BE525251A - - Google Patents

Description

       

   <Desc / Clms Page number 1>
 
 EMI1.1
 



  THE DORR COMPANY, residing in STAMEORD (EoUaAo) WET CLASSIFICATION.



   The invention relates to a hydro-grader or hydraulic or wet grading apparatus for the treatment of pulp or sludge containing a packed with fine to coarse particles, such as for example metallurgical pulps or pulps of wet crushed ore, in order to to operate the separation or sorting of the mixture of particles into a coarse particle fraction and a fine particle fraction, which will be called coarse fraction and fine fraction, or the higher size and the lower size, or overflow and current fund or deposit.



  The coarse fraction then contains substantially all of the particle sizes greater than an intermediate size or size, while the fine fraction contains substantially all of those smaller than the intermediate size or size.



   The hydraulic separation in question takes place in a classification basin in which the pulp is brought, while the coarse fraction is extracted from the bottom of the basin and the fine fraction overflows above a dam. In order to promote and control the separation, the mixture of particles of various sizes, as it passes through the basin, can be kept in motion by subjecting it either to the action of a controlled mechanical agitation or to the action of an auxiliary stream of water, known as hydraulic agitation, rising in the basin at a controlled rate. However, in the present invention, it will be envisaged that the mixture will be subjected to the combined effects of mechanical action and of hydraulic action, with the desired result that the desired coarse fraction, exceeding a certain sorting caliber,

   will accumulate on the bottom of the basin and be removed from it, while a corresponding fraction of fines, together with the water which carries it, will overflow from the basin, which provides excellent means of

 <Desc / Clms Page number 2>

 control of the separation, as will result from the following discussion.



   One of the basic problems with such a grading or wet separation is that it should be as clear as possible between the upper size and the lower size; The aim is therefore to carry out the classification treatment in such a way or by means of a type of apparatus such that each of the two fractions is obtained as far as possible free of stray particles of the other fraction.



   Another fundamental problem of such a treatment or wet grading apparatus consists in the provision of means of control with the aid of which the point of separation or fractionation between the two groups of sizes, namely the upper size and the size. lower, can be quickly set and fine-tuned. Thus, for example, if the feed is a stream containing particles ranging for example from 28 to 200 mesh (thus passing through the Tyler system sieve of 28 and 200 mesh per linear inch respectively), it should be possible to perform a clean separation at, for example, 100 mesh, but it should still be possible to move the separation rapidly to, for example, 48 mesh.

   This requires the provision of simple and efficient means for controlling or varying the separation point, producing both fractions clean, that is to say with a minimum of particles of undesirable size in these fractions. The importance of producing a clean coarse fraction is evident, for example, when the classification apparatus operates in a closed circuit with a grinder mill, the latter receiving the coarse particles for regrinding, in which case the presence of a large proportion of dispersion fines or gauges would increase the load circulating through the mill and consequently reduce its efficiency, as well as that of the circuit as a whole.



   In addition, account must be taken of the general problem that such an apparatus must be capable of efficiently handling feed slurry containing a relatively wide range of particles of different sizes, i.e. from relatively large particles. fine to relatively coarse particles.



   In the operation of such a treatment and grading apparatus, account must also be taken of the degree of dilution of the feed pulp, since it is desirable to produce a separation or fractionation which remains substantially. stable, despite possible variations in the degree of dilution of the diet; on the other hand, it may be desirable to remove the overflow of fines to as high a density as possible, a difficulty residing in that a high flow rate of agitating water may defeat the goal of achieving a desired degree of stirring. density of the overflow fraction.



   The present invention provides improvements over the wet grading machine which utilizes the simultaneous or combined effect of mechanical and hydraulic grading actions according to US Patent Weber No. 2,320,588; this machine produces a clean separation which is controllable in a simple and efficient manner, and can operate with minimal hydraulic actuation or agitation water, and is capable of absorbing appreciable changes in pulp dilution feed, substantially without affecting the separation itself, although capable of producing the overflow or smaller size fraction at a relatively high density, and it can process feed pulp containing a wide range of particles of various dimensions,

   ranging from fine to coarse particles.



   A particular object of the present invention is to establish a machine having at least the operating characteristics and the capacities.

 <Desc / Clms Page number 3>

 pacities and qualities of the machine according to the aforesaid patent, while being of simpler construction, lower weight, more economical to manufacture and easier to maintain, monitor and repair. The significance of these objects will emerge more clearly from the summary description of the machine according to this patent which will be given below.In this machine, the pulp is brought into a shallow basin, the bottom of which is formed by a horizontal circular false bottom formed by a plate perforated which is commonly referred to as the constriction or contraction plate.



