LU85987A1 - FILTERING METHOD AND DEVICE FOR IMPLEMENTING THE METHOD - Google Patents

Description

ë "Filtering method and device for implementing this method" ________ ^ ---------- The present invention relates to a filtering method i as described in the preamble to re-5 vendication 1. It also relates to a filtering device as described in the preamble of claim 4.

Filter presses of this type are known whose front walls of the filter plates are at least partially flexible and are partially displaceable under the action of a pressurized fluid. These front walls are however fixed at their periphery where they are hooked to the peripheral frame of the filter plate, and possibly in their center 15 when the filter press has a central feed inlet (see for example patent applications in France no.2.384.526 and no.2.398.529, the patent in: United States of America no.3.926.811, and the European patent application no.81.715). These front plots of flexible material, however, have the drawback of rapid aging of this material under the conditions to which they are subjected and their fixing notes represent a large section this filtering chamber not directly subjected to ma-25 ximal compression , which results in a loss of yield. Finally, the filter cake obtained in the filter chambers easily adheres to the supported filter fabrics! 'on these frontal walls and they also in ce- * formable material. Also complicated and expensive devices for separating the filter cake after the filter press has been defeated.

5 The present iridescent. aims to avoid the aforementioned drawbacks and make the filtering process as profitable as possible for you, in a simple manner.

Your problems are solved, according to the invention, by a method having the characterizing features of claim 1, as well as by a device having those of claim 4.

Other advantageous embodiments and features of this method and of this device are also indicated in the subclaims 15 dependent on these claims 1 and 4 respectively.

Other details and particularities of the invention will emerge from the description given below without implied limitation and with reference to the attached drawings.

FIG. 1 represents a view in axial section of a filtering plate of a filtering device according to the invention.

FIG. 2 represents a view in partial axial section of two filter plates assembled in a filter device according to the invention, one of these filter plates being represented in two of its positions during the filtering process.

Figure 3 shows the filter plate on the left in the figure - in a third po-30 sition.

Identical or analogous elements are designated in the different figures by the same references.

As can be seen from FIG. 1, the filtering plate 1 shown comprises a peripheral frame 2 in rigid annular form "which in cross section can have any configuration, for example circular or of regular or irregular polygon, as well as those front walls 3 and 4. In the example illustrated, the two front walls 3 and 4 are in accordance with the invention arranged in the filter plate so as to be able to slide axially in the peripheral frame 2.

In the example illustrated in FIG. 1, each front wall 3, 4 comprises a filtration means in the form of a perforated plate, a lattice or a filter cloth 5, 6 made of rigid material, for example made of metal or hard plastic, this filtration means constituting the face of the front wall which is adjacent to the filtering chamber 9 (see FIG. 2) formed between two filtering plates. This filtration means 5, 6 is supported on a plate-shaped support 7, 8 which is disposed on the side of the filtration means 5, 6 which is opposite to the corresponding filter chamber 9 and which is capable of sliding sealingly in the peripheral frame 2. To ensure this tightness, a seal 10 is for example housed in a peripheral groove 11 of the support plate 25, 7, 8. In the illustrated embodiment the plates support 7 and 8 are arranged parallel to each other and perpendicular to the axis 12 of the filter chambers 9. They support the filter movens 5. 6 at a certain distance from their outer front face 13, 14 , by means of a spacer ring 15, 16. For fixing these on the corresponding support plate, there are provided fixing means, for example holes 17 arranged along the peripheral edge of the glamies this support, internal tap holes 1S correspcr. dants cens the spacer rings lo, 16 and not shown clamping screws cooperating with the threaded bores 1S through the holes 17. the filtration means 5. 6 are t sandwiched between a spacer ring 15. Ιό and a external clamping ring 19 which is fixed to the spacer ring by clamping screws (not shown) cooperating with external threaded bores 20 of this ring and passing through holes provided in the periphery 10 follows cinch to the clamping 19. Each filtration means 5, 6 forms in the example illustrated a flat face arranged and maintained perpendicular to the axis 12 of the adjacent filtration chamber 9.

