be understood that the above described deck mounting merely represents one form ln which the deck could be resiliently supported~ :
It could also be suspended by springs and ca~le- from a ceil;ng. :.
Looking again at Figure lo a f~ed channel 64 is : positioned. or feeding a slurry mixture upon the decX
suppor~ surface 12, at a location adjacent the corner of the head end wall 13 and the feed side wall 14. Additional water is fed upon the deck support surface ~rom spray noz-. ~les in the headers 65 and 66, that are positioned adja-i.. . .
cent the feed side wall 14~ Risers 67 and. 68 supply water to the header 65, and a riser 69 supplies water to the header 66. A discharge trough 70 i5 separate from ~he deck 11, but this trough is positioned ad~acent t~e discharge side 16, to collect low density particles and liquid. car-. rier, overflowing rom the deck. A drain channel 71 extends, from the lowermost portion of the krough, to a . suitable discharge location.

In operation, the separator 10 is particularly suitable for washing and cleaning coal by removing rock, 23~
slate and pyritic sulfur. Such refuse has a higher den-; sity than the coal and is discharged at the discharge end 15, while the coal and water flow over the discharge side 16~ into the discharge trough 70 and the drain channel 71. The separator can also be used for separating various ores, in which case the high density minaral concentrate is discharged from the discharge side. In the following description of the method of operation, reference ; will be made to high or low density particles and it will be understood tha~ such separation can be made for various materials.
A slurry, that includes both high density solid particles and low density solid particles suspended in a liquid carrier, is fed at a predetermined rate of flow, from the slurry feed channel fi4~ onto the deck support sur-face 12. Gravitational forces cause the liquid carrier and the low density phrticles to flow, transversely of the riffles 18 and 19, down the inclined deck, in a direction towards the discharge side 16, while the high density par-ticles settle in the interstices between rifflesO Theriffles restrain the high density particles rom flowing - transversel~ of the riffles, and the vibrational impulses, imparted to the deck ll by the exciter 34, advance the high density particles, along the support surface, -towards the discharge end 15, in a direction generally parallel to the rif1es.
With reference to Figure 4, ~he action of a single high density particle, moving along the deck support surface 12, towards the discharge end 15~ is illustrated.
At the beginning of a vibration cycle, the deck is in the :.

bottom position. The particle is.in contact with the deck support surface, from the lowest poin~ A to approximately the midpoint of the ~ibration stroke, near the neutral deck position. At this point, the particle has ~een accelerated to its maximum velocity and leaves the support surface on a free flight trajectory~ while the support sur-face is decelerating from point B to point C. The particle continues on its trajectory, as the dec~ returns to the bottom position, and the particle rejoins the suppvrt sur-.
faceO at point Al, to complete on vibration cycle~ Itshould be noted ~hat the deck is elevated. in a plane per-pendicular to the transversely inclined support surface, but the particle falls in a vertical plane. Thus~ ~here is a ~light amount of latexal travel for the particle with e~ch vibration cy~leO
~ he above description of single particle action is theoretical and does not ta~e into consideration ~he d.ampening effect of the liquid carrier. Such particle action might be achieved near the deck d.ischarge end 15, but in the area where the slurry flows transversely across the deck support surface 12~ there is considerable agita-tion and. turbulence. Such agitation and turbulence facili-tate stratification, and there is a rapid~ conveying action for high density particles toward the decX dis-charge end.
The feed angle~ or the angle 40 at which the pre-determined line of attack axis 37 is inclined to the deck support surface 12, is preferably about ao degree~ to the deck support surace, in a plane that extends longitudi-nally parallel to the riffles and perpendicular to ~he 3~L ;