   A hydraulic supply chamber is contiguous with the underside of this plate and water is continuously supplied into this chamber, so that the auxiliary water continuously rises into the basin through this plate, with a controllable flow rate, of way to help keep particles moving in the pond. In addition, this hydraulic chamber, including its perforated plate, is mounted in an oscillatory movement around a vertical axis by means of a hollow vertical column rising from the center of said plate and suspended from it. a support structure mounted above the basin, which carries the motor mechanism for imparting oscillatory movement to said chamber and said plate, through said column.

   The slurry or pulp is fed into a central feed well which surrounds the column and, under normal operating conditions, the pulp in the basin is subjected to the combined effects of the oscillating movement of the perforated plate and the associated hydraulic chamber, and agitation water rising through the plate. This results in a uniform distribution of the stirring water over the entire bottom of the pond, not only because the water is introduced through the large number of perforations in the plate, but also because these perforations oscillate constantly as a result of the movement of the plate.



   The classification basin is further delimited by a cylindrical wall, the upper edge of which constitutes an overflow or overflow dam for discharging the fraction of fines from the pulp. This cylindrical wall of the basin is concentric with the perforated plate, although it has a slightly smaller diameter, so that it is somewhat set back from the periphery of the plate, said wall also lying at some distance above the marginal area of the plate.



  This can therefore oscillate under the stationary cylindrical wall, the spacing between this wall and the plate constituting an annular passage for the sands or solid matter, leading outwards from the bottom of the basin, so as to allow the migration of the coarse pulp outward and its removal from the bassoon. It is important to note that along the periphery of the perforated plate, there is provided a submerged sand discharge dam, above which the sands or the particles of the coarse fraction can flow to fall into a receiving chamber. or collector that surrounds the perforated plate. This barrier rises to a level which is at least a little higher than the passage of.

   sand, so that an annular sealing column formed by the sand migrating between said passage and this dam is maintained.



   The annular space between the perforated plate and the collecting chamber which surrounds it is covered and closed by an upper part of the collecting chamber, which part in fact supports the cylindrical wall of the basin, being rigidly connected to it. this.



   A mass or column of clear water, maintained in the sand collecting chamber and determined by an overflow dam of adjustable height, balances the column of pulp or particles moving in the basin, this equilibrium constituting a condition of hydraulic equilibrium of the machine, which makes it possible to quickly adjust the point of separation of the pulp, in particular by adjusting the height of the clear water overflow.

 <Desc / Clms Page number 4>

 



   This means that when a pulp of a certain degree of dilution is brought into the center of the grading basin, and stirring water is brought through the central hollow column into the chamber of feed located under the perforated plate, while the oscillating structure is kept in continuous motion, stratification takes place in the basin according to the dimensions of the moving particles, the largest particles descending to the bottom and the smaller and smaller particles being placed in corresponding layers succeeding each other from the bottom upwards from the bottom of the basin. Once the working hydraulic equilibrium is reached, this basin produces a continuous overflow of particles of the desired lower caliber ., while the particles of the desired upper caliber accumulate in a bottom zone,

   where, however, they remain sufficiently in motion, partly due to the movement of the perforated plate and partly due to the hydraulic effect of the stirring water, so that they move radially outward in all directions, to cross the sand discharge passage and pass over the submerged sand discharge dam, which surrounds this passage, and thereby access the sands collection chamber, from where they can be removed from a body of water clear, for example using any suitable usual lifting means.

   In short, the sand discharge dam creates a sealing plug in service, formed by the annular accumulation of migrating sand from the pulp column in the basin to the mass of clear water in the sand collecting chamber. , which surrounds it
The exact sorting caliber at which the separation must be carried out depends on the equilibrium condition at which the adjustment has been made, in particular the adjustment height of the clear water overflow dam from the sand collecting chamber;

   that is, the greater the height of this clear water overflow, the greater must be the average specific weight of the pulp column in the basin to satisfy this balance, and the greater will be the size at the separation point o In other words, by increasing the height of the clear water overflow, the separation point will be shifted in the direction of reducing the fraction of upper caliber and a corresponding increase in the volume of the lower size fraction, which means that a part of the particles of the higher size fraction, at the lower limit, of the size range of that fraction, will pass into the size fraction lower under the effect of an increase in the height of the clear water overflow.

   Similarly, when the height of the clear water overflow is decreased, the effect on the separation point will be felt in the other direction. In addition, another adjustment factor is available for varying the separation point, which is constituted by the variation of the flow rate or the pressure of the stirring water supplied under the perforated plate, and therefore the height of the clear water overflow and the agitation water adjustment can be used together or in combination to effect the separation adjustment.
This patented machine gives very satisfactory results and is, in fact, unique from the point of view of the particular service results and adjustment characteristics, as specified above.

   due to the combined action of horizontal mechanical movement and hydraulic action, said known machine is capable of effectively and efficiently processing feed slurry containing a wide range of particle sizes, including range from relatively very fine particles to relatively very large particles; but the inertia of the oscillating masses which are to be accelerated and slowed down is considerable and, therefore, tends to impose a practical limit on the diameter of the structure oscillating, while the perforated plate is also a relatively expensive member and the replacement of which

 <Desc / Clms Page number 5>

 ment requires disassembly of the machine.