In the embodiment shown in FIG. 1, the filtering chambers 9 are supplied with material to be filtered by means of a radial supply conduit 50 which passes through the »peripheral frame 2 at a location where it is located in front of the filter chamber 9 when the front wall 20 is in the retracted position inside the filter plate (as shown in dashed lines in FIG. 2).

The compartment 32, 33 formed between each rigid filtration means 5, 6 and its support plate 25 7, 8 is used for collecting the filtrate and the washing and compression effluents. In the exemplary embodiment illustrated, an outlet duct 34 crosses the peripheral frame 2 in a position which remains between your two movable support plates 7, 8 even in their pcsitior. of 30 withdrawal. This duct 34 is connected, via a T branch 35 and two extensible ducts 36 and 37. for example, iiexÎDies ducts arranged in a helix, accordion-shaped ducts or the like, to passages 38 and 39 provided through the plates this support / in £. these p & ssstcs thus put the harvesting compartments 32 and 33 in communication with the outlet conduit 34 and allow the evacuation of these washing effluents and of the tors filtrate from the press press.

In the embodiment illustrated in FIG. 1, the means allowing the displacement of the front walls 3 and 4 consist of a source of energy not shown, in this case a source of air 10 under pressure, which is put in communication with the pressure chamber 40 formed between the support plates 7 and 8 and the peripheral frame 2, via one or more inlet and / or outlet ducts for pressurized air 51, arranged so as to tou-15 jours lead into the chamber 40 even in the position of withdrawal of the front walls 3 and 4. By a modification of the pressure inside the chamber 40 we can thus spread or bring the front walls 3 closer and 4. Stop means, not shown, may even be provided to limit the axial sliding movement of the front walls 3 and 4 between an extreme withdrawal position and an extreme opposite position.

In the chamber 40 2d are also provided means for guiding these transverse walls 8 and 4, which guarantee perfect translational movement of the front walls 3 and 4, and in particular of their faces closed by this filtration means 5 and 6, according to the axis 12 of the chambers this filtering. The guide means illustrated in FIG. 1 consist of bars 41, 42 articulated in their center, in a cross, on a pivot axis 43 perpendicular to the axis 12 and fixed to the peripheral frame 2. These bars 41, 42 are each articulated on the two support plates 7 and 8 by their ends.

FIG. 2 illustrates an alternative embodiment of the filtering device according to the invention. The left-hand filter plate only has a single movable front wall, wall 3, while front wall 4 'is fixedly connected to peripheral frame 2, for example by bolting. Such a filter plate can be used, as illustrated in FIG. 2, this end plate in an assembly where the other filter plates of the filter press have two movable front walls, or one could also provide an assembly of filter plates such as that shown on the left in FIG. 2 so that each filter chamber is formed from a movable front wall and from a fixed front wall.

In FIG. 2, the filter plates have a central supply. The filtering chambers 9 are supplied with material to be filtered 20 by means of an axial supply duct 21 which simultaneously serves as a guide for the front walls. The sealing of the support plate 7 with respect to the peripheral surface of the conduit 21 is obtained by an annular seal 22 housed in an internal circumferential groove 23 of the central opening 24 formed in the support plate 7 for the passage of the con duct 21. In the center a second spacer ring 25 is fixed to the support piece 7, by fixing means identical to those described for the first spacer ring 30. The filtration means 5 also has a central opening 26 for the passage of the spacer ring 25, and it is clamped between the second spacer ring 25 and a second clamping ring 27 by me worms. s of fixing identical to those described * for the uremier ring this serrare 1 “·.

, The ring o spacing _ o resente advantageously also a seal 28 housed in an external peripheral groove 29 and the ring of ear-o tement 25 a gasket ui lightness in an internal circumferential groove it .

In the exemplary embodiment of a filter plate illustrated on the left in FIG. 2, the supply duct 21 is fixed to the fixed front wall 4 ′ 10 and its mouth in the filter chamber 9 is located slightly below the plane formed by the front edge 47 of the peripheral frame 2, so as to leave a passage for the material supplied, between the ends of the supply conduits 21 of the two filter plates as-15 seemingly.