support surface. The deck vibrations generated by the exciter 34 have a maximum vertical acceleration within an approximate range of between 1.25 to 2 times the accelera-tion of gravity. This acceleration enables the high density particles to advance in a series of rabbit-like hops along -` the deck, but does not elevate the particles to such an ex-tent that a considerable amount of high density particles jump the riffles 19.
While the high density particles are conveyed towards the deck discharge end 15 for separate disposal, the low density particles and liquid carrier flow, trans-versely over the riffles 18 and 19, towards the deck dis-charge side 16. Upon overflowing this side of the deck, the liquid carrier and low density particles are received in the discharge trough 70, from which they are conveyed ~` through the drain channel 71.
` While the foregoing described embodiment is di-rected to a single deck separator 10, the present invention can also be applied to a dou~le deck separator, as shown in United States patent ~o. 3,075,644 that issued on ~anuary 29, 1963 to F. S. Ambrose. The exciter can be mounted above ~ ;
the decks to be vibrated, and the separator assembly can be suspended by cables and springs from a ceiling. ;
Although the best mode contemplated for carrying out the pre~ent invention has been herein shown and des-cribed, it will be apparent that modification and variation may be made without departing from what is regarded to be ; the subject matter of the invention.
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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a separator for removing high density solid particles from a slurry that also contains low density solid particles suspended in a liquid carrier, said separa-tor having an imperforate deck with a support surface to receive the slurry, a plurality of spaced riffles that ex-tend both upwardly from the deck support surface and longi-tudinally in parallel relationship with each other, said surface being sloped downwardly from a feed side that re-ceives the slurry to a slurry discharge side whereby the slurry flows transversely across said riffles carrying the low density particles therewith, said riffles having a height sufficient to restrain the high density particles in the interstices formed between riffles, means for resiliently supporting said deck, and an exciter that is coupled to the deck for generating and transmitting vibra-tions to the deck along a predetermined line of attack axis as to progressively advance the high density particles along the deck in a direction generally parallel to said riffles, the improvement comprising said exciter being aligned in relationship to the deck so that the predetermined line of attack axis is inclined to the deck support surface and has a vertical component, and said exciter being capable of accelerating the deck along the line of attack axis to a maximum vertical acceleration that is greater than the acceleration of gravity whereby the high density particles progress generally parallel to said riffles by a series of rabbit-like hops induced by the deck vibrations and the slurry on the table is agitated to wash the low density solid particles transversely over the riffles.

2. The improved separator described in claim 1 wherein said exciter is capable of accelerating the deck to a maximum vertical acceleration within a range approximately between 1.25 to 2 times the acceleration of gravity.

3. The improved separator described in claim 1 wherein said exciter is aligned in relationship to the deck so that the predetermined line of attack axis is inclined at an angle of about 20 degrees to the deck support surface in a plane that extends both longitudinally parallel to the riffles and perpendicular to the support surface of the deck.

4. The improved separator described in claim 3 wherein said deck support surface slopes downwardly from the horizontal by an angle ranging between 4° to 12° in the direction of slurry flow and lateral to the riffles.

5. The improved separator described in claim 1 wherein said deck support surface slopes upwardly from the horizontal by an angle ranging from 1/2° to 2° in a longi-tudinal direction parallel to the riffles from a head end of the deck where slurry is received towards a discharge end of the deck where high density particles are discharged.

6. In a method of separating high density solid particles from a slurry that also contains low density solid particles, suspended in a liquid carrier, said method including the steps of feeding the slurry at a predetermined rate of flow upon an inclined support surface, subjecting the slurry upon the support surface to gravitational forces that cause the slurry to flow downwardly along the inclined support surface towards a discharge side thereof, restraining the flow of high density solid particles on the support surface in the direction of slurry by a series of parallel spaced riffles that project upwardly from the support surface and that longitudinally extend trans-versely of the direction of slurry flow, and progressively advancing the high density solid particles along the sup-port surface by vibrational impulses in a direction generally parallel to the riffles towards a discharge end of the support surface, the improvement comprising direc-ting said vibrational impulses along a predetermined line of attack axis that is inclined to the deck support sur-face and has a vertical component with the vibrational impulses having a maximum vertical acceleration greater than the acceleration of gravity.

7. The improved method described in claim 5 wherein said predetermined line of attack axis is inclined at an angle of about 20° to the support surface in a plane that extends both longitudinally parallel to the riffles and perpendicular to the support surface.

8. The improved method described in claim 6 wherein the vibrational impulses have a maximum vertical acceleration within an approximate range of between 1.25 to 2 times the acceleration of gravity.