   A change of this plate may however sometimes be necessary or desirable, either because of its wear or deterioration, or because it may be desirable to adopt a different arrangement of the holes or perforations in the plate.



   The mass of stirring water in the oscillating structure, under the perforated plate, represents part of the oscillating mass and aggravates the problem of inertia.
Therefore, one of the specific objects of the present invention is to provide a machine which, while having at least the operating characteristics and the advantages of the machine described briefly above, is of better construction. simple and more economical, and allows a sensitive use of oscillating or moving masses and therefore simplifies the problem of inertia, and which provides means for distributing the agitation water , which will avoid the above drawbacks of the perforated plate,

  but which can nevertheless be carried out in such a way as to produce the desired conditions for classifying the particles in motion in the classification basin.



   The invention is based on the principle and the discovery that the introduction of the stirring water in the form of jets, instead of being carried out in the form of oscillating jets directed upwards from the bottom, can be achieved by the provision of stationary jets directed towards the bottom, obtaining practically equivalent results from the point of view of the uniformity of the water distribution From the construction point of view, the invention provides for the arrangement stationary distribution elements which are arranged at the bottom or in the bottom zone of the basin and which comprise means for producing jets arranged and distributed so as to produce, in the bottom fone of the basin, jets inclined at an angle suitable for a solid back and forth motion background;

   the jets are provided in such number, with such dimensions and an arrangement such that the desired state of classification of the moving particles in the basin can be suitably maintained, even with a proportionally minimum consumption of agitation water, the setting of the separation point being comparable to that described above, both from the point of view of efficiency and from the point of view of sharpness
This principle or this discovery can be regarded as residing in the use of the effect of mobilizing solid particles produced by the horizontal back and forth movement of the basin itself in combination with stationary jets directed obliquely towards the sea. low, to establish a stirring water distribution producing the mobilization of solid particles,

   whereby the agitation water rises in fact uniformly from the entire extent of the active surface of the foundation. A jet distributor system is provided, which is supported and fed from above, easily lending itself to the operation. inspection, replacement and maintenance, without requiring any disassembly of the machine itself.



   In summary, the invention comprises the supply of the pulp or mud to be classified, in a relatively shallow basin, the bottom of which is driven by a movement such that there are relative movements between this bottom and a layer of particles of a higher caliber supported by the bottom, and the provision of stationary jets of agitation water in the bottom zone of the basin, so that they are directed obliquely downwards towards the bottom of the basin, of so that the combined effect of the movement of the bottom and the action of the hydraulic jets will produce in the basin the grading conditions in which the solids can be maintained in a state of uniform grading in motion, with a minimum consumption of stirring water, while allowing rapid and precise adjustment from the point of view of the desired separation gauges,

   the machine being thus made

 <Desc / Clms Page number 6>

 capable of efficiently processing feed slurry containing even a wide range of particle sizes, from fines to coarse particles. The lower caliber fraction overflows at the upper end of the basin, while the higher caliber fraction or sands exits the basin moving through the sands discharge passage, against the adjustable back pressure of a hydraulic column maintained outside the basin, this column comprising a quantity of the solid particles of the fraction of sands which is discharged, and communicating with the column of mud represented by the basin itself, by said submerged passage.



   According to one embodiment of the invention, which moreover has no limiting nature, the invention uses a construction similar to that according to the aforesaid patent, in that it uses a circular basin. - relatively shallow ring, which is delimited by an oscillating circular bottom, a stationary cylindrical wall with peripheral overflow for the fraction of fines, an annular sand discharge passage, an annular sealing column along and to the outside said passage and defined by a sand discharge dam, which surrounds said passage and is spaced concentrically with respect thereto, a sand collecting chamber surrounding the sand discharge dam,

   a clear water column with an adjustable overflow barrier to control the density of the pulp in the basin and thus maintain a separation point at the desired caliber, and supply means arranged in the center to bring the pulp or slurry into the basin .



   The aims of the invention are achieved, in this exemplary embodiment, using a solid or non-perforated bottom, while stationary elements emitting jets for introducing and distributing the agitation water, are arranged. in a suitable arrangement with respect to one another and with respect to the foundation More particularly, these elements take the form of a set of structures with annular pipes emitting jets, arranged concentrically with respect to one another and concentrically to the vertical axis around which the bottom oscillates.

   These jet-emitting pipe structures are suitably spaced from each other in a horizontal plane which is, in turn, suitably spaced from the bottom, so that the jets emitted at an appropriate angle to the bottom, from each side of each of the pipes, will in fact produce an adequate and uniform distribution of the agitating water which will rise from the bottom in order to maintain the desired state of movement of the solid particles in the basin.



   Given that the invention can be carried out in various constructive forms, without departing from the spirit of the invention or from its essential characteristics, the embodiment envisaged is therefore given only as a By way of non-limiting example, the scope of the invention encompasses in particular the various variants which constitute in substance functional equivalents of the invention as defined in the present specification.



   In the accompanying drawings, Figure 1 is a schematic longitudinal sectional view of an embodiment of the classification apparatus according to the invention, in which the reservoir containing the classification basin for the pulp is provided with 'an oscillating bottom with a stationary system emitting water jets arranged above the bottom, the classification basin itself being arranged above said system and comprising a hydraulic equilibrium communication with a receiving tank of sands, which contains a body of clear water and comprises an inclined wall along which the sands or coarse fraction resulting from the separation is lifted to emerge from said body of water and is discharged afterwards water separation.

 <Desc / Clms Page number 7>

 



   Figure la is a detail sectional view taken along line la-la of Figure 1 and showing the height adjustment means.



   Figure They is a side view along the line Ib-lb. in figure 1.



   Figure 2 is a plan view of the apparatus according to Figure 1, showing a plan view of the jet water supply system, together with motor means operable to impart the oscillating motion to the plate. bottom of the classification basin.



   Figure 3 is a longitudinal sectional view taken along line 3-3 of Figure 2
FIG. 4 is a view on a larger scale of a detail of FIG. 3, showing a view in section of the means for supporting and maintaining the oscillating base.



   FIG. 5 is a view on a larger scale of a detail of FIG. 2, showing the pipes emitting jets, as well as the neighboring constructive elements.
FIG. 6 is a perspective view of annular jet emitting pipes, arranged concentrically in a horizontal plane spaced from the oscillating bottom plate.



   As shown schematically in Fig. 1, the grading apparatus comprises a relatively shallow grading bath or basin 10, which contains the pulp to be graded which is continuously fed therein, and a reservoir or a sand collecting chamber 11, arranged under and around the classification basin and being in effective hydraulic communication with it.



   In this embodiment, the classification basin is round and comprises a horizontal circular bottom plate 12 which forms part of an oscillating structure "0" mounted so as to oscillate about a vertical axis x - x. , this oscillating assembly being indicated by an annular thrust bearing 13 The mobile or oscillating structure "0" comprises said plate 12, as well as a central tubular part 14 rigidly fixed to the bottom 12 and extending upwards therefrom, this tubular part 14 terminating, at its upper end, in a flange 15 shown as forming the upper part of the thrust bearing 13.

   That is to say, the flange 15 is supported in an oscillating movement on a stationary annular support part 16, for example by means of anti-friction members or balls 17. The bottom plate 12 of the oscillating structure " 0 "is reinforced on its underside by a sheet metal structure 18 in the form of an inverted cone of low taper, while the central tubular member 14 is rigidly fixed to the plate 12 and to the cone 18.



   The classification basin 10 is also delimited by a stationary cylindrical wall 19 which is concentric with the vertical axis x - x and is rigidly fixed to the receiving chamber of the sand 11 and is supported by the latter, by means of a substantially horizontal and annular cover 20 In this way, the wall 19 is rigidly supported at a suitable distance "d" from the bottom plate 12, so as to form an outer annular passage 21 for the coarse fraction resulting from The diameter of the cylindrical wall 19 is smaller than that of the plate 12, so that the latter has a peripheral part in the form of an annular shelf 22 protruding outside the wall 19 and surrounding along the periphery of the shelf 22 or of the plate 12,

   a sand discharge bar 23 extends upwards to slightly below

 <Desc / Clms Page number 8>

 above the height of the sand discharge passage 21 In this way, there is formed in the latter, between the wall 19 and the dam 23, a functional plug acting between the classification basin 10 and a body of water clear water in the sands collection tank 11, although the sands continuously move through the passage 21 and flow over the submerged dam 23 to fall to the bottom of the collection tank 11.



   The cylindrical wall 19 has an overflow end 24 over which the fraction of the fines flows into an open collecting chute 25 to discharge through the outlet 25a. A cylindrical feed well is shown at 26, with the pulp entering it following arrow F.



   The illustrated supply system for the introduction by jets of the stirring water into the pulp bath of the classification basin comprises two annular injection pipes 27 and 28 arranged concentrically with respect to one another and with respect to the x - x axis.



   Each of these pipes is provided with two vertical supply pipes 27a. and 27b for pipe 27, and 28a and 28b for pipe 28. All of these vertical pipes are connected to a common supply manifold 29.



  Manually operated valves are provided at 30 for manifold 29, as well as at 30a, 30b, 30c and 30d for the various vertical pipes. The sand collecting tank 11 has an inclined bottom 11a along which the sand can be moved upwards to be discharged, for example by a suitable scraper mechanism II.12 ..



   In the construction according to Figure 1, it is important from the point of view of operation that in practical use of the machine, it is necessary to maintain an elevation "S" between the high level L1 of a body of clear water in the reservoir 11 and the low level L2 of the pulp in the classification basin. The magnitude of this elevation "S" must be able to be adjusted so that this adjustment makes it possible to establish a hydraulic back pressure of the desired magnitude to act on the sands which move outwards through the annular space between the passage 21 and the submerged dam 23. This back pressure of the desired magnitude is established by means of the clear water overflow "C" provided laterally by compared to the reservoir 11 and shown more clearly in Figures la and 1b.

   This overflow is placed in a side housing 30e, communicating with the interior of the reservoir 11 through the opening 30f provided in the corresponding side wall of this reservoir. 30g and 30h outlets of the 30e box allow the discharge of clear water and solids which may have reached the overflow "Cno
Since the height of the elevation "S" is balanced through the passage 21 through the pulp column in the grading basin, it follows that by a variation of said elevation a corresponding change of the density in the grading can be obtained. the pulp bath or classification basin, so that it is possible to obtain, by such a variation in the elevation,

   a corresponding displacement of the point of separation between the fine fraction which overflows and the coarse fraction of the sands passing over the submerged sand discharge dam 23.



   Figures 2, 3 and 5 show the essential parts of the apparatus in a more constructive form. The base of the apparatus is in fact represented by a reservoir 31 which receives the sands or the coarse fraction resulting from it. grading operation, and which is called a sands collecting reservoir. The sands are discharged into the reservoir 31 by a pulp bath or a grading area situated above, together with a necessary quantity of water, so that , since the coarse particles descend directly to the bottom of the reservoir 31, the latter always contains a mass of clear water, the sands of which must be extracted without water,

 <Desc / Clms Page number 9>

 for example by means of a lifting mechanism of any suitable type.



  The level of clear water in this tank must be kept at a suitable level L3, adjustable for example by means of an adjustable bar plate 32 or equivalent means, for example provided on a side wall of the tank. .



   This base of the apparatus or support structure 31 comprises an inclined bottom 33 which terminates at its lower end in a boot-shaped part 34 delimited by a wall 35 inclined slightly outwardly and a wall 36 inclined towards the outside. the interior The upper part of the base structure or reservoir 31 takes the form of a shallow basin 37, for example delimited by the wall 38 in the form of an inverted cone and connecting to the upper end of the boot 34 and to the walls 39 and 40 of the reservoir, and by a part of the cylindrical wall 41 forming the upper part of the bowl 37.

   This wall 41 forms the inner wall of an annular chute 42 receiving the overflow, and also delimited by an annular bottom 43 and an outer cylindrical wall 44, this chute 42 being provided to receive the fraction of fines overflowing from the classification basin. and then able to flow through outlet 45.



   From the upper end of the cylindrical wall 41 constituting the upper part of the bowl 37, an annular part 46 in the form of a shelf forming a cover extends inwardly and is connected to the upper end of the cup. wall 41 by a sealed connection. A vertical cylindrical wall 47 is rigidly connected, in particular welded, to the inner edge of the shelf 46 projecting inwardly, such that the horizontal connecting line or weld 48 extends horizontally between the upper edges. and lower of the cylindrical wall 47.

   In this way, an annular space 49 is formed around the lower part of the cylindrical wall 47 which is open downwards and in which a sand discharge dam 50 extends upwards, which dam is part of a oscillating structure O2 which will be described later. The lower end of the cylindrical wall 41 stops at a certain distance "d1" above the horizontal plate 52, thus forming a peripheral passage P for the discharge Sands.



   The actual classification bath in the bowl 37 is further defined by the oscillating structure O2 (corresponding to the structure O1 in FIG. 1) which comprises the horizontal circular plate 52 which is reinforced on its underside. by a sheet structure 53 in the form of an inverted cone of low taper.

   A tubular part or vertical column 54 is rigidly fixed to the center of the plate 52, for example by welding, the upper end of this column being supported by an annular support structure or thrust bearing 55 mounted on it. a stationary structure 56 which has a pair of parallel beams 57 and 58 which are rigidly connected to each other by a pair of shorter parallel beams 59 and 60, which are, in turn, connected to each other by a pair. re of even shorter beams 61 and 62. The beams 59 and 60 together with the beams 61 and 62 form a substantially square horizontal opening, the sides of which have a length "1" and through which the column 54 of the structure extends. oscillating O2.

   The beams 59, 60 and 61, 62 support the annular support or thrust bearing 55 (see also Fig. 4) by means of a plate 55a forming a cover. The support structure or bearing 55 comprises a lower stationary annular element or raceway 63 bolted to the beams of the structure 56, in particular at 63a, and a rotating or oscillating upper annular element forming a raceway 64, bolted to a flange. 65 formed at the upper end of the column 54, this fixing by bolts being indicated at 65a, anti-friction elements or balls 66 transmitting the vertical thrust of the oscillating structure 02 from the upper member 64 to the lower member 63 .

 <Desc / Clms Page number 10>

 



   The oscillating structure O2 comprises the sand discharge dam 50 which extends along the peripheral edge of the oscillating plate 52 and extends upwards, from this edge, into the aforesaid annular space 49 in the bowl 37, the height of this submerged dam 50 being slightly greater than the height of the passage for sands P, which is associated with this dam.

   The horizontal support structure 56 which sits above the classification basin is in this case also used as a mounting support for a pipe system 66 for supplying the agitation water into the classification bath. pulp, near the oscillating bottom 52 thereof.The water supply and distribution system, as shown in the drawings, comprises two circular jetting pipes 67 and 68 which are concentric with each other and by relative to the vertical axis of the oscillating structure 02.

   Each of these annular pipes 67 and 68 is formed by or subdivided into two semi-circular parts, so that the pipe 67 comprises the two halves 67a and 67b, connected by flanged connections 67c and 67d, while the pipe 68 also includes two halves 68a and 68b joined by flanged connections 68c and 68d. The various parts of the pipes 67 and 68 are supplied by corresponding vertical pipes 70, 71, 72 and 73 which are connected to a horizontal manifold 74 provided with a central supply pipe 75. A control valve 76 is provided in the central pipe 75, while adjustment valves 77 and 78 are provided in the supply pipes 71 and 72 respectively, and adjustment valves 77a and 78a are provided for the pipes 70 and 73.



   Each of the circular pipes 67 and 68 is provided over its entire length and on each of its sides with a row of ejection holes 79 which are arranged so that the water jets are emitted downwards, under an angle "w" to the bottom oscillating plate 52. A suitable magnitude for this angle "w" is on the order of 20 below the horizontal, if there is a gap of about 1 inch ( about 2.54 cm.) between pipes 67 and 68 and the bottom 52.



   Means are provided on the upper support structure to allow adjustment of the pipes 67 and 68 or the jet emitting pipe system with respect to the bottom of the classification basin, which allows the interval between the pipes 67 to be adjusted. and 68 and the bottom.



   The pulp to be classified is brought to the pulp bath, on the oscillating bottom 52, by a supply pipe 80 leading to a vertical circular stationary deflector 81, concentric with respect to the oscillating structure O2 and supported by the face. lower of the structure 56 by means of angles 81a. This deflector 81 is surrounded by an annular feed well 82 which is joined to the auxiliary bottom 52, from which it extends upwards.

   This means that the oscillating feed well 82 comprises a vertical cylindrical wall 83 and a horizontal annular bottom 84, which is at a distance "q" from the horizontal bottom plate 52 and constitutes, with the cylindrical wall 83 and column 54, annular receiving trough or feed well 82, feed openings or passages 85 being provided in wall 83, through which the feed slurry enters the classification bath radially in all directions, from the feed well 82.



   The concentric jet-emitting pipes 67 and 68 are shown to be spaced a distance "s" from each other (see Fig. 5), while the distance between the pipe 67 and the inner wall 83 delimiting the classification bath is half of "s", and the distance between pipe 68 and the outer wall 47 delimiting this bath is also half of "s". In a practical example, this distance "s" is for example 6 inches.

 <Desc / Clms Page number 11>

 



   A device for actuating or setting in motion the oscillating structure 02 has been shown in the aforesaid US patent? 2,302,588 and it will suffice to represent it here in a schematic way. In the drawing, this control device is mounted on the structure 56 and comprises a rigid horizontal arm 86 extending from the upper element 64 of the thrust bearing, an eccentric 87, a connecting rod 88 connecting the outer end of the arm 86 to the eccentric 87, and motor-actuated drive means 89, for producing rotation of eccentric 87. Structure 56, as shown, includes a horizontal extension 90 forming an auxiliary frame to serve as a mounting bracket. to a part of the operating mechanism comprising the eccentric 87.



   For demonstration purposes only, some constructive and functional data of an example of a practical realization will be given below.
In this example, the filing basin takes the shape of an annular space having an outside diameter of 42 "(1" = about 2.54 cm), a width of 12 "and a depth of 9", having an effective surface area. 7.8 square feet (1 foot = approximately 30.5cm).

   The jets emitting pipes are made of seamless tube, having a diameter of ± ", that is to say a
8 0.666 inch inside diameter and 0.42 inch wall thickness, two concentric tubes being provided with a spacing of 6 "from each other and 3" from the outside wall and the wall inside the basin respectively. Each of these pipes is provided with two vertical supply pipes formed by tubes with a diameter of 1 "and arranged at diametrically opposed points.



   There are a total of 288 ejector holes distributed over the bottom of the filing basin and having a total area of 1.79 square inches, each hole having an area of 0.00622 square inch, and the hole spacing being 5 degrees. center to center At a speed of 25 gallons per minute (1 gallon = approximately 4.54 liters) the pressure drop across the ports is 1 foot water column o The ports are arranged on both sides of the pipes and are directed towards the bottom, at an angle of approximately 20 degrees below the horizontal. The interval between the jetting pipes and the bottom was 1 "in a practical example, but was adjustable by the provision of means for raising or lowering the pipe system.



   In this example, 225 oscillations were imprinted on the bottom per minute, so that the peripheral stroke at the sand discharge passage was about 3 1/2 ". The sand discharge passage was 1 / high. 2 ", while the submerged sand discharge dam was 3" high.



   4
The feed to the grading basin was a mixture of loosened sands having a particle size range of -20 to -200 Tyler mesh (passing through the 20 and 200 linear inch sieve, respectively). a feed of 105.9 tonnes per day (weight of dry matter) a fraction of sands or coarse particles of 92.6 tonnes per day (dry matter) and a fraction of fines of 13.3 tonnes per day (material dried). By maintaining a 5 1/2 "" boost "and introducing the agitation water at a flow rate of 38 gallons per minute, the separation point, in terms of particle size, was 174 microns.



   A sieving analysis of the feed, the coarse fraction and the fine fraction, gave the following results

 <Desc / Clms Page number 12>

 
 EMI12.1
 
<tb> Sieve <SEP> Feed <SEP> Fraction <SEP> Fraction
<tb>
<tb>
<tb> coarse <SEP> from <SEP> fines,
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Mesh <SEP>% <SEP> total <SEP> of <SEP> solid <SEP> materials <SEP> retained <SEP> by <SEP> on
<tb>
<tb>
<tb>
<tb> (Tvler) <SEP> sieve.-
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 20 <SEP> 11.0 <SEP> 11.0
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 28 <SEP> 19.7 <SEP> 21.6
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 35 <SEP> 33.1 <SEP> 35.4
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 48 <SEP> 51.5 <SEP> 56.5
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 65 <SEP> 71,2 <SEP> 82, <SEP> 6 <SEP> 0, <SEP> 04 <SEP>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 100 <SEP> 86,

  7 <SEP> 96.3 <SEP> 20.7
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 150 <SEP> 95.7 <SEP> 99.4 <SEP> 78.0
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 200 <SEP> 99.0 <SEP> 99.9 <SEP> 99.9
<tb>
 
CLAIMS.



   1 - Apparatus for the hydraulic grading treatment of a pulp containing a mixture of a range of sizes from fines to coarse particles, to separate the mixture into a fine fraction and a sand fraction, called respectively particles of lower caliber and particles of higher caliber, which apparatus comprises a reservoir for containing a grading basin to which said mixture is continuously supplied, while particles of lower caliber discharge at the upper end of the basin and particles of a larger size are discharged at the bottom of the basin, said basin comprising a movable horizontal bottom structure,

   motor means for imparting to this structure a horizontal movement such that there will result a relative movement between said bottom and the coarse particles supported by the latter; adjustable water supply and distribution means penetrating from above into said basin and having lower water ejection parts located in the bottom area of the basin and spaced from said bottom, for introducing and distributing water. auxiliary agitation water with an adjustable flow rate towards said bottom and arranged in such a way, relative to the bottom, that this water effectively rises in a manner substantially uniformly distributed from this bottom, which in turn has the effect of forming and maintaining in said basin a zone of sands particles of higher caliber in the bottom of the basin,

   a zone of lower caliber fines in the upper part thereof, and an intermediate zone containing a mixture of higher caliber and lower caliber particles in a state of instability or hesitation, an overflow dam being provided for the discharge of particles of smaller size from said upper zone of the basin, and adjustable means being provided for controlling the rate of discharge of the sand from the bottom zone of the basin and for adjusting the point of separation between the lower size and the higher caliber, so that, thanks to the combined action of the horizontal movement of the bottom and the upward flow of stirring water, one can obtain a fraction of fines and a fraction of sands, which are each practically free of particles of the other fraction.

   

** ATTENTION ** end of DESC field can contain start of CLMS **.


    

Claims (1)

2 - Apparatus for the hydraulic grading treatment of a pulp containing a mixture of a range of sizes from fine to coarse particles, to separate the mixture into a fraction. <Desc / Clms Page number 13> tion of fines and a fraction of sands, called lower-caliber particles and higher-caliber particles, respectively, which apparatus comprises a reservoir for containing a classification basin in which this separation is carried out, the mixture being continuously brought into this basin, while particles of lower caliber discharge at the upper end of the basin and particles of higher caliber discharge at the bottom of the basin, said basin comprising a wall structure which delimits it and a bottom structure movable horizontally with respect to the latter and in sealing relationship therewith, said bottom structure comprising a horizontal surface for supporting a layer of particles of size upper, motor means for imparting to the bottom structure a horizontal movement such that there will result a relative movement between said support surface and the particles of higher caliber of said short bottom, maintaining said relation d sealing; adjustable means for supplying and distributing water, penetrating from above into said basin and comprising lower water ejection parts situated in the bottom zone of the basin and spaced from this bottom, for emitting and distributing auxiliary agitation water with an adjustable flow rate in the direction of said bottom, and arranged in such a way with respect to the bottom that this water effectively rises in a manner substantially uniformly distributed from this bottom, which has, in its turn, tower has the effect of forming and maintaining in the basin an area of larger particle sands in the bottom of the basin, an area of fine particles of smaller size in the upper part of the basin, and an intermediate area containing a mixture particles of lower caliber and higher caliber in a state of instability or hesitation, an overflow dam being provided for the discharge of particles of a size smaller than said upper zone of the basin, and adjustable means for controlling the rate of discharge of the sand from the bottom zone, the latter means comprising a passage for discharge of sand at the periphery of the basin between said bottom and the wall delimiting the basin, delimitation means providing a column of sand outside said passage, and adjustable means for controlling the discharge rate of the sand from this column of sand and thus adjust the point of separation between the lower gauge and the upper gauge, so that by the combined action of the horizontal movement of the bottom and the upward flow of agitation water, lower size and larger size fractions can be obtained which are each substantially free of stray particles from the other fraction. 3 - Apparatus according to claim 2, wherein said motor means comprise a mechanism for producing a substantially rectilinear reciprocating movement. 4 - Apparatus according to claim 2, wherein said water ejection parts comprise pipes spaced from the bottom and extending horizontally, substantially in the direction of said reciprocating movement, said pipes having orifices arranged to emit jets of water towards said bottom, directed sideways and obliquely downwards. 5 - Apparatus according to claim 2, wherein the direction of said reciprocating movement is substantially transverse to the general direction of progression of the particles in the basin towards the discharge. 6 - Apparatus according to claim 2, wherein said adjustable sand discharge control means comprise a sand reception chamber surrounding and enclosing said outer delimiting means and the sand column therein, said receiving chamber providing a Clear water column provided with an adjustable overflow, this overflow being adjustable to adjust the separation point in a corresponding way. <Desc / Clms Page number 14> 7 - Apparatus for hydraulically classifying a pulp containing a mixture of a range of sizes from fines to coarse particles, to effect separation of the mixture into a fine particle overflow fraction and a fraction of sands forming at the bottom, called respectively lower-caliber particles and higher-caliber particles, which apparatus comprises a classification basin in which said separation takes place and to which said mixture is continuously fed, said basin being delimited by a stationary cylindrical wall, a circular bottom substantially concentric with respect to this wall and located at a certain distance below the latter to form an annular discharge passage for the sands, structures and support means arranged above the basin to centrally support said bottom with a view to the oscillatory movement of the latter, with motor means for imparting this oscillatory movement to said bottom, a peripheral sand discharge dam , extending upwards from the peripheral part of the bottom and arranged at a certain distance from said passage, this dam rising above the upper edge of said passage and being capable of containing a column of sands which lie in migration outwards towards the sand discharge dam and constituting a sealing plug in service, a stationary sand reception chamber, surrounding and closing against said stationary wall delimiting said basin by enclosing said sand discharge dam and providing a clear water column provided with an adjustable overflow, adjustable means for removing sands from said chamber of receiving, and adjustable means for supplying and distributing water, penetrating from above into said basin and comprising lower water ejection parts located in the bottom area of said basin and spaced from said bottom, for ejecting and distributing the auxiliary agitation water, with an adjustable flow rate, towards said bottom, and arranged in such a way with respect to this bottom that said water effectively rises in a manner substantially uniformly distributed from the bottom, thereby , in turn, has the effect of forming and maintaining in said basin a zone of sands with particles of higher caliber, at the bottom of the basin, a zone of fines of lower caliber in the upper part of the basin, and an intermediate zone containing a mixture of particles of caliber lower and higher caliber particles in a state of instability or hesitation, an overflow dam being provided for the discharge of the fine fraction from the upper zone of the basin. 8 - A hydraulic filing apparatus, substantially as described above and shown in the accompanying drawings.