As can be seen in FIG. 2, the means for moving the front plate 7 here consist of a source of motive energy, in this case a source of hydraulic energy not shown, and of one or more jacks 44 arranged in the chamber 40 formed by the front walls 3, 4 and the peripheral frame 2. These jacks supplied with hydraulic medium from said source, not shown, act on the back of the support plate 7 to advance or retract it by 25 so aue the filtration means 5 moves in a translational movement along the axis 12 and in a plane perpendicular thereto.

The operation of the filtering device illustrated in FIG. 2 is as follows.

In the position shown in phantom, the front wall 3 is in the position of extreme withdrawal, following the withdrawal of the piston rods 45 from the jacks 44. This position is the starting position, in which the filter plates are assembled .

l assernDiSge is carried out in a leaktight manner between _es ”plates this filtering by means of a compressed annular seal between the two front edges 47 these ——— * -” a p; u_Lue T2u. ^ ncrocuite in each chamber of -> j—> .i. ~~ t: n by x - .. nL-crmeciatre conouou q aiimenta- ticn, in this case the axial conduit 21 which opens into the filtering chamber 9.

After filling the filter chambers, precompression may possibly take place before washing, by reducing the volume of the filter chambers by moving the front walls of the filter plates towards the filter chambers. The liquid phase, that is to say the filtrate, flows through the filtration means 5, 6 and is collected in the collection compartments 32 and 33, from where it is discharged through the passages 38, 39, the expandable conduits 36, 37 and the outlet conduit 34.

Then washing water is introduced into the filtering chamber, either by the supply line 21 itself, or by separate pipes, not shown, opening for example into the harvesting compartments 32 and 33 The washing solution is discharged in the same way as the precompression liquid.

25 The final compression can then take place by a displacement of the front walls to the position shown in FIG. 2, that is to say slightly recessed inside the filter plates. The filtering chambers 9 are then reduced to the minimum volume allowed by the solid phase.

. The operation of the filter plate illustrated in FIG. 1 is essentially the same, apart from the radial supply of material to be filtered and the use of pneumatic displacement means.

The filter press is then stripped. The filtering plates are therefore separated and at this time the cake this tiltration can fall, in any case partially, for example in a hopper not shown. To guarantee total elimination of the filter cake, the front walls 3, 4 are advanced to their extreme position, for example that shown in FIG. 3, where the filtration means 5 is stopped beyond the plane formed by the front edge 47 of the peripheral frame 2. It is also possible to provide for the extreme position of the front walls to be limited to this plane, as illustrated in FIG. 1.

As can be seen during all the movements of the front walls and in all their positions, the front walls are maintained in the same relative position relative to the axis 12 of the filtering chambers, and in a plane perpendicular to the this one. This results in a compression of the material to be filtered, which is uniform over the entire section of the filtering chambers and throughout the duration of the compression and possibly of the precompression, which has the effect of a more efficient filtering.

The arrangement according to the invention further allows the use of rigid filtration means in the form of thin perforated plates, particularly smooth on their face facing the filtering chamber. Not only these means of filtration. are much more resistant to '^ ae-iiissenent than the flexible filtration means hitherto used, but they also allow an easy evacuation, by gravity, of the filter cake obstructed, - ^ r especially when advanced outside their filter plates.

vention is in no way limited to: ·: realization farms described above and that your uOGixn.es-tions can be made without departing from the scope of this 5 patent.

One can for example imagine other means of moving the front plates, for example by means of electric, electromagnetic or other motors.

10 It is also possible to provide means for guiding the front walls different from the cross bars 41, 42 or from the axial duct 21.

The arrangement of the supply pipes for the filter material and washing liquid, and the outlet pipes for the filtrate and the washing solution can be designed in a very variable manner.

As already said, it is possible to imagine filter plates with two displaceable front walls or with a single displaceable front wall, each filter chamber then being formed of a displaceable front wall 3 and of a wall fixed front 4 !. In the case of filter plates with two movable front walls and supplied by an axial duct 21, provision must be made for the latter to be suitably fixed to the peripheral frame 2, between the support plates 7, 8.

One can also imagine that the plates 5, 6 are not filtering had on part of their surface, for example to increase: 'their rigidity.

30

Claims (10)

2. Filtering method according to claim 1, characterized in that the face, adjacent to the corresponding filtering chamber, of each displaceable front wall is arranged in a plane perpendicular to the axis of the filtering chamber and maintained in this position during its translational movements. 3. Filtering method according to either of claims 1 and 2, characterized in that the face, adjacent to the corresponding filtering chamber. of each movable front wall is moved according to said translational movement between ure posi-3û tion extreme withdrawal, where it is located inside the front edges of the filter plate, and an extreme opposite position, where it is located flower of said front edges or possibly slightly projecting outwardly therefrom. 4. Filtering device of the filter-press type comprising several fij plates. trage seated and forming between them binding chambers as well as at least one entry in each wire chamber-5 trage, for the introduction of the auger to be filtered, each filter plate comprising a rigid peripheral frame and two rrontaj.es walls, at least one of which is, by displacement means, movable towards the filter chamber and in the opposite direction, each front wall 10 comprising a filter means and a support for the latter as well as at least an outlet for the filtered liquid, characterized in that the entire face of each movable front wall, which is adjacent to a filtering chamber, has a relative position relative to the axis of this filtering chamber which is identical in all the positions of this front wall during filtering, and in that this face is formed at least partially by the filtration means. 5. Device according to claim 4, characterized in that each of said faces is arranged in a plane perpendicular to the axis of the corresponding filtering chamber. 6. Device according to either of claims 4 and 5b characterized in that it comprises means for guiding the detachable front walls which guarantee an exact translation of these. 7. Device according to any one of claims 4 to 6, characterized and this eue the means 30 of filtration are fabrics, lattice, or perforated slaps. S. Device according to any one of claims 4 to 7, characterized in that the support of the filtration means is a place which is arranged T, on the side of the filtration means which is opposite to the filtration chamber and which is capable of sliding in leaktight manner in the peripheral frame of the filtering plate, this plate forming between it and the filtration means a compartment that revolts from the filtrate. 9. Device according to any one of claims 4 to 7, characterized in that the means for moving the movable front walls comprise a source of motive power and means for transmitting it on the side of the movable front walls which is opposite to the corresponding filter chambers. 10. Device according to claim 9, characterized in that it comprises, as a motive energy source, a fluid compressor and, as transmission means, a sealed pressure chamber by filtration plate, capable of acting on the sides of the filtration medium supports, which are opposite to the filtration chambers, as well as a supply connection capable of placing the compressor and the pressure chamber in communication. 11. Device according to claim 10, characterized in that the sealed pressure chamber of a filter plate is formed by the peripheral frame and the two front walls. 12. Device according to claim 10, characterized in that the sealed pressure chamber is formed by one or more cylinders, the piston rods of which act on the first support plates of the 3O movable front walls. 13. Device according to any one; of claims 4 to 12, characterized in that it comprises at least one filtering plate whose two front walls are movable. »1-4. Device according to any one of claims 4 to 12, characterized in that it comprises at least one filtering plate, one of the two wall walls of which is the table and the other fixed. 5 on. Device according to any of these claims S to 14, characterized in that to each filtrate collection compartment is added an evacuation means capable of accompanying the collection compartment during its movement. 10 lbs. Device according to any one of Claims 4 to 15, characterized in that the said inlet for the material to be filtered is arranged so as to open out radially into the filtering chamber at least in a position for withdrawing the front walls 15 movable at the interior of the filter plates, v 17. Device according to any one of claims 4 to 15, characterized in that said inlet for the material to be filtered consists of the mouth of an axial duct on which the movable front plates 20 are capable of sliding in leaktight fashion, this axial duct simultaneously serving as a guide means to guarantee the front walls an exact translation. 95 'me-; ···? : _______ 5 ..... rmrmm · v. ...... d ...... rm: - U -. '-. "“ Rdîd ....... J ...: 30 m V- 4.;. Mmm-m f »* 5 * * -, ';. -" - 4 {* - w "